Patch "xfs: streamline xfs_filestream_pick_ag" has been added to the 6.6-stable tree

This is a note to let you know that I've just added the patch titled

    xfs: streamline xfs_filestream_pick_ag

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xfs-streamline-xfs_filestream_pick_ag.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


From [email protected] Wed Feb  5 22:41:29 2025
From: Catherine Hoang <[email protected]>
Date: Wed,  5 Feb 2025 13:40:24 -0800
Subject: xfs: streamline xfs_filestream_pick_ag
To: [email protected]
Cc: [email protected]
Message-ID: <[email protected]>

From: Christoph Hellwig <[email protected]>

commit 81a1e1c32ef474c20ccb9f730afe1ac25b1c62a4 upstream.

Directly return the error from xfs_bmap_longest_free_extent instead
of breaking from the loop and handling it there, and use a done
label to directly jump to the exist when we found a suitable perag
structure to reduce the indentation level and pag/max_pag check
complexity in the tail of the function.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Carlos Maiolino <[email protected]>
Signed-off-by: Catherine Hoang <[email protected]>
Acked-by: Darrick J. Wong <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 fs/xfs/xfs_filestream.c |   96 +++++++++++++++++++++++-------------------------
 1 file changed, 46 insertions(+), 50 deletions(-)

--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -67,22 +67,28 @@ xfs_filestream_pick_ag(
 	xfs_extlen_t		minfree, maxfree = 0;
 	xfs_agnumber_t		agno;
 	bool			first_pass = true;
-	int			err;
 
 	/* 2% of an AG's blocks must be free for it to be chosen. */
 	minfree = mp->m_sb.sb_agblocks / 50;
 
 restart:
 	for_each_perag_wrap(mp, start_agno, agno, pag) {
+		int		err;
+
 		trace_xfs_filestream_scan(pag, pino);
+
 		*longest = 0;
 		err = xfs_bmap_longest_free_extent(pag, NULL, longest);
 		if (err) {
-			if (err != -EAGAIN)
-				break;
-			/* Couldn't lock the AGF, skip this AG. */
-			err = 0;
-			continue;
+			if (err == -EAGAIN) {
+				/* Couldn't lock the AGF, skip this AG. */
+				err = 0;
+				continue;
+			}
+			xfs_perag_rele(pag);
+			if (max_pag)
+				xfs_perag_rele(max_pag);
+			return err;
 		}
 
 		/* Keep track of the AG with the most free blocks. */
@@ -107,7 +113,9 @@ restart:
 			     !(flags & XFS_PICK_USERDATA) ||
 			     (flags & XFS_PICK_LOWSPACE))) {
 				/* Break out, retaining the reference on the AG. */
-				break;
+				if (max_pag)
+					xfs_perag_rele(max_pag);
+				goto done;
 			}
 		}
 
@@ -115,56 +123,44 @@ restart:
 		atomic_dec(&pag->pagf_fstrms);
 	}
 
-	if (err) {
-		xfs_perag_rele(pag);
-		if (max_pag)
-			xfs_perag_rele(max_pag);
-		return err;
+	/*
+	 * Allow a second pass to give xfs_bmap_longest_free_extent() another
+	 * attempt at locking AGFs that it might have skipped over before we
+	 * fail.
+	 */
+	if (first_pass) {
+		first_pass = false;
+		goto restart;
 	}
 
-	if (!pag) {
-		/*
-		 * Allow a second pass to give xfs_bmap_longest_free_extent()
-		 * another attempt at locking AGFs that it might have skipped
-		 * over before we fail.
-		 */
-		if (first_pass) {
-			first_pass = false;
-			goto restart;
-		}
-
-		/*
-		 * We must be low on data space, so run a final lowspace
-		 * optimised selection pass if we haven't already.
-		 */
-		if (!(flags & XFS_PICK_LOWSPACE)) {
-			flags |= XFS_PICK_LOWSPACE;
-			goto restart;
-		}
-
-		/*
-		 * No unassociated AGs are available, so select the AG with the
-		 * most free space, regardless of whether it's already in use by
-		 * another filestream. It none suit, just use whatever AG we can
-		 * grab.
-		 */
-		if (!max_pag) {
-			for_each_perag_wrap(args->mp, 0, start_agno, pag) {
-				max_pag = pag;
-				break;
-			}
+	/*
+	 * We must be low on data space, so run a final lowspace optimised
+	 * selection pass if we haven't already.
+	 */
+	if (!(flags & XFS_PICK_LOWSPACE)) {
+		flags |= XFS_PICK_LOWSPACE;
+		goto restart;
+	}
 
