Pull vfs fixes from Christian Brauner:
- Fix the AT_HANDLE_CONNECTABLE option so filesystems that don't know
how to decode a connected non-dir dentry fail the request
- Use repr(transparent) to ensure identical layout between the C and
Rust implementation of struct file
- Add a missing xas_pause() into the dax code employing
wait_entry_unlocked_exclusive()
- Fix FOP_DONTCACHE which we disabled for v6.15.
A folio could get redirtied and/or scheduled for writeback after the
initial dropbehind test. Change the test accordingly to handle these
cases so we can re-enable FOP_DONTCACHE again
* tag 'vfs-6.16-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
exportfs: require ->fh_to_parent() to encode connectable file handles
rust: file: improve safety comments
rust: file: mark `LocalFile` as `repr(transparent)`
fs/dax: Fix "don't skip locked entries when scanning entries"
iomap: don't lose folio dropbehind state for overwrites
mm/filemap: unify dropbehind flag testing and clearing
mm/filemap: unify read/write dropbehind naming
Revert "Disable FOP_DONTCACHE for now due to bugs"
mm/filemap: use filemap_end_dropbehind() for read invalidation
mm/filemap: gate dropbehind invalidate on folio !dirty && !writeback
Commit 6be3e21d25 ("fs/dax: don't skip locked entries when scanning
entries") introduced a new function, wait_entry_unlocked_exclusive(),
which waits for the current entry to become unlocked without advancing
the XArray iterator state.
Waiting for the entry to become unlocked requires dropping the XArray
lock. This requires calling xas_pause() prior to dropping the lock
which leaves the xas in a suitable state for the next iteration. However
this has the side-effect of advancing the xas state to the next index.
Normally this isn't an issue because xas_for_each() contains code to
detect this state and thus avoid advancing the index a second time on
the next loop iteration.
However both callers of and wait_entry_unlocked_exclusive() itself
subsequently use the xas state to reload the entry. As xas_pause()
updated the state to the next index this will cause the current entry
which is being waited on to be skipped. This caused the following
warning to fire intermittently when running xftest generic/068 on an XFS
filesystem with FS DAX enabled:
[ 35.067397] ------------[ cut here ]------------
[ 35.068229] WARNING: CPU: 21 PID: 1640 at mm/truncate.c:89 truncate_folio_batch_exceptionals+0xd8/0x1e0
[ 35.069717] Modules linked in: nd_pmem dax_pmem nd_btt nd_e820 libnvdimm
[ 35.071006] CPU: 21 UID: 0 PID: 1640 Comm: fstest Not tainted 6.15.0-rc7+ #77 PREEMPT(voluntary)
[ 35.072613] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/204
[ 35.074845] RIP: 0010:truncate_folio_batch_exceptionals+0xd8/0x1e0
[ 35.075962] Code: a1 00 00 00 f6 47 0d 20 0f 84 97 00 00 00 4c 63 e8 41 39 c4 7f 0b eb 61 49 83 c5 01 45 39 ec 7e 58 42 f68
[ 35.079522] RSP: 0018:ffffb04e426c7850 EFLAGS: 00010202
[ 35.080359] RAX: 0000000000000000 RBX: ffff9d21e3481908 RCX: ffffb04e426c77f4
[ 35.081477] RDX: ffffb04e426c79e8 RSI: ffffb04e426c79e0 RDI: ffff9d21e34816e8
[ 35.082590] RBP: ffffb04e426c79e0 R08: 0000000000000001 R09: 0000000000000003
[ 35.083733] R10: 0000000000000000 R11: 822b53c0f7a49868 R12: 000000000000001f
[ 35.084850] R13: 0000000000000000 R14: ffffb04e426c78e8 R15: fffffffffffffffe
[ 35.085953] FS: 00007f9134c87740(0000) GS:ffff9d22abba0000(0000) knlGS:0000000000000000
[ 35.087346] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 35.088244] CR2: 00007f9134c86000 CR3: 000000040afff000 CR4: 00000000000006f0
[ 35.089354] Call Trace:
[ 35.089749] <TASK>
[ 35.090168] truncate_inode_pages_range+0xfc/0x4d0
[ 35.091078] truncate_pagecache+0x47/0x60
[ 35.091735] xfs_setattr_size+0xc7/0x3e0
[ 35.092648] xfs_vn_setattr+0x1ea/0x270
[ 35.093437] notify_change+0x1f4/0x510
[ 35.094219] ? do_truncate+0x97/0xe0
[ 35.094879] do_truncate+0x97/0xe0
[ 35.095640] path_openat+0xabd/0xca0
[ 35.096278] do_filp_open+0xd7/0x190
