[PATCH 1/2] libxfs: clear the buffer error while the buffer is locked

[Dave Chinner]

From: Dave Chinner <dchinner at redhat.com>

When releasing a buffer, the error shoul dbe cleared while the lock
is still held on the buffer to avoid racing with a new user of the
buffer.

This was pointed out in review of commit 6af7c1e ("libxfs: reused
invalidated buffers leak state and data") but the version committed
didn't have the fix. Thanks to Christoph Hellwig for checking and
pointing out the oversight.

Reported-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Dave Chinner <dchinner at redhat.com>
---
 libxfs/rdwr.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/libxfs/rdwr.c b/libxfs/rdwr.c
index 0294c98..9ee89d3 100644
--- a/libxfs/rdwr.c
+++ b/libxfs/rdwr.c
@@ -648,6 +648,12 @@ libxfs_getbuf_map(struct xfs_buftarg *btp, struct xfs_buf_map *map,
 void
 libxfs_putbuf(xfs_buf_t *bp)
 {
+	/*
+	 * ensure that any errors on this use of the buffer don't carry
+	 * over to the next user.
+	 */
+	bp->b_error = 0;
+
 #ifdef XFS_BUF_TRACING
 	pthread_mutex_lock(&libxfs_bcache->c_mutex);
 	lock_buf_count--;
@@ -663,11 +669,6 @@ libxfs_putbuf(xfs_buf_t *bp)
 			pthread_mutex_unlock(&bp->b_lock);
 		}
 	}
-	/*
-	 * ensure that any errors on this use of the buffer don't carry
-	 * over to the next user.
-	 */
-	bp->b_error = 0;
 
 	cache_node_put(libxfs_bcache, (struct cache_node *)bp);
 }
-- 
2.0.0