ext4: online defrag-- Main function of defrag and ioctl implementation From: Akira Fujita Create the temporary inode and do defrag per defrag_size (defalut 64MB). Signed-off-by: Akira Fujita Signed-off-by: Takashi Sato --- fs/ext4/Makefile | 2 fs/ext4/defrag.c | 448 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/ext4/ext4.h | 18 + fs/ext4/ext4_extents.h | 2 fs/ext4/extents.c | 2 fs/ext4/ioctl.c | 3 6 files changed, 473 insertions(+), 2 deletions(-) Index: linux-2.6.26-rc9/fs/ext4/Makefile =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/Makefile 2008-07-11 16:04:25.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/Makefile 2008-07-11 16:05:18.000000000 -0700 @@ -6,7 +6,7 @@ obj-$(CONFIG_EXT4DEV_FS) += ext4dev.o ext4dev-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \ ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \ - ext4_jbd2.o migrate.o mballoc.o + ext4_jbd2.o migrate.o mballoc.o defrag.o ext4dev-$(CONFIG_EXT4DEV_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o ext4dev-$(CONFIG_EXT4DEV_FS_POSIX_ACL) += acl.o Index: linux-2.6.26-rc9/fs/ext4/defrag.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.26-rc9/fs/ext4/defrag.c 2008-07-11 16:05:18.000000000 -0700 @@ -0,0 +1,448 @@ +/* + * Copyright (c) 2008, NEC Software Tohoku, Ltd. + * Written by Takashi Sato + * Akira Fujita + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2.1 of the GNU Lesser General Public License + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +/* Online defragmentation for EXT4 */ + +#include +#include "ext4_jbd2.h" +#include "ext4_extents.h" +#include "group.h" + +/** + * ext4_defrag_next_extent - Search for the next extent and set it to "extent" + * + * @inode: inode which is searched + * @path: this will obtain data for the next extent + * @extent: pointer to the next extent we have just gotten + * + * This function returns 0 or 1(last entry) if succeed, otherwise + * returns -EIO. + */ +static int +ext4_defrag_next_extent(struct inode *inode, struct ext4_ext_path *path, + struct ext4_extent **extent) +{ + return 0; +} + +int ext4_defrag_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, + unsigned long arg) +{ + int err = 0; + + if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) { + printk(KERN_ERR "ext4 defrag: ino[%lu] is not extents " + "based file\n", inode->i_ino); + return -EOPNOTSUPP; + } + + if (cmd == EXT4_IOC_DEFRAG) { + struct ext4_ext_defrag_data defrag; + struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es; + + if (!capable(CAP_DAC_OVERRIDE)) { + if ((inode->i_mode & S_IRUSR) != S_IRUSR) + return -EACCES; + if (current->fsuid != inode->i_uid) + return -EACCES; + } + + if (copy_from_user(&defrag, + (struct ext4_ext_defrag_data __user *)arg, + sizeof(defrag))) + return -EFAULT; + + /* Check goal offset if goal offset was given from userspace */ + if (defrag.goal != -1 && + ext4_blocks_count(es) <= defrag.goal) { + printk(KERN_ERR "ext4 defrag: Invalid goal offset" + " %llu, you can set goal offset up to %llu\n", + defrag.goal, ext4_blocks_count(es) - 1); + return -EINVAL; + } + + err = ext4_defrag(filp, defrag.start_offset, + defrag.defrag_size); + } + + return err; +} + +/** + * ext4_defrag_partial - Defrag a file per page + * + * @tmp_inode: temporary inode + * @filp: pointer to file + * @org_offset: page index on original file + * @dest_offset: page index on temporary file + * + * + * This function returns 0 if succeed, otherwise returns error value. + */ +static int +ext4_defrag_partial(struct inode *tmp_inode, struct file *filp, + pgoff_t org_offset, pgoff_t dest_offset) +{ + return 0; +} + +/** + * ext4_defrag_new_extent_tree - Get contiguous blocks and build an extent tree + * + * @org_inode: original inode + * @tmp_inode: temporary inode + * @org_path: indicating the original inode's extent + * @tar_start: starting offset to allocate in blocks + * @tar_blocks: the number of blocks to allocate + * @iblock: file related offset + * + * + * This function returns the value as below: + * 0 (succeed) + * 1 (not improved) + * negative value (error case) + */ +static int +ext4_defrag_new_extent_tree(struct inode *org_inode, struct