[ 35.096860] do_sys_openat2+0x8a/0xe0
[ 35.097459] __x64_sys_openat+0x6d/0xa0
[ 35.098076] do_syscall_64+0xbb/0x1d0
[ 35.098647] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 35.099444] RIP: 0033:0x7f9134d81fc1
[ 35.100033] Code: 75 57 89 f0 25 00 00 41 00 3d 00 00 41 00 74 49 80 3d 2a 26 0e 00 00 74 6d 89 da 48 89 ee bf 9c ff ff ff5
[ 35.102993] RSP: 002b:00007ffcd41e0d10 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
[ 35.104263] RAX: ffffffffffffffda RBX: 0000000000000242 RCX: 00007f9134d81fc1
[ 35.105452] RDX: 0000000000000242 RSI: 00007ffcd41e1200 RDI: 00000000ffffff9c
[ 35.106663] RBP: 00007ffcd41e1200 R08: 0000000000000000 R09: 0000000000000064
[ 35.107923] R10: 00000000000001a4 R11: 0000000000000202 R12: 0000000000000066
[ 35.109112] R13: 0000000000100000 R14: 0000000000100000 R15: 0000000000000400
[ 35.110357] </TASK>
[ 35.110769] irq event stamp: 8415587
[ 35.111486] hardirqs last enabled at (8415599): [<ffffffff8d74b562>] __up_console_sem+0x52/0x60
[ 35.113067] hardirqs last disabled at (8415610): [<ffffffff8d74b547>] __up_console_sem+0x37/0x60
[ 35.114575] softirqs last enabled at (8415300): [<ffffffff8d6ac625>] handle_softirqs+0x315/0x3f0
[ 35.115933] softirqs last disabled at (8415291): [<ffffffff8d6ac811>] __irq_exit_rcu+0xa1/0xc0
[ 35.117316] ---[ end trace 0000000000000000 ]---
Fix this by using xas_reset() instead, which is equivalent in
implementation to xas_pause() but does not advance the XArray state.
Fixes: 6be3e21d25 ("fs/dax: don't skip locked entries when scanning entries")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Link: https://lore.kernel.org/20250523043749.1460780-1-apopple@nvidia.com
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: "Matthew Wilcow (Oracle)" <willy@infradead.org>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Alison reports an issue with fsdax when large extends end up using large
ZONE_DEVICE folios:
[ 417.796271] BUG: kernel NULL pointer dereference, address: 0000000000000b00
[ 417.796982] #PF: supervisor read access in kernel mode
[ 417.797540] #PF: error_code(0x0000) - not-present page
[ 417.798123] PGD 2a5c5067 P4D 2a5c5067 PUD 2a5c6067 PMD 0
[ 417.798690] Oops: Oops: 0000 [#1] SMP NOPTI
[ 417.799178] CPU: 5 UID: 0 PID: 1515 Comm: mmap Tainted: ...
[ 417.800150] Tainted: [O]=OOT_MODULE
[ 417.800583] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[ 417.801358] RIP: 0010:__lruvec_stat_mod_folio+0x7e/0x250
[ 417.801948] Code: ...
[ 417.803662] RSP: 0000:ffffc90002be3a08 EFLAGS: 00010206
[ 417.804234] RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000000002
[ 417.804984] RDX: ffffffff815652d7 RSI: 0000000000000000 RDI: ffffffff82a2beae
[ 417.805689] RBP: ffffc90002be3a28 R08: 0000000000000000 R09: 0000000000000000
[ 417.806384] R10: ffffea0007000040 R11: ffff888376ffe000 R12: 0000000000000001
[ 417.807099] R13: 0000000000000012 R14: ffff88807fe4ab40 R15: ffff888029210580
[ 417.807801] FS: 00007f339fa7a740(0000) GS:ffff8881fa9b9000(0000) knlGS:0000000000000000
[ 417.808570] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 417.809193] CR2: 0000000000000b00 CR3: 000000002a4f0004 CR4: 0000000000370ef0
[ 417.809925] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 417.810622] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 417.811353] Call Trace:
[ 417.811709] <TASK>
[ 417.812038] folio_add_file_rmap_ptes+0x143/0x230
[ 417.812566] insert_page_into_pte_locked+0x1ee/0x3c0
[ 417.813132] insert_page+0x78/0xf0
[ 417.813558] vmf_insert_page_mkwrite+0x55/0xa0
[ 417.814088] dax_fault_iter+0x484/0x7b0
[ 417.814542] dax_iomap_pte_fault+0x1ca/0x620
[ 417.815055] dax_iomap_fault+0x39/0x40
[ 417.815499] __xfs_write_fault+0x139/0x380
[ 417.815995] ? __handle_mm_fault+0x5e5/0x1a60
[ 417.816483] xfs_write_fault+0x41/0x50
[ 417.816966] xfs_filemap_fault+0x3b/0xe0
[ 417.817424] __do_fault+0x31/0x180
[ 417.817859] __handle_mm_fault+0xee1/0x1a60
[ 417.818325] ? debug_smp_processor_id+0x17/0x20
[ 417.818844] handle_mm_fault+0xe1/0x2b0
[...]
