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try_lookup_one_len() is identical to lookup_one_unlocked() except that
it doesn't include the call to lookup_slow(). The latter doesn't need
the inode to be locked, so the former cannot either.
So fix the documentation, remove the WARN_ON and fix the only caller to
not take the lock.
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/174190517441.9342.5956460781380903128@noble.neil.brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
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No functional changes.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250313142744.1323281-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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... except when the table is known to be only used by one thread.
A file pointer can get installed at any moment despite the ->file_lock
being held since the following:
8a81252b774b53e6 ("fs/file.c: don't acquire files->file_lock in fd_install()")
Accesses subject to such a race can in principle suffer load tearing.
While here redo the comment in dup_fd -- it only covered a race against
files showing up, still assuming fd_install() takes the lock.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250313135725.1320914-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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No callers passes flags to xfs_buf_get_uncached, which makes sense
given that the flags apply to behavior not used for uncached buffers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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No callers passes flags to xfs_buf_read_uncached, which makes sense
given that the flags apply to behavior not used for uncached buffers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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xfs_buf_free_maps only has a single caller, so open code it there. Stop
zeroing the b_maps pointer as the buffer is freed in the next line.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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xfs_buf_get_maps has a single caller, and can just be open coded there.
When doing that, stop handling the allocation failure as we always pass
__GFP_NOFAIL to the slab allocator, and use the proper kcalloc helper for
array allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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We never allocate a buffer without backing memory. Simplify the call
chain by calling xfs_buf_alloc_backing_mem from _xfs_buf_alloc. To
avoid a forward declaration, move _xfs_buf_alloc down a bit in the
file.
Also drop the pointless _-prefix from _xfs_buf_alloc.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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Remove unnecessary NULL check before kvfree() reported by
Coccinelle/coccicheck and the semantic patch at
scripts/coccinelle/free/ifnullfree.cocci.
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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Merge buffer cache conversion to folios and vmalloc
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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Merge Zoned allocator for XFS.
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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Since commit e1fa9ea85ce8 ("gfs2: Stop using glock holder auto-demotion
for now"), we unconditionally drop the inode glock before trying to
fault in more pages.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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xfs_zoned_wake_all checks SB_ACTIVE to make sure it does the right thing
when a shutdown happens during unmount, but it fails to account for the
log recovery special case that sets SB_ACTIVE temporarily. Add a NULL
check to cover both cases.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
[hch: added a commit log and comment]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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xfs_growfs_data needs to increment m_generation as soon as the primary
superblock has been updated. As the update of the secondary superblocks
was part of xfs_growfs_data_private that mean the incremented had to be
done unconditionally once that was called. Later, commit 83a7f86e39ff
("xfs: separate secondary sb update in growfs") split the secondary
superblock update into a separate helper, so now the increment on error
can be limited to failed calls to xfs_update_secondary_sbs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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The newly added check for the internal RT device needs to unlock
m_growlock just like all ther other error cases.
Fixes: bdc03eb5f98f ("xfs: allow internal RT devices for zoned mode")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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Some file systems (e.g. ext4) may reuse inode numbers once the inode is
not in use anymore. Usually hostfs will keep an FD open for each inode,
but this is not always the case. In the case of sockets, this cannot
even be done properly.
As such, the following sequence of events was possible:
* application creates and deletes a socket
* hostfs creates/deletes the socket on the host
* inode is still in the hostfs cache
* hostfs creates a new file
* ext4 on the outside reuses the inode number
* hostfs finds the socket inode for the newly created file
* application receives -ENXIO when opening the file
As mentioned, this can only happen if the deleted file is a special file
that is never opened on the host (i.e. no .open fop).
As such, to prevent issues, it is sufficient to check that the inode
has the expected type. That said, also add a check for the inode birth
time, just to be on the safe side.
Fixes: 74ce793bcbde ("hostfs: Fix ephemeral inodes")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Mickaël Salaün <mic@digikod.net>
Tested-by: Mickaël Salaün <mic@digikod.net>
Link: https://patch.msgid.link/20250214092822.1241575-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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LSMs often inspect the path.mnt of files in the security hooks, and this
causes a NULL deref in efivarfs_pm_notify() because the path is
constructed with a NULL path.mnt.
