GIT a7f922a02ff467b0e28ee45296b0a3c56f1d5ea3 git+ssh://master.kernel.org/pub/scm/linux/kernel/git/jsipek/unionfs.git commit Author: Erez Zadok Date: Mon Feb 12 12:36:42 2007 -0500 Unionfs: Documentation update Be little gentler & updated the URLs Signed-off-by: Erez Zadok Signed-off-by: Josef 'Jeff' Sipek commit 5d5541179e3136795473fd42ba5aad70eecbad8f Author: Josef 'Jeff' Sipek Date: Tue Feb 6 19:34:11 2007 -0500 fs/: Move eCryptfs & Unionfs config options into a sub-menu Using The Misc filesystems sub-menu for layered/stackable filesystems only makes it harder for users to find eCryptfs/Unionfs. Additionally, the menu can be easily turned into a menuconfig, which could be used to turn on any VFS/VM functionality required by layered filesystems (there is none at the moment). Signed-off-by: Josef 'Jeff' Sipek Signed-off-by: Michael Halcrow commit 2bbcc92b7896b6526b306a0fe4507cac2e872e5f Author: Josef 'Jeff' Sipek Date: Sun Feb 4 14:52:48 2007 -0500 fs/unionfs/: Use __roundup_pow_of_two instead of custom rounding code Signed-off-by: Josef 'Jeff' Sipek commit aadad9173d83c33c54772755a280012128424462 Author: Josef 'Jeff' Sipek Date: Sun Feb 4 14:52:48 2007 -0500 fs/unionfs/: Don't duplicate the struct nameidata The only fields that we have to watch out for are the dentry and vfsmount. Additionally, this makes Unionfs gentler on the stack as nameidata is rather large. Signed-off-by: Josef 'Jeff' Sipek commit 5931caca1ac965047e372854e67df1b270a1cf3b Author: Josef 'Jeff' Sipek Date: Sun Feb 4 14:52:48 2007 -0500 fs/unionfs/: Andrew Morton's comments - rename {,un}lock_dentry to unionfs_{,un}lock_dentry - few minor coding style fixes - removed prototypes from .c files - replaced dbstart macros etc with static inlines - replaced UNIONFS_D(d)->sem semaphore with a mutex - renamed sioq struct workqueue to superio_workqueue - made unionfs_get_nlinks and alloc_whname not inlined Signed-off-by: Josef 'Jeff' Sipek commit 04f4a7d6b4326497dd40443d9528006ec6cff3c6 Author: Adrian Bunk Date: Sun Feb 4 14:52:47 2007 -0500 fs/unionfs/: possible cleanups This patch contains the following possible cleanups: - every function should #include the headers containing the prototypes of it's global functions - static functions in C files shouldn't be marked "inline", gcc should know best when to inline them - make needlessly global code static - #if 0 the following unused global function: - stale_inode.c: is_stale_inode() Signed-off-by: Adrian Bunk [removed stale inode related fixes as stale_inode.c is gone] Signed-off-by: Josef 'Jeff' Sipek commit d520fafc3d4a7c29e2634db777bc83c482c4cba6 Author: Josef 'Jeff' Sipek Date: Sun Feb 4 14:52:47 2007 -0500 fs/unionfs/: Remove stale_inode.c The stale inode operations were heavily based on bad inode operations. This patch removes stale_inode.c and converts all users of stale_inode_ops to bad_inode_ops as there seems to be no reason to return ESTALE instead of EIO. This is the more appropriate than porting the bad_inode.c fix (commit be6aab0e9fa6d3c6d75aa1e38ac972d8b4ee82b8) to stale_inode.c. Signed-off-by: Josef 'Jeff' Sipek commit 115e3127b8e5b4abb26a5df45f47be38d0f8cabe Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:47 2007 -0500 Unionfs: Extended Attributes support Extended attribute support. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit ecf1d9ff8516a2597070b03d1764c1727a8bdae5 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:47 2007 -0500 Unionfs: Kconfig and Makefile This patch contains the changes to fs Kconfig file, Makefiles, and Maintainers file for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit e8ecb34110846d061875f678459a5271554fe5b2 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:47 2007 -0500 Unionfs: Unlink This patch provides unlink functionality for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit f9bbcdcd2cce2b633a320130f4a1f4cf58f1a7be Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:46 2007 -0500 Unionfs: Include file Global include file - can be included from userspace by utilities. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 907cdfcb29f70a96df774be2148347a24b6d96a7 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:46 2007 -0500 Unionfs: Internal include file This patch contains an internal Unionfs include file. The include file is specific to kernel code only, and therefore is separate from include/linux/unionfs.h. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 0902c023f27d9af59eaf097e9f4421a7d4e3dee5 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:46 2007 -0500 Unionfs: Helper macros/inlines This patch contains many macros and inline functions used thoughout Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit d1d3a01f5e1ccaa5c70f2c462641933b90385c6d Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:46 2007 -0500 Unionfs: Handling of stale inodes Provides nicer handling of stale inodes. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit e98edf0264be3ac0d8533211884abf21408800cd Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:46 2007 -0500 Unionfs: Superblock operations This patch contains the superblock operations for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit ed0dfa007860769248687fef1b4964e45fc16f0f Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:46 2007 -0500 Unionfs: Miscellaneous helper functions This patch contains miscellaneous helper functions used thoughout Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit fb9a413a14363e4e46fb6b202375db613fab28d9 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:45 2007 -0500 Unionfs: Privileged operations workqueue Workqueue & helper functions used to perform privileged operations on behalf of the user process. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit c57cf4863f536bc0a8ae4509f1f2d2dd00d72684 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:45 2007 -0500 Unionfs: Rename This patch provides rename functionality for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 0e6fd7343fd3a5522ae2d3bd9670da77b7ebe474 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:45 2007 -0500 Unionfs: Readdir state This file contains the routines for maintaining readdir state. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit a381317d865f39adeaade2941e6ca82ddd0468a4 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:45 2007 -0500 Unionfs: Main module functions Module init & cleanup code, as well as interposition functions. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit aea862b28dacac6048518cbb86902c0f03acf7fb Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:45 2007 -0500 Unionfs: Lookup helper functions This patch provides helper functions for the lookup operations in Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 94b8fa9c2c1d761b2c1a0a48827345d6d9ebdced Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:45 2007 -0500 Unionfs: Inode operations This patch provides the inode operations for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit c16ac4b735bda1f31c26d685e52757b8cd59a53d Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:44 2007 -0500 Unionfs: Directory manipulation helper functions This patch contains directory manipulation helper functions. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 0c0145d9b4dfdc84929d65ea0b394eb2a5075521 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:44 2007 -0500 Unionfs: Directory file operations This patch provides directory file operations. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 1f6819238add80e571572a43e963186cc77370d8 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:44 2007 -0500 Unionfs: File operations This patch provides the file operations for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 7fdbdcc888c1b59d531f78b95cfeb2e52fa8d6a3 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:44 2007 -0500 Unionfs: Dentry operations This patch contains the dentry operations for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 8b1200f3c7e3358ba448f8112e2c8ccef9e80750 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:43 2007 -0500 Unionfs: Copyup Functionality This patch contains the functions used to perform copyup operations in unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit c1ccef41a14e6a321ba5319b14d1dcd352f75bf9 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:43 2007 -0500 Unionfs: Common file operations This patch contains helper functions used through the rest of the code which pertains to files. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit efb1bf06f1ae3c004c3f731ab3dafe79ed65ed9d Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:43 2007 -0500 Unionfs: Branch management functionality This patch contains the ioctls to increase the union generation and to query which branch a file exists on. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok commit 7f476357a4aa1d4933364e2cde8080298ebdc054 Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:43 2007 -0500 lookup_one_len_nd - lookup_one_len with nameidata argument This patch renames lookup_one_len to lookup_one_len_nd, and adds a nameidata argument. An inline function, lookup_one_len (which calls lookup_one_len_nd with nd == NULL) preserves original behavior. The following Unionfs patches depend on this one. Signed-off-by: Josef "Jeff" Sipek commit 213825a7578ea761cf4127f1d2dae67200b9f60e Author: Josef "Jeff" Sipek Date: Sun Feb 4 14:52:43 2007 -0500 Unionfs: Documentation This patch contains documentation for Unionfs. You will find several files outlining basic unification concepts and rename semantics. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok Documentation/filesystems/00-INDEX | 2 Documentation/filesystems/unionfs/00-INDEX | 10 Documentation/filesystems/unionfs/concepts.txt | 70 ++ Documentation/filesystems/unionfs/issues.txt | 23 + Documentation/filesystems/unionfs/rename.txt | 31 + Documentation/filesystems/unionfs/usage.txt | 31 + MAINTAINERS | 7 fs/Kconfig | 38 + fs/Makefile | 1 fs/namei.c | 8 fs/unionfs/Makefile | 7 fs/unionfs/branchman.c | 81 ++ fs/unionfs/commonfops.c | 593 +++++++++++++++ fs/unionfs/copyup.c | 761 +++++++++++++++++++ fs/unionfs/dentry.c | 238 ++++++ fs/unionfs/dirfops.c | 263 +++++++ fs/unionfs/dirhelper.c | 270 +++++++ fs/unionfs/fanout.h | 210 +++++ fs/unionfs/file.c | 252 ++++++ fs/unionfs/inode.c | 956 ++++++++++++++++++++++++ fs/unionfs/lookup.c | 515 +++++++++++++ fs/unionfs/main.c | 687 +++++++++++++++++ fs/unionfs/rdstate.c | 281 +++++++ fs/unionfs/rename.c | 445 +++++++++++ fs/unionfs/sioq.c | 123 +++ fs/unionfs/sioq.h | 78 ++ fs/unionfs/subr.c | 233 ++++++ fs/unionfs/super.c | 345 +++++++++ fs/unionfs/union.h | 439 +++++++++++ fs/unionfs/unlink.c | 162 ++++ fs/unionfs/xattr.c | 123 +++ include/linux/magic.h | 2 include/linux/namei.h | 10 include/linux/union_fs.h | 18 34 files changed, 7308 insertions(+), 5 deletions(-) diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX index 4dc28cc..c737e3e 100644 --- a/Documentation/filesystems/00-INDEX +++ b/Documentation/filesystems/00-INDEX @@ -82,6 +82,8 @@ udf.txt - info and mount options for the UDF filesystem. ufs.txt - info on the ufs filesystem. +unionfs/ + - info on the unionfs filesystem v9fs.txt - v9fs is a Unix implementation of the Plan 9 9p remote fs protocol. vfat.txt diff --git a/Documentation/filesystems/unionfs/00-INDEX b/Documentation/filesystems/unionfs/00-INDEX new file mode 100644 index 0000000..96fdf67 --- /dev/null +++ b/Documentation/filesystems/unionfs/00-INDEX @@ -0,0 +1,10 @@ +00-INDEX + - this file. +concepts.txt + - A brief introduction of concepts. +issues.txt + - A summary of known issues with unionfs. +rename.txt + - Information regarding rename operations. +usage.txt + - Usage information and examples. diff --git a/Documentation/filesystems/unionfs/concepts.txt b/Documentation/filesystems/unionfs/concepts.txt new file mode 100644 index 0000000..d417576 --- /dev/null +++ b/Documentation/filesystems/unionfs/concepts.txt @@ -0,0 +1,70 @@ +This file describes the concepts needed by a namespace unification file +system. + +Branch Priority: +================ + +Each branch is assigned a unique priority - starting from 0 (highest +priority). No two branches can have the same priority. + + +Branch Mode: +============ + +Each branch is assigned a mode - read-write or read-only. This allows +directories on media mounted read-write to be used in a read-only manner. + + +Whiteouts: +========== + +A whiteout removes a file name from the namespace. Whiteouts are needed when +one attempts to remove a file on a read-only branch. + +Suppose we have a two-branch union, where branch 0 is read-write and branch +1 is read-only. And a file 'foo' on branch 1: + +./b0/ +./b1/ +./b1/foo + +The unified view would simply be: + +./union/ +./union/foo + +Since 'foo' is stored on a read-only branch, it cannot be removed. A +whiteout is used to remove the name 'foo' from the unified namespace. Again, +since branch 1 is read-only, the whiteout cannot be created there. So, we +try on a higher priority (lower numerically) branch and create the whiteout +there. + +./b0/ +./b0/.wh.foo +./b1/ +./b1/foo + +Later, when Unionfs traverses branches (due to lookup or readdir), it +eliminate 'foo' from the namespace (as well as the whiteout itself.) + + +Duplicate Elimination: +====================== + +It is possible for files on different branches to have the same name. +Unionfs then has to select which instance of the file to show to the user. +Given the fact that each branch has a priority associated with it, the +simplest solution is to take the instance from the highest priority +(numerically lowest value) and "hide" the others. + + +Copyup: +======= + +When a change is made to the contents of a file's data or meta-data, they +have to be stored somewhere. The best way is to create a copy of the +original file on a branch that is writable, and then redirect the write +though to this copy. The copy must be made on a higher priority branch so +that lookup and readdir return this newer "version" of the file rather than +the original (see duplicate elimination). + diff --git a/Documentation/filesystems/unionfs/issues.txt b/Documentation/filesystems/unionfs/issues.txt new file mode 100644 index 0000000..b070175 --- /dev/null +++ b/Documentation/filesystems/unionfs/issues.txt @@ -0,0 +1,23 @@ +KNOWN Unionfs ISSUES: +===================== + +1. The NFS server returns -EACCES for read-only exports, instead of -EROFS. + This means we can't reliably detect a read-only NFS export. + +2. Modifying a Unionfs branch directly, while the union is mounted, is + currently unsupported. We have tested Unionfs under such conditions, and + fixed any bugs we found (Unionfs comes with an extensive regression test + suite). However, it may still be possible that changes made to lower + branches directly could cause cache incoherency which, in the worst case, + may case an oops. We are currently addressing this problem for Unionfs + and also generically for all stackable file systems, by handing mmap and + introducing small VFS/MM changes that would allow a file system to handle + cache coherency correctly. + +3. Unionfs should not use lookup_one_len() on the underlying f/s as it + confuses NFS. Currently, unionfs_lookup() passes lookup intents to the + lower file-system, this eliminates part of the problem. The remaining + calls to lookup_one_len may need to be changed to pass an intent. + + +For more information, see . diff --git a/Documentation/filesystems/unionfs/rename.txt b/Documentation/filesystems/unionfs/rename.txt new file mode 100644 index 0000000..e20bb82 --- /dev/null +++ b/Documentation/filesystems/unionfs/rename.txt @@ -0,0 +1,31 @@ +Rename is a complex beast. The following table shows which rename(2) operations +should succeed and which should fail. + +o: success +E: error (either unionfs or vfs) +X: EXDEV + +none = file does not exist +file = file is a file +dir = file is a empty directory +child= file is a non-empty directory +wh = file is a directory containing only whiteouts; this makes it logically + empty + + none file dir child wh +file o o E E E +dir o E o E o +child X E X E X +wh o E o E o + + +Renaming directories: +===================== + +Whenever a empty (either physically or logically) directory is being renamed, +the following sequence of events should take place: + +1) Remove whiteouts from both source and destination directory +2) Rename source to destination +3) Make destination opaque to prevent anything under it from showing up + diff --git a/Documentation/filesystems/unionfs/usage.txt b/Documentation/filesystems/unionfs/usage.txt new file mode 100644 index 0000000..14e0856 --- /dev/null +++ b/Documentation/filesystems/unionfs/usage.txt @@ -0,0 +1,31 @@ +Unionfs is a stackable unification file system, which can appear to merge +the contents of several directories (branches), while keeping their physical +content separate. Unionfs is useful for unified source tree management, +merged contents of split CD-ROM, merged separate software package +directories, data grids, and more. Unionfs allows any mix of read-only and +read-write branches, as well as insertion and deletion of branches anywhere +in the fan-out. To maintain Unix semantics, Unionfs handles elimination of +duplicates, partial-error conditions, and more. + +# mount -t unionfs -o branch-option[,union-options[,...]] none MOUNTPOINT + +The available branch-option for the mount command is: + + dirs=branch[=ro|=rw][:...] + +specifies a separated list of which directories compose the union. +Directories that come earlier in the list have a higher precedence than +those which come later. Additionally, read-only or read-write permissions of +the branch can be specified by appending =ro or =rw (default) to each +directory. + +Syntax: + + dirs=/branch1[=ro|=rw]:/branch2[=ro|=rw]:...:/branchN[=ro|=rw] + +Example: + + dirs=/writable_branch=rw:/read-only_branch=ro + + +For more information, see unionfs.filesystems.org. diff --git a/MAINTAINERS b/MAINTAINERS index 9e6c9ff..63290c6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3350,6 +3350,13 @@ L: linux-kernel@vger.kernel.org W: http://www.kernel.dk S: Maintained +UNIONFS +P: Josef "Jeff" Sipek +M: jsipek@cs.sunysb.edu +L: unionfs@filesystems.org +W: http://www.unionfs.org +S: Maintained + USB ACM DRIVER P: Oliver Neukum M: oliver@neukum.name diff --git a/fs/Kconfig b/fs/Kconfig index a722b5a..3637e6b 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -1034,6 +1034,41 @@ config CONFIGFS_FS endmenu +menu "Layered filesystems" + +config ECRYPT_FS + tristate "eCrypt filesystem layer support (EXPERIMENTAL)" + depends on EXPERIMENTAL && KEYS && CRYPTO + help + Encrypted filesystem that operates on the VFS layer. See + to learn more about + eCryptfs. Userspace components are required and can be + obtained from . + + To compile this file system support as a module, choose M here: the + module will be called ecryptfs. + +config UNION_FS + tristate "Union file system (EXPERIMENTAL)" + depends on EXPERIMENTAL + help + Unionfs is a stackable unification file system, which appears to + merge the contents of several directories (branches), while keeping + their physical content separate. + + See for details + +config UNION_FS_XATTR + bool "Unionfs extended attributes" + depends on UNION_FS + help + Extended attributes are name:value pairs associated with inodes by + the kernel or by users (see the attr(5) manual page). + + If unsure, say N. + +endmenu + menu "Miscellaneous filesystems" config ADFS_FS @@ -1086,6 +1121,7 @@ config AFFS_FS To compile this file system support as a module, choose M here: the module will be called affs. If unsure, say N. +<<<<<<< HEAD/fs/Kconfig config ECRYPT_FS tristate "eCrypt filesystem layer support (EXPERIMENTAL)" depends on EXPERIMENTAL && KEYS && CRYPTO && NET @@ -1098,6 +1134,8 @@ config ECRYPT_FS To compile this file system support as a module, choose M here: the module will be called ecryptfs. +======= +>>>>>>> /fs/Kconfig config HFS_FS tristate "Apple Macintosh file system support (EXPERIMENTAL)" depends on BLOCK && EXPERIMENTAL diff --git a/fs/Makefile b/fs/Makefile index b9ffa63..76c6acc 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -115,3 +115,4 @@ obj-$(CONFIG_HPPFS) += hppfs/ obj-$(CONFIG_DEBUG_FS) += debugfs/ obj-$(CONFIG_OCFS2_FS) += ocfs2/ obj-$(CONFIG_GFS2_FS) += gfs2/ +obj-$(CONFIG_UNION_FS) += unionfs/ diff --git a/fs/namei.c b/fs/namei.c index 161e222..6d08a4c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1292,8 +1292,8 @@ static struct dentry *lookup_hash(struct return __lookup_hash(&nd->last, nd->dentry, nd); } -/* SMP-safe */ -struct dentry * lookup_one_len(const char * name, struct dentry * base, int len) +struct dentry *lookup_one_len_nd(const char *name, struct dentry *base, + int len, struct nameidata *nd) { unsigned long hash; struct qstr this; @@ -1313,7 +1313,7 @@ struct dentry * lookup_one_len(const cha } this.hash = end_name_hash(hash); - return __lookup_hash(&this, base, NULL); + return __lookup_hash(&this, base, nd); access: return ERR_PTR(-EACCES); } @@ -2757,7 +2757,7 @@ EXPORT_SYMBOL(follow_up); EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ EXPORT_SYMBOL(getname); EXPORT_SYMBOL(lock_rename); -EXPORT_SYMBOL(lookup_one_len); +EXPORT_SYMBOL(lookup_one_len_nd); EXPORT_SYMBOL(page_follow_link_light); EXPORT_SYMBOL(page_put_link); EXPORT_SYMBOL(page_readlink); diff --git a/fs/unionfs/Makefile b/fs/unionfs/Makefile new file mode 100644 index 0000000..e6b2e0c --- /dev/null +++ b/fs/unionfs/Makefile @@ -0,0 +1,7 @@ +obj-$(CONFIG_UNION_FS) += unionfs.o + +unionfs-y := subr.o dentry.o file.o inode.o main.o super.o \ + branchman.o rdstate.o copyup.o dirhelper.o rename.o \ + unlink.o lookup.o commonfops.o dirfops.o sioq.o + +unionfs-$(CONFIG_UNION_FS_XATTR) += xattr.o diff --git a/fs/unionfs/branchman.c b/fs/unionfs/branchman.c new file mode 100644 index 0000000..83d443a --- /dev/null +++ b/fs/unionfs/branchman.c @@ -0,0 +1,81 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* increase the superblock generation count; effectively invalidating every + * upper inode, dentry and file object */ +int unionfs_ioctl_incgen(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct super_block *sb; + int gen; + + sb = file->f_dentry->d_sb; + + unionfs_write_lock(sb); + + gen = atomic_inc_return(&UNIONFS_SB(sb)->generation); + + atomic_set(&UNIONFS_D(sb->s_root)->generation, gen); + atomic_set(&UNIONFS_I(sb->s_root->d_inode)->generation, gen); + + unionfs_write_unlock(sb); + + return gen; +} + +/* return to userspace the branch indices containing the file in question + * + * We use fd_set and therefore we are limited to the number of the branches + * to FD_SETSIZE, which is currently 1024 - plenty for most people + */ +int unionfs_ioctl_queryfile(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int err = 0; + fd_set branchlist; + + int bstart = 0, bend = 0, bindex = 0; + struct dentry *dentry, *hidden_dentry; + + dentry = file->f_dentry; + unionfs_lock_dentry(dentry); + if ((err = unionfs_partial_lookup(dentry))) + goto out; + bstart = dbstart(dentry); + bend = dbend(dentry); + + FD_ZERO(&branchlist); + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) + continue; + if (hidden_dentry->d_inode) + FD_SET(bindex, &branchlist); + } + + err = copy_to_user((void __user *)arg, &branchlist, sizeof(fd_set)); + if (err) + err = -EFAULT; + +out: + unionfs_unlock_dentry(dentry); + return err < 0 ? err : bend; +} + diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c new file mode 100644 index 0000000..379c525 --- /dev/null +++ b/fs/unionfs/commonfops.c @@ -0,0 +1,593 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* 1) Copyup the file + * 2) Rename the file to '.unionfs' - obviously + * stolen from NFS's silly rename + */ +static int copyup_deleted_file(struct file *file, struct dentry *dentry, + int bstart, int bindex) +{ + static unsigned int counter; + const int i_inosize = sizeof(dentry->d_inode->i_ino) * 2; + const int countersize = sizeof(counter) * 2; + const int nlen = sizeof(".unionfs") + i_inosize + countersize - 1; + char name[nlen + 1]; + + int err; + struct dentry *tmp_dentry = NULL; + struct dentry *hidden_dentry; + struct dentry *hidden_dir_dentry = NULL; + + hidden_dentry = unionfs_lower_dentry_idx(dentry, bstart); + + sprintf(name, ".unionfs%*.*lx", + i_inosize, i_inosize, hidden_dentry->d_inode->i_ino); + + tmp_dentry = NULL; + do { + char *suffix = name + nlen - countersize; + + dput(tmp_dentry); + counter++; + sprintf(suffix, "%*.