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Commit 8c7424cf authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd4: don't try to encode conflicting owner if low on space 



I ran into this corner case in testing: in theory clients can provide
state owners up to 1024 bytes long.  In the sessions case there might be
a risk of this pushing us over the DRC slot size.

The conflicting owner isn't really that important, so let's humor a
client that provides a small maxresponsize_cached by allowing ourselves
to return without the conflicting owner instead of outright failing the
operation.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent f5236013

fs/nfsd/nfs4proc.c

+2 −1
Original line number Diff line number Diff line
@@ -1432,7 +1432,8 @@ nfsd4_proc_compound(struct svc_rqst *rqstp, 
#define op_encode_change_info_maxsz	(5)

#define nfs4_fattr_bitmap_maxsz		(4)



#define op_encode_lockowner_maxsz	(1 + XDR_QUADLEN(IDMAP_NAMESZ))

/* We'll fall back on returning no lockowner if run out of space: */

#define op_encode_lockowner_maxsz	(0)

#define op_encode_lock_denied_maxsz	(8 + op_encode_lockowner_maxsz)



#define nfs4_owner_maxsz		(1 + XDR_QUADLEN(IDMAP_NAMESZ))

fs/nfsd/nfs4xdr.c

+13 −3
Original line number Diff line number Diff line
@@ -2878,9 +2878,20 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld) 
	struct xdr_netobj *conf = &ld->ld_owner;

	__be32 *p;



again:

	p = xdr_reserve_space(xdr, 32 + XDR_LEN(conf->len));

	if (!p)

	if (!p) {

		/*

		 * Don't fail to return the result just because we can't

		 * return the conflicting open:

		 */

		if (conf->len) {

			conf->len = 0;

			conf->data = NULL;

			goto again;

		}

		return nfserr_resource;

	}

	WRITE64(ld->ld_start);

	WRITE64(ld->ld_length);

	WRITE32(ld->ld_type);
@@ -2888,7 +2899,6 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld) 
		WRITEMEM(&ld->ld_clientid, 8);

		WRITE32(conf->len);

		WRITEMEM(conf->data, conf->len);

		kfree(conf->data);

	}  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */

		WRITE64((u64)0); /* clientid */

		WRITE32(0); /* length of owner name */
@@ -2905,7 +2915,7 @@ nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lo 
		nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid);

	else if (nfserr == nfserr_denied)

		nfserr = nfsd4_encode_lock_denied(xdr, &lock->lk_denied);



	kfree(lock->lk_denied.ld_owner.data);

	return nfserr;

}