inode *tmp_inode, + struct ext4_ext_path *org_path, ext4_lblk_t tar_start, + ext4_lblk_t tar_blocks, ext4_lblk_t iblock) +{ + return 0; +} + +/** + * ext4_defrag_check - Check the enviroment whether a defrag can be done + * + * @org_inode: original inode + * @defrag_size: size of defrag in blocks + * + * This function returns 0 if succeed, otherwise returns error value. + */ +static int +ext4_defrag_check(struct inode *org_inode, ext4_lblk_t defrag_size) +{ + + /* ext4 online defrag supports only 4KB block size */ + if (org_inode->i_sb->s_blocksize != DEFRAG_BLOCK_SIZE) { + printk(KERN_ERR "ext4 defrag: ext4 online defrag supports " + "only 4KB block size for the moment.\n"); + return -EOPNOTSUPP; + } + + /* ext4 online defrag needs mballoc mount option. */ + if (!test_opt(org_inode->i_sb, MBALLOC)) { + printk(KERN_ERR "ext4 defrag: multiblock allocation " + "is disabled\n"); + return -EOPNOTSUPP; + } + + return 0; +} + +/** + * ext4_defrag_init_tmp_inode - Create a temporary inode + * + * @org_inode: original inode + * + * This function returns pointer to the struct inode if succeed, + * otherwise returns error value. + */ +static struct inode * +ext4_defrag_init_tmp_inode(struct inode *org_inode) +{ + handle_t *handle; + struct inode *tmp_inode; + + handle = ext4_journal_start(org_inode, + EXT4_DATA_TRANS_BLOCKS(org_inode->i_sb) + + EXT4_INDEX_EXTRA_TRANS_BLOCKS + 4 + + 2 * EXT4_QUOTA_INIT_BLOCKS(org_inode->i_sb)); + if (IS_ERR(handle)) + /* Return error code */ + return (struct inode *)handle; + + tmp_inode = ext4_new_inode(handle, + org_inode->i_sb->s_root->d_inode, S_IFREG); + if (IS_ERR(tmp_inode)) + goto out; + + i_size_write(tmp_inode, i_size_read(org_inode)); + tmp_inode->i_nlink = 0; + ext4_ext_tree_init(handle, tmp_inode); + ext4_orphan_add(handle, tmp_inode); + +out: + ext4_journal_stop(handle); + + return tmp_inode; +} + +/** + * ext4_defrag - Defrag the specified range of a file + * + * If no-option is specified, ext4_defrag() proceeds the following order. + * 1.ext4_defrag() calculates the block number where defrag terminates + * by the start block number(defrag_start) and the size of defraged data + * (defrag_size) specified as arguments. + * If the defrag_start points a hole, the extent's start offset pointed by + * ext_cur(current extent), holecheck_path, org_path are set after + * hole behind. + * 2.Continue step 3 to step 5, until the holecheck_path points to last_extent + * or the ext_cur exceeds the block_end which is last logical block number. + * 3.To get a length of continues area, call ext4_defrag_next_extent() + * specified with the ext_cur(initial value is holecheck_path) re-cursive, + * until find un-continuous extent, the start logical block number exceeds + * the block_end or the extent points to the last extent. + * 4.After determining the length of continuous block, + * allocates continuous blocks to a temporary inode + * by ext4_defrag_new_extent_tree(). + * 5.Exchange the original inode data with temporary inode data + * from page_offset to seq_end_page by page unit. + * The start page index of data are specified as arguments: + * the original inode is page_offset, the temporary inode is dest_offset. + * 6.Update holecheck_path and org_path to points a next proceeding extent, + * and release the temporary inode holding the original fragmented data. + * Then, returns to step 2. + * 7.Release holecheck_path, org_path and temporary inode, + * and returns the defrag_size which is the size of defraged data. + * The defrag_size is used for the command to calculate the file offset + * where a next defrag processing start. + * (Since the defrag command calls defrag_ioctl() by 64MB unit, + * a file bigger than 64MB calls defrag_ioctl many times.) + * + * @filp: pointer to file + * @block_start: starting offset to defrag in blocks + * @defrag_size: size of defrag in blocks + * + * This function returns the number of blocks if succeed, otherwise + * returns error value. + */ +int +ext4_defrag(struct file *filp, ext4_lblk_t block_start, + ext4_lblk_t defrag_size) +{ + struct inode *org_inode = filp->f_dentry->d_inode, *tmp_inode = NULL; + struct ext4_ext_path *org_path = NULL, *holecheck_path = NULL; + struct ext4_extent *ext_prev, *ext_cur, *ext_dummy; + ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0; + pgoff_t page_offset, seq_end_page, dest_offset; + int ret, depth, seq_extents, last_extent = 0; + + /* Check the filesystem enviroment whether defrag can be done */ + ret = ext4_defrag_check(org_inode, defrag_size); + if (ret < 0) + return ret; + + file_end = (org_inode->i_size - 1) >> org_inode->i_blkbits; + block_end = block_start + defrag_size - 1; + if (file_end < block_end) + defrag_size -= block_end - file_end; + + mutex_lock(&org_inode->i_mutex); + down_write(&EXT4_I(org_inode)->i_data_sem); + + org_path = ext4_ext_find_extent(org_inode, block_start, NULL); + if (IS_ERR(org_path)) { + ret = PTR_ERR(org_path); + org_path = NULL; + goto out; + } + + /* Get path structure to check the hole */ + holecheck_path = ext4_ext_find_extent(org_inode, block_start, NULL); + if (IS_ERR(holecheck_path)) { + ret = PTR_ERR(holecheck_path); + holecheck_path = NULL; + goto out; + } + + depth = ext_depth(org_inode); + ext_cur = holecheck_path[depth].p_ext; + if (ext_cur == NULL) + goto out; + + /* + * Get proper extent whose ee_block is beyond block_start + * if block_start was within the hole. + */ + if (le32_to_cpu(ext_cur->ee_block) + + le16_to_cpu(ext_cur->ee_len) - 1 < block_start) { + last_extent = ext4_defrag_next_extent(org_inode, + holecheck_path, &ext_cur); + if (last_extent < 0) { + ret = last_extent; + goto out; + } + last_extent = ext4_defrag_next_extent(org_inode, org_path, + &ext_dummy); + if (last_extent < 0) { + ret = last_extent; + goto out; + } + } + seq_extents = 1; + seq_start = le32_to_cpu(ext_cur->ee_block); + + /* No blocks within the specified range. */ + if (le32_to_cpu(ext_cur->ee_block) > block_end) { + printk(KERN_INFO "ext4 defrag: The specified range of file" + " may be the hole\n"); + goto out; + } + + /* Adjust start blocks */ + add_blocks = min(le32_to_cpu(ext_cur->ee_block) + + le16_to_cpu(ext_cur->ee_len), block_end + 1) - + max(le32_to_cpu(ext_cur->ee_block), block_start); + + while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) { + seq_blocks += add_blocks; + + /* Create a temporary inode to be exchanged data block */ + tmp_inode = ext4_defrag_init_tmp_inode(org_inode); + if (IS_ERR(tmp_inode)) { + ret = PTR_ERR(tmp_inode); + tmp_inode = NULL; + goto out; + } + + /* Adjust tail blocks */ + if (seq_start + seq_blocks - 1 > block_end) + seq_blocks = block_end - seq_start + 1; + + ext_prev = ext_cur; + last_extent = ext4_defrag_next_extent(org_inode, + holecheck_path, &ext_cur); + if (last_extent < 0) { + ret = last_extent; + break; + } + if (!last_extent) + seq_extents++; + add_blocks = le16_to_cpu(ext_cur->ee_len); + + /* + * Extend the length of contiguous block (seq_blocks) + * if extents are contiguous. + */ + if (le32_to_cpu(ext_prev->ee_block) + + le16_to_cpu(ext_prev->ee_len) == + le32_to_cpu(ext_cur->ee_block) && + block_end >= le32_to_cpu(ext_cur->ee_block) && + !last_extent) { + if (tmp_inode) { + iput(tmp_inode); + tmp_inode = NULL; + } + continue; + } + + /* Found an isolated block */ + if (seq_extents == 1) { + seq_start = le32_to_cpu(ext_cur->ee_block); + goto CLEANUP; + } + + ret = ext4_defrag_new_extent_tree(org_inode, tmp_inode, + org_path, seq_start, seq_blocks, + block_start); + + if (ret < 0) { + break; + } else if (ret == 1) { + ret = 0; + seq_start = le32_to_cpu(ext_cur->ee_block); + goto CLEANUP; + } + + page_offset = seq_start >> + (PAGE_CACHE_SHIFT - org_inode->i_blkbits); + dest_offset = 0; + seq_end_page = (seq_start + seq_blocks - 1) >> + (PAGE_CACHE_SHIFT - org_inode->i_blkbits); + seq_start = le32_to_cpu(ext_cur->ee_block); + + /* + * Discard all preallocations. + * This is provisional solution. + * When true ext4_mb_return_to_preallocation() is + * implemented, this will be removed. + */ + ext4_mb_discard_inode_preallocations(org_inode); + + while (page_offset <= seq_end_page) { + /* Swap original branches with new branches */ + ret = ext4_defrag_partial(tmp_inode, filp, + page_offset, dest_offset); + if (ret < 0) + goto out; + + page_offset++; + dest_offset++; + } + + /* Decrease