Re: [PATCH OLK-5.10 3/9] xfs: align args->minlen for forced allocation alignment

LGTM

在 2024/8/8 21:32, Long Li 写道:

From: Dave Chinner dchinner@redhat.com

maillist inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9VTE3 CVE: NA

Reference: https://lore.kernel.org/linux-xfs/20240705162450.3481169-1-john.g.garry@orac...

---

If args->minlen is not aligned to the constraints of forced alignment, we may do minlen allocations that are not aligned when we approach ENOSPC. Avoid this by always aligning args->minlen appropriately. If alignment of minlen results in a value smaller than the alignment constraint, fail the allocation immediately.

Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: "Darrick J. Wong" djwong@kernel.org Signed-off-by: John Garry john.g.garry@oracle.com Conflicts: fs/xfs/libxfs/xfs_bmap.c [Conflicts in xfs_bmap_select_minlen()] Signed-off-by: Long Li leo.lilong@huawei.com

---

fs/xfs/libxfs/xfs_bmap.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 7682dfe2f701..284cc73b8bef 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -3253,32 +3253,47 @@ xfs_bmap_longest_free_extent( return error; }

-static void +static int xfs_bmap_select_minlen( struct xfs_bmalloca *ap, struct xfs_alloc_arg *args, xfs_extlen_t *blen, int notinit) {

• xfs_extlen_t nlen = 0;
• if (notinit || *blen < ap->minlen) { /*
  • Since we did a BUF_TRYLOCK above, it is possible that
  • there is space for this request.
  */

• args->minlen = ap->minlen;
  

• nlen = ap->minlen;
  

  } else if (*blen < args->maxlen) { /*
  • If the best seen length is less than the request length,
  • use the best as the minimum.
  */

• args->minlen = *blen;
  

• nlen = *blen;
  

  } else { /*
  • Otherwise we've seen an extent as big as maxlen, use that
  • as the minimum.
  */

• args->minlen = args->maxlen;
  

• nlen = args->maxlen;
  

  }

• if (args->alignment > 1) {

• nlen = rounddown(nlen, args->alignment);
  

• if (nlen < ap->minlen) {
  

• 	if (xfs_inode_forcealign(ap->ip) &&
  

• 		(ap->datatype & XFS_ALLOC_USERDATA))
  

• 		return -ENOSPC;
  

• 	nlen = ap->minlen;
  

• }
  

• }

• args->minlen = nlen;

• return 0; }

  STATIC int

@@ -3311,8 +3326,8 @@ xfs_bmap_btalloc_nullfb( break; }

• xfs_bmap_select_minlen(ap, args, blen, notinit);
• return 0;

• error = xfs_bmap_select_minlen(ap, args, blen, notinit);

• return error; }

  STATIC int

@@ -3349,7 +3364,9 @@ xfs_bmap_btalloc_filestreams(

}

• xfs_bmap_select_minlen(ap, args, blen, notinit);

• error = xfs_bmap_select_minlen(ap, args, blen, notinit);

• if (error)

• return error;
  
  

  /*

  • Set the failure fallback case to look in the selected AG as stream