quota: Do not acquire dqio_sem for dquot overwrites in v2 format (d2faa415) · Commits · 戴 / test

When dquot has space already allocated in a quota file, we just overwrite that place when writing dquot. So we don't need any protection against other modifications of quota file as these keep dquot in place. Reviewed-by:

Andreas Dilger <adilger@dilger.ca> Signed-off-by:

Jan Kara <jack@suse.cz>

fs/quota/quota_v2.c

+14 −3

Original line number	Diff line number	Diff line
		@@ -300,11 +300,22 @@ static int v2_write_dquot(struct dquot *dquot)
		{
		struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
		int ret;
		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);
		if (alloc)
		up_write(&dqopt->dqio_sem);
		return ret;
		}

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