From: Filipe Manana <fdmanana@suse.com>
Date: Tue, 3 Feb 2026 19:45:14 +0000 (+0000)
Subject: btrfs: remove max_mirrors argument from write_all_supers()
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8f3fc2d8973af8dc5559ecbbfb5ed3b19b2e8fa5;p=thirdparty%2Flinux.git

btrfs: remove max_mirrors argument from write_all_supers()

There's no need to pass max_mirrors to write_all_supers() since from the
given transaction handle we can infer if we are in a transaction commit
or fsync context, so we can determine how many mirrors we need to use.

So remove the max_mirror argument from write_all_supers() and stop
adjusting it in the callees write_dev_supers() and wait_dev_supers(),
simplifying them besides the parameter list for write_all_supers().

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 89f5423f0366..e4a2673ffeaa 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3756,8 +3756,7 @@ static void btrfs_end_super_write(struct bio *bio)
  * Write superblock @sb to the @device. Do not wait for completion, all the
  * folios we use for writing are locked.
  *
- * Write @max_mirrors copies of the superblock, where 0 means default that fit
- * the expected device size at commit time. Note that max_mirrors must be
+ * Write @max_mirrors copies of the superblock. Note that max_mirrors must be
  * same for write and wait phases.
  *
  * Return number of errors when folio is not found or submission fails.
@@ -3773,9 +3772,6 @@ static int write_dev_supers(struct btrfs_device *device,
 
 	atomic_set(&device->sb_write_errors, 0);
 
-	if (max_mirrors == 0)
-		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
-
 	for (i = 0; i < max_mirrors; i++) {
 		struct folio *folio;
 		struct bio *bio;
@@ -3860,9 +3856,6 @@ static int wait_dev_supers(struct btrfs_device *device, int max_mirrors)
 	int ret;
 	u64 bytenr;
 
-	if (max_mirrors == 0)
-		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
-
 	for (i = 0; i < max_mirrors; i++) {
 		struct folio *folio;
 
@@ -4032,13 +4025,14 @@ int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags)
 	return min_tolerated;
 }
 
-int write_all_supers(struct btrfs_trans_handle *trans, int max_mirrors)
+int write_all_supers(struct btrfs_trans_handle *trans)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct list_head *head;
 	struct btrfs_device *dev;
 	struct btrfs_super_block *sb;
 	struct btrfs_dev_item *dev_item;
+	int max_mirrors;
 	int ret;
 	int do_barriers;
 	int max_errors;
@@ -4047,12 +4041,12 @@ int write_all_supers(struct btrfs_trans_handle *trans, int max_mirrors)
 
 	do_barriers = !btrfs_test_opt(fs_info, NOBARRIER);
 
-	/*
-	 * max_mirrors == 0 indicates we're from commit_transaction,
-	 * not from fsync where the tree roots in fs_info have not
-	 * been consistent on disk.
-	 */
-	if (max_mirrors == 0) {
+	if (trans->transaction->state < TRANS_STATE_UNBLOCKED) {
+		/* We are called from fsync. */
+		max_mirrors = 1;
+	} else {
+		/* We are called from transaction commit. */
+		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
 		ret = backup_super_roots(fs_info);
 		if (ret < 0)
 			return ret;
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 081a6860861c..163f5114973a 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -58,7 +58,7 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info);
 int btrfs_validate_super(const struct btrfs_fs_info *fs_info,
 			 const struct btrfs_super_block *sb, int mirror_num);
 int btrfs_check_features(struct btrfs_fs_info *fs_info, bool is_rw_mount);
-int write_all_supers(struct btrfs_trans_handle *trans, int max_mirrors);
+int write_all_supers(struct btrfs_trans_handle *trans);
 int btrfs_commit_super(struct btrfs_fs_info *fs_info);
 struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
 					const struct btrfs_key *key);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 8f24a025625e..4c1fcf9a71a2 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -2573,7 +2573,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 		goto scrub_continue;
 	}
 
-	ret = write_all_supers(trans, 0);
+	ret = write_all_supers(trans);
 	/*
 	 * the super is written, we can safely allow the tree-loggers
 	 * to go about their business
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 4f360ccf8380..304a4325e2e0 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3576,7 +3576,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 
 	btrfs_set_super_log_root(fs_info->super_for_commit, log_root_start);
 	btrfs_set_super_log_root_level(fs_info->super_for_commit, log_root_level);
-	ret = write_all_supers(trans, 1);
+	ret = write_all_supers(trans);
 	mutex_unlock(&fs_info->tree_log_mutex);
 	if (unlikely(ret)) {
 		btrfs_set_log_full_commit(trans);