[36/43] btrfs: hold a ref on the root in open_ctree

Message ID	20200117212602.6737-37-josef@toxicpanda.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=6qVc=3G=vger.kernel.org=linux-btrfs-owner@kernel.org> From: Josef Bacik <josef@toxicpanda.com> To: linux-btrfs@vger.kernel.org, kernel-team@fb.com Subject: [PATCH 36/43] btrfs: hold a ref on the root in open_ctree Date: Fri, 17 Jan 2020 16:25:55 -0500 Message-Id: <20200117212602.6737-37-josef@toxicpanda.com> In-Reply-To: <20200117212602.6737-1-josef@toxicpanda.com> References: <20200117212602.6737-1-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 [00/43,v4] Cleanup how we handle root refs, part 1 [01/43] btrfs: push __setup_root into btrfs_alloc_root [02/43] btrfs: move fs root init stuff into btrfs_init_fs_root [03/43] btrfs: make btrfs_find_orphan_roots use btrfs_get_fs_root [04/43] btrfs: export and use btrfs_read_tree_root [05/43] btrfs: make relocation use btrfs_read_tree_root() [06/43] btrfs: kill btrfs_read_fs_root [07/43] btrfs: kill the btrfs_read_fs_root_no_name helper [08/43] btrfs: make the fs root init functions static [09/43] btrfs: handle NULL roots in btrfs_put/btrfs_grab_fs_root [10/43] btrfs: hold a ref on fs roots while they're in the radix tree [11/43] btrfs: hold a ref on the root in resolve_indirect_ref [12/43] btrfs: hold a root ref in btrfs_get_dentry [13/43] btrfs: hold a ref on the root in __btrfs_run_defrag_inode [14/43] btrfs: hold a ref on the root in fixup_tree_root_location [15/43] btrfs: hold a ref on the root in create_subvol [16/43] btrfs: hold a ref on the root in search_ioctl [17/43] btrfs: hold a ref on the root in btrfs_search_path_in_tree [18/43] btrfs: hold a ref on the root in btrfs_search_path_in_tree_user [19/43] btrfs: hold a ref on the root in btrfs_ioctl_get_subvol_info [20/43] btrfs: hold ref on root in btrfs_ioctl_default_subvol [21/43] btrfs: hold a ref on the root in build_backref_tree [22/43] btrfs: hold a ref on the root in prepare_to_merge [23/43] btrfs: hold a ref on the root in merge_reloc_roots [24/43] btrfs: hold a ref on the root in record_reloc_root_in_trans [25/43] btrfs: hold a ref on the root in find_data_references [26/43] btrfs: hold a ref on the root in create_reloc_inode [27/43] btrfs: hold a ref on the root in btrfs_recover_relocation [28/43] btrfs: push grab_fs_root into read_fs_root [29/43] btrfs: hold a ref for the root in btrfs_find_orphan_roots [30/43] btrfs: hold a ref on the root in scrub_print_warning_inode [31/43] btrfs: hold a ref on the root in btrfs_ioctl_send [32/43] btrfs: hold a ref on the root in get_subvol_name_from_objectid [33/43] btrfs: hold a ref on the root in create_pending_snapshot [34/43] btrfs: hold a ref on the root in btrfs_recover_log_trees [35/43] btrfs: hold a ref on the root in btrfs_check_uuid_tree_entry [36/43] btrfs: hold a ref on the root in open_ctree [37/43] btrfs: use btrfs_put_fs_root to free roots always [38/43] btrfs: push btrfs_grab_fs_root into btrfs_get_fs_root [39/43] btrfs: free more things in btrfs_free_fs_info [40/43] btrfs: move fs_info init work into it's own helper function [41/43] btrfs: make the init of static elements in fs_info separate [42/43] btrfs: add a leak check for roots [43/43] btrfs: rename btrfs_put_fs_root and btrfs_grab_fs_root

Message ID

20200117212602.6737-37-josef@toxicpanda.com (mailing list archive)

State

New, archived

Headers

From: Josef Bacik <josef@toxicpanda.com>
To: linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH 36/43] btrfs: hold a ref on the root in open_ctree
Date: Fri, 17 Jan 2020 16:25:55 -0500
Message-Id: <20200117212602.6737-37-josef@toxicpanda.com>
In-Reply-To: <20200117212602.6737-1-josef@toxicpanda.com>
References: <20200117212602.6737-1-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

