From 76dda93c6ae2c1dc3e6cde34569d6aca26b0c918 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Mon, 21 Sep 2009 16:00:26 -0400 Subject: Btrfs: add snapshot/subvolume destroy ioctl This patch adds snapshot/subvolume destroy ioctl. A subvolume that isn't being used and doesn't contains links to other subvolumes can be destroyed. Signed-off-by: Yan Zheng Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 81 +++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 62 insertions(+), 19 deletions(-) (limited to 'fs/btrfs/disk-io.c') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a4f531047c4..a0d41e713f3 100644 --- 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); 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