From dd88d313bef0277e27597aa394607ed26c658724 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Mon, 8 May 2017 16:40:43 -0700 Subject: [PATCH] dm table: add zoned block devices validation 1) Introduce DM_TARGET_ZONED_HM feature flag: The target drivers currently available will not operate correctly if a table target maps onto a host-managed zoned block device. To avoid problems, introduce the new feature flag DM_TARGET_ZONED_HM to allow a target to explicitly state that it supports host-managed zoned block devices. This feature is checked for all targets in a table if any of the table's block devices are host-managed. Note that as host-aware zoned block devices are backward compatible with regular block devices, they can be used by any of the current target types. This new feature is thus restricted to host-managed zoned block devices. 2) Check device area zone alignment: If a target maps to a zoned block device, check that the device area is aligned on zone boundaries to avoid problems with REQ_OP_ZONE_RESET operations (resetting a partially mapped sequential zone would not be possible). This also facilitates the processing of zone report with REQ_OP_ZONE_REPORT bios. 3) Check block devices zone model compatibility When setting the DM device's queue limits, several possibilities exists for zoned block devices: 1) The DM target driver may want to expose a different zone model (e.g. host-managed device emulation or regular block device on top of host-managed zoned block devices) 2) Expose the underlying zone model of the devices as-is To allow both cases, the underlying block device zone model must be set in the target limits in dm_set_device_limits() and the compatibility of all devices checked similarly to the logical block size alignment. For this last check, introduce validate_hardware_zoned_model() to check that all targets of a table have the same zone model and that the zone size of the target devices are equal. Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Reviewed-by: Bart Van Assche [Mike Snitzer refactored Damien's original work to simplify the code] Signed-off-by: Mike Snitzer --- drivers/md/dm-table.c | 162 ++++++++++++++++++++++++++++++++++ include/linux/device-mapper.h | 6 ++ 2 files changed, 168 insertions(+) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 5f5eae41f804..a39bcd9b982a 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -319,6 +319,39 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev, return 1; } + /* + * If the target is mapped to zoned block device(s), check + * that the zones are not partially mapped. + */ + if (bdev_zoned_model(bdev) != BLK_ZONED_NONE) { + unsigned int zone_sectors = bdev_zone_sectors(bdev); + + if (start & (zone_sectors - 1)) { + DMWARN("%s: start=%llu not aligned to h/w zone size %u of %s", + dm_device_name(ti->table->md), + (unsigned long long)start, + zone_sectors, bdevname(bdev, b)); + return 1; + } + + /* + * Note: The last zone of a zoned block device may be smaller + * than other zones. So for a target mapping the end of a + * zoned block device with such a zone, len would not be zone + * aligned. We do not allow such last smaller zone to be part + * of the mapping here to ensure that mappings with multiple + * devices do not end up with a smaller zone in the middle of + * the sector range. + */ + if (len & (zone_sectors - 1)) { + DMWARN("%s: len=%llu not aligned to h/w zone size %u of %s", + dm_device_name(ti->table->md), + (unsigned long long)len, + zone_sectors, bdevname(bdev, b)); + return 1; + } + } + if (logical_block_size_sectors <= 1) return 0; @@ -456,6 +489,8 @@ static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, q->limits.alignment_offset, (unsigned long long) start << SECTOR_SHIFT); + limits->zoned = blk_queue_zoned_model(q); + return 0; } @@ -1346,6 +1381,88 @@ bool dm_table_has_no_data_devices(struct dm_table *table) return true; } +static int device_is_zoned_model(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct request_queue *q = bdev_get_queue(dev->bdev); + enum blk_zoned_model *zoned_model = data; + + return q && blk_queue_zoned_model(q) == *zoned_model; +} + +static bool dm_table_supports_zoned_model(struct dm_table *t, + enum blk_zoned_model zoned_model) +{ + struct dm_target *ti; + unsigned i; + + for (i = 0; i < dm_table_get_num_targets(t); i++) { + ti = dm_table_get_target(t, i); + + if (zoned_model == BLK_ZONED_HM && + !dm_target_supports_zoned_hm(ti->type)) + return false; + + if (!ti->type->iterate_devices || + !ti->type->iterate_devices(ti, device_is_zoned_model, &zoned_model)) + return false; + } + + return true; +} + +static int device_matches_zone_sectors(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct request_queue *q = bdev_get_queue(dev->bdev); + unsigned int *zone_sectors = data; + + return q && blk_queue_zone_sectors(q) == *zone_sectors; +} + +static bool dm_table_matches_zone_sectors(struct dm_table *t, + unsigned int zone_sectors) +{ + struct dm_target *ti; + unsigned i; + + for (i = 0; i < dm_table_get_num_targets(t); i++) { + ti = dm_table_get_target(t, i); + + if (!ti->type->iterate_devices || + !ti->type->iterate_devices(ti, device_matches_zone_sectors, &zone_sectors)) + return false; + } + + return true; +} + +static int validate_hardware_zoned_model(struct dm_table *table, + enum blk_zoned_model zoned_model, + unsigned int zone_sectors) +{ + if (zoned_model == BLK_ZONED_NONE) + return 0; + + if (!dm_table_supports_zoned_model(table, zoned_model)) { + DMERR("%s: zoned model is not consistent across all devices", + dm_device_name(table->md)); + return -EINVAL; + } + + /* Check zone size validity and compatibility */ + if (!zone_sectors || !is_power_of_2(zone_sectors)) + return -EINVAL; + + if (!dm_table_matches_zone_sectors(table, zone_sectors)) { + DMERR("%s: zone sectors is not consistent across all devices", + dm_device_name(table->md)); + return -EINVAL; + } + + return 0; +} + /* * Establish the new table's queue_limits and validate them. */ @@ -1355,6 +1472,8 @@ int dm_calculate_queue_limits(struct dm_table *table, struct dm_target *ti; struct queue_limits ti_limits; unsigned i; + enum blk_zoned_model zoned_model = BLK_ZONED_NONE; + unsigned int zone_sectors = 0; blk_set_stacking_limits(limits); @@ -1372,6 +1491,15 @@ int dm_calculate_queue_limits(struct dm_table *table, ti->type->iterate_devices(ti, dm_set_device_limits, &ti_limits); + if (zoned_model == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) { + /* + * After stacking all limits, validate all devices + * in table support this zoned model and zone sectors. + */ + zoned_model = ti_limits.zoned; + zone_sectors = ti_limits.chunk_sectors; + } + /* Set I/O hints portion of queue limits */ if (ti->type->io_hints) ti->type->io_hints(ti, &ti_limits); @@ -1396,8 +1524,42 @@ int dm_calculate_queue_limits(struct dm_table *table, dm_device_name(table->md), (unsigned long long) ti->begin, (unsigned long long) ti->len); + + /* + * FIXME: this should likely be moved to blk_stack_limits(), would + * also eliminate limits->zoned stacking hack in dm_set_device_limits() + */ + if (limits->zoned == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) { + /* + * By default, the stacked limits zoned model is set to + * BLK_ZONED_NONE in blk_set_stacking_limits(). Update + * this model using the first target model reported + * that is not BLK_ZONED_NONE. This will be either the + * first target device zoned model or the model reported + * by the target .io_hints. + */ + limits->zoned = ti_limits.zoned; + } } + /* + * Verify that the zoned model and zone sectors, as determined before + * any .io_hints override, are the same across all devices in the table. + * - this is especially relevant if .io_hints is emulating a disk-managed + * zoned model (aka BLK_ZONED_NONE) on host-managed zoned block devices. + * BUT... + */ + if (limits->zoned != BLK_ZONED_NONE) { + /* + * ...IF the above limits stacking determined a zoned model + * validate that all of the table's devices conform to it. + */ + zoned_model = limits->zoned; + zone_sectors = limits->chunk_sectors; + } + if (validate_hardware_zoned_model(table, zoned_model, zone_sectors)) + return -EINVAL; + return validate_hardware_logical_block_alignment(table, limits); } diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 19bc7fdfd6da..186ef74009cb 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -237,6 +237,12 @@ typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio) #define DM_TARGET_PASSES_INTEGRITY 0x00000020 #define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY) +/* + * Indicates that a target supports host-managed zoned block devices. + */ +#define DM_TARGET_ZONED_HM 0x00000040 +#define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM) + struct dm_target { struct dm_table *table; struct target_type *type; -- GitLab