[PATCH] quota: add missing lock into __dquot_transfer()

[Konstantin Khlebnikov]

Lock dq_dqb_lock around dquot_decr_inodes()

Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
Fixes: 7b9ca4c61bc2 ("quota: Reduce contention on dq_data_lock")
---
 fs/quota/dquot.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 8381db9db6d9..50b0556a124f 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -1980,7 +1980,9 @@ int __dquot_transfer(struct inode *inode, struct dquot 
**transfer_to)
                ret = dquot_add_space(transfer_to[cnt], cur_space, rsv_space, 0,
                                      &warn_to[cnt]);
                if (ret) {
+                       spin_lock(&transfer_to[cnt]->dq_dqb_lock);
                        dquot_decr_inodes(transfer_to[cnt], inode_usage);
+                       spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
                        goto over_quota;
                }
        }