Fix by obtaining from vfs_kern_mount() instead, and being very careful
to ensure that deactivate_super() (potentially triggered by a racing
userspace umount) is not called directly from the notifier, because it
would deadlock when efivarfs_kill_sb() tried to unregister the notifier
chain.
[ Al notes:
Umm... That's probably safe, but not as a long-term solution -
it's too intimately dependent upon fs/super.c internals. The
reasons why you can't run into ->s_umount deadlock here are
non-trivial... ]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Link: https://lore.kernel.org/r/e54e6a2f-1178-4980-b771-4d9bafc2aa47@tnxip.de
Link: https://lore.kernel.org/r/3e998bf87638a442cbc6864cdcd3d8d9e08ce3e3.camel@HansenPartnership.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc hotfixes from Andrew Morton:
"15 hotfixes. 7 are cc:stable and the remainder address post-6.13
issues or aren't considered necessary for -stable kernels.
13 are for MM and the other two are for squashfs and procfs.
All are singletons. Please see the individual changelogs for details"
* tag 'mm-hotfixes-stable-2025-03-17-20-09' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/page_alloc: fix memory accept before watermarks gets initialized
mm: decline to manipulate the refcount on a slab page
memcg: drain obj stock on cpu hotplug teardown
mm/huge_memory: drop beyond-EOF folios with the right number of refs
selftests/mm: run_vmtests.sh: fix half_ufd_size_MB calculation
mm: fix error handling in __filemap_get_folio() with FGP_NOWAIT
mm: memcontrol: fix swap counter leak from offline cgroup
mm/vma: do not register private-anon mappings with khugepaged during mmap
squashfs: fix invalid pointer dereference in squashfs_cache_delete
mm/migrate: fix shmem xarray update during migration
mm/hugetlb: fix surplus pages in dissolve_free_huge_page()
mm/damon/core: initialize damos->walk_completed in damon_new_scheme()
mm/damon: respect core layer filters' allowance decision on ops layer
filemap: move prefaulting out of hot write path
proc: fix UAF in proc_get_inode()
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Remove a use of folio->page by passing the folio into
adjust_range_hwpoison(). We need to convert to a page eventually, but
that can happen inside adjust_range_hwpoison().
Link: https://lkml.kernel.org/r/20250226163131.3795869-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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pte_page() is more expensive than pte_pfn() (often it's defined as
pfn_to_page(pte_pfn())), so it makes sense to do the conversion to pfn
once (by calling folio_pfn()) rather than convert the pfn to a page each
time.
While this is a very small advantage, the main motivation is removing a
reference to folio->page.
Link: https://lkml.kernel.org/r/20250226163131.3795869-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
When computing the output for smaps / smaps_rollups, in particular when
calculating the USS (Unique Set Size) and the PSS (Proportional Set Size),
we still rely on per-page mapcounts.
To determine private vs. shared, we'll use folio_likely_mapped_shared(),
similar to how we handle PM_MMAP_EXCLUSIVE. Similarly, we might now
under-estimate the USS and count pages towards "shared" that are actually
"private" ("exclusively mapped").
When calculating the PSS, we'll now also use the average per-page mapcount
for large folios: this can result in both, an over-estimation and an
under-estimation of the PSS. The difference is not expected to matter
much in practice, but we'll have to learn as we go.
We can now provide folio_precise_page_mapcount() only with
CONFIG_PAGE_MAPCOUNT, and remove one of the last users of per-page
mapcounts when CONFIG_NO_PAGE_MAPCOUNT is enabled.
Document the new behavior.
Link: https://lkml.kernel.org/r/20250303163014.1128035-20-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
For calculating "mapmax", we now use the average per-page mapcount in a
large folio instead of the per-page mapcount.
For hugetlb folios and folios that are not partially mapped into MMs,
there is no change.
Likely, this change will not matter much in practice, and an alternative
might be to simple remove this stat with CONFIG_NO_PAGE_MAPCOUNT.
However, there might be value to it, so let's keep it like that and
document the behavior.
Link: https://lkml.kernel.org/r/20250303163014.1128035-19-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
PM_MMAP_EXCLUSIVE will now be set if folio_likely_mapped_shared() is true
-- when the folio is considered "mapped shared", including when it once
was "mapped shared" but no longer is, as documented.
