[02/22] xfs: fix inode quota reservation checks
diff mbox series

Message ID 159398716693.425236.15439173124100012153.stgit@magnolia
State Superseded
Headers show
  • xfs: remove xfs_disk_quot from incore dquot
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Commit Message

Darrick J. Wong July 5, 2020, 10:12 p.m. UTC
From: Darrick J. Wong <darrick.wong@oracle.com>

xfs_trans_dqresv is the function that we use to make reservations
against resource quotas.  Each resource contains two counters: the
q_core counter, which tracks resources allocated on disk; and the dquot
reservation counter, which tracks how much of that resource has either
been allocated or reserved by threads that are working on metadata

For disk blocks, we compare the proposed reservation counter against the
hard and soft limits to decide if we're going to fail the operation.
However, for inodes we inexplicably compare against the q_core counter,
not the incore reservation count.

Since the q_core counter is always lower than the reservation count and
we unlock the dquot between reservation and transaction commit, this
means that multiple threads can reserve the last inode count before we
hit the hard limit, and when they commit, we'll be well over the hard

Fix this by checking against the incore inode reservation counter, since
we would appear to maintain that correctly (and that's what we report in

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
 fs/xfs/xfs_trans_dquot.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff mbox series

diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
index c0f73b82c055..ed0ce8b301b4 100644
--- a/fs/xfs/xfs_trans_dquot.c
+++ b/fs/xfs/xfs_trans_dquot.c
@@ -647,7 +647,7 @@  xfs_trans_dqresv(
 		if (ninos > 0) {
-			total_count = be64_to_cpu(dqp->q_core.d_icount) + ninos;
+			total_count = dqp->q_res_icount + ninos;
 			timer = be32_to_cpu(dqp->q_core.d_itimer);
 			warns = be16_to_cpu(dqp->q_core.d_iwarns);
 			warnlimit = defq->iwarnlimit;