*x", countersize, countersize, counter); + + printk(KERN_DEBUG "unionfs: trying to rename %s to %s\n", + dentry->d_name.name, name); + + tmp_dentry = lookup_one_len(name, hidden_dentry->d_parent, + UNIONFS_TMPNAM_LEN); + if (IS_ERR(tmp_dentry)) { + err = PTR_ERR(tmp_dentry); + goto out; + } + } while (tmp_dentry->d_inode != NULL); /* need negative dentry */ + + err = copyup_named_file(dentry->d_parent->d_inode, file, name, bstart, + bindex, file->f_dentry->d_inode->i_size); + if (err) + goto out; + + /* bring it to the same state as an unlinked file */ + hidden_dentry = unionfs_lower_dentry_idx(dentry, dbstart(dentry)); + hidden_dir_dentry = lock_parent(hidden_dentry); + err = vfs_unlink(hidden_dir_dentry->d_inode, hidden_dentry); + unlock_dir(hidden_dir_dentry); + +out: + return err; +} + +/* put all references held by upper struct file and free lower file pointer + * array + */ +static void cleanup_file(struct file *file) +{ + int bindex, bstart, bend; + struct file **lf; + + lf = UNIONFS_F(file)->lower_files; + bstart = fbstart(file); + bend = fbend(file); + + for (bindex = bstart; bindex <= bend; bindex++) { + if (unionfs_lower_file_idx(file, bindex)) { + branchput(file->f_dentry->d_sb, bindex); + fput(unionfs_lower_file_idx(file, bindex)); + } + } + + UNIONFS_F(file)->lower_files = NULL; + kfree(lf); +} + +/* open all lower files for a given file */ +static int open_all_files(struct file *file) +{ + int bindex, bstart, bend, err = 0; + struct file *hidden_file; + struct dentry *hidden_dentry; + struct dentry *dentry = file->f_dentry; + struct super_block *sb = dentry->d_sb; + + bstart = dbstart(dentry); + bend = dbend(dentry); + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) + continue; + + dget(hidden_dentry); + mntget(unionfs_lower_mnt_idx(dentry, bindex)); + branchget(sb, bindex); + + hidden_file = dentry_open(hidden_dentry, + unionfs_lower_mnt_idx(dentry, bindex), + file->f_flags); + if (IS_ERR(hidden_file)) { + err = PTR_ERR(hidden_file); + goto out; + } else + unionfs_set_lower_file_idx(file, bindex, hidden_file); + } +out: + return err; +} + +/* open the highest priority file for a given upper file */ +static int open_highest_file(struct file *file, int willwrite) +{ + int bindex, bstart, bend, err = 0; + struct file *hidden_file; + struct dentry *hidden_dentry; + + struct dentry *dentry = file->f_dentry; + struct inode *parent_inode = dentry->d_parent->d_inode; + struct super_block *sb = dentry->d_sb; + size_t inode_size = dentry->d_inode->i_size; + + bstart = dbstart(dentry); + bend = dbend(dentry); + + hidden_dentry = unionfs_lower_dentry(dentry); + if (willwrite && IS_WRITE_FLAG(file->f_flags) && is_robranch(dentry)) { + for (bindex = bstart - 1; bindex >= 0; bindex--) { + err = copyup_file(parent_inode, file, bstart, bindex, + inode_size); + if (!err) + break; + } + atomic_set(&UNIONFS_F(file)->generation, + atomic_read(&UNIONFS_I(dentry->d_inode)->generation)); + goto out; + } + + dget(hidden_dentry); + mntget(unionfs_lower_mnt_idx(dentry, bstart)); + branchget(sb, bstart); + hidden_file = dentry_open(hidden_dentry, + unionfs_lower_mnt_idx(dentry, bstart), file->f_flags); + if (IS_ERR(hidden_file)) { + err = PTR_ERR(hidden_file); + goto out; + } + unionfs_set_lower_file(file, hidden_file); + /* Fix up the position. */ + hidden_file->f_pos = file->f_pos; + + memcpy(&hidden_file->f_ra, &file->f_ra, sizeof(struct file_ra_state)); +out: + return err; +} + +static int do_delayed_copyup(struct file *file, struct dentry *dentry) +{ + int bindex, bstart, bend, err = 0; + struct inode *parent_inode = dentry->d_parent->d_inode; + loff_t inode_size = file->f_dentry->d_inode->i_size; + + bstart = fbstart(file); + bend = fbend(file); + + BUG_ON(!S_ISREG(file->f_dentry->d_inode->i_mode)); + + for (bindex = bstart - 1; bindex >= 0; bindex--) { + if (!d_deleted(file->f_dentry)) + err = copyup_file(parent_inode, file, bstart, + bindex, inode_size); + else + err = copyup_deleted_file(file, dentry, bstart, bindex); + + if (!err) + break; + } + if (!err && (bstart > fbstart(file))) { + bend = fbend(file); + for (bindex = bstart; bindex <= bend; bindex++) { + if (unionfs_lower_file_idx(file, bindex)) { + branchput(dentry->d_sb, bindex); + fput(unionfs_lower_file_idx(file, bindex)); + unionfs_set_lower_file_idx(file, bindex, NULL); + } + } + fbend(file) = bend; + } + return err; +} + +/* revalidate the stuct file */ +int unionfs_file_revalidate(struct file *file, int willwrite) +{ + struct super_block *sb; + struct dentry *dentry; + int sbgen, fgen, dgen; + int bstart, bend; + int size; + + int err = 0; + + dentry = file->f_dentry; + unionfs_lock_dentry(dentry); + sb = dentry->d_sb; + unionfs_read_lock(sb); + if (!unionfs_d_revalidate(dentry, NULL) && !d_deleted(dentry)) { + err = -ESTALE; + goto out; + } + + sbgen = atomic_read(&UNIONFS_SB(sb)->generation); + dgen = atomic_read(&UNIONFS_D(dentry)->generation); + fgen = atomic_read(&UNIONFS_F(file)->generation); + + BUG_ON(sbgen > dgen); + + /* There are two cases we are interested in. The first is if the + * generation is lower than the super-block. The second is if someone + * has copied up this file from underneath us, we also need to refresh + * things. + */ + if (!d_deleted(dentry) && + (sbgen > fgen || dbstart(dentry) != fbstart(file))) { + /* First we throw out the existing files. */ + cleanup_file(file); + + /* Now we reopen the file(s) as in unionfs_open. */ + bstart = fbstart(file) = dbstart(dentry); + bend = fbend(file) = dbend(dentry); + + size = sizeof(struct file *) * sbmax(sb); + UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL); + if (!UNIONFS_F(file)->lower_files) { + err = -ENOMEM; + goto out; + } + + if (S_ISDIR(dentry->d_inode->i_mode)) { + /* We need to open all the files. */ + err = open_all_files(file); + if (err) + goto out; + } else { + /* We only open the highest priority branch. */ + err = open_highest_file(file, willwrite); + if (err) + goto out; + } + atomic_set(&UNIONFS_F(file)->generation, + atomic_read(&UNIONFS_I(dentry->d_inode)-> + generation)); + } + + /* Copyup on the first write to a file on a readonly branch. */ + if (willwrite && IS_WRITE_FLAG(file->f_flags) && + !IS_WRITE_FLAG(unionfs_lower_file(file)->f_flags) && + is_robranch(dentry)) { + printk(KERN_DEBUG "Doing delayed copyup of a read-write " + "file on a read-only branch.\n"); + err = do_delayed_copyup(file, dentry); + } + +out: + unionfs_unlock_dentry(dentry); + unionfs_read_unlock(dentry->d_sb); + return err; +} + +/* unionfs_open helper function: open a directory */ +static int __open_dir(struct inode *inode, struct file *file) +{ + struct dentry *hidden_dentry; + struct file *hidden_file; + int bindex, bstart, bend; + + bstart = fbstart(file) = dbstart(file->f_dentry); + bend = fbend(file) = dbend(file->f_dentry); + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(file->f_dentry, bindex); + if (!hidden_dentry) + continue; + + dget(hidden_dentry); + mntget(unionfs_lower_mnt_idx(file->f_dentry, bindex)); + hidden_file = dentry_open(hidden_dentry, + unionfs_lower_mnt_idx(file->f_dentry, bindex), + file->f_flags); + if (IS_ERR(hidden_file)) + return PTR_ERR(hidden_file); + + unionfs_set_lower_file_idx(file, bindex, hidden_file); + + /* The branchget goes after the open, because otherwise + * we would miss the reference on release. + */ + branchget(inode->i_sb, bindex); + } + + return 0; +} + +/* unionfs_open helper function: open a file */ +static int __open_file(struct inode *inode, struct file *file) +{ + struct dentry *hidden_dentry; + struct file *hidden_file; + int hidden_flags; + int bindex, bstart, bend; + + hidden_dentry = unionfs_lower_dentry(file->f_dentry); + hidden_flags = file->f_flags; + + bstart = fbstart(file) = dbstart(file->f_dentry); + bend = fbend(file) = dbend(file->f_dentry); + + /* check for the permission for hidden file. If the error is COPYUP_ERR, + * copyup the file. + */ + if (hidden_dentry->d_inode && is_robranch(file->f_dentry)) { + /* if the open will change the file, copy it up otherwise + * defer it. + */ + if (hidden_flags & O_TRUNC) { + int size = 0; + int err = -EROFS; + + /* copyup the file */ + for (bindex = bstart - 1; bindex >= 0; bindex--) { + err = copyup_file(file->f_dentry->d_parent->d_inode, + file, bstart, bindex, size); + if (!err) + break; + } + return err; + } else + hidden_flags &= ~(OPEN_WRITE_FLAGS); + } + + dget(hidden_dentry); + + /* dentry_open will decrement mnt refcnt if err. + * otherwise fput() will do an mntput() for us upon file close. + */ + mntget(unionfs_lower_mnt_idx(file->f_dentry, bstart)); + hidden_file = dentry_open(hidden_dentry, + unionfs_lower_mnt_idx(file->f_dentry, bstart), + hidden_flags); + if (IS_ERR(hidden_file)) + return PTR_ERR(hidden_file); + + unionfs_set_lower_file(file, hidden_file); + branchget(inode->i_sb, bstart); + + return 0; +} + +int unionfs_open(struct inode *inode, struct file *file) +{ + int err = 0; + struct file *hidden_file = NULL; + struct dentry *dentry = NULL; + int bindex = 0, bstart = 0, bend = 0; + int size; + + file->private_data = kzalloc(sizeof(struct unionfs_file_info), GFP_KERNEL); + if (!UNIONFS_F(file)) { + err = -ENOMEM; + goto out; + } + fbstart(file) = -1; + fbend(file) = -1; + atomic_set(&UNIONFS_F(file)->generation, + atomic_read(&UNIONFS_I(inode)->generation)); + + size = sizeof(struct file *) * sbmax(inode->i_sb); + UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL); + if (!UNIONFS_F(file)->lower_files) { + err = -ENOMEM; + goto out; + } + + dentry = file->f_dentry; + unionfs_lock_dentry(dentry); + unionfs_read_lock(inode->i_sb); + + bstart = fbstart(file) = dbstart(dentry); + bend = fbend(file) = dbend(dentry); + + /* increment, so that we can flush appropriately */ + atomic_inc(&UNIONFS_I(dentry->d_inode)->totalopens); + + /* open all directories and make the unionfs file struct point to + * these hidden file structs + */ + if (S_ISDIR(inode->i_mode)) + err = __open_dir(inode, file); /* open a dir */ + else + err = __open_file(inode, file); /* open a file */ + + /* freeing the allocated resources, and fput the opened files */ + if (err) { + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_file = unionfs_lower_file_idx(file, bindex); + if (!hidden_file) + continue; + + branchput(file->f_dentry->d_sb, bindex); + /* fput calls dput for hidden_dentry */ + fput(hidden_file); + } + } + + unionfs_unlock_dentry(dentry); + unionfs_read_unlock(inode->i_sb); + +out: + if (err) { + kfree(UNIONFS_F(file)->lower_files); + kfree(UNIONFS_F(file)); + } + + return err; +} + +/* release all lower object references & free the file info structure */ +int unionfs_file_release(struct inode *inode, struct file *file) +{ + struct file *hidden_file = NULL; + struct unionfs_file_info *fileinfo = UNIONFS_F(file); + struct unionfs_inode_info *inodeinfo = UNIONFS_I(inode); + int bindex, bstart, bend; + int fgen; + + /* fput all the hidden files */ + fgen = atomic_read(&fileinfo->generation); + bstart = fbstart(file); + bend = fbend(file); + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_file = unionfs_lower_file_idx(file, bindex); + + if (hidden_file) { + fput(hidden_file); + unionfs_read_lock(inode->i_sb); + branchput(inode->i_sb, bindex); + unionfs_read_unlock(inode->i_sb); + } + } + kfree(fileinfo->lower_files); + + if (fileinfo->rdstate) { + fileinfo->rdstate->access = jiffies; + printk(KERN_DEBUG "Saving rdstate with cookie %u [%d.%lld]\n", + fileinfo->rdstate->cookie, + fileinfo->rdstate->bindex, + (long long)fileinfo->rdstate->dirpos); + spin_lock(&inodeinfo->rdlock); + inodeinfo->rdcount++; + list_add_tail(&fileinfo->rdstate->cache, + &inodeinfo->readdircache); + mark_inode_dirty(inode); + spin_unlock(&inodeinfo->rdlock); + fileinfo->rdstate = NULL; + } + kfree(fileinfo); + return 0; +} + +/* pass the ioctl to the lower fs */ +static long do_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct file *hidden_file; + int err; + + hidden_file = unionfs_lower_file(file); + + err = security_file_ioctl(hidden_file, cmd, arg); + if (err) + goto out; + + err = -ENOTTY; + if (!hidden_file || !hidden_file->f_op) + goto out; + if (hidden_file->f_op->unlocked_ioctl) { + err = hidden_file->f_op->unlocked_ioctl(hidden_file, cmd, arg); + } else if (hidden_file->f_op->ioctl) { + lock_kernel(); + err = hidden_file->f_op->ioctl(hidden_file->f_dentry->d_inode, + hidden_file, cmd, arg); + unlock_kernel(); + } + +out: + return err; +} + +long unionfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + long err; + + if ((err = unionfs_file_revalidate(file, 1))) + goto out; + + /* check if asked for local commands */ + switch (cmd) { + case UNIONFS_IOCTL_INCGEN: + /* Increment the superblock generation count */ + err = -EACCES; + if (!capable(CAP_SYS_ADMIN)) + goto out; + err = unionfs_ioctl_incgen(file, cmd, arg); + break; + + case UNIONFS_IOCTL_QUERYFILE: + /* Return list of branches containing the given file */ + err = unionfs_ioctl_queryfile(file, cmd, arg); + break; + + default: + /* pass the ioctl down */ + err = do_ioctl(file, cmd, arg); + break; + } + +out: + return err; +} + +int unionfs_flush(struct file *file, fl_owner_t id) +{ + int err = 0; + struct file *hidden_file = NULL; + struct dentry *dentry = file->f_dentry; + int bindex, bstart, bend; + + if ((err = unionfs_file_revalidate(file, 1))) + goto out; + if (!atomic_dec_and_test(&UNIONFS_I(dentry->d_inode)->totalopens)) + goto out; + + unionfs_lock_dentry(dentry); + + bstart = fbstart(file); + bend = fbend(file); + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_file = unionfs_lower_file_idx(file, bindex); + + if (hidden_file && hidden_file->f_op && hidden_file->f_op->flush) { + err = hidden_file->f_op->flush(hidden_file, id); + if (err) + goto out_lock; + + /* if there are no more references to the dentry, dput it */ + if (d_deleted(dentry)) { + dput(unionfs_lower_dentry_idx(dentry, bindex)); + unionfs_set_lower_dentry_idx(dentry, bindex, NULL); + } + } + + } + +out_lock: + unionfs_unlock_dentry(dentry); +out: + return err; +} + diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c new file mode 100644 index 0000000..998cc69 --- /dev/null +++ b/fs/unionfs/copyup.c @@ -0,0 +1,761 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York* + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +static int copyup_named_dentry(struct inode *dir, struct dentry *dentry, + int bstart, int new_bindex, const char *name, + int namelen, struct file **copyup_file, + loff_t len); +static struct dentry *create_parents_named(struct inode *dir, + struct dentry *dentry, + const char *name, int bindex); + +/* For detailed explanation of copyup see: + * Documentation/filesystems/unionfs/concepts.txt + */ + +#ifdef CONFIG_UNION_FS_XATTR +/* copyup all extended attrs for a given dentry */ +static int copyup_xattrs(struct dentry *old_hidden_dentry, + struct dentry *new_hidden_dentry) +{ + int err = 0; + ssize_t list_size = -1; + char *name_list = NULL; + char *attr_value = NULL; + char *name_list_orig = NULL; + + list_size = vfs_listxattr(old_hidden_dentry, NULL, 0); + + if (list_size <= 0) { + err = list_size; + goto out; + } + + name_list = unionfs_xattr_alloc(list_size + 1, XATTR_LIST_MAX); + if (!name_list || IS_ERR(name_list)) { + err = PTR_ERR(name_list); + goto out; + } + list_size = vfs_listxattr(old_hidden_dentry, name_list, list_size); + attr_value = unionfs_xattr_alloc(XATTR_SIZE_MAX, XATTR_SIZE_MAX); + if (!attr_value || IS_ERR(attr_value)) { + err = PTR_ERR(name_list); + goto out; + } + name_list_orig = name_list; + while (*name_list) { + ssize_t size; + + /* Lock here since vfs_getxattr doesn't lock for us */ + mutex_lock(&old_hidden_dentry->d_inode->i_mutex); + size = vfs_getxattr(old_hidden_dentry, name_list, + attr_value, XATTR_SIZE_MAX); + mutex_unlock(&old_hidden_dentry->d_inode->i_mutex); + if (size < 0) { + err = size; + goto out; + } + + if (size > XATTR_SIZE_MAX) { + err = -E2BIG; + goto out; + } + /* Don't lock here since vfs_setxattr does it for us. */ + err = vfs_setxattr(new_hidden_dentry, name_list, attr_value, + size, 0); + + if (err < 0) + goto out; + name_list += strlen(name_list) + 1; + } + out: + name_list = name_list_orig; + + if (name_list) + unionfs_xattr_free(name_list, list_size + 1); + if (attr_value) + unionfs_xattr_free(attr_value, XATTR_SIZE_MAX); + /* It is no big deal if this fails, we just roll with the punches. */ + if (err == -ENOTSUPP || err == -EOPNOTSUPP) + err = 0; + return err; +} +#endif /* CONFIG_UNION_FS_XATTR */ + +/* Determine the mode based on the copyup flags, and the existing dentry. */ +static int copyup_permissions(struct super_block *sb, + struct dentry *old_hidden_dentry, + struct dentry *new_hidden_dentry) +{ + struct inode *i = old_hidden_dentry->d_inode; + struct iattr newattrs; + int err; + + newattrs.ia_atime = i->i_atime; + newattrs.ia_mtime = i->i_mtime; + newattrs.ia_ctime = i->i_ctime; + + newattrs.ia_gid = i->i_gid; + newattrs.ia_uid = i->i_uid; + + newattrs.ia_mode = i->i_mode; + + newattrs.ia_valid = ATTR_CTIME | ATTR_ATIME | ATTR_MTIME | + ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_FORCE | + ATTR_GID | ATTR_UID | ATTR_MODE; + + err = notify_change(new_hidden_dentry, &newattrs); + + return err; +} + +int copyup_dentry(struct inode *dir, struct dentry *dentry, + int bstart, int new_bindex, + struct file **copyup_file, loff_t len) +{ + return copyup_named_dentry(dir, dentry, bstart, new_bindex, + dentry->d_name.name, + dentry->d_name.len, copyup_file, len); +} + +/* create the new device/file/directory - use copyup_permission to copyup + * times, and mode + * + * if the object being copied up is a regular file, the file is only created, + * the contents have to be copied up separately + */ +static int __copyup_ndentry(struct dentry *old_hidden_dentry, + struct dentry *new_hidden_dentry, + struct dentry *new_hidden_parent_dentry, + char *symbuf) +{ + int err = 0; + umode_t old_mode = old_hidden_dentry->d_inode->i_mode; + struct sioq_args args; + + if (S_ISDIR(old_mode)) { + args.mkdir.parent = new_hidden_parent_dentry->d_inode; + args.mkdir.dentry = new_hidden_dentry; + args.mkdir.mode = old_mode; + + run_sioq(__unionfs_mkdir, &args); + err = args.err; + } else if (S_ISLNK(old_mode)) { + args.symlink.parent = new_hidden_parent_dentry->d_inode; + args.symlink.dentry = new_hidden_dentry; + args.symlink.symbuf = symbuf; + args.symlink.mode = old_mode; + + run_sioq(__unionfs_symlink, &args); + err = args.err; + } else if (S_ISBLK(old_mode) || S_ISCHR(old_mode) || + S_ISFIFO(old_mode) || S_ISSOCK(old_mode)) { + args.mknod.parent = new_hidden_parent_dentry->d_inode; + args.mknod.dentry = new_hidden_dentry; + args.mknod.mode = old_mode; + args.mknod.dev = old_hidden_dentry->d_inode->i_rdev; + + run_sioq(__unionfs_mknod, &args); + err = args.err; + } else if (S_ISREG(old_mode)) { + args.create.parent = new_hidden_parent_dentry->d_inode; + args.create.dentry = new_hidden_dentry; + args.create.mode = old_mode; + args.create.nd = NULL; + + run_sioq(__unionfs_create, &args); + err = args.err; + } else { + printk(KERN_ERR "Unknown inode type %d\n", + old_mode); + BUG(); + } + + return err; +} + +static int __copyup_reg_data(struct dentry *dentry, + struct dentry *new_hidden_dentry, int new_bindex, + struct dentry *old_hidden_dentry, int old_bindex, + struct file **copyup_file, loff_t len) +{ + struct super_block *sb = dentry->d_sb; + struct file *input_file; + struct file *output_file; + mm_segment_t old_fs; + char *buf = NULL; + ssize_t read_bytes, write_bytes; + loff_t size; + int err = 0; + + /* open old file */ + mntget(unionfs_lower_mnt_idx(dentry, old_bindex)); + branchget(sb, old_bindex); + input_file = dentry_open(old_hidden_dentry, + unionfs_lower_mnt_idx(dentry, old_bindex), + O_RDONLY | O_LARGEFILE); + if (IS_ERR(input_file)) { + dput(old_hidden_dentry); + err = PTR_ERR(input_file); + goto out; + } + if (!input_file->f_op || !input_file->f_op->read) { + err = -EINVAL; + goto out_close_in; + } + + /* open new file */ + dget(new_hidden_dentry); + mntget(unionfs_lower_mnt_idx(dentry, new_bindex)); + branchget(sb, new_bindex); + output_file = dentry_open(new_hidden_dentry, + unionfs_lower_mnt_idx(dentry, new_bindex), + O_WRONLY | O_LARGEFILE); + if (IS_ERR(output_file)) { + err = PTR_ERR(output_file); + goto out_close_in2; + } + if (!output_file->f_op || !output_file->f_op->write) { + err = -EINVAL; + goto out_close_out; + } + + /* allocating a buffer */ + buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto out_close_out; + } + + input_file->f_pos = 0; + output_file->f_pos = 0; + + old_fs = get_fs(); + set_fs(KERNEL_DS); + + size = len; + err = 0; + do { + if (len >= PAGE_SIZE) + size = PAGE_SIZE; + else if ((len < PAGE_SIZE) && (len > 0)) + size = len; + + len -= PAGE_SIZE; + + read_bytes = + input_file->f_op->read(input_file, + (char __user *)buf, size, + &input_file->f_pos); + if (read_bytes <= 0) { + err = read_bytes; + break; + } + + write_bytes = + output_file->f_op->write(output_file, + (char __user *)buf, + read_bytes, + &output_file->f_pos); + if ((write_bytes < 0) || (write_bytes < read_bytes)) { + err = write_bytes; + break; + } + } while ((read_bytes > 0) && (len > 0)); + + set_fs(old_fs); + + kfree(buf); + + if (err) + goto out_close_out; + if (copyup_file) { + *copyup_file = output_file; + goto out_close_in; + } + +out_close_out: + fput(output_file); + +out_close_in2: + branchput(sb, new_bindex); + +out_close_in: + fput(input_file); + +out: + branchput(sb, old_bindex); + + return err; +} + +/* dput the lower references for old and new dentry & clear a lower dentry + * pointer + */ +static void __clear(struct dentry *dentry, struct dentry *old_hidden_dentry, + int old_bstart, int old_bend, + struct dentry *new_hidden_dentry, int new_bindex) +{ + /* get rid of the hidden dentry and all its traces */ + unionfs_set_lower_dentry_idx(dentry, new_bindex, NULL); + set_dbstart(dentry, old_bstart); + set_dbend(dentry, old_bend); + + dput(new_hidden_dentry); + dput(old_hidden_dentry); +} + +/* copy up a dentry to a file of specified name */ +static int copyup_named_dentry(struct inode *dir, struct dentry *dentry, + int bstart, int new_bindex, const char *name, + int namelen, struct file **copyup_file, + loff_t len) +{ + struct dentry *new_hidden_dentry; + struct dentry *old_hidden_dentry = NULL; + struct super_block *sb; + int err = 0; + int old_bindex; + int old_bstart; + int old_bend; + struct dentry *new_hidden_parent_dentry = NULL; + mm_segment_t oldfs; + char *symbuf = NULL; + + verify_locked(dentry); + + old_bindex = bstart; + old_bstart = dbstart(dentry); + old_bend = dbend(dentry); + + BUG_ON(new_bindex < 0); + BUG_ON(new_bindex >= old_bindex); + + sb = dir->i_sb; + + unionfs_read_lock(sb); + + if ((err = is_robranch_super(sb, new_bindex))) { + dput(old_hidden_dentry); + goto out; + } + + /* Create the directory structure above this dentry. */ + new_hidden_dentry = create_parents_named(dir, dentry, name, new_bindex); + if (IS_ERR(new_hidden_dentry)) { + dput(old_hidden_dentry); + err = PTR_ERR(new_hidden_dentry); + goto out; + } + + old_hidden_dentry = unionfs_lower_dentry_idx(dentry, old_bindex); + dget(old_hidden_dentry); + + /* For symlinks, we must read the link before we lock the directory. */ + if (S_ISLNK(old_hidden_dentry->d_inode->i_mode)) { + + symbuf = kmalloc(PATH_MAX, GFP_KERNEL); + if (!symbuf) { + __clear(dentry, old_hidden_dentry, + old_bstart, old_bend, + new_hidden_dentry, new_bindex); + err = -ENOMEM; + goto out_free; + } + + oldfs = get_fs(); + set_fs(KERNEL_DS); + err = old_hidden_dentry->d_inode->i_op->readlink( + old_hidden_dentry, + (char __user *)symbuf, + PATH_MAX); + set_fs(oldfs); + if (err) { + __clear(dentry, old_hidden_dentry, + old_bstart, old_bend, + new_hidden_dentry, new_bindex); + goto out_free; + } + symbuf[err] = '\0'; + } + + /* Now we lock the parent, and create the object in the new branch. */ + new_hidden_parent_dentry = lock_parent(new_hidden_dentry); + + /* create the new inode */ + err = __copyup_ndentry(old_hidden_dentry, new_hidden_dentry, + new_hidden_parent_dentry, symbuf); + + if (err) { + __clear(dentry, old_hidden_dentry, + old_bstart, old_bend, + new_hidden_dentry, new_bindex); + goto out_unlock; + } + + /* We actually copyup the file here. */ + if (S_ISREG(old_hidden_dentry->d_inode->i_mode)) + err = __copyup_reg_data(dentry, new_hidden_dentry, new_bindex, + old_hidden_dentry, old_bindex, copyup_file, len); + if (err) + goto out_unlink; + + /* Set permissions. */ + if ((err = copyup_permissions(sb, old_hidden_dentry, new_hidden_dentry))) + goto out_unlink; + +#ifdef CONFIG_UNION_FS_XATTR + /* Selinux uses extended attributes for permissions. */ + if ((err = copyup_xattrs(old_hidden_dentry, new_hidden_dentry))) + goto out_unlink; +#endif + + /* do not allow files getting deleted to be reinterposed */ + if (!d_deleted(dentry)) + unionfs_reinterpose(dentry); + + goto out_unlock; + /****/ + +out_unlink: + /* copyup