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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 /drivers/dax
parentc01dafad77fea8d64c4fdca0a6031c980842ad65 (diff)
downloadlinux-7bf7eac8d648057519adb6fce1e31458c902212c.tar.bz2
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/dax')
-rw-r--r--drivers/dax/super.c88
1 files changed, 57 insertions, 31 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index bbd57ca0634a..3a7b0a0bf469 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -73,22 +73,12 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
#endif
-/**
- * __bdev_dax_supported() - Check if the device supports dax for filesystem
- * @bdev: block device to check
- * @blocksize: The block size of the device
- *
- * This is a library function for filesystems to check if the block device
- * can be mounted with dax option.
- *
- * Return: true if supported, false if unsupported
- */
-bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
+bool __generic_fsdax_supported(struct dax_device *dax_dev,
+ struct block_device *bdev, int blocksize, sector_t start,
+ sector_t sectors)
{
- struct dax_device *dax_dev;
bool dax_enabled = false;
pgoff_t pgoff, pgoff_end;
- struct request_queue *q;
char buf[BDEVNAME_SIZE];
void *kaddr, *end_kaddr;
pfn_t pfn, end_pfn;
@@ -102,21 +92,14 @@ bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
return false;
}
- q = bdev_get_queue(bdev);
- if (!q || !blk_queue_dax(q)) {
- pr_debug("%s: error: request queue doesn't support dax\n",
- bdevname(bdev, buf));
- return false;
- }
-
- err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff);
+ err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);
if (err) {
pr_debug("%s: error: unaligned partition for dax\n",
bdevname(bdev, buf));
return false;
}
- last_page = PFN_DOWN(i_size_read(bdev->bd_inode) - 1) * 8;
+ last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512;
err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end);
if (err) {
pr_debug("%s: error: unaligned partition for dax\n",
@@ -124,20 +107,11 @@ bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
return false;
}
- dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
- if (!dax_dev) {
- pr_debug("%s: error: device does not support dax\n",
- bdevname(bdev, buf));
- return false;
- }
-
id = dax_read_lock();
len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
dax_read_unlock(id);
- put_dax(dax_dev);
-
if (len < 1 || len2 < 1) {
pr_debug("%s: error: dax access failed (%ld)\n",
bdevname(bdev, buf), len < 1 ? len : len2);
@@ -178,6 +152,49 @@ bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
}
return true;
}
+EXPORT_SYMBOL_GPL(__generic_fsdax_supported);
+
+/**
+ * __bdev_dax_supported() - Check if the device supports dax for filesystem
+ * @bdev: block device to check
+ * @blocksize: The block size of the device
+ *
+ * This is a library function for filesystems to check if the block device
+ * can be mounted with dax option.
+ *
+ * Return: true if supported, false if unsupported
+ */
+bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
+{
+ struct dax_device *dax_dev;
+ struct request_queue *q;
+ char buf[BDEVNAME_SIZE];
+ bool ret;
+ int id;
+
+ q = bdev_get_queue(bdev);
+ if (!q || !blk_queue_dax(q)) {
+ pr_debug("%s: error: request queue doesn't support dax\n",
+ bdevname(bdev, buf));
+ return false;
+ }
+
+ dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+ if (!dax_dev) {
+ pr_debug("%s: error: device does not support dax\n",
+ bdevname(bdev, buf));
+ return false;
+ }
+
+ id = dax_read_lock();
+ ret = dax_supported(dax_dev, bdev, blocksize, 0,
+ i_size_read(bdev->bd_inode) / 512);
+ dax_read_unlock(id);
+
+ put_dax(dax_dev);
+
+ return ret;
+}
EXPORT_SYMBOL_GPL(__bdev_dax_supported);
#endif
@@ -303,6 +320,15 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
}
EXPORT_SYMBOL_GPL(dax_direct_access);
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+ int blocksize, sector_t start, sector_t len)
+{
+ if (!dax_alive(dax_dev))
+ return false;
+
+ return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
+}
+
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i)
{