hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

btrfs: assert we have a write lock when removing and replacing extent maps 

Removing or replacing an extent map requires holding a write lock on the
extent map's tree. We currently do that everywhere, except in one of the
self tests, where it's harmless since there's no concurrency.

In order to catch possible races in the future, assert that we are holding
a write lock on the extent map tree before removing or replacing an extent
map in the tree, and update the self test to obtain a write lock before
removing extent maps.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2022-02-03 15:36:45 +00:00 committed by David Sterba
parent ad3fc7946b
commit 6d3b050efa
2 changed files with 6 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/btrfs/extent_map.c
View File

@ -492,6 +492,8 @@ struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
*/
void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
{
lockdep_assert_held_write(&tree->lock);
WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
rb_erase_cached(&em->rb_node, &tree->map);
if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags))
@ -506,6 +508,8 @@ void replace_extent_mapping(struct extent_map_tree *tree,
struct extent_map *new,
int modified)
{
lockdep_assert_held_write(&tree->lock);
WARN_ON(test_bit(EXTENT_FLAG_PINNED, &cur->flags));
ASSERT(extent_map_in_tree(cur));
if (!test_bit(EXTENT_FLAG_LOGGING, &cur->flags))

2
fs/btrfs/tests/extent-map-tests.c
View File

@ -15,6 +15,7 @@ static void free_extent_map_tree(struct extent_map_tree *em_tree)
struct extent_map *em;
struct rb_node *node;
write_lock(&em_tree->lock);
while (!RB_EMPTY_ROOT(&em_tree->map.rb_root)) {
node = rb_first_cached(&em_tree->map);
em = rb_entry(node, struct extent_map, rb_node);
@ -32,6 +33,7 @@ static void free_extent_map_tree(struct extent_map_tree *em_tree)
#endif
free_extent_map(em);
}
write_unlock(&em_tree->lock);
}
/*