xfs: don't be so eager to clear the cowblocks tag on truncate (363e59ba) · Commits · 戴 / test

Currently, xfs_itruncate_extents clears the cowblocks tag if i_cnextents is zero. This is wrong, since i_cnextents only tracks real extents in the CoW fork, which means that we could have some delayed CoW reservations still in there that will now never get cleaned. Fix a further bug where we /don't/ clear the reflink iflag if there are any attribute blocks -- really, it's only safe to clear the reflink flag if there are no data fork extents and no cow fork extents. Found by adding clonerange to fsstress in xfs/017. Signed-off-by:

Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by:

Dave Chinner <dchinner@redhat.com> Reviewed-by:

Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_inode.c

+19 −9

Original line number	Diff line number	Diff line
		@@ -1487,6 +1487,24 @@ xfs_link(
		return error;
		}

		/* Clear the reflink flag and the cowblocks tag if possible. */
		static void
		xfs_itruncate_clear_reflink_flags(
		struct xfs_inode *ip)
		{
		struct xfs_ifork *dfork;
		struct xfs_ifork *cfork;

		if (!xfs_is_reflink_inode(ip))
		return;
		dfork = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
		cfork = XFS_IFORK_PTR(ip, XFS_COW_FORK);
		if (dfork->if_bytes == 0 && cfork->if_bytes == 0)
		ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
		if (cfork->if_bytes == 0)
		xfs_inode_clear_cowblocks_tag(ip);
		}

		/*
		* Free up the underlying blocks past new_size. The new size must be smaller
		* than the current size. This routine can be used both for the attribute and
		@@ -1583,15 +1601,7 @@ xfs_itruncate_extents(
		if (error)
		goto out;

		/*
		* Clear the reflink flag if there are no data fork blocks and
		* there are no extents staged in the cow fork.
		*/
		if (xfs_is_reflink_inode(ip) && ip->i_cnextents == 0) {
		if (ip->i_d.di_nblocks == 0)
		ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
		xfs_inode_clear_cowblocks_tag(ip);
		}
		xfs_itruncate_clear_reflink_flags(ip);

		/*
		* Always re-log the inode so that our permanent transaction can keep

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