path: root/drivers/md
diff options
authorDan Williams <dan.j.williams@intel.com>2019-05-16 13:26:29 -0700
committerDan Williams <dan.j.williams@intel.com>2019-05-20 15:02:08 -0700
commit7bf7eac8d648057519adb6fce1e31458c902212c (patch)
tree1d4489b03dd6ef2526c41de62d525fdc5a1842ea /drivers/md
parentc01dafad77fea8d64c4fdca0a6031c980842ad65 (diff)
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: <stable@vger.kernel.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Reviewed-by: Jan Kara <jack@suse.cz> Reported-by: Pankaj Gupta <pagupta@redhat.com> Reviewed-by: Pankaj Gupta <pagupta@redhat.com> Tested-by: Pankaj Gupta <pagupta@redhat.com> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/md')
3 files changed, 32 insertions, 6 deletions
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)
+/* 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)
/* 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)) {
} 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);
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);