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libnvdimm fixes for 5.9-rc6

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- Fix an original bug in device-mapper table reference counting when
   interrogating dax capability in the component device. This bug was
   hidden by the following bug.
 
 - Fix device-mapper to use the proper helper (dax_supported() instead of
   the leaf helper generic_fsdax_supported()) to determine dax operation
   of a stacked block device configuration. The original implementation
   is only valid for one level of dax-capable block device stacking. This
   bug was discovered while fixing the below regression.
 
 - Fix an infinite recursion regression introduced by broken attempts to
   quiet the generic_fsdax_supported() path and make it bail out before
   logging "dax capability not found" errors.
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Merge tag 'libnvdimm-fixes-5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm fixes from Dan Williams:
 "A handful of fixes to address a string of mistakes in the mechanism
  for device-mapper to determine if its component devices are dax
  capable.

   - Fix an original bug in device-mapper table reference counting when
     interrogating dax capability in the component device. This bug was
     hidden by the following bug.

   - Fix device-mapper to use the proper helper (dax_supported() instead
     of the leaf helper generic_fsdax_supported()) to determine dax
     operation of a stacked block device configuration. The original
     implementation is only valid for one level of dax-capable block
     device stacking. This bug was discovered while fixing the below
     regression.

   - Fix an infinite recursion regression introduced by broken attempts
     to quiet the generic_fsdax_supported() path and make it bail out
     before logging "dax capability not found" errors"

* tag 'libnvdimm-fixes-5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: Fix stack overflow when mounting fsdax pmem device
  dm: Call proper helper to determine dax support
  dm/dax: Fix table reference counts
This commit is contained in:
Linus Torvalds 2020-09-20 15:01:57 -07:00
commit 4a123dbaf3
4 changed files with 40 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/dax/super.c
View File

@ -85,6 +85,12 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
if (!dax_dev) {
pr_debug("%s: error: dax unsupported by block device\n",
bdevname(bdev, buf));
return false;
}
err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);
if (err) {
pr_info("%s: error: unaligned partition for dax\n",
@ -100,12 +106,6 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
if (!dax_dev || !bdev_dax_supported(bdev, blocksize)) {
pr_debug("%s: error: dax unsupported by block device\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);
@ -325,11 +325,15 @@ 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_dev)
return false;
if (!dax_alive(dax_dev))
return false;
return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
}
EXPORT_SYMBOL_GPL(dax_supported);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i)

10
drivers/md/dm-table.c
View File

@ -860,10 +860,14 @@ EXPORT_SYMBOL_GPL(dm_table_set_type);
int device_supports_dax(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
int blocksize = *(int *) data;
int blocksize = *(int *) data, id;
bool rc;
return generic_fsdax_supported(dev->dax_dev, dev->bdev, blocksize,
start, len);
id = dax_read_lock();
rc = dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);
dax_read_unlock(id);
return rc;
}
/* Check devices support synchronous DAX */

5
drivers/md/dm.c
View File

@ -1136,15 +1136,16 @@ static bool dm_dax_supported(struct dax_device *dax_dev, struct block_device *bd
{
struct mapped_device *md = dax_get_private(dax_dev);
struct dm_table *map;
bool ret = false;
int srcu_idx;
bool ret;
map = dm_get_live_table(md, &srcu_idx);
if (!map)
return false;
goto out;
ret = dm_table_supports_dax(map, device_supports_dax, &blocksize);
out:
dm_put_live_table(md, srcu_idx);
return ret;

22
include/linux/dax.h
View File

@ -130,6 +130,8 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
sectors);
}
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len);
static inline void fs_put_dax(struct dax_device *dax_dev)
{
@ -157,6 +159,13 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
static inline bool dax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t len)
{
return false;
}
static inline void fs_put_dax(struct dax_device *dax_dev)
{
}
@ -189,14 +198,23 @@ static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
}
#endif
#if IS_ENABLED(CONFIG_DAX)
int dax_read_lock(void);
void dax_read_unlock(int id);
#else
static inline int dax_read_lock(void)
{
return 0;
}
static inline void dax_read_unlock(int id)
{
}
#endif /* CONFIG_DAX */
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,