[CIFS] lock inode open file list in close in case racing with open

Harmless since it only protected turning off caching for the
inode, but cleaner to lock around this in case we have a close
racing with open.

Signed-off-by: Shaggy <shaggy@us.ibm.com>
CC: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index b1807fd1ac40..792549193865 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -545,6 +545,7 @@ int cifs_close(struct inode *inode, struct file *file)
         } else
                 rc = -EBADF;
 
+        read_lock(&GlobalSMBSeslock);
         if (list_empty(&(CIFS_I(inode)->openFileList))) {
                 cFYI(1, ("closing last open instance for inode %p", inode));
                 /* if the file is not open we do not know if we can cache info
@@ -552,6 +553,7 @@ int cifs_close(struct inode *inode, struct file *file)
                 CIFS_I(inode)->clientCanCacheRead = FALSE;
                 CIFS_I(inode)->clientCanCacheAll  = FALSE;
         }
+        read_unlock(&GlobalSMBSeslock);
         if ((rc == 0) && CIFS_I(inode)->write_behind_rc)
                 rc = CIFS_I(inode)->write_behind_rc;
         FreeXid(xid);