From 105664df51648d6376bda2895a890e786d0426ee Mon Sep 17 00:00:00 2001 From: Calvin Owens Date: Fri, 31 Mar 2017 07:57:55 -0700 Subject: [PATCH] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will round the file size up to the nearest multiple of PAGE_SIZE: calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1 calvinow@vm-disks/generic-xfs-1 ~$ stat test Size: 2048 Blocks: 8 IO Block: 4096 regular file calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test calvinow@vm-disks/generic-xfs-1 ~$ stat test Size: 4096 Blocks: 8 IO Block: 4096 regular file Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers don't enforce that [pos,offset) lies strictly on [0,i_size) when being called from xfs_free_file_space(), so by "leaking" these ranges into xfs_zero_range() we get this buggy behavior. Fix this by reintroducing the checks xfs_zero_remaining_bytes() did against i_size at the bottom of xfs_free_file_space(). Reported-by: Aaron Gao Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") Cc: Christoph Hellwig Cc: Brian Foster Cc: # 4.8+ Signed-off-by: Calvin Owens Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_bmap_util.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 8b75dcea5966..828532ce0adc 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1311,8 +1311,16 @@ xfs_free_file_space( /* * Now that we've unmap all full blocks we'll have to zero out any * partial block at the beginning and/or end. xfs_zero_range is - * smart enough to skip any holes, including those we just created. + * smart enough to skip any holes, including those we just created, + * but we must take care not to zero beyond EOF and enlarge i_size. */ + + if (offset >= XFS_ISIZE(ip)) + return 0; + + if (offset + len > XFS_ISIZE(ip)) + len = XFS_ISIZE(ip) - offset; + return xfs_zero_range(ip, offset, len, NULL); }