Btrfs: fix race between balance recovery and root deletion (5f316481) · Commits · 戴 / test

Balance recovery is called when RW mounting or remounting from RO to RW, it is called to finish roots merging. When doing balance recovery, relocation root's corresponding fs root(whose root refs is 0) might be destroyed by cleaner thread, this will make btrfs fail to mount. Fix this problem by holding @cleaner_mutex when doing balance recovery. Signed-off-by:

Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/disk-io.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2905,7 +2905,9 @@ retry_root_backup:
		if (ret)
		goto fail_qgroup;

		mutex_lock(&fs_info->cleaner_mutex);
		ret = btrfs_recover_relocation(tree_root);
		mutex_unlock(&fs_info->cleaner_mutex);
		if (ret < 0) {
		printk(KERN_WARNING
		"BTRFS: failed to recover relocation\n");

fs/btrfs/super.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1467,7 +1467,9 @@ static int btrfs_remount(struct super_block sb, int flags, char *data)
		goto restore;

		/* recover relocation */
		mutex_lock(&fs_info->cleaner_mutex);
		ret = btrfs_recover_relocation(root);
		mutex_unlock(&fs_info->cleaner_mutex);
		if (ret)
		goto restore;

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