[PATCH 6/7] xfs: factor out stale buffer item completion

[Dave Chinner <david@fromorbit.com>]

From: Dave Chinner <dchinner@redhat.com>

The stale buffer item completion handling is currently only done
from BLI unpinning. We need to perform this function from where-ever
the last reference to the BLI is dropped, so first we need to
factor this code out into a helper.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf_item.c | 60 ++++++++++++++++++++++++++-----------------
 1 file changed, 37 insertions(+), 23 deletions(-)

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 3e3c0f65a25c..c95826863c82 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -444,6 +444,42 @@ xfs_buf_item_pin(
 	atomic_inc(&bip->bli_buf->b_pin_count);
 }
 
+/*
+ * For a stale BLI, process all the necessary completions that must be
+ * performed when the final BLI reference goes away. The buffer will be
+ * referenced and locked here - we return to the caller with the buffer still
+ * referenced and locked for them to finalise processing of the buffer.
+ */
+static void
+xfs_buf_item_finish_stale(
+	struct xfs_buf_log_item	*bip)
+{
+	struct xfs_buf		*bp = bip->bli_buf;
+	struct xfs_log_item	*lip = &bip->bli_item;
+
+	ASSERT(bip->bli_flags & XFS_BLI_STALE);
+	ASSERT(xfs_buf_islocked(bp));
+	ASSERT(bp->b_flags & XBF_STALE);
+	ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
+	ASSERT(list_empty(&lip->li_trans));
+	ASSERT(!bp->b_transp);
+
+	if (bip->bli_flags & XFS_BLI_STALE_INODE) {
+		xfs_buf_item_done(bp);
+		xfs_buf_inode_iodone(bp);
+		ASSERT(list_empty(&bp->b_li_list));
+		return;
+	}
+
+	/*
+	 * We may or may not be on the AIL here, xfs_trans_ail_delete() will do
+	 * the right thing regardless of the situation in which we are called.
+	 */
+	xfs_trans_ail_delete(lip, SHUTDOWN_LOG_IO_ERROR);
+	xfs_buf_item_relse(bip);
+	ASSERT(bp->b_log_item == NULL);
+}
+
 /*
  * This is called to unpin the buffer associated with the buf log item which was
  * previously pinned with a call to xfs_buf_item_pin().  We enter this function
@@ -493,13 +529,6 @@ xfs_buf_item_unpin(
 	}
 
 	if (stale) {
-		ASSERT(bip->bli_flags & XFS_BLI_STALE);
-		ASSERT(xfs_buf_islocked(bp));
-		ASSERT(bp->b_flags & XBF_STALE);
-		ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
-		ASSERT(list_empty(&lip->li_trans));
-		ASSERT(!bp->b_transp);
-
 		trace_xfs_buf_item_unpin_stale(bip);
 
 		/*
@@ -510,22 +539,7 @@ xfs_buf_item_unpin(
 		 * processing is complete.
 		 */
 		xfs_buf_rele(bp);
-
-		/*
-		 * If we get called here because of an IO error, we may or may
-		 * not have the item on the AIL. xfs_trans_ail_delete() will
-		 * take care of that situation. xfs_trans_ail_delete() drops
-		 * the AIL lock.
-		 */
-		if (bip->bli_flags & XFS_BLI_STALE_INODE) {
-			xfs_buf_item_done(bp);
-			xfs_buf_inode_iodone(bp);
-			ASSERT(list_empty(&bp->b_li_list));
-		} else {
-			xfs_trans_ail_delete(lip, SHUTDOWN_LOG_IO_ERROR);
-			xfs_buf_item_relse(bip);
-			ASSERT(bp->b_log_item == NULL);
-		}
+		xfs_buf_item_finish_stale(bip);
 		xfs_buf_relse(bp);
 		return;
 	}
-- 
2.45.2