From: Darrick J. Wong <djwong@xxxxxxxxxx>
Source kernel commit: 3a3a253f66c5d3ab2712a9d4794b457195a503d7
Prior to calling xfs_refcount_adjust_extents, we trimmed agbno/aglen
such that the end of the range would not be in the middle of a refcount
record. If this is no longer the case, something is seriously wrong
with the btree. Bail out with a corruption error.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
libxfs/xfs_refcount.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/libxfs/xfs_refcount.c b/libxfs/xfs_refcount.c
index bcd760fe12..146e833b0d 100644
--- a/libxfs/xfs_refcount.c
+++ b/libxfs/xfs_refcount.c
@@ -985,15 +985,29 @@ xfs_refcount_adjust_extents(
(*agbno) += tmp.rc_blockcount;
(*aglen) -= tmp.rc_blockcount;
+ /* Stop if there's nothing left to modify */
+ if (*aglen == 0 || !xfs_refcount_still_have_space(cur))
+ break;
+
+ /* Move the cursor to the start of ext. */
error = xfs_refcount_lookup_ge(cur, *agbno,
&found_rec);
if (error)
goto out_error;
}
- /* Stop if there's nothing left to modify */
- if (*aglen == 0 || !xfs_refcount_still_have_space(cur))
- break;
+ /*
+ * A previous step trimmed agbno/aglen such that the end of the
+ * range would not be in the middle of the record. If this is
+ * no longer the case, something is seriously wrong with the
+ * btree. Make sure we never feed the synthesized record into
+ * the processing loop below.
+ */
+ if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount == 0) ||
+ XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount > *aglen)) {
+ error = -EFSCORRUPTED;
+ goto out_error;
+ }
/*
* Adjust the reference count and either update the tree