The issue is that when we split a large ZONE_DEVICE folio to order-0 ones,
we don't reset the order/_nr_pages. As folio->_nr_pages overlays
page[1]->memcg_data, once page[1] is a folio, it suddenly looks like it
has folio->memcg_data set. And we never manually initialize
folio->memcg_data in fsdax code, because we never expect it to be set at
all.
When __lruvec_stat_mod_folio() then stumbles over such a folio, it tries
to use folio->memcg_data (because it's non-NULL) but it does not actually
point at a memcg, resulting in the problem.
Alison also observed that these folios sometimes have "locked" set, which
is rather concerning (folios locked from the beginning ...). The reason
is that the order for large folios is stored in page[1]->flags, which
become the folio->flags of a new small folio.
Let's fix it by adding a folio helper to clear order/_nr_pages for
splitting purposes.
Maybe we should reinitialize other large folio flags / folio members as
well when splitting, because they might similarly cause harm once page[1]
becomes a folio? At least other flags in PAGE_FLAGS_SECOND should not be
set for fsdax, so at least page[1]->flags might be as expected with this
fix.
From a quick glimpse, initializing ->mapping, ->pgmap and ->share should
re-initialize most things from a previous page[1] used by large folios
that fsdax cares about. For example folio->private might not get
reinitialized, but maybe that's not relevant -- no traces of it's use in
fsdax code. Needs a closer look.
Another thing that should be considered in the future is performing
similar checks as we perform in free_tail_page_prepare()
-- checking pincount etc.
-- when freeing a large fsdax folio.
Link: https://lkml.kernel.org/r/20250410091020.119116-1-david@redhat.com
Fixes: 4996fc547f ("mm: let _folio_nr_pages overlay memcg_data in first tail page")
Fixes: 38607c62b3 ("fs/dax: properly refcount fs dax pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Alison Schofield <alison.schofield@intel.com>
Closes: https://lkml.kernel.org/r/Z_W9Oeg-D9FhImf3@aschofie-mobl2.lan
Tested-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: "Darrick J. Wong" <djwong@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull MM updates from Andrew Morton:
- The series "Enable strict percpu address space checks" from Uros
Bizjak uses x86 named address space qualifiers to provide
compile-time checking of percpu area accesses.
This has caused a small amount of fallout - two or three issues were
reported. In all cases the calling code was found to be incorrect.
- The series "Some cleanup for memcg" from Chen Ridong implements some
relatively monir cleanups for the memcontrol code.
- The series "mm: fixes for device-exclusive entries (hmm)" from David
Hildenbrand fixes a boatload of issues which David found then using
device-exclusive PTE entries when THP is enabled. More work is
needed, but this makes thins better - our own HMM selftests now
succeed.
- The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
remove the z3fold and zbud implementations. They have been deprecated
for half a year and nobody has complained.
- The series "mm: further simplify VMA merge operation" from Lorenzo
Stoakes implements numerous simplifications in this area. No runtime
effects are anticipated.
- The series "mm/madvise: remove redundant mmap_lock operations from
process_madvise()" from SeongJae Park rationalizes the locking in the
madvise() implementation. Performance gains of 20-25% were observed
in one MADV_DONTNEED microbenchmark.
- The series "Tiny cleanup and improvements about SWAP code" from
Baoquan He contains a number of touchups to issues which Baoquan
noticed when working on the swap code.
- The series "mm: kmemleak: Usability improvements" from Catalin
Marinas implements a couple of improvements to the kmemleak
user-visible output.
- The series "mm/damon/paddr: fix large folios access and schemes
handling" from Usama Arif provides a couple of fixes for DAMON's
handling of large folios.
- The series "mm/damon/core: fix wrong and/or useless damos_walk()
behaviors" from SeongJae Park fixes a few issues with the accuracy of
kdamond's walking of DAMON regions.
