From 12870f1c9b2de7d475d22e73fd7db1b418599725 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Sat, 15 Feb 2014 15:55:58 +0000 Subject: [PATCH] Btrfs: don't insert useless holes when punching beyond the inode's size If we punch beyond the size of an inode, we'll correctly remove any prealloc extents, but we'll also insert file extent items representing holes (disk bytenr == 0) that start with a key offset that lies beyond the inode's size and are not contiguous with the last file extent item. Example: $XFS_IO_PROG -f -c "truncate 118811" $SCRATCH_MNT/foo $XFS_IO_PROG -c "fpunch 582007 864596" $SCRATCH_MNT/foo $XFS_IO_PROG -c "pwrite -S 0x0d -b 39987 92267 39987" $SCRATCH_MNT/foo btrfs-debug-tree output: item 4 key (257 INODE_ITEM 0) itemoff 15885 itemsize 160 inode generation 6 transid 6 size 132254 block group 0 mode 100600 links 1 item 5 key (257 INODE_REF 256) itemoff 15872 itemsize 13 inode ref index 2 namelen 3 name: foo item 6 key (257 EXTENT_DATA 0) itemoff 15819 itemsize 53 extent data disk byte 0 nr 0 gen 6 extent data offset 0 nr 90112 ram 122880 extent compression 0 item 7 key (257 EXTENT_DATA 90112) itemoff 15766 itemsize 53 extent data disk byte 12845056 nr 4096 gen 6 extent data offset 0 nr 45056 ram 45056 extent compression 2 item 8 key (257 EXTENT_DATA 585728) itemoff 15713 itemsize 53 extent data disk byte 0 nr 0 gen 6 extent data offset 0 nr 860160 ram 860160 extent compression 0 The last extent item, which represents a hole, is useless as it lies beyond the inode's size. Signed-off-by: Filipe David Borba Manana Signed-off-by: Josef Bacik --- fs/btrfs/file.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 6acccc4a7f2a..762ca32bd988 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2168,6 +2168,7 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) bool same_page = ((offset >> PAGE_CACHE_SHIFT) == ((offset + len - 1) >> PAGE_CACHE_SHIFT)); bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES); + u64 ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE); ret = btrfs_wait_ordered_range(inode, offset, len); if (ret) @@ -2183,14 +2184,14 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) * entire page. */ if (same_page && len < PAGE_CACHE_SIZE) { - if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) + if (offset < ino_size) ret = btrfs_truncate_page(inode, offset, len, 0); mutex_unlock(&inode->i_mutex); return ret; } /* zero back part of the first page */ - if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) { + if (offset < ino_size) { ret = btrfs_truncate_page(inode, offset, 0, 0); if (ret) { mutex_unlock(&inode->i_mutex); @@ -2199,7 +2200,7 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) } /* zero the front end of the last page */ - if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) { + if (offset + len < ino_size) { ret = btrfs_truncate_page(inode, offset + len, 0, 1); if (ret) { mutex_unlock(&inode->i_mutex); @@ -2288,10 +2289,13 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) trans->block_rsv = &root->fs_info->trans_block_rsv; - ret = fill_holes(trans, inode, path, cur_offset, drop_end); - if (ret) { - err = ret; - break; + if (cur_offset < ino_size) { + ret = fill_holes(trans, inode, path, cur_offset, + drop_end); + if (ret) { + err = ret; + break; + } } cur_offset = drop_end; @@ -2324,10 +2328,12 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) } trans->block_rsv = &root->fs_info->trans_block_rsv; - ret = fill_holes(trans, inode, path, cur_offset, drop_end); - if (ret) { - err = ret; - goto out_trans; + if (cur_offset < ino_size) { + ret = fill_holes(trans, inode, path, cur_offset, drop_end); + if (ret) { + err = ret; + goto out_trans; + } } out_trans: -- 2.20.1