This might result in and under-indication of "exclusively mapped", which
is considered better than over-indicating it: under-estimating the USS
(Unique Set Size) is better than over-estimating it.
As an alternative, we could simply remove that flag with
CONFIG_NO_PAGE_MAPCOUNT completely, but there might be value to it. So,
let's keep it like that and document the behavior.
Link: https://lkml.kernel.org/r/20250303163014.1128035-18-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
For large folios, we'll return the per-page average mapcount within the
folio, whereby we round to the closest integer when calculating the
average: however, we'll always return at least 1 if the folio is mapped.
So assuming a folio with 512 pages, the average would be:
* 0 if not pages are mapped
* 1 if there are 1 .. 767 per-page mappings
* 2 if there are 767 .. 1279 per-page mappings
...
For hugetlb folios and for large folios that are fully mapped into all
address spaces, there is no change.
We'll make use of this helper in other context next.
As an alternative, we could simply return 0 for non-hugetlb large folios,
or disable this legacy interface with CONFIG_NO_PAGE_MAPCOUNT.
But the information exposed by this interface can still be valuable, and
frequently we deal with fully-mapped large folios where the average
corresponds to the actual page mapcount. So we'll leave it like this for
now and document the new behavior.
Note: this interface is likely not very relevant for performance. If ever
required, we could try doing a rather expensive rmap walk to collect
precisely how often this folio page is mapped.
Link: https://lkml.kernel.org/r/20250303163014.1128035-17-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Let's reuse our new MM ownership tracking infrastructure for large folios
to make folio_likely_mapped_shared() never return false negatives -- never
indicating "not mapped shared" although the folio *is* mapped shared.
With that, we can rename it to folio_maybe_mapped_shared() and get rid of
the dependency on the mapcount of the first folio page.
The semantics are now arguably clearer: no mixture of "false negatives"
and "false positives", only the remaining possibility for "false
positives".
Thoroughly document the new semantics. We might now detect that a large
folio is "maybe mapped shared" although it *no longer* is -- but once was.
Now, if more than two MMs mapped a folio at the same time, and the MM
mapping the folio exclusively at the end is not one tracked in the two
folio MM slots, we will detect the folio as "maybe mapped shared".
For anonymous folios, usually (except weird corner cases) all PTEs that
target a "maybe mapped shared" folio are R/O. As soon as a child process
would write to them (iow, actively use them), we would CoW and effectively
replace these PTEs. Most cases (below) are not expected to really matter
with large anonymous folios for this reason.
Most importantly, there will be no change at all for:
* small folios
* hugetlb folios
* PMD-mapped PMD-sized THPs (single mapping)
This change has the potential to affect existing callers of
folio_likely_mapped_shared() -> folio_maybe_mapped_shared():
(1) fs/proc/task_mmu.c: no change (hugetlb)
(2) khugepaged counts PTEs that target shared folios towards
max_ptes_shared (default: HPAGE_PMD_NR / 2), meaning we could skip a
collapse where we would have previously collapsed. This only applies
to anonymous folios and is not expected to matter in practice.
Worth noting that this change sorts out case (A) documented in
commit 1bafe96e89f0 ("mm/khugepaged: replace page_mapcount() check by
folio_likely_mapped_shared()") by removing the possibility for "false
negatives".
(3) MADV_COLD / MADV_PAGEOUT / MADV_FREE will not try splitting
PTE-mapped THPs that are considered shared but not fully covered by
the requested range, consequently not processing them.
PMD-mapped PMD-sized THP are not affected, or when all PTEs are
covered. These functions are usually only called on anon/file folios
that are exclusively mapped most of the time (no other file mappings
or no fork()), so the "false negatives" are not expected to matter in
practice.
(4) mbind() / migrate_pages() / move_pages() will refuse to migrate
shared folios unless MPOL_MF_MOVE_ALL is effective (requires
CAP_SYS_NICE). We will now reject some folios that could be migrated.
Similar to (3), especially with MPOL_MF_MOVE_ALL, so this is not
expected to matter in practice.
Note that cpuset_migrate_mm_workfn() calls do_migrate_pages() with
MPOL_MF_MOVE_ALL.