Commit Message

Josef Bacik Jan. 17, 2020, 9:25 p.m. UTC

We lookup the fs_root and put it in our fs_info directly, we should hold
a ref on this root for the lifetime of the fs_info.  Rework the free'ing
function so that it calls btrfs_put_fs_root() on the root at free time
with all of the other global trees.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/ctree.h   | 17 -----------------
 fs/btrfs/disk-io.c | 26 ++++++++++++++++++++++++++
 fs/btrfs/disk-io.h |  1 +
 fs/btrfs/super.c   |  6 +++---
 4 files changed, 30 insertions(+), 20 deletions(-)

Comments

Nikolay Borisov Jan. 22, 2020, 10:48 a.m. UTC | #1

On 17.01.20 г. 23:25 ч., Josef Bacik wrote:
> We lookup the fs_root and put it in our fs_info directly, we should hold
> a ref on this root for the lifetime of the fs_info.  Rework the free'ing
> function so that it calls btrfs_put_fs_root() on the root at free time
> with all of the other global trees.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>

So you not only hold a ref here but also refactor some cleanup code.
This definitely needs to be split into separate patches.

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f90b82050d2d..68510af4cacf 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2697,23 +2697,6 @@  static inline int btrfs_need_cleaner_sleep(struct btrfs_fs_info *fs_info)
 	return fs_info->sb->s_flags & SB_RDONLY || btrfs_fs_closing(fs_info);
 }
 
-static inline void free_fs_info(struct btrfs_fs_info *fs_info)
-{
-	kfree(fs_info->balance_ctl);
-	kfree(fs_info->delayed_root);
-	kfree(fs_info->extent_root);
-	kfree(fs_info->tree_root);
-	kfree(fs_info->chunk_root);
-	kfree(fs_info->dev_root);
-	kfree(fs_info->csum_root);
-	kfree(fs_info->quota_root);
-	kfree(fs_info->uuid_root);
-	kfree(fs_info->free_space_root);
-	kfree(fs_info->super_copy);
-	kfree(fs_info->super_for_commit);
-	kvfree(fs_info);
-}
-
 /* tree mod log functions from ctree.c */
 u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
 			   struct seq_list *elem);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5f672f016ed8..433c29ddfca7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1523,6 +1523,25 @@  int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
+void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
+{
+	kfree(fs_info->balance_ctl);
+	kfree(fs_info->delayed_root);
+	kfree(fs_info->extent_root);
+	kfree(fs_info->tree_root);
+	kfree(fs_info->chunk_root);
+	kfree(fs_info->dev_root);
+	kfree(fs_info->csum_root);
+	kfree(fs_info->quota_root);
+	kfree(fs_info->uuid_root);
+	kfree(fs_info->free_space_root);
+	kfree(fs_info->super_copy);
+	kfree(fs_info->super_for_commit);
+	btrfs_put_fs_root(fs_info->fs_root);
+	kvfree(fs_info);
+}
+
+
 struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
 				     struct btrfs_key *location,
 				     bool check_ref)
@@ -3185,6 +3204,13 @@  int __cold open_ctree(struct super_block *sb,
 		goto fail_qgroup;
 	}
 
+	if (!btrfs_grab_fs_root(fs_info->fs_root)) {
+		fs_info->fs_root = NULL;
+		err = -ENOENT;
+		btrfs_warn(fs_info, "failed to grab a ref on the fs tree");
+		goto fail_qgroup;
+	}
+
 	if (sb_rdonly(sb))
 		return 0;
 
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 8add2e14aab1..97e7ac474a52 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -68,6 +68,7 @@  struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
 				     struct btrfs_key *key,
 				     bool check_ref);
 
+void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);
 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info);
 void btrfs_btree_balance_dirty(struct btrfs_fs_info *fs_info);
 void btrfs_btree_balance_dirty_nodelay(struct btrfs_fs_info *fs_info);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 5c3a1b7de6ee..0c81456df23e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1580,7 +1580,7 @@  static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
 
 	if (s->s_root) {
 		btrfs_close_devices(fs_devices);
-		free_fs_info(fs_info);
+		btrfs_free_fs_info(fs_info);
 		if ((flags ^ s->s_flags) & SB_RDONLY)
 			error = -EBUSY;
 	} else {
@@ -1603,7 +1603,7 @@  static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
 error_close_devices:
 	btrfs_close_devices(fs_devices);
 error_fs_info:
-	free_fs_info(fs_info);
+	btrfs_free_fs_info(fs_info);
 error_sec_opts:
 	security_free_mnt_opts(&new_sec_opts);
 	return ERR_PTR(error);
@@ -2169,7 +2169,7 @@  static void btrfs_kill_super(struct super_block *sb)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 	kill_anon_super(sb);
-	free_fs_info(fs_info);
+	btrfs_free_fs_info(fs_info);
 }
 
 static struct file_system_type btrfs_fs_type = {

[36/43] btrfs: hold a ref on the root in open_ctree

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