Btrfs: add snapshot/subvolume destroy ioctl

[cascardo/linux.git] / fs / btrfs / disk-io.c

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a4f5310..a0d41e7 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1378,8 +1378,10 @@ static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
 
        err = bdi_register(bdi, NULL, "btrfs-%d",
                                atomic_inc_return(&btrfs_bdi_num));
-       if (err)
+       if (err) {
+               bdi_destroy(bdi);
                return err;
+       }
 
        bdi->ra_pages   = default_backing_dev_info.ra_pages;
        bdi->unplug_io_fn       = btrfs_unplug_io_fn;
@@ -1469,9 +1471,12 @@ static int cleaner_kthread(void *arg)
                        break;
 
                vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
-               mutex_lock(&root->fs_info->cleaner_mutex);
-               btrfs_clean_old_snapshots(root);
-               mutex_unlock(&root->fs_info->cleaner_mutex);
+
+               if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
+                   mutex_trylock(&root->fs_info->cleaner_mutex)) {
+                       btrfs_clean_old_snapshots(root);
+                       mutex_unlock(&root->fs_info->cleaner_mutex);
+               }
 
                if (freezing(current)) {
                        refrigerator();
@@ -1576,7 +1581,26 @@ struct btrfs_root *open_ctree(struct super_block *sb,
                err = -ENOMEM;
                goto fail;
        }
-       INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
+
+       ret = init_srcu_struct(&fs_info->subvol_srcu);
+       if (ret) {
+               err = ret;
+               goto fail;
+       }
+
+       ret = setup_bdi(fs_info, &fs_info->bdi);
+       if (ret) {
+               err = ret;
+               goto fail_srcu;
+       }
+
+       fs_info->btree_inode = new_inode(sb);
+       if (!fs_info->btree_inode) {
+               err = -ENOMEM;
+               goto fail_bdi;
+       }
+
+       INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
        INIT_LIST_HEAD(&fs_info->trans_list);
        INIT_LIST_HEAD(&fs_info->dead_roots);
        INIT_LIST_HEAD(&fs_info->hashers);
@@ -1586,6 +1610,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
        spin_lock_init(&fs_info->delalloc_lock);
        spin_lock_init(&fs_info->new_trans_lock);
        spin_lock_init(&fs_info->ref_cache_lock);
+       spin_lock_init(&fs_info->fs_roots_radix_lock);
 
        init_completion(&fs_info->kobj_unregister);
        fs_info->tree_root = tree_root;
@@ -1604,11 +1629,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
        fs_info->sb = sb;
        fs_info->max_extent = (u64)-1;
        fs_info->max_inline = 8192 * 1024;
-       if (setup_bdi(fs_info, &fs_info->bdi))
-               goto fail_bdi;
-       fs_info->btree_inode = new_inode(sb);
-       fs_info->btree_inode->i_ino = 1;
-       fs_info->btree_inode->i_nlink = 1;
        fs_info->metadata_ratio = 8;
 
        fs_info->thread_pool_size = min_t(unsigned long,
@@ -1620,6 +1640,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
        sb->s_blocksize = 4096;
        sb->s_blocksize_bits = blksize_bits(4096);
 
+       fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
+       fs_info->btree_inode->i_nlink = 1;
        /*
         * we set the i_size on the btree inode to the max possible int.
         * the real end of the address space is determined by all of
@@ -1638,6 +1660,11 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 
        BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
 
+       BTRFS_I(fs_info->btree_inode)->root = tree_root;
+       memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
+              sizeof(struct btrfs_key));
+       BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
+
        spin_lock_init(&fs_info->block_group_cache_lock);
        fs_info->block_group_cache_tree.rb_node = NULL;
 
@@ -1648,21 +1675,16 @@ struct btrfs_root *open_ctree(struct super_block *sb,
        fs_info->pinned_extents = &fs_info->freed_extents[0];
        fs_info->do_barriers = 1;
 
-       BTRFS_I(fs_info->btree_inode)->root = tree_root;
-       memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
-              sizeof(struct btrfs_key));
-       insert_inode_hash(fs_info->btree_inode);
 
        mutex_init(&fs_info->trans_mutex);
        mutex_init(&fs_info->ordered_operations_mutex);
        mutex_init(&fs_info->tree_log_mutex);
-       mutex_init(&fs_info->drop_mutex);
        mutex_init(&fs_info->chunk_mutex);
        mutex_init(&fs_info->transaction_kthread_mutex);
        mutex_init(&fs_info->cleaner_mutex);
        mutex_init(&fs_info->volume_mutex);
-       mutex_init(&fs_info->tree_reloc_mutex);
        init_rwsem(&fs_info->extent_commit_sem);
+       init_rwsem(&fs_info->subvol_sem);
 
        btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
        btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
@@ -1941,6 +1963,9 @@ printk("thread pool is %d\n", fs_info->thread_pool_size);
                }
        }
 
+       ret = btrfs_find_orphan_roots(tree_root);
+       BUG_ON(ret);
+
        if (!(sb->s_flags & MS_RDONLY)) {
                ret = btrfs_recover_relocation(tree_root);
                BUG_ON(ret);
@@ -2000,6 +2025,8 @@ fail_iput:
        btrfs_mapping_tree_free(&fs_info->mapping_tree);
 fail_bdi:
        bdi_destroy(&fs_info->bdi);
+fail_srcu:
+       cleanup_srcu_struct(&fs_info->subvol_srcu);
 fail:
        kfree(extent_root);
        kfree(tree_root);
@@ -2263,6 +2290,10 @@ int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
        radix_tree_delete(&fs_info->fs_roots_radix,
                          (unsigned long)root->root_key.objectid);
        spin_unlock(&fs_info->fs_roots_radix_lock);
+
+       if (btrfs_root_refs(&root->root_item) == 0)
+               synchronize_srcu(&fs_info->subvol_srcu);
+
        free_fs_root(root);
        return 0;
 }
@@ -2286,6 +2317,20 @@ static int del_fs_roots(struct btrfs_fs_info *fs_info)
        struct btrfs_root *gang[8];
        int i;
 
+       while (!list_empty(&fs_info->dead_roots)) {
+               gang[0] = list_entry(fs_info->dead_roots.next,
+                                    struct btrfs_root, root_list);
+               list_del(&gang[0]->root_list);
+
+               if (gang[0]->in_radix) {
+                       btrfs_free_fs_root(fs_info, gang[0]);
+               } else {
+                       free_extent_buffer(gang[0]->node);
+                       free_extent_buffer(gang[0]->commit_root);
+                       kfree(gang[0]);
+               }
+       }
+
        while (1) {
                ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
                                             (void **)gang, 0,
@@ -2315,9 +2360,6 @@ int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
                root_objectid = gang[ret - 1]->root_key.objectid + 1;
                for (i = 0; i < ret; i++) {
                        root_objectid = gang[i]->root_key.objectid;
-                       ret = btrfs_find_dead_roots(fs_info->tree_root,
-                                                   root_objectid);
-                       BUG_ON(ret);
                        btrfs_orphan_cleanup(gang[i]);
                }
                root_objectid++;
@@ -2405,6 +2447,7 @@ int close_ctree(struct btrfs_root *root)
        btrfs_mapping_tree_free(&fs_info->mapping_tree);
 
        bdi_destroy(&fs_info->bdi);
+       cleanup_srcu_struct(&fs_info->subvol_srcu);
 
        kfree(fs_info->extent_root);
        kfree(fs_info->tree_root);