- The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
Stoakes changes the interaction between framebuffer deferred-io and
core MM. No functional changes are anticipated - this is preparatory
work for the future removal of page structure fields.
- The series "mm/damon: add support for hugepage_size DAMOS filter"
from Usama Arif adds a DAMOS filter which permits the filtering by
huge page sizes.
- The series "mm: permit guard regions for file-backed/shmem mappings"
from Lorenzo Stoakes extends the guard region feature from its
present "anon mappings only" state. The feature now covers shmem and
file-backed mappings.
- The series "mm: batched unmap lazyfree large folios during
reclamation" from Barry Song cleans up and speeds up the unmapping
for pte-mapped large folios.
- The series "reimplement per-vma lock as a refcount" from Suren
Baghdasaryan puts the vm_lock back into the vma. Our reasons for
pulling it out were largely bogus and that change made the code more
messy. This patchset provides small (0-10%) improvements on one
microbenchmark.
- The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
improves" from SeongJae Park does some maintenance work on the DAMON
docs.
- The series "hugetlb/CMA improvements for large systems" from Frank
van der Linden addresses a pile of issues which have been observed
when using CMA on large machines.
- The series "mm/damon: introduce DAMOS filter type for unmapped pages"
from SeongJae Park enables users of DMAON/DAMOS to filter my the
page's mapped/unmapped status.
- The series "zsmalloc/zram: there be preemption" from Sergey
Senozhatsky teaches zram to run its compression and decompression
operations preemptibly.
- The series "selftests/mm: Some cleanups from trying to run them" from
Brendan Jackman fixes a pile of unrelated issues which Brendan
encountered while runnimg our selftests.
- The series "fs/proc/task_mmu: add guard region bit to pagemap" from
Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
determine whether a particular page is a guard page.
- The series "mm, swap: remove swap slot cache" from Kairui Song
removes the swap slot cache from the allocation path - it simply
wasn't being effective.
- The series "mm: cleanups for device-exclusive entries (hmm)" from
David Hildenbrand implements a number of unrelated cleanups in this
code.
- The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
implements a number of preparatoty cleanups to the GENERIC_PTDUMP
Kconfig logic.
- The series "mm/damon: auto-tune aggregation interval" from SeongJae
Park implements a feedback-driven automatic tuning feature for
DAMON's aggregation interval tuning.
- The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
preparation for implementing lazy mmu mode for arm64 to optimize
vmalloc.
- The series "mm/page_alloc: Some clarifications for migratetype
fallback" from Brendan Jackman reworks some commentary to make the
code easier to follow.
- The series "page_counter cleanup and size reduction" from Shakeel
Butt cleans up the page_counter code and fixes a size increase which
we accidentally added late last year.
- The series "Add a command line option that enables control of how
many threads should be used to allocate huge pages" from Thomas
Prescher does that. It allows the careful operator to significantly
reduce boot time by tuning the parallalization of huge page
initialization.
- The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
from Tang Yizhou fixes the tracing output from the dirty page
balancing code.
- The series "mm/damon: make allow filters after reject filters useful
and intuitive" from SeongJae Park improves the handling of allow and
reject filters. Behaviour is made more consistent and the documention
is updated accordingly.
- The series "Switch zswap to object read/write APIs" from Yosry Ahmed
updates zswap to the new object read/write APIs and thus permits the
removal of some legacy code from zpool and zsmalloc.
- The series "Some trivial cleanups for shmem" from Baolin Wang does as
it claims.
- The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
Alistair Popple regularizes the weird ZONE_DEVICE page refcount
handling in DAX, permittig the removal of a number of special-case
checks.
- The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
preparatoty refactoring and cleanup of the mremap() code.
- The series "mm: MM owner tracking for large folios (!hugetlb) +
CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
which we determine whether a large folio is known to be mapped
exclusively into a single MM.
- The series "mm/damon: add sysfs dirs for managing DAMOS filters based
on handling layers" from SeongJae Park adds a couple of new sysfs
directories to ease the management of DAMON/DAMOS filters.
- The series "arch, mm: reduce code duplication in mem_init()" from
Mike Rapoport consolidates many per-arch implementations of
mem_init() into code generic code, where that is practical.
- The series "mm/damon/sysfs: commit parameters online via
damon_call()" from SeongJae Park continues the cleaning up of sysfs
access to DAMON internal data.
- The series "mm: page_ext: Introduce new iteration API" from Luiz
Capitulino reworks the page_ext initialization to fix a boot-time
crash which was observed with an unusual combination of compile and
cmdline options.
