[GFS2] possible null pointer dereference fixup

gfs2_alloc_get may fail so we have to check it to prevent
NULL pointer dereference.

Signed-off-by: Cyrill Gorcunov <gorcunov@gamil.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 92ea9af..dcae2aa 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -351,6 +351,8 @@
 	}
 
 	al = gfs2_alloc_get(ip);
+	if (!al)
+		return -ENOMEM;
 
 	error = gfs2_quota_hold(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 	if (error)
@@ -825,7 +827,8 @@
 	int error;
 
 	munge_mode_uid_gid(dip, &mode, &uid, &gid);
-	gfs2_alloc_get(dip);
+	if (!gfs2_alloc_get(dip))
+		return -ENOMEM;
 
 	error = gfs2_quota_lock(dip, uid, gid);
 	if (error)
@@ -860,6 +863,8 @@
 	int error;
 
 	al = gfs2_alloc_get(dip);
+	if (!al)
+		return -ENOMEM;
 
 	error = gfs2_quota_lock(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 	if (error)