[PATCH] knfsd: calls to break_lease in nfsd should be O_NONBLOCKing

If we would block, we return "err-jukebox" for nfsv3, or just drop the request
for v2.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfsproc.c

@@ -586,6 +586,7 @@ nfserrno (int errno)
 		{ nfserr_dquot, -EDQUOT },
 #endif
 		{ nfserr_stale, -ESTALE },
+		{ nfserr_jukebox, -EWOULDBLOCK },
 		{ nfserr_jukebox, -ETIMEDOUT },
 		{ nfserr_dropit, -EAGAIN },
 		{ nfserr_dropit, -ENOMEM },

fs/nfsd/nfssvc.c

@@ -328,6 +328,8 @@ nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp)
 
 	/* Now call the procedure handler, and encode NFS status. */
 	nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
+	if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
+		nfserr = nfserr_dropit;
 	if (nfserr == nfserr_dropit) {
 		dprintk("nfsd: Dropping request due to malloc failure!\n");
 		nfsd_cache_update(rqstp, RC_NOCACHE, NULL);

fs/nfsd/vfs.c

@@ -303,8 +303,8 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 		 * If we are changing the size of the file, then
 		 * we need to break all leases.
 		 */
-		err = break_lease(inode, FMODE_WRITE);
-		if (err)
+		err = break_lease(inode, FMODE_WRITE | O_NONBLOCK);
+		if (err) /* ENOMEM or EWOULDBLOCK */
 			goto out_nfserr;
 
 		err = get_write_access(inode);
@@ -669,8 +669,8 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	 * Check to see if there are any leases on this file.
 	 * This may block while leases are broken.
 	 */
-	err = break_lease(inode, (access & MAY_WRITE) ? FMODE_WRITE : 0);
-	if (err)
+	err = break_lease(inode, O_NONBLOCK | ((access & MAY_WRITE) ? FMODE_WRITE : 0));
+	if (err) /* NOMEM or WOULDBLOCK */
 		goto out_nfserr;
 
 	if (access & MAY_WRITE) {