linux-stable.git/include/linux/pagemap.h, branch v5.10.78

mm, futex: fix shared futex pgoff on shmem huge page

2021-06-30T12:47:29+00:00

commit fe19bd3dae3d15d2fbfdb3de8839a6ea0fe94264 upstream.

If more than one futex is placed on a shmem huge page, it can happen
that waking the second wakes the first instead, and leaves the second
waiting: the key's shared.pgoff is wrong.

When 3.11 commit 13d60f4b6ab5 ("futex: Take hugepages into account when
generating futex_key"), the only shared huge pages came from hugetlbfs,
and the code added to deal with its exceptional page->index was put into
hugetlb source.  Then that was missed when 4.8 added shmem huge pages.

page_to_pgoff() is what others use for this nowadays: except that, as
currently written, it gives the right answer on hugetlbfs head, but
nonsense on hugetlbfs tails.  Fix that by calling hugetlbfs-specific
hugetlb_basepage_index() on PageHuge tails as well as on head.

Yes, it's unconventional to declare hugetlb_basepage_index() there in
pagemap.h, rather than in hugetlb.h; but I do not expect anything but
page_to_pgoff() ever to need it.

[akpm@linux-foundation.org: give hugetlb_basepage_index() prototype the correct scope]

Link: https://lkml.kernel.org/r/b17d946b-d09-326e-b42a-52884c36df32@google.com
Fixes: 800d8c63b2e9 ("shmem: add huge pages support")
Reported-by: Neel Natu 
Signed-off-by: Hugh Dickins 
Reviewed-by: Matthew Wilcox (Oracle) 
Acked-by: Thomas Gleixner 
Cc: "Kirill A. Shutemov" 
Cc: Zhang Yi 
Cc: Mel Gorman 
Cc: Mike Kravetz 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Darren Hart 
Cc: Davidlohr Bueso 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

fs/cachefiles: Remove wait_bit_key layout dependency

2021-03-30T12:32:07+00:00

commit 39f985c8f667c80a3d1eb19d31138032fa36b09e upstream.

Cachefiles was relying on wait_page_key and wait_bit_key being the
same layout, which is fragile.  Now that wait_page_key is exposed in
the pagemap.h header, we can remove that fragility

A comment on the need to maintain structure layout equivalence was added by
Linus[1] and that is no longer applicable.

Fixes: 62906027091f ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Christoph Hellwig 
Signed-off-by: David Howells 
Tested-by: kafs-testing@auristor.com
cc: linux-cachefs@redhat.com
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20210320054104.1300774-2-willy@infradead.org/
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3510ca20ece0150af6b10c77a74ff1b5c198e3e2 [1]
Signed-off-by: Greg Kroah-Hartman

mm: fix readahead_page_batch for retry entries

2020-11-22T18:48:22+00:00

Both btrfs and fuse have reported faults caused by seeing a retry entry
instead of the page they were looking for.  This was caused by a missing
check in the iterator.

As can be seen in the below panic log, the accessing 0x402 causes a
panic.  In the xarray.h, 0x402 means RETRY_ENTRY.

