From 42f6f6b1b2dcc2ca10d31421d2dd6273851e012d Mon Sep 17 00:00:00 2001
From: Venkatesh Srinivas <me@endeavour.zapto.org>
Date: Tue, 24 Aug 2010 20:03:34 -0700
Subject: [PATCH] tmpfs: Allow kmalloc from M_TMPFSNAME zone to return NULL;
 handle null cases.

tmpfs now survives fsstress without panicing the system.
---
 sys/vfs/tmpfs/tmpfs_subr.c  | 17 +++++++++++++----
 sys/vfs/tmpfs/tmpfs_vnops.c |  7 ++++++-
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/sys/vfs/tmpfs/tmpfs_subr.c b/sys/vfs/tmpfs/tmpfs_subr.c
index 564c8b7b86..8f286e4161 100644
--- a/sys/vfs/tmpfs/tmpfs_subr.c
+++ b/sys/vfs/tmpfs/tmpfs_subr.c
@@ -126,6 +126,7 @@ tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
 	case VCHR:
 		rdev = makeudev(rmajor, rminor);
 		if (rdev == NOUDEV) {
+			objcache_put(tmp->tm_node_pool, nnode);
 			return(EINVAL);
 		}
 		nnode->tn_rdev = rdev;
@@ -155,7 +156,11 @@ tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
 	case VLNK:
 		nnode->tn_size = strlen(target);
 		nnode->tn_link = kmalloc(nnode->tn_size + 1, M_TMPFSNAME,
-					 M_WAITOK);
+					 M_WAITOK | M_NULLOK);
+		if (nnode->tn_link == NULL) {
+			objcache_put(tmp->tm_node_pool, nnode);
+			return (ENOSPC);
+		}
 		bcopy(target, nnode->tn_link, nnode->tn_size);
 		nnode->tn_link[nnode->tn_size] = '\0';
 		break;
@@ -315,9 +320,13 @@ tmpfs_alloc_dirent(struct tmpfs_mount *tmp, struct tmpfs_node *node,
 {
 	struct tmpfs_dirent *nde;
 
-
-	nde = (struct tmpfs_dirent *)objcache_get(tmp->tm_dirent_pool, M_WAITOK);
-	nde->td_name = kmalloc(len + 1, M_TMPFSNAME, M_WAITOK);
+	nde = objcache_get(tmp->tm_dirent_pool, M_WAITOK);
+	nde->td_name = kmalloc(len + 1, M_TMPFSNAME, M_WAITOK | M_NULLOK);
+	if (nde->td_name == NULL) {
+		objcache_put(tmp->tm_dirent_pool, nde);
+		*de = NULL;
+		return (ENOSPC);
+	}
 	nde->td_namelen = len;
 	bcopy(name, nde->td_name, len);
 	nde->td_name[len] = '\0';
diff --git a/sys/vfs/tmpfs/tmpfs_vnops.c b/sys/vfs/tmpfs/tmpfs_vnops.c
index a582618524..9dfae260d1 100644
--- a/sys/vfs/tmpfs/tmpfs_vnops.c
+++ b/sys/vfs/tmpfs/tmpfs_vnops.c
@@ -937,7 +937,12 @@ tmpfs_nrename(struct vop_nrename_args *v)
 	 */
 	if (fncp->nc_nlen != tncp->nc_nlen ||
 	    bcmp(fncp->nc_name, tncp->nc_name, fncp->nc_nlen) != 0) {
-		newname = kmalloc(tncp->nc_nlen + 1, M_TMPFSNAME, M_WAITOK);
+		newname = kmalloc(tncp->nc_nlen + 1, M_TMPFSNAME, 
+				  M_WAITOK | M_NULLOK);
+		if (newname == NULL) {
+			error = ENOSPC;
+			goto out_locked;
+		}
 		bcopy(tncp->nc_name, newname, tncp->nc_nlen);
 		newname[tncp->nc_nlen] = '\0';
 	} else {
-- 
2.41.0