btrfs: don't clear qgroup reserved bit in release_folio

commit a86805504b88f636a6458520d85afdf0634e3c6b upstream.

The EXTENT_QGROUP_RESERVED bit is used to "lock" regions of the file for
duplicate reservations. That is two writes to that range in one
transaction shouldn't create two reservations, as the reservation will
only be freed once when the write finally goes down. Therefore, it is
never OK to clear that bit without freeing the associated qgroup
reserve. At this point, we don't want to be freeing the reserve, so mask
off the bit.

CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 1530df8..03c10e0 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2303,7 +2303,8 @@ static int try_release_extent_state(struct extent_io_tree *tree,
                ret = 0;
        } else {
                u32 clear_bits = ~(EXTENT_LOCKED | EXTENT_NODATASUM |
-                                  EXTENT_DELALLOC_NEW | EXTENT_CTLBITS);
+                                  EXTENT_DELALLOC_NEW | EXTENT_CTLBITS |
+                                  EXTENT_QGROUP_RESERVED);
 
                /*
                 * At this point we can safely clear everything except the