Btrfs: Seed device support

[linux-2.6-block.git] / fs / btrfs / super.c

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index ab9d5e89ed13aab7fbf0a20173bad725404ade73..92393cc60d086a9888088e83f868b180a7c1bac4 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -370,6 +370,9 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
        int ret;
        root = btrfs_sb(sb);
 
+       if (sb->s_flags & MS_RDONLY)
+               return 0;
+
        sb->s_dirt = 0;
        if (!wait) {
                filemap_flush(root->fs_info->btree_inode->i_mapping);
@@ -428,6 +431,11 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
        if (error)
                goto error_free_subvol_name;
 
+       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, set_anon_super, fs_devices);
        if (IS_ERR(s))
@@ -438,9 +446,10 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
                        up_write(&s->s_umount);
                        deactivate_super(s);
                        error = -EBUSY;
-                       goto error_bdev;
+                       goto error_close_devices;
                }
 
+               btrfs_close_devices(fs_devices);
        } else {
                char b[BDEVNAME_SIZE];
 
@@ -487,7 +496,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 
 error_s:
        error = PTR_ERR(s);
-error_bdev:
+error_close_devices:
        btrfs_close_devices(fs_devices);
 error_free_subvol_name:
        kfree(subvol_name);
@@ -495,6 +504,38 @@ error:
        return error;
 }
 
+static int btrfs_remount(struct super_block *sb, int *flags, char *data)
+{
+       struct btrfs_root *root = btrfs_sb(sb);
+       int ret;
+
+       if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
+               return 0;
+
+       if (*flags & MS_RDONLY) {
+               sb->s_flags |= MS_RDONLY;
+
+               ret =  btrfs_commit_super(root);
+               WARN_ON(ret);
+       } else {
+               if (root->fs_info->fs_devices->rw_devices == 0)
+                       return -EACCES;
+
+               if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
+                       return -EINVAL;
+
+               ret = btrfs_cleanup_reloc_trees(root);
+               WARN_ON(ret);
+
+               ret = btrfs_cleanup_fs_roots(root->fs_info);
+               WARN_ON(ret);
+
+               sb->s_flags &= ~MS_RDONLY;
+       }
+
+       return 0;
+}
+
 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
        struct btrfs_root *root = btrfs_sb(dentry->d_sb);
@@ -582,6 +623,7 @@ static struct super_operations btrfs_super_ops = {
        .alloc_inode    = btrfs_alloc_inode,
        .destroy_inode  = btrfs_destroy_inode,
        .statfs         = btrfs_statfs,
+       .remount_fs     = btrfs_remount,
        .write_super_lockfs = btrfs_write_super_lockfs,
        .unlockfs       = btrfs_unlockfs,
 };