From e55a0de185726ca43e8a31d363ad73c4f0a6770b Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 27 Sep 2021 15:22:05 +0800 Subject: btrfs: rework page locking in __extent_writepage() Pages passed to __extent_writepage() are always locked, but they may be locked by different functions. There are two types of locked page for __extent_writepage(): - Page locked by plain lock_page() It should not have any subpage::writers count. Can be unlocked by unlock_page(). This is the most common locked page for __extent_writepage() called inside extent_write_cache_pages() or extent_write_full_page(). Rarer cases include the @locked_page from extent_write_locked_range(). - Page locked by lock_delalloc_pages() There is only one caller, all pages except @locked_page for extent_write_locked_range(). In this case, we have to call subpage helper to handle the case. So here we introduce a helper, btrfs_page_unlock_writer(), to allow __extent_writepage() to unlock different locked pages. And since for all other callers of __extent_writepage() their pages are ensured to be locked by lock_page(), also add an extra check for epd::extent_locked to unlock such pages directly. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/subpage.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/btrfs/subpage.h') diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h index 46224f959c34..7accb5c40d33 100644 --- a/fs/btrfs/subpage.h +++ b/fs/btrfs/subpage.h @@ -150,5 +150,7 @@ bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info, void btrfs_page_assert_not_dirty(const struct btrfs_fs_info *fs_info, struct page *page); +void btrfs_page_unlock_writer(struct btrfs_fs_info *fs_info, struct page *page, + u64 start, u32 len); #endif -- cgit v1.2.3