Commit 6cdc577a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-5.1/dm-changes' of... 

Merge tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Update bio-based DM core to always call blk_queue_split() and update
   DM targets to properly advertise discard limits that
   blk_queue_split() looks at when dtermining to split discard. Whereby
   allowing DM core's own 'split_discard_bios' to be removed.

 - Improve DM cache target to provide support for discard passdown to
   the origin device.

 - Introduce support to directly boot to a DM mapped device from init by
   using dm-mod.create= module param. This eliminates the need for an
   elaborate initramfs that is otherwise needed to create DM devices.

   This feature's implementation has been worked on for quite some time
   (got up to v12) and is of particular interest to Android and other
   more embedded platforms (e.g. ARM).

 - Rate limit errors from the DM integrity target that were identified
   as the cause for recent NMI hangs due to console limitations.

 - Add sanity checks for user input to thin-pool and external snapshot
   creation.

 - Remove some unused leftover kmem caches from when old .request_fn
   request-based support was removed.

 - Various small cleanups and fixes to targets (e.g. typos, needless
   unlikely() annotations, use struct_size(), remove needless
   .direct_access method from dm-snapshot)

* tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm integrity: limit the rate of error messages
  dm snapshot: don't define direct_access if we don't support it
  dm cache: add support for discard passdown to the origin device
  dm writecache: fix typo in name for writeback_wq
  dm: add support to directly boot to a mapped device
  dm thin: add sanity checks to thin-pool and external snapshot creation
  dm block manager: remove redundant unlikely annotation
  dm verity fec: remove redundant unlikely annotation
  dm integrity: remove redundant unlikely annotation
  dm: always call blk_queue_split() in dm_process_bio()
  dm: fix to_sector() for 32bit
  dm switch: use struct_size() in kzalloc()
  dm: remove unused _rq_tio_cache and _rq_cache
  dm: eliminate 'split_discard_bios' flag from DM target interface
  dm: update dm_process_bio() to split bio if in ->make_request_fn()
parents 92fff53b 22555744

Documentation/device-mapper/cache.txt

+3 −0
Original line number Diff line number Diff line
@@ -206,6 +206,9 @@ Optional feature arguments are: 
                  in a separate btree, which improves speed of shutting

		  down the cache.



   no_discard_passdown	: disable passing down discards from the cache

			  to the origin's data device.



A policy called 'default' is always registered.  This is an alias for

the policy we currently think is giving best all round performance.

Documentation/device-mapper/dm-init.txt

0 → 100644
+114 −0
Original line number Diff line number Diff line 
Early creation of mapped devices

====================================



It is possible to configure a device-mapper device to act as the root device for

your system in two ways.



The first is to build an initial ramdisk which boots to a minimal userspace

which configures the device, then pivot_root(8) in to it.



The second is to create one or more device-mappers using the module parameter

"dm-mod.create=" through the kernel boot command line argument.



The format is specified as a string of data separated by commas and optionally

semi-colons, where:

 - a comma is used to separate fields like name, uuid, flags and table

   (specifies one device)

 - a semi-colon is used to separate devices.



So the format will look like this:



 dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+]



Where,

	<name>		::= The device name.

	<uuid>		::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | ""

	<minor>		::= The device minor number | ""

	<flags>		::= "ro" | "rw"

	<table>		::= <start_sector> <num_sectors> <target_type> <target_args>

	<target_type>	::= "verity" | "linear" | ... (see list below)



The dm line should be equivalent to the one used by the dmsetup tool with the

--concise argument.



Target types

============



Not all target types are available as there are serious risks in allowing

activation of certain DM targets without first using userspace tools to check

the validity of associated metadata.



	"cache":		constrained, userspace should verify cache device

	"crypt":		allowed

	"delay":		allowed

	"era":			constrained, userspace should verify metadata device

	"flakey":		constrained, meant for test

	"linear":		allowed

	"log-writes":		constrained, userspace should verify metadata device

	"mirror":		constrained, userspace should verify main/mirror device

	"raid":			constrained, userspace should verify metadata device

	"snapshot":		constrained, userspace should verify src/dst device

	"snapshot-origin":	allowed

	"snapshot-merge":	constrained, userspace should verify src/dst device

	"striped":		allowed

	"switch":		constrained, userspace should verify dev path

	"thin":			constrained, requires dm target message from userspace

	"thin-pool":		constrained, requires dm target message from userspace

	"verity":		allowed

	"writecache":		constrained, userspace should verify cache device

	"zero":			constrained, not meant for rootfs



If the target is not listed above, it is constrained by default (not tested).