(5) NUMA hinting
mm/migrate.c:migrate_misplaced_folio_prepare() will skip file
folios that are probably shared libraries (-> "mapped shared" and
executable). This check would have detected it as a shared library at
some point (at least 3 MMs mapping it), so detecting it afterwards
does not sound wrong (still a shared library). Not expected to
matter.
mm/memory.c:numa_migrate_check() will indicate TNF_SHARED in
MAP_SHARED file mappings when encountering a shared folio. Similar
reasoning, not expected to matter.
mm/mprotect.c:change_pte_range() will skip folios detected as
shared in CoW mappings. Similarly, this is not expected to matter in
practice, but if it would ever be a problem we could relax that check
a bit (e.g., basing it on the average page-mapcount in a folio),
because it was only an optimization when many (e.g., 288) processes
were mapping the same folios -- see commit 859d4adc3415 ("mm: numa: do
not trap faults on shared data section pages.")
(6) mm/rmap.c:folio_referenced_one() will skip exclusive swapbacked
folios in dying processes. Applies to anonymous folios only. Without
"false negatives", we'll now skip all actually shared ones. Skipping
ones that are actually exclusive won't really matter, it's a pure
optimization, and is not expected to matter in practice.
In theory, one can detect the problematic scenario: folio_mapcount() > 0
and no folio MM slot is occupied ("state unknown"). One could reset the
MM slots while doing an rmap walk, which migration / folio split already
do when setting everything up. Further, when batching PTEs we might
naturally learn about a owner (e.g., folio_mapcount() == nr_ptes) and
could update the owner. However, we'll defer that until the scenarios
where it would really matter are clear.
Link: https://lkml.kernel.org/r/20250303163014.1128035-15-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently fs dax pages are considered free when the refcount drops to one
and their refcounts are not increased when mapped via PTEs or decreased
when unmapped. This requires special logic in mm paths to detect that
these pages should not be properly refcounted, and to detect when the
refcount drops to one instead of zero.
On the other hand get_user_pages(), etc. will properly refcount fs dax
pages by taking a reference and dropping it when the page is unpinned.
Tracking this special behaviour requires extra PTE bits (eg. pte_devmap)
and introduces rules that are potentially confusing and specific to FS DAX
pages. To fix this, and to possibly allow removal of the special PTE bits
in future, convert the fs dax page refcounts to be zero based and instead
take a reference on the page each time it is mapped as is currently the
case for normal pages.
This may also allow a future clean-up to remove the pgmap refcounting that
is currently done in mm/gup.c.
Link: https://lkml.kernel.org/r/c7d886ad7468a20452ef6e0ddab6cfe220874e7c.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The page ->mapping pointer can have magic values like
PAGE_MAPPING_DAX_SHARED and PAGE_MAPPING_ANON for page owner specific
usage. Currently PAGE_MAPPING_DAX_SHARED and PAGE_MAPPING_ANON alias to
the same value. This isn't a problem because FS DAX pages are never seen
by the anonymous mapping code and vice versa.
However a future change will make FS DAX pages more like normal pages, so
folio_test_anon() must not return true for a FS DAX page.
We could explicitly test for a FS DAX page in folio_test_anon(), etc.
however the PAGE_MAPPING_DAX_SHARED flag isn't actually needed. Instead
we can use the page->mapping field to implicitly track the first mapping
of a page. If page->mapping is non-NULL it implies the page is associated
with a single mapping at page->index. If the page is associated with a
second mapping clear page->mapping and set page->share to 1.
This is possible because a shared mapping implies the file-system
implements dax_holder_operations which makes the ->mapping and ->index,
which is a union with ->share, unused.
The page is considered shared when page->mapping == NULL and page->share >
0 or page->mapping != NULL, implying it is present in at least one address
space. This also makes it easier for a future change to detect when a
page is first mapped into an address space which requires special
handling.
Link: https://lkml.kernel.org/r/c22f699202db0acee2f7039eb026e68261ce42d6.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Dan Wiliams <dan.j.williams@intel.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
File systems call dax_break_mapping() prior to reallocating file system
blocks to ensure the page is not undergoing any DMA or other accesses.
Generally this is needed when a file is truncated to ensure that if a
block is reallocated nothing is writing to it. However filesystems
currently don't call this when an FS DAX inode is evicted.
