From: David Sterba <[email protected]>
[ Upstream commit ceb21a8db48559fd0809e03c4df9eb37743d9170 ]
The device-replace read lock is going to use rw semaphore in followup
commits. The semaphore might sleep which 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 <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
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..6f81f3e88b6d 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
