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btrfs: assert that extent buffers are write locked instead of only locked

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We currently use lockdep_assert_held() at btrfs_assert_tree_locked(), and
that checks that we hold a lock either in read mode or write mode.

However in all contexts we use btrfs_assert_tree_locked(), we actually
want to check if we are holding a write lock on the extent buffer's rw
semaphore - it would be a bug if in any of those contexts we were holding
a read lock instead.

So change btrfs_assert_tree_locked() to use lockdep_assert_held_write()
instead and, to make it more explicit, rename btrfs_assert_tree_locked()
to btrfs_assert_tree_write_locked(), so that it's clear we want to check
we are holding a write lock.

For now there are no contexts where we want to assert that we must have
a read lock, but in case that is needed in the future, we can add a new
helper function that just calls out lockdep_assert_held_read().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2021-09-22 10:36:45 +01:00 • committed by David Sterba
parent 8ef9dc0f14
commit 49d0c6424c
5 changed files with 15 additions and 14 deletions
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8
fs/btrfs/disk-io.c
View file

@ -1036,7 +1036,7 @@ static int btree_set_page_dirty(struct page *page)
BUG_ON(!eb);
BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
BUG_ON(!atomic_read(&eb->refs));
btrfs_assert_tree_locked(eb);
btrfs_assert_tree_write_locked(eb);
return __set_page_dirty_nobuffers(page);
}
ASSERT(PagePrivate(page) && page->private);
@ -1061,7 +1061,7 @@ static int btree_set_page_dirty(struct page *page)
ASSERT(eb);
ASSERT(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
ASSERT(atomic_read(&eb->refs));
btrfs_assert_tree_locked(eb);
btrfs_assert_tree_write_locked(eb);
free_extent_buffer(eb);
cur_bit += (fs_info->nodesize >> fs_info->sectorsize_bits);
@ -1125,7 +1125,7 @@ void btrfs_clean_tree_block(struct extent_buffer *buf)
struct btrfs_fs_info *fs_info = buf->fs_info;
if (btrfs_header_generation(buf) ==
fs_info->running_transaction->transid) {
btrfs_assert_tree_locked(buf);
btrfs_assert_tree_write_locked(buf);
if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
@ -4481,7 +4481,7 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &buf->bflags)))
return;
#endif
btrfs_assert_tree_locked(buf);
btrfs_assert_tree_write_locked(buf);
if (transid != fs_info->generation)
WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, found %llu running %llu\n",
buf->start, transid, fs_info->generation);