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Btrfs: add snapshot/subvolume destroy ioctl

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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 <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Yan, Zheng
2009-09-21 16:00:26 -04:00
committed by Chris Mason
parent 4df27c4d5c
commit 76dda93c6a
12 changed files with 610 additions and 238 deletions
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81
fs/btrfs/disk-io.c
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@ -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);