- The series "Buddy allocator like (or non-uniform) folio split" from
Zi Yan reworks the code to split a folio into smaller folios. The
main benefit is lessened memory consumption: fewer post-split folios
are generated.
- The series "Minimize xa_node allocation during xarry split" from Zi
Yan reduces the number of xarray xa_nodes which are generated during
an xarray split.
- The series "drivers/base/memory: Two cleanups" from Gavin Shan
performs some maintenance work on the drivers/base/memory code.
- The series "Add tracepoints for lowmem reserves, watermarks and
totalreserve_pages" from Martin Liu adds some more tracepoints to the
page allocator code.
- The series "mm/madvise: cleanup requests validations and
classifications" from SeongJae Park cleans up some warts which
SeongJae observed during his earlier madvise work.
- The series "mm/hwpoison: Fix regressions in memory failure handling"
from Shuai Xue addresses two quite serious regressions which Shuai
has observed in the memory-failure implementation.
- The series "mm: reliable huge page allocator" from Johannes Weiner
makes huge page allocations cheaper and more reliable by reducing
fragmentation.
- The series "Minor memcg cleanups & prep for memdescs" from Matthew
Wilcox is preparatory work for the future implementation of memdescs.
- The series "track memory used by balloon drivers" from Nico Pache
introduces a way to track memory used by our various balloon drivers.
- The series "mm/damon: introduce DAMOS filter type for active pages"
from Nhat Pham permits users to filter for active/inactive pages,
separately for file and anon pages.
- The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
separates the proactive reclaim statistics from the direct reclaim
statistics.
- The series "mm/vmscan: don't try to reclaim hwpoison folio" from
Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
code.
* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
x86/mm: restore early initialization of high_memory for 32-bits
mm/vmscan: don't try to reclaim hwpoison folio
mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
selftests/mm: speed up split_huge_page_test
selftests/mm: uffd-unit-tests support for hugepages > 2M
docs/mm/damon/design: document active DAMOS filter type
mm/damon: implement a new DAMOS filter type for active pages
fs/dax: don't disassociate zero page entries
MM documentation: add "Unaccepted" meminfo entry
selftests/mm: add commentary about 9pfs bugs
fork: use __vmalloc_node() for stack allocation
docs/mm: Physical Memory: Populate the "Zones" section
xen: balloon: update the NR_BALLOON_PAGES state
hv_balloon: update the NR_BALLOON_PAGES state
balloon_compaction: update the NR_BALLOON_PAGES state
meminfo: add a per node counter for balloon drivers
mm: remove references to folio in __memcg_kmem_uncharge_page()
...
Various iomap_iter_advance() calls advance by the full mapping
length and thus have no need for the current length input or
post-advance remaining length output from the standard advance
function. Add an iomap_iter_advance_full() helper to clean up these
cases.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/r/20250224144757.237706-13-bfoster@redhat.com
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The iter.processed field name is no longer appropriate now that
iomap operations do not return the number of bytes processed. Rename
the field to iter.status to reflect that a success or error code is
expected.
Also change the type to int as there is no longer a need for an s64.
This reduces the size of iomap_iter by 8 bytes due to a combination
of smaller type and reduction in structure padding. While here, fix
up the return types of various _iter() helpers to reflect the type
change.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/r/20250224144757.237706-12-bfoster@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Advance the iter on successful dedupe. Dedupe range uses two iters
and iterates so long as both have outstanding work, so
correspondingly this needs to advance both on each iteration. Since
dax_range_compare_iter() now returns status instead of a byte count,
update the variable name in the caller as well.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/r/20250224144757.237706-9-bfoster@redhat.com
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
DAX read and write currently advances the iter after the
dax_iomap_iter() returns the number of bytes processed rather than
internally within the iter handler itself, as most other iomap
operations do. Push the advance down into dax_iomap_iter() and
update the function to return op status instead of bytes processed.
dax_iomap_iter() shortcuts reads from a hole or unwritten mapping by
directly zeroing the iov_iter, so advance the iomap_iter similarly
in that case.
The DAX processing loop can operate on a range slightly different
than defined by the iomap_iter depending on circumstances. For
example, a read may be truncated by inode size, a read or write
range can be increased due to page alignment, etc. Therefore, this
patch aims to retain as much of the existing logic as possible.