failed, because we possibly ran out of space or + * quota, or something else happened so let's unlink; we don't + * really care about the return value of vfs_unlink + */ + vfs_unlink(new_hidden_parent_dentry->d_inode, new_hidden_dentry); + + if (copyup_file) { + /* need to close the file */ + + fput(*copyup_file); + branchput(sb, new_bindex); + } + + /* + * TODO: should we reset the error to something like -EIO? + * + * If we don't reset, the user may get some non-sensical errors, but + * on the other hand, if we reset to EIO, we guarantee that the user + * will get a "confusing" error message. + */ + +out_unlock: + unlock_dir(new_hidden_parent_dentry); + +out_free: + kfree(symbuf); + +out: + unionfs_read_unlock(sb); + + return err; +} + +/* This function creates a copy of a file represented by 'file' which currently + * resides in branch 'bstart' to branch 'new_bindex.' The copy will be named + * "name". + */ +int copyup_named_file(struct inode *dir, struct file *file, char *name, + int bstart, int new_bindex, loff_t len) +{ + int err = 0; + struct file *output_file = NULL; + + err = copyup_named_dentry(dir, file->f_dentry, bstart, + new_bindex, name, strlen(name), &output_file, + len); + if (!err) { + fbstart(file) = new_bindex; + unionfs_set_lower_file_idx(file, new_bindex, output_file); + } + + return err; +} + +/* This function creates a copy of a file represented by 'file' which currently + * resides in branch 'bstart' to branch 'new_bindex'. + */ +int copyup_file(struct inode *dir, struct file *file, int bstart, + int new_bindex, loff_t len) +{ + int err = 0; + struct file *output_file = NULL; + + err = copyup_dentry(dir, file->f_dentry, bstart, new_bindex, + &output_file, len); + if (!err) { + fbstart(file) = new_bindex; + unionfs_set_lower_file_idx(file, new_bindex, output_file); + } + + return err; +} + +/* This function replicates the directory structure upto given dentry + * in the bindex branch. Can create directory structure recursively to the right + * also. + */ +struct dentry *create_parents(struct inode *dir, struct dentry *dentry, + int bindex) +{ + return create_parents_named(dir, dentry, dentry->d_name.name, bindex); +} + +static void __cleanup_dentry(struct dentry * dentry, int bindex, + int old_bstart, int old_bend) +{ + int loop_start; + int loop_end; + int new_bstart = -1; + int new_bend = -1; + int i; + + loop_start = min(old_bstart, bindex); + loop_end = max(old_bend, bindex); + + /* This loop sets the bstart and bend for the new dentry by + * traversing from left to right. It also dputs all negative + * dentries except bindex + */ + for (i = loop_start; i <= loop_end; i++) { + if (!unionfs_lower_dentry_idx(dentry, i)) + continue; + + if (i == bindex) { + new_bend = i; + if (new_bstart < 0) + new_bstart = i; + continue; + } + + if (!unionfs_lower_dentry_idx(dentry, i)->d_inode) { + dput(unionfs_lower_dentry_idx(dentry, i)); + unionfs_set_lower_dentry_idx(dentry, i, NULL); + } else { + if (new_bstart < 0) + new_bstart = i; + new_bend = i; + } + } + + if (new_bstart < 0) + new_bstart = bindex; + if (new_bend < 0) + new_bend = bindex; + set_dbstart(dentry, new_bstart); + set_dbend(dentry, new_bend); + +} + +/* set lower inode ptr and update bstart & bend if necessary */ +static void __set_inode(struct dentry * upper, struct dentry * lower, + int bindex) +{ + unionfs_set_lower_inode_idx(upper->d_inode, bindex, + igrab(lower->d_inode)); + if (likely(ibstart(upper->d_inode) > bindex)) + ibstart(upper->d_inode) = bindex; + if (likely(ibend(upper->d_inode) < bindex)) + ibend(upper->d_inode) = bindex; + +} + +/* set lower dentry ptr and update bstart & bend if necessary */ +static void __set_dentry(struct dentry * upper, struct dentry * lower, + int bindex) +{ + unionfs_set_lower_dentry_idx(upper, bindex, lower); + if (likely(dbstart(upper) > bindex)) + set_dbstart(upper, bindex); + if (likely(dbend(upper) < bindex)) + set_dbend(upper, bindex); +} + +/* This function replicates the directory structure upto given dentry + * in the bindex branch. + */ +static struct dentry *create_parents_named(struct inode *dir, + struct dentry *dentry, + const char *name, int bindex) +{ + int err; + struct dentry *child_dentry; + struct dentry *parent_dentry; + struct dentry *hidden_parent_dentry = NULL; + struct dentry *hidden_dentry = NULL; + const char *childname; + unsigned int childnamelen; + + int old_kmalloc_size; + int kmalloc_size; + int num_dentry; + int count; + + int old_bstart; + int old_bend; + struct dentry **path = NULL; + struct dentry **tmp_path; + struct super_block *sb; + + verify_locked(dentry); + + /* There is no sense allocating any less than the minimum. */ + kmalloc_size = malloc_sizes[0].cs_size; + num_dentry = kmalloc_size / sizeof(struct dentry *); + + if ((err = is_robranch_super(dir->i_sb, bindex))) { + hidden_dentry = ERR_PTR(err); + goto out; + } + + old_bstart = dbstart(dentry); + old_bend = dbend(dentry); + + hidden_dentry = ERR_PTR(-ENOMEM); + path = kzalloc(kmalloc_size, GFP_KERNEL); + if (!path) + goto out; + + /* assume the negative dentry of unionfs as the parent dentry */ + parent_dentry = dentry; + + count = 0; + /* This loop finds the first parent that exists in the given branch. + * We start building the directory structure from there. At the end + * of the loop, the following should hold: + * - child_dentry is the first nonexistent child + * - parent_dentry is the first existent parent + * - path[0] is the = deepest child + * - path[count] is the first child to create + */ + do { + child_dentry = parent_dentry; + + /* find the parent directory dentry in unionfs */ + parent_dentry = child_dentry->d_parent; + unionfs_lock_dentry(parent_dentry); + + /* find out the hidden_parent_dentry in the given branch */ + hidden_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex); + + /* store the child dentry */ + path[count++] = child_dentry; + + /* grow path table */ + if (count == num_dentry) { + old_kmalloc_size = kmalloc_size; + kmalloc_size *= 2; + num_dentry = kmalloc_size / sizeof(struct dentry *); + + tmp_path = kzalloc(kmalloc_size, GFP_KERNEL); + if (!tmp_path) { + hidden_dentry = ERR_PTR(-ENOMEM); + goto out; + } + memcpy(tmp_path, path, old_kmalloc_size); + kfree(path); + path = tmp_path; + tmp_path = NULL; + } + + } while (!hidden_parent_dentry); + count--; + + sb = dentry->d_sb; + + /* This is basically while(child_dentry != dentry). This loop is + * horrible to follow and should be replaced with cleaner code. + */ + while (1) { + /* get hidden parent dir in the current branch */ + hidden_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex); + unionfs_unlock_dentry(parent_dentry); + + /* init the values to lookup */ + childname = child_dentry->d_name.name; + childnamelen = child_dentry->d_name.len; + + if (child_dentry != dentry) { + /* lookup child in the underlying file system */ + hidden_dentry = + lookup_one_len(childname, hidden_parent_dentry, + childnamelen); + if (IS_ERR(hidden_dentry)) + goto out; + } else { + + /* is the name a whiteout of the childname ? + * lookup the whiteout child in the underlying file system + */ + hidden_dentry = + lookup_one_len(name, hidden_parent_dentry, + strlen(name)); + if (IS_ERR(hidden_dentry)) + goto out; + + /* Replace the current dentry (if any) with the new one. */ + dput(unionfs_lower_dentry_idx(dentry, bindex)); + unionfs_set_lower_dentry_idx(dentry, bindex, hidden_dentry); + + __cleanup_dentry(dentry, bindex, old_bstart, old_bend); + break; + } + + if (hidden_dentry->d_inode) { + /* since this already exists we dput to avoid + * multiple references on the same dentry + */ + dput(hidden_dentry); + } else { + struct sioq_args args; + + /* its a negative dentry, create a new dir */ + hidden_parent_dentry = lock_parent(hidden_dentry); + + args.mkdir.parent = hidden_parent_dentry->d_inode; + args.mkdir.dentry = hidden_dentry; + args.mkdir.mode = child_dentry->d_inode->i_mode; + + run_sioq(__unionfs_mkdir, &args); + err = args.err; + + if (!err) + err = copyup_permissions(dir->i_sb, + child_dentry, hidden_dentry); + unlock_dir(hidden_parent_dentry); + if (err) { + dput(hidden_dentry); + hidden_dentry = ERR_PTR(err); + goto out; + } + + } + + __set_inode(child_dentry, hidden_dentry, bindex); + __set_dentry(child_dentry, hidden_dentry, bindex); + + parent_dentry = child_dentry; + child_dentry = path[--count]; + } +out: + kfree(path); + return hidden_dentry; +} + diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c new file mode 100644 index 0000000..3721409 --- /dev/null +++ b/fs/unionfs/dentry.c @@ -0,0 +1,238 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* + * returns 1 if valid, 0 otherwise. + */ +int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + int valid = 1; /* default is valid (1); invalid is 0. */ + struct dentry *hidden_dentry; + int bindex, bstart, bend; + int sbgen, dgen; + int positive = 0; + int locked = 0; + int restart = 0; + int interpose_flag; + + struct nameidata lowernd; /* TODO: be gentler to the stack */ + + if (nd) + memcpy(&lowernd, nd, sizeof(struct nameidata)); + else + memset(&lowernd, 0, sizeof(struct nameidata)); + +restart: + verify_locked(dentry); + + /* if the dentry is unhashed, do NOT revalidate */ + if (d_deleted(dentry)) { + printk(KERN_DEBUG "unhashed dentry being revalidated: %*s\n", + dentry->d_name.len, dentry->d_name.name); + goto out; + } + + BUG_ON(dbstart(dentry) == -1); + if (dentry->d_inode) + positive = 1; + dgen = atomic_read(&UNIONFS_D(dentry)->generation); + sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation); + /* If we are working on an unconnected dentry, then there is no + * revalidation to be done, because this file does not exist within the + * namespace, and Unionfs operates on the namespace, not data. + */ + if (sbgen != dgen) { + struct dentry *result; + int pdgen; + + unionfs_read_lock(dentry->d_sb); + locked = 1; + + /* The root entry should always be valid */ + BUG_ON(IS_ROOT(dentry)); + + /* We can't work correctly if our parent isn't valid. */ + pdgen = atomic_read(&UNIONFS_D(dentry->d_parent)->generation); + if (!restart && (pdgen != sbgen)) { + unionfs_read_unlock(dentry->d_sb); + locked = 0; + /* We must be locked before our parent. */ + if (! + (dentry->d_parent->d_op-> + d_revalidate(dentry->d_parent, nd))) { + valid = 0; + goto out; + } + restart = 1; + goto restart; + } + BUG_ON(pdgen != sbgen); + + /* Free the pointers for our inodes and this dentry. */ + bstart = dbstart(dentry); + bend = dbend(dentry); + if (bstart >= 0) { + struct dentry *hidden_dentry; + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = + unionfs_lower_dentry_idx(dentry, bindex); + dput(hidden_dentry); + } + } + set_dbstart(dentry, -1); + set_dbend(dentry, -1); + + interpose_flag = INTERPOSE_REVAL_NEG; + if (positive) { + interpose_flag = INTERPOSE_REVAL; + mutex_lock(&dentry->d_inode->i_mutex); + bstart = ibstart(dentry->d_inode); + bend = ibend(dentry->d_inode); + if (bstart >= 0) { + struct inode *hidden_inode; + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_inode = + unionfs_lower_inode_idx(dentry->d_inode, + bindex); + iput(hidden_inode); + } + } + kfree(UNIONFS_I(dentry->d_inode)->lower_inodes); + UNIONFS_I(dentry->d_inode)->lower_inodes = NULL; + ibstart(dentry->d_inode) = -1; + ibend(dentry->d_inode) = -1; + mutex_unlock(&dentry->d_inode->i_mutex); + } + + result = unionfs_lookup_backend(dentry, &lowernd, interpose_flag); + if (result) { + if (IS_ERR(result)) { + valid = 0; + goto out; + } + /* current unionfs_lookup_backend() doesn't return + * a valid dentry + */ + dput(dentry); + dentry = result; + } + + if (positive && UNIONFS_I(dentry->d_inode)->stale) { + make_bad_inode(dentry->d_inode); + d_drop(dentry); + valid = 0; + goto out; + } + goto out; + } + + /* The revalidation must occur across all branches */ + bstart = dbstart(dentry); + bend = dbend(dentry); + BUG_ON(bstart == -1); + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry || !hidden_dentry->d_op + || !hidden_dentry->d_op->d_revalidate) + continue; + + if (!hidden_dentry->d_op->d_revalidate(hidden_dentry, nd)) + valid = 0; + } + + if (!dentry->d_inode) + valid = 0; + + if (valid) { + fsstack_copy_attr_all(dentry->d_inode, + unionfs_lower_inode(dentry->d_inode), + unionfs_get_nlinks); + fsstack_copy_inode_size(dentry->d_inode, + unionfs_lower_inode(dentry->d_inode)); + } + +out: + if (locked) + unionfs_read_unlock(dentry->d_sb); + return valid; +} + +static int unionfs_d_revalidate_wrap(struct dentry *dentry, + struct nameidata *nd) +{ + int err; + + unionfs_lock_dentry(dentry); + err = unionfs_d_revalidate(dentry, nd); + unionfs_unlock_dentry(dentry); + + return err; +} + +static void unionfs_d_release(struct dentry *dentry) +{ + int bindex, bstart, bend; + + /* There is no reason to lock the dentry, because we have the only + * reference, but the printing functions verify that we have a lock + * on the dentry before calling dbstart, etc. + */ + unionfs_lock_dentry(dentry); + + /* this could be a negative dentry, so check first */ + if (!UNIONFS_D(dentry)) { + printk(KERN_DEBUG "dentry without private data: %.*s", + dentry->d_name.len, dentry->d_name.name); + goto out; + } else if (dbstart(dentry) < 0) { + /* this is due to a failed lookup */ + printk(KERN_DEBUG "dentry without hidden dentries : %.*s", + dentry->d_name.len, dentry->d_name.name); + goto out_free; + } + + /* Release all the hidden dentries */ + bstart = dbstart(dentry); + bend = dbend(dentry); + for (bindex = bstart; bindex <= bend; bindex++) { + dput(unionfs_lower_dentry_idx(dentry, bindex)); + mntput(unionfs_lower_mnt_idx(dentry, bindex)); + + unionfs_set_lower_dentry_idx(dentry, bindex, NULL); + unionfs_set_lower_mnt_idx(dentry, bindex, NULL); + } + /* free private data (unionfs_dentry_info) here */ + kfree(UNIONFS_D(dentry)->lower_paths); + UNIONFS_D(dentry)->lower_paths = NULL; + +out_free: + /* No need to unlock it, because it is disappeared. */ + free_dentry_private_data(UNIONFS_D(dentry)); + dentry->d_fsdata = NULL; /* just to be safe */ + +out: + return; +} + +struct dentry_operations unionfs_dops = { + .d_revalidate = unionfs_d_revalidate_wrap, + .d_release = unionfs_d_release, +}; + diff --git a/fs/unionfs/dirfops.c b/fs/unionfs/dirfops.c new file mode 100644 index 0000000..2b77fa9 --- /dev/null +++ b/fs/unionfs/dirfops.c @@ -0,0 +1,263 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* Make sure our rdstate is playing by the rules. */ +static void verify_rdstate_offset(struct unionfs_dir_state *rdstate) +{ + BUG_ON(rdstate->offset >= DIREOF); + BUG_ON(rdstate->cookie >= MAXRDCOOKIE); +} + +struct unionfs_getdents_callback { + struct unionfs_dir_state *rdstate; + void *dirent; + int entries_written; + int filldir_called; + int filldir_error; + filldir_t filldir; + struct super_block *sb; +}; + +/* based on generic filldir in fs/readir.c */ +static int unionfs_filldir(void *dirent, const char *name, int namelen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct unionfs_getdents_callback *buf = dirent; + struct filldir_node *found = NULL; + int err = 0; + int is_wh_entry = 0; + + buf->filldir_called++; + + if ((namelen > UNIONFS_WHLEN) && + !strncmp(name, UNIONFS_WHPFX, UNIONFS_WHLEN)) { + name += UNIONFS_WHLEN; + namelen -= UNIONFS_WHLEN; + is_wh_entry = 1; + } + + found = find_filldir_node(buf->rdstate, name, namelen); + + if (found) + goto out; + + /* if 'name' isn't a whiteout, filldir it. */ + if (!is_wh_entry) { + off_t pos = rdstate2offset(buf->rdstate); + u64 unionfs_ino = ino; + + if (!err) { + err = buf->filldir(buf->dirent, name, namelen, pos, + unionfs_ino, d_type); + buf->rdstate->offset++; + verify_rdstate_offset(buf->rdstate); + } + } + /* If we did fill it, stuff it in our hash, otherwise return an error */ + if (err) { + buf->filldir_error = err; + goto out; + } + buf->entries_written++; + if ((err = add_filldir_node(buf->rdstate, name, namelen, + buf->rdstate->bindex, is_wh_entry))) + buf->filldir_error = err; + +out: + return err; +} + +static int unionfs_readdir(struct file *file, void *dirent, filldir_t filldir) +{ + int err = 0; + struct file *hidden_file = NULL; + struct inode *inode = NULL; + struct unionfs_getdents_callback buf; + struct unionfs_dir_state *uds; + int bend; + loff_t offset; + + if ((err = unionfs_file_revalidate(file, 0))) + goto out; + + inode = file->f_dentry->d_inode; + + uds = UNIONFS_F(file)->rdstate; + if (!uds) { + if (file->f_pos == DIREOF) { + goto out; + } else if (file->f_pos > 0) { + uds = find_rdstate(inode, file->f_pos); + if (!uds) { + err = -ESTALE; + goto out; + } + UNIONFS_F(file)->rdstate = uds; + } else { + init_rdstate(file); + uds = UNIONFS_F(file)->rdstate; + } + } + bend = fbend(file); + + while (uds->bindex <= bend) { + hidden_file = unionfs_lower_file_idx(file, uds->bindex); + if (!hidden_file) { + uds->bindex++; + uds->dirpos = 0; + continue; + } + + /* prepare callback buffer */ + buf.filldir_called = 0; + buf.filldir_error = 0; + buf.entries_written = 0; + buf.dirent = dirent; + buf.filldir = filldir; + buf.rdstate = uds; + buf.sb = inode->i_sb; + + /* Read starting from where we last left off. */ + offset = vfs_llseek(hidden_file, uds->dirpos, 0); + if (offset < 0) { + err = offset; + goto out; + } + err = vfs_readdir(hidden_file, unionfs_filldir, &buf); + /* Save the position for when we continue. */ + + offset = vfs_llseek(hidden_file, 0, 1); + if (offset < 0) { + err = offset; + goto out; + } + uds->dirpos = offset; + + /* Copy the atime. */ + fsstack_copy_attr_atime(inode, hidden_file->f_dentry->d_inode); + + if (err < 0) + goto out; + + if (buf.filldir_error) + break; + + if (!buf.entries_written) { + uds->bindex++; + uds->dirpos = 0; + } + } + + if (!buf.filldir_error && uds->bindex >= bend) { + /* Save the number of hash entries for next time. */ + UNIONFS_I(inode)->hashsize = uds->hashentries; + free_rdstate(uds); + UNIONFS_F(file)->rdstate = NULL; + file->f_pos = DIREOF; + } else + file->f_pos = rdstate2offset(uds); + +out: + return err; +} + +/* This is not meant to be a generic repositioning function. If you do + * things that aren't supported, then we return EINVAL. + * + * What is allowed: + * (1) seeking to the same position that you are currently at + * This really has no effect, but returns where you are. + * (2) seeking to the beginning of the file + * This throws out all state, and lets you begin again. + */ +static loff_t unionfs_dir_llseek(struct file *file, loff_t offset, int origin) +{ + struct unionfs_dir_state *rdstate; + loff_t err; + + if ((err = unionfs_file_revalidate(file, 0))) + goto out; + + rdstate = UNIONFS_F(file)->rdstate; + + /* We let users seek to their current position, but not anywhere else. */ + if (!offset) { + switch (origin) { + case SEEK_SET: + if (rdstate) { + free_rdstate(rdstate); + UNIONFS_F(file)->rdstate = NULL; + } + init_rdstate(file); + err = 0; + break; + case SEEK_CUR: + err = file->f_pos; + break; + case SEEK_END: + /* Unsupported, because we would break everything. */ + err = -EINVAL; + break; + } + } else { + switch (origin) { + case SEEK_SET: + if (rdstate) { + if (offset == rdstate2offset(rdstate)) + err = offset; + else if (file->f_pos == DIREOF) + err = DIREOF; + else + err = -EINVAL; + } else { + rdstate = find_rdstate(file->f_dentry->d_inode, + offset); + if (rdstate) { + UNIONFS_F(file)->rdstate = rdstate; + err = rdstate->offset; + } else + err = -EINVAL; + } + break; + case SEEK_CUR: + case SEEK_END: + /* Unsupported, because we would break everything. */ + err = -EINVAL; + break; + } + } + +out: + return err; +} + +/* Trimmed directory options, we shouldn't pass everything down since + * we don't want to operate on partial directories. + */ +struct file_operations unionfs_dir_fops = { + .llseek = unionfs_dir_llseek, + .read = generic_read_dir, + .readdir = unionfs_readdir, + .unlocked_ioctl = unionfs_ioctl, + .open = unionfs_open, + .release = unionfs_file_release, + .flush = unionfs_flush, +}; + diff --git a/fs/unionfs/dirhelper.c b/fs/unionfs/dirhelper.c new file mode 100644 index 0000000..0da8a8e --- /dev/null +++ b/fs/unionfs/dirhelper.c @@ -0,0 +1,270 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* Delete all of the whiteouts in a given directory for rmdir. + * + * hidden directory inode should be locked + */ +int do_delete_whiteouts(struct dentry *dentry, int bindex, + struct unionfs_dir_state *namelist) +{ + int err = 0; + struct dentry *hidden_dir_dentry = NULL; + struct dentry *hidden_dentry; + char *name = NULL, *p; + struct inode *hidden_dir; + + int i; + struct list_head *pos; + struct filldir_node *cursor; + + /* Find out hidden parent dentry */ + hidden_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex); + BUG_ON(!S_ISDIR(hidden_dir_dentry->d_inode->i_mode)); + hidden_dir = hidden_dir_dentry->d_inode; + BUG_ON(!S_ISDIR(hidden_dir->i_mode)); + + err = -ENOMEM; + name = __getname(); + if (!name) + goto out; + strcpy(name, UNIONFS_WHPFX); + p = name + UNIONFS_WHLEN; + + err = 0; + for (i = 0; !err && i < namelist->size; i++) { + list_for_each(pos, &namelist->list[i]) { + cursor = + list_entry(pos, struct filldir_node, file_list); + /* Only operate on whiteouts in this branch. */ + if (cursor->bindex != bindex) + continue; + if (!cursor->whiteout) + continue; + + strcpy(p, cursor->name); + hidden_dentry = + lookup_one_len(name, hidden_dir_dentry, + cursor->namelen + UNIONFS_WHLEN); + if (IS_ERR(hidden_dentry)) { + err = PTR_ERR(hidden_dentry); + break; + } + if (hidden_dentry->d_inode) + err = vfs_unlink(hidden_dir, hidden_dentry); + dput(hidden_dentry); + if (err) + break; + } + } + + __putname(name); + + /* After all of the removals, we should copy the attributes once. */ + fsstack_copy_attr_times(dentry->d_inode, hidden_dir_dentry->d_inode); + +out: + return err; +} + +/* delete whiteouts in a dir (for rmdir operation) using sioq if necessary */ +int delete_whiteouts(struct dentry *dentry, int bindex, + struct unionfs_dir_state *namelist) +{ + int err; + struct super_block *sb; + struct dentry *hidden_dir_dentry; + struct inode *hidden_dir; + + struct sioq_args args; + + sb = dentry->d_sb; + unionfs_read_lock(sb); + + BUG_ON(!S_ISDIR(dentry->d_inode->i_mode)); + BUG_ON(bindex < dbstart(dentry)); + BUG_ON(bindex > dbend(dentry)); + err = is_robranch_super(sb, bindex); + if (err) + goto out; + + hidden_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex); + BUG_ON(!S_ISDIR(hidden_dir_dentry->d_inode->i_mode)); + hidden_dir = hidden_dir_dentry->d_inode; + BUG_ON(!S_ISDIR(hidden_dir->i_mode)); + + mutex_lock(&hidden_dir->i_mutex); + if (!permission(hidden_dir, MAY_WRITE | MAY_EXEC, NULL)) + err = do_delete_whiteouts(dentry, bindex, namelist); + else { + args.deletewh.namelist = namelist; + args.deletewh.dentry = dentry; + args.deletewh.bindex = bindex; + run_sioq(__delete_whiteouts, &args); + err = args.err; + } + mutex_unlock(&hidden_dir->i_mutex); + +out: + unionfs_read_unlock(sb); + return err; +} + +#define RD_NONE 0 +#define RD_CHECK_EMPTY 1 +/* The callback structure for check_empty. */ +struct unionfs_rdutil_callback { + int err; + int filldir_called; + struct unionfs_dir_state *rdstate; + int mode; +}; + +/* This filldir function makes sure only whiteouts exist within a directory. */ +static int readdir_util_callback(void *dirent, const char *name, int namelen, + loff_t offset, u64 ino, unsigned int d_type) +{ + int err = 0; + struct unionfs_rdutil_callback *buf = dirent; + int whiteout = 0; + struct filldir_node *found; + + buf->filldir_called = 1; + + if (name[0] == '.' && (namelen == 1 || (name[1] == '.' && namelen == 2))) + goto out; + + if (namelen > UNIONFS_WHLEN && + !strncmp(name, UNIONFS_WHPFX, UNIONFS_WHLEN)) { + namelen -= UNIONFS_WHLEN; + name += UNIONFS_WHLEN; + whiteout = 1; + } + + found = find_filldir_node(buf->rdstate, name, namelen); + /* If it was found in the table there was a previous whiteout. */ + if (found) + goto out; + + /* If it wasn't found and isn't a whiteout, the directory isn't empty. */ + err = -ENOTEMPTY; + if ((buf->mode == RD_CHECK_EMPTY) && !whiteout) + goto out; + + err = add_filldir_node(buf->rdstate, name, namelen, + buf->rdstate->bindex, whiteout); + +out: + buf->err = err; + return err; +} + +/* Is a directory logically empty? */ +int check_empty(struct dentry *dentry, struct unionfs_dir_state **namelist) +{ + int err = 0; + struct dentry *hidden_dentry = NULL; + struct super_block *sb; + struct file *hidden_file; + struct unionfs_rdutil_callback *buf = NULL; + int bindex, bstart, bend, bopaque; + + sb = dentry->d_sb; + + unionfs_read_lock(sb); + + BUG_ON(!S_ISDIR(dentry->d_inode->i_mode)); + + if ((err = unionfs_partial_lookup(dentry))) + goto out; + + bstart = dbstart(dentry); + bend = dbend(dentry); + bopaque = dbopaque(dentry); + if (0 <= bopaque && bopaque < bend) + bend = bopaque; + + buf = kmalloc(sizeof(struct unionfs_rdutil_callback), GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto out; + } + buf->err = 0; + buf->mode = RD_CHECK_EMPTY; + buf->rdstate = alloc_rdstate(dentry->d_inode, bstart); + if (!buf->rdstate) { + err = -ENOMEM; + goto out; + } + + /* Process the hidden directories with rdutil_callback as a filldir. */ + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) + continue; + if (!hidden_dentry->d_inode) + continue; + if (!S_ISDIR(hidden_dentry->d_inode->i_mode)) + continue; + + dget(hidden_dentry); + mntget(unionfs_lower_mnt_idx(dentry, bindex)); + branchget(sb, bindex); + hidden_file = + dentry_open(hidden_dentry, unionfs_lower_mnt_idx(dentry, bindex), + O_RDONLY); + if (IS_ERR(hidden_file)) { + err = PTR_ERR(hidden_file); + dput(hidden_dentry); + branchput(sb, bindex); + goto out; + } + + do { + buf->filldir_called = 0; + buf->rdstate->bindex = bindex; + err = vfs_readdir(hidden_file, + readdir_util_callback, buf); + if (buf->err) + err = buf->err; + } while ((err >= 0) && buf->filldir_called); + + /* fput calls dput for hidden_dentry */ + fput(hidden_file); + branchput(sb, bindex); + + if (err < 0) + goto out; + } + +out: + if (buf) { + if (namelist && !err) + *namelist = buf->rdstate; + else if (buf->rdstate) + free_rdstate(buf->rdstate); + kfree(buf); + } + + unionfs_read_unlock(sb); + + return err; +} + diff --git a/fs/unionfs/fanout.h b/fs/unionfs/fanout.h new file mode 100644 index 0000000..e2acb75 --- /dev/null +++ b/fs/unionfs/fanout.h @@ -0,0 +1,210 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _FANOUT_H_ +#define _FANOUT_H_ + +/* Inode to private data */ +static inline struct unionfs_inode_info *UNIONFS_I(const struct inode *inode) +{ + return container_of(inode, struct unionfs_inode_info, vfs_inode); +} + +#define ibstart(ino) (UNIONFS_I(ino)->bstart) +#define ibend(ino) (UNIONFS_I(ino)->bend) + +/* Superblock to private data */ +#define UNIONFS_SB(super) ((struct unionfs_sb_info *)(super)->s_fs_info) +#define sbstart(sb) 0 +#define sbend(sb) (UNIONFS_SB(sb)->bend) +#define sbmax(sb) (UNIONFS_SB(sb)->bend + 1) + +/* File to private Data */ +#define UNIONFS_F(file) ((struct unionfs_file_info *)((file)->private_data)) +#define fbstart(file) (UNIONFS_F(file)->bstart) +#define fbend(file) (UNIONFS_F(file)->bend) + +/* File to lower file. */ +static inline struct file *unionfs_lower_file(const struct file *f) +{ + return UNIONFS_F(f)->lower_files[fbstart(f)]; +} + +static inline struct file *unionfs_lower_file_idx(const struct file *f, int index) +{ + return UNIONFS_F(f)->lower_files[index]; +} + +static inline void unionfs_set_lower_file_idx(struct file *f, int index, struct file *val) +{ + UNIONFS_F(f)->lower_files[index] = val; +} + +static inline void unionfs_set_lower_file(struct file *f, struct file *val) +{ + UNIONFS_F(f)->lower_files[fbstart(f)] = val; +} + +/* Inode to lower inode. */ +static inline struct inode *unionfs_lower_inode(const struct inode *i) +{ + return UNIONFS_I(i)->lower_inodes[ibstart(i)]; +} + +static inline struct inode *unionfs_lower_inode_idx(const struct inode *i, int index) +{ + return UNIONFS_I(i)->lower_inodes[index]; +} + +static inline void unionfs_set_lower_inode_idx(struct inode *i, int index, + struct inode *val) +{ + UNIONFS_I(i)->lower_inodes[index] = val; +} + +static inline void unionfs_set_lower_inode(struct inode *i, struct inode *val) +{ + UNIONFS_I(i)->lower_inodes[ibstart(i)] = val; +} + +/* Superblock to lower superblock. */ +static inline struct super_block *unionfs_lower_super(const struct super_block *sb) +{ + return UNIONFS_SB(sb)->data[sbstart(sb)].sb; +} + +static inline struct super_block *unionfs_lower_super_idx(const struct super_block *sb, int index) +{ + return UNIONFS_SB(sb)->data[index].sb; +} + +static inline void unionfs_set_lower_super_idx(struct super_block *sb, int index, + struct super_block *val) +{ + UNIONFS_SB(sb)->data[index].sb = val; +} + +static inline void unionfs_set_lower_super(struct super_block *sb, struct super_block *val) +{ + UNIONFS_SB(sb)->data[sbstart(sb)].sb = val; +} + +/* Branch count macros. */ +static inline int branch_count(const struct super_block *sb, int index) +{ + return atomic_read(&UNIONFS_SB(sb)->data[index].sbcount); +} + +static inline void set_branch_count(struct super_block *sb, int index, int val) +{ + atomic_set(&UNIONFS_SB(sb)->data[index].sbcount, val); +} + +static inline void branchget(struct super_block *sb, int index) +{ + atomic_inc(&UNIONFS_SB(sb)->data[index].sbcount); +} + +static inline void branchput(struct super_block *sb, int index) +{ + atomic_dec(&UNIONFS_SB(sb)->data[index].sbcount); +} + +/* Dentry macros */ +static inline struct unionfs_dentry_info *UNIONFS_D(const struct dentry *dent) +{ + return dent->d_fsdata; +} + +static inline int dbstart(const struct dentry *dent) +{ + return UNIONFS_D(dent)->bstart; +} + +static inline void set_dbstart(struct dentry *dent, int val) +{ + UNIONFS_D(dent)->bstart = val; +} + +static inline int dbend(const struct dentry *dent) +{ + return UNIONFS_D(dent)->bend; +} + +static inline void set_dbend(struct dentry *dent, int val) +{ + UNIONFS_D(dent)->bend = val; +} + +static inline int dbopaque(const struct dentry *dent) +{ + return UNIONFS_D(dent)->bopaque; +} + +static inline void set_dbopaque(struct dentry *dent, int val) +{ + UNIONFS_D(dent)->bopaque = val; +} + +static inline void unionfs_set_lower_dentry_idx(struct dentry *dent, int index, + struct dentry *val) +{ + UNIONFS_D(dent)->lower_paths[index].dentry = val; +} + +static inline struct dentry *unionfs_lower_dentry_idx(const struct dentry *dent, int index) +{ + return UNIONFS_D(dent)->lower_paths[index].dentry; +} + +static inline struct dentry *unionfs_lower_dentry(const struct dentry *dent) +{ + return unionfs_lower_dentry_idx(dent, dbstart(dent)); +} + +static inline void unionfs_set_lower_mnt_idx(struct dentry *dent, int index, + struct vfsmount *mnt) +{ + UNIONFS_D(dent)->lower_paths[index].mnt = mnt; +} + +static inline struct vfsmount *unionfs_lower_mnt_idx(const struct dentry *dent, int index) +{ + return UNIONFS_D(dent)->lower_paths[index].mnt; +} + +static inline struct vfsmount *unionfs_lower_mnt(const struct dentry *dent) +{ + return unionfs_lower_mnt_idx(dent,dbstart(dent)); +} + +/* Macros for locking a dentry. */ +static inline void unionfs_lock_dentry(struct dentry *d) +{ + mutex_lock(&UNIONFS_D(d)->lock); +} + +static inline void unionfs_unlock_dentry(struct dentry *d) +{ + mutex_unlock(&UNIONFS_D(d)->lock); +} + +static inline void verify_locked(struct dentry *d) +{ +} + +#endif /* _FANOUT_H */ diff --git a/fs/unionfs/file.c b/fs/unionfs/file.c new file mode 100644 index 0000000..9ce092d --- /dev/null +++ b/fs/unionfs/file.c @@ -0,0 +1,252 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/******************* + * File Operations * + *******************/ + +static loff_t unionfs_llseek(struct file *file, loff_t offset, int origin) +{ + loff_t err; + struct file *hidden_file = NULL; + + if ((err = unionfs_file_revalidate(file, 0))) + goto out; + + hidden_file = unionfs_lower_file(file); + /* always set hidden position to this one */ + hidden_file->f_pos = file->f_pos; + + memcpy(&hidden_file->f_ra, &file->f_ra, sizeof(struct file_ra_state)); + + if (hidden_file->f_op && hidden_file->f_op->llseek) + err = hidden_file->f_op->llseek(hidden_file, offset, origin); + else + err = generic_file_llseek(hidden_file, offset, origin); + + if (err < 0) + goto out; + if (err != file->f_pos) { + file->f_pos = err; + file->f_version++; + } +out: + return err; +} + +static ssize_t unionfs_read(struct file * file, char __user * buf, + size_t count, loff_t * ppos) +{ + struct file *hidden_file; + loff_t pos = *ppos; + int err; + + if ((err = unionfs_file_revalidate(file, 0))) + goto out; + + err = -EINVAL; + hidden_file = unionfs_lower_file(file); + if (!hidden_file->f_op || !hidden_file->f_op->read) + goto out; + + err = hidden_file->f_op->read(hidden_file, buf, count, &pos); + *ppos = pos; + +out: + return err; +} + +static ssize_t __unionfs_write(struct file * file, const char __user * buf, + size_t count, loff_t * ppos) +{ + int err = -EINVAL; + struct file *hidden_file = NULL; + struct inode *inode; + struct inode *hidden_inode; + loff_t pos = *ppos; + int bstart, bend; + + inode = file->f_dentry->d_inode; + + bstart = fbstart(file); + bend = fbend(file); + + BUG_ON(bstart == -1); + + hidden_file = unionfs_lower_file(file); + hidden_inode = hidden_file->f_dentry->d_inode; + + if (!hidden_file->f_op || !hidden_file->f_op->write) + goto out; + + /* adjust for append -- seek to the end of the file */ + if (file->f_flags & O_APPEND) + pos = inode->i_size; + + err = hidden_file->f_op->write(hidden_file, buf, count, &pos); + + /* + * copy ctime and mtime from lower layer attributes + * atime is unchanged for both layers + */ + if (err >= 0) + fsstack_copy_attr_times(inode, hidden_inode); + + *ppos = pos; + + /* update this inode's size */ + if (pos > inode->i_size) + inode->i_size = pos; +out: + return err; +} + +static ssize_t unionfs_write(struct file * file, const char __user * buf, + size_t count, loff_t * ppos) +{ + int err = 0; + + if ((err = unionfs_file_revalidate(file, 1))) + goto out; + + err = __unionfs_write(file, buf, count, ppos); + +out: + return err; +} + +static int unionfs_file_readdir(struct file *file, void *dirent, + filldir_t filldir) +{ + return -ENOTDIR; +} + +static unsigned int unionfs_poll(struct file *file, poll_table * wait) +{ + unsigned int mask = DEFAULT_POLLMASK; + struct file *hidden_file = NULL; + + if (unionfs_file_revalidate(file, 0)) { + /* We should pretend an error happend. */ + mask = POLLERR | POLLIN | POLLOUT; + goto out; + } + + hidden_file = unionfs_lower_file(file); + + if (!hidden_file->f_op || !hidden_file->f_op->poll) + goto out; + + mask = hidden_file->f_op->poll(hidden_file, wait); + +out: + return mask; +} + +static int __do_mmap(struct file *file, struct vm_area_struct *vma) +{ + int err; + struct file *hidden_file; + + hidden_file = unionfs_lower_file(file); + + err = -ENODEV; + if (!hidden_file->f_op || !hidden_file->f_op->mmap) + goto out; + + vma->vm_file = hidden_file; + err = hidden_file->f_op->mmap(hidden_file, vma); + get_file(hidden_file); /* make sure it doesn't get freed on us */ + fput(file); /* no need to keep extra ref on ours */ +out: + return err; +} + +static int unionfs_mmap(struct file *file, struct vm_area_struct *vma) +{ + int err = 0; + int willwrite; + + /* This might could be deferred to mmap's writepage. */ + willwrite = ((vma->vm_flags | VM_SHARED | VM_WRITE) == vma->vm_flags); + if ((err = unionfs_file_revalidate(file, willwrite))) + goto out; + + err = __do_mmap(file, vma); + +out: + return err; +} + +static int unionfs_fsync(struct file *file, struct dentry *dentry, int datasync) +{ + int err; + struct file *hidden_file = NULL; + + if ((err = unionfs_file_revalidate(file, 1))) + goto out; + + hidden_file = unionfs_lower_file(file); + + err = -EINVAL; + if (!hidden_file->f_op || !hidden_file->f_op->fsync) + goto out; + + mutex_lock(&hidden_file->f_dentry->d_inode->i_mutex); + err = hidden_file->f_op->fsync(hidden_file, hidden_file->f_dentry, + datasync); + mutex_unlock(&hidden_file->f_dentry->d_inode->i_mutex); + +out: + return err; +} + +static int unionfs_fasync(int fd, struct file *file, int flag) +{ + int err = 0; + struct file *hidden_file = NULL; + + if ((err = unionfs_file_revalidate(file, 1))) + goto out; + + hidden_file = unionfs_lower_file(file); + + if (hidden_file->f_op && hidden_file->f_op->fasync) + err = hidden_file->f_op->fasync(fd, hidden_file, flag); + +out: + return err; +} + +struct file_operations unionfs_main_fops = { + .llseek = unionfs_llseek, + .read = unionfs_read, + .write = unionfs_write, + .readdir = unionfs_file_readdir, + .poll = unionfs_poll, + .unlocked_ioctl = unionfs_ioctl, + .mmap = unionfs_mmap, + .open = unionfs_open, + .flush = unionfs_flush, + .release = unionfs_file_release, + .fsync = unionfs_fsync, + .fasync = unionfs_fasync, +}; + diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c new file mode 100644 index 0000000..1b2e8a8 --- /dev/null +++ b/fs/unionfs/inode.c @@ -0,0 +1,956 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +static int unionfs_create(struct inode *parent, struct dentry *dentry, + int mode, struct nameidata *nd) +{ + int err = 0; + struct dentry *hidden_dentry = NULL; + struct dentry *wh_dentry = NULL; + struct dentry *new_hidden_dentry; + struct dentry *hidden_parent_dentry = NULL; + int bindex = 0, bstart; + char *name = NULL; + + unionfs_lock_dentry(dentry); + + /* We start out in the leftmost branch. */ + bstart = dbstart(dentry); + hidden_dentry = unionfs_lower_dentry(dentry); + + /* check if whiteout exists in this branch, i.e. lookup .wh.foo first */ + name = alloc_whname(dentry->d_name.name, dentry->d_name.len); + if (IS_ERR(name)) { + err = PTR_ERR(name); + goto out; + } + + wh_dentry = lookup_one_len(name, hidden_dentry->d_parent, + dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(wh_dentry)) { + err = PTR_ERR(wh_dentry); + wh_dentry = NULL; + goto out; + } + + if (wh_dentry->d_inode) { + /* .wh.foo has been found. */ + /* First truncate it and then rename it to foo (hence having + * the same overall effect as a normal create. + */ + struct dentry *hidden_dir_dentry; + struct iattr newattrs; + + mutex_lock(&wh_dentry->d_inode->i_mutex); + newattrs.ia_valid = ATTR_CTIME | ATTR_MODE | ATTR_ATIME + | ATTR_MTIME | ATTR_UID | ATTR_GID | ATTR_FORCE + | ATTR_KILL_SUID | ATTR_KILL_SGID; + + newattrs.ia_mode = mode & ~current->fs->umask; + newattrs.ia_uid = current->fsuid; + newattrs.ia_gid = current->fsgid; + + if (wh_dentry->d_inode->i_size != 0) { + newattrs.ia_valid |= ATTR_SIZE; + newattrs.ia_size = 0; + } + + err = notify_change(wh_dentry, &newattrs); + + mutex_unlock(&wh_dentry->d_inode->i_mutex); + + if (err) + printk(KERN_WARNING "unionfs: %s:%d: notify_change " + "failed: %d, ignoring..\n", + __FILE__, __LINE__, err); + + new_hidden_dentry = unionfs_lower_dentry(dentry); + dget(new_hidden_dentry); + + hidden_dir_dentry = dget_parent(wh_dentry); + lock_rename(hidden_dir_dentry, hidden_dir_dentry); + + if (!(err = is_robranch_super(dentry->d_sb, bstart))) { + err = vfs_rename(hidden_dir_dentry->d_inode, + wh_dentry, + hidden_dir_dentry->d_inode, + new_hidden_dentry); + } + if (!err) { + fsstack_copy_attr_times(parent, + new_hidden_dentry->d_parent->d_inode); + fsstack_copy_inode_size(parent, + new_hidden_dentry->d_parent->d_inode); + parent->i_nlink = unionfs_get_nlinks(parent); + } + + unlock_rename(hidden_dir_dentry, hidden_dir_dentry); + dput(hidden_dir_dentry); + + dput(new_hidden_dentry); + + if (err) { + /* exit if the error returned was NOT -EROFS */ + if (!IS_COPYUP_ERR(err)) + goto out; + /* We were not able to create the file in this + * branch, so, we try to create it in one branch to + * left + */ + bstart--; + } else { + /* reset the unionfs dentry to point to the .wh.foo + * entry. + */ + + /* Discard any old reference. */ + dput(unionfs_lower_dentry(dentry)); + + /* Trade one reference to another. */ + unionfs_set_lower_dentry_idx(dentry, bstart, wh_dentry); + wh_dentry = NULL; + + err = unionfs_interpose(dentry, parent->i_sb, 0); + goto out; + } + } + + for (bindex = bstart; bindex >= 0; bindex--) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) { + /* if hidden_dentry is NULL, create the entire + * dentry directory structure in branch 'bindex'. + * hidden_dentry will NOT be null when bindex == bstart + * because lookup passed as a negative unionfs dentry + * pointing to a lone negative underlying dentry */ + hidden_dentry = create_parents(parent, dentry, bindex); + if (!hidden_dentry || IS_ERR(hidden_dentry)) { + if (IS_ERR(hidden_dentry)) + err = PTR_ERR(hidden_dentry); + continue; + } + } + + hidden_parent_dentry = lock_parent(hidden_dentry); + if (IS_ERR(hidden_parent_dentry)) { + err = PTR_ERR(hidden_parent_dentry); + goto out; + } + /* We shouldn't create things in a read-only branch. */ + if (!(err = is_robranch_super(dentry->d_sb, bindex))) + err = vfs_create(hidden_parent_dentry->d_inode, + hidden_dentry, mode, nd); + + if (err || !hidden_dentry->d_inode) { + unlock_dir(hidden_parent_dentry); + + /* break out of for loop if the error wasn't -EROFS */ + if (!IS_COPYUP_ERR(err)) + break; + } else { + err = unionfs_interpose(dentry, parent->i_sb, 0); + if (!err) { + fsstack_copy_attr_times(parent, + hidden_parent_dentry->d_inode); + fsstack_copy_inode_size(parent, + hidden_parent_dentry->d_inode); + /* update number of links on parent directory */ + parent->i_nlink = unionfs_get_nlinks(parent); + } + unlock_dir(hidden_parent_dentry); + break; + } + } + +out: + dput(wh_dentry); + kfree(name); + + unionfs_unlock_dentry(dentry); + return err; +} + +static struct dentry *unionfs_lookup(struct inode *parent, + struct dentry *dentry, + struct nameidata *nd) +{ + struct path path_save; + struct dentry *ret; + + /* save the dentry & vfsmnt from namei */ + if (nd) { + path_save.dentry = nd->dentry; + path_save.mnt = nd->mnt; + } + + /* The locking is done by unionfs_lookup_backend. */ + ret = unionfs_lookup_backend(dentry, nd, INTERPOSE_LOOKUP); + + /* restore the dentry & vfsmnt in namei */ + if (nd) { + nd->dentry = path_save.dentry; + nd->mnt = path_save.mnt; + } + + return ret; +} + +static int unionfs_link(struct dentry *old_dentry, struct inode *dir, + struct dentry *new_dentry) +{ + int err = 0; + struct dentry *hidden_old_dentry = NULL; + struct dentry *hidden_new_dentry = NULL; + struct dentry *hidden_dir_dentry = NULL; + struct dentry *whiteout_dentry; + char *name = NULL; + + double_lock_dentry(new_dentry, old_dentry); + + hidden_new_dentry = unionfs_lower_dentry(new_dentry); + + /* check if whiteout exists in the branch of new dentry, i.e. lookup + * .wh.foo first. If present, delete it + */ + name = alloc_whname(new_dentry->d_name.name, new_dentry->d_name.len); + if (IS_ERR(name)) { + err = PTR_ERR(name); + goto out; + } + + whiteout_dentry = lookup_one_len(name, hidden_new_dentry->d_parent, + new_dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(whiteout_dentry)) { + err = PTR_ERR(whiteout_dentry); + goto out; + } + + if (!whiteout_dentry->d_inode) { + dput(whiteout_dentry); + whiteout_dentry = NULL; + } else { + /* found a .wh.foo entry, unlink it and then call vfs_link() */ + hidden_dir_dentry = lock_parent(whiteout_dentry); + err = is_robranch_super(new_dentry->d_sb, dbstart(new_dentry)); + if (!err) + err = vfs_unlink(hidden_dir_dentry->d_inode, + whiteout_dentry); + + fsstack_copy_attr_times(dir, hidden_dir_dentry->d_inode); + dir->i_nlink = unionfs_get_nlinks(dir); + unlock_dir(hidden_dir_dentry); + hidden_dir_dentry = NULL; + dput(whiteout_dentry); + if (err) + goto out; + } + + if (dbstart(old_dentry) != dbstart(new_dentry)) { + hidden_new_dentry = + create_parents(dir, new_dentry, dbstart(old_dentry)); + err = PTR_ERR(hidden_new_dentry); + if (IS_COPYUP_ERR(err)) + goto docopyup; + if (!hidden_new_dentry || IS_ERR(hidden_new_dentry)) + goto out; + } + hidden_new_dentry = unionfs_lower_dentry(new_dentry); + hidden_old_dentry = unionfs_lower_dentry(old_dentry); + + BUG_ON(dbstart(old_dentry) != dbstart(new_dentry)); + hidden_dir_dentry = lock_parent(hidden_new_dentry); + if (!(err = is_robranch(old_dentry))) + err = vfs_link(hidden_old_dentry, hidden_dir_dentry->d_inode, + hidden_new_dentry); + unlock_dir(hidden_dir_dentry); + +docopyup: + if (IS_COPYUP_ERR(err)) { + int old_bstart = dbstart(old_dentry); + int bindex; + + for (bindex = old_bstart - 1; bindex >= 0; bindex--) { + err = + copyup_dentry(old_dentry->d_parent-> + d_inode, old_dentry, + old_bstart, bindex, NULL, + old_dentry->d_inode->i_size); + if (!err) { + hidden_new_dentry = + create_parents(dir, new_dentry, bindex); + hidden_old_dentry = unionfs_lower_dentry(old_dentry); + hidden_dir_dentry = + lock_parent(hidden_new_dentry); + /* do vfs_link */ + err = vfs_link(hidden_old_dentry, + hidden_dir_dentry->d_inode, + hidden_new_dentry); + unlock_dir(hidden_dir_dentry); + goto check_link; + } + } + goto out; + } + +check_link: + if (err || !hidden_new_dentry->d_inode) + goto out; + + /* Its a hard link, so use the same inode */ + new_dentry->d_inode = igrab(old_dentry->d_inode); + d_instantiate(new_dentry, new_dentry->d_inode); + fsstack_copy_attr_all(dir, hidden_new_dentry->d_parent->d_inode, + unionfs_get_nlinks); + fsstack_copy_inode_size(dir, hidden_new_dentry->d_parent->d_inode); + + /* propagate number of hard-links */ + old_dentry->d_inode->i_nlink = unionfs_get_nlinks(old_dentry->d_inode); + +out: + if (!new_dentry->d_inode) + d_drop(new_dentry); + + kfree(name); + + unionfs_unlock_dentry(new_dentry); + unionfs_unlock_dentry(old_dentry); + + return err; +} + +static int unionfs_symlink(struct inode *dir, struct dentry *dentry, + const char *symname) +{ + int err = 0; + struct dentry *hidden_dentry = NULL; + struct dentry *whiteout_dentry = NULL; + struct dentry *hidden_dir_dentry = NULL; + umode_t mode; + int bindex = 0, bstart; + char *name = NULL; + + unionfs_lock_dentry(dentry); + + /* We start out in the leftmost branch. */ + bstart = dbstart(dentry); + + hidden_dentry = unionfs_lower_dentry(dentry); + + /* check if whiteout exists in this branch, i.e. lookup .wh.foo + * first. If present, delete it + */ + name = alloc_whname(dentry->d_name.name, dentry->d_name.len); + if (IS_ERR(name)) { + err = PTR_ERR(name); + goto out; + } + + whiteout_dentry = + lookup_one_len(name, hidden_dentry->d_parent, + dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(whiteout_dentry)) { + err = PTR_ERR(whiteout_dentry); + goto out; + } + + if (!whiteout_dentry->d_inode) { + dput(whiteout_dentry); + whiteout_dentry = NULL; + } else { + /* found a .wh.foo entry, unlink it and then call vfs_symlink() */ + hidden_dir_dentry = lock_parent(whiteout_dentry); + + if (!(err = is_robranch_super(dentry->d_sb, bstart))) + err = vfs_unlink(hidden_dir_dentry->d_inode, + whiteout_dentry); + dput(whiteout_dentry); + + fsstack_copy_attr_times(dir, hidden_dir_dentry->d_inode); + /* propagate number of hard-links */ + dir->i_nlink = unionfs_get_nlinks(dir); + + unlock_dir(hidden_dir_dentry); + + if (err) { + /* exit if the error returned was NOT -EROFS */ + if (!IS_COPYUP_ERR(err)) + goto out; + /* should now try to create symlink in the another branch */ + bstart--; + } + } + + /* deleted whiteout if it was present, now do a normal vfs_symlink() + * with possible recursive directory creation + */ + for (bindex = bstart; bindex >= 0; bindex--) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) { + /* if hidden_dentry is NULL, create the entire + * dentry directory structure in branch 'bindex'. + * hidden_dentry will NOT be null when bindex == + * bstart because lookup passed as a negative + * unionfs dentry pointing to a lone negative + * underlying dentry + */ + hidden_dentry = create_parents(dir, dentry, bindex); + if (!hidden_dentry || IS_ERR(hidden_dentry)) { + if (IS_ERR(hidden_dentry)) + err = PTR_ERR(hidden_dentry); + + printk(KERN_DEBUG "hidden dentry NULL (or error)" + "for bindex = %d\n", bindex); + continue; + } + } + + hidden_dir_dentry = lock_parent(hidden_dentry); + + if (!(err = is_robranch_super(dentry->d_sb, bindex))) { + mode = S_IALLUGO; + err = + vfs_symlink(hidden_dir_dentry->d_inode, + hidden_dentry, symname, mode); + } + unlock_dir(hidden_dir_dentry); + + if (err || !hidden_dentry->d_inode) { + /* break out of for loop if error returned was NOT -EROFS */ + if (!IS_COPYUP_ERR(err)) + break; + } else { + err = unionfs_interpose(dentry, dir->i_sb, 0); + if (!err) { + fsstack_copy_attr_times(dir, + hidden_dir_dentry->d_inode); + fsstack_copy_inode_size(dir, + hidden_dir_dentry->d_inode); + /* update number of links on parent directory */ + dir->i_nlink = unionfs_get_nlinks(dir); + } + break; + } + } + +out: + if (!dentry->d_inode) + d_drop(dentry); + + kfree(name); + unionfs_unlock_dentry(dentry); + return err; +} + +static int unionfs_mkdir(struct inode *parent, struct dentry *dentry, int mode) +{ + int err = 0; + struct dentry *hidden_dentry = NULL, *whiteout_dentry = NULL; + struct dentry *hidden_parent_dentry = NULL; + int bindex = 0, bstart; + char *name = NULL; + int whiteout_unlinked = 0; + struct sioq_args args; + + unionfs_lock_dentry(dentry); + bstart = dbstart(dentry); + + hidden_dentry = unionfs_lower_dentry(dentry); + + /* check if whiteout exists in this branch, i.e. lookup .wh.foo first */ + name = alloc_whname(dentry->d_name.name, dentry->d_name.len); + if (IS_ERR(name)) { + err = PTR_ERR(name); + goto out; + } + + whiteout_dentry = lookup_one_len(name, hidden_dentry->d_parent, + dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(whiteout_dentry)) { + err = PTR_ERR(whiteout_dentry); + goto out; + } + + if (!whiteout_dentry->d_inode) { + dput(whiteout_dentry); + whiteout_dentry = NULL; + } else { + hidden_parent_dentry = lock_parent(whiteout_dentry); + + /* found a.wh.foo entry, remove it then do vfs_mkdir */ + if (!