loop: fix no-unmap write-zeroes request behavior (efcfec57) · Commits · 戴 / test

drivers/block/loop.c

+18 −8

Original line number	Diff line number	Diff line
		@@ -417,18 +417,20 @@ out_free_page:
		return ret;
		}

		static int lo_discard(struct loop_device lo, struct request rq, loff_t pos)
		static int lo_fallocate(struct loop_device lo, struct request rq, loff_t pos,
		int mode)
		{
		/*
		* We use punch hole to reclaim the free space used by the
		* image a.k.a. discard. However we do not support discard if
		* encryption is enabled, because it may give an attacker
		* useful information.
		* We use fallocate to manipulate the space mappings used by the image
		* a.k.a. discard/zerorange. However we do not support this if
		* encryption is enabled, because it may give an attacker useful
		* information.
		*/
		struct file *file = lo->lo_backing_file;
		int mode = FALLOC_FL_PUNCH_HOLE \| FALLOC_FL_KEEP_SIZE;
		int ret;

		mode \|= FALLOC_FL_KEEP_SIZE;

		if ((!file->f_op->fallocate) \|\| lo->lo_encrypt_key_size) {
		ret = -EOPNOTSUPP;
		goto out;
		@@ -596,9 +598,17 @@ static int do_req_filebacked(struct loop_device lo, struct request rq)
		switch (req_op(rq)) {
		case REQ_OP_FLUSH:
		return lo_req_flush(lo, rq);
		case REQ_OP_DISCARD:
		case REQ_OP_WRITE_ZEROES:
		return lo_discard(lo, rq, pos);
		/*
		* If the caller doesn't want deallocation, call zeroout to
		* write zeroes the range. Otherwise, punch them out.
		*/
		return lo_fallocate(lo, rq, pos,
		(rq->cmd_flags & REQ_NOUNMAP) ?
		FALLOC_FL_ZERO_RANGE :
		FALLOC_FL_PUNCH_HOLE);
		case REQ_OP_DISCARD:
		return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
		case REQ_OP_WRITE:
		if (lo->transfer)
		return lo_write_transfer(lo, rq, pos);