The loop control logic remains pos based, but is sampled from the
iomap_iter on each iteration after the advance instead of being
updated manually. Similarly, length is updated based on the output
of the advance instead of being updated manually. The advance itself
is based on the number of bytes transferred, which was previously
used to update the local copies of pos and length.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/r/20250224144757.237706-6-bfoster@redhat.com
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
DAX reads and writes flow through dax_iomap_iter(), which has one or
more subtleties in terms of how it processes a range vs. what is
specified in the iomap_iter. To keep things simple and remove the
dependency on iomap_iter() advances, convert a positive return from
dax_iomap_iter() to the new advance and status return semantics. The
advance can be pushed further down in future patches.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/r/20250224144757.237706-5-bfoster@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The code that copies data from srcmap to iomap in dax_unshare_iter is
very very broken, which bfoster's recent fsx changes have exposed.
If the pos and len passed to dax_file_unshare are not aligned to an
fsblock boundary, the iter pos and length in the _iter function will
reflect this unalignment.
dax_iomap_direct_access always returns a pointer to the start of the
kmapped fsdax page, even if its pos argument is in the middle of that
page. This is catastrophic for data integrity when iter->pos is not
aligned to a page, because daddr/saddr do not point to the same byte in
the file as iter->pos. Hence we corrupt user data by copying it to the
wrong place.
If iter->pos + iomap_length() in the _iter function not aligned to a
page, then we fail to copy a full block, and only partially populate the
destination block. This is catastrophic for data confidentiality
because we expose stale pmem contents.
Fix both of these issues by aligning copy_pos/copy_len to a page
boundary (remember, this is fsdax so 1 fsblock == 1 base page) so that
we always copy full blocks.
We're not done yet -- there's no call to invalidate_inode_pages2_range,
so programs that have the file range mmap'd will continue accessing the
old memory mapping after the file metadata updates have completed.
Be careful with the return value -- if the unshare succeeds, we still
need to return the number of bytes that the iomap iter thinks we're
operating on.
Cc: ruansy.fnst@fujitsu.com
Fixes: d984648e42 ("fsdax,xfs: port unshare to fsdax")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/172796813328.1131942.16777025316348797355.stgit@frogsfrogsfrogs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Remove the code in dax_unshare_iter that zeroes the destination memory
because it's not necessary.
If srcmap is unwritten, we don't have to do anything because that
unwritten extent came from the regular file mapping, and unwritten
extents cannot be shared. The same applies to holes.
Furthermore, zeroing to unshare a mapping is just plain wrong because
unsharing means copy on write, and we should be copying data.
This is effectively a revert of commit 13dd4e0462 ("fsdax: unshare:
zero destination if srcmap is HOLE or UNWRITTEN")
Cc: ruansy.fnst@fujitsu.com
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/172796813311.1131942.16033376284752798632.stgit@frogsfrogsfrogs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The predicate code that iomap_unshare_iter uses to decide if it's really
needs to unshare a file range mapping should be shared with the fsdax
version, because right now they're opencoded and inconsistent.
Note that we simplify the predicate logic a bit -- we no longer allow
unsharing of inline data mappings, but there aren't any filesystems that
allow shared inline data currently.
This is a fix in the sense that it should have been ported to fsdax.
Fixes: b53fdb215d ("iomap: improve shared block detection in iomap_unshare_iter")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/172796813294.1131942.15762084021076932620.stgit@frogsfrogsfrogs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Remove the unnecessary encoding of page order into an enum and pass the
page order directly. That lets us get rid of pe_order().
The switch constructs have to be changed to if/else constructs to prevent
GCC from warning on builds with 3-level page tables where PMD_ORDER and
PUD_ORDER have the same value.
If you are looking at this commit because your driver stopped compiling,
look at the previous commit as well and audit your driver to be sure it
doesn't depend on mmap_lock being held in its ->huge_fault method.
[willy@infradead.org: use "order %u" to match the (non dev_t) style]
Link: https://lkml.kernel.org/r/ZOUYekbtTv+n8hYf@casper.infradead.org
Link: https://lkml.kernel.org/r/20230818202335.2739663-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Change calling convention for ->huge_fault", v2.
There are two unrelated changes to the calling convention for
->huge_fault. I've bundled them together to help people notice the
change. The first is to improve scalability of DAX page faults by
allowing them to be handled under the VMA lock. The second is to remove
enum page_entry_size since it's really unnecessary. The changelogs and
documentation updates hopefully work to that end.
This patch (of 3):
Allow this to be used in generic code. Also add PUD_ORDER.
