1 files changed, 33 insertions, 54 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 57080dffdfc6..17ee7fc5e64e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -197,7 +197,7 @@ static match_table_t tokens = {
         {Opt_subvolrootid, "subvolrootid=%d"},
         {Opt_defrag, "autodefrag"},
         {Opt_inode_cache, "inode_cache"},
-        {Opt_no_space_cache, "no_space_cache"},
+        {Opt_no_space_cache, "nospace_cache"},
         {Opt_recovery, "recovery"},
         {Opt_err, NULL},
 };
@@ -448,6 +448,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
                 token = match_token(p, tokens, args);
                 switch (token) {
                 case Opt_subvol:
+                        kfree(*subvol_name);
                         *subvol_name = match_strdup(&args[0]);
                         break;
                 case Opt_subvolid:
@@ -710,7 +711,7 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
         if (btrfs_test_opt(root, SPACE_CACHE))
                 seq_puts(seq, ",space_cache");
         else
-                seq_puts(seq, ",no_space_cache");
+                seq_puts(seq, ",nospace_cache");
         if (btrfs_test_opt(root, CLEAR_CACHE))
                 seq_puts(seq, ",clear_cache");
         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
@@ -824,13 +825,9 @@ static char *setup_root_args(char *args)
 static struct dentry *mount_subvol(const char *subvol_name, int flags,
                                    const char *device_name, char *data)
 {
-        struct super_block *s;
         struct dentry *root;
         struct vfsmount *mnt;
-        struct mnt_namespace *ns_private;
         char *newargs;
-        struct path path;
-        int error;
 
         newargs = setup_root_args(data);
         if (!newargs)
@@ -841,39 +838,17 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags,
         if (IS_ERR(mnt))
                 return ERR_CAST(mnt);
 
-        ns_private = create_mnt_ns(mnt);
-        if (IS_ERR(ns_private)) {
-                mntput(mnt);
-                return ERR_CAST(ns_private);
-        }
-
-        /*
-         * This will trigger the automount of the subvol so we can just
-         * drop the mnt we have here and return the dentry that we
-         * found.
-         */
-        error = vfs_path_lookup(mnt->mnt_root, mnt, subvol_name,
-                                LOOKUP_FOLLOW, &path);
-        put_mnt_ns(ns_private);
-        if (error)
-                return ERR_PTR(error);
+        root = mount_subtree(mnt, subvol_name);
 
-        if (!is_subvolume_inode(path.dentry->d_inode)) {
-                path_put(&path);
-                mntput(mnt);
-                error = -EINVAL;
+        if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
+                struct super_block *s = root->d_sb;
+                dput(root);
+                root = ERR_PTR(-EINVAL);
+                deactivate_locked_super(s);
                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
                                 subvol_name);
-                return ERR_PTR(-EINVAL);
         }
 
-        /* Get a ref to the sb and the dentry we found and return it */
-        s = path.mnt->mnt_sb;
-        atomic_inc(&s->s_active);
-        root = dget(path.dentry);
-        path_put(&path);
-        down_write(&s->s_umount);
-
         return root;
 }
 
@@ -890,7 +865,6 @@ 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;
@@ -904,8 +878,10 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         error = btrfs_parse_early_options(data, mode, fs_type,
                                           &subvol_name, &subvol_objectid,
                                           &subvol_rootid, &fs_devices);
-        if (error)
+        if (error) {
+                kfree(subvol_name);
                 return ERR_PTR(error);
+        }
 
         if (subvol_name) {
                 root = mount_subvol(subvol_name, flags, device_name, data);
@@ -917,15 +893,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         if (error)
                 return ERR_PTR(error);
 
-        error = btrfs_open_devices(fs_devices, mode, fs_type);
-        if (error)
-                return ERR_PTR(error);
-
-        if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
-                error = -EACCES;
-                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
@@ -933,24 +900,36 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
          * 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) {
+        if (!fs_info)
+                return ERR_PTR(-ENOMEM);
+
+        fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+        if (!fs_info->tree_root) {
                 error = -ENOMEM;
-                goto error_close_devices;
+                goto error_fs_info;
         }
-        fs_info->tree_root = tree_root;
+        fs_info->tree_root->fs_info = fs_info;
         fs_info->fs_devices = fs_devices;
-        tree_root->fs_info = fs_info;
 
         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
         if (!fs_info->super_copy || !fs_info->super_for_commit) {
                 error = -ENOMEM;
+                goto error_fs_info;
+        }
+
+        error = btrfs_open_devices(fs_devices, mode, fs_type);
+        if (error)
+                goto error_fs_info;
+
+        if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
+                error = -EACCES;
                 goto error_close_devices;
         }
 
         bdev = fs_devices->latest_bdev;
-        s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
+        s = sget(fs_type, btrfs_test_super, btrfs_set_super,
+                 fs_info->tree_root);
         if (IS_ERR(s)) {
                 error = PTR_ERR(s);
                 goto error_close_devices;
@@ -959,12 +938,12 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         if (s->s_root) {
                 if ((flags ^ s->s_flags) & MS_RDONLY) {
                         deactivate_locked_super(s);
-                        return ERR_PTR(-EBUSY);
+                        error = -EBUSY;
+                        goto error_close_devices;
                 }
 
                 btrfs_close_devices(fs_devices);
                 free_fs_info(fs_info);
-                kfree(tree_root);
         } else {
                 char b[BDEVNAME_SIZE];
 
@@ -991,8 +970,8 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 
 error_close_devices:
         btrfs_close_devices(fs_devices);
+error_fs_info:
         free_fs_info(fs_info);
-        kfree(tree_root);
         return ERR_PTR(error);
 }