-			/* Bail if there are no AGs at all to select from. */
-			if (!max_pag)
-				return -ENOSPC;
+	/*
+	 * No unassociated AGs are available, so select the AG with the most
+	 * free space, regardless of whether it's already in use by another
+	 * filestream. It none suit, just use whatever AG we can grab.
+	 */
+	if (!max_pag) {
+		for_each_perag_wrap(args->mp, 0, start_agno, pag) {
+			max_pag = pag;
+			break;
 		}
 
-		pag = max_pag;
-		atomic_inc(&pag->pagf_fstrms);
-	} else if (max_pag) {
-		xfs_perag_rele(max_pag);
+		/* Bail if there are no AGs at all to select from. */
+		if (!max_pag)
+			return -ENOSPC;
 	}
 
+	pag = max_pag;
+	atomic_inc(&pag->pagf_fstrms);
+done:
 	trace_xfs_filestream_pick(pag, pino);
 	args->pag = pag;
 	return 0;


Patches currently in stable-queue which might be from [email protected] are

queue-6.6/xfs-return-bool-from-xfs_attr3_leaf_add.patch
queue-6.6/xfs-fix-a-sloppy-memory-handling-bug-in-xfs_iroot_realloc.patch
queue-6.6/xfs-streamline-xfs_filestream_pick_ag.patch
queue-6.6/xfs-merge-xfs_attr_leaf_try_add-into-xfs_attr_leaf_addname.patch
queue-6.6/xfs-don-t-free-cowblocks-from-under-dirty-pagecache-on-unshare.patch
queue-6.6/xfs-pass-the-exact-range-to-initialize-to-xfs_initialize_perag.patch
queue-6.6/xfs-assert-a-valid-limit-in-xfs_rtfind_forw.patch
queue-6.6/xfs-don-t-use-__gfp_retry_mayfail-in-xfs_initialize_perag.patch
queue-6.6/xfs-use-try_cmpxchg-in-xlog_cil_insert_pcp_aggregate.patch
queue-6.6/xfs-don-t-ifdef-around-the-exact-minlen-allocations.patch
queue-6.6/xfs-reduce-unnecessary-searches-when-searching-for-the-best-extents.patch
queue-6.6/xfs-validate-inumber-in-xfs_iget.patch
queue-6.6/xfs-support-lowmode-allocations-in-xfs_bmap_exact_minlen_extent_alloc.patch
queue-6.6/xfs-skip-background-cowblock-trims-on-inodes-open-for-write.patch
queue-6.6/xfs-remove-empty-declartion-in-header-file.patch
queue-6.6/xfs-fold-xfs_bmap_alloc_userdata-into-xfs_bmapi_allocate.patch
queue-6.6/xfs-update-the-file-system-geometry-after-recoverying-superblock-buffers.patch
queue-6.6/xfs-call-xfs_bmap_exact_minlen_extent_alloc-from-xfs_bmap_btalloc.patch
queue-6.6/xfs-distinguish-extra-split-from-real-enospc-from-xfs_attr_node_try_addname.patch
queue-6.6/xfs-error-out-when-a-superblock-buffer-update-reduces-the-agcount.patch
queue-6.6/xfs-update-the-pag-for-the-last-ag-at-recovery-time.patch
queue-6.6/xfs-check-for-delayed-allocations-before-setting-extsize.patch
queue-6.6/xfs-fix-a-typo.patch
queue-6.6/xfs-distinguish-extra-split-from-real-enospc-from-xfs_attr3_leaf_split.patch