X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=fs%2Fxfs%2Fxfs_buf_item.c;h=becf4a97efc65c95240e45c1b05b751919d51317;hb=03b1293edad462ad1ad62bcc5160c76758e450d5;hp=a8d0ed911196120a80a26bb7232f79d3a5badee1;hpb=587a9e1f95794c05419d3bdb4c409a3274849f93;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index a8d0ed9..becf4a9 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -526,7 +526,25 @@ xfs_buf_item_unpin(
 		}
 		xfs_buf_relse(bp);
 	} else if (freed && remove) {
+		/*
+		 * There are currently two references to the buffer - the active
+		 * LRU reference and the buf log item. What we are about to do
+		 * here - simulate a failed IO completion - requires 3
+		 * references.
+		 *
+		 * The LRU reference is removed by the xfs_buf_stale() call. The
+		 * buf item reference is removed by the xfs_buf_iodone()
+		 * callback that is run by xfs_buf_do_callbacks() during ioend
+		 * processing (via the bp->b_iodone callback), and then finally
+		 * the ioend processing will drop the IO reference if the buffer
+		 * is marked XBF_ASYNC.
+		 *
+		 * Hence we need to take an additional reference here so that IO
+		 * completion processing doesn't free the buffer prematurely.
+		 */
 		xfs_buf_lock(bp);
+		xfs_buf_hold(bp);
+		bp->b_flags |= XBF_ASYNC;
 		xfs_buf_ioerror(bp, EIO);
 		XFS_BUF_UNDONE(bp);
 		xfs_buf_stale(bp);