/proc/kcore: update stat.st_size after memory hotplug

After memory hotplug (or other events in future), kcore size can be
modified.

To update inode->i_size, we have to know inode/dentry but we can't get it
from inside /proc directly.  But considerinyg memory hotplug, kcore image
is updated only when it's opened.  Then, updating inode->i_size at open()
is enough.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 3d0485c361c7..56013371f9f3 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -546,6 +546,11 @@ static int open_kcore(struct inode *inode, struct file *filp)
                 return -EPERM;
         if (kcore_need_update)
                 kcore_update_ram();
+        if (i_size_read(inode) != proc_root_kcore->size) {
+                mutex_lock(&inode->i_mutex);
+                i_size_write(inode, proc_root_kcore->size);
+                mutex_unlock(&inode->i_mutex);
+        }
         return 0;
 }