[PATCH] jfs: Add missing NULL pointer check in __get_metapage

[Juerg Haefliger]

alloc_metapage can return a NULL pointer so check for that. And also emit
an error message if that happens.

Signed-off-by: Juerg Haefliger <juerg.haefli...@canonical.com>
---
 fs/jfs/jfs_metapage.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 1c4b9ad4d7ab..00f21af66872 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -187,14 +187,18 @@ static inline struct metapage *alloc_metapage(gfp_t 
gfp_mask)
 {
        struct metapage *mp = mempool_alloc(metapage_mempool, gfp_mask);
 
-       if (mp) {
-               mp->lid = 0;
-               mp->lsn = 0;
-               mp->data = NULL;
-               mp->clsn = 0;
-               mp->log = NULL;
-               init_waitqueue_head(&mp->wait);
+       if (!mp) {
+               jfs_err("mempool_alloc failed!\n");
+               return NULL;
        }
+
+       mp->lid = 0;
+       mp->lsn = 0;
+       mp->data = NULL;
+       mp->clsn = 0;
+       mp->log = NULL;
+       init_waitqueue_head(&mp->wait);
+
        return mp;
 }
 
@@ -663,6 +667,8 @@ struct metapage *__get_metapage(struct inode *inode, 
unsigned long lblock,
        } else {
                INCREMENT(mpStat.pagealloc);
                mp = alloc_metapage(GFP_NOFS);
+               if (!mp)
+                       goto unlock;
                mp->page = page;
                mp->sb = inode->i_sb;
                mp->flag = 0;
-- 
2.14.1