From: Darrick J. Wong Date: Mon, 9 Nov 2020 00:32:42 +0000 (-0800) Subject: xfs: fix brainos in the refcount scrubber's rmap fragment processor X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=54e9b09e153842ab5adb8a460b891e11b39e9c3d;p=linux.git xfs: fix brainos in the refcount scrubber's rmap fragment processor Fix some serious WTF in the reference count scrubber's rmap fragment processing. The code comment says that this loop is supposed to move all fragment records starting at or before bno onto the worklist, but there's no obvious reason why nr (the number of items added) should increment starting from 1, and breaking the loop when we've added the target number seems dubious since we could have more rmap fragments that should have been added to the worklist. This seems to manifest in xfs/411 when adding one to the refcount field. Fixes: dbde19da9637 ("xfs: cross-reference the rmapbt data with the refcountbt") Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- diff --git a/fs/xfs/scrub/refcount.c b/fs/xfs/scrub/refcount.c index beaeb6fa31197..dd672e6bbc75c 100644 --- a/fs/xfs/scrub/refcount.c +++ b/fs/xfs/scrub/refcount.c @@ -170,7 +170,6 @@ xchk_refcountbt_process_rmap_fragments( */ INIT_LIST_HEAD(&worklist); rbno = NULLAGBLOCK; - nr = 1; /* Make sure the fragments actually /are/ in agbno order. */ bno = 0; @@ -184,15 +183,14 @@ xchk_refcountbt_process_rmap_fragments( * Find all the rmaps that start at or before the refc extent, * and put them on the worklist. */ + nr = 0; list_for_each_entry_safe(frag, n, &refchk->fragments, list) { - if (frag->rm.rm_startblock > refchk->bno) - goto done; + if (frag->rm.rm_startblock > refchk->bno || nr > target_nr) + break; bno = frag->rm.rm_startblock + frag->rm.rm_blockcount; if (bno < rbno) rbno = bno; list_move_tail(&frag->list, &worklist); - if (nr == target_nr) - break; nr++; }