linux.git/fs/dax.c, branch v5.15

Merge tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

2021-08-31T18:13:35+00:00

Pull iomap updates from Darrick Wong:
 "The most notable externally visible change for this cycle is the
  addition of support for reads to inline tail fragments of files, which
  was requested by the erofs developers; and a correction for a kernel
  memory corruption bug if the sysadmin tries to activate a swapfile
  with more pages than the swapfile header suggests.

  We also now report writeback completion errors to the file mapping
  correctly, instead of munging all errors into EIO.

  Internally, the bulk of the changes are Christoph's patchset to reduce
  the indirect function call count by a third to a half by converting
  iomap iteration from a loop pattern to a generator/consumer pattern.
  As an added bonus, fsdax no longer open-codes iomap apply loops.

  Summary:

   - Simplify the bio_end_page usage in the buffered IO code.

   - Support reading inline data at nonzero offsets for erofs.

   - Fix some typos and bad grammar.

   - Convert kmap_atomic usage in the inline data read path.

   - Add some extra inline data input checking.

   - Fix a memory corruption bug stemming from iomap_swapfile_activate
     trying to activate more pages than mm was expecting.

   - Pass errnos through the page writeback code so that writeback
     errors are reported correctly instead of being munged to EIO.

   - Replace iomap_apply with a open-coded iterator loops to reduce the
     number of indirect calls by a third to a half.

   - Refactor the fsdax code to use iomap iterators instead of the
     open-coded iomap_apply code that it had before.

   - Format file range iomap tracepoint data in hexadecimal and
     standardize the names used in the pretty-print string"

* tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (41 commits)
  iomap: standardize tracepoint formatting and storage
  mm/swap: consider max pages in iomap_swapfile_add_extent
  iomap: move loop control code to iter.c
  iomap: constify iomap_iter_srcmap
  fsdax: switch the fault handlers to use iomap_iter
  fsdax: factor out a dax_fault_actor() helper
  fsdax: factor out helpers to simplify the dax fault code
  iomap: rework unshare flag
  iomap: pass an iomap_iter to various buffered I/O helpers
  iomap: remove iomap_apply
  fsdax: switch dax_iomap_rw to use iomap_iter
  iomap: switch iomap_swapfile_activate to use iomap_iter
  iomap: switch iomap_seek_data to use iomap_iter
  iomap: switch iomap_seek_hole to use iomap_iter
  iomap: switch iomap_bmap to use iomap_iter
  iomap: switch iomap_fiemap to use iomap_iter
  iomap: switch __iomap_dio_rw to use iomap_iter
  iomap: switch iomap_page_mkwrite to use iomap_iter
  iomap: switch iomap_zero_range to use iomap_iter
  iomap: switch iomap_file_unshare to use iomap_iter
  ...

fsdax: switch the fault handlers to use iomap_iter

2021-08-17T04:26:33+00:00

Avoid the open coded calls to ->iomap_begin and ->iomap_end and call
iomap_iter instead.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

fsdax: factor out a dax_fault_actor() helper

2021-08-17T04:26:33+00:00

The core logic in the two dax page fault functions is similar. So, move
the logic into a common helper function. Also, to facilitate the
addition of new features, such as CoW, switch-case is no longer used to
handle different iomap types.

Signed-off-by: Shiyang Ruan 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Ritesh Harjani 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Darrick J. Wong

fsdax: factor out helpers to simplify the dax fault code

2021-08-17T04:26:33+00:00

The dax page fault code is too long and a bit difficult to read. And it
is hard to understand when we trying to add new features. Some of the
PTE/PMD codes have similar logic. So, factor out helper functions to
simplify the code.

Signed-off-by: Shiyang Ruan 
Reviewed-by: Ritesh Harjani 
Reviewed-by: Darrick J. Wong 
[hch: minor cleanups]
Signed-off-by: Christoph Hellwig 
Signed-off-by: Darrick J. Wong

fsdax: switch dax_iomap_rw to use iomap_iter

2021-08-17T04:26:33+00:00

Switch the dax_iomap_rw implementation to use iomap_iter.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

fsdax: mark the iomap argument to dax_iomap_sector as const

2021-08-17T04:26:33+00:00

Signed-off-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

Merge branch 'for-5.14/dax' into libnvdimm-fixes

2021-08-11T19:04:43+00:00

Pick up some small dax cleanups that make some of Ira's follow on work
easier.

fs/dax: Clarify nr_pages to dax_direct_access()

2021-07-08T05:10:03+00:00

dax_direct_access() takes a number of pages.  PHYS_PFN(PAGE_SIZE) is a
very round about way to specify '1'.

Change the nr_pages parameter to the explicit value of '1'.

Reviewed-by: Dan Williams 
Signed-off-by: Ira Weiny 
Link: https://lore.kernel.org/r/20210525172428.3634316-3-ira.weiny@intel.com
Signed-off-by: Dan Williams

dax: fix ENOMEM handling in grab_mapping_entry()

2021-06-29T17:53:47+00:00

grab_mapping_entry() has a bug in handling of ENOMEM condition.  Suppose
we have a PMD entry at index i which we are downgrading to a PTE entry.
grab_mapping_entry() will set pmd_downgrade to true, lock the entry, clear
the entry in xarray, and decrement mapping->nrpages.  The it will call:

	entry = dax_make_entry(pfn_to_pfn_t(0), flags);
	dax_lock_entry(xas, entry);

which inserts new PTE entry into xarray.  However this may fail allocating
the new node.  We handle this by:

	if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM))
		goto retry;

however pmd_downgrade stays set to true even though 'entry' returned from
get_unlocked_entry() will be NULL now.  And we will go again through the
downgrade branch.  This is mostly harmless except that mapping->nrpages is
decremented again and we temporarily have an invalid entry stored in
xarray.  Fix the problem by setting pmd_downgrade to false each time we
lookup the entry we work with so that it matches the entry we found.

Link: https://lkml.kernel.org/r/20210622160015.18004-1-jack@suse.cz
Fixes: b15cd800682f ("dax: Convert page fault handlers to XArray")
Signed-off-by: Jan Kara 
Reviewed-by: Dan Williams 
Cc: Matthew Wilcox 
Cc: "Aneesh Kumar K.V" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'dax-fixes-5.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2021-05-15T15:28:08+00:00

Pull dax fixes from Dan Williams:
 "A fix for a hang condition due to missed wakeups in the filesystem-dax
  core when exercised by virtiofs.

  This bug has been there from the beginning, but the condition has
  not triggered on other filesystems since they hold a lock over
  invalidation events"

* tag 'dax-fixes-5.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: Wake up all waiters after invalidating dax entry
  dax: Add a wakeup mode parameter to put_unlocked_entry()
  dax: Add an enum for specifying dax wakup mode