From 7bf7eac8d648057519adb6fce1e31458c902212c Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 16 May 2019 13:26:29 -0700 Subject: dax: Arrange for dax_supported check to span multiple devices Pankaj reports that starting with commit ad428cdb525a "dax: Check the end of the block-device capacity with dax_direct_access()" device-mapper no longer allows dax operation. This results from the stricter checks in __bdev_dax_supported() that validate that the start and end of a block-device map to the same 'pagemap' instance. Teach the dax-core and device-mapper to validate the 'pagemap' on a per-target basis. This is accomplished by refactoring the bdev_dax_supported() internals into generic_fsdax_supported() which takes a sector range to validate. Consequently generic_fsdax_supported() is suitable to be used in a device-mapper ->iterate_devices() callback. A new ->dax_supported() operation is added to allow composite devices to split and route upper-level bdev_dax_supported() requests. Fixes: ad428cdb525a ("dax: Check the end of the block-device...") Cc: Cc: Ira Weiny Cc: Dave Jiang Cc: Keith Busch Cc: Matthew Wilcox Cc: Vishal Verma Cc: Heiko Carstens Cc: Martin Schwidefsky Reviewed-by: Jan Kara Reported-by: Pankaj Gupta Reviewed-by: Pankaj Gupta Tested-by: Pankaj Gupta Tested-by: Vaibhav Jain Reviewed-by: Mike Snitzer Signed-off-by: Dan Williams --- drivers/md/dm-table.c | 17 +++++++++++------ drivers/md/dm.c | 20 ++++++++++++++++++++ drivers/md/dm.h | 1 + 3 files changed, 32 insertions(+), 6 deletions(-) (limited to 'drivers/md') diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index cde3b49b2a91..350cf0451456 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -880,13 +880,17 @@ void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type) } EXPORT_SYMBOL_GPL(dm_table_set_type); +/* validate the dax capability of the target device span */ static int device_supports_dax(struct dm_target *ti, struct dm_dev *dev, - sector_t start, sector_t len, void *data) + sector_t start, sector_t len, void *data) { - return bdev_dax_supported(dev->bdev, PAGE_SIZE); + int blocksize = *(int *) data; + + return generic_fsdax_supported(dev->dax_dev, dev->bdev, blocksize, + start, len); } -static bool dm_table_supports_dax(struct dm_table *t) +bool dm_table_supports_dax(struct dm_table *t, int blocksize) { struct dm_target *ti; unsigned i; @@ -899,7 +903,8 @@ static bool dm_table_supports_dax(struct dm_table *t) return false; if (!ti->type->iterate_devices || - !ti->type->iterate_devices(ti, device_supports_dax, NULL)) + !ti->type->iterate_devices(ti, device_supports_dax, + &blocksize)) return false; } @@ -979,7 +984,7 @@ static int dm_table_determine_type(struct dm_table *t) verify_bio_based: /* We must use this table as bio-based */ t->type = DM_TYPE_BIO_BASED; - if (dm_table_supports_dax(t) || + if (dm_table_supports_dax(t, PAGE_SIZE) || (list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED)) { t->type = DM_TYPE_DAX_BIO_BASED; } else { @@ -1905,7 +1910,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, } blk_queue_write_cache(q, wc, fua); - if (dm_table_supports_dax(t)) + if (dm_table_supports_dax(t, PAGE_SIZE)) blk_queue_flag_set(QUEUE_FLAG_DAX, q); else blk_queue_flag_clear(QUEUE_FLAG_DAX, q); diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 1fb1333fefec..b7c0ad01084d 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1107,6 +1107,25 @@ static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, return ret; } +static bool dm_dax_supported(struct dax_device *dax_dev, struct block_device *bdev, + int blocksize, sector_t start, sector_t len) +{ + struct mapped_device *md = dax_get_private(dax_dev); + struct dm_table *map; + int srcu_idx; + bool ret; + + map = dm_get_live_table(md, &srcu_idx); + if (!map) + return false; + + ret = dm_table_supports_dax(map, blocksize); + + dm_put_live_table(md, srcu_idx); + + return ret; +} + static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i) { @@ -3192,6 +3211,7 @@ static const struct block_device_operations dm_blk_dops = { static const struct dax_operations dm_dax_ops = { .direct_access = dm_dax_direct_access, + .dax_supported = dm_dax_supported, .copy_from_iter = dm_dax_copy_from_iter, .copy_to_iter = dm_dax_copy_to_iter, }; diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 2d539b82ec08..17e3db54404c 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -72,6 +72,7 @@ bool dm_table_bio_based(struct dm_table *t); bool dm_table_request_based(struct dm_table *t); void dm_table_free_md_mempools(struct dm_table *t); struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t); +bool dm_table_supports_dax(struct dm_table *t, int blocksize); void dm_lock_md_type(struct mapped_device *md); void dm_unlock_md_type(struct mapped_device *md); -- cgit v1.2.3