Link: https://lkml.kernel.org/r/20230818202335.2739663-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230818202335.2739663-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When multiple processes mmap() a dax file, then at some point,
a process issues a 'load' and consumes a hwpoison, the process
receives a SIGBUS with si_code = BUS_MCEERR_AR and with si_lsb
set for the poison scope. Soon after, any other process issues
a 'load' to the poisoned page (that is unmapped from the kernel
side by memory_failure), it receives a SIGBUS with
si_code = BUS_ADRERR and without valid si_lsb.
This is confusing to user, and is different from page fault due
to poison in RAM memory, also some helpful information is lost.
Channel dax backend driver's poison detection to the filesystem
such that instead of reporting VM_FAULT_SIGBUS, it could report
VM_FAULT_HWPOISON.
If user level block IO syscalls fail due to poison, the errno will
be converted to EIO to maintain block API consistency.
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Link: https://lore.kernel.org/r/20230615181325.1327259-2-jane.chu@oracle.com
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
The variable 'error' is being assigned a value that is never read,
the assignment and the variable and redundant and can be removed.
Cleans up clang scan build warning:
fs/dax.c:1880:10: warning: Although the value stored to 'error' is
used in the enclosing expression, the value is never actually read
from 'error' [deadcode.DeadStores]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20230621130256.2676126-1-colin.i.king@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
In an dedupe comparison iter loop, the length of iomap_iter decreases
because it implies the remaining length after each iteration.
The dedupe command will fail with -EIO if the range is larger than one
page size and not aligned to the page size. Also report warning in dmesg:
[ 4338.498374] ------------[ cut here ]------------
[ 4338.498689] WARNING: CPU: 3 PID: 1415645 at fs/iomap/iter.c:16
...
The compare function should use the min length of the current iters,
not the total length.
Link: https://lkml.kernel.org/r/1679469958-2-1-git-send-email-ruansy.fnst@fujitsu.com
Fixes: 0e79e3736d ("fsdax: dedupe: iter two files at the same time")
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "fsdax,xfs: fix warning messages", v2.
Many testcases failed in dax+reflink mode with warning message in dmesg.
Such as generic/051,075,127. The warning message is like this:
[ 775.509337] ------------[ cut here ]------------
[ 775.509636] WARNING: CPU: 1 PID: 16815 at fs/dax.c:386 dax_insert_entry.cold+0x2e/0x69
[ 775.510151] Modules linked in: auth_rpcgss oid_registry nfsv4 algif_hash af_alg af_packet nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables nfnetlink ip6table_filter ip6_tables iptable_filter ip_tables x_tables dax_pmem nd_pmem nd_btt sch_fq_codel configfs xfs libcrc32c fuse
[ 775.524288] CPU: 1 PID: 16815 Comm: fsx Kdump: loaded Tainted: G W 6.1.0-rc4+ #164 eb34e4ee4200c7cbbb47de2b1892c5a3e027fd6d
[ 775.524904] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Arch Linux 1.16.0-3-3 04/01/2014
[ 775.525460] RIP: 0010:dax_insert_entry.cold+0x2e/0x69
[ 775.525797] Code: c7 c7 18 eb e0 81 48 89 4c 24 20 48 89 54 24 10 e8 73 6d ff ff 48 83 7d 18 00 48 8b 54 24 10 48 8b 4c 24 20 0f 84 e3 e9 b9 ff <0f> 0b e9 dc e9 b9 ff 48 c7 c6 a0 20 c3 81 48 c7 c7 f0 ea e0 81 48
[ 775.526708] RSP: 0000:ffffc90001d57b30 EFLAGS: 00010082
[ 775.527042] RAX: 000000000000002a RBX: 0000000000000000 RCX: 0000000000000042
[ 775.527396] RDX: ffffea000a0f6c80 RSI: ffffffff81dfab1b RDI: 00000000ffffffff
[ 775.527819] RBP: ffffea000a0f6c40 R08: 0000000000000000 R09: ffffffff820625e0
[ 775.528241] R10: ffffc90001d579d8 R11: ffffffff820d2628 R12: ffff88815fc98320
[ 775.528598] R13: ffffc90001d57c18 R14: 0000000000000000 R15: 0000000000000001
[ 775.528997] FS: 00007f39fc75d740(0000) GS:ffff88817bc80000(0000) knlGS:0000000000000000
