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>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index ea100eb..43af5a6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4560,36 +4560,37 @@
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
+ * removed the eb from the radix tree, so we could race
+ * and have this page now attached to the new eb. So
+ * only clear page_private if it's still connected to
+ * this eb.
+ */
+ if (PagePrivate(page) &&
+ page->private == (unsigned long)eb) {
+ BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
+ BUG_ON(PageDirty(page));
+ BUG_ON(PageWriteback(page));
/*
- * We do this since we'll remove the pages after we've
- * removed the eb from the radix tree, so we could race
- * and have this page now attached to the new eb. So
- * only clear page_private if it's still connected to
- * this eb.
+ * We need to make sure we haven't be attached
+ * to a new eb.
*/
- if (PagePrivate(page) &&
- page->private == (unsigned long)eb) {
- BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
- BUG_ON(PageDirty(page));
- BUG_ON(PageWriteback(page));
- /*
- * We need to make sure we haven't be attached
- * to a new eb.
- */
- ClearPagePrivate(page);
- set_page_private(page, 0);
- /* One for the page private */
- page_cache_release(page);
- }
- spin_unlock(&page->mapping->private_lock);
-
- }
- if (page) {
- /* One for when we alloced the page */
+ ClearPagePrivate(page);
+ set_page_private(page, 0);
+ /* One for the page private */
page_cache_release(page);
}
+
+ if (mapped)
+ spin_unlock(&page->mapping->private_lock);
+
+ /* One for when we alloced the page */
+ page_cache_release(page);
} while (index != 0);
}