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 Signed-off-by: Mingming Cao --- fs/ext4/defrag.c | 289 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/ext4/ext4.h | 19 +++ fs/ext4/ioctl.c | 3 3 files changed, 310 insertions(+), 1 deletion(-) Index: linux-2.6.26-rc1/fs/ext4/defrag.c =================================================================== --- linux-2.6.26-rc1.orig/fs/ext4/defrag.c 2008-05-05 17:10:19.000000000 -0700 +++ linux-2.6.26-rc1/fs/ext4/defrag.c 2008-05-05 17:10:20.000000000 -0700 @@ -1,3 +1,18 @@ +/* + * 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 @@ -74,6 +89,27 @@ ext4_defrag_next_extent(struct inode *in return 1; } +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)) + return -EINVAL; + + if (cmd == EXT4_IOC_DEFRAG) { + struct ext4_ext_defrag_data defrag; + + if (copy_from_user(&defrag, + (struct ext4_ext_defrag_data __user *)arg, + sizeof(defrag))) + return -EFAULT; + err = ext4_defrag(filp, defrag.start_offset, + defrag.defrag_size); + } + + return err; +} + /** * ext4_defrag_merge_across_blocks - Merge extents across leaf block * @@ -1022,3 +1058,256 @@ ext4_defrag_new_extent_tree(struct inode out: return ret; } + +/** + * ext4_defrag - Defrag the specified range of a file + * + * @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 succeeded, otherwise + * returns error value. + */ +int +ext4_defrag(struct file *filp, ext4_lblk_t block_start, + ext4_lblk_t defrag_size) +{ + struct inode *inode = filp->f_dentry->d_inode, *tmp_inode = NULL; + struct ext4_ext_path *path = NULL, *holecheck_path = NULL; + struct ext4_extent *ext_prev = NULL, *ext_cur = NULL, *ext_dummy = NULL; + handle_t *handle; + ext4_lblk_t block_end = block_start + defrag_size - 1; + ext4_lblk_t seq_blocks = 0, seq_start = 0; + ext4_lblk_t add_blocks = 0; + ext4_lblk_t file_end = (inode->i_size - 1) >> inode->i_blkbits; + pgoff_t page_offset = 0, dest_offset = 0, seq_end_page = 0; + int ret = 0, depth = 0, last_extent = 0, seq_extents = 0; + + /* ext4 online defrag supports only 4KB block size */ + if (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 -EINVAL; + } + + /* ext4 online defrag needs mballoc mount option. */ + if (!test_opt(inode->i_sb, MBALLOC)) { + printk(KERN_ERR "ext4 defrag: multiblock allocation " + "is disabled\n"); + return -EINVAL; + } + + if (file_end < block_end) + defrag_size -= block_end - file_end; + + mutex_lock(&inode->i_mutex); + down_write(&EXT4_I(inode)->i_data_sem); + + path = ext4_ext_find_extent(inode, block_start, NULL); + if (IS_ERR(path)) { + ret = PTR_ERR(path); + path = NULL; + goto out; + } + + /* Get path structure to check the hole */ + holecheck_path = ext4_ext_find_extent(inode, block_start, NULL); + if (IS_ERR(holecheck_path)) { + ret = PTR_ERR(holecheck_path); + holecheck_path = NULL; + goto out; + } + + depth = ext_depth(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(inode, holecheck_path, + &ext_cur); + if (last_extent < 0) { + ret = last_extent; + goto out; + } + last_extent = ext4_defrag_next_extent(inode, 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; + + handle = ext4_journal_start(inode, + EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + + EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 + + 2 * EXT4_QUOTA_INIT_BLOCKS(inode->i_sb) + 1); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + goto out; + } + tmp_inode = ext4_new_inode(handle, + inode->i_sb->s_root->d_inode, S_IFREG); + if (IS_ERR(tmp_inode)) { + ret = -ENOMEM; + ext4_journal_stop(handle); + tmp_inode = NULL; + goto out; + } + + i_size_write(tmp_inode, i_size_read(inode)); + tmp_inode->i_nlink = 0; + ext4_ext_tree_init(handle, tmp_inode); + ext4_orphan_add(handle, tmp_inode); + ext4_journal_stop(handle); + + /* 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(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(inode, tmp_inode, 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 - inode->i_blkbits); + seq_end_page = (seq_start + seq_blocks - 1) >> + (PAGE_CACHE_SHIFT - inode->i_blkbits); + + dest_offset = 0; + 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(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(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 (path) + ext4_ext_drop_refs(path); + path = ext4_ext_find_extent(inode, seq_start, path); + if (IS_ERR(path)) { + ret = PTR_ERR(path); + 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 (path) { + ext4_ext_drop_refs(path); + kfree(path); + } + if (holecheck_path) { + ext4_ext_drop_refs(holecheck_path); + kfree(holecheck_path); + } + + up_write(&EXT4_I(inode)->i_data_sem); + mutex_unlock(&inode->i_mutex); + + if (tmp_inode) + iput(tmp_inode); + + return (ret ? ret : defrag_size); +} Index: linux-2.6.26-rc1/fs/ext4/ext4.h =================================================================== --- linux-2.6.26-rc1.orig/fs/ext4/ext4.h 2008-05-05 17:10:19.000000000 -0700 +++ linux-2.6.26-rc1/fs/ext4/ext4.h 2008-05-05 17:10:20.000000000 -0700 @@ -298,6 +298,7 @@ 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 @@ -315,8 +316,19 @@ struct ext4_new_group_data { #define EXT4_IOC32_GETVERSION_OLD FS_IOC32_GETVERSION #define EXT4_IOC32_SETVERSION_OLD FS_IOC32_SETVERSION -#define EXT4_TRANS_META_BLOCKS 4 /* bitmap + group desc + sb + inode */ +/* + * 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 */ +}; + +#define EXT4_TRANS_META_BLOCKS 4 /* bitmap + group desc + sb + inode */ /* * Mount options @@ -1114,6 +1126,11 @@ extern void ext4_inode_table_set(struct struct ext4_group_desc *bg, ext4_fsblk_t blk); /* extents.c */ extern handle_t *ext4_ext_journal_restart(handle_t *handle, int needed); +/* 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-rc1/fs/ext4/ioctl.c =================================================================== --- linux-2.6.26-rc1.orig/fs/ext4/ioctl.c 2008-05-05 17:10:09.000000000 -0700 +++ linux-2.6.26-rc1/fs/ext4/ioctl.c 2008-05-05 17:10:20.000000000 -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;