Examples

========

An example of booting to a linear array made up of user-mode linux block

devices:



  dm-mod.create="lroot,,,rw, 0 4096 linear 98:16 0, 4096 4096 linear 98:32 0" root=/dev/dm-0



This will boot to a rw dm-linear target of 8192 sectors split across two block

devices identified by their major:minor numbers.  After boot, udev will rename

this target to /dev/mapper/lroot (depending on the rules). No uuid was assigned.



An example of multiple device-mappers, with the dm-mod.create="..." contents is shown here

split on multiple lines for readability:



  vroot,,,ro,

    0 1740800 verity 254:0 254:0 1740800 sha1

      76e9be054b15884a9fa85973e9cb274c93afadb6

      5b3549d54d6c7a3837b9b81ed72e49463a64c03680c47835bef94d768e5646fe;

  vram,,,rw,

    0 32768 linear 1:0 0,

    32768 32768 linear 1:1 0



Other examples (per target):



"crypt":

  dm-crypt,,8,ro,

    0 1048576 crypt aes-xts-plain64

    babebabebabebabebabebabebabebabebabebabebabebabebabebabebabebabe 0

    /dev/sda 0 1 allow_discards



"delay":

  dm-delay,,4,ro,0 409600 delay /dev/sda1 0 500



"linear":

  dm-linear,,,rw,

    0 32768 linear /dev/sda1 0,

    32768 1024000 linear /dev/sda2 0,

    1056768 204800 linear /dev/sda3 0,

    1261568 512000 linear /dev/sda4 0



"snapshot-origin":

  dm-snap-orig,,4,ro,0 409600 snapshot-origin 8:2



"striped":

  dm-striped,,4,ro,0 1638400 striped 4 4096

  /dev/sda1 0 /dev/sda2 0 /dev/sda3 0 /dev/sda4 0



"verity":

  dm-verity,,4,ro,

    0 1638400 verity 1 8:1 8:2 4096 4096 204800 1 sha256

    fb1a5a0f00deb908d8b53cb270858975e76cf64105d412ce764225d53b8f3cfd

    51934789604d1b92399c52e7cb149d1b3a1b74bbbcb103b2a0aaacbed5c08584

drivers/md/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -436,6 +436,18 @@ config DM_DELAY 


	If unsure, say N.



config DM_INIT

	bool "DM \"dm-mod.create=\" parameter support"

	depends on BLK_DEV_DM=y

	---help---

	Enable "dm-mod.create=" parameter to create mapped devices at init time.

	This option is useful to allow mounting rootfs without requiring an

	initramfs.

	See Documentation/device-mapper/dm-init.txt for dm-mod.create="..."

	format.



	If unsure, say N.



config DM_UEVENT

	bool "DM uevents"

	depends on BLK_DEV_DM

drivers/md/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -69,6 +69,10 @@ obj-$(CONFIG_DM_INTEGRITY) += dm-integrity.o 
obj-$(CONFIG_DM_ZONED)		+= dm-zoned.o

obj-$(CONFIG_DM_WRITECACHE)	+= dm-writecache.o



ifeq ($(CONFIG_DM_INIT),y)

dm-mod-objs			+= dm-init.o

endif



ifeq ($(CONFIG_DM_UEVENT),y)

dm-mod-objs			+= dm-uevent.o

endif

drivers/md/dm-cache-target.c

+100 −27
Original line number Diff line number Diff line
@@ -353,6 +353,7 @@ struct cache_features { 
	enum cache_metadata_mode mode;

	enum cache_io_mode io_mode;

	unsigned metadata_version;

	bool discard_passdown:1;

};



struct cache_stats {
@@ -1899,6 +1900,10 @@ static bool process_discard_bio(struct cache *cache, struct bio *bio) 
		b = to_dblock(from_dblock(b) + 1);

	}



	if (cache->features.discard_passdown) {

		remap_to_origin(cache, bio);

		generic_make_request(bio);

	} else

		bio_endio(bio);



	return false;
@@ -2233,13 +2238,14 @@ static void init_features(struct cache_features *cf) 
	cf->mode = CM_WRITE;

	cf->io_mode = CM_IO_WRITEBACK;

	cf->metadata_version = 1;

	cf->discard_passdown = true;

}



static int parse_features(struct cache_args *ca, struct dm_arg_set *as,

			  char **error)

{

	static const struct dm_arg _args[] = {

		{0, 2, "Invalid number of cache feature arguments"},

		{0, 3, "Invalid number of cache feature arguments"},

	};



	int r, mode_ctr = 0;
@@ -2274,6 +2280,9 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as, 
		else if (!strcasecmp(arg, "metadata2"))

			cf->metadata_version = 2;



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

			cf->discard_passdown = false;



		else {

			*error = "Unrecognised cache feature requested";

			return -EINVAL;
@@ -2496,7 +2505,6 @@ static int cache_create(struct cache_args *ca, struct cache **result) 


	ti->num_discard_bios = 1;

	ti->discards_supported = true;

	ti->split_discard_bios = false;



	ti->per_io_data_size = sizeof(struct per_bio_data);
@@ -3120,6 +3128,39 @@ static void cache_resume(struct dm_target *ti) 
	do_waker(&cache->waker.work);

