diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 0902d54de76e..b0fa996be51f 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5814,28 +5814,51 @@ void free_extent_buffer_stale(struct extent_buffer *eb) release_extent_buffer(eb); } +static void btree_clear_page_dirty(struct page *page) +{ + ASSERT(PageDirty(page)); + ASSERT(PageLocked(page)); + clear_page_dirty_for_io(page); + xa_lock_irq(&page->mapping->i_pages); + if (!PageDirty(page)) + __xa_clear_mark(&page->mapping->i_pages, + page_index(page), PAGECACHE_TAG_DIRTY); + xa_unlock_irq(&page->mapping->i_pages); +} + +static void clear_subpage_extent_buffer_dirty(const struct extent_buffer *eb) +{ + struct btrfs_fs_info *fs_info = eb->fs_info; + struct page *page = eb->pages[0]; + bool last; + + /* btree_clear_page_dirty() needs page locked */ + lock_page(page); + last = btrfs_subpage_clear_and_test_dirty(fs_info, page, eb->start, + eb->len); + if (last) + btree_clear_page_dirty(page); + unlock_page(page); + WARN_ON(atomic_read(&eb->refs) == 0); +} + void clear_extent_buffer_dirty(const struct extent_buffer *eb) { int i; int num_pages; struct page *page; + if (eb->fs_info->sectorsize < PAGE_SIZE) + return clear_subpage_extent_buffer_dirty(eb); + num_pages = num_extent_pages(eb); for (i = 0; i < num_pages; i++) { page = eb->pages[i]; if (!PageDirty(page)) continue; - lock_page(page); - WARN_ON(!PagePrivate(page)); - - clear_page_dirty_for_io(page); - xa_lock_irq(&page->mapping->i_pages); - if (!PageDirty(page)) - __xa_clear_mark(&page->mapping->i_pages, - page_index(page), PAGECACHE_TAG_DIRTY); - xa_unlock_irq(&page->mapping->i_pages); + btree_clear_page_dirty(page); ClearPageError(page); unlock_page(page); } @@ -5856,10 +5879,28 @@ bool set_extent_buffer_dirty(struct extent_buffer *eb) WARN_ON(atomic_read(&eb->refs) == 0); WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)); - if (!was_dirty) - for (i = 0; i < num_pages; i++) - set_page_dirty(eb->pages[i]); + if (!was_dirty) { + bool subpage = eb->fs_info->sectorsize < PAGE_SIZE; + /* + * For subpage case, we can have other extent buffers in the + * same page, and in clear_subpage_extent_buffer_dirty() we + * have to clear page dirty without subpage lock held. + * This can cause race where our page gets dirty cleared after + * we just set it. + * + * Thankfully, clear_subpage_extent_buffer_dirty() has locked + * its page for other reasons, we can use page lock to prevent + * the above race. + */ + if (subpage) + lock_page(eb->pages[0]); + for (i = 0; i < num_pages; i++) + btrfs_page_set_dirty(eb->fs_info, eb->pages[i], + eb->start, eb->len); + if (subpage) + unlock_page(eb->pages[0]); + } #ifdef CONFIG_BTRFS_DEBUG for (i = 0; i < num_pages; i++) ASSERT(PageDirty(eb->pages[i]));