(err = is_robranch_super(dentry->d_sb, bstart))) { + args.unlink.parent = hidden_parent_dentry->d_inode; + args.unlink.dentry = whiteout_dentry; + run_sioq(__unionfs_unlink, &args); + err = args.err; + } + dput(whiteout_dentry); + + unlock_dir(hidden_parent_dentry); + + if (err) { + /* exit if the error returned was NOT -EROFS */ + if (!IS_COPYUP_ERR(err)) + goto out; + bstart--; + } else + whiteout_unlinked = 1; + } + + for (bindex = bstart; bindex >= 0; bindex--) { + int i; + int bend = dbend(dentry); + + if (is_robranch_super(dentry->d_sb, bindex)) + continue; + + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) { + hidden_dentry = create_parents(parent, dentry, bindex); + if (!hidden_dentry || IS_ERR(hidden_dentry)) { + printk(KERN_DEBUG "hidden dentry NULL for " + "bindex = %d\n", bindex); + continue; + } + } + + hidden_parent_dentry = lock_parent(hidden_dentry); + + if (IS_ERR(hidden_parent_dentry)) { + err = PTR_ERR(hidden_parent_dentry); + goto out; + } + + err = vfs_mkdir(hidden_parent_dentry->d_inode, hidden_dentry, mode); + + unlock_dir(hidden_parent_dentry); + + /* did the mkdir suceed? */ + if (err) + break; + + for (i = bindex + 1; i < bend; i++) { + if (unionfs_lower_dentry_idx(dentry, i)) { + dput(unionfs_lower_dentry_idx(dentry, i)); + unionfs_set_lower_dentry_idx(dentry, i, NULL); + } + } + set_dbend(dentry, bindex); + + err = unionfs_interpose(dentry, parent->i_sb, 0); + if (!err) { + fsstack_copy_attr_times(parent, + hidden_parent_dentry->d_inode); + fsstack_copy_inode_size(parent, + hidden_parent_dentry->d_inode); + + /* update number of links on parent directory */ + parent->i_nlink = unionfs_get_nlinks(parent); + } + + err = make_dir_opaque(dentry, dbstart(dentry)); + if (err) { + printk(KERN_ERR "mkdir: error creating " + ".wh.__dir_opaque: %d\n", err); + goto out; + } + + /* we are done! */ + break; + } + +out: + if (!dentry->d_inode) + d_drop(dentry); + + kfree(name); + + unionfs_unlock_dentry(dentry); + return err; +} + +static int unionfs_mknod(struct inode *dir, struct dentry *dentry, int mode, + dev_t dev) +{ + int err = 0; + struct dentry *hidden_dentry = NULL, *whiteout_dentry = NULL; + struct dentry *hidden_parent_dentry = NULL; + int bindex = 0, bstart; + char *name = NULL; + int whiteout_unlinked = 0; + + unionfs_lock_dentry(dentry); + bstart = dbstart(dentry); + + hidden_dentry = unionfs_lower_dentry(dentry); + + /* check if whiteout exists in this branch, i.e. lookup .wh.foo first */ + name = alloc_whname(dentry->d_name.name, dentry->d_name.len); + if (IS_ERR(name)) { + err = PTR_ERR(name); + goto out; + } + + whiteout_dentry = lookup_one_len(name, hidden_dentry->d_parent, + dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(whiteout_dentry)) { + err = PTR_ERR(whiteout_dentry); + goto out; + } + + if (!whiteout_dentry->d_inode) { + dput(whiteout_dentry); + whiteout_dentry = NULL; + } else { + /* found .wh.foo, unlink it */ + hidden_parent_dentry = lock_parent(whiteout_dentry); + + /* found a.wh.foo entry, remove it then do vfs_mkdir */ + if (!(err = is_robranch_super(dentry->d_sb, bstart))) + err = vfs_unlink(hidden_parent_dentry->d_inode, + whiteout_dentry); + dput(whiteout_dentry); + + unlock_dir(hidden_parent_dentry); + + if (err) { + if (!IS_COPYUP_ERR(err)) + goto out; + + bstart--; + } else + whiteout_unlinked = 1; + } + + for (bindex = bstart; bindex >= 0; bindex--) { + if (is_robranch_super(dentry->d_sb, bindex)) + continue; + + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) { + hidden_dentry = create_parents(dir, dentry, bindex); + if (IS_ERR(hidden_dentry)) { + printk(KERN_DEBUG + "failed to create parents on %d, err = %ld\n", + bindex, PTR_ERR(hidden_dentry)); + continue; + } + } + + hidden_parent_dentry = lock_parent(hidden_dentry); + if (IS_ERR(hidden_parent_dentry)) { + err = PTR_ERR(hidden_parent_dentry); + goto out; + } + + err = vfs_mknod(hidden_parent_dentry->d_inode, + hidden_dentry, mode, dev); + + if (err) { + unlock_dir(hidden_parent_dentry); + break; + } + + err = unionfs_interpose(dentry, dir->i_sb, 0); + if (!err) { + fsstack_copy_attr_times(dir, + hidden_parent_dentry->d_inode); + fsstack_copy_inode_size(dir, + hidden_parent_dentry->d_inode); + /* update number of links on parent directory */ + dir->i_nlink = unionfs_get_nlinks(dir); + } + unlock_dir(hidden_parent_dentry); + + break; + } + +out: + if (!dentry->d_inode) + d_drop(dentry); + + kfree(name); + + unionfs_unlock_dentry(dentry); + return err; +} + +static int unionfs_readlink(struct dentry *dentry, char __user * buf, + int bufsiz) +{ + int err; + struct dentry *hidden_dentry; + + unionfs_lock_dentry(dentry); + hidden_dentry = unionfs_lower_dentry(dentry); + + if (!hidden_dentry->d_inode->i_op || + !hidden_dentry->d_inode->i_op->readlink) { + err = -EINVAL; + goto out; + } + + err = hidden_dentry->d_inode->i_op->readlink(hidden_dentry, buf, bufsiz); + if (err > 0) + fsstack_copy_attr_atime(dentry->d_inode, hidden_dentry->d_inode); + +out: + unionfs_unlock_dentry(dentry); + return err; +} + +/* We don't lock the dentry here, because readlink does the heavy lifting. */ +static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + char *buf; + int len = PAGE_SIZE, err; + mm_segment_t old_fs; + + /* This is freed by the put_link method assuming a successful call. */ + buf = kmalloc(len, GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto out; + } + + /* read the symlink, and then we will follow it */ + old_fs = get_fs(); + set_fs(KERNEL_DS); + err = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); + set_fs(old_fs); + if (err < 0) { + kfree(buf); + buf = NULL; + goto out; + } + buf[err] = 0; + nd_set_link(nd, buf); + err = 0; + +out: + return ERR_PTR(err); +} + +static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd, + void *cookie) +{ + kfree(nd_get_link(nd)); +} + +/* Basically copied from the kernel vfs permission(), but we've changed + * the following: + * (1) the IS_RDONLY check is skipped, and + * (2) if you set the mount option `mode=nfsro', we assume that -EACCES + * means that the export is read-only and we should check standard Unix + * permissions. This means that NFS ACL checks (or other advanced + * permission features) are bypassed. Note however, that we do call + * security_inode_permission, and therefore security inside SELinux, etc. + * are performed. + */ +static int inode_permission(struct inode *inode, int mask, struct nameidata *nd, + int bindex) +{ + int retval, submask; + + if (mask & MAY_WRITE) { + /* The first branch is allowed to be really readonly. */ + if (bindex == 0) { + umode_t mode = inode->i_mode; + if (IS_RDONLY(inode) && + (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) + return -EROFS; + } + /* + * Nobody gets write access to an immutable file. + */ + if (IS_IMMUTABLE(inode)) + return -EACCES; + } + + /* Ordinary permission routines do not understand MAY_APPEND. */ + submask = mask & ~MAY_APPEND; + if (inode->i_op && inode->i_op->permission) { + retval = inode->i_op->permission(inode, submask, nd); + if ((retval == -EACCES) && (submask & MAY_WRITE) && + (!strcmp("nfs", (inode)->i_sb->s_type->name)) && + (nd) && (nd->mnt) && (nd->mnt->mnt_sb) && + (branchperms(nd->mnt->mnt_sb, bindex) & MAY_NFSRO)) { + retval = generic_permission(inode, submask, NULL); + } + } else + retval = generic_permission(inode, submask, NULL); + + if (retval && retval != -EROFS) /* ignore EROFS */ + return retval; + + retval = security_inode_permission(inode, mask, nd); + return ((retval == -EROFS) ? 0 : retval); /* ignore EROFS */ +} + +static int unionfs_permission(struct inode *inode, int mask, + struct nameidata *nd) +{ + struct inode *hidden_inode = NULL; + int err = 0; + int bindex, bstart, bend; + const int is_file = !S_ISDIR(inode->i_mode); + const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ); + + bstart = ibstart(inode); + bend = ibend(inode); + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_inode = unionfs_lower_inode_idx(inode, bindex); + if (!hidden_inode) + continue; + + /* check the condition for D-F-D underlying files/directories, + * we dont have to check for files, if we are checking for + * directories. + */ + if (!is_file && !S_ISDIR(hidden_inode->i_mode)) + continue; + + /* We use our own special version of permission, such that + * only the first branch returns -EROFS. + */ + err = inode_permission(hidden_inode, mask, nd, bindex); + + /* The permissions are an intersection of the overall directory + * permissions, so we fail if one fails. + */ + if (err) + goto out; + + /* only the leftmost file matters. */ + if (is_file || write_mask) { + if (is_file && write_mask) { + err = get_write_access(hidden_inode); + if (!err) + put_write_access(hidden_inode); + } + break; + } + } + +out: + return err; +} + +static int unionfs_setattr(struct dentry *dentry, struct iattr *ia) +{ + int err = 0; + struct dentry *hidden_dentry; + struct inode *inode = NULL; + struct inode *hidden_inode = NULL; + int bstart, bend, bindex; + int i; + int copyup = 0; + + unionfs_lock_dentry(dentry); + bstart = dbstart(dentry); + bend = dbend(dentry); + inode = dentry->d_inode; + + for (bindex = bstart; (bindex <= bend) || (bindex == bstart); bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) + continue; + BUG_ON(hidden_dentry->d_inode == NULL); + + /* If the file is on a read only branch */ + if (is_robranch_super(dentry->d_sb, bindex) + || IS_RDONLY(hidden_dentry->d_inode)) { + if (copyup || (bindex != bstart)) + continue; + /* Only if its the leftmost file, copyup the file */ + for (i = bstart - 1; i >= 0; i--) { + loff_t size = dentry->d_inode->i_size; + if (ia->ia_valid & ATTR_SIZE) + size = ia->ia_size; + err = copyup_dentry(dentry->d_parent->d_inode, + dentry, bstart, i, NULL, + size); + + if (!err) { + copyup = 1; + hidden_dentry = unionfs_lower_dentry(dentry); + break; + } + /* if error is in the leftmost branch, pass it up */ + if (i == 0) + goto out; + } + + } + err = notify_change(hidden_dentry, ia); + if (err) + goto out; + break; + } + + /* get the size from the first hidden inode */ + hidden_inode = unionfs_lower_inode(dentry->d_inode); + fsstack_copy_attr_all(inode, hidden_inode, unionfs_get_nlinks); + fsstack_copy_inode_size(inode, hidden_inode); + +out: + unionfs_unlock_dentry(dentry); + return err; +} + +struct inode_operations unionfs_symlink_iops = { + .readlink = unionfs_readlink, + .permission = unionfs_permission, + .follow_link = unionfs_follow_link, + .setattr = unionfs_setattr, + .put_link = unionfs_put_link, +}; + +struct inode_operations unionfs_dir_iops = { + .create = unionfs_create, + .lookup = unionfs_lookup, + .link = unionfs_link, + .unlink = unionfs_unlink, + .symlink = unionfs_symlink, + .mkdir = unionfs_mkdir, + .rmdir = unionfs_rmdir, + .mknod = unionfs_mknod, + .rename = unionfs_rename, + .permission = unionfs_permission, + .setattr = unionfs_setattr, +#ifdef CONFIG_UNION_FS_XATTR + .setxattr = unionfs_setxattr, + .getxattr = unionfs_getxattr, + .removexattr = unionfs_removexattr, + .listxattr = unionfs_listxattr, +#endif +}; + +struct inode_operations unionfs_main_iops = { + .permission = unionfs_permission, + .setattr = unionfs_setattr, +#ifdef CONFIG_UNION_FS_XATTR + .setxattr = unionfs_setxattr, + .getxattr = unionfs_getxattr, + .removexattr = unionfs_removexattr, + .listxattr = unionfs_listxattr, +#endif +}; + diff --git a/fs/unionfs/lookup.c b/fs/unionfs/lookup.c new file mode 100644 index 0000000..df929e9 --- /dev/null +++ b/fs/unionfs/lookup.c @@ -0,0 +1,515 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* is the filename valid == !(whiteout for a file or opaque dir marker) */ +static int is_validname(const char *name) +{ + if (!strncmp(name, UNIONFS_WHPFX, UNIONFS_WHLEN)) + return 0; + if (!strncmp(name, UNIONFS_DIR_OPAQUE_NAME, + sizeof(UNIONFS_DIR_OPAQUE_NAME) - 1)) + return 0; + return 1; +} + +/* The rest of these are utility functions for lookup. */ +static int is_opaque_dir(struct dentry *dentry, int bindex) +{ + int err = 0; + struct dentry *hidden_dentry; + struct dentry *wh_hidden_dentry; + struct inode *hidden_inode; + struct sioq_args args; + + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + hidden_inode = hidden_dentry->d_inode; + + BUG_ON(!S_ISDIR(hidden_inode->i_mode)); + + mutex_lock(&hidden_inode->i_mutex); + + if (!permission(hidden_inode, MAY_EXEC, NULL)) + wh_hidden_dentry = lookup_one_len(UNIONFS_DIR_OPAQUE, hidden_dentry, + sizeof(UNIONFS_DIR_OPAQUE) - 1); + else { + args.is_opaque.dentry = hidden_dentry; + run_sioq(__is_opaque_dir, &args); + wh_hidden_dentry = args.ret; + } + + mutex_unlock(&hidden_inode->i_mutex); + + if (IS_ERR(wh_hidden_dentry)) { + err = PTR_ERR(wh_hidden_dentry); + goto out; + } + + /* This is an opaque dir iff wh_hidden_dentry is positive */ + err = !!wh_hidden_dentry->d_inode; + + dput(wh_hidden_dentry); +out: + return err; +} + +struct dentry *unionfs_lookup_backend(struct dentry *dentry, struct nameidata *nd, + int lookupmode) +{ + int err = 0; + struct dentry *hidden_dentry = NULL; + struct dentry *wh_hidden_dentry = NULL; + struct dentry *hidden_dir_dentry = NULL; + struct dentry *parent_dentry = NULL; + int bindex, bstart, bend, bopaque; + int dentry_count = 0; /* Number of positive dentries. */ + int first_dentry_offset = -1; + struct dentry *first_hidden_dentry = NULL; + struct vfsmount *first_hidden_mnt = NULL; + int locked_parent = 0; + int locked_child = 0; + + int opaque; + char *whname = NULL; + const char *name; + int namelen; + + /* We should already have a lock on this dentry in the case of a + * partial lookup, or a revalidation. Otherwise it is returned from + * new_dentry_private_data already locked. + */ + if (lookupmode == INTERPOSE_PARTIAL || lookupmode == INTERPOSE_REVAL || + lookupmode == INTERPOSE_REVAL_NEG) + verify_locked(dentry); + else { + BUG_ON(UNIONFS_D(dentry) != NULL); + locked_child = 1; + } + if (lookupmode != INTERPOSE_PARTIAL) + if ((err = new_dentry_private_data(dentry))) + goto out; + /* must initialize dentry operations */ + dentry->d_op = &unionfs_dops; + + parent_dentry = dget_parent(dentry); + /* We never partial lookup the root directory. */ + if (parent_dentry != dentry) { + unionfs_lock_dentry(parent_dentry); + locked_parent = 1; + } else { + dput(parent_dentry); + parent_dentry = NULL; + goto out; + } + + name = dentry->d_name.name; + namelen = dentry->d_name.len; + + /* No dentries should get created for possible whiteout names. */ + if (!is_validname(name)) { + err = -EPERM; + goto out_free; + } + + /* Now start the actual lookup procedure. */ + bstart = dbstart(parent_dentry); + bend = dbend(parent_dentry); + bopaque = dbopaque(parent_dentry); + BUG_ON(bstart < 0); + + /* It would be ideal if we could convert partial lookups to only have + * to do this work when they really need to. It could probably improve + * performance quite a bit, and maybe simplify the rest of the code. + */ + if (lookupmode == INTERPOSE_PARTIAL) { + bstart++; + if ((bopaque != -1) && (bopaque < bend)) + bend = bopaque; + } + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (lookupmode == INTERPOSE_PARTIAL && hidden_dentry) + continue; + BUG_ON(hidden_dentry != NULL); + + hidden_dir_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex); + + /* if the parent hidden dentry does not exist skip this */ + if (!(hidden_dir_dentry && hidden_dir_dentry->d_inode)) + continue; + + /* also skip it if the parent isn't a directory. */ + if (!S_ISDIR(hidden_dir_dentry->d_inode->i_mode)) + continue; + + /* Reuse the whiteout name because its value doesn't change. */ + if (!whname) { + whname = alloc_whname(name, namelen); + if (IS_ERR(whname)) { + err = PTR_ERR(whname); + goto out_free; + } + } + + /* check if whiteout exists in this branch: lookup .wh.foo */ + wh_hidden_dentry = lookup_one_len(whname, hidden_dir_dentry, + namelen + UNIONFS_WHLEN); + if (IS_ERR(wh_hidden_dentry)) { + dput(first_hidden_dentry); + mntput(first_hidden_mnt); + err = PTR_ERR(wh_hidden_dentry); + goto out_free; + } + + if (wh_hidden_dentry->d_inode) { + /* We found a whiteout so lets give up. */ + if (S_ISREG(wh_hidden_dentry->d_inode->i_mode)) { + set_dbend(dentry, bindex); + set_dbopaque(dentry, bindex); + dput(wh_hidden_dentry); + break; + } + err = -EIO; + printk(KERN_NOTICE "EIO: Invalid whiteout entry type" + " %d.\n", wh_hidden_dentry->d_inode->i_mode); + dput(wh_hidden_dentry); + dput(first_hidden_dentry); + mntput(first_hidden_mnt); + goto out_free; + } + + dput(wh_hidden_dentry); + wh_hidden_dentry = NULL; + + /* Now do regular lookup; lookup foo */ + nd->dentry = unionfs_lower_dentry_idx(dentry, bindex); + /* FIXME: fix following line for mount point crossing */ + nd->mnt = unionfs_lower_mnt_idx(parent_dentry, bindex); + + hidden_dentry = lookup_one_len_nd(name, hidden_dir_dentry, + namelen, nd); + if (IS_ERR(hidden_dentry)) { + dput(first_hidden_dentry); + mntput(first_hidden_mnt); + err = PTR_ERR(hidden_dentry); + goto out_free; + } + + /* Store the first negative dentry specially, because if they + * are all negative we need this for future creates. + */ + if (!hidden_dentry->d_inode) { + if (!first_hidden_dentry && (dbstart(dentry) == -1)) { + first_hidden_dentry = hidden_dentry; + /* FIXME: following line needs to be changed + * to allow mountpoint crossing + */ + first_hidden_mnt = mntget( + unionfs_lower_mnt_idx(parent_dentry, + bindex)); + first_dentry_offset = bindex; + } else + dput(hidden_dentry); + + continue; + } + + /* number of positive dentries */ + dentry_count++; + + /* store underlying dentry */ + if (dbstart(dentry) == -1) + set_dbstart(dentry, bindex); + unionfs_set_lower_dentry_idx(dentry, bindex, hidden_dentry); + /* FIXME: the following line needs to get fixed to allow + * mountpoint crossing + */ + unionfs_set_lower_mnt_idx(dentry, bindex, + mntget(unionfs_lower_mnt_idx(parent_dentry, bindex))); + set_dbend(dentry, bindex); + + /* update parent directory's atime with the bindex */ + fsstack_copy_attr_atime(parent_dentry->d_inode, + hidden_dir_dentry->d_inode); + + /* We terminate file lookups here. */ + if (!S_ISDIR(hidden_dentry->d_inode->i_mode)) { + if (lookupmode == INTERPOSE_PARTIAL) + continue; + if (dentry_count == 1) + goto out_positive; + /* This can only happen with mixed D-*-F-* */ + BUG_ON(!S_ISDIR(unionfs_lower_dentry(dentry)->d_inode->i_mode)); + continue; + } + + opaque = is_opaque_dir(dentry, bindex); + if (opaque < 0) { + dput(first_hidden_dentry); + mntput(first_hidden_mnt); + err = opaque; + goto out_free; + } else if (opaque) { + set_dbend(dentry, bindex); + set_dbopaque(dentry, bindex); + break; + } + } + + if (dentry_count) + goto out_positive; + else + goto out_negative; + +out_negative: + if (lookupmode == INTERPOSE_PARTIAL) + goto out; + + /* If we've only got negative dentries, then use the leftmost one. */ + if (lookupmode == INTERPOSE_REVAL) { + if (dentry->d_inode) + UNIONFS_I(dentry->d_inode)->stale = 1; + + goto out; + } + /* This should only happen if we found a whiteout. */ + if (first_dentry_offset == -1) { + nd->dentry = dentry; + /* FIXME: fix following line for mount point crossing */ + nd->mnt = unionfs_lower_mnt_idx(parent_dentry, bindex); + + first_hidden_dentry = lookup_one_len_nd(name, hidden_dir_dentry, + namelen, nd); + first_dentry_offset = bindex; + if (IS_ERR(first_hidden_dentry)) { + err = PTR_ERR(first_hidden_dentry); + goto out; + } + + /* FIXME: the following line needs to be changed to allow + * mountpoint crossing + */ + first_hidden_mnt = mntget(unionfs_lower_mnt_idx(dentry, bindex)); + } + unionfs_set_lower_dentry_idx(dentry, first_dentry_offset, first_hidden_dentry); + unionfs_set_lower_mnt_idx(dentry, first_dentry_offset, first_hidden_mnt); + set_dbstart(dentry, first_dentry_offset); + set_dbend(dentry, first_dentry_offset); + + if (lookupmode == INTERPOSE_REVAL_NEG) + BUG_ON(dentry->d_inode != NULL); + else + d_add(dentry, NULL); + goto out; + +/* This part of the code is for positive dentries. */ +out_positive: + BUG_ON(dentry_count <= 0); + + /* If we're holding onto the first negative dentry & corresponding + * vfsmount - throw it out. + */ + dput(first_hidden_dentry); + mntput(first_hidden_mnt); + + /* Partial lookups need to reinterpose, or throw away older negs. */ + if (lookupmode == INTERPOSE_PARTIAL) { + if (dentry->d_inode) { + unionfs_reinterpose(dentry); + goto out; + } + + /* This somehow turned positive, so it is as if we had a + * negative revalidation. + */ + lookupmode = INTERPOSE_REVAL_NEG; + + update_bstart(dentry); + bstart = dbstart(dentry); + bend = dbend(dentry); + } + + err = unionfs_interpose(dentry, dentry->d_sb, lookupmode); + if (err) + goto out_drop; + + goto out; + +out_drop: + d_drop(dentry); + +out_free: + /* should dput all the underlying dentries on error condition */ + bstart = dbstart(dentry); + if (bstart >= 0) { + bend = dbend(dentry); + for (bindex = bstart; bindex <= bend; bindex++) { + dput(unionfs_lower_dentry_idx(dentry, bindex)); + mntput(unionfs_lower_mnt_idx(dentry, bindex)); + } + } + kfree(UNIONFS_D(dentry)->lower_paths); + UNIONFS_D(dentry)->lower_paths = NULL; + set_dbstart(dentry, -1); + set_dbend(dentry, -1); + +out: + if (!err && UNIONFS_D(dentry)) { + BUG_ON(dbend(dentry) > UNIONFS_D(dentry)->bcount); + BUG_ON(dbend(dentry) > sbmax(dentry->d_sb)); + BUG_ON(dbstart(dentry) < 0); + } + kfree(whname); + if (locked_parent) + unionfs_unlock_dentry(parent_dentry); + dput(parent_dentry); + if (locked_child) + unionfs_unlock_dentry(dentry); + return ERR_PTR(err); +} + +/* This is a utility function that fills in a unionfs dentry.*/ +int unionfs_partial_lookup(struct dentry *dentry) +{ + struct dentry *tmp; + struct nameidata nd = { .flags = 0 }; + + tmp = unionfs_lookup_backend(dentry, &nd, INTERPOSE_PARTIAL); + if (!tmp) + return 0; + if (IS_ERR(tmp)) + return PTR_ERR(tmp); + /* need to change the interface */ + BUG_ON(tmp != dentry); + return -ENOSYS; +} + +/* The dentry cache is just so we have properly sized dentries. */ +static struct kmem_cache *unionfs_dentry_cachep; +int unionfs_init_dentry_cache(void) +{ + unionfs_dentry_cachep = kmem_cache_create("unionfs_dentry", + sizeof(struct unionfs_dentry_info), 0, + SLAB_RECLAIM_ACCOUNT, NULL, NULL); + + return (unionfs_dentry_cachep ? 