Add new function btrfs_delete_subvolume() which is almost identical to the secand half of btrfs_ioctl_snap_destroy(). This function requires inode_lock for both @dir and inode of @dentry.
This performes additional check (1. send is not in progress. 2. the subvolume is not a default subvolume. 3. the subvolume does not contain other subvoume) and actual deletion process. The code path is not changed yet and this function will be used to refactor btrfs_ioctl_snap_destroy() and to allow rmdir(2) to delete an empty subvolume. Signed-off-by: Tomohiro Misono <misono.tomoh...@jp.fujitsu.com> --- fs/btrfs/ctree.h | 1 + fs/btrfs/inode.c | 139 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 140 insertions(+) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 2dbead106aab..618365eb9d84 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3167,6 +3167,7 @@ int btrfs_unlink_subvol(struct btrfs_trans_handle *trans, struct inode *dir, u64 objectid, const char *name, int name_len); noinline int may_destroy_subvol(struct btrfs_root *root); +int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry); int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, int front); int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index db66fa4fede6..54c50a9fa2ee 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4387,6 +4387,145 @@ noinline int may_destroy_subvol(struct btrfs_root *root) return ret; } +int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry) +{ + struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb); + struct btrfs_root *root = BTRFS_I(dir)->root; + struct inode *inode = d_inode(dentry); + struct btrfs_root *dest = BTRFS_I(inode)->root; + struct btrfs_trans_handle *trans; + struct btrfs_block_rsv block_rsv; + u64 root_flags; + u64 qgroup_reserved; + int ret; + int err; + + /* + * Don't allow to delete a subvolume with send in progress. This is + * inside the i_mutex so the error handling that has to drop the bit + * again is not run concurrently. + */ + spin_lock(&dest->root_item_lock); + root_flags = btrfs_root_flags(&dest->root_item); + if (dest->send_in_progress == 0) { + btrfs_set_root_flags(&dest->root_item, + root_flags | BTRFS_ROOT_SUBVOL_DEAD); + spin_unlock(&dest->root_item_lock); + } else { + spin_unlock(&dest->root_item_lock); + btrfs_warn(fs_info, + "Attempt to delete subvolume %llu during send", + dest->root_key.objectid); + err = -EPERM; + return err; + } + + down_write(&fs_info->subvol_sem); + + err = may_destroy_subvol(dest); + if (err) + goto out_up_write; + + btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP); + /* + * One for dir inode, two for dir entries, two for root + * ref/backref. + */ + err = btrfs_subvolume_reserve_metadata(root, &block_rsv, + 5, &qgroup_reserved, true); + if (err) + goto out_up_write; + + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + goto out_release; + } + trans->block_rsv = &block_rsv; + trans->bytes_reserved = block_rsv.size; + + btrfs_record_snapshot_destroy(trans, BTRFS_I(dir)); + + ret = btrfs_unlink_subvol(trans, root, dir, + dest->root_key.objectid, + dentry->d_name.name, + dentry->d_name.len); + if (ret) { + err = ret; + btrfs_abort_transaction(trans, ret); + goto out_end_trans; + } + + btrfs_record_root_in_trans(trans, dest); + + memset(&dest->root_item.drop_progress, 0, + sizeof(dest->root_item.drop_progress)); + dest->root_item.drop_level = 0; + btrfs_set_root_refs(&dest->root_item, 0); + + if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) { + ret = btrfs_insert_orphan_item(trans, + fs_info->tree_root, + dest->root_key.objectid); + if (ret) { + btrfs_abort_transaction(trans, ret); + err = ret; + goto out_end_trans; + } + } + + ret = btrfs_uuid_tree_rem(trans, fs_info, dest->root_item.uuid, + BTRFS_UUID_KEY_SUBVOL, + dest->root_key.objectid); + if (ret && ret != -ENOENT) { + btrfs_abort_transaction(trans, ret); + err = ret; + goto out_end_trans; + } + if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) { + ret = btrfs_uuid_tree_rem(trans, fs_info, + dest->root_item.received_uuid, + BTRFS_UUID_KEY_RECEIVED_SUBVOL, + dest->root_key.objectid); + if (ret && ret != -ENOENT) { + btrfs_abort_transaction(trans, ret); + err = ret; + goto out_end_trans; + } + } + +out_end_trans: + trans->block_rsv = NULL; + trans->bytes_reserved = 0; + ret = btrfs_end_transaction(trans); + if (ret && !err) + err = ret; + inode->i_flags |= S_DEAD; +out_release: + btrfs_subvolume_release_metadata(fs_info, &block_rsv); +out_up_write: + up_write(&fs_info->subvol_sem); + if (err) { + spin_lock(&dest->root_item_lock); + root_flags = btrfs_root_flags(&dest->root_item); + btrfs_set_root_flags(&dest->root_item, + root_flags & ~BTRFS_ROOT_SUBVOL_DEAD); + spin_unlock(&dest->root_item_lock); + } else { + d_invalidate(dentry); + btrfs_invalidate_inodes(dest); + ASSERT(dest->send_in_progress == 0); + + /* the last ref */ + if (dest->ino_cache_inode) { + iput(dest->ino_cache_inode); + dest->ino_cache_inode = NULL; + } + } + + return err; +} + static int btrfs_rmdir(struct inode *dir, struct dentry *dentry) { struct inode *inode = d_inode(dentry); -- 2.14.3 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html