}



static void emit_flags(struct cache *cache, char *result,

		       unsigned maxlen, ssize_t *sz_ptr)

{

	ssize_t sz = *sz_ptr;

	struct cache_features *cf = &cache->features;

	unsigned count = (cf->metadata_version == 2) + !cf->discard_passdown + 1;



	DMEMIT("%u ", count);



	if (cf->metadata_version == 2)

		DMEMIT("metadata2 ");



	if (writethrough_mode(cache))

		DMEMIT("writethrough ");



	else if (passthrough_mode(cache))

		DMEMIT("passthrough ");



	else if (writeback_mode(cache))

		DMEMIT("writeback ");



	else {

		DMEMIT("unknown ");

		DMERR("%s: internal error: unknown io mode: %d",

		      cache_device_name(cache), (int) cf->io_mode);

	}



	if (!cf->discard_passdown)

		DMEMIT("no_discard_passdown ");



	*sz_ptr = sz;

}



/*

 * Status format:

 *
@@ -3186,25 +3227,7 @@ static void cache_status(struct dm_target *ti, status_type_t type, 
		       (unsigned) atomic_read(&cache->stats.promotion),

		       (unsigned long) atomic_read(&cache->nr_dirty));



		if (cache->features.metadata_version == 2)

			DMEMIT("2 metadata2 ");

		else

			DMEMIT("1 ");



		if (writethrough_mode(cache))

			DMEMIT("writethrough ");



		else if (passthrough_mode(cache))

			DMEMIT("passthrough ");



		else if (writeback_mode(cache))

			DMEMIT("writeback ");



		else {

			DMERR("%s: internal error: unknown io mode: %d",

			      cache_device_name(cache), (int) cache->features.io_mode);

			goto err;

		}

		emit_flags(cache, result, maxlen, &sz);



		DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
@@ -3433,14 +3456,62 @@ static int cache_iterate_devices(struct dm_target *ti, 
	return r;

}



static void set_discard_limits(struct cache *cache, struct queue_limits *limits)

static bool origin_dev_supports_discard(struct block_device *origin_bdev)

{

	struct request_queue *q = bdev_get_queue(origin_bdev);



	return q && blk_queue_discard(q);

}



/*

	 * FIXME: these limits may be incompatible with the cache device

 * If discard_passdown was enabled verify that the origin device

 * supports discards.  Disable discard_passdown if not.

 */

static void disable_passdown_if_not_supported(struct cache *cache)

{

	struct block_device *origin_bdev = cache->origin_dev->bdev;

	struct queue_limits *origin_limits = &bdev_get_queue(origin_bdev)->limits;

	const char *reason = NULL;

	char buf[BDEVNAME_SIZE];



	if (!cache->features.discard_passdown)

		return;



	if (!origin_dev_supports_discard(origin_bdev))

		reason = "discard unsupported";



	else if (origin_limits->max_discard_sectors < cache->sectors_per_block)

		reason = "max discard sectors smaller than a block";



	if (reason) {

		DMWARN("Origin device (%s) %s: Disabling discard passdown.",

		       bdevname(origin_bdev, buf), reason);

		cache->features.discard_passdown = false;

	}

}



static void set_discard_limits(struct cache *cache, struct queue_limits *limits)

{

	struct block_device *origin_bdev = cache->origin_dev->bdev;

	struct queue_limits *origin_limits = &bdev_get_queue(origin_bdev)->limits;



	if (!cache->features.discard_passdown) {

		/* No passdown is done so setting own virtual limits */

		limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024,

						    cache->origin_sectors);

		limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;

		return;

	}



	/*

	 * cache_iterate_devices() is stacking both origin and fast device limits

	 * but discards aren't passed to fast device, so inherit origin's limits.

	 */

	limits->max_discard_sectors = origin_limits->max_discard_sectors;

	limits->max_hw_discard_sectors = origin_limits->max_hw_discard_sectors;

	limits->discard_granularity = origin_limits->discard_granularity;

	limits->discard_alignment = origin_limits->discard_alignment;

	limits->discard_misaligned = origin_limits->discard_misaligned;

}



static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
@@ -3457,6 +3528,8 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) 
		blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT);

		blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);

	}



	disable_passdown_if_not_supported(cache);

	set_discard_limits(cache, limits);

}
@@ -3464,7 +3537,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) 


static struct target_type cache_target = {

	.name = "cache",

	.version = {2, 0, 0},

	.version = {2, 1, 0},

	.module = THIS_MODULE,

	.ctr = cache_ctr,

	.dtr = cache_dtr,

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