diff mbox series

[v2,10/19] btrfs: add assert_spin_locked() for attach_extent_buffer_page()

Message ID 20200915053532.63279-11-wqu@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: add read-only support for subpage sector size | expand

Commit Message

Qu Wenruo Sept. 15, 2020, 5:35 a.m. UTC 
When calling attach_extent_buffer_page(), either we're attaching
anonymous pages, called from btrfs_clone_extent_buffer().

Or we're attaching btree_inode pages, called from alloc_extent_buffer().

For the later case, we should have page->mapping->private_lock hold to
avoid race modifying page->private.

Add assert_spin_locked() if we're calling from alloc_extent_buffer().

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/extent_io.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Johannes Thumshirn Sept. 15, 2020, 8:52 a.m. UTC | #1 
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
diff mbox series

Patch

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index ba9cc864d9c0..9d4a81997738 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3096,6 +3096,15 @@  static int submit_extent_page(unsigned int opf,
 static void attach_extent_buffer_page(struct extent_buffer *eb,
 				      struct page *page)
 {
+	/*
+	 * If the page is mapped to btree inode, we should hold the private
+	 * lock to prevent race.
+	 * For cloned or dummy extent buffers, their pages are not mapped and
+	 * will not race with any other ebs.
+	 */
+	if (page->mapping)
+		assert_spin_locked(&page->mapping->private_lock);
+
 	if (!PagePrivate(page))
 		attach_page_private(page, eb);
 	else