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Commit ceb21a8d authored by David Sterba's avatar David Sterba
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btrfs: reada: reorder dev-replace locks before radix tree preload 



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: default avatarDavid Sterba <dsterba@suse.com>
parent d1051d6e

fs/btrfs/reada.c

+7 −5
Original line number Diff line number Diff line
@@ -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();