xfs: relax is_reflink_inode assert in xfs_reflink_find_cow_mapping

We don't hold the ilock through the entire sequence of xfs_writepage_map
-> xfs_map_cow -> xfs_reflink_find_cow_mapping.  This means that we can
race with another thread that is trying to clear the inode reflink flag,
with the result that the flag is set for the xfs_map_cow check but
cleared before we get to the assert in find_cow_mapping.  When this
happens, we blow the assert even though everything is fine.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2017-12-10 18:03:55 -08:00
parent 5c989a0ee0
commit 73353f486c

View File

@ -490,8 +490,9 @@ xfs_reflink_find_cow_mapping(
struct xfs_iext_cursor icur;
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
ASSERT(xfs_is_reflink_inode(ip));
if (!xfs_is_reflink_inode(ip))
return false;
offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got))
return false;