From: David Sterba <dsterba@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: David Sterba <dsterba@suse.com>
Subject: [PATCH 1/4] btrfs: reada: reorder dev-replace locks before radix tree preload
Date: Tue, 20 Nov 2018 13:50:59 +0100 [thread overview]
Message-ID: <f1539c9e96bbf5f2888286728aa342df030bfae1.1542717531.git.dsterba@suse.com> (raw)
In-Reply-To: <cover.1542717531.git.dsterba@suse.com>
The read lock is going to use rw semaphore that might sleep, this is not
possible in the radix tree preload section. The lock nesting is now:
* device replace
* radix tree preload
* readahead spinlock
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/reada.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index dec14b739b10..6c4fdd98582d 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -376,26 +376,28 @@ static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info,
goto error;
}
+ /* insert extent in reada_tree + all per-device trees, all or nothing */
+ btrfs_dev_replace_read_lock(&fs_info->dev_replace);
ret = radix_tree_preload(GFP_KERNEL);
- if (ret)
+ if (ret) {
+ btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
goto error;
+ }
- /* insert extent in reada_tree + all per-device trees, all or nothing */
- btrfs_dev_replace_read_lock(&fs_info->dev_replace);
spin_lock(&fs_info->reada_lock);
ret = radix_tree_insert(&fs_info->reada_tree, index, re);
if (ret == -EEXIST) {
re_exist = radix_tree_lookup(&fs_info->reada_tree, index);
re_exist->refcnt++;
spin_unlock(&fs_info->reada_lock);
- btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
radix_tree_preload_end();
+ btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
goto error;
}
if (ret) {
spin_unlock(&fs_info->reada_lock);
- btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
radix_tree_preload_end();
+ btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
goto error;
}
radix_tree_preload_end();
--
2.19.1
next prev parent reply other threads:[~2018-11-20 12:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-20 12:50 [PATCH 0/4] Replace custom device-replace locking with rwsem David Sterba
2018-11-20 12:50 ` David Sterba [this message]
2018-11-20 12:51 ` [PATCH 2/4] btrfs: dev-replace: swich locking to rw semaphore David Sterba
2018-11-20 12:51 ` [PATCH 3/4] btrfs: dev-replace: remove custom read/write blocking scheme David Sterba
2018-11-20 12:51 ` [PATCH 4/4] btrfs: dev-replace: open code trivial locking helpers David Sterba
2018-12-03 17:14 ` [PATCH 0/4] Replace custom device-replace locking with rwsem David Sterba
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