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authorWang Shilong <wangsl.fnst@cn.fujitsu.com>2014-06-26 11:08:16 +0800
committerChris Mason <clm@fb.com>2014-07-03 07:04:04 -0700
commit5f3164813b90f7dbcb5c3ab9006906222ce471b7 (patch)
treeb176f089dda953a935d4987c6d02ea3783cb56d7
parent3cc79392558f1789e5e1d2fce44b681980f403c3 (diff)
Btrfs: fix race between balance recovery and root deletion
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>
-rw-r--r--fs/btrfs/disk-io.c2
-rw-r--r--fs/btrfs/super.c2
2 files changed, 4 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f00165de6fb..08e65e9cf2a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -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");
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 4662d92a4b7..b6ebde231de 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -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;