diff mbox series

[22/44] btrfs: hold a ref on the root in prepare_to_merge

Message ID	20200124143301.2186319-23-josef@toxicpanda.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=Oo12=3N=vger.kernel.org=linux-btrfs-owner@kernel.org> From: Josef Bacik <josef@toxicpanda.com> To: kernel-team@fb.com, linux-btrfs@vger.kernel.org Subject: [PATCH 22/44] btrfs: hold a ref on the root in prepare_to_merge Date: Fri, 24 Jan 2020 09:32:39 -0500 Message-Id: <20200124143301.2186319-23-josef@toxicpanda.com> In-Reply-To: <20200124143301.2186319-1-josef@toxicpanda.com> References: <20200124143301.2186319-1-josef@toxicpanda.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk
Series	Cleanup how we handle root refs, part 1 \| expand [00/44,v5] Cleanup how we handle root refs, part 1 [01/44] btrfs: push __setup_root into btrfs_alloc_root [02/44] btrfs: move fs root init stuff into btrfs_init_fs_root [03/44] btrfs: make btrfs_find_orphan_roots use btrfs_get_fs_root [04/44] btrfs: export and use btrfs_read_tree_root [05/44] btrfs: make relocation use btrfs_read_tree_root() [06/44] btrfs: kill btrfs_read_fs_root [07/44] btrfs: kill the btrfs_read_fs_root_no_name helper [08/44] btrfs: make the fs root init functions static [09/44] btrfs: handle NULL roots in btrfs_put/btrfs_grab_fs_root [10/44] btrfs: hold a ref on fs roots while they're in the radix tree [11/44] btrfs: hold a ref on the root in resolve_indirect_ref [12/44] btrfs: hold a root ref in btrfs_get_dentry [13/44] btrfs: hold a ref on the root in __btrfs_run_defrag_inode [14/44] btrfs: hold a ref on the root in fixup_tree_root_location [15/44] btrfs: hold a ref on the root in create_subvol [16/44] btrfs: hold a ref on the root in search_ioctl [17/44] btrfs: hold a ref on the root in btrfs_search_path_in_tree [18/44] btrfs: hold a ref on the root in btrfs_search_path_in_tree_user [19/44] btrfs: hold a ref on the root in btrfs_ioctl_get_subvol_info [20/44] btrfs: hold ref on root in btrfs_ioctl_default_subvol [21/44] btrfs: hold a ref on the root in build_backref_tree [22/44] btrfs: hold a ref on the root in prepare_to_merge [23/44] btrfs: hold a ref on the root in merge_reloc_roots [24/44] btrfs: hold a ref on the root in record_reloc_root_in_trans [25/44] btrfs: hold a ref on the root in find_data_references [26/44] btrfs: hold a ref on the root in create_reloc_inode [27/44] btrfs: hold a ref on the root in btrfs_recover_relocation [28/44] btrfs: push grab_fs_root into read_fs_root [29/44] btrfs: hold a ref for the root in btrfs_find_orphan_roots [30/44] btrfs: hold a ref on the root in scrub_print_warning_inode [31/44] btrfs: hold a ref on the root in btrfs_ioctl_send [32/44] btrfs: hold a ref on the root in get_subvol_name_from_objectid [33/44] btrfs: hold a ref on the root in create_pending_snapshot [34/44] btrfs: hold a ref on the root in btrfs_recover_log_trees [35/44] btrfs: hold a ref on the root in btrfs_check_uuid_tree_entry [36/44] btrfs: move free_fs_info [37/44] btrfs: hold a ref on the root in open_ctree [38/44] btrfs: use btrfs_put_fs_root to free roots always [39/44] btrfs: push btrfs_grab_fs_root into btrfs_get_fs_root [40/44] btrfs: free more things in btrfs_free_fs_info [41/44] btrfs: move fs_info init work into it's own helper function [42/44] btrfs: make the init of static elements in fs_info separate [43/44] btrfs: add a leak check for roots [44/44] btrfs: rename btrfs_put_fs_root and btrfs_grab_fs_root

Commit Message

Josef Bacik Jan. 24, 2020, 2:32 p.m. UTC

We look up the reloc roots corresponding root, we need to hold a ref on
that root.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/relocation.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

David Sterba Feb. 5, 2020, 2:52 p.m. UTC | #1

On Fri, Jan 24, 2020 at 09:32:39AM -0500, Josef Bacik wrote:
> We look up the reloc roots corresponding root, we need to hold a ref on
> that root.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
>  fs/btrfs/relocation.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 990595a27a15..53df57b59bc3 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -2474,6 +2474,8 @@ int prepare_to_merge(struct reloc_control *rc, int err)
>  		list_del_init(&reloc_root->root_list);
>  
>  		root = read_fs_root(fs_info, reloc_root->root_key.offset);
> +		if (!btrfs_grab_fs_root(root))
> +			BUG();
>  		BUG_ON(IS_ERR(root));

These two should be swapped, first the root is "checked" if it's
valid, then the reference can be grabbed. The code is later pushed into
the other helper and there it's in the right order so it's only
temporary.

>  		BUG_ON(root->reloc_root != reloc_root);
>

diff mbox series

Patch

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 990595a27a15..53df57b59bc3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2474,6 +2474,8 @@  int prepare_to_merge(struct reloc_control *rc, int err)
 		list_del_init(&reloc_root->root_list);
 
 		root = read_fs_root(fs_info, reloc_root->root_key.offset);
+		if (!btrfs_grab_fs_root(root))
+			BUG();
 		BUG_ON(IS_ERR(root));
 		BUG_ON(root->reloc_root != reloc_root);
 
@@ -2486,6 +2488,7 @@  int prepare_to_merge(struct reloc_control *rc, int err)
 		btrfs_update_reloc_root(trans, root);
 
 		list_add(&reloc_root->root_list, &reloc_roots);
+		btrfs_put_fs_root(root);
 	}
 
 	list_splice(&reloc_roots, &rc->reloc_roots);