From a4c853af0c511d7e0f7cb306bbc8a4f1dbdb64ca Mon Sep 17 00:00:00 2001
From: ChenXiaoSong <chenxiaosong2@huawei.com>
Date: Wed, 16 Nov 2022 22:23:53 +0800
Subject: [PATCH] btrfs: add might_sleep() annotations
Add annotations to functions that might sleep due to allocations or IO
and could be called from various contexts. In case of btrfs_search_slot
it's not obvious why it would sleep:
btrfs_search_slot
setup_nodes_for_search
reada_for_balance
btrfs_readahead_node_child
btrfs_readahead_tree_block
btrfs_find_create_tree_block
alloc_extent_buffer
kmem_cache_zalloc
/* allocate memory non-atomically, might sleep */
kmem_cache_alloc(GFP_NOFS|__GFP_NOFAIL|__GFP_ZERO)
read_extent_buffer_pages
submit_extent_page
/* disk IO, might sleep */
submit_one_bio
Other examples where the sleeping could happen is in 3 places might
sleep in update_qgroup_limit_item(), as shown below:
update_qgroup_limit_item
btrfs_alloc_path
/* allocate memory non-atomically, might sleep */
kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS)
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/ctree.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 76b99bcc849d..4754c9101a4c 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -184,6 +184,8 @@ size_t __attribute_const__ btrfs_get_num_csums(void)
struct btrfs_path *btrfs_alloc_path(void)
{
+ might_sleep();
+
return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
}
@@ -2046,6 +2048,8 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
int min_write_lock_level;
int prev_cmp;
+ might_sleep();
+
lowest_level = p->lowest_level;
WARN_ON(lowest_level && ins_len > 0);
WARN_ON(p->nodes[0] != NULL);
--
2.30.9