Re: [PATCH v2] xfs: introduce xfs_validate_stripe_geometry()

Brian Foster
2020-10-13T13:44:29Z

On Tue, Oct 13, 2020 at 11:48:53AM +0800, Gao Xiang wrote:
> Introduce a common helper to consolidate stripe validation process.
> Also make kernel code xfs_validate_sb_common() use it first.
>
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
> v1: https://lore.kernel.org/r/20201009050546.32174-1-hsiangkao@redhat.com
>
> changes since v1:
> - rename the helper to xfs_validate_stripe_geometry() (Brian);
> - drop a new added trailing newline in xfs_sb.c (Brian);
> - add a "bool silent" argument to avoid too many error messages (Brian).
>
> fs/xfs/libxfs/xfs_sb.c | 70 +++++++++++++++++++++++++++++++++++-------
> fs/xfs/libxfs/xfs_sb.h | 3 ++
> 2 files changed, 62 insertions(+), 11 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index 5aeafa59ed27..9178715ded45 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -360,21 +360,18 @@ xfs_validate_sb_common(
> }
> }
>
> - if (sbp->sb_unit) {
> - if (!xfs_sb_version_hasdalign(sbp) ||
> - sbp->sb_unit > sbp->sb_width ||
> - (sbp->sb_width % sbp->sb_unit) != 0) {
> - xfs_notice(mp, "SB stripe unit sanity check failed");
> - return -EFSCORRUPTED;
> - }
> - } else if (xfs_sb_version_hasdalign(sbp)) {
> + /*
> + * Either (sb_unit and !hasdalign) or (!sb_unit and hasdalign)
> + * would imply the image is corrupted.
> + */
> + if (!sbp->sb_unit ^ !xfs_sb_version_hasdalign(sbp)) {

This can be simplified to drop the negations (!), right?

> xfs_notice(mp, "SB stripe alignment sanity check failed");
> return -EFSCORRUPTED;
> - } else if (sbp->sb_width) {
> - xfs_notice(mp, "SB stripe width sanity check failed");
> - return -EFSCORRUPTED;
> }
>
> + if (!xfs_validate_stripe_geometry(mp, XFS_FSB_TO_B(mp, sbp->sb_unit),
> + XFS_FSB_TO_B(mp, sbp->sb_width), 0, false))
> + return -EFSCORRUPTED;
>
> if (xfs_sb_version_hascrc(&mp->m_sb) &&
> sbp->sb_blocksize < XFS_MIN_CRC_BLOCKSIZE) {
> @@ -1233,3 +1230,54 @@ xfs_sb_get_secondary(
> *bpp = bp;
> return 0;
> }
> +
> +/*
> + * sunit, swidth, sectorsize(optional with 0) should be all in bytes,
> + * so users won't be confused by values in error messages.
> + */
> +bool
> +xfs_validate_stripe_geometry(
> + struct xfs_mount *mp,
> + __s64 sunit,
> + __s64 swidth,
> + int sectorsize,
> + bool silent)
> +{
> + if (sectorsize && sunit % sectorsize) {
> + if (!silent)
> + xfs_notice(mp,
> +"stripe unit (%lld) must be a multiple of the sector size (%d)",
> + sunit, sectorsize);
> + return false;
> + }
> +
> + if (sunit && !swidth) {
> + if (!silent)
> + xfs_notice(mp,
> +"invalid stripe unit (%lld) and stripe width of 0", sunit);
> + return false;
> + }
> +
> + if (!sunit && swidth) {
> + if (!silent)
> + xfs_notice(mp,
> +"invalid stripe width (%lld) and stripe unit of 0", swidth);
> + return false;
> + }
> +
> + if (sunit > swidth) {
> + if (!silent)
> + xfs_notice(mp,
> +"stripe unit (%lld) is larger than the stripe width (%lld)", sunit, swidth);
> + return false;
> + }
> +
> + if (sunit && (swidth % sunit)) {

It might be good to use (or not) params consistently. I.e., the
sectorsize check earlier in the function has similar logic structure but
drops the params.

Those nits aside:

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

> + if (!silent)
> + xfs_notice(mp,
> +"stripe width (%lld) must be a multiple of the stripe unit (%lld)",
> + swidth, sunit);
> + return false;
> + }
> + return true;
> +}
> diff --git a/fs/xfs/libxfs/xfs_sb.h b/fs/xfs/libxfs/xfs_sb.h
> index 92465a9a5162..f79f9dc632b6 100644
> --- a/fs/xfs/libxfs/xfs_sb.h
> +++ b/fs/xfs/libxfs/xfs_sb.h
> @@ -42,4 +42,7 @@ extern int xfs_sb_get_secondary(struct xfs_mount *mp,
> struct xfs_trans *tp, xfs_agnumber_t agno,
> struct xfs_buf **bpp);
>
> +extern bool xfs_validate_stripe_geometry(struct xfs_mount *mp,
> + __s64 sunit, __s64 swidth, int sectorsize, bool silent);
> +
> #endif /* __XFS_SB_H__ */
> --
> 2.18.1
>