Fix miscellaneous nfsd bugs, in NFSv4.1 callbacks, NFSv4.1

lock-notification callbacks, NFSv3 readdir encoding, and the
 cache/upcall code.
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Merge tag 'nfsd-5.1-1' of git://linux-nfs.org/~bfields/linux

Pull nfsd bugfixes from Bruce Fields:
 "Fix miscellaneous nfsd bugs, in NFSv4.1 callbacks, NFSv4.1
  lock-notification callbacks, NFSv3 readdir encoding, and the
  cache/upcall code"

* tag 'nfsd-5.1-1' of git://linux-nfs.org/~bfields/linux:
  nfsd: wake blocked file lock waiters before sending callback
  nfsd: wake waiters blocked on file_lock before deleting it
  nfsd: Don't release the callback slot unless it was actually held
  nfsd/nfsd3_proc_readdir: fix buffer count and page pointers
  sunrpc: don't mark uninitialised items as VALID.

fs/nfsd/nfs3proc.c

@@ -442,7 +442,9 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 	struct nfsd3_readdirargs *argp = rqstp->rq_argp;
 	struct nfsd3_readdirres  *resp = rqstp->rq_resp;
 	__be32		nfserr;
-	int		count;
+	int		count = 0;
+	struct page	**p;
+	caddr_t		page_addr = NULL;
 
 	dprintk("nfsd: READDIR(3)  %s %d bytes at %d\n",
 				SVCFH_fmt(&argp->fh),
@@ -462,7 +464,18 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 	nfserr = nfsd_readdir(rqstp, &resp->fh, (loff_t*) &argp->cookie, 
 					&resp->common, nfs3svc_encode_entry);
 	memcpy(resp->verf, argp->verf, 8);
-	resp->count = resp->buffer - argp->buffer;
+	count = 0;
+	for (p = rqstp->rq_respages + 1; p < rqstp->rq_next_page; p++) {
+		page_addr = page_address(*p);
+
+		if (((caddr_t)resp->buffer >= page_addr) &&
+		    ((caddr_t)resp->buffer < page_addr + PAGE_SIZE)) {
+			count += (caddr_t)resp->buffer - page_addr;
+			break;
+		}
+		count += PAGE_SIZE;
+	}
+	resp->count = count >> 2;
 	if (resp->offset) {
 		loff_t offset = argp->cookie;
 

fs/nfsd/nfs3xdr.c

@@ -573,6 +573,7 @@ int
 nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_readdirargs *args = rqstp->rq_argp;
+	int len;
 	u32 max_blocksize = svc_max_payload(rqstp);
 
 	p = decode_fh(p, &args->fh);
@@ -582,8 +583,14 @@ nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
 	args->verf   = p; p += 2;
 	args->dircount = ~0;
 	args->count  = ntohl(*p++);
-	args->count  = min_t(u32, args->count, max_blocksize);
-	args->buffer = page_address(*(rqstp->rq_next_page++));
+	len = args->count  = min_t(u32, args->count, max_blocksize);
+
+	while (len > 0) {
+		struct page *p = *(rqstp->rq_next_page++);
+		if (!args->buffer)
+			args->buffer = page_address(p);
+		len -= PAGE_SIZE;
+	}
 
 	return xdr_argsize_check(rqstp, p);
 }

fs/nfsd/nfs4callback.c

@@ -1010,8 +1010,9 @@ static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 	cb->cb_seq_status = 1;
 	cb->cb_status = 0;
 	if (minorversion) {
-		if (!nfsd41_cb_get_slot(clp, task))
+		if (!cb->cb_holds_slot && !nfsd41_cb_get_slot(clp, task))
 			return;
+		cb->cb_holds_slot = true;
 	}
 	rpc_call_start(task);
 }
@@ -1038,6 +1039,9 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
 		return true;
 	}
 
+	if (!cb->cb_holds_slot)
+		goto need_restart;
+
 	switch (cb->cb_seq_status) {
 	case 0:
 		/*
@@ -1076,6 +1080,7 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
 			cb->cb_seq_status);
 	}
 
+	cb->cb_holds_slot = false;
 	clear_bit(0, &clp->cl_cb_slot_busy);
 	rpc_wake_up_next(&clp->cl_cb_waitq);
 	dprintk("%s: freed slot, new seqid=%d\n", __func__,
@@ -1283,6 +1288,7 @@ void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
 	cb->cb_seq_status = 1;
 	cb->cb_status = 0;
 	cb->cb_need_restart = false;
+	cb->cb_holds_slot = false;
 }
 
 void nfsd4_run_cb(struct nfsd4_callback *cb)

fs/nfsd/nfs4state.c

@@ -265,6 +265,7 @@ find_or_allocate_block(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
 static void
 free_blocked_lock(struct nfsd4_blocked_lock *nbl)
 {
+	locks_delete_block(&nbl->nbl_lock);
 	locks_release_private(&nbl->nbl_lock);
 	kfree(nbl);
 }
@@ -293,11 +294,18 @@ remove_blocked_locks(struct nfs4_lockowner *lo)
 		nbl = list_first_entry(&reaplist, struct nfsd4_blocked_lock,
 					nbl_lru);
 		list_del_init(&nbl->nbl_lru);
-		locks_delete_block(&nbl->nbl_lock);
 		free_blocked_lock(nbl);
 	}
 }
 
+static void
+nfsd4_cb_notify_lock_prepare(struct nfsd4_callback *cb)
+{
+	struct nfsd4_blocked_lock	*nbl = container_of(cb,
+						struct nfsd4_blocked_lock, nbl_cb);
+	locks_delete_block(&nbl->nbl_lock);
+}
+
 static int
 nfsd4_cb_notify_lock_done(struct nfsd4_callback *cb, struct rpc_task *task)
 {
@@ -325,6 +333,7 @@ nfsd4_cb_notify_lock_release(struct nfsd4_callback *cb)
 }
 
 static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = {
+	.prepare	= nfsd4_cb_notify_lock_prepare,
 	.done		= nfsd4_cb_notify_lock_done,
 	.release	= nfsd4_cb_notify_lock_release,
 };
@@ -4863,7 +4872,6 @@ nfs4_laundromat(struct nfsd_net *nn)
 		nbl = list_first_entry(&reaplist,
 					struct nfsd4_blocked_lock, nbl_lru);
 		list_del_init(&nbl->nbl_lru);
-		locks_delete_block(&nbl->nbl_lock);
 		free_blocked_lock(nbl);
 	}
 out:

fs/nfsd/state.h

@@ -70,6 +70,7 @@ struct nfsd4_callback {
 	int cb_seq_status;
 	int cb_status;
 	bool cb_need_restart;
+	bool cb_holds_slot;
 };
 
 struct nfsd4_callback_ops {

net/sunrpc/cache.c

@@ -54,6 +54,7 @@ static void cache_init(struct cache_head *h, struct cache_detail *detail)
 	h->last_refresh = now;
 }
 
+static inline int cache_is_valid(struct cache_head *h);
 static void cache_fresh_locked(struct cache_head *head, time_t expiry,
 				struct cache_detail *detail);
 static void cache_fresh_unlocked(struct cache_head *head,
@@ -105,6 +106,8 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
 			if (cache_is_expired(detail, tmp)) {
 				hlist_del_init_rcu(&tmp->cache_list);
 				detail->entries --;
+				if (cache_is_valid(tmp) == -EAGAIN)
+					set_bit(CACHE_NEGATIVE, &tmp->flags);
 				cache_fresh_locked(tmp, 0, detail);
 				freeme = tmp;
 				break;