quota: add missing use of dq_data_lock in __dquot_initialize

The bulk of __dquot_initialize runs under the dqptr_sem which
protects the inode->i_dquot pointers. It doesn't protect the
dereferenced contents, though. Those are protected by the
dq_data_lock, which is missing around the dquot_resv_space call.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 05ae3c97f7a5..3e64169ef527 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -1439,8 +1439,11 @@ static void __dquot_initialize(struct inode *inode, int type)
                          * did a write before quota was turned on
                          */
                         rsv = inode_get_rsv_space(inode);
-                        if (unlikely(rsv))
+                        if (unlikely(rsv)) {
+                                spin_lock(&dq_data_lock);
                                 dquot_resv_space(inode->i_dquot[cnt], rsv);
+                                spin_unlock(&dq_data_lock);
+                        }
                 }
         }
 out_err: