diff options
| -rw-r--r-- | drivers/md/dm-thin.c | 87 |
1 files changed, 57 insertions, 30 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index e99f4134dbd7..c29410af1e22 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -580,7 +580,8 @@ struct pool_c { struct dm_target_callbacks callbacks; dm_block_t low_water_blocks; - struct pool_features pf; + struct pool_features requested_pf; /* Features requested during table load */ + struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */ }; /* @@ -1848,21 +1849,36 @@ static bool data_dev_supports_discard(struct pool_c *pt) /* * If discard_passdown was enabled verify that the data device - * supports discards. Disable discard_passdown if not; otherwise - * -EOPNOTSUPP will be returned. + * supports discards. Disable discard_passdown if not. */ -static void disable_passdown_if_not_supported(struct pool_c *pt, - struct pool_features *pf) +static void disable_passdown_if_not_supported(struct pool_c *pt) { + struct pool *pool = pt->pool; + struct block_device *data_bdev = pt->data_dev->bdev; + struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits; + sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT; + const char *reason = NULL; char buf[BDEVNAME_SIZE]; - if (!pf->discard_passdown || data_dev_supports_discard(pt)) + if (!pt->adjusted_pf.discard_passdown) return; - DMWARN("Discard unsupported by data device (%s): Disabling discard passdown.", - bdevname(pt->data_dev->bdev, buf)); + if (!data_dev_supports_discard(pt)) + reason = "discard unsupported"; + + else if (data_limits->max_discard_sectors < pool->sectors_per_block) + reason = "max discard sectors smaller than a block"; - pf->discard_passdown = false; + else if (data_limits->discard_granularity > block_size) + reason = "discard granularity larger than a block"; + + else if (block_size & (data_limits->discard_granularity - 1)) + reason = "discard granularity not a factor of block size"; + + if (reason) { + DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason); + pt->adjusted_pf.discard_passdown = false; + } } static int bind_control_target(struct pool *pool, struct dm_target *ti) @@ -1873,16 +1889,15 @@ static int bind_control_target(struct pool *pool, struct dm_target *ti) * We want to make sure that degraded pools are never upgraded. */ enum pool_mode old_mode = pool->pf.mode; - enum pool_mode new_mode = pt->pf.mode; + enum pool_mode new_mode = pt->adjusted_pf.mode; if (old_mode > new_mode) new_mode = old_mode; pool->ti = ti; pool->low_water_blocks = pt->low_water_blocks; - pool->pf = pt->pf; + pool->pf = pt->adjusted_pf; - disable_passdown_if_not_supported(pt, &pool->pf); set_pool_mode(pool, new_mode); return 0; @@ -2271,7 +2286,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) pt->metadata_dev = metadata_dev; pt->data_dev = data_dev; pt->low_water_blocks = low_water_blocks; - pt->pf = pf; + pt->adjusted_pf = pt->requested_pf = pf; ti->num_flush_requests = 1; /* @@ -2718,7 +2733,7 @@ static int pool_status(struct dm_target *ti, status_type_t type, format_dev_t(buf2, pt->data_dev->bdev->bd_dev), (unsigned long)pool->sectors_per_block, (unsigned long long)pt->low_water_blocks); - emit_flags(&pt->pf, result, sz, maxlen); + emit_flags(&pt->requested_pf, result, sz, maxlen); break; } @@ -2747,19 +2762,21 @@ static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm, return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); } -static void set_discard_limits(struct pool *pool, struct queue_limits *limits) +static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits) { - /* - * FIXME: these limits may be incompatible with the pool's data device - */ + struct pool *pool = pt->pool; + struct queue_limits *data_limits; + limits->max_discard_sectors = pool->sectors_per_block; /* - * This is just a hint, and not enforced. We have to cope with - * bios that cover a block partially. A discard that spans a block - * boundary is not sent to this target. + * discard_granularity is just a hint, and not enforced. */ - limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; + if (pt->adjusted_pf.discard_passdown) { + data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits; + limits->discard_granularity = data_limits->discard_granularity; + } else + limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; } static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) @@ -2769,15 +2786,25 @@ static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) blk_limits_io_min(limits, 0); blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); - if (pool->pf.discard_enabled) - set_discard_limits(pool, limits); + + /* + * pt->adjusted_pf is a staging area for the actual features to use. + * They get transferred to the live pool in bind_control_target() + * called from pool_preresume(). + */ + if (!pt->adjusted_pf.discard_enabled) + return; + + disable_passdown_if_not_supported(pt); + + set_discard_limits(pt, limits); } static struct target_type pool_target = { .name = "thin-pool", .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | DM_TARGET_IMMUTABLE, - .version = {1, 3, 0}, + .version = {1, 4, 0}, .module = THIS_MODULE, .ctr = pool_ctr, .dtr = pool_dtr, @@ -3056,19 +3083,19 @@ static int thin_iterate_devices(struct dm_target *ti, return 0; } +/* + * A thin device always inherits its queue limits from its pool. + */ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct thin_c *tc = ti->private; - struct pool *pool = tc->pool; - blk_limits_io_min(limits, 0); - blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); - set_discard_limits(pool, limits); + *limits = bdev_get_queue(tc->pool_dev->bdev)->limits; } static struct target_type thin_target = { .name = "thin", - .version = {1, 3, 0}, + .version = {1, 4, 0}, .module = THIS_MODULE, .ctr = thin_ctr, .dtr = thin_dtr, |