Commit 9f9bc034 authored by Brian Foster's avatar Brian Foster Committed by Darrick J. Wong
Browse files

xfs: update fork seq counter on data fork changes 



The sequence counter in the xfs_ifork structure is only updated on
COW forks. This is because the counter is currently only used to
optimize out repetitive COW fork checks at writeback time.

Tweak the extent code to update the seq counter regardless of the
fork type in preparation for using this counter on data forks as
well.

Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAllison Henderson <allison.henderson@oracle.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent d519da41

fs/xfs/libxfs/xfs_iext_tree.c

+6 −7
Original line number Diff line number Diff line
@@ -614,15 +614,14 @@ xfs_iext_realloc_root( 
}



/*

 * Increment the sequence counter if we are on a COW fork.  This allows

 * the writeback code to skip looking for a COW extent if the COW fork

 * hasn't changed.  We use WRITE_ONCE here to ensure the update to the

 * sequence counter is seen before the modifications to the extent

 * tree itself take effect.

 * Increment the sequence counter on extent tree changes. If we are on a COW

 * fork, this allows the writeback code to skip looking for a COW extent if the

 * COW fork hasn't changed. We use WRITE_ONCE here to ensure the update to the

 * sequence counter is seen before the modifications to the extent tree itself

 * take effect.

 */

static inline void xfs_iext_inc_seq(struct xfs_ifork *ifp, int state)

{

	if (state & BMAP_COWFORK)

	WRITE_ONCE(ifp->if_seq, READ_ONCE(ifp->if_seq) + 1);

}

fs/xfs/libxfs/xfs_inode_fork.h

+1 −1
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ struct xfs_dinode; 
 */

struct xfs_ifork {

	int			if_bytes;	/* bytes in if_u1 */

	unsigned int		if_seq;		/* cow fork mod counter */

	unsigned int		if_seq;		/* fork mod counter */

	struct xfs_btree_block	*if_broot;	/* file's incore btree root */

	short			if_broot_bytes;	/* bytes allocated for root */

	unsigned char		if_flags;	/* per-fork flags */

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