This can cause problems when the file system is unmounted as a page can
continue to be under going DMA or other remote access after unmount. This
means if the file system is remounted any truncate or other operation
which requires the underlying file system block to be freed will not wait
for the remote access to complete. Therefore a busy block may be
reallocated to a new file leading to corruption.
Link: https://lkml.kernel.org/r/2d3cf575bbd095084993154be2f0aa7442e5cd28.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Dan Wiliams <dan.j.williams@intel.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Prior to any truncation operations file systems call dax_break_mapping()
to ensure pages in the range are not under going DMA. Later DAX
page-cache entries will be removed by truncate_folio_batch_exceptionals()
in the generic page-cache code.
However this makes it possible for folios to be removed from the
page-cache even though they are still DMA busy if the file-system hasn't
called dax_break_mapping(). It also means they can never be waited on in
future because FS DAX will lose track of them once the page-cache entry
has been deleted.
Instead it is better to delete the FS DAX entry when the file-system calls
dax_break_mapping() as part of it's truncate operation. This ensures only
idle pages can be removed from the FS DAX page-cache and makes it easy to
detect if a file-system hasn't called dax_break_mapping() prior to a
truncate operation.
Link: https://lkml.kernel.org/r/3be6115eaaa8d28fee37fcba3287be4f226a7d24.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Prior to freeing a block file systems supporting FS DAX must check that
the associated pages are both unmapped from user-space and not undergoing
DMA or other access from eg. get_user_pages(). This is achieved by
unmapping the file range and scanning the FS DAX page-cache to see if any
pages within the mapping have an elevated refcount.
This is done using two functions - dax_layout_busy_page_range() which
returns a page to wait for the refcount to become idle on. Rather than
open-code this introduce a common implementation to both unmap and wait
for the page to become idle.
Link: https://lkml.kernel.org/r/c4d381e41fc618296cee2820403c166d80599d5c.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
A FS DAX page is considered idle when its refcount drops to one. This is
currently open-coded in all file systems supporting FS DAX. Move the idle
detection to a common function to make future changes easier.
Link: https://lkml.kernel.org/r/c2c9d269110b90224eeb1dc661ffbc1d82aa20c9.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Several functions internal to FS DAX use the following pattern when trying
to obtain an unlocked entry:
xas_for_each(&xas, entry, end_idx) {
if (dax_is_locked(entry))
entry = get_unlocked_entry(&xas, 0);
This is problematic because get_unlocked_entry() will get the next present
entry in the range, and the next entry may not be locked. Therefore any
processing of the original locked entry will be skipped. This can cause
dax_layout_busy_page_range() to miss DMA-busy pages in the range, leading
file systems to free blocks whilst DMA operations are ongoing which can
lead to file system corruption.
Instead callers from within a xas_for_each() loop should be waiting for
the current entry to be unlocked without advancing the XArray state so a
new function is introduced to wait.
Also while we are here rename get_unlocked_entry() to
get_next_unlocked_entry() to make it clear that it may advance the
iterator state.
Link: https://lkml.kernel.org/r/b11b2baed7157dc900bf07a4571bf71b7cd82d97.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
dax_layout_busy_page_range() is used by file systems to scan the DAX
page-cache to unmap mapping pages from user-space and to determine if any
pages in the given range are busy, either due to ongoing DMA or other
get_user_pages() usage.
Currently it checks to see the file mapping is mapped into user-space with
mapping_mapped() and returns early if not, skipping the check for DMA busy
pages. This is wrong as pages may still be undergoing DMA access even if
they have subsequently been unmapped from user-space. Fix this by
dropping the check for mapping_mapped().
Link: https://lkml.kernel.org/r/d85ce6c2d1400ff111ed7302d9eef223d0243c57.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "fs/dax: Fix ZONE_DEVICE page reference counts", v9.
Device and FS DAX pages have always maintained their own page reference
counts without following the normal rules for page reference counting. In
particular pages are considered free when the refcount hits one rather
than zero and refcounts are not added when mapping the page.
Tracking this requires special PTE bits (PTE_DEVMAP) and a secondary
mechanism for allowing GUP to hold references on the page (see
get_dev_pagemap). However there doesn't seem to be any reason why FS DAX
pages need their own reference counting scheme.
