[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>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index fbb4a6aa1583..2483d8741060 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -649,6 +649,10 @@ static int gfs2_write_begin(struct file *file, struct address_space *mapping,
 
         if (alloc_required) {
                 al = gfs2_alloc_get(ip);
+                if (!al) {
+                        error = -ENOMEM;
+                        goto out_unlock;
+                }
 
                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
                 if (error)