Commit 5d2361db authored Feb 09, 2015 by Forrest Liu Committed by Chris Mason Apr 29, 2015

Btrfs: btrfs_release_extent_buffer_page didn't free pages of dummy extent



btrfs_release_extent_buffer_page() can't handle dummy extent that
allocated by btrfs_clone_extent_buffer() properly. That is because
reference count of pages that allocated by btrfs_clone_extent_buffer()
was 2, 1 by alloc_page(), and another by attach_extent_buffer_page().

Running following command repeatly can check this memory leak problem

    btrfs inspect-internal inode-resolve 256 /mnt/btrfs

Signed-off-by: Chien-Kuan Yeh <ckya@synology.com>
Signed-off-by: Forrest Liu <forrestl@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>

parent 6e17d30b

fs/btrfs/extent_io.c

+26 −25

Original line number	Diff line number	Diff line
		@@ -4560,7 +4560,9 @@ static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
		do {
		index--;
		page = eb->pages[index];
		if (page && mapped) {
		if (!page)
		continue;
		if (mapped)
		spin_lock(&page->mapping->private_lock);
		/*
		* We do this since we'll remove the pages after we've
		@@ -4583,13 +4585,12 @@ static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
		/* One for the page private */
		page_cache_release(page);
		}

		if (mapped)
		spin_unlock(&page->mapping->private_lock);

		}
		if (page) {
		/* One for when we alloced the page */
		page_cache_release(page);
		}
		} while (index != 0);
		}