By treating the refcounts on these pages the same way as normal pages we
can remove a lot of special checks. In particular pXd_trans_huge()
becomes the same as pXd_leaf(), although I haven't made that change here.
It also frees up a valuable SW define PTE bit on architectures that have
devmap PTE bits defined.
It also almost certainly allows further clean-up of the devmap managed
functions, but I have left that as a future improvment. It also enables
support for compound ZONE_DEVICE pages which is one of my primary
motivators for doing this work.
This patch (of 20):
FS DAX requires file systems to call into the DAX layout prior to
unlinking inodes to ensure there is no ongoing DMA or other remote access
to the direct mapped page. The fuse file system implements
fuse_dax_break_layouts() to do this which includes a comment indicating
that passing dmap_end == 0 leads to unmapping of the whole file.
However this is not true - passing dmap_end == 0 will not unmap anything
before dmap_start, and further more dax_layout_busy_page_range() will not
scan any of the range to see if there maybe ongoing DMA access to the
range. Fix this by passing -1 for dmap_end to fuse_dax_break_layouts()
which will invalidate the entire file range to
dax_layout_busy_page_range().
Link: https://lkml.kernel.org/r/cover.8068ad144a7eea4a813670301f4d2a86a8e68ec4.1740713401.git-series.apopple@nvidia.com
Link: https://lkml.kernel.org/r/f09a34b6c40032022e4ddee6fadb7cc676f08867.1740713401.git-series.apopple@nvidia.com
Fixes: 6ae330cad6ef ("virtiofs: serialize truncate/punch_hole and dax fault path")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Convert from pfn to folio instead of page and use those folios throughout
to avoid accesses to page->index and page->mapping.
Link: https://lkml.kernel.org/r/20241216155408.8102-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Cc: Dan Willaims <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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commit 79add3a3f795e ("ext4: notify when discard is not supported")
noted that keeping the DISCARD flag is for possibility that the underlying
device might change in future even without file system remount. However,
this scenario has rarely occurred in practice on the device side. Even if
it does occur, it can be resolved with remount. Clearing the DISCARD flag
not only prevents confusion caused by mount options but also avoids
sending unnecessary discard commands.
Signed-off-by: Diangang Li <lidiangang@bytedance.com>
Link: https://patch.msgid.link/20250311021310.669524-1-lidiangang@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Since the function jbd2_journal_unfile_buffer() is no longer called
anywhere after commit e5a120aeb57f ("jbd2: remove journal_head from
descriptor buffers"), so let's remove it.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250306063240.157884-1-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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capable() calls refer to enabled LSMs whether to permit or deny the
request. This is relevant in connection with SELinux, where a
capability check results in a policy decision and by default a denial
message on insufficient permission is issued.
It can lead to three undesired cases:
1. A denial message is generated, even in case the operation was an
unprivileged one and thus the syscall succeeded, creating noise.
2. To avoid the noise from 1. the policy writer adds a rule to ignore
those denial messages, hiding future syscalls, where the task
performs an actual privileged operation, leading to hidden limited
functionality of that task.
3. To avoid the noise from 1. the policy writer adds a rule to permit
the task the requested capability, while it does not need it,
violating the principle of least privilege.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250302160657.127253-2-cgoettsche@seltendoof.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Commit 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning") introduces
the sysfs control interface "mb_max_linear_groups" to address the problem
that rotational devices performance degrades when the "mb_optimize_scan"
feature is enabled, which may result in distant block group allocation.
However, the name of the interface was incorrect in the comment to the
ext4/mballoc.c file, and this patch fixes it, without further changes.
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250224012005.689549-1-wozizhi@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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In __jbd2_journal_erase(), the block_stop parameter includes the last
block of a contiguous region; however, the calculation of byte_stop is
incorrect, as it does not account for the bytes in that last block.
Consequently, the page cache is not cleared properly, which occasionally
causes the ext4/050 test to fail.
Since block_stop operates on inclusion semantics, it involves repeated
increments and decrements by 1, significantly increasing the complexity
of the calculations. Optimize the calculation and fix the incorrect
byte_stop by make both block_stop and byte_stop to use exclusion
semantics.