buffer counter */ + if (holecheck_path) + ext4_ext_drop_refs(holecheck_path); + holecheck_path = ext4_ext_find_extent(org_inode, + seq_start, holecheck_path); + if (IS_ERR(holecheck_path)) { + ret = PTR_ERR(holecheck_path); + holecheck_path = NULL; + break; + } + depth = holecheck_path->p_depth; + +CLEANUP: + /* Decrease buffer counter */ + if (org_path) + ext4_ext_drop_refs(org_path); + org_path = ext4_ext_find_extent(org_inode, seq_start, org_path); + if (IS_ERR(org_path)) { + ret = PTR_ERR(org_path); + org_path = NULL; + break; + } + + ext_cur = holecheck_path[depth].p_ext; + add_blocks = le16_to_cpu(ext_cur->ee_len); + seq_blocks = 0; + dest_offset = 0; + seq_extents = 1; + + if (tmp_inode) { + iput(tmp_inode); + tmp_inode = NULL; + } + } + +out: + if (org_path) { + ext4_ext_drop_refs(org_path); + kfree(org_path); + } + if (holecheck_path) { + ext4_ext_drop_refs(holecheck_path); + kfree(holecheck_path); + } + + up_write(&EXT4_I(org_inode)->i_data_sem); + mutex_unlock(&org_inode->i_mutex); + + if (tmp_inode) + iput(tmp_inode); + + return (ret ? ret : defrag_size); +} Index: linux-2.6.26-rc9/fs/ext4/ext4.h =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/ext4.h 2008-07-11 16:05:15.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/ext4.h 2008-07-11 16:05:18.000000000 -0700 @@ -301,6 +301,7 @@ struct ext4_new_group_data { #define EXT4_IOC_GETRSVSZ _IOR('f', 5, long) #define EXT4_IOC_SETRSVSZ _IOW('f', 6, long) #define EXT4_IOC_MIGRATE _IO('f', 7) +#define EXT4_IOC_DEFRAG _IOW('f', 10, struct ext4_ext_defrag_data) /* * ioctl commands in 32 bit emulation @@ -318,6 +319,18 @@ struct ext4_new_group_data { #define EXT4_IOC32_GETVERSION_OLD FS_IOC32_GETVERSION #define EXT4_IOC32_SETVERSION_OLD FS_IOC32_SETVERSION +/* + * Will go away. + * ext4 online defrag supports only 4KB block size. + */ +#define DEFRAG_BLOCK_SIZE 4096 + +struct ext4_ext_defrag_data { + ext4_lblk_t start_offset; /* start offset to defrag in blocks */ + ext4_lblk_t defrag_size; /* size of defrag in blocks */ + ext4_fsblk_t goal; /* block offset for allocation */ +}; + /* * Mount options @@ -1124,6 +1137,11 @@ extern void ext4_inode_bitmap_set(struct struct ext4_group_desc *bg, ext4_fsblk_t blk); extern void ext4_inode_table_set(struct super_block *sb, struct ext4_group_desc *bg, ext4_fsblk_t blk); +/* defrag.c */ +extern int ext4_defrag(struct file *filp, ext4_lblk_t block_start, + ext4_lblk_t defrag_size); +extern int ext4_defrag_ioctl(struct inode *, struct file *, unsigned int, + unsigned long); static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es) { Index: linux-2.6.26-rc9/fs/ext4/ext4_extents.h =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/ext4_extents.h 2008-07-11 16:05:13.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/ext4_extents.h 2008-07-11 16:05:18.000000000 -0700 @@ -229,5 +229,7 @@ extern int ext4_ext_search_left(struct i extern int ext4_ext_search_right(struct inode *, struct ext4_ext_path *, ext4_lblk_t *, ext4_fsblk_t *); extern void ext4_ext_drop_refs(struct ext4_ext_path *); +extern ext4_fsblk_t ext_pblock(struct ext4_extent *ex); +extern void ext4_ext_drop_refs(struct ext4_ext_path *path); #endif /* _EXT4_EXTENTS */ Index: linux-2.6.26-rc9/fs/ext4/extents.c =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/extents.c 2008-07-11 16:05:17.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/extents.c 2008-07-11 16:05:18.000000000 -0700 @@ -48,7 +48,7 @@ * ext_pblock: * combine low and high parts of physical block number into ext4_fsblk_t */ -static ext4_fsblk_t ext_pblock(struct ext4_extent *ex) +ext4_fsblk_t ext_pblock(struct ext4_extent *ex) { ext4_fsblk_t block; Index: linux-2.6.26-rc9/fs/ext4/ioctl.c =================================================================== --- linux-2.6.26-rc9.orig/fs/ext4/ioctl.c 2008-07-11 16:04:26.000000000 -0700 +++ linux-2.6.26-rc9/fs/ext4/ioctl.c 2008-07-11 16:05:18.000000000 -0700 @@ -241,6 +241,9 @@ setversion_out: return err; } + case EXT4_IOC_DEFRAG: { + return ext4_defrag_ioctl(inode, filp, cmd, arg); + } case EXT4_IOC_GROUP_ADD: { struct ext4_new_group_data input; struct super_block *sb = inode->i_sb;