Commit 9bf87482 authored by Peng Tao's avatar Peng Tao Committed by Tom Haynes
Browse files

nfs41: serialize first layoutget of a file 



Per RFC 5661 Errata 3208:
| A client MAY always forget its layout state and associated
| layout stateid at any time (See also section 12.5.5.1).
| In such case, the client MUST use a non-layout stateid for the next
| LAYOUTGET operation. This will signal the server that the client has
| no more layouts on the file and its respective layout state can be
| released before issuing a new layout in response to LAYOUTGET.

In order to make such a signal unique to server, client needs to serialize
all layoutgets using non-layout stateid. We implement this by serializing
layoutgets when client has no layout segments at hand.

Signed-off-by: default avatarPeng Tao <tao.peng@primarydata.com>
Signed-off-by: default avatarTom Haynes <Thomas.Haynes@primarydata.com>
parent abb9a007

fs/nfs/pnfs.c

+31 −4
Original line number Diff line number Diff line
@@ -1288,6 +1288,7 @@ pnfs_update_layout(struct inode *ino, 
	struct nfs_client *clp = server->nfs_client;

	struct pnfs_layout_hdr *lo;

	struct pnfs_layout_segment *lseg = NULL;

	bool first;



	if (!pnfs_enabled_sb(NFS_SERVER(ino)))

		goto out;
@@ -1295,6 +1296,8 @@ pnfs_update_layout(struct inode *ino, 
	if (pnfs_within_mdsthreshold(ctx, ino, iomode))

		goto out;



lookup_again:

	first = false;

	spin_lock(&ino->i_lock);

	lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);

	if (lo == NULL) {
@@ -1312,10 +1315,27 @@ pnfs_update_layout(struct inode *ino, 
	if (pnfs_layout_io_test_failed(lo, iomode))

		goto out_unlock;



	/* Check to see if the layout for the given range already exists */

	first = list_empty(&lo->plh_segs);

	if (first) {

		/* The first layoutget for the file. Need to serialize per

		 * RFC 5661 Errata 3208.

		 */

		if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET,

				     &lo->plh_flags)) {

			spin_unlock(&ino->i_lock);

			wait_on_bit(&lo->plh_flags, NFS_LAYOUT_FIRST_LAYOUTGET,

				    TASK_UNINTERRUPTIBLE);

			pnfs_put_layout_hdr(lo);

			goto lookup_again;

		}

	} else {

		/* Check to see if the layout for the given range

		 * already exists

		 */

		lseg = pnfs_find_lseg(lo, &arg);

		if (lseg)

			goto out_unlock;

	}



	if (pnfs_layoutgets_blocked(lo, 0))

		goto out_unlock;
@@ -1343,6 +1363,13 @@ pnfs_update_layout(struct inode *ino, 
	lseg = send_layoutget(lo, ctx, &arg, gfp_flags);

	atomic_dec(&lo->plh_outstanding);

out_put_layout_hdr:

	if (first) {

		unsigned long *bitlock = &lo->plh_flags;



		clear_bit_unlock(NFS_LAYOUT_FIRST_LAYOUTGET, bitlock);

		smp_mb__after_atomic();

		wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET);

	}

	pnfs_put_layout_hdr(lo);

out:

	dprintk("%s: inode %s/%llu pNFS layout segment %s for "

fs/nfs/pnfs.h

+1 −0
Original line number Diff line number Diff line
@@ -95,6 +95,7 @@ enum { 
	NFS_LAYOUT_ROC,			/* some lseg had roc bit set */

	NFS_LAYOUT_RETURN,		/* Return this layout ASAP */

	NFS_LAYOUT_INVALID_STID,	/* layout stateid id is invalid */

	NFS_LAYOUT_FIRST_LAYOUTGET,	/* Serialize first layoutget */

};



enum layoutdriver_policy_flags {

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