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[2/6] xfs: set XBF_DONE on newly formatted btree block that are ready for writing

Message ID 170191665178.1180191.7709444254217822674.stgit@frogsfrogsfrogs (mailing list archive)
State Superseded
Headers show
Series xfs: prepare repair for bulk loading | expand

Commit Message

Darrick J. Wong Dec. 7, 2023, 2:38 a.m. UTC 
From: Darrick J. Wong <djwong@kernel.org>

The btree bulkloading code calls xfs_buf_delwri_queue_here when it has
finished formatting a new btree block and wants to queue it to be
written to disk.  Once the new btree root has been committed, the blocks
(and hence the buffers) will be accessible to the rest of the
filesystem.  Mark each new buffer as DONE when adding it to the delwri
list so that the next btree traversal can skip reloading the contents
from disk.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_buf.c |    8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Christoph Hellwig Dec. 7, 2023, 5:26 a.m. UTC | #1 
On Wed, Dec 06, 2023 at 06:38:50PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> The btree bulkloading code calls xfs_buf_delwri_queue_here when it has
> finished formatting a new btree block and wants to queue it to be
> written to disk.  Once the new btree root has been committed, the blocks
> (and hence the buffers) will be accessible to the rest of the
> filesystem.  Mark each new buffer as DONE when adding it to the delwri
> list so that the next btree traversal can skip reloading the contents
> from disk.

This still seems like the wrong place to me - it really is the caller
that fills it out that should set the DONE flag, not a non-standard
delwri helper that should hopefully go away in the future.
Darrick J. Wong Dec. 11, 2023, 6:55 p.m. UTC | #2 
On Wed, Dec 06, 2023 at 09:26:06PM -0800, Christoph Hellwig wrote:
> On Wed, Dec 06, 2023 at 06:38:50PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > The btree bulkloading code calls xfs_buf_delwri_queue_here when it has
> > finished formatting a new btree block and wants to queue it to be
> > written to disk.  Once the new btree root has been committed, the blocks
> > (and hence the buffers) will be accessible to the rest of the
> > filesystem.  Mark each new buffer as DONE when adding it to the delwri
> > list so that the next btree traversal can skip reloading the contents
> > from disk.
> 
> This still seems like the wrong place to me - it really is the caller
> that fills it out that should set the DONE flag, not a non-standard
> delwri helper that should hopefully go away in the future.

I'll move it to xfs_btree_bload_drop_buf then.

--D
diff mbox series

Patch

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index ec4bd7a24d88c..702b3a1f9d1c4 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -2152,6 +2152,14 @@  xfs_buf_delwri_queue_here(
 
 	ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
 
+	/*
+	 * The buffer is locked.  The _delwri_queue below will bhold the buffer
+	 * so it cannot be reclaimed until the blocks are written to disk.
+	 * Mark this buffer XBF_DONE (i.e. uptodate) so that a subsequent
+	 * xfs_buf_read will not pointlessly reread the contents from the disk.
+	 */
+	bp->b_flags |= XBF_DONE;
+
 	xfs_buf_delwri_queue(bp, buffer_list);
 }