When netfslib writes to a folio that it doesn't have data for, but that
data exists on the server, it will make a 'streaming write' whereby it
stores data in a folio that is marked dirty, but not uptodate. When it
does this, it attaches a record to folio->private to track the dirty
region.
When truncate() or fallocate() wants to invalidate part of such a folio, it
will call into ->invalidate_folio(), specifying the part of the folio that
is to be invalidated. netfs_invalidate_folio(), on behalf of the
filesystem, must then determine how to trim the streaming write record. In
a couple of cases, however, it does this incorrectly (the reduce-length and
move-start cases are switched over and don't, in any case, calculate the
value correctly).
Fix this by making the logic tree more obvious and fixing the cases.
Fixes: 9ebff83e64 ("netfs: Prep to use folio->private for write grouping and streaming write")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20240823200819.532106-5-dhowells@redhat.com
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Pankaj Raghav <p.raghav@samsung.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Fix netfs_release_folio() to say no (ie. return false) if the folio is
dirty (analogous with iomap's behaviour). Without this, it will say yes to
the release of a dirty page by split_huge_page_to_list_to_order(), which
will result in the loss of untruncated data in the folio.
Without this, the generic/075 and generic/112 xfstests (both fsx-based
tests) fail with minimum folio size patches applied[1].
Fixes: c1ec4d7c2e ("netfs: Provide invalidate_folio and release_folio calls")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20240815090849.972355-1-kernel@pankajraghav.com/ [1]
Link: https://lore.kernel.org/r/20240823200819.532106-4-dhowells@redhat.com
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Pankaj Raghav <p.raghav@samsung.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
If a program is watching a file on a 9p mount, it won't see any change in
size if the file being exported by the server is changed directly in the
source filesystem, presumably because 9p doesn't have change notifications,
and because netfs skips the reads if the file is empty.
Fix this by attempting to read the full size specified when a DIO read is
requested (such as when 9p is operating in unbuffered mode) and dealing
with a short read if the EOF was less than the expected read.
To make this work, filesystems using netfslib must not set
NETFS_SREQ_CLEAR_TAIL if performing a DIO read where that read hit the EOF.
I don't want to mandatorily clear this flag in netfslib for DIO because,
say, ceph might make a read from an object that is not completely filled,
but does not reside at the end of file - and so we need to clear the
excess.
This can be tested by watching an empty file over 9p within a VM (such as
in the ktest framework):
while true; do read content; if [ -n "$content" ]; then echo $content; break; fi; done < /host/tmp/foo
then writing something into the empty file. The watcher should immediately
display the file content and break out of the loop. Without this fix, it
remains in the loop indefinitely.
Fixes: 80105ed2fd ("9p: Use netfslib read/write_iter")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218916
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/1229195.1723211769@warthog.procyon.org.uk
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The NETFS_RREQ_USE_PGPRIV2 and NETFS_RREQ_WRITE_TO_CACHE flags aren't used
correctly. The problem is that we try to set them up in the request
initialisation, but we the cache may be in the process of setting up still,
and so the state may not be correct. Further, we secondarily sample the
cache state and make contradictory decisions later.
The issue arises because we set up the cache resources, which allows the
cache's ->prepare_read() to switch on NETFS_SREQ_COPY_TO_CACHE - which
triggers cache writing even if we didn't set the flags when allocating.
Fix this in the following way:
(1) Drop NETFS_ICTX_USE_PGPRIV2 and instead set NETFS_RREQ_USE_PGPRIV2 in
->init_request() rather than trying to juggle that in
netfs_alloc_request().
(2) Repurpose NETFS_RREQ_USE_PGPRIV2 to merely indicate that if caching is
to be done, then PG_private_2 is to be used rather than only setting
it if we decide to cache and then having netfs_rreq_unlock_folios()
set the non-PG_private_2 writeback-to-cache if it wasn't set.
(3) Split netfs_rreq_unlock_folios() into two functions, one of which
contains the deprecated code for using PG_private_2 to avoid
accidentally doing the writeback path - and always use it if
USE_PGPRIV2 is set.
(4) As NETFS_ICTX_USE_PGPRIV2 is removed, make netfs_write_begin() always
wait for PG_private_2. This function is deprecated and only used by
ceph anyway, and so label it so.
(5) Drop the NETFS_RREQ_WRITE_TO_CACHE flag and use
fscache_operation_valid() on the cache_resources instead. This has
the advantage of picking up the result of netfs_begin_cache_read() and
fscache_begin_write_operation() - which are called after the object is
initialised and will wait for the cache to come to a usable state.
