quota: add missing lock into __dquot_transfer()

Lock dq_dqb_lock around dquot_decr_inodes()

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 7b9ca4c61bc2 ("quota: Reduce contention on dq_data_lock")
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 2 insertions, 0 deletions

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;
                 }
         }