Re: [PATCH v2] xfs: overflow in xfs_iomap_eof_align_last_fsb

Brian Foster
2014-12-02T16:24:52Z

On Mon, Dec 01, 2014 at 05:45:28PM -0500, Peter Watkins wrote:
> If extsize is set and new_last_fsb is larger than 32 bits, the
> roundup to extsize will overflow the align variable. Instead,
> combine alignments by rounding stripe size up to extsize.
>
> Signed-off-by: Peter Watkins <treestem@gmail.com>
> Reviewed-by: Nathaniel W. Turner <nate@houseofnate.net>
> ---

Looks fine to me:

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

> fs/xfs/xfs_iomap.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index afcf3c9..3fad071 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -52,7 +52,6 @@ xfs_iomap_eof_align_last_fsb(
> xfs_extlen_t extsize,
> xfs_fileoff_t *last_fsb)
> {
> - xfs_fileoff_t new_last_fsb = 0;
> xfs_extlen_t align = 0;
> int eof, error;
>
> @@ -70,8 +69,8 @@ xfs_iomap_eof_align_last_fsb(
> else if (mp->m_dalign)
> align = mp->m_dalign;
>
> - if (align && XFS_ISIZE(ip) >= XFS_FSB_TO_B(mp, align))
> - new_last_fsb = roundup_64(*last_fsb, align);
> + if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
> + align = 0;
> }
>
> /*
> @@ -79,14 +78,14 @@ xfs_iomap_eof_align_last_fsb(
> * (when file on a real-time subvolume or has di_extsize hint).
> */
> if (extsize) {
> - if (new_last_fsb)
> - align = roundup_64(new_last_fsb, extsize);
> + if (align)
> + align = roundup_64(align, extsize);
> else
> align = extsize;
> - new_last_fsb = roundup_64(*last_fsb, align);
> }
>
> - if (new_last_fsb) {
> + if (align) {
> + xfs_fileoff_t new_last_fsb = roundup_64(*last_fsb, align);
> error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
> if (error)
> return error;
> --
> 1.7.9.5
>
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