Just reverting ae678317b95e[1] isn't a sufficient fix, so this need to be
applied on top of that. Without this as well, things like:
rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: {
and:
WARNING: CPU: 13 PID: 3621 at fs/ceph/caps.c:3386
may happen, along with some UAFs due to PG_private_2 not getting used to
wait on writeback completion.
Fixes: 2ff1e97587 ("netfs: Replace PG_fscache by setting folio->private and marking dirty")
Reported-by: Max Kellermann <max.kellermann@ionos.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Xiubo Li <xiubli@redhat.com>
cc: Hristo Venev <hristo@venev.name>
cc: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: ceph-devel@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/3575457.1722355300@warthog.procyon.org.uk/ [1]
Link: https://lore.kernel.org/r/1173209.1723152682@warthog.procyon.org.uk
Signed-off-by: Christian Brauner <brauner@kernel.org>
This reverts commit ae678317b9.
Revert the patch that removes the deprecated use of PG_private_2 in
netfslib for the moment as Ceph is actually still using this to track
data copied to the cache.
Fixes: ae678317b9 ("netfs: Remove deprecated use of PG_private_2 as a second writeback flag")
Reported-by: Max Kellermann <max.kellermann@ionos.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Xiubo Li <xiubli@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: ceph-devel@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
https: //lore.kernel.org/r/3575457.1722355300@warthog.procyon.org.uk
Signed-off-by: Christian Brauner <brauner@kernel.org>
Commit 6b8e61472529 ("netfs: Rename CONFIG_FSCACHE_DEBUG to
CONFIG_NETFS_DEBUG") renames the config, but introduces two issues: First,
NETFS_DEBUG mistakenly depends on the non-existing config NETFS, whereas
the actual intended config is called NETFS_SUPPORT. Second, the config
renaming misses to adjust the documentation of the functionality of this
config.
Clean up those two points.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Link: https://lore.kernel.org/r/20240731073902.69262-1-lukas.bulwahn@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
This fixes a NULL pointer dereference bug due to a data race which
looks like this:
BUG: kernel NULL pointer dereference, address: 0000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 33 PID: 16573 Comm: kworker/u97:799 Not tainted 6.8.7-cm4all1-hp+ #43
Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 10/17/2018
Workqueue: events_unbound netfs_rreq_write_to_cache_work
RIP: 0010:cachefiles_prepare_write+0x30/0xa0
Code: 57 41 56 45 89 ce 41 55 49 89 cd 41 54 49 89 d4 55 53 48 89 fb 48 83 ec 08 48 8b 47 08 48 83 7f 10 00 48 89 34 24 48 8b 68 20 <48> 8b 45 08 4c 8b 38 74 45 49 8b 7f 50 e8 4e a9 b0 ff 48 8b 73 10
RSP: 0018:ffffb4e78113bde0 EFLAGS: 00010286
RAX: ffff976126be6d10 RBX: ffff97615cdb8438 RCX: 0000000000020000
RDX: ffff97605e6c4c68 RSI: ffff97605e6c4c60 RDI: ffff97615cdb8438
RBP: 0000000000000000 R08: 0000000000278333 R09: 0000000000000001
R10: ffff97605e6c4600 R11: 0000000000000001 R12: ffff97605e6c4c68
R13: 0000000000020000 R14: 0000000000000001 R15: ffff976064fe2c00
FS: 0000000000000000(0000) GS:ffff9776dfd40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 000000005942c002 CR4: 00000000001706f0
Call Trace:
<TASK>
? __die+0x1f/0x70
? page_fault_oops+0x15d/0x440
? search_module_extables+0xe/0x40
? fixup_exception+0x22/0x2f0
? exc_page_fault+0x5f/0x100
? asm_exc_page_fault+0x22/0x30
? cachefiles_prepare_write+0x30/0xa0
netfs_rreq_write_to_cache_work+0x135/0x2e0
process_one_work+0x137/0x2c0
worker_thread+0x2e9/0x400
? __pfx_worker_thread+0x10/0x10
kthread+0xcc/0x100
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>
Modules linked in:
CR2: 0000000000000008
---[ end trace 0000000000000000 ]---
This happened because fscache_cookie_state_machine() was slow and was
still running while another process invoked fscache_unuse_cookie();
this led to a fscache_cookie_lru_do_one() call, setting the
FSCACHE_COOKIE_DO_LRU_DISCARD flag, which was picked up by
fscache_cookie_state_machine(), withdrawing the cookie via
cachefiles_withdraw_cookie(), clearing cookie->cache_priv.
At the same time, yet another process invoked
cachefiles_prepare_write(), which found a NULL pointer in this code
line:
struct cachefiles_object *object = cachefiles_cres_object(cres);
The next line crashes, obviously:
struct cachefiles_cache *cache = object->volume->cache;
During cachefiles_prepare_write(), the "n_accesses" counter is
non-zero (via fscache_begin_operation()). The cookie must not be
withdrawn until it drops to zero.
