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-rw-r--r--fs/xfs/xfs_buf_item.c18
1 files changed, 18 insertions, 0 deletions
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);
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