Commit 73353f48 authored Dec 10, 2017 by Darrick J. Wong

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>

parent 5c989a0e

fs/xfs/xfs_reflink.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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;