  BUG: kernel NULL pointer dereference, address: 0000000000000402
  CPU: 14 PID: 306003 Comm: as Not tainted 5.9.0-1-amd64 #1 Debian 5.9.1-1
  Hardware name: Lenovo ThinkSystem SR665/7D2VCTO1WW, BIOS D8E106Q-1.01 05/30/2020
  RIP: 0010:fuse_readahead+0x152/0x470 [fuse]
  Code: 41 8b 57 18 4c 8d 54 10 ff 4c 89 d6 48 8d 7c 24 10 e8 d2 e3 28 f9 48 85 c0 0f 84 fe 00 00 00 44 89 f2 49 89 04 d4 44 8d 72 01 <48> 8b 10 41 8b 4f 1c 48 c1 ea 10 83 e2 01 80 fa 01 19 d2 81 e2 01
  RSP: 0018:ffffad99ceaebc50 EFLAGS: 00010246
  RAX: 0000000000000402 RBX: 0000000000000001 RCX: 0000000000000002
  RDX: 0000000000000000 RSI: ffff94c5af90bd98 RDI: ffffad99ceaebc60
  RBP: ffff94ddc1749a00 R08: 0000000000000402 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000100 R12: ffff94de6c429ce0
  R13: ffff94de6c4d3700 R14: 0000000000000001 R15: ffffad99ceaebd68
  FS:  00007f228c5c7040(0000) GS:ffff94de8ed80000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000402 CR3: 0000001dbd9b4000 CR4: 0000000000350ee0
  Call Trace:
    read_pages+0x83/0x270
    page_cache_readahead_unbounded+0x197/0x230
    generic_file_buffered_read+0x57a/0xa20
    new_sync_read+0x112/0x1a0
    vfs_read+0xf8/0x180
    ksys_read+0x5f/0xe0
    do_syscall_64+0x33/0x80
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 042124cc64c3 ("mm: add new readahead_control API")
Reported-by: David Sterba 
Reported-by: Wonhyuk Yang 
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: 
Link: https://lkml.kernel.org/r/20201103142852.8543-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20201103124349.16722-1-vvghjk1234@gmail.com
Signed-off-by: Linus Torvalds

mm: pagemap.h: fix two kernel-doc markups

2020-10-28T17:41:14+00:00

Changeset a8cf7f272b5a ("mm: add find_lock_head") renamed the
index parameter, but forgot to update the kernel-doc markups
accordingly.

Fixes: a8cf7f272b5a ("mm: add find_lock_head")
Signed-off-by: Mauro Carvalho Chehab 
Reviewed-by: Matthew Wilcox (Oracle) 
Link: https://lore.kernel.org/r/dce89b296a4f5f9f8f798d5e76b6736c14a916ac.1603791716.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet

mm/readahead: add page_cache_sync_ra and page_cache_async_ra

2020-10-16T18:11:16+00:00

Reimplement page_cache_sync_readahead() and page_cache_async_readahead()
as wrappers around versions of the function which take a readahead_control
in preparation for making do_sync_mmap_readahead() pass down an RAC
struct.

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: David Howells 
Cc: Eric Biggers 
Link: https://lkml.kernel.org/r/20200903140844.14194-8-willy@infradead.org
Signed-off-by: Linus Torvalds

mm/readahead: make page_cache_ra_unbounded take a readahead_control

2020-10-16T18:11:16+00:00

Define it in the callers instead of in page_cache_ra_unbounded().

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: David Howells 
Cc: Eric Biggers 
Link: https://lkml.kernel.org/r/20200903140844.14194-4-willy@infradead.org
Signed-off-by: Linus Torvalds

mm/readahead: add DEFINE_READAHEAD

2020-10-16T18:11:15+00:00

Patch series "Readahead patches for 5.9/5.10".

These are infrastructure for both the THP patchset and for the fscache
rewrite,

For both pieces of infrastructure being build on top of this patchset, we
want the ractl to be available higher in the call-stack.

For David's work, he wants to add the 'critical page' to the ractl so that
he knows which page NEEDS to be brought in from storage, and which ones
are nice-to-have.  We might want something similar in block storage too.
It used to be simple -- the first page was the critical one, but then mmap
added fault-around and so for that usecase, the middle page is the
critical one.  Anyway, I don't have any code to show that yet, we just
know that the lowest point in the callchain where we have that information
is do_sync_mmap_readahead() and so the ractl needs to start its life
there.

For THP, we havew the code that needs it.  It's actually the apex patch to
the series; the one which finally starts to allocate THPs and present them
to consenting filesystems:
http://git.infradead.org/users/willy/pagecache.git/commitdiff/798bcf30ab2eff278caad03a9edca74d2f8ae760

This patch (of 8):

Allow for a more concise definition of a struct readahead_control.

