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From: Allison Henderson <allison.henderson@oracle.com>
To: linux-xfs@vger.kernel.org
Subject: [PATCH v2 05/18] xfsprogs: Fix double unlock in defer capture code
Date: Fri, 20 May 2022 12:00:18 -0700	[thread overview]
Message-ID: <20220520190031.2198236-6-allison.henderson@oracle.com> (raw)
In-Reply-To: <20220520190031.2198236-1-allison.henderson@oracle.com>

Source kernel commit: 7b3ec2b20e44f579c022ad62243aa18c04c6addc

The new deferred attr patch set uncovered a double unlock in the
recent port of the defer ops capture and continue code.  During log
recovery, we're allowed to hold buffers to a transaction that's being
used to replay an intent item.  When we capture the resources as part
of scheduling a continuation of an intent chain, we call xfs_buf_hold
to retain our reference to the buffer beyond the transaction commit,
but we do /not/ call xfs_trans_bhold to maintain the buffer lock.
This means that xfs_defer_ops_continue needs to relock the buffers
before xfs_defer_restore_resources joins then tothe new transaction.

Additionally, the buffers should not be passed back via the dres
structure since they need to remain locked unlike the inodes.  So
simply set dr_bufs to zero after populating the dres structure.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
---
 libxfs/xfs_defer.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/libxfs/xfs_defer.c b/libxfs/xfs_defer.c
index d654a7d9af82..3a2576c14ee9 100644
--- a/libxfs/xfs_defer.c
+++ b/libxfs/xfs_defer.c
@@ -776,17 +776,25 @@ xfs_defer_ops_continue(
 	struct xfs_trans		*tp,
 	struct xfs_defer_resources	*dres)
 {
+	unsigned int			i;
+
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 	ASSERT(!(tp->t_flags & XFS_TRANS_DIRTY));
 
-	/* Lock and join the captured inode to the new transaction. */
+	/* Lock the captured resources to the new transaction. */
 	if (dfc->dfc_held.dr_inos == 2)
 		xfs_lock_two_inodes(dfc->dfc_held.dr_ip[0], XFS_ILOCK_EXCL,
 				    dfc->dfc_held.dr_ip[1], XFS_ILOCK_EXCL);
 	else if (dfc->dfc_held.dr_inos == 1)
 		xfs_ilock(dfc->dfc_held.dr_ip[0], XFS_ILOCK_EXCL);
+
+	for (i = 0; i < dfc->dfc_held.dr_bufs; i++)
+		pthread_mutex_lock(&dfc->dfc_held.dr_bp[i]->b_lock);
+
+	/* Join the captured resources to the new transaction. */
 	xfs_defer_restore_resources(tp, &dfc->dfc_held);
 	memcpy(dres, &dfc->dfc_held, sizeof(struct xfs_defer_resources));
+	dres->dr_bufs = 0;
 
 	/* Move captured dfops chain and state to the transaction. */
 	list_splice_init(&dfc->dfc_dfops, &tp->t_dfops);
-- 
2.25.1


  parent reply	other threads:[~2022-05-20 19:00 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-20 19:00 [PATCH v2 00/18] xfsprogs: Port larp, enable injects and log print for attri/d Allison Henderson
2022-05-20 19:00 ` [PATCH v2 01/18] xfsprogs: zero inode fork buffer at allocation Allison Henderson
2022-05-20 19:00 ` [PATCH v2 02/18] xfsprogs: hide log iovec alignment constraints Allison Henderson
2022-05-20 19:00 ` [PATCH v2 03/18] xfsprogs: don't commit the first deferred transaction without intents Allison Henderson
2022-05-20 19:00 ` [PATCH v2 04/18] xfsprogs: tag transactions that contain intent done items Allison Henderson
2022-05-20 19:00 ` Allison Henderson [this message]
2022-05-20 19:00 ` [PATCH v2 06/18] xfsprogs: Return from xfs_attr_set_iter if there are no more rmtblks to process Allison Henderson
2022-05-20 19:00 ` [PATCH v2 07/18] xfsprogs: Set up infrastructure for log attribute replay Allison Henderson
2022-05-20 19:00 ` [PATCH v2 08/18] xfsprogs: Implement attr logging and replay Allison Henderson
2022-05-20 19:00 ` [PATCH v2 09/18] xfsprogs: Skip flip flags for delayed attrs Allison Henderson
2022-05-20 19:00 ` [PATCH v2 10/18] xfsprogs: Add xfs_attr_set_deferred and xfs_attr_remove_deferred Allison Henderson
2022-05-20 19:00 ` [PATCH v2 11/18] xfsprogs: Remove unused xfs_attr_*_args Allison Henderson
2022-05-20 19:00 ` [PATCH v2 12/18] xfsprogs: Add log attribute error tag Allison Henderson
2022-05-20 19:00 ` [PATCH v2 13/18] xfsprogs: Merge xfs_delattr_context into xfs_attr_item Allison Henderson
2022-05-20 19:00 ` [PATCH v2 14/18] xfsprogs: Add helper function xfs_attr_leaf_addname Allison Henderson
2022-05-20 19:00 ` [PATCH v2 15/18] xfsprogs: Add helper function xfs_init_attr_trans Allison Henderson
2022-05-20 19:00 ` [PATCH v2 16/18] xfsprogs: add leaf split error tag Allison Henderson
2022-05-20 19:00 ` [PATCH v2 17/18] xfsprogs: add leaf to node " Allison Henderson
2022-05-20 19:00 ` [PATCH v2 18/18] xfs_logprint: Add log item printing for ATTRI and ATTRD Allison Henderson
2022-05-31  6:03   ` Dave Chinner
2022-06-01  1:39     ` Alli

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