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Commit 9677b54a authored by Neeraj Upadhyay's avatar Neeraj Upadhyay Committed by Gerrit - the friendly Code Review server
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dm verity: Add an optional arg to wait for target devices 



Add an optional arg (device_wait) to allow indefinite
wait for target dm devices. This could be required for
devices which come up asynchronously. As existing
implementation had some of the optional args dependent
on processing of required args, introduce a new function
to allow optional args pre processing, for args which
affect the processing of required args.

Change-Id: I61af9a6136cefaf5e20cc08c0c891d838ad75b7f
Signed-off-by: default avatarNeeraj Upadhyay <neeraju@codeaurora.org>
parent 83d88163

Documentation/device-mapper/verity.txt

+4 −0
Original line number Diff line number Diff line
@@ -71,6 +71,10 @@ Construction Parameters 
    Example of optional parameters section:

        1 ignore_corruption



device_wait

    Wait (indefinitely) for target devices to show up. Useful for devices

    that are detected asynchronously.



ignore_corruption

    Log corrupted blocks, but allow read operations to proceed normally.

drivers/md/dm-verity-target.c

+58 −1
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include "dm-verity.h"

#include "dm-verity-fec.h"



#include <linux/delay.h>

#include <linux/module.h>

#include <linux/reboot.h>

#include <linux/vmalloc.h>
@@ -30,17 +31,20 @@ 


#define DM_VERITY_MAX_CORRUPTED_ERRS	100



#define DM_VERITY_OPT_DEVICE_WAIT	"device_wait"

#define DM_VERITY_OPT_LOGGING		"ignore_corruption"

#define DM_VERITY_OPT_RESTART		"restart_on_corruption"

#define DM_VERITY_OPT_IGN_ZEROES	"ignore_zero_blocks"

#define DM_VERITY_OPT_AT_MOST_ONCE	"check_at_most_once"



#define DM_VERITY_OPTS_MAX		(2 + DM_VERITY_OPTS_FEC)

#define DM_VERITY_OPTS_MAX		(3 + DM_VERITY_OPTS_FEC)



static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;



module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);



static int dm_device_wait;



struct dm_verity_prefetch_work {

	struct work_struct work;

	struct dm_verity *v;
@@ -810,6 +814,38 @@ static int verity_alloc_zero_digest(struct dm_verity *v) 
	return r;

}



static int verity_parse_pre_opt_args(struct dm_arg_set *as,

					struct dm_verity *v)

{

	int r;

	unsigned int argc;

	const char *arg_name;

	struct dm_target *ti = v->ti;

	static struct dm_arg _args[] = {

		{0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"},

	};



	r = dm_read_arg_group(_args, as, &argc, &ti->error);

	if (r)

		return -EINVAL;



	if (!argc)

		return 0;



	do {

		arg_name = dm_shift_arg(as);

		argc--;



		if (!strcasecmp(arg_name, DM_VERITY_OPT_DEVICE_WAIT)) {

			dm_device_wait = 1;

			continue;

		}



	} while (argc);



	return 0;

}



static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)

{

	int r;
@@ -859,6 +895,8 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v) 
			if (r)

				return r;

			continue;

		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_DEVICE_WAIT)) {

			continue;

		}



		ti->error = "Unrecognized verity feature request";
@@ -917,6 +955,15 @@ int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) 
		goto bad;

	}



	/* Optional parameters which are parsed pre required args. */

	if ((argc - 10)) {

		as.argc = argc - 10;

		as.argv = argv + 10;

		r = verity_parse_pre_opt_args(&as, v);

		if (r < 0)

			goto bad;

	}



	if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||

	    num > 1) {

		ti->error = "Invalid version";
@@ -925,14 +972,24 @@ int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) 
	}

	v->version = num;



retry_dev1:

	r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev);

	if (r) {

		if (r == -ENODEV && dm_device_wait) {

			msleep(100);

			goto retry_dev1;

		}

		ti->error = "Data device lookup failed";

		goto bad;

	}



retry_dev2:

	r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev);

	if (r) {

		if (r == -ENODEV && dm_device_wait) {

			msleep(100);

			goto retry_dev2;

		}

		ti->error = "Data device lookup failed";

		goto bad;

	}