The counter is checked by fscache_cookie_state_machine() before
switching to FSCACHE_COOKIE_STATE_RELINQUISHING and
FSCACHE_COOKIE_STATE_WITHDRAWING (in "case
FSCACHE_COOKIE_STATE_FAILED"), but not for
FSCACHE_COOKIE_STATE_LRU_DISCARDING ("case
FSCACHE_COOKIE_STATE_ACTIVE").
This patch adds the missing check. With a non-zero access counter,
the function returns and the next fscache_end_cookie_access() call
will queue another fscache_cookie_state_machine() call to handle the
still-pending FSCACHE_COOKIE_DO_LRU_DISCARD.
Fixes: 12bb21a29c ("fscache: Implement cookie user counting and resource pinning")
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20240729162002.3436763-2-dhowells@redhat.com
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
As in commit 4e527d5841 ("iomap: fault in smaller chunks for non-large
folio mappings"), we can see a performance loss for filesystems
which have not yet been converted to large folios.
Fixes: c38f4e96e6 ("netfs: Provide func to copy data to pagecache for buffered write")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240527201735.1898381-1-willy@infradead.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
When netfslib is performing writeback (ie. ->writepages), it maintains two
parallel streams of writes, one to the server and one to the cache, but it
doesn't mark either stream of writes as active until it gets some data that
needs to be written to that stream.
This is done because some folios will only be written to the cache
(e.g. copying to the cache on read is done by marking the folios and
letting writeback do the actual work) and sometimes we'll only be writing
to the server (e.g. if there's no cache).
Now, since we don't actually dispatch uploads and cache writes in parallel,
but rather flip between the streams, depending on which has the lowest
so-far-issued offset, and don't wait for the subreqs to finish before
flipping, we can end up in a situation where, say, we issue a write to the
server and this completes before we start the write to the cache.
But because we only activate a stream when we first add a subreq to it, the
result collection code may run before we manage to activate the stream -
resulting in the folio being cleaned and having the writeback-in-progress
mark removed. At this point, the folio no longer belongs to us.
This is only really a problem for folios that need to be written to both
streams - and in that case, the upload to the server is started first,
followed by the write to the cache - and the cache write may see a bad
folio.
Fix this by activating the cache stream up front if there's a cache
available. If there's a cache, then all data is going to be written to it.
Fixes: 288ace2f57 ("netfs: New writeback implementation")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/1599053.1721398818@warthog.procyon.org.uk
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
walkers") is known to cause a performance regression
(https://lore.kernel.org/all/3acefad9-96e5-4681-8014-827d6be71c7a@linux.ibm.com/T/#mfa809800a7862fb5bdf834c6f71a3a5113eb83ff).
Yu has a fix which I'll send along later via the hotfixes branch.
- In the series "mm: Avoid possible overflows in dirty throttling" Jan
Kara addresses a couple of issues in the writeback throttling code.
These fixes are also targetted at -stable kernels.
- Ryusuke Konishi's series "nilfs2: fix potential issues related to
reserved inodes" does that. This should actually be in the
mm-nonmm-stable tree, along with the many other nilfs2 patches. My bad.
- More folio conversions from Kefeng Wang in the series "mm: convert to
folio_alloc_mpol()"
- Kemeng Shi has sent some cleanups to the writeback code in the series
"Add helper functions to remove repeated code and improve readability of
cgroup writeback"
- Kairui Song has made the swap code a little smaller and a little
faster in the series "mm/swap: clean up and optimize swap cache index".
- In the series "mm/memory: cleanly support zeropage in
vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
Hildenbrand has reworked the rather sketchy handling of the use of the
zeropage in MAP_SHARED mappings. I don't see any runtime effects here -
more a cleanup/understandability/maintainablity thing.
- Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling of
higher addresses, for aarch64. The (poorly named) series is
"Restructure va_high_addr_switch".
- The core TLB handling code gets some cleanups and possible slight
optimizations in Bang Li's series "Add update_mmu_tlb_range() to
simplify code".
- Jane Chu has improved the handling of our
fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in the
series "Enhance soft hwpoison handling and injection".
- Jeff Johnson has sent a billion patches everywhere to add
MODULE_DESCRIPTION() to everything. Some landed in this pull.
- In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang has
simplified migration's use of hardware-offload memory copying.
- Yosry Ahmed performs more folio API conversions in his series "mm:
zswap: trivial folio conversions".
- In the series "large folios swap-in: handle refault cases first",
Chuanhua Han inches us forward in the handling of large pages in the
swap code. This is a cleanup and optimization, working toward the end
objective of full support of large folio swapin/out.