This fixes a failure in fstests ext4/050.
Fixes: 01d5d96542fd ("ext4: add discard/zeroout flags to journal flush")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250217065955.3829229-1-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Buffer heads are attached to folios, not to pages. Also
flush_dcache_page() is now deprecated in favour of flush_dcache_folio().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250213182303.2133205-1-willy@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Otherwise, if ext4_inode_attach_jinode() fails, a hung task will
happen because filemap_invalidate_unlock() isn't called to unlock
mapping->invalidate_lock. Like this:
EXT4-fs error (device sda) in ext4_setattr:5557: Out of memory
INFO: task fsstress:374 blocked for more than 122 seconds.
Not tainted 6.14.0-rc1-next-20250206-xfstests-dirty #726
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:fsstress state:D stack:0 pid:374 tgid:374 ppid:373
task_flags:0x440140 flags:0x00000000
Call Trace:
<TASK>
__schedule+0x2c9/0x7f0
schedule+0x27/0xa0
schedule_preempt_disabled+0x15/0x30
rwsem_down_read_slowpath+0x278/0x4c0
down_read+0x59/0xb0
page_cache_ra_unbounded+0x65/0x1b0
filemap_get_pages+0x124/0x3e0
filemap_read+0x114/0x3d0
vfs_read+0x297/0x360
ksys_read+0x6c/0xe0
do_syscall_64+0x4b/0x110
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fixes: c7fc0366c656 ("ext4: partial zero eof block on unaligned inode size extension")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Link: https://patch.msgid.link/20250213112247.3168709-1-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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There's issue as follows:
BUG: KASAN: use-after-free in ext4_xattr_inode_dec_ref_all+0x6ff/0x790
Read of size 4 at addr ffff88807b003000 by task syz-executor.0/15172
CPU: 3 PID: 15172 Comm: syz-executor.0
Call Trace:
__dump_stack lib/dump_stack.c:82 [inline]
dump_stack+0xbe/0xfd lib/dump_stack.c:123
print_address_description.constprop.0+0x1e/0x280 mm/kasan/report.c:400
__kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560
kasan_report+0x3a/0x50 mm/kasan/report.c:585
ext4_xattr_inode_dec_ref_all+0x6ff/0x790 fs/ext4/xattr.c:1137
ext4_xattr_delete_inode+0x4c7/0xda0 fs/ext4/xattr.c:2896
ext4_evict_inode+0xb3b/0x1670 fs/ext4/inode.c:323
evict+0x39f/0x880 fs/inode.c:622
iput_final fs/inode.c:1746 [inline]
iput fs/inode.c:1772 [inline]
iput+0x525/0x6c0 fs/inode.c:1758
ext4_orphan_cleanup fs/ext4/super.c:3298 [inline]
ext4_fill_super+0x8c57/0xba40 fs/ext4/super.c:5300
mount_bdev+0x355/0x410 fs/super.c:1446
legacy_get_tree+0xfe/0x220 fs/fs_context.c:611
vfs_get_tree+0x8d/0x2f0 fs/super.c:1576
do_new_mount fs/namespace.c:2983 [inline]
path_mount+0x119a/0x1ad0 fs/namespace.c:3316
do_mount+0xfc/0x110 fs/namespace.c:3329
__do_sys_mount fs/namespace.c:3540 [inline]
__se_sys_mount+0x219/0x2e0 fs/namespace.c:3514
do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x67/0xd1
Memory state around the buggy address:
ffff88807b002f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88807b002f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807b003000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88807b003080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88807b003100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
Above issue happens as ext4_xattr_delete_inode() isn't check xattr
is valid if xattr is in inode.
To solve above issue call xattr_check_inode() check if xattr if valid
in inode. In fact, we can directly verify in ext4_iget_extra_inode(),
so that there is no divergent verification.
Fixes: e50e5129f384 ("ext4: xattr-in-inode support")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250208063141.1539283-3-yebin@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Introduce ITAIL helper to get the bound of xattr in inode.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250208063141.1539283-2-yebin@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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During a checkpoint, the current active segment X may not be handled
properly. This occurs when segment X has 0 valid blocks and a non-zero
number of discard blocks, for the following reasons:
locate_dirty_segment() does not mark any active segment as a prefree
segment. As a result, segment X is not included in dirty_segmap[PRE], and
f2fs_clear_prefree_segments() skips it when handling prefree segments.
add_discard_addrs() skips any segment with 0 valid blocks, so segment X is
also skipped.
