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

Commit Message

Darrick J. Wong Dec. 13, 2023, 10:52 p.m. UTC

From: Darrick J. Wong <[e-mail]>

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 <[e-mail]>
---
 fs/xfs/libxfs/xfs_btree_staging.c |    6 ++++++
 1 file changed, 6 insertions(+)

Comments

Christoph Hellwig Dec. 14, 2023, 4:45 a.m. UTC | #1

On Wed, Dec 13, 2023 at 02:52:13PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <[e-mail]>
> 
> 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.

Looks good:

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/fs/xfs/libxfs/xfs_btree_staging.c b/fs/xfs/libxfs/xfs_btree_staging.c
index 29e3f8ccb185..1c5f9ed70c3e 100644
--- a/fs/xfs/libxfs/xfs_btree_staging.c
+++ b/fs/xfs/libxfs/xfs_btree_staging.c
@@ -342,6 +342,12 @@  xfs_btree_bload_drop_buf(
 	if (*bpp == NULL)
 		return;
 
+	/*
+	 * Mark this buffer XBF_DONE (i.e. uptodate) so that a subsequent
+	 * xfs_buf_read will not pointlessly reread the contents from the disk.
+	 */
+	(*bpp)->b_flags |= XBF_DONE;
+
 	xfs_buf_delwri_queue_here(*bpp, buffers_list);
 	xfs_buf_relse(*bpp);
 	*bpp = NULL;