0 : -ENOMEM); +} + +void unionfs_destroy_dentry_cache(void) +{ + if (unionfs_dentry_cachep) + kmem_cache_destroy(unionfs_dentry_cachep); +} + +void free_dentry_private_data(struct unionfs_dentry_info *udi) +{ + if (!udi) + return; + kmem_cache_free(unionfs_dentry_cachep, udi); +} + +/* allocate new dentry private data, free old one if necessary */ +int new_dentry_private_data(struct dentry *dentry) +{ + int newsize; + int oldsize = 0; + struct unionfs_dentry_info *info = UNIONFS_D(dentry); + + spin_lock(&dentry->d_lock); + if (!info) { + dentry->d_fsdata = kmem_cache_alloc(unionfs_dentry_cachep, + GFP_ATOMIC); + info = UNIONFS_D(dentry); + + if (!info) + goto out; + + mutex_init(&info->lock); + mutex_lock(&info->lock); + + info->lower_paths = NULL; + } else + oldsize = sizeof(struct path) * info->bcount; + + info->bstart = -1; + info->bend = -1; + info->bopaque = -1; + info->bcount = sbmax(dentry->d_sb); + atomic_set(&info->generation, + atomic_read(&UNIONFS_SB(dentry->d_sb)->generation)); + newsize = sizeof(struct path) * sbmax(dentry->d_sb); + + /* Don't reallocate when we already have enough space. */ + /* It would be ideal if we could actually use the slab macros to + * determine what our object sizes is, but those are not exported. + */ + if (oldsize) { + int minsize = malloc_sizes[0].cs_size; + + if (!newsize || ((oldsize < newsize) && (newsize > minsize))) { + kfree(info->lower_paths); + info->lower_paths = NULL; + } + } + + if (!info->lower_paths && newsize) { + info->lower_paths = kmalloc(newsize, GFP_ATOMIC); + if (!info->lower_paths) + goto out_free; + } + + memset(info->lower_paths, 0, (oldsize > newsize ? oldsize : newsize)); + + spin_unlock(&dentry->d_lock); + return 0; + +out_free: + kfree(info->lower_paths); + +out: + free_dentry_private_data(info); + dentry->d_fsdata = NULL; + spin_unlock(&dentry->d_lock); + return -ENOMEM; +} + +/* scan through the lower dentry objects, and set bstart to reflect the + * starting branch + */ +void update_bstart(struct dentry *dentry) +{ + int bindex; + int bstart = dbstart(dentry); + int bend = dbend(dentry); + struct dentry *hidden_dentry; + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) + continue; + if (hidden_dentry->d_inode) { + set_dbstart(dentry, bindex); + break; + } + dput(hidden_dentry); + unionfs_set_lower_dentry_idx(dentry, bindex, NULL); + } +} + diff --git a/fs/unionfs/main.c b/fs/unionfs/main.c new file mode 100644 index 0000000..ca7ee26 --- /dev/null +++ b/fs/unionfs/main.c @@ -0,0 +1,687 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" +#include +#include + +/* sb we pass is unionfs's super_block */ +int unionfs_interpose(struct dentry *dentry, struct super_block *sb, int flag) +{ + struct inode *hidden_inode; + struct dentry *hidden_dentry; + int err = 0; + struct inode *inode; + int is_negative_dentry = 1; + int bindex, bstart, bend; + + verify_locked(dentry); + + bstart = dbstart(dentry); + bend = dbend(dentry); + + /* Make sure that we didn't get a negative dentry. */ + for (bindex = bstart; bindex <= bend; bindex++) { + if (unionfs_lower_dentry_idx(dentry, bindex) && + unionfs_lower_dentry_idx(dentry, bindex)->d_inode) { + is_negative_dentry = 0; + break; + } + } + BUG_ON(is_negative_dentry); + + /* We allocate our new inode below, by calling iget. + * iget will call our read_inode which will initialize some + * of the new inode's fields + */ + + /* On revalidate we've already got our own inode and just need + * to fix it up. + */ + if (flag == INTERPOSE_REVAL) { + inode = dentry->d_inode; + UNIONFS_I(inode)->bstart = -1; + UNIONFS_I(inode)->bend = -1; + atomic_set(&UNIONFS_I(inode)->generation, + atomic_read(&UNIONFS_SB(sb)->generation)); + + UNIONFS_I(inode)->lower_inodes = + kcalloc(sbmax(sb), sizeof(struct inode *), GFP_KERNEL); + if (!UNIONFS_I(inode)->lower_inodes) { + err = -ENOMEM; + goto out; + } + mutex_lock(&inode->i_mutex); + } else { + ino_t ino; + /* get unique inode number for unionfs */ + ino = iunique(sb, UNIONFS_ROOT_INO); + + inode = iget(sb, ino); + if (!inode) { + err = -EACCES; /* should be impossible??? */ + goto out; + } + + mutex_lock(&inode->i_mutex); + if (atomic_read(&inode->i_count) > 1) + goto skip; + } + + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) { + unionfs_set_lower_inode_idx(inode, bindex, NULL); + continue; + } + + /* Initialize the hidden inode to the new hidden inode. */ + if (!hidden_dentry->d_inode) + continue; + + unionfs_set_lower_inode_idx(inode, bindex, + igrab(hidden_dentry->d_inode)); + } + + ibstart(inode) = dbstart(dentry); + ibend(inode) = dbend(dentry); + + /* Use attributes from the first branch. */ + hidden_inode = unionfs_lower_inode(inode); + + /* Use different set of inode ops for symlinks & directories */ + if (S_ISLNK(hidden_inode->i_mode)) + inode->i_op = &unionfs_symlink_iops; + else if (S_ISDIR(hidden_inode->i_mode)) + inode->i_op = &unionfs_dir_iops; + + /* Use different set of file ops for directories */ + if (S_ISDIR(hidden_inode->i_mode)) + inode->i_fop = &unionfs_dir_fops; + + /* properly initialize special inodes */ + if (S_ISBLK(hidden_inode->i_mode) || S_ISCHR(hidden_inode->i_mode) || + S_ISFIFO(hidden_inode->i_mode) || S_ISSOCK(hidden_inode->i_mode)) + init_special_inode(inode, hidden_inode->i_mode, + hidden_inode->i_rdev); + /* Fix our inode's address operations to that of the lower inode + * (Unionfs is FiST-Lite) + */ + if (inode->i_mapping->a_ops != hidden_inode->i_mapping->a_ops) + inode->i_mapping->a_ops = hidden_inode->i_mapping->a_ops; + + /* all well, copy inode attributes */ + fsstack_copy_attr_all(inode, hidden_inode, unionfs_get_nlinks); + fsstack_copy_inode_size(inode, hidden_inode); + +skip: + /* only (our) lookup wants to do a d_add */ + switch (flag) { + case INTERPOSE_DEFAULT: + case INTERPOSE_REVAL_NEG: + d_instantiate(dentry, inode); + break; + case INTERPOSE_LOOKUP: + err = PTR_ERR(d_splice_alias(inode, dentry)); + break; + case INTERPOSE_REVAL: + /* Do nothing. */ + break; + default: + printk(KERN_ERR "Invalid interpose flag passed!"); + BUG(); + } + + mutex_unlock(&inode->i_mutex); + +out: + return err; +} + +void unionfs_reinterpose(struct dentry *dentry) +{ + struct dentry *hidden_dentry; + struct inode *inode; + int bindex, bstart, bend; + + verify_locked(dentry); + + /* This is pre-allocated inode */ + inode = dentry->d_inode; + + bstart = dbstart(dentry); + bend = dbend(dentry); + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) + continue; + + if (!hidden_dentry->d_inode) + continue; + if (unionfs_lower_inode_idx(inode, bindex)) + continue; + unionfs_set_lower_inode_idx(inode, bindex, + igrab(hidden_dentry->d_inode)); + } + ibstart(inode) = dbstart(dentry); + ibend(inode) = dbend(dentry); +} + +/* make sure the branch we just looked up (nd) makes sense: + * + * 1) we're not trying to stack unionfs on top of unionfs + * 2) it exists + * 3) is a directory + */ +static int check_branch(struct nameidata *nd) +{ + if (!strcmp(nd->dentry->d_sb->s_type->name, "unionfs")) + return -EINVAL; + if (!nd->dentry->d_inode) + return -ENOENT; + if (!S_ISDIR(nd->dentry->d_inode->i_mode)) + return -ENOTDIR; + return 0; +} + +/* checks if two hidden_dentries have overlapping branches */ +static int is_branch_overlap(struct dentry *dent1, struct dentry *dent2) +{ + struct dentry *dent = NULL; + + dent = dent1; + while ((dent != dent2) && (dent->d_parent != dent)) + dent = dent->d_parent; + + if (dent == dent2) + return 1; + + dent = dent2; + while ((dent != dent1) && (dent->d_parent != dent)) + dent = dent->d_parent; + + return (dent == dent1); +} + +/* parse branch mode */ +static int parse_branch_mode(char *name) +{ + int perms; + int l = strlen(name); + if (!strcmp(name + l - 3, "=ro")) { + perms = MAY_READ; + name[l - 3] = '\0'; + } else if (!strcmp(name + l - 3, "=rw")) { + perms = MAY_READ | MAY_WRITE; + name[l - 3] = '\0'; + } else + perms = MAY_READ | MAY_WRITE; + + return perms; +} + +/* parse the dirs= mount argument */ +static int parse_dirs_option(struct super_block *sb, struct unionfs_dentry_info + *hidden_root_info, char *options) +{ + struct nameidata nd; + char *name; + int err = 0; + int branches = 1; + int bindex = 0; + int i = 0; + int j = 0; + + struct dentry *dent1; + struct dentry *dent2; + + if (options[0] == '\0') { + printk(KERN_WARNING "unionfs: no branches specified\n"); + err = -EINVAL; + goto out; + } + + /* Each colon means we have a separator, this is really just a rough + * guess, since strsep will handle empty fields for us. + */ + for (i = 0; options[i]; i++) + if (options[i] == ':') + branches++; + + /* allocate space for underlying pointers to hidden dentry */ + UNIONFS_SB(sb)->data = kcalloc(branches, + sizeof(struct unionfs_data), GFP_KERNEL); + if (!UNIONFS_SB(sb)->data) { + err = -ENOMEM; + goto out; + } + + hidden_root_info->lower_paths = kcalloc(branches, + sizeof(struct path), GFP_KERNEL); + if (!hidden_root_info->lower_paths) { + err = -ENOMEM; + goto out; + } + + /* now parsing the string b1:b2=rw:b3=ro:b4 */ + branches = 0; + while ((name = strsep(&options, ":")) != NULL) { + int perms; + + if (!*name) + continue; + + branches++; + + /* strip off =rw or =ro if it is specified. */ + perms = parse_branch_mode(name); + if (!bindex && !(perms & MAY_WRITE)) { + err = -EINVAL; + goto out; + } + + err = path_lookup(name, LOOKUP_FOLLOW, &nd); + if (err) { + printk(KERN_WARNING "unionfs: error accessing " + "hidden directory '%s' (error %d)\n", name, err); + goto out; + } + + if ((err = check_branch(&nd))) { + printk(KERN_WARNING "unionfs: hidden directory " + "'%s' is not a valid branch\n", name); + path_release(&nd); + goto out; + } + + hidden_root_info->lower_paths[bindex].dentry = nd.dentry; + hidden_root_info->lower_paths[bindex].mnt = nd.mnt; + + set_branchperms(sb, bindex, perms); + set_branch_count(sb, bindex, 0); + + if (hidden_root_info->bstart < 0) + hidden_root_info->bstart = bindex; + hidden_root_info->bend = bindex; + bindex++; + } + + if (branches == 0) { + printk(KERN_WARNING "unionfs: no branches specified\n"); + err = -EINVAL; + goto out; + } + + BUG_ON(branches != (hidden_root_info->bend + 1)); + + /* ensure that no overlaps exist in the branches */ + for (i = 0; i < branches; i++) { + for (j = i + 1; j < branches; j++) { + dent1 = hidden_root_info->lower_paths[i].dentry; + dent2 = hidden_root_info->lower_paths[j].dentry; + + if (is_branch_overlap(dent1, dent2)) { + printk(KERN_WARNING "unionfs: branches %d and " + "%d overlap\n", i, j); + err = -EINVAL; + goto out; + } + } + } + +out: + if (err) { + for (i = 0; i < branches; i++) + if (hidden_root_info->lower_paths[i].dentry) { + dput(hidden_root_info->lower_paths[i].dentry); + mntput(hidden_root_info->lower_paths[i].mnt); + } + + kfree(hidden_root_info->lower_paths); + kfree(UNIONFS_SB(sb)->data); + + /* MUST clear the pointers to prevent potential double free if + * the caller dies later on + */ + hidden_root_info->lower_paths = NULL; + UNIONFS_SB(sb)->data = NULL; + } + return err; +} + +/* + * Parse mount options. See the manual page for usage instructions. + * + * Returns the dentry object of the lower-level (hidden) directory; + * We want to mount our stackable file system on top of that hidden directory. + */ +static struct unionfs_dentry_info *unionfs_parse_options(struct super_block *sb, + char *options) +{ + struct unionfs_dentry_info *hidden_root_info; + char *optname; + int err = 0; + int bindex; + int dirsfound = 0; + + /* allocate private data area */ + err = -ENOMEM; + hidden_root_info = + kzalloc(sizeof(struct unionfs_dentry_info), GFP_KERNEL); + if (!hidden_root_info) + goto out_error; + hidden_root_info->bstart = -1; + hidden_root_info->bend = -1; + hidden_root_info->bopaque = -1; + + while ((optname = strsep(&options, ",")) != NULL) { + char *optarg; + char *endptr; + int intval; + + if (!*optname) + continue; + + optarg = strchr(optname, '='); + if (optarg) + *optarg++ = '\0'; + + /* All of our options take an argument now. Insert ones that + * don't, above this check. + */ + if (!optarg) { + printk("unionfs: %s requires an argument.\n", optname); + err = -EINVAL; + goto out_error; + } + + if (!strcmp("dirs", optname)) { + if (++dirsfound > 1) { + printk(KERN_WARNING + "unionfs: multiple dirs specified\n"); + err = -EINVAL; + goto out_error; + } + err = parse_dirs_option(sb, hidden_root_info, optarg); + if (err) + goto out_error; + continue; + } + + /* All of these options require an integer argument. */ + intval = simple_strtoul(optarg, &endptr, 0); + if (*endptr) { + printk(KERN_WARNING + "unionfs: invalid %s option '%s'\n", + optname, optarg); + err = -EINVAL; + goto out_error; + } + + err = -EINVAL; + printk(KERN_WARNING + "unionfs: unrecognized option '%s'\n", optname); + goto out_error; + } + if (dirsfound != 1) { + printk(KERN_WARNING "unionfs: dirs option required\n"); + err = -EINVAL; + goto out_error; + } + goto out; + +out_error: + if (hidden_root_info && hidden_root_info->lower_paths) { + for (bindex = hidden_root_info->bstart; + bindex >= 0 && bindex <= hidden_root_info->bend; + bindex++) { + struct dentry *d; + struct vfsmount *m; + + d = hidden_root_info->lower_paths[bindex].dentry; + m = hidden_root_info->lower_paths[bindex].mnt; + + dput(d); + + if (m) + mntput(m); + } + } + + kfree(hidden_root_info->lower_paths); + kfree(hidden_root_info); + + kfree(UNIONFS_SB(sb)->data); + UNIONFS_SB(sb)->data = NULL; + + hidden_root_info = ERR_PTR(err); +out: + return hidden_root_info; +} + +/* our custom d_alloc_root workalike + * + * we can't use d_alloc_root if we want to use our own interpose function + * unchanged, so we simply call our own "fake" d_alloc_root + */ +static struct dentry *unionfs_d_alloc_root(struct super_block *sb) +{ + struct dentry *ret = NULL; + + if (sb) { + static const struct qstr name = {.name = "/",.len = 1 }; + + ret = d_alloc(NULL, &name); + if (ret) { + ret->d_op = &unionfs_dops; + ret->d_sb = sb; + ret->d_parent = ret; + } + } + return ret; +} + +static int unionfs_read_super(struct super_block *sb, void *raw_data, + int silent) +{ + int err = 0; + + struct unionfs_dentry_info *hidden_root_info = NULL; + int bindex, bstart, bend; + + if (!raw_data) { + printk(KERN_WARNING + "unionfs_read_super: missing data argument\n"); + err = -EINVAL; + goto out; + } + + /* Allocate superblock private data */ + sb->s_fs_info = kzalloc(sizeof(struct unionfs_sb_info), GFP_KERNEL); + if (!UNIONFS_SB(sb)) { + printk(KERN_WARNING "%s: out of memory\n", __FUNCTION__); + err = -ENOMEM; + goto out; + } + + UNIONFS_SB(sb)->bend = -1; + atomic_set(&UNIONFS_SB(sb)->generation, 1); + init_rwsem(&UNIONFS_SB(sb)->rwsem); + + hidden_root_info = unionfs_parse_options(sb, raw_data); + if (IS_ERR(hidden_root_info)) { + printk(KERN_WARNING + "unionfs_read_super: error while parsing options " + "(err = %ld)\n", PTR_ERR(hidden_root_info)); + err = PTR_ERR(hidden_root_info); + hidden_root_info = NULL; + goto out_free; + } + if (hidden_root_info->bstart == -1) { + err = -ENOENT; + goto out_free; + } + + /* set the hidden superblock field of upper superblock */ + bstart = hidden_root_info->bstart; + BUG_ON(bstart != 0); + sbend(sb) = bend = hidden_root_info->bend; + for (bindex = bstart; bindex <= bend; bindex++) { + struct dentry *d; + + d = hidden_root_info->lower_paths[bindex].dentry; + + unionfs_set_lower_super_idx(sb, bindex, d->d_sb); + } + + /* Unionfs: Max Bytes is the maximum bytes from highest priority branch */ + sb->s_maxbytes = unionfs_lower_super_idx(sb, 0)->s_maxbytes; + + sb->s_op = &unionfs_sops; + + /* See comment next to the definition of unionfs_d_alloc_root */ + sb->s_root = unionfs_d_alloc_root(sb); + if (!sb->s_root) { + err = -ENOMEM; + goto out_dput; + } + + /* link the upper and lower dentries */ + sb->s_root->d_fsdata = NULL; + if ((err = new_dentry_private_data(sb->s_root))) + goto out_freedpd; + + /* Set the hidden dentries for s_root */ + for (bindex = bstart; bindex <= bend; bindex++) { + struct dentry *d; + struct vfsmount *m; + + d = hidden_root_info->lower_paths[bindex].dentry; + m = hidden_root_info->lower_paths[bindex].mnt; + + unionfs_set_lower_dentry_idx(sb->s_root, bindex, d); + unionfs_set_lower_mnt_idx(sb->s_root, bindex, m); + } + set_dbstart(sb->s_root, bstart); + set_dbend(sb->s_root, bend); + + /* Set the generation number to one, since this is for the mount. */ + atomic_set(&UNIONFS_D(sb->s_root)->generation, 1); + + /* call interpose to create the upper level inode */ + if ((err = unionfs_interpose(sb->s_root, sb, 0))) + goto out_freedpd; + unionfs_unlock_dentry(sb->s_root); + goto out; + +out_freedpd: + if (UNIONFS_D(sb->s_root)) { + kfree(UNIONFS_D(sb->s_root)->lower_paths); + free_dentry_private_data(UNIONFS_D(sb->s_root)); + } + dput(sb->s_root); + +out_dput: + if (hidden_root_info && !IS_ERR(hidden_root_info)) { + for (bindex = hidden_root_info->bstart; + bindex <= hidden_root_info->bend; bindex++) { + struct dentry *d; + struct vfsmount *m; + + d = hidden_root_info->lower_paths[bindex].dentry; + m = hidden_root_info->lower_paths[bindex].mnt; + + dput(d); + mntput(m); + } + kfree(hidden_root_info->lower_paths); + kfree(hidden_root_info); + hidden_root_info = NULL; + } + +out_free: + kfree(UNIONFS_SB(sb)->data); + kfree(UNIONFS_SB(sb)); + sb->s_fs_info = NULL; + +out: + if (hidden_root_info && !IS_ERR(hidden_root_info)) { + kfree(hidden_root_info->lower_paths); + kfree(hidden_root_info); + } + return err; +} + +static int unionfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *raw_data, struct vfsmount *mnt) +{ + return get_sb_nodev(fs_type, flags, raw_data, unionfs_read_super, mnt); +} + +static struct file_system_type unionfs_fs_type = { + .owner = THIS_MODULE, + .name = "unionfs", + .get_sb = unionfs_get_sb, + .kill_sb = generic_shutdown_super, + .fs_flags = FS_REVAL_DOT, +}; + +static int __init init_unionfs_fs(void) +{ + int err; + printk("Registering unionfs " UNIONFS_VERSION "\n"); + + if ((err = unionfs_init_filldir_cache())) + goto out; + if ((err = unionfs_init_inode_cache())) + goto out; + if ((err = unionfs_init_dentry_cache())) + goto out; + if ((err = init_sioq())) + goto out; + err = register_filesystem(&unionfs_fs_type); +out: + if (err) { + stop_sioq(); + unionfs_destroy_filldir_cache(); + unionfs_destroy_inode_cache(); + unionfs_destroy_dentry_cache(); + } + return err; +} + +static void __exit exit_unionfs_fs(void) +{ + stop_sioq(); + unionfs_destroy_filldir_cache(); + unionfs_destroy_inode_cache(); + unionfs_destroy_dentry_cache(); + unregister_filesystem(&unionfs_fs_type); + printk("Completed unionfs module unload.\n"); +} + +MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University" + " (http://www.fsl.cs.sunysb.edu)"); +MODULE_DESCRIPTION("Unionfs " UNIONFS_VERSION + " (http://unionfs.filesystems.org)"); +MODULE_LICENSE("GPL"); + +module_init(init_unionfs_fs); +module_exit(exit_unionfs_fs); + diff --git a/fs/unionfs/rdstate.c b/fs/unionfs/rdstate.c new file mode 100644 index 0000000..e240285 --- /dev/null +++ b/fs/unionfs/rdstate.c @@ -0,0 +1,281 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* This file contains the routines for maintaining readdir state. */ + +/* There are two structures here, rdstate which is a hash table + * of the second structure which is a filldir_node. + */ + +/* This is a struct kmem_cache for filldir nodes, because we allocate a lot + * of them and they shouldn't waste memory. If the node has a small name + * (as defined by the dentry structure), then we use an inline name to + * preserve kmalloc space. + */ +static struct kmem_cache *unionfs_filldir_cachep; + +int unionfs_init_filldir_cache(void) +{ + unionfs_filldir_cachep = + kmem_cache_create("unionfs_filldir", sizeof(struct filldir_node), 0, + SLAB_RECLAIM_ACCOUNT, NULL, NULL); + + return (unionfs_filldir_cachep ? 0 : -ENOMEM); +} + +void unionfs_destroy_filldir_cache(void) +{ + if (unionfs_filldir_cachep) + kmem_cache_destroy(unionfs_filldir_cachep); +} + +/* This is a tuning parameter that tells us roughly how big to make the + * hash table in directory entries per page. This isn't perfect, but + * at least we get a hash table size that shouldn't be too overloaded. + * The following averages are based on my home directory. + * 14.44693 Overall + * 12.29 Single Page Directories + * 117.93 Multi-page directories + */ +#define DENTPAGE 4096 +#define DENTPERONEPAGE 12 +#define DENTPERPAGE 118 +#define MINHASHSIZE 1 +static int guesstimate_hash_size(struct inode *inode) +{ + struct inode *hidden_inode; + int bindex; + int hashsize = MINHASHSIZE; + + if (UNIONFS_I(inode)->hashsize > 0) + return UNIONFS_I(inode)->hashsize; + + for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) { + if (!(hidden_inode = unionfs_lower_inode_idx(inode, bindex))) + continue; + + if (hidden_inode->i_size == DENTPAGE) + hashsize += DENTPERONEPAGE; + else + hashsize += (hidden_inode->i_size / DENTPAGE) * DENTPERPAGE; + } + + return hashsize; +} + +int init_rdstate(struct file *file) +{ + BUG_ON(sizeof(loff_t) != (sizeof(unsigned int) + sizeof(unsigned int))); + BUG_ON(UNIONFS_F(file)->rdstate != NULL); + + UNIONFS_F(file)->rdstate = alloc_rdstate(file->f_dentry->d_inode, + fbstart(file)); + + return (UNIONFS_F(file)->rdstate ? 0 : -ENOMEM); +} + +struct unionfs_dir_state *find_rdstate(struct inode *inode, loff_t fpos) +{ + struct unionfs_dir_state *rdstate = NULL; + struct list_head *pos; + + spin_lock(&UNIONFS_I(inode)->rdlock); + list_for_each(pos, &UNIONFS_I(inode)->readdircache) { + struct unionfs_dir_state *r = + list_entry(pos, struct unionfs_dir_state, cache); + if (fpos == rdstate2offset(r)) { + UNIONFS_I(inode)->rdcount--; + list_del(&r->cache); + rdstate = r; + break; + } + } + spin_unlock(&UNIONFS_I(inode)->rdlock); + return rdstate; +} + +struct unionfs_dir_state *alloc_rdstate(struct inode *inode, int bindex) +{ + int i = 0; + int hashsize; + unsigned long mallocsize = sizeof(struct unionfs_dir_state); + struct unionfs_dir_state *rdstate; + + hashsize = guesstimate_hash_size(inode); + mallocsize += hashsize * sizeof(struct list_head); + mallocsize = __roundup_pow_of_two(mallocsize); + + /* This should give us about 500 entries anyway. */ + if (mallocsize > PAGE_SIZE) + mallocsize = PAGE_SIZE; + + hashsize = (mallocsize - + sizeof(struct unionfs_dir_state)) / sizeof(struct list_head); + + rdstate = kmalloc(mallocsize, GFP_KERNEL); + if (!rdstate) + return NULL; + + spin_lock(&UNIONFS_I(inode)->rdlock); + if (UNIONFS_I(inode)->cookie >= (MAXRDCOOKIE - 1)) + UNIONFS_I(inode)->cookie = 1; + else + UNIONFS_I(inode)->cookie++; + + rdstate->cookie = UNIONFS_I(inode)->cookie; + spin_unlock(&UNIONFS_I(inode)->rdlock); + rdstate->offset = 1; + rdstate->access = jiffies; + rdstate->bindex = bindex; + rdstate->dirpos = 0; + rdstate->hashentries = 0; + rdstate->size = hashsize; + for (i = 0; i < rdstate->size; i++) + INIT_LIST_HEAD(&rdstate->list[i]); + + return rdstate; +} + +static void free_filldir_node(struct filldir_node *node) +{ + if (node->namelen >= DNAME_INLINE_LEN_MIN) + kfree(node->name); + kmem_cache_free(unionfs_filldir_cachep, node); +} + +void free_rdstate(struct unionfs_dir_state *state) +{ + struct filldir_node *tmp; + int i; + + for (i = 0; i < state->size; i++) { + struct list_head *head = &(state->list[i]); + struct list_head *pos, *n; + + /* traverse the list and deallocate space */ + list_for_each_safe(pos, n, head) { + tmp = list_entry(pos, struct filldir_node, file_list); + list_del(&tmp->file_list); + free_filldir_node(tmp); + } + } + + kfree(state); +} + +struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate, + const char *name, int namelen) +{ + int index; + unsigned int hash; + struct list_head *head; + struct list_head *pos; + struct filldir_node *cursor = NULL; + int found = 0; + + BUG_ON(namelen <= 0); + + hash = full_name_hash(name, namelen); + index = hash % rdstate->size; + + head = &(rdstate->list[index]); + list_for_each(pos, head) { + cursor = list_entry(pos, struct filldir_node, file_list); + + if (cursor->namelen == namelen && cursor->hash == hash && + !strncmp(cursor->name, name, namelen)) { + /* a duplicate exists, and hence no need to create + * entry to the list + */ + found = 1; + + /* if the duplicate is in this branch, then the file + * system is corrupted. + */ + if (cursor->bindex == rdstate->bindex) { + printk(KERN_DEBUG "Possible I/O error " + "unionfs_filldir: a file is duplicated " + "in the same branch %d: %s\n", + rdstate->bindex, cursor->name); + } + break; + } + } + + if (!found) + cursor = NULL; + + return cursor; +} + +static struct filldir_node *alloc_filldir_node(const char *name, int namelen, + unsigned int hash, int bindex) +{ + return kmem_cache_alloc(unionfs_filldir_cachep, GFP_KERNEL); +} + +int add_filldir_node(struct unionfs_dir_state *rdstate, const char *name, + int namelen, int bindex, int whiteout) +{ + struct filldir_node *new; + unsigned int hash; + int index; + int err = 0; + struct list_head *head; + + BUG_ON(namelen <= 0); + + hash = full_name_hash(name, namelen); + index = hash % rdstate->size; + head = &(rdstate->list[index]); + + new = alloc_filldir_node(name, namelen, hash, bindex); + if (!new) { + err = -ENOMEM; + goto out; + } + + INIT_LIST_HEAD(&new->file_list); + new->namelen = namelen; + new->hash = hash; + new->bindex = bindex; + new->whiteout = whiteout; + + if (namelen < DNAME_INLINE_LEN_MIN) + new->name = new->iname; + else { + new->name = kmalloc(namelen + 1, GFP_KERNEL); + if (!new->name) { + kmem_cache_free(unionfs_filldir_cachep, new); + new = NULL; + goto out; + } + } + + memcpy(new->name, name, namelen); + new->name[namelen] = '\0'; + + rdstate->hashentries++; + + list_add(&(new->file_list), head); +out: + return err; +} + diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c new file mode 100644 index 0000000..c9aa040 --- /dev/null +++ b/fs/unionfs/rename.c @@ -0,0 +1,445 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +static int do_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + int bindex, struct dentry **wh_old) +{ + int err = 0; + struct dentry *hidden_old_dentry; + struct dentry *hidden_new_dentry; + struct dentry *hidden_old_dir_dentry; + struct dentry *hidden_new_dir_dentry; + struct dentry *hidden_wh_dentry; + struct dentry *hidden_wh_dir_dentry; + char *wh_name = NULL; + + hidden_new_dentry = unionfs_lower_dentry_idx(new_dentry, bindex); + hidden_old_dentry = unionfs_lower_dentry_idx(old_dentry, bindex); + + if (!hidden_new_dentry) { + hidden_new_dentry = + create_parents(new_dentry->d_parent->d_inode, new_dentry, bindex); + if (IS_ERR(hidden_new_dentry)) { + printk(KERN_DEBUG "error creating directory tree for" + " rename, bindex = %d, err = %ld\n", + bindex, PTR_ERR(hidden_new_dentry)); + err = PTR_ERR(hidden_new_dentry); + goto out; + } + } + + wh_name = alloc_whname(new_dentry->d_name.name, new_dentry->d_name.len); + if (IS_ERR(wh_name)) { + err = PTR_ERR(wh_name); + goto out; + } + + hidden_wh_dentry = lookup_one_len(wh_name, hidden_new_dentry->d_parent, + new_dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(hidden_wh_dentry)) { + err = PTR_ERR(hidden_wh_dentry); + goto out; + } + + if (hidden_wh_dentry->d_inode) { + /* get rid of the whiteout that is existing */ + if (hidden_new_dentry->d_inode) { + printk(KERN_WARNING "Both a whiteout and a dentry" + " exist when doing a rename!