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-rw-r--r--fs/quota/quota_v2.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/fs/quota/quota_v2.c b/fs/quota/quota_v2.c
index 482733abe4ac..7a05b80f3b8c 100644
--- a/fs/quota/quota_v2.c
+++ b/fs/quota/quota_v2.c
@@ -300,12 +300,23 @@ static int v2_write_dquot(struct dquot *dquot)
{
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
int ret;
-
- down_write(&dqopt->dqio_sem);
+ bool alloc = false;
+
+ /*
+ * If space for dquot is already allocated, we don't need any
+ * protection as we'll only overwrite the place of dquot. We are
+ * still protected by concurrent writes of the same dquot by
+ * dquot->dq_lock.
+ */
+ if (!dquot->dq_off) {
+ alloc = true;
+ down_write(&dqopt->dqio_sem);
+ }
ret = qtree_write_dquot(
sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
dquot);
- up_write(&dqopt->dqio_sem);
+ if (alloc)
+ up_write(&dqopt->dqio_sem);
return ret;
}