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dax: Arrange for dax_supported check to span multiple devices

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Pankaj reports that starting with commit ad428cdb52 "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: ad428cdb52 ("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>
This commit is contained in:
Dan Williams 2019-05-16 13:26:29 -07:00
parent c01dafad77
commit 7bf7eac8d6
7 changed files with 117 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
drivers/dax/super.c
View File

@ -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)
{

15
drivers/md/dm-table.c
View File

@ -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)
{
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);

20
drivers/md/dm.c
View File

@ -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,
};

1
drivers/md/dm.h
View File

@ -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);

1
drivers/nvdimm/pmem.c
View File

@ -295,6 +295,7 @@ static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,
static const struct dax_operations pmem_dax_ops = {
.direct_access = pmem_dax_direct_access,
.dax_supported = generic_fsdax_supported,
.copy_from_iter = pmem_copy_from_iter,
.copy_to_iter = pmem_copy_to_iter,
};

1
drivers/s390/block/dcssblk.c
View File

@ -59,6 +59,7 @@ static size_t dcssblk_dax_copy_to_iter(struct dax_device *dax_dev,
static const struct dax_operations dcssblk_dax_ops = {
.direct_access = dcssblk_dax_direct_access,
.dax_supported = generic_fsdax_supported,
.copy_from_iter = dcssblk_dax_copy_from_iter,
.copy_to_iter = dcssblk_dax_copy_to_iter,
};

26
include/linux/dax.h
View File

@ -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,