quota: Acquire dqio_sem for reading in dquot_get_next_id()
dquot_get_next_id() needs dqio_sem only for reading to protect against
racing with modification of quota file structure.
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 21358f3..8d5ccad 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2079,9 +2079,9 @@ int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
return -ESRCH;
if (!dqopt->ops[qid->type]->get_next_id)
return -ENOSYS;
- down_write(&dqopt->dqio_sem);
+ down_read(&dqopt->dqio_sem);
err = dqopt->ops[qid->type]->get_next_id(sb, qid);
- up_write(&dqopt->dqio_sem);
+ up_read(&dqopt->dqio_sem);
return err;
}
EXPORT_SYMBOL(dquot_get_next_id);