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Commit 5a65503f authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4.1: Deal with wraparound issues when updating the layout stateid 



...and add a helper function.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 038d6493

fs/nfs/pnfs.c

+10 −1
Original line number Original line Diff line number Diff line
@@ -549,6 +549,15 @@ pnfs_destroy_all_layouts(struct nfs_client *clp) 
	}

	}

}

}





/*

 * Compare 2 layout stateid sequence ids, to see which is newer,

 * taking into account wraparound issues.

 */

static bool pnfs_seqid_is_newer(u32 s1, u32 s2)

{

	return (s32)s1 - (s32)s2 > 0;

}



/* update lo->plh_stateid with new if is more recent */

/* update lo->plh_stateid with new if is more recent */

void

void

pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,

pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
@@ -558,7 +567,7 @@ pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new, 




	oldseq = be32_to_cpu(lo->plh_stateid.seqid);

	oldseq = be32_to_cpu(lo->plh_stateid.seqid);

	newseq = be32_to_cpu(new->seqid);

	newseq = be32_to_cpu(new->seqid);

	if (list_empty(&lo->plh_segs) || (int)(newseq - oldseq) > 0) {

	if (list_empty(&lo->plh_segs) || pnfs_seqid_is_newer(newseq, oldseq)) {

		nfs4_stateid_copy(&lo->plh_stateid, new);

		nfs4_stateid_copy(&lo->plh_stateid, new);

		if (update_barrier) {

		if (update_barrier) {

			u32 new_barrier = be32_to_cpu(new->seqid);

			u32 new_barrier = be32_to_cpu(new->seqid);