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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 /include
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 'include')
-rw-r--r--include/linux/dax.h26
1 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 0dd316a74a29..becaea5f4488 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -19,6 +19,12 @@ struct dax_operations {
*/
long (*direct_access)(struct dax_device *, pgoff_t, long,
void **, pfn_t *);
+ /*
+ * Validate whether this device is usable as an fsdax backing
+ * device.
+ */
+ bool (*dax_supported)(struct dax_device *, struct block_device *, int,
+ sector_t, sector_t);
/* copy_from_iter: required operation for fs-dax direct-i/o */
size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
struct iov_iter *);
@@ -75,6 +81,17 @@ static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
return __bdev_dax_supported(bdev, blocksize);
}
+bool __generic_fsdax_supported(struct dax_device *dax_dev,
+ struct block_device *bdev, int blocksize, sector_t start,
+ sector_t sectors);
+static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
+ struct block_device *bdev, int blocksize, sector_t start,
+ sector_t sectors)
+{
+ return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
+ sectors);
+}
+
static inline struct dax_device *fs_dax_get_by_host(const char *host)
{
return dax_get_by_host(host);
@@ -99,6 +116,13 @@ static inline bool bdev_dax_supported(struct block_device *bdev,
return false;
}
+static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
+ struct block_device *bdev, int blocksize, sector_t start,
+ sector_t sectors)
+{
+ return false;
+}
+
static inline struct dax_device *fs_dax_get_by_host(const char *host)
{
return NULL;
@@ -142,6 +166,8 @@ bool dax_alive(struct dax_device *dax_dev);
void *dax_get_private(struct dax_device *dax_dev);
long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
void **kaddr, pfn_t *pfn);
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+ int blocksize, sector_t start, sector_t len);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i);
size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,