On 2022/11/30 6:01, Darrick J. Wong wrote:
From: Darrick J. Wong<djwong@xxxxxxxxxx>
Upon enabling fsdax + reflink for XFS, xfs/179 began to report refcount
metadata corruptions after being run. Specifically, xfs_repair noticed
single-block refcount records that could be combined but had not been.
Hi Darrick,
I am investigating the issue as well. Thanks a lot for your quick fix.
I have confirmed that xfs/179 with the fix patch can works well in DAX mode.
Reviewed-by: Xiao Yang <yangx.jy@xxxxxxxxxxx>
The root cause of this is improper MAXREFCOUNT edge case handling in
xfs_refcount_merge_extents. When we're trying to find candidates for a
refcount btree record merge, we compute the refcount attribute of the
merged record, but we fail to account for the fact that once a record
hits rc_refcount == MAXREFCOUNT, it is pinned that way forever. Hence
One question:
Is it reansonable/expected to pin rc_refcount forever when a record hits
rc_refcount == MAXREFCOUNT?
the computed refcount is wrong, and we fail to merge the extents.
Fix this by adjusting the merge predicates to compute the adjusted
refcount correctly.
Best Regards,
Xiao Yang
