1 files changed, 39 insertions, 4 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 8299a25ffc8f..883c6fa1367e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -244,6 +244,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 case Opt_space_cache:
                         printk(KERN_INFO "btrfs: enabling disk space caching\n");
                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
+                        break;
                 case Opt_clear_cache:
                         printk(KERN_INFO "btrfs: force clearing of disk cache\n");
                         btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
@@ -562,12 +563,26 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 
 static int btrfs_test_super(struct super_block *s, void *data)
 {
-        struct btrfs_fs_devices *test_fs_devices = data;
+        struct btrfs_root *test_root = data;
         struct btrfs_root *root = btrfs_sb(s);
 
-        return root->fs_info->fs_devices == test_fs_devices;
+        /*
+         * If this super block is going away, return false as it
+         * can't match as an existing super block.
+         */
+        if (!atomic_read(&s->s_active))
+                return 0;
+        return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
+}
+
+static int btrfs_set_super(struct super_block *s, void *data)
+{
+        s->s_fs_info = data;
+
+        return set_anon_super(s, data);
 }
 
+
 /*
  * Find a superblock for the given device / mount point.
  *
@@ -581,6 +596,8 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         struct super_block *s;
         struct dentry *root;
         struct btrfs_fs_devices *fs_devices = NULL;
+        struct btrfs_root *tree_root = NULL;
+        struct btrfs_fs_info *fs_info = NULL;
         fmode_t mode = FMODE_READ;
         char *subvol_name = NULL;
         u64 subvol_objectid = 0;
@@ -608,8 +625,24 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
                 goto error_close_devices;
         }
 
+        /*
+         * Setup a dummy root and fs_info for test/set super.  This is because
+         * we don't actually fill this stuff out until open_ctree, but we need
+         * it for searching for existing supers, so this lets us do that and
+         * then open_ctree will properly initialize everything later.
+         */
+        fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
+        tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+        if (!fs_info || !tree_root) {
+                error = -ENOMEM;
+                goto error_close_devices;
+        }
+        fs_info->tree_root = tree_root;
+        fs_info->fs_devices = fs_devices;
+        tree_root->fs_info = fs_info;
+
         bdev = fs_devices->latest_bdev;
-        s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
+        s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
         if (IS_ERR(s))
                 goto error_s;
 
@@ -652,9 +685,9 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
                 mutex_unlock(&root->d_inode->i_mutex);
 
                 if (IS_ERR(new_root)) {
+                        dput(root);
                         deactivate_locked_super(s);
                         error = PTR_ERR(new_root);
-                        dput(root);
                         goto error_free_subvol_name;
                 }
                 if (!new_root->d_inode) {
@@ -675,6 +708,8 @@ error_s:
         error = PTR_ERR(s);
 error_close_devices:
         btrfs_close_devices(fs_devices);
+        kfree(fs_info);
+        kfree(tree_root);
 error_free_subvol_name:
         kfree(subvol_name);
         return ERR_PTR(error);