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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-09 17:40:27 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-09 17:40:27 -0800 |
commit | 6cdc577a18a616c331f57e268c97466171cfc45f (patch) | |
tree | 95fba928918a06b32ed59efb2de7e8ba1513e78b /drivers/md/dm-cache-target.c | |
parent | 92fff53b7191cae566be9ca6752069426c7f8241 (diff) | |
parent | 225557446856448039a9e495da37b72c20071ef2 (diff) | |
download | linux-6cdc577a18a616c331f57e268c97466171cfc45f.tar.bz2 |
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()
Diffstat (limited to 'drivers/md/dm-cache-target.c')
-rw-r--r-- | drivers/md/dm-cache-target.c | 127 |
1 files changed, 100 insertions, 27 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index b29a8327eed1..d249cf8ac277 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -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 { @@ -1899,7 +1900,11 @@ static bool process_discard_bio(struct cache *cache, struct bio *bio) b = to_dblock(from_dblock(b) + 1); } - bio_endio(bio); + 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 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); +} + +/* + * 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; + } + /* - * FIXME: these limits may be incompatible with the cache device + * 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 = min_t(sector_t, cache->discard_block_size * 1024, - cache->origin_sectors); - limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; + 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, |