- In the series "mm,swap: cleanup VMA based swap readahead window
calculation", Huang Ying has contributed some cleanups and a possible
fixlet to his VMA based swap readahead code.
- In the series "add mTHP support for anonymous shmem" Baolin Wang has
taught anonymous shmem mappings to use multisize THP. By default this
is a no-op - users must opt in vis sysfs controls. Dramatic
improvements in pagefault latency are realized.
- David Hildenbrand has some cleanups to our remaining use of
page_mapcount() in the series "fs/proc: move page_mapcount() to
fs/proc/internal.h".
- David also has some highmem accounting cleanups in the series
"mm/highmem: don't track highmem pages manually".
- Build-time fixes and cleanups from John Hubbard in the series
"cleanups, fixes, and progress towards avoiding "make headers"".
- Cleanups and consolidation of the core pagemap handling from Barry
Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
and utilize them".
- Lance Yang's series "Reclaim lazyfree THP without splitting" has
reduced the latency of the reclaim of pmd-mapped THPs under fairly
common circumstances. A 10x speedup is seen in a microbenchmark.
It does this by punting to aother CPU but I guess that's a win unless
all CPUs are pegged.
- hugetlb_cgroup cleanups from Xiu Jianfeng in the series
"mm/hugetlb_cgroup: rework on cftypes".
- Miaohe Lin's series "Some cleanups for memory-failure" does just that
thing.
- Is anyone reading this stuff? If so, email me!
- Someone other than SeongJae has developed a DAMON feature in Honggyu
Kim's series "DAMON based tiered memory management for CXL memory".
This adds DAMON features which may be used to help determine the
efficiency of our placement of CXL/PCIe attached DRAM.
- DAMON user API centralization and simplificatio work in SeongJae
Park's series "mm/damon: introduce DAMON parameters online commit
function".
- In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
David Hildenbrand does some maintenance work on zsmalloc - partially
modernizing its use of pageframe fields.
- Kefeng Wang provides more folio conversions in the series "mm: remove
page_maybe_dma_pinned() and page_mkclean()".
- More cleanup from David Hildenbrand, this time in the series
"mm/memory_hotplug: use PageOffline() instead of PageReserved() for
!ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline()
pages" and permits the removal of some virtio-mem hacks.
- Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
__folio_add_anon_rmap()" is a cleanup to the anon folio handling in
preparation for mTHP (multisize THP) swapin.
- Kefeng Wang's series "mm: improve clear and copy user folio"
implements more folio conversions, this time in the area of large folio
userspace copying.
- The series "Docs/mm/damon/maintaier-profile: document a mailing tool
and community meetup series" tells people how to get better involved
with other DAMON developers. From SeongJae Park.
- A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
that.
- David Hildenbrand sends along more cleanups, this time against the
migration code. The series is "mm/migrate: move NUMA hinting fault
folio isolation + checks under PTL".
- Jan Kara has found quite a lot of strangenesses and minor errors in
the readahead code. He addresses this in the series "mm: Fix various
readahead quirks".
- SeongJae Park's series "selftests/damon: test DAMOS tried regions and
{min,max}_nr_regions" adds features and addresses errors in DAMON's self
testing code.
- Gavin Shan has found a userspace-triggerable WARN in the pagecache
code. The series "mm/filemap: Limit page cache size to that supported
by xarray" addresses this. The series is marked cc:stable.
- Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
and cleanup" cleans up and slightly optimizes KSM.
- Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
code motion. The series (which also makes the memcg-v1 code
Kconfigurable) are
"mm: memcg: separate legacy cgroup v1 code and put under config
option" and
"mm: memcg: put cgroup v1-specific memcg data under CONFIG_MEMCG_V1"
- Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
adds an additional feature to this cgroup-v2 control file.
- The series "Userspace controls soft-offline pages" from Jiaqi Yan
permits userspace to stop the kernel's automatic treatment of excessive
correctable memory errors. In order to permit userspace to monitor and
handle this situation.
- Kefeng Wang's series "mm: migrate: support poison recover from migrate
folio" teaches the kernel to appropriately handle migration from
poisoned source folios rather than simply panicing.
- SeongJae Park's series "Docs/damon: minor fixups and improvements"
does those things.
- In the series "mm/zsmalloc: change back to per-size_class lock"
Chengming Zhou improves zsmalloc's scalability and memory utilization.
- Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
pinning memfd folios" makes the GUP code use FOLL_PIN rather than bare
refcount increments. So these paes can first be moved aside if they
reside in the movable zone or a CMA block.
- Andrii Nakryiko has added a binary ioctl()-based API to /proc/pid/maps
for much faster reading of vma information. The series is "query VMAs
from /proc/<pid>/maps".
- In the series "mm: introