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btrfs: assert page mapping lock in attach_extent_buffer_page

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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 latter case, we should hold page->mapping->private_lock to avoid
parallel changes to page->private.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2020-10-21 14:25:02 +08:00 committed by David Sterba
parent bbb86a3717
commit 0d01e247a0
1 changed files with 9 additions and 0 deletions
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9
fs/btrfs/extent_io.c
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@ -3102,6 +3102,15 @@ static int submit_extent_page(unsigned int opf,
static void attach_extent_buffer_page(struct extent_buffer *eb, static void attach_extent_buffer_page(struct extent_buffer *eb,
struct page *page) 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)
lockdep_assert_held(&page->mapping->private_lock);
if (!PagePrivate(page)) if (!PagePrivate(page))
attach_page_private(page, eb); attach_page_private(page, eb);
else else