Consequently, no `struct discard_cmd` is actually created for segment X.
However, the ckpt_valid_map and cur_valid_map of segment X are synced by
seg_info_to_raw_sit() during the current checkpoint process. As a result,
it cannot find the missing discard bits even in subsequent checkpoints.
Consequently, the value of sbi->discard_blks remains non-zero. Thus, when
f2fs is umounted, CP_TRIMMED_FLAG will not be set due to the non-zero
sbi->discard_blks.
Relevant code process:
f2fs_write_checkpoint()
f2fs_flush_sit_entries()
list_for_each_entry_safe(ses, tmp, head, set_list) {
for_each_set_bit_from(segno, bitmap, end) {
...
add_discard_addrs(sbi, cpc, false); // skip segment X due to its 0 valid blocks
...
seg_info_to_raw_sit(); // sync ckpt_valid_map with cur_valid_map for segment X
...
}
}
f2fs_clear_prefree_segments(); // segment X is not included in dirty_segmap[PRE] and is skipped
This issue is easy to reproduce with the following operations:
root # mkfs.f2fs -f /dev/f2fs_dev
root # mount -t f2fs /dev/f2fs_dev /mnt_point
root # dd if=/dev/blk_dev of=/mnt_point/1.bin bs=4k count=256
root # sync
root # rm /mnt_point/1.bin
root # umount /mnt_point
root # dump.f2fs /dev/f2fs_dev | grep "checkpoint state"
Info: checkpoint state = 45 : crc compacted_summary unmount ---- 'trimmed' flag is missing
Since add_discard_addrs() can handle active segments with non-zero valid
blocks, it is reasonable to fix this issue by allowing it to also handle
active segments with 0 valid blocks.
Fixes: b29555505d81 ("f2fs: add key functions for small discards")
Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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this is unnecessary when we know we are overwriting already allocated
blocks and the overhead of starting a transaction can be significant
especially for multithreaded workloads doing small writes.
Signed-off-by: Yohan Joung <yohan.joung@sk.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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If @server->tcpStatus is set to CifsNeedReconnect after acquiring
@ses->session_mutex in smb2_reconnect() or cifs_reconnect_tcon(), it
means that a concurrent thread failed to negotiate, in which case the
server is no longer responding to any SMB requests, so there is no
point making the caller retry the IO by returning -EAGAIN.
Fix this by returning -EHOSTDOWN to the callers on soft mounts.
Cc: David Howells <dhowells@redhat.com>
Reported-by: Jay Shin <jaeshin@redhat.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Add a trace_nfs4_offload_status trace point that looks just like
trace_nfs4_offload_cancel. Promote that event to an event class to
avoid duplicating code.
An alternative approach would be to expand trace_nfs4_offload_status
to report more of the actual OFFLOAD_STATUS result.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Link: https://lore.kernel.org/r/20250113153235.48706-16-cel@kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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We've found that there are cases where a transport disconnection
results in the loss of callback RPCs. NFS servers typically do not
retransmit callback operations after a disconnect.
This can be a problem for the Linux NFS client's current
implementation of asynchronous COPY, which waits indefinitely for a
CB_OFFLOAD callback. If a transport disconnect occurs while an async
COPY is running, there's a good chance the client will never get the
completing CB_OFFLOAD.
Fix this by implementing the OFFLOAD_STATUS operation so that the
Linux NFS client can probe the NFS server if it doesn't see a
CB_OFFLOAD in a reasonable amount of time.
This patch implements a simplistic check. As future work, the client
might also be able to detect whether there is no forward progress on
the request asynchronous COPY operation, and CANCEL it.
Suggested-by: Olga Kornievskaia <kolga@netapp.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218735
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Link: https://lore.kernel.org/r/20250113153235.48706-15-cel@kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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Enable the Linux NFS client to observe the progress of an offloaded
asynchronous COPY operation. This new operation will be put to use
in a subsequent patch.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Link: https://lore.kernel.org/r/20250113153235.48706-14-cel@kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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