linux-kernel - [PATCH 4.9 68/78] xfs: dont log dirty ranges for ordered buffers

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Date:   Mon, 18 Sep 2017 11:12:17 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Brian Foster <bfoster@...hat.com>,
        Allison Henderson <allison.henderson@...cle.com>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        Christoph Hellwig <hch@....de>
Subject: [PATCH 4.9 68/78] xfs: dont log dirty ranges for ordered buffers

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Brian Foster <bfoster@...hat.com>

commit 8dc518dfa7dbd079581269e51074b3c55a65a880 upstream.

Ordered buffers are attached to transactions and pushed through the
logging infrastructure just like normal buffers with the exception
that they are not actually written to the log. Therefore, we don't
need to log dirty ranges of ordered buffers. xfs_trans_log_buf() is
called on ordered buffers to set up all of the dirty state on the
transaction, buffer and log item and prepare the buffer for I/O.

Now that xfs_trans_dirty_buf() is available, call it from
xfs_trans_ordered_buf() so the latter is now mutually exclusive with
xfs_trans_log_buf(). This reflects the implementation of ordered
buffers and helps eliminate confusion over the need to log ranges of
ordered buffers just to set up internal log state.

Signed-off-by: Brian Foster <bfoster@...hat.com>
Reviewed-by: Allison Henderson <allison.henderson@...cle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@...cle.com>
Reviewed-by: Christoph Hellwig <hch@....de>
Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/xfs/libxfs/xfs_btree.c  |    6 ++----
 fs/xfs/libxfs/xfs_ialloc.c |    2 --
 fs/xfs/xfs_trans_buf.c     |   26 ++++++++++++++------------
 3 files changed, 16 insertions(+), 18 deletions(-)

--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -4447,12 +4447,10 @@ xfs_btree_block_change_owner(
 	 * though, so everything is consistent in memory.
 	 */
 	if (bp) {
-		if (cur->bc_tp) {
+		if (cur->bc_tp)
 			xfs_trans_ordered_buf(cur->bc_tp, bp);
-			xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
-		} else {
+		else
 			xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
-		}
 	} else {
 		ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
 		ASSERT(level == cur->bc_nlevels - 1);
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -368,8 +368,6 @@ xfs_ialloc_inode_init(
 				 * transaction and pin the log appropriately.
 				 */
 				xfs_trans_ordered_buf(tp, fbuf);
-				xfs_trans_log_buf(tp, fbuf, 0,
-						  BBTOB(fbuf->b_length) - 1);
 			}
 		} else {
 			fbuf->b_flags |= XBF_DONE;
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -560,16 +560,12 @@ xfs_trans_log_buf(
 	struct xfs_buf_log_item	*bip = bp->b_fspriv;
 
 	ASSERT(first <= last && last < BBTOB(bp->b_length));
+	ASSERT(!(bip->bli_flags & XFS_BLI_ORDERED));
 
 	xfs_trans_dirty_buf(tp, bp);
 
-	/*
-	 * If we have an ordered buffer we are not logging any dirty range but
-	 * it still needs to be marked dirty and that it has been logged.
-	 */
 	trace_xfs_trans_log_buf(bip);
-	if (!(bip->bli_flags & XFS_BLI_ORDERED))
-		xfs_buf_item_log(bip, first, last);
+	xfs_buf_item_log(bip, first, last);
 }
 
 
@@ -722,12 +718,11 @@ xfs_trans_inode_alloc_buf(
 }
 
 /*
- * Mark the buffer as ordered for this transaction. This means
- * that the contents of the buffer are not recorded in the transaction
- * but it is tracked in the AIL as though it was. This allows us
- * to record logical changes in transactions rather than the physical
- * changes we make to the buffer without changing writeback ordering
- * constraints of metadata buffers.
+ * Mark the buffer as ordered for this transaction. This means that the contents
+ * of the buffer are not recorded in the transaction but it is tracked in the
+ * AIL as though it was. This allows us to record logical changes in
+ * transactions rather than the physical changes we make to the buffer without
+ * changing writeback ordering constraints of metadata buffers.
  */
 void
 xfs_trans_ordered_buf(
@@ -739,9 +734,16 @@ xfs_trans_ordered_buf(
 	ASSERT(bp->b_transp == tp);
 	ASSERT(bip != NULL);
 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+	ASSERT(!xfs_buf_item_dirty_format(bip));
 
 	bip->bli_flags |= XFS_BLI_ORDERED;
 	trace_xfs_buf_item_ordered(bip);
+
+	/*
+	 * We don't log a dirty range of an ordered buffer but it still needs
+	 * to be marked dirty and that it has been logged.
+	 */
+	xfs_trans_dirty_buf(tp, bp);
 }
 
 /*