[ 775.529474] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 775.529800] CR2: 00007f39fc772040 CR3: 0000000107eb6001 CR4: 00000000003706e0
[ 775.530214] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 775.530592] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 775.531002] Call Trace:
[ 775.531230] <TASK>
[ 775.531444] dax_fault_iter+0x267/0x6c0
[ 775.531719] dax_iomap_pte_fault+0x198/0x3d0
[ 775.532002] __xfs_filemap_fault+0x24a/0x2d0 [xfs aa8d25411432b306d9554da38096f4ebb86bdfe7]
[ 775.532603] __do_fault+0x30/0x1e0
[ 775.532903] do_fault+0x314/0x6c0
[ 775.533166] __handle_mm_fault+0x646/0x1250
[ 775.533480] handle_mm_fault+0xc1/0x230
[ 775.533810] do_user_addr_fault+0x1ac/0x610
[ 775.534110] exc_page_fault+0x63/0x140
[ 775.534389] asm_exc_page_fault+0x22/0x30
[ 775.534678] RIP: 0033:0x7f39fc55820a
[ 775.534950] Code: 00 01 00 00 00 74 99 83 f9 c0 0f 87 7b fe ff ff c5 fe 6f 4e 20 48 29 fe 48 83 c7 3f 49 8d 0c 10 48 83 e7 c0 48 01 fe 48 29 f9 <f3> a4 c4 c1 7e 7f 00 c4 c1 7e 7f 48 20 c5 f8 77 c3 0f 1f 44 00 00
[ 775.535839] RSP: 002b:00007ffc66a08118 EFLAGS: 00010202
[ 775.536157] RAX: 00007f39fc772001 RBX: 0000000000042001 RCX: 00000000000063c1
[ 775.536537] RDX: 0000000000006400 RSI: 00007f39fac42050 RDI: 00007f39fc772040
[ 775.536919] RBP: 0000000000006400 R08: 00007f39fc772001 R09: 0000000000042000
[ 775.537304] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000001
[ 775.537694] R13: 00007f39fc772000 R14: 0000000000006401 R15: 0000000000000003
[ 775.538086] </TASK>
[ 775.538333] ---[ end trace 0000000000000000 ]---
This also affects dax+noreflink mode if we run the test after a
dax+reflink test. So, the most urgent thing is solving the warning
messages.
With these fixes, most warning messages in dax_associate_entry() are gone.
But honestly, generic/388 will randomly failed with the warning. The
case shutdown the xfs when fsstress is running, and do it for many times.
I think the reason is that dax pages in use are not able to be invalidated
in time when fs is shutdown. The next time dax page to be associated, it
still remains the mapping value set last time. I'll keep on solving it.
The warning message in dax_writeback_one() can also be fixed because of
the dax unshare.
This patch (of 8):
fsdax page is used not only when CoW, but also mapread. To make the it
easily understood, use 'share' to indicate that the dax page is shared by
more than one extent. And add helper functions to use it.
Also, the flag needs to be renamed to PAGE_MAPPING_DAX_SHARED.
[ruansy.fnst@fujitsu.com: rename several functions]
Link: https://lkml.kernel.org/r/1669972991-246-1-git-send-email-ruansy.fnst@fujitsu.com
[ruansy.fnst@fujitsu.com: v2.2]
Link: https://lkml.kernel.org/r/1670381359-53-1-git-send-email-ruansy.fnst@fujitsu.com
Link: https://lkml.kernel.org/r/1669908538-55-1-git-send-email-ruansy.fnst@fujitsu.com
Link: https://lkml.kernel.org/r/1669908538-55-2-git-send-email-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
I got an infinite loop and a WARNING report when executing a tail command
in virtiofs.
WARNING: CPU: 10 PID: 964 at fs/iomap/iter.c:34 iomap_iter+0x3a2/0x3d0
Modules linked in:
CPU: 10 PID: 964 Comm: tail Not tainted 5.19.0-rc7
Call Trace:
<TASK>
dax_iomap_rw+0xea/0x620
? __this_cpu_preempt_check+0x13/0x20
fuse_dax_read_iter+0x47/0x80
fuse_file_read_iter+0xae/0xd0
new_sync_read+0xfe/0x180
? 0xffffffff81000000
vfs_read+0x14d/0x1a0
ksys_read+0x6d/0xf0
__x64_sys_read+0x1a/0x20
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The tail command will call read() with a count of 0. In this case,
iomap_iter() will report this WARNING, and always return 1 which casuing
the infinite loop in dax_iomap_rw().
Fixing by checking count whether is 0 in dax_iomap_rw().
Fixes: ca289e0b95 ("fsdax: switch dax_iomap_rw to use iomap_iter")
Signed-off-by: Li Jinlin <lijinlin3@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220725032050.3873372-1-lijinlin3@huawei.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
