From: Akira Fujita Subject: [RFC][PATCH 6/9]ext4: Add the EXT4_IOC_FREE_BLOCKS_INFO ioctl Date: Fri, 24 Oct 2008 19:09:55 +0900 Message-ID: <49019EF3.3020501@rs.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org To: linux-ext4@vger.kernel.org, Theodore Tso , Mingming Cao Return-path: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org ext4: online defrag -- Add the EXT4_IOC_FREE_BLOCKS_INFO ioctl. From: Akira Fujita The EXT4_IOC_FREE_BLOCKS_INFO ioctl gets free extents information of the target block group. This ioctl is used only in the force defrag (-f). Defragger calculates the victim extents (which will be moved into other block group in order to make contiguous free space for the target file) based on used/unused extents information. ext4_defrag_fblocks_distribution() was renamed as ext4_mb_search_free_extents() and moved into mballoc.c. Because it uses ext4_buddy structure. Signed-off-by: Akira Fujita Signed-off-by: Takashi Sato --- fs/ext4/ext4.h | 27 +++++++++++++++++ fs/ext4/ioctl.c | 20 +++++++++++++ fs/ext4/mballoc.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 128 insertions(+), 0 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 94c4186..f7b092d 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -304,6 +304,7 @@ struct ext4_new_group_data { /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */ #define EXT4_IOC_DEFRAG _IOW('f', 15, struct ext4_ext_defrag_data) #define EXT4_IOC_SUPER_INFO _IOR('f', 16, struct ext4_super_block) +#define EXT4_IOC_FREE_BLOCKS_INFO _IOWR('f', 17, struct ext4_extents_info) /* * ioctl commands in 32 bit emulation @@ -321,12 +322,36 @@ struct ext4_new_group_data { #define EXT4_IOC32_GETVERSION_OLD FS_IOC32_GETVERSION #define EXT4_IOC32_SETVERSION_OLD FS_IOC32_SETVERSION +/* + * The following four macros are used for the defrag force mode. + * + * DEFRAG_MAX_ENT: the maximum number of extents for exchanging between + * kernel-space and user-space per an ioctl + */ +#define DEFRAG_MAX_ENT 32 + +struct ext4_extent_data { + ext4_lblk_t block; /* start logical block number */ + ext4_fsblk_t start; /* start physical block number */ + int len; /* blocks count */ +}; + 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 */ }; +struct ext4_extents_info { + unsigned long long ino; /* inode number */ + int max_entries; /* maximum extents count */ + int entries; /* extent number/count */ + ext4_lblk_t f_offset; /* file offset */ + ext4_grpblk_t g_offset; /* group offset */ + ext4_fsblk_t goal; /* block offset for allocation */ + struct ext4_extent_data ext[DEFRAG_MAX_ENT]; +}; + #define EXT4_TRANS_META_BLOCKS 4 /* bitmap + group desc + sb + inode */ /* @@ -1069,6 +1094,8 @@ extern int ext4_mb_add_more_groupinfo(struct super_block *sb, ext4_group_t i, struct ext4_group_desc *desc); extern void ext4_mb_update_group_info(struct ext4_group_info *grp, ext4_grpblk_t add); +extern int ext4_mb_search_free_extents(struct inode *inode, + struct ext4_extents_info *ext_info); /* inode.c */ diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index f8ce89b..5709574 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -256,6 +256,26 @@ setversion_out: return 0; } + case EXT4_IOC_FREE_BLOCKS_INFO: { + struct ext4_extents_info ext_info; + int err; + + if (copy_from_user(&ext_info, + (struct ext4_extents_info __user *)arg, + sizeof(ext_info))) + return -EFAULT; + + BUG_ON(ext_info.ino != inode->i_ino); + + err = ext4_mb_search_free_extents(inode, &ext_info); + + if (!err) + err = copy_to_user( + (struct ext4_extents_info __user *)arg, + &ext_info, sizeof(ext_info)); + return err; + } + case EXT4_IOC_GROUP_ADD: { struct ext4_new_group_data input; struct super_block *sb = inode->i_sb; diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index dfe17a1..eebcf7c 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4654,3 +4654,84 @@ error_return: kmem_cache_free(ext4_ac_cachep, ac); return; } + +/** + * ext4_mb_search_free_extents + * - Search free extents in the block group where target inode is located + * + * @inode: target inode + * @ext_info: ext4_extents_info is used to store free extents + * + * This function returns 0 if succeed, otherwise returns error value. + */ +int +ext4_mb_search_free_extents(struct inode *inode, + struct ext4_extents_info *ext_info) +{ + struct super_block *sb = inode->i_sb; + struct ext4_buddy e4b; + ext4_group_t group_no; + ext4_grpblk_t start, end; + ext4_fsblk_t start_block = 0; + int i, err; + int num = 0; + int len = 0; + int block_set = 0; + int extra_block = 0; + + if (!sb) { + printk(KERN_ERR "ext4 defrag: Non-existent device\n"); + return -ENOSPC; + } + + group_no = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb); + start = ext_info->g_offset; + end = EXT4_BLOCKS_PER_GROUP(sb) - 1; + + err = ext4_mb_load_buddy(sb, group_no, &e4b); + if (err) + return err; + + /* We consider about the boot block if bs = 1k */ + if (sb->s_blocksize == 1024) + extra_block = 1; + + ext4_lock_group(sb, group_no); + + for (i = start; i <= end ; i++) { + if (!mb_test_bit(i, e4b.bd_bitmap)) { + len++; + /* + * Reset start_block if the free block is + * the head of region. + */ + if (!block_set) { + start_block = + i + group_no * EXT4_BLOCKS_PER_GROUP(sb) + + extra_block; + block_set = 1; + } + } else if (len) { + ext_info->ext[num].start = start_block; + ext_info->ext[num].len = len; + num++; + len = 0; + block_set = 0; + if (num == ext_info->max_entries) { + ext_info->g_offset = i + 1; + break; + } + } + if (i == end && len) { + ext_info->ext[num].start = start_block; + ext_info->ext[num].len = len; + num++; + } + } + ext_info->entries = num; + + ext4_unlock_group(sb, group_no); + ext4_mb_release_desc(&e4b); + + return err; +}