\n"); + err = -EIO; + + dput(hidden_wh_dentry); + goto out; + } + + hidden_wh_dir_dentry = lock_parent(hidden_wh_dentry); + if (!(err = is_robranch_super(old_dentry->d_sb, bindex))) + err = vfs_unlink(hidden_wh_dir_dentry->d_inode, + hidden_wh_dentry); + + dput(hidden_wh_dentry); + unlock_dir(hidden_wh_dir_dentry); + if (err) + goto out; + } else + dput(hidden_wh_dentry); + + dget(hidden_old_dentry); + hidden_old_dir_dentry = dget_parent(hidden_old_dentry); + hidden_new_dir_dentry = dget_parent(hidden_new_dentry); + + lock_rename(hidden_old_dir_dentry, hidden_new_dir_dentry); + + err = is_robranch_super(old_dentry->d_sb, bindex); + if (err) + goto out_unlock; + + /* ready to whiteout for old_dentry. caller will create the actual + * whiteout, and must dput(*wh_old) + */ + if (wh_old) { + char *whname; + whname = alloc_whname(old_dentry->d_name.name, + old_dentry->d_name.len); + err = PTR_ERR(whname); + if (IS_ERR(whname)) + goto out_unlock; + *wh_old = lookup_one_len(whname, hidden_old_dir_dentry, + old_dentry->d_name.len + UNIONFS_WHLEN); + kfree(whname); + err = PTR_ERR(*wh_old); + if (IS_ERR(*wh_old)) { + *wh_old = NULL; + goto out_unlock; + } + } + + err = vfs_rename(hidden_old_dir_dentry->d_inode, hidden_old_dentry, + hidden_new_dir_dentry->d_inode, hidden_new_dentry); + +out_unlock: + unlock_rename(hidden_old_dir_dentry, hidden_new_dir_dentry); + + dput(hidden_old_dir_dentry); + dput(hidden_new_dir_dentry); + dput(hidden_old_dentry); + +out: + if (!err) { + /* Fixup the newdentry. */ + if (bindex < dbstart(new_dentry)) + set_dbstart(new_dentry, bindex); + else if (bindex > dbend(new_dentry)) + set_dbend(new_dentry, bindex); + } + + kfree(wh_name); + + return err; +} + +static int do_unionfs_rename(struct inode *old_dir, + struct dentry *old_dentry, + struct inode *new_dir, + struct dentry *new_dentry) +{ + int err = 0; + int bindex, bwh_old; + int old_bstart, old_bend; + int new_bstart, new_bend; + int do_copyup = -1; + struct dentry *parent_dentry; + int local_err = 0; + int eio = 0; + int revert = 0; + struct dentry *wh_old = NULL; + + old_bstart = dbstart(old_dentry); + bwh_old = old_bstart; + old_bend = dbend(old_dentry); + parent_dentry = old_dentry->d_parent; + + new_bstart = dbstart(new_dentry); + new_bend = dbend(new_dentry); + + /* Rename source to destination. */ + err = do_rename(old_dir, old_dentry, new_dir, new_dentry, old_bstart, + &wh_old); + if (err) { + if (!IS_COPYUP_ERR(err)) + goto out; + do_copyup = old_bstart - 1; + } else + revert = 1; + + /* Unlink all instances of destination that exist to the left of + * bstart of source. On error, revert back, goto out. + */ + for (bindex = old_bstart - 1; bindex >= new_bstart; bindex--) { + struct dentry *unlink_dentry; + struct dentry *unlink_dir_dentry; + + unlink_dentry = unionfs_lower_dentry_idx(new_dentry, bindex); + if (!unlink_dentry) + continue; + + unlink_dir_dentry = lock_parent(unlink_dentry); + if (!(err = is_robranch_super(old_dir->i_sb, bindex))) + err = vfs_unlink(unlink_dir_dentry->d_inode, + unlink_dentry); + + fsstack_copy_attr_times(new_dentry->d_parent->d_inode, + unlink_dir_dentry->d_inode); + /* propagate number of hard-links */ + new_dentry->d_parent->d_inode->i_nlink = + unionfs_get_nlinks(new_dentry->d_parent->d_inode); + + unlock_dir(unlink_dir_dentry); + if (!err) { + if (bindex != new_bstart) { + dput(unlink_dentry); + unionfs_set_lower_dentry_idx(new_dentry, bindex, NULL); + } + } else if (IS_COPYUP_ERR(err)) { + do_copyup = bindex - 1; + } else if (revert) { + dput(wh_old); + goto revert; + } + } + + if (do_copyup != -1) { + for (bindex = do_copyup; bindex >= 0; bindex--) { + /* copyup the file into some left directory, so that + * you can rename it + */ + err = copyup_dentry(old_dentry->d_parent->d_inode, + old_dentry, old_bstart, bindex, NULL, + old_dentry->d_inode->i_size); + if (!err) { + dput(wh_old); + bwh_old = bindex; + err = do_rename(old_dir, old_dentry, new_dir, + new_dentry, bindex, &wh_old); + break; + } + } + } + + /* make it opaque */ + if (S_ISDIR(old_dentry->d_inode->i_mode)) { + err = make_dir_opaque(old_dentry, dbstart(old_dentry)); + if (err) + goto revert; + } + + /* Create whiteout for source, only if: + * (1) There is more than one underlying instance of source. + * (2) We did a copy_up + */ + if ((old_bstart != old_bend) || (do_copyup != -1)) { + struct dentry *hidden_parent; + BUG_ON(!wh_old || wh_old->d_inode || bwh_old < 0); + hidden_parent = lock_parent(wh_old); + local_err = vfs_create(hidden_parent->d_inode, wh_old, S_IRUGO, + NULL); + unlock_dir(hidden_parent); + if (!local_err) + set_dbopaque(old_dentry, bwh_old); + else { + /* We can't fix anything now, so we cop-out and use -EIO. */ + printk(KERN_ERR "We can't create a whiteout for the " + "source in rename!\n"); + err = -EIO; + } + } + +out: + dput(wh_old); + return err; + +revert: + /* Do revert here. */ + local_err = unionfs_refresh_hidden_dentry(new_dentry, old_bstart); + if (local_err) { + printk(KERN_WARNING "Revert failed in rename: the new refresh " + "failed.\n"); + eio = -EIO; + } + + local_err = unionfs_refresh_hidden_dentry(old_dentry, old_bstart); + if (local_err) { + printk(KERN_WARNING "Revert failed in rename: the old refresh " + "failed.\n"); + eio = -EIO; + goto revert_out; + } + + if (!unionfs_lower_dentry_idx(new_dentry, bindex) || + !unionfs_lower_dentry_idx(new_dentry, bindex)->d_inode) { + printk(KERN_WARNING "Revert failed in rename: the object " + "disappeared from under us!\n"); + eio = -EIO; + goto revert_out; + } + + if (unionfs_lower_dentry_idx(old_dentry, bindex) && + unionfs_lower_dentry_idx(old_dentry, bindex)->d_inode) { + printk(KERN_WARNING "Revert failed in rename: the object was " + "created underneath us!\n"); + eio = -EIO; + goto revert_out; + } + + local_err = do_rename(new_dir, new_dentry, old_dir, old_dentry, old_bstart, + NULL); + + /* If we can't fix it, then we cop-out with -EIO. */ + if (local_err) { + printk(KERN_WARNING "Revert failed in rename!\n"); + eio = -EIO; + } + + local_err = unionfs_refresh_hidden_dentry(new_dentry, bindex); + if (local_err) + eio = -EIO; + local_err = unionfs_refresh_hidden_dentry(old_dentry, bindex); + if (local_err) + eio = -EIO; + +revert_out: + if (eio) + err = eio; + return err; +} + +static struct dentry *lookup_whiteout(struct dentry *dentry) +{ + char *whname; + int bindex = -1, bstart = -1, bend = -1; + struct dentry *parent, *hidden_parent, *wh_dentry; + + whname = alloc_whname(dentry->d_name.name, dentry->d_name.len); + if (IS_ERR(whname)) + return (void *)whname; + + parent = dget_parent(dentry); + unionfs_lock_dentry(parent); + bstart = dbstart(parent); + bend = dbend(parent); + wh_dentry = ERR_PTR(-ENOENT); + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_parent = unionfs_lower_dentry_idx(parent, bindex); + if (!hidden_parent) + continue; + wh_dentry = lookup_one_len(whname, hidden_parent, + dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(wh_dentry)) + continue; + if (wh_dentry->d_inode) + break; + dput(wh_dentry); + wh_dentry = ERR_PTR(-ENOENT); + } + unionfs_unlock_dentry(parent); + dput(parent); + kfree(whname); + return wh_dentry; +} + +/* We can't copyup a directory, because it may involve huge + * numbers of children, etc. Doing that in the kernel would + * be bad, so instead we let the userspace recurse and ask us + * to copy up each file separately + */ +static int may_rename_dir(struct dentry *dentry) +{ + int err, bstart; + + err = check_empty(dentry, NULL); + if (err == -ENOTEMPTY) { + if (is_robranch(dentry)) + return -EXDEV; + } else if (err) + return err; + + bstart = dbstart(dentry); + if (dbend(dentry) == bstart || dbopaque(dentry) == bstart) + return 0; + + set_dbstart(dentry, bstart + 1); + err = check_empty(dentry, NULL); + set_dbstart(dentry, bstart); + if (err == -ENOTEMPTY) + err = -EXDEV; + return err; +} + +int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + int err = 0; + struct dentry *wh_dentry; + + double_lock_dentry(old_dentry, new_dentry); + + if (!S_ISDIR(old_dentry->d_inode->i_mode)) + err = unionfs_partial_lookup(old_dentry); + else + err = may_rename_dir(old_dentry); + + if (err) + goto out; + + err = unionfs_partial_lookup(new_dentry); + if (err) + goto out; + + /* + * if new_dentry is already hidden because of whiteout, + * simply override it even if the whiteouted dir is not empty. + */ + wh_dentry = lookup_whiteout(new_dentry); + if (!IS_ERR(wh_dentry)) + dput(wh_dentry); + else if (new_dentry->d_inode) { + if (S_ISDIR(old_dentry->d_inode->i_mode) != + S_ISDIR(new_dentry->d_inode->i_mode)) { + err = S_ISDIR(old_dentry->d_inode->i_mode) ? + -ENOTDIR : -EISDIR; + goto out; + } + + if (S_ISDIR(new_dentry->d_inode->i_mode)) { + struct unionfs_dir_state *namelist; + /* check if this unionfs directory is empty or not */ + err = check_empty(new_dentry, &namelist); + if (err) + goto out; + + if (!is_robranch(new_dentry)) + err = delete_whiteouts(new_dentry, + dbstart(new_dentry), + namelist); + + free_rdstate(namelist); + + if (err) + goto out; + } + } + err = do_unionfs_rename(old_dir, old_dentry, new_dir, new_dentry); + +out: + if (err) + /* clear the new_dentry stuff created */ + d_drop(new_dentry); + else + /* force re-lookup since the dir on ro branch is not renamed, + and hidden dentries still indicate the un-renamed ones. */ + if (S_ISDIR(old_dentry->d_inode->i_mode)) + atomic_dec(&UNIONFS_D(old_dentry)->generation); + + unionfs_unlock_dentry(new_dentry); + unionfs_unlock_dentry(old_dentry); + return err; +} + diff --git a/fs/unionfs/sioq.c b/fs/unionfs/sioq.c new file mode 100644 index 0000000..7830b89 --- /dev/null +++ b/fs/unionfs/sioq.c @@ -0,0 +1,123 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* Super-user IO work Queue - sometimes we need to perform actions which + * would fail due to the unix permissions on the parent directory (e.g., + * rmdir a directory which appears empty, but in reality contains + * whiteouts). + */ + +static struct workqueue_struct *superio_workqueue; + +int __init init_sioq(void) +{ + int err; + + superio_workqueue = create_workqueue("unionfs_siod"); + if (!IS_ERR(superio_workqueue)) + return 0; + + err = PTR_ERR(superio_workqueue); + printk(KERN_ERR "create_workqueue failed %d\n", err); + superio_workqueue = NULL; + return err; +} + +void __exit stop_sioq(void) +{ + if (superio_workqueue) + destroy_workqueue(superio_workqueue); +} + +void run_sioq(work_func_t func, struct sioq_args *args) +{ + INIT_WORK(&args->work, func); + + init_completion(&args->comp); + while (!queue_work(superio_workqueue, &args->work)) { + /* TODO: do accounting if needed */ + schedule(); + } + wait_for_completion(&args->comp); +} + +void __unionfs_create(struct work_struct *work) +{ + struct sioq_args *args = container_of(work, struct sioq_args, work); + struct create_args *c = &args->create; + + args->err = vfs_create(c->parent, c->dentry, c->mode, c->nd); + complete(&args->comp); +} + +void __unionfs_mkdir(struct work_struct *work) +{ + struct sioq_args *args = container_of(work, struct sioq_args, work); + struct mkdir_args *m = &args->mkdir; + + args->err = vfs_mkdir(m->parent, m->dentry, m->mode); + complete(&args->comp); +} + +void __unionfs_mknod(struct work_struct *work) +{ + struct sioq_args *args = container_of(work, struct sioq_args, work); + struct mknod_args *m = &args->mknod; + + args->err = vfs_mknod(m->parent, m->dentry, m->mode, m->dev); + complete(&args->comp); +} + +void __unionfs_symlink(struct work_struct *work) +{ + struct sioq_args *args = container_of(work, struct sioq_args, work); + struct symlink_args *s = &args->symlink; + + args->err = vfs_symlink(s->parent, s->dentry, s->symbuf, s->mode); + complete(&args->comp); +} + +void __unionfs_unlink(struct work_struct *work) +{ + struct sioq_args *args = container_of(work, struct sioq_args, work); + struct unlink_args *u = &args->unlink; + + args->err = vfs_unlink(u->parent, u->dentry); + complete(&args->comp); +} + +void __delete_whiteouts(struct work_struct *work) +{ + struct sioq_args *args = container_of(work, struct sioq_args, work); + struct deletewh_args *d = &args->deletewh; + + args->err = do_delete_whiteouts(d->dentry, d->bindex, d->namelist); + complete(&args->comp); +} + +void __is_opaque_dir(struct work_struct *work) +{ + struct sioq_args *args = container_of(work, struct sioq_args, work); + + args->ret = lookup_one_len(UNIONFS_DIR_OPAQUE, args->is_opaque.dentry, + sizeof(UNIONFS_DIR_OPAQUE) - 1); + complete(&args->comp); +} + diff --git a/fs/unionfs/sioq.h b/fs/unionfs/sioq.h new file mode 100644 index 0000000..20e3b0c --- /dev/null +++ b/fs/unionfs/sioq.h @@ -0,0 +1,78 @@ +#ifndef _SIOQ_H +#define _SIOQ_H + +struct deletewh_args { + struct unionfs_dir_state *namelist; + struct dentry *dentry; + int bindex; +}; + +struct is_opaque_args { + struct dentry *dentry; +}; + +struct create_args { + struct inode *parent; + struct dentry *dentry; + umode_t mode; + struct nameidata *nd; +}; + +struct mkdir_args { + struct inode *parent; + struct dentry *dentry; + umode_t mode; +}; + +struct mknod_args { + struct inode *parent; + struct dentry *dentry; + umode_t mode; + dev_t dev; +}; + +struct symlink_args { + struct inode *parent; + struct dentry *dentry; + char *symbuf; + umode_t mode; +}; + +struct unlink_args { + struct inode *parent; + struct dentry *dentry; +}; + + +struct sioq_args { + struct completion comp; + struct work_struct work; + int err; + void *ret; + + union { + struct deletewh_args deletewh; + struct is_opaque_args is_opaque; + struct create_args create; + struct mkdir_args mkdir; + struct mknod_args mknod; + struct symlink_args symlink; + struct unlink_args unlink; + }; +}; + +extern int __init init_sioq(void); +extern __exit void stop_sioq(void); +extern void run_sioq(work_func_t func, struct sioq_args *args); + +/* Extern definitions for our privlege escalation helpers */ +extern void __unionfs_create(struct work_struct *work); +extern void __unionfs_mkdir(struct work_struct *work); +extern void __unionfs_mknod(struct work_struct *work); +extern void __unionfs_symlink(struct work_struct *work); +extern void __unionfs_unlink(struct work_struct *work); +extern void __delete_whiteouts(struct work_struct *work); +extern void __is_opaque_dir(struct work_struct *work); + +#endif /* _SIOQ_H */ + diff --git a/fs/unionfs/subr.c b/fs/unionfs/subr.c new file mode 100644 index 0000000..d274752 --- /dev/null +++ b/fs/unionfs/subr.c @@ -0,0 +1,233 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* Pass an unionfs dentry and an index. It will try to create a whiteout + * for the filename in dentry, and will try in branch 'index'. On error, + * it will proceed to a branch to the left. + */ +int create_whiteout(struct dentry *dentry, int start) +{ + int bstart, bend, bindex; + struct dentry *hidden_dir_dentry; + struct dentry *hidden_dentry; + struct dentry *hidden_wh_dentry; + char *name = NULL; + int err = -EINVAL; + + verify_locked(dentry); + + bstart = dbstart(dentry); + bend = dbend(dentry); + + /* create dentry's whiteout equivalent */ + name = alloc_whname(dentry->d_name.name, dentry->d_name.len); + if (IS_ERR(name)) { + err = PTR_ERR(name); + goto out; + } + + for (bindex = start; bindex >= 0; bindex--) { + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + + if (!hidden_dentry) { + /* if hidden dentry is not present, create the entire + * hidden dentry directory structure and go ahead. + * Since we want to just create whiteout, we only want + * the parent dentry, and hence get rid of this dentry. + */ + hidden_dentry = create_parents(dentry->d_inode, + dentry, bindex); + if (!hidden_dentry || IS_ERR(hidden_dentry)) { + printk(KERN_DEBUG "create_parents failed for " + "bindex = %d\n", bindex); + continue; + } + } + + hidden_wh_dentry = lookup_one_len(name, hidden_dentry->d_parent, + dentry->d_name.len + UNIONFS_WHLEN); + if (IS_ERR(hidden_wh_dentry)) + continue; + + /* The whiteout already exists. This used to be impossible, but + * now is possible because of opaqueness. + */ + if (hidden_wh_dentry->d_inode) { + dput(hidden_wh_dentry); + err = 0; + goto out; + } + + hidden_dir_dentry = lock_parent(hidden_wh_dentry); + if (!(err = is_robranch_super(dentry->d_sb, bindex))) { + err = vfs_create(hidden_dir_dentry->d_inode, + hidden_wh_dentry, + ~current->fs->umask & S_IRWXUGO, NULL); + + } + unlock_dir(hidden_dir_dentry); + dput(hidden_wh_dentry); + + if (!err || !IS_COPYUP_ERR(err)) + break; + } + + /* set dbopaque so that lookup will not proceed after this branch */ + if (!err) + set_dbopaque(dentry, bindex); + +out: + kfree(name); + return err; +} + +/* This is a helper function for rename, which ends up with hosed over dentries + * when it needs to revert. + */ +int unionfs_refresh_hidden_dentry(struct dentry *dentry, int bindex) +{ + struct dentry *hidden_dentry; + struct dentry *hidden_parent; + int err = 0; + + verify_locked(dentry); + + unionfs_lock_dentry(dentry->d_parent); + hidden_parent = unionfs_lower_dentry_idx(dentry->d_parent, bindex); + unionfs_unlock_dentry(dentry->d_parent); + + BUG_ON(!S_ISDIR(hidden_parent->d_inode->i_mode)); + + hidden_dentry = lookup_one_len(dentry->d_name.name, hidden_parent, + dentry->d_name.len); + if (IS_ERR(hidden_dentry)) { + err = PTR_ERR(hidden_dentry); + goto out; + } + + dput(unionfs_lower_dentry_idx(dentry, bindex)); + iput(unionfs_lower_inode_idx(dentry->d_inode, bindex)); + unionfs_set_lower_inode_idx(dentry->d_inode, bindex, NULL); + + if (!hidden_dentry->d_inode) { + dput(hidden_dentry); + unionfs_set_lower_dentry_idx(dentry, bindex, NULL); + } else { + unionfs_set_lower_dentry_idx(dentry, bindex, hidden_dentry); + unionfs_set_lower_inode_idx(dentry->d_inode, bindex, + igrab(hidden_dentry->d_inode)); + } + +out: + return err; +} + +int make_dir_opaque(struct dentry *dentry, int bindex) +{ + int err = 0; + struct dentry *hidden_dentry, *diropq; + struct inode *hidden_dir; + + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + hidden_dir = hidden_dentry->d_inode; + BUG_ON(!S_ISDIR(dentry->d_inode->i_mode) || + !S_ISDIR(hidden_dir->i_mode)); + + mutex_lock(&hidden_dir->i_mutex); + diropq = lookup_one_len(UNIONFS_DIR_OPAQUE, hidden_dentry, + sizeof(UNIONFS_DIR_OPAQUE) - 1); + if (IS_ERR(diropq)) { + err = PTR_ERR(diropq); + goto out; + } + + if (!diropq->d_inode) + err = vfs_create(hidden_dir, diropq, S_IRUGO, NULL); + if (!err) + set_dbopaque(dentry, bindex); + + dput(diropq); + +out: + mutex_unlock(&hidden_dir->i_mutex); + return err; +} + +/* returns the sum of the n_link values of all the underlying inodes of the + * passed inode + */ +int unionfs_get_nlinks(struct inode *inode) +{ + int sum_nlinks = 0; + int dirs = 0; + int bindex; + struct inode *hidden_inode; + + /* don't bother to do all the work since we're unlinked */ + if (inode->i_nlink == 0) + return 0; + + if (!S_ISDIR(inode->i_mode)) + return unionfs_lower_inode(inode)->i_nlink; + + for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) { + hidden_inode = unionfs_lower_inode_idx(inode, bindex); + + /* ignore files */ + if (!hidden_inode || !S_ISDIR(hidden_inode->i_mode)) + continue; + + BUG_ON(hidden_inode->i_nlink < 0); + + /* A deleted directory. */ + if (hidden_inode->i_nlink == 0) + continue; + dirs++; + + /* + * A broken directory... + * + * Some filesystems don't properly set the number of links + * on empty directories + */ + if (hidden_inode->i_nlink == 1) + sum_nlinks += 2; + else + sum_nlinks += (hidden_inode->i_nlink - 2); + } + + return (!dirs ? 0 : sum_nlinks + 2); +} + +/* construct whiteout filename */ +char *alloc_whname(const char *name, int len) +{ + char *buf; + + buf = kmalloc(len + UNIONFS_WHLEN + 1, GFP_KERNEL); + if (!buf) + return ERR_PTR(-ENOMEM); + + strcpy(buf, UNIONFS_WHPFX); + strlcat(buf, name, len + UNIONFS_WHLEN + 1); + + return buf; +} + diff --git a/fs/unionfs/super.c b/fs/unionfs/super.c new file mode 100644 index 0000000..38443c7 --- /dev/null +++ b/fs/unionfs/super.c @@ -0,0 +1,345 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* The inode cache is used with alloc_inode for both our inode info and the + * vfs inode. + */ +static struct kmem_cache *unionfs_inode_cachep; + +static void unionfs_read_inode(struct inode *inode) +{ + static struct address_space_operations unionfs_empty_aops; + int size; + struct unionfs_inode_info *info = UNIONFS_I(inode); + + if (!info) { + printk(KERN_ERR "No kernel memory when allocating inode " + "private data!\n"); + BUG(); + } + + memset(info, 0, offsetof(struct unionfs_inode_info, vfs_inode)); + info->bstart = -1; + info->bend = -1; + atomic_set(&info->generation, + atomic_read(&UNIONFS_SB(inode->i_sb)->generation)); + spin_lock_init(&info->rdlock); + info->rdcount = 1; + info->hashsize = -1; + INIT_LIST_HEAD(&info->readdircache); + + size = sbmax(inode->i_sb) * sizeof(struct inode *); + info->lower_inodes = kzalloc(size, GFP_KERNEL); + if (!info->lower_inodes) { + printk(KERN_ERR "No kernel memory when allocating lower-" + "pointer array!\n"); + BUG(); + } + + inode->i_version++; + inode->i_op = &unionfs_main_iops; + inode->i_fop = &unionfs_main_fops; + + /* I don't think ->a_ops is ever allowed to be NULL */ + inode->i_mapping->a_ops = &unionfs_empty_aops; +} + +static void unionfs_put_inode(struct inode *inode) +{ + /* + * This is really funky stuff: + * Basically, if i_count == 1, iput will then decrement it and this + * inode will be destroyed. It is currently holding a reference to the + * hidden inode. Therefore, it needs to release that reference by + * calling iput on the hidden inode. iput() _will_ do it for us (by + * calling our clear_inode), but _only_ if i_nlink == 0. The problem + * is, NFS keeps i_nlink == 1 for silly_rename'd files. So we must for + * our i_nlink to 0 here to trick iput() into calling our clear_inode. + */ + + if (atomic_read(&inode->i_count) == 1) + inode->i_nlink = 0; +} + +/* + * we now define delete_inode, because there are two VFS paths that may + * destroy an inode: one of them calls clear inode before doing everything + * else that's needed, and the other is fine. This way we truncate the inode + * size (and its pages) and then clear our own inode, which will do an iput + * on our and the lower inode. + */ +static void unionfs_delete_inode(struct inode *inode) +{ + inode->i_size = 0; /* every f/s seems to do that */ + + clear_inode(inode); +} + +/* final actions when unmounting a file system */ +static void unionfs_put_super(struct super_block *sb) +{ + int bindex, bstart, bend; + struct unionfs_sb_info *spd; + + spd = UNIONFS_SB(sb); + if (!spd) + return; + + bstart = sbstart(sb); + bend = sbend(sb); + + /* Make sure we have no leaks of branchget/branchput. */ + for (bindex = bstart; bindex <= bend; bindex++) + BUG_ON(branch_count(sb, bindex) != 0); + + kfree(spd->data); + kfree(spd); + sb->s_fs_info = NULL; +} + +/* Since people use this to answer the "How big of a file can I write?" + * question, we report the size of the highest priority branch as the size of + * the union. + */ +static int unionfs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + int err = 0; + struct super_block *sb, *hidden_sb; + + sb = dentry->d_sb; + + hidden_sb = unionfs_lower_super_idx(sb, sbstart(sb)); + err = vfs_statfs(hidden_sb->s_root, buf); + + buf->f_type = UNIONFS_SUPER_MAGIC; + buf->f_namelen -= UNIONFS_WHLEN; + + memset(&buf->f_fsid, 0, sizeof(__kernel_fsid_t)); + memset(&buf->f_spare, 0, sizeof(buf->f_spare)); + + return err; +} + +/* We don't support a standard text remount. Eventually it would be nice to + * support a full-on remount, so that you can have all of the directories + * change at once, but that would require some pretty complicated matching + * code. + */ +static int unionfs_remount_fs(struct super_block *sb, int *flags, char *data) +{ + return -ENOSYS; +} + +/* + * Called by iput() when the inode reference count reached zero + * and the inode is not hashed anywhere. Used to clear anything + * that needs to be, before the inode is completely destroyed and put + * on the inode free list. + */ +static void unionfs_clear_inode(struct inode *inode) +{ + int bindex, bstart, bend; + struct inode *hidden_inode; + struct list_head *pos, *n; + struct unionfs_dir_state *rdstate; + + list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) { + rdstate = list_entry(pos, struct unionfs_dir_state, cache); + list_del(&rdstate->cache); + free_rdstate(rdstate); + } + + /* Decrement a reference to a hidden_inode, which was incremented + * by our read_inode when it was created initially. + */ + bstart = ibstart(inode); + bend = ibend(inode); + if (bstart >= 0) { + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_inode = unionfs_lower_inode_idx(inode, bindex); + if (!hidden_inode) + continue; + iput(hidden_inode); + } + } + + kfree(UNIONFS_I(inode)->lower_inodes); + UNIONFS_I(inode)->lower_inodes = NULL; +} + +static struct inode *unionfs_alloc_inode(struct super_block *sb) +{ + struct unionfs_inode_info *i; + + i = kmem_cache_alloc(unionfs_inode_cachep, GFP_KERNEL); + if (!i) + return NULL; + + /* memset everything up to the inode to 0 */ + memset(i, 0, offsetof(struct unionfs_inode_info, vfs_inode)); + + i->vfs_inode.i_version = 1; + return &i->vfs_inode; +} + +static void unionfs_destroy_inode(struct inode *inode) +{ + kmem_cache_free(unionfs_inode_cachep, UNIONFS_I(inode)); +} + +/* unionfs inode cache constructor */ +static void init_once(void *v, struct kmem_cache * cachep, unsigned long flags) +{ + struct unionfs_inode_info *i = v; + + if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == + SLAB_CTOR_CONSTRUCTOR) + inode_init_once(&i->vfs_inode); +} + +int unionfs_init_inode_cache(void) +{ + int err = 0; + + unionfs_inode_cachep = + kmem_cache_create("unionfs_inode_cache", + sizeof(struct unionfs_inode_info), 0, + SLAB_RECLAIM_ACCOUNT, init_once, NULL); + if (!unionfs_inode_cachep) + err = -ENOMEM; + return err; +} + +void unionfs_destroy_inode_cache(void) +{ + if (unionfs_inode_cachep) + kmem_cache_destroy(unionfs_inode_cachep); +} + +/* Called when we have a dirty inode, right here we only throw out + * parts of our readdir list that are too old. + */ +static int unionfs_write_inode(struct inode *inode, int sync) +{ + struct list_head *pos, *n; + struct unionfs_dir_state *rdstate; + + spin_lock(&UNIONFS_I(inode)->rdlock); + list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) { + rdstate = list_entry(pos, struct unionfs_dir_state, cache); + /* We keep this list in LRU order. */ + if ((rdstate->access + RDCACHE_JIFFIES) > jiffies) + break; + UNIONFS_I(inode)->rdcount--; + list_del(&rdstate->cache); + free_rdstate(rdstate); + } + spin_unlock(&UNIONFS_I(inode)->rdlock); + + return 0; +} + +/* + * Used only in nfs, to kill any pending RPC tasks, so that subsequent + * code can actually succeed and won't leave tasks that need handling. + */ +static void unionfs_umount_begin(struct vfsmount *mnt, int flags) +{ + struct super_block *sb, *hidden_sb; + struct vfsmount *hidden_mnt; + int bindex, bstart, bend; + + if (!