Re: [PATCH 02/14] xfs: fix rounding in xfs_free_file_space

Brian Foster
2013-05-20T17:58:54Z

On 05/19/2013 07:51 PM, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> The offset passed into xfs_free_file_space() needs to be rounded
> down to a certain size, but the rounding mask is built by a 32 bit
> variable. Hence the mask will always mask off the upper 32 bits of
> the offset and lead to incorrect writeback and invalidation ranges.
>
> This is not actually exposed as a bug because we writeback and
> invalidate from the rounded offset to the end of the file, and hence
> the offset we are actually punching a hole out of will always be
> covered by the code. This needs fixing, however, if we ever want to
> use exact ranges for writeback/invalidation here...
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---

Looks good to me.

Reviewed-by: Brian Foster <bfoster@redhat.com>

> fs/xfs/xfs_vnodeops.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
> index 1501f4f..0176bb2 100644
> --- a/fs/xfs/xfs_vnodeops.c
> +++ b/fs/xfs/xfs_vnodeops.c
> @@ -1453,7 +1453,7 @@ xfs_free_file_space(
> xfs_mount_t *mp;
> int nimap;
> uint resblks;
> - uint rounding;
> + xfs_off_t rounding;
> int rt;
> xfs_fileoff_t startoffset_fsb;
> xfs_trans_t *tp;
> @@ -1482,7 +1482,7 @@ xfs_free_file_space(
> inode_dio_wait(VFS_I(ip));
> }
>
> - rounding = max_t(uint, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
> + rounding = max_t(xfs_off_t, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
> ioffset = offset & ~(rounding - 1);
> error = -filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
> ioffset, -1);