Commit af9313c3 authored by John Pittman's avatar John Pittman Committed by Mike Snitzer
Browse files

dm cache: only allow a single io_mode cache feature to be requested 



More than one io_mode feature can be requested when creating a dm cache
device (as is: last one wins).  The io_mode selections are incompatible
with one another, we should force them to be selected exclusively.  Add
a counter to check for more than one io_mode selection.

Fixes: 629d0a8a ("dm cache metadata: add "metadata2" feature")
Signed-off-by: default avatarJohn Pittman <jpittman@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 6c7413c0

drivers/md/dm-cache-target.c

+15 −4
Original line number Diff line number Diff line
@@ -2250,7 +2250,7 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as, 
		{0, 2, "Invalid number of cache feature arguments"},

	};



	int r;

	int r, mode_ctr = 0;

	unsigned argc;

	const char *arg;

	struct cache_features *cf = &ca->features;
@@ -2264,14 +2264,20 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as, 
	while (argc--) {

		arg = dm_shift_arg(as);



		if (!strcasecmp(arg, "writeback"))

		if (!strcasecmp(arg, "writeback")) {

			cf->io_mode = CM_IO_WRITEBACK;

			mode_ctr++;

		}



		else if (!strcasecmp(arg, "writethrough"))

		else if (!strcasecmp(arg, "writethrough")) {

			cf->io_mode = CM_IO_WRITETHROUGH;

			mode_ctr++;

		}



		else if (!strcasecmp(arg, "passthrough"))

		else if (!strcasecmp(arg, "passthrough")) {

			cf->io_mode = CM_IO_PASSTHROUGH;

			mode_ctr++;

		}



		else if (!strcasecmp(arg, "metadata2"))

			cf->metadata_version = 2;
@@ -2282,6 +2288,11 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as, 
		}

	}



	if (mode_ctr > 1) {

		*error = "Duplicate cache io_mode features requested";

		return -EINVAL;

	}



	return 0;

}

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