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Commit ecebb80b authored by Trond Myklebust's avatar Trond Myklebust
Browse files

pNFS: Always update the layout barrier seqid on LAYOUTGET 



Currently, pnfs_set_layout_stateid() will update the layout sequence
id barrier only if the stateid itself is newer than the current
layout stateid. However in a situation where multiple LAYOUTGET calls
and a LAYOUTRETURN raced, it is entirely possible for one of the
LAYOUTGET to set the current stateid to something newer than the
LAYOUTRETURN that needs to set the barrier.

The fix is to allow the "update_barrier" flag to force a check as to
whether or not the barrier needs to be updated.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 13bede18

fs/nfs/pnfs.c

+14 −13
Original line number Diff line number Diff line
@@ -761,25 +761,26 @@ void 
pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,

			bool update_barrier)

{

	u32 oldseq, newseq, new_barrier;

	bool empty = !pnfs_layout_is_valid(lo);

	u32 oldseq, newseq, new_barrier = 0;

	bool invalid = !pnfs_layout_is_valid(lo);



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

	newseq = be32_to_cpu(new->seqid);

	if (empty || pnfs_seqid_is_newer(newseq, oldseq)) {

	if (invalid || pnfs_seqid_is_newer(newseq, oldseq)) {

		nfs4_stateid_copy(&lo->plh_stateid, new);

		if (update_barrier) {

			new_barrier = be32_to_cpu(new->seqid);

		} else {

			/* Because of wraparound, we want to keep the barrier

		/*

		 * Because of wraparound, we want to keep the barrier

		 * "close" to the current seqids.

		 */

		new_barrier = newseq - atomic_read(&lo->plh_outstanding);

	}

		if (empty || pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))

	if (update_barrier)

		new_barrier = be32_to_cpu(new->seqid);

	else if (new_barrier == 0)

		return;

	if (invalid || pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))

		lo->plh_barrier = new_barrier;

}

}



static bool

pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,