Btrfs: restore restriper state on all mounts

Fix a bug that triggered asserts in btrfs_balance() in both normal and
resume modes -- restriper state was not properly restored on read-only
mounts.  This factors out resuming code from btrfs_restore_balance(),
which is now also called earlier in the mount sequence to avoid the
problem of some early writes getting the old profile.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

3 files changed, 26 insertions, 25 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7d7bc8eace86..3a7961ba161e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2354,12 +2354,17 @@ retry_root_backup:
                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
         if (ret)
                 goto recovery_tree_root;
-
         csum_root->track_dirty = 1;
 
         fs_info->generation = generation;
         fs_info->last_trans_committed = generation;
 
+        ret = btrfs_recover_balance(fs_info);
+        if (ret) {
+                printk(KERN_WARNING "btrfs: failed to recover balance\n");
+                goto fail_block_groups;
+        }
+
         ret = btrfs_init_dev_stats(fs_info);
         if (ret) {
                 printk(KERN_ERR "btrfs: failed to init dev_stats: %d\n",
@@ -2492,9 +2497,6 @@ retry_root_backup:
                         err = btrfs_orphan_cleanup(fs_info->tree_root);
                 up_read(&fs_info->cleanup_work_sem);
 
-                if (!err)
-                        err = btrfs_recover_balance(fs_info->tree_root);
-
                 if (err) {
                         close_ctree(tree_root);
                         return err;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3f292cf693a7..48943d0f861a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2867,9 +2867,8 @@ static int balance_kthread(void *data)
         return ret;
 }
 
-int btrfs_recover_balance(struct btrfs_root *tree_root)
+int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
 {
-        struct task_struct *tsk;
         struct btrfs_balance_control *bctl;
         struct btrfs_balance_item *item;
         struct btrfs_disk_balance_args disk_bargs;
@@ -2882,29 +2881,30 @@ int btrfs_recover_balance(struct btrfs_root *tree_root)
         if (!path)
                 return -ENOMEM;
 
-        bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
-        if (!bctl) {
-                ret = -ENOMEM;
-                goto out;
-        }
-
         key.objectid = BTRFS_BALANCE_OBJECTID;
         key.type = BTRFS_BALANCE_ITEM_KEY;
         key.offset = 0;
 
-        ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+        ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
         if (ret < 0)
-                goto out_bctl;
+                goto out;
         if (ret > 0) { /* ret = -ENOENT; */
                 ret = 0;
-                goto out_bctl;
+                goto out;
+        }
+
+        bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
+        if (!bctl) {
+                ret = -ENOMEM;
+                goto out;
         }
 
         leaf = path->nodes[0];
         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
 
-        bctl->fs_info = tree_root->fs_info;
-        bctl->flags = btrfs_balance_flags(leaf, item) | BTRFS_BALANCE_RESUME;
+        bctl->fs_info = fs_info;
+        bctl->flags = btrfs_balance_flags(leaf, item);
+        bctl->flags |= BTRFS_BALANCE_RESUME;
 
         btrfs_balance_data(leaf, item, &disk_bargs);
         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
@@ -2913,14 +2913,13 @@ int btrfs_recover_balance(struct btrfs_root *tree_root)
         btrfs_balance_sys(leaf, item, &disk_bargs);
         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
 
-        tsk = kthread_run(balance_kthread, bctl, "btrfs-balance");
-        if (IS_ERR(tsk))
-                ret = PTR_ERR(tsk);
-        else
-                goto out;
+        mutex_lock(&fs_info->volume_mutex);
+        mutex_lock(&fs_info->balance_mutex);
 
-out_bctl:
-        kfree(bctl);
+        set_balance_control(bctl);
+
+        mutex_unlock(&fs_info->balance_mutex);
+        mutex_unlock(&fs_info->volume_mutex);
 out:
         btrfs_free_path(path);
         return ret;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 74366f27a76b..e1b1a649fc5a 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -281,7 +281,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
 int btrfs_init_new_device(struct btrfs_root *root, char *path);
 int btrfs_balance(struct btrfs_balance_control *bctl,
                   struct btrfs_ioctl_balance_args *bargs);
-int btrfs_recover_balance(struct btrfs_root *tree_root);
+int btrfs_recover_balance(struct btrfs_fs_info *fs_info);
 int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);