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: Eric Biggers 
Cc: David Howells 
Link: https://lkml.kernel.org/r/20200903140844.14194-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20200903140844.14194-3-willy@infradead.org
Signed-off-by: Linus Torvalds

fs: do not update nr_thps for mappings which support THPs

2020-10-16T18:11:15+00:00

The nr_thps counter is to support THPs in the page cache when the
filesystem doesn't understand THPs.  Eventually it will be removed, but we
should still support filesystems which do not understand THPs yet.  Move
the nr_thp manipulation functions to filemap.h since they're page-cache
specific.

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: Alexander Viro 
Cc: "Matthew Wilcox (Oracle)" 
Cc: Hugh Dickins 
Cc: Song Liu 
Cc: Rik van Riel 
Cc: "Kirill A . Shutemov" 
Cc: Johannes Weiner 
Cc: Dave Chinner 
Cc: Christoph Hellwig 
Link: https://lkml.kernel.org/r/20200916032717.22917-2-willy@infradead.org
Signed-off-by: Linus Torvalds

fs: add a filesystem flag for THPs

2020-10-16T18:11:15+00:00

The page cache needs to know whether the filesystem supports THPs so that
it doesn't send THPs to filesystems which can't handle them.  Dave Chinner
points out that getting from the page mapping to the filesystem type is
too many steps (mapping->host->i_sb->s_type->fs_flags) so cache that
information in the address space flags.

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: Alexander Viro 
Cc: "Matthew Wilcox (Oracle)" 
Cc: Hugh Dickins 
Cc: Song Liu 
Cc: Rik van Riel 
Cc: "Kirill A . Shutemov" 
Cc: Johannes Weiner 
Cc: Dave Chinner 
Cc: Christoph Hellwig 
Link: https://lkml.kernel.org/r/20200916032717.22917-1-willy@infradead.org
Signed-off-by: Linus Torvalds

Merge tag 'iomap-5.10-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

2020-10-14T19:23:00+00:00

Pull iomap updates from Darrick Wong:
 "There's not a lot of new stuff going on here -- a little bit of code
  refactoring to make iomap workable with btrfs' fsync locking model,
  cleanups in preparation for adding THP support for filesystems, and
  fixing a data corruption issue for blocksize < pagesize filesystems.

  Summary:

   - Don't WARN_ON weird states that unprivileged users can create.

   - Don't invalidate page cache when direct writes want to fall back to
     buffered.

   - Fix some problems when readahead ios fail.

   - Fix a problem where inline data pages weren't getting flushed
     during an unshare operation.

   - Rework iomap to support arbitrarily many blocks per page in
     preparation to support THP for the page cache.

   - Fix a bug in the blocksize < pagesize buffered io path where we
     could fail to initialize the many-blocks-per-page uptodate bitmap
     correctly when the backing page is actually up to date. This could
     cause us to forget to write out dirty pages.

   - Split out the generic_write_sync at the end of the directio write
     path so that btrfs can drop the inode lock before sync'ing the
     file.

   - Call inode_dio_end before trying to sync the file after a O_DSYNC
     direct write (instead of afterwards) to match the behavior of the
     old directio code"

* tag 'iomap-5.10-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: Call inode_dio_end() before generic_write_sync()
  iomap: Allow filesystem to call iomap_dio_complete without i_rwsem
  iomap: Set all uptodate bits for an Uptodate page
  iomap: Change calling convention for zeroing
  iomap: Convert iomap_write_end types
  iomap: Convert write_count to write_bytes_pending
  iomap: Convert read_count to read_bytes_pending
  iomap: Support arbitrarily many blocks per page
  iomap: Use bitmap ops to set uptodate bits
  iomap: Use kzalloc to allocate iomap_page
  fs: Introduce i_blocks_per_page
  iomap: Fix misplaced page flushing
  iomap: Use round_down/round_up macros in __iomap_write_begin
  iomap: Mark read blocks uptodate in write_begin
  iomap: Clear page error before beginning a write
  iomap: Fix direct I/O write consistency check
  iomap: fix WARN_ON_ONCE() from unprivileged users