(flags & MNT_FORCE)) + /* we are not being MNT_FORCEd, therefore we should emulate + * old behaviour + */ + return; + + sb = mnt->mnt_sb; + + bstart = sbstart(sb); + bend = sbend(sb); + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_mnt = unionfs_lower_mnt_idx(sb->s_root, bindex); + hidden_sb = unionfs_lower_super_idx(sb, bindex); + + if (hidden_mnt && hidden_sb && hidden_sb->s_op && + hidden_sb->s_op->umount_begin) + hidden_sb->s_op->umount_begin(hidden_mnt, flags); + } +} + +static int unionfs_show_options(struct seq_file *m, struct vfsmount *mnt) +{ + struct super_block *sb = mnt->mnt_sb; + int ret = 0; + char *tmp_page; + char *path; + int bindex, bstart, bend; + int perms; + + unionfs_lock_dentry(sb->s_root); + + tmp_page = (char*) __get_free_page(GFP_KERNEL); + if (!tmp_page) { + ret = -ENOMEM; + goto out; + } + + bstart = sbstart(sb); + bend = sbend(sb); + + seq_printf(m, ",dirs="); + for (bindex = bstart; bindex <= bend; bindex++) { + path = d_path(unionfs_lower_dentry_idx(sb->s_root, bindex), + unionfs_lower_mnt_idx(sb->s_root, bindex), tmp_page, + PAGE_SIZE); + perms = branchperms(sb, bindex); + + seq_printf(m, "%s=%s", path, + perms & MAY_WRITE ? "rw" : "ro"); + if (bindex != bend) { + seq_printf(m, ":"); + } + } + +out: + free_page((unsigned long) tmp_page); + + unionfs_unlock_dentry(sb->s_root); + + return ret; +} + +struct super_operations unionfs_sops = { + .read_inode = unionfs_read_inode, + .put_inode = unionfs_put_inode, + .delete_inode = unionfs_delete_inode, + .put_super = unionfs_put_super, + .statfs = unionfs_statfs, + .remount_fs = unionfs_remount_fs, + .clear_inode = unionfs_clear_inode, + .umount_begin = unionfs_umount_begin, + .show_options = unionfs_show_options, + .write_inode = unionfs_write_inode, + .alloc_inode = unionfs_alloc_inode, + .destroy_inode = unionfs_destroy_inode, +}; + diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h new file mode 100644 index 0000000..fc87b03 --- /dev/null +++ b/fs/unionfs/union.h @@ -0,0 +1,439 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _UNION_H_ +#define _UNION_H_ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include + +/* the file system name */ +#define UNIONFS_NAME "unionfs" + +/* unionfs root inode number */ +#define UNIONFS_ROOT_INO 1 + +/* Mount time flags */ +#define MOUNT_FLAG(sb) (UNIONFS_SB(sb)->mount_flag) + +/* number of characters while generating unique temporary file names */ +#define UNIONFS_TMPNAM_LEN 12 + +/* number of times we try to get a unique temporary file name */ +#define GET_TMPNAM_MAX_RETRY 5 + +/* Operations vectors defined in specific files. */ +extern struct file_operations unionfs_main_fops; +extern struct file_operations unionfs_dir_fops; +extern struct inode_operations unionfs_main_iops; +extern struct inode_operations unionfs_dir_iops; +extern struct inode_operations unionfs_symlink_iops; +extern struct super_operations unionfs_sops; +extern struct dentry_operations unionfs_dops; + +/* How long should an entry be allowed to persist */ +#define RDCACHE_JIFFIES (5*HZ) + +/* file private data. */ +struct unionfs_file_info { + int bstart; + int bend; + atomic_t generation; + + struct unionfs_dir_state *rdstate; + struct file **lower_files; +}; + +/* unionfs inode data in memory */ +struct unionfs_inode_info { + int bstart; + int bend; + atomic_t generation; + int stale; + /* Stuff for readdir over NFS. */ + spinlock_t rdlock; + struct list_head readdircache; + int rdcount; + int hashsize; + int cookie; + + /* The hidden inodes */ + struct inode **lower_inodes; + /* to keep track of reads/writes for unlinks before closes */ + atomic_t totalopens; + + struct inode vfs_inode; +}; + +/* unionfs dentry data in memory */ +struct unionfs_dentry_info { + /* The semaphore is used to lock the dentry as soon as we get into a + * unionfs function from the VFS. Our lock ordering is that children + * go before their parents. + */ + struct mutex lock; + int bstart; + int bend; + int bopaque; + int bcount; + atomic_t generation; + struct path *lower_paths; +}; + +/* These are the pointers to our various objects. */ +struct unionfs_data { + struct super_block *sb; + struct vfsmount *hidden_mnt; + atomic_t sbcount; + int branchperms; +}; + +/* unionfs super-block data in memory */ +struct unionfs_sb_info { + int bend; + + atomic_t generation; + unsigned long mount_flag; + struct rw_semaphore rwsem; + + struct unionfs_data *data; +}; + +/* + * structure for making the linked list of entries by readdir on left branch + * to compare with entries on right branch + */ +struct filldir_node { + struct list_head file_list; /* list for directory entries */ + char *name; /* name entry */ + int hash; /* name hash */ + int namelen; /* name len since name is not 0 terminated */ + + /* we can check for duplicate whiteouts and files in the same branch + * in order to return -EIO. + */ + int bindex; + + /* is this a whiteout entry? */ + int whiteout; + + /* Inline name, so we don't need to separately kmalloc small ones */ + char iname[DNAME_INLINE_LEN_MIN]; +}; + +/* Directory hash table. */ +struct unionfs_dir_state { + unsigned int cookie; /* The cookie, which is based off of rdversion */ + unsigned int offset; /* The entry we have returned. */ + int bindex; + loff_t dirpos; /* The offset within the lower level directory. */ + int size; /* How big is the hash table? */ + int hashentries; /* How many entries have been inserted? */ + unsigned long access; + + /* This cache list is used when the inode keeps us around. */ + struct list_head cache; + struct list_head list[0]; +}; + +/* include miscellaneous macros */ +#include "fanout.h" +#include "sioq.h" + +/* Cache creation/deletion routines. */ +void unionfs_destroy_filldir_cache(void); +int unionfs_init_filldir_cache(void); +int unionfs_init_inode_cache(void); +void unionfs_destroy_inode_cache(void); +int unionfs_init_dentry_cache(void); +void unionfs_destroy_dentry_cache(void); + +/* Initialize and free readdir-specific state. */ +int init_rdstate(struct file *file); +struct unionfs_dir_state *alloc_rdstate(struct inode *inode, int bindex); +struct unionfs_dir_state *find_rdstate(struct inode *inode, loff_t fpos); +void free_rdstate(struct unionfs_dir_state *state); +int add_filldir_node(struct unionfs_dir_state *rdstate, const char *name, + int namelen, int bindex, int whiteout); +struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate, + const char *name, int namelen); + +struct dentry **alloc_new_dentries(int objs); +struct unionfs_data *alloc_new_data(int objs); + +/* We can only use 32-bits of offset for rdstate --- blech! */ +#define DIREOF (0xfffff) +#define RDOFFBITS 20 /* This is the number of bits in DIREOF. */ +#define MAXRDCOOKIE (0xfff) +/* Turn an rdstate into an offset. */ +static inline off_t rdstate2offset(struct unionfs_dir_state *buf) +{ + off_t tmp; + tmp = ((buf->cookie & MAXRDCOOKIE) << RDOFFBITS) + | (buf->offset & DIREOF); + return tmp; +} + +#define unionfs_read_lock(sb) down_read(&UNIONFS_SB(sb)->rwsem) +#define unionfs_read_unlock(sb) up_read(&UNIONFS_SB(sb)->rwsem) +#define unionfs_write_lock(sb) down_write(&UNIONFS_SB(sb)->rwsem) +#define unionfs_write_unlock(sb) up_write(&UNIONFS_SB(sb)->rwsem) + +static inline void double_lock_dentry(struct dentry *d1, struct dentry *d2) +{ + if (d2 < d1) { + struct dentry *tmp = d1; + d1 = d2; + d2 = tmp; + } + unionfs_lock_dentry(d1); + unionfs_lock_dentry(d2); +} + +extern int new_dentry_private_data(struct dentry *dentry); +void free_dentry_private_data(struct unionfs_dentry_info *udi); +void update_bstart(struct dentry *dentry); + +/* + * EXTERNALS: + */ + +/* replicates the directory structure upto given dentry in given branch */ +extern struct dentry *create_parents(struct inode *dir, struct dentry *dentry, + int bindex); + +/* partial lookup */ +extern int unionfs_partial_lookup(struct dentry *dentry); + +/* Pass an unionfs dentry and an index and it will try to create a whiteout + * in branch 'index'. + * + * On error, it will proceed to a branch to the left + */ +extern int create_whiteout(struct dentry *dentry, int start); +/* copies a file from dbstart to newbindex branch */ +extern int copyup_file(struct inode *dir, struct file *file, int bstart, + int newbindex, loff_t size); +extern int copyup_named_file(struct inode *dir, struct file *file, + char *name, int bstart, int new_bindex, + loff_t len); +/* copies a dentry from dbstart to newbindex branch */ +extern int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart, + int new_bindex, struct file **copyup_file, loff_t len); + +extern int remove_whiteouts(struct dentry *dentry, struct dentry *hidden_dentry, + int bindex); + +extern int do_delete_whiteouts(struct dentry *dentry, int bindex, + struct unionfs_dir_state *namelist); + +extern int unionfs_get_nlinks(struct inode *inode); + +/* Is this directory empty: 0 if it is empty, -ENOTEMPTY if not. */ +extern int check_empty(struct dentry *dentry, + struct unionfs_dir_state **namelist); +/* Delete whiteouts from this directory in branch bindex. */ +extern int delete_whiteouts(struct dentry *dentry, int bindex, + struct unionfs_dir_state *namelist); + +/* Re-lookup a hidden dentry. */ +extern int unionfs_refresh_hidden_dentry(struct dentry *dentry, int bindex); + +extern void unionfs_reinterpose(struct dentry *this_dentry); +extern struct super_block *unionfs_duplicate_super(struct super_block *sb); + +/* Locking functions. */ +extern int unionfs_setlk(struct file *file, int cmd, struct file_lock *fl); +extern int unionfs_getlk(struct file *file, struct file_lock *fl); + +/* Common file operations. */ +extern int unionfs_file_revalidate(struct file *file, int willwrite); +extern int unionfs_open(struct inode *inode, struct file *file); +extern int unionfs_file_release(struct inode *inode, struct file *file); +extern int unionfs_flush(struct file *file, fl_owner_t id); +extern long unionfs_ioctl(struct file *file, unsigned int cmd, + unsigned long arg); + +/* Inode operations */ +extern int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry); +int unionfs_unlink(struct inode *dir, struct dentry *dentry); +int unionfs_rmdir(struct inode *dir, struct dentry *dentry); + +int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd); + +/* The values for unionfs_interpose's flag. */ +#define INTERPOSE_DEFAULT 0 +#define INTERPOSE_LOOKUP 1 +#define INTERPOSE_REVAL 2 +#define INTERPOSE_REVAL_NEG 3 +#define INTERPOSE_PARTIAL 4 + +extern int unionfs_interpose(struct dentry *this_dentry, struct super_block *sb, + int flag); + +/* Branch management ioctls. */ +int unionfs_ioctl_incgen(struct file *file, unsigned int cmd, + unsigned long arg); +int unionfs_ioctl_queryfile(struct file *file, unsigned int cmd, + unsigned long arg); + +#ifdef CONFIG_UNION_FS_XATTR +/* Extended attribute functions. */ +extern void *unionfs_xattr_alloc(size_t size, size_t limit); +extern void unionfs_xattr_free(void *ptr, size_t size); + +extern ssize_t unionfs_getxattr(struct dentry *dentry, const char *name, + void *value, size_t size); +extern int unionfs_removexattr(struct dentry *dentry, const char *name); +extern ssize_t unionfs_listxattr(struct dentry *dentry, char *list, + size_t size); +extern int unionfs_setxattr(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags); +#endif /* CONFIG_UNION_FS_XATTR */ + +/* The root directory is unhashed, but isn't deleted. */ +static inline int d_deleted(struct dentry *d) +{ + return d_unhashed(d) && (d != d->d_sb->s_root); +} + +struct dentry *unionfs_lookup_backend(struct dentry *dentry, struct nameidata *nd, int lookupmode); + +#define IS_SET(sb, check_flag) ((check_flag) & MOUNT_FLAG(sb)) + +/* unionfs_permission, check if we should bypass error to facilitate copyup */ +#define IS_COPYUP_ERR(err) ((err) == -EROFS) + +/* unionfs_open, check if we need to copyup the file */ +#define OPEN_WRITE_FLAGS (O_WRONLY | O_RDWR | O_APPEND) +#define IS_WRITE_FLAG(flag) ((flag) & OPEN_WRITE_FLAGS) + +static inline int branchperms(const struct super_block *sb, int index) +{ + BUG_ON(index < 0); + + return UNIONFS_SB(sb)->data[index].branchperms; +} + +static inline int set_branchperms(struct super_block *sb, int index, int perms) +{ + BUG_ON(index < 0); + + UNIONFS_SB(sb)->data[index].branchperms = perms; + + return perms; +} + +/* Is this file on a read-only branch? */ +static inline int is_robranch_super(const struct super_block *sb, int index) +{ + return (!(branchperms(sb, index) & MAY_WRITE)) ? -EROFS : 0; +} + +/* Is this file on a read-only branch? */ +static inline int is_robranch_idx(const struct dentry *dentry, int index) +{ + int err = 0; + + BUG_ON(index < 0); + + if ((!(branchperms(dentry->d_sb, index) & MAY_WRITE)) || + IS_RDONLY(unionfs_lower_dentry_idx(dentry, index)->d_inode)) + err = -EROFS; + + return err; +} + +static inline int is_robranch(const struct dentry *dentry) +{ + int index; + + index = UNIONFS_D(dentry)->bstart; + BUG_ON(index < 0); + + return is_robranch_idx(dentry, index); +} + +/* What do we use for whiteouts. */ +#define UNIONFS_WHPFX ".wh." +#define UNIONFS_WHLEN 4 +/* If a directory contains this file, then it is opaque. We start with the + * .wh. flag so that it is blocked by lookup. + */ +#define UNIONFS_DIR_OPAQUE_NAME "__dir_opaque" +#define UNIONFS_DIR_OPAQUE UNIONFS_WHPFX UNIONFS_DIR_OPAQUE_NAME + +#define VALID_MOUNT_FLAGS (0) + +#ifndef DEFAULT_POLLMASK +#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM) +#endif + +/* + * EXTERNALS: + */ +extern char *alloc_whname(const char *name, int len); + +/* These two functions are here because it is kind of daft to copy and paste the + * contents of the two functions to 32+ places in unionfs + */ +static inline struct dentry *lock_parent(struct dentry *dentry) +{ + struct dentry *dir = dget(dentry->d_parent); + + mutex_lock(&dir->d_inode->i_mutex); + return dir; +} + +static inline void unlock_dir(struct dentry *dir) +{ + mutex_unlock(&dir->d_inode->i_mutex); + dput(dir); +} + +extern int make_dir_opaque(struct dentry *dir, int bindex); + +#endif /* not _UNION_H_ */ + diff --git a/fs/unionfs/unlink.c b/fs/unionfs/unlink.c new file mode 100644 index 0000000..f5b250a --- /dev/null +++ b/fs/unionfs/unlink.c @@ -0,0 +1,162 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* unlink a file by creating a whiteout */ +static int unionfs_unlink_whiteout(struct inode *dir, struct dentry *dentry) +{ + struct dentry *hidden_dentry; + struct dentry *hidden_dir_dentry; + int bindex; + int err = 0; + + if ((err = unionfs_partial_lookup(dentry))) + goto out; + + bindex = dbstart(dentry); + + hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!hidden_dentry) + goto out; + + hidden_dir_dentry = lock_parent(hidden_dentry); + + /* avoid destroying the hidden inode if the file is in use */ + dget(hidden_dentry); + if (!(err = is_robranch_super(dentry->d_sb, bindex))) + err = vfs_unlink(hidden_dir_dentry->d_inode, hidden_dentry); + dput(hidden_dentry); + fsstack_copy_attr_times(dir, hidden_dir_dentry->d_inode); + unlock_dir(hidden_dir_dentry); + + if (err && !IS_COPYUP_ERR(err)) + goto out; + + if (err) { + if (dbstart(dentry) == 0) + goto out; + + err = create_whiteout(dentry, dbstart(dentry) - 1); + } else if (dbopaque(dentry) != -1) + /* There is a hidden lower-priority file with the same name. */ + err = create_whiteout(dentry, dbopaque(dentry)); + else + err = create_whiteout(dentry, dbstart(dentry)); + +out: + if (!err) + dentry->d_inode->i_nlink--; + + /* We don't want to leave negative leftover dentries for revalidate. */ + if (!err && (dbopaque(dentry) != -1)) + update_bstart(dentry); + + return err; +} + +int unionfs_unlink(struct inode *dir, struct dentry *dentry) +{ + int err = 0; + + unionfs_lock_dentry(dentry); + + err = unionfs_unlink_whiteout(dir, dentry); + /* call d_drop so the system "forgets" about us */ + if (!err) + d_drop(dentry); + + unionfs_unlock_dentry(dentry); + return err; +} + +static int unionfs_rmdir_first(struct inode *dir, struct dentry *dentry, + struct unionfs_dir_state *namelist) +{ + int err; + struct dentry *hidden_dentry; + struct dentry *hidden_dir_dentry = NULL; + + /* Here we need to remove whiteout entries. */ + err = delete_whiteouts(dentry, dbstart(dentry), namelist); + if (err) + goto out; + + hidden_dentry = unionfs_lower_dentry(dentry); + + hidden_dir_dentry = lock_parent(hidden_dentry); + + /* avoid destroying the hidden inode if the file is in use */ + dget(hidden_dentry); + if (!(err = is_robranch(dentry))) + err = vfs_rmdir(hidden_dir_dentry->d_inode, hidden_dentry); + dput(hidden_dentry); + + fsstack_copy_attr_times(dir, hidden_dir_dentry->d_inode); + /* propagate number of hard-links */ + dentry->d_inode->i_nlink = unionfs_get_nlinks(dentry->d_inode); + +out: + if (hidden_dir_dentry) + unlock_dir(hidden_dir_dentry); + return err; +} + +int unionfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + int err = 0; + struct unionfs_dir_state *namelist = NULL; + + unionfs_lock_dentry(dentry); + + /* check if this unionfs directory is empty or not */ + err = check_empty(dentry, &namelist); + if (err) + goto out; + + err = unionfs_rmdir_first(dir, dentry, namelist); + /* create whiteout */ + if (!err) + err = create_whiteout(dentry, dbstart(dentry)); + else { + int new_err; + + if (dbstart(dentry) == 0) + goto out; + + /* exit if the error returned was NOT -EROFS */ + if (!IS_COPYUP_ERR(err)) + goto out; + + new_err = create_whiteout(dentry, dbstart(dentry) - 1); + if (new_err != -EEXIST) + err = new_err; + } + +out: + /* call d_drop so the system "forgets" about us */ + if (!err) + d_drop(dentry); + + if (namelist) + free_rdstate(namelist); + + unionfs_unlock_dentry(dentry); + return err; +} + diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c new file mode 100644 index 0000000..d57f079 --- /dev/null +++ b/fs/unionfs/xattr.c @@ -0,0 +1,123 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of State University of New York* + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* This is lifted from fs/xattr.c */ +void *unionfs_xattr_alloc(size_t size, size_t limit) +{ + void *ptr; + + if (size > limit) + return ERR_PTR(-E2BIG); + + if (!size) /* size request, no buffer is needed */ + return NULL; + else if (size <= PAGE_SIZE) + ptr = kmalloc(size, GFP_KERNEL); + else + ptr = vmalloc(size); + if (!ptr) + return ERR_PTR(-ENOMEM); + return ptr; +} + +void unionfs_xattr_free(void *ptr, size_t size) +{ + if (!size) /* size request, no buffer was needed */ + return; + else if (size <= PAGE_SIZE) + kfree(ptr); + else + vfree(ptr); +} + +/* BKL held by caller. + * dentry->d_inode->i_mutex locked + */ +ssize_t unionfs_getxattr(struct dentry * dentry, const char *name, void *value, + size_t size) +{ + struct dentry *hidden_dentry = NULL; + int err = -EOPNOTSUPP; + + unionfs_lock_dentry(dentry); + + hidden_dentry = unionfs_lower_dentry(dentry); + + err = vfs_getxattr(hidden_dentry, (char*) name, value, size); + + unionfs_unlock_dentry(dentry); + return err; +} + +/* BKL held by caller. + * dentry->d_inode->i_mutex locked + */ +int unionfs_setxattr(struct dentry *dentry, const char *name, const void *value, + size_t size, int flags) +{ + struct dentry *hidden_dentry = NULL; + int err = -EOPNOTSUPP; + + unionfs_lock_dentry(dentry); + hidden_dentry = unionfs_lower_dentry(dentry); + + err = vfs_setxattr(hidden_dentry, (char*) name, (void*) value, size, flags); + + unionfs_unlock_dentry(dentry); + return err; +} + +/* BKL held by caller. + * dentry->d_inode->i_mutex locked + */ +int unionfs_removexattr(struct dentry *dentry, const char *name) +{ + struct dentry *hidden_dentry = NULL; + int err = -EOPNOTSUPP; + + unionfs_lock_dentry(dentry); + hidden_dentry = unionfs_lower_dentry(dentry); + + err = vfs_removexattr(hidden_dentry, (char*) name); + + unionfs_unlock_dentry(dentry); + return err; +} + +/* BKL held by caller. + * dentry->d_inode->i_mutex locked + */ +ssize_t unionfs_listxattr(struct dentry * dentry, char *list, size_t size) +{ + struct dentry *hidden_dentry = NULL; + int err = -EOPNOTSUPP; + char *encoded_list = NULL; + + unionfs_lock_dentry(dentry); + + hidden_dentry = unionfs_lower_dentry(dentry); + + encoded_list = list; + err = vfs_listxattr(hidden_dentry, encoded_list, size); + + unionfs_unlock_dentry(dentry); + return err; +} + diff --git a/include/linux/magic.h b/include/linux/magic.h index b32c8a9..64ad0b7 100644 --- a/include/linux/magic.h +++ b/include/linux/magic.h @@ -34,6 +34,8 @@ #define REISERFS_SUPER_MAGIC_STRING "ReI #define REISER2FS_SUPER_MAGIC_STRING "ReIsEr2Fs" #define REISER2FS_JR_SUPER_MAGIC_STRING "ReIsEr3Fs" +#define UNIONFS_SUPER_MAGIC 0xf15f083d + #define SMB_SUPER_MAGIC 0x517B #define USBDEVICE_SUPER_MAGIC 0x9fa2 diff --git a/include/linux/namei.h b/include/linux/namei.h index d39a5a6..941be96 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -81,7 +81,15 @@ extern struct file *lookup_instantiate_f extern struct file *nameidata_to_filp(struct nameidata *nd, int flags); extern void release_open_intent(struct nameidata *); -extern struct dentry * lookup_one_len(const char *, struct dentry *, int); +extern struct dentry *lookup_one_len_nd(const char *, + struct dentry *, int, struct nameidata *); + +/* SMP-safe */ +static inline struct dentry *lookup_one_len(const char *name, + struct dentry *dir, int len) +{ + return lookup_one_len_nd(name, dir, len, NULL); +} extern int follow_down(struct vfsmount **, struct dentry **); extern int follow_up(struct vfsmount **, struct dentry **); diff --git a/include/linux/union_fs.h b/include/linux/union_fs.h new file mode 100644 index 0000000..b724031 --- /dev/null +++ b/include/linux/union_fs.h @@ -0,0 +1,18 @@ +#ifndef _LINUX_UNION_FS_H +#define _LINUX_UNION_FS_H + +#define UNIONFS_VERSION "2.0" +/* + * DEFINITIONS FOR USER AND KERNEL CODE: + */ +# define UNIONFS_IOCTL_INCGEN _IOR(0x15, 11, int) +# define UNIONFS_IOCTL_QUERYFILE _IOR(0x15, 15, int) + +/* We don't support normal remount, but unionctl uses it. */ +# define UNIONFS_REMOUNT_MAGIC 0x4a5a4380 + +/* should be at least LAST_USED_UNIONFS_PERMISSION<<1 */ +#define MAY_NFSRO 16 + +#endif /* _LINUX_UNIONFS_H */ +