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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: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-08-24 19:35:04 +02:00
parent d1051d6ebf
commit ceb21a8db4
1 changed files with 9 additions and 7 deletions
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16
fs/btrfs/reada.c
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@ -376,26 +376,28 @@ static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info,
goto error;
}
ret = radix_tree_preload(GFP_KERNEL);
if (ret)
goto error;
/* insert extent in reada_tree + all per-device trees, all or nothing */
/* 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) {
btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
goto error;
}
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();