Merge tag 'dm-3.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device-mapper updates from Mike Snitzer:
 "Add the ability to collect I/O statistics on user-defined regions of a
  device-mapper device.  This dm-stats code required the reintroduction
  of a div64_u64_rem() helper, but as a separate method that doesn't
  slow down div64_u64() -- especially on 32-bit systems.

  Allow the error target to replace request-based DM devices (e.g.
  multipath) in addition to bio-based DM devices.

  Various other small code fixes and improvements to thin-provisioning,
  DM cache and the DM ioctl interface"

* tag 'dm-3.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm stripe: silence a couple sparse warnings
  dm: add statistics support
  dm thin: always return -ENOSPC if no_free_space is set
  dm ioctl: cleanup error handling in table_load
  dm ioctl: increase granularity of type_lock when loading table
  dm ioctl: prevent rename to empty name or uuid
  dm thin: set pool read-only if breaking_sharing fails block allocation
  dm thin: prefix pool error messages with pool device name
  dm: allow error target to replace bio-based and request-based targets
  math64: New separate div64_u64_rem helper
  dm space map: optimise sm_ll_dec and sm_ll_inc
  dm btree: prefetch child nodes when walking tree for a dm_btree_del
  dm btree: use pop_frame in dm_btree_del to cleanup code
  dm cache: eliminate holes in cache structure
  dm cache: fix stacking of geometry limits
  dm thin: fix stacking of geometry limits
  dm thin: add data block size limits to Documentation
  dm cache: add data block size limits to code and Documentation
  dm cache: document metadata device is exclussive to a cache
  dm: stop using WQ_NON_REENTRANT

1 files changed, 35 insertions, 24 deletions

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 0df3ec0..2956976 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -67,9 +67,11 @@ static void free_bitset(unsigned long *bits)
 #define MIGRATION_COUNT_WINDOW 10
 
 /*
- * The block size of the device holding cache data must be >= 32KB
+ * The block size of the device holding cache data must be
+ * between 32KB and 1GB.
  */
 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)
+#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
 
 /*
  * FIXME: the cache is read/write for the time being.
@@ -101,6 +103,8 @@ struct cache {
 	struct dm_target *ti;
 	struct dm_target_callbacks callbacks;
 
+	struct dm_cache_metadata *cmd;
+
 	/*
 	 * Metadata is written to this device.
 	 */
@@ -117,11 +121,6 @@ struct cache {
 	struct dm_dev *cache_dev;
 
 	/*
-	 * Cache features such as write-through.
-	 */
-	struct cache_features features;
-
-	/*
 	 * Size of the origin device in _complete_ blocks and native sectors.
 	 */
 	dm_oblock_t origin_blocks;
@@ -138,8 +137,6 @@ struct cache {
 	uint32_t sectors_per_block;
 	int sectors_per_block_shift;
 
-	struct dm_cache_metadata *cmd;
-
 	spinlock_t lock;
 	struct bio_list deferred_bios;
 	struct bio_list deferred_flush_bios;
@@ -148,8 +145,8 @@ struct cache {
 	struct list_head completed_migrations;
 	struct list_head need_commit_migrations;
 	sector_t migration_threshold;
-	atomic_t nr_migrations;
 	wait_queue_head_t migration_wait;
+	atomic_t nr_migrations;
 
 	/*
 	 * cache_size entries, dirty if set
@@ -160,9 +157,16 @@ struct cache {
 	/*
 	 * origin_blocks entries, discarded if set.
 	 */
-	uint32_t discard_block_size; /* a power of 2 times sectors per block */
 	dm_dblock_t discard_nr_blocks;
 	unsigned long *discard_bitset;
+	uint32_t discard_block_size; /* a power of 2 times sectors per block */
+
+	/*
+	 * Rather than reconstructing the table line for the status we just
+	 * save it and regurgitate.
+	 */
+	unsigned nr_ctr_args;
+	const char **ctr_args;
 
 	struct dm_kcopyd_client *copier;
 	struct workqueue_struct *wq;
@@ -187,14 +191,12 @@ struct cache {
 	bool loaded_mappings:1;
 	bool loaded_discards:1;
 
-	struct cache_stats stats;
-
 	/*
-	 * Rather than reconstructing the table line for the status we just
-	 * save it and regurgitate.
+	 * Cache features such as write-through.
 	 */
-	unsigned nr_ctr_args;
-	const char **ctr_args;
+	struct cache_features features;
+
+	struct cache_stats stats;
 };
 
 struct per_bio_data {
@@ -1687,24 +1689,25 @@ static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
 static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
 			    char **error)
 {
-	unsigned long tmp;
+	unsigned long block_size;
 
 	if (!at_least_one_arg(as, error))
 		return -EINVAL;
 
-	if (kstrtoul(dm_shift_arg(as), 10, &tmp) || !tmp ||
-	    tmp < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
-	    tmp & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
+	if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size ||
+	    block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
+	    block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
+	    block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
 		*error = "Invalid data block size";
 		return -EINVAL;
 	}
 
-	if (tmp > ca->cache_sectors) {
+	if (block_size > ca->cache_sectors) {
 		*error = "Data block size is larger than the cache device";
 		return -EINVAL;
 	}
 
-	ca->block_size = tmp;
+	ca->block_size = block_size;
 
 	return 0;
 }
@@ -2609,9 +2612,17 @@ static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
 {
 	struct cache *cache = ti->private;
+	uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
 
-	blk_limits_io_min(limits, 0);
-	blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
+	/*
+	 * If the system-determined stacked limits are compatible with the
+	 * cache's blocksize (io_opt is a factor) do not override them.
+	 */
+	if (io_opt_sectors < cache->sectors_per_block ||
+	    do_div(io_opt_sectors, cache->sectors_per_block)) {
+		blk_limits_io_min(limits, 0);
+		blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
+	}
 	set_discard_limits(cache, limits);
 }