From e1d227a42ea2b4664f94212bd1106b9a3413ffb8 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Mon, 8 Jun 2015 15:05:25 -0700 Subject: [PATCH] btrfs: Handle unaligned length in extent_same The extent-same code rejects requests with an unaligned length. This poses a problem when we want to dedupe the tail extent of files as we skip cloning the portion between i_size and the extent boundary. If we don't clone the entire extent, it won't be deleted. So the combination of these behaviors winds up giving us worst-case dedupe on many files. We can fix this by allowing a length that extents to i_size and internally aligining those to the end of the block. This is what btrfs_ioctl_clone() so we can just copy that check over. Signed-off-by: Mark Fasheh Signed-off-by: Chris Mason --- fs/btrfs/ioctl.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 9041f154cc32..c86b835da7a8 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2889,12 +2889,19 @@ static int btrfs_cmp_data(struct inode *src, u64 loff, struct inode *dst, return ret; } -static int extent_same_check_offsets(struct inode *inode, u64 off, u64 len) +static int extent_same_check_offsets(struct inode *inode, u64 off, u64 *plen, + u64 olen) { + u64 len = *plen; u64 bs = BTRFS_I(inode)->root->fs_info->sb->s_blocksize; - if (off + len > inode->i_size || off + len < off) + if (off + olen > inode->i_size || off + olen < off) return -EINVAL; + + /* if we extend to eof, continue to block boundary */ + if (off + len == inode->i_size) + *plen = len = ALIGN(inode->i_size, bs) - off; + /* Check that we are block aligned - btrfs_clone() requires this */ if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs)) return -EINVAL; @@ -2902,10 +2909,11 @@ static int extent_same_check_offsets(struct inode *inode, u64 off, u64 len) return 0; } -static int btrfs_extent_same(struct inode *src, u64 loff, u64 len, +static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen, struct inode *dst, u64 dst_loff) { int ret; + u64 len = olen; /* * btrfs_clone() can't handle extents in the same file @@ -2920,11 +2928,11 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 len, btrfs_double_lock(src, loff, dst, dst_loff, len); - ret = extent_same_check_offsets(src, loff, len); + ret = extent_same_check_offsets(src, loff, &len, olen); if (ret) goto out_unlock; - ret = extent_same_check_offsets(dst, dst_loff, len); + ret = extent_same_check_offsets(dst, dst_loff, &len, olen); if (ret) goto out_unlock; @@ -2937,7 +2945,7 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 len, ret = btrfs_cmp_data(src, loff, dst, dst_loff, len); if (ret == 0) - ret = btrfs_clone(src, dst, loff, len, len, dst_loff); + ret = btrfs_clone(src, dst, loff, olen, len, dst_loff); out_unlock: btrfs_double_unlock(src, loff, dst, dst_loff, len);