• Calvin Owens's avatar
    xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files · 3dd09d5a
    Calvin Owens authored
    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 3c2bdc91 ("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: default avatarAaron Gao <gzh@fb.com>
    Fixes: 3c2bdc91 ("xfs: kill xfs_zero_remaining_bytes")
    Cc: Christoph Hellwig <hch@lst.de>
    Cc: Brian Foster <bfoster@redhat.com>
    Cc: <stable@vger.kernel.org> # 4.8+
    Signed-off-by: default avatarCalvin Owens <calvinowens@fb.com>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    3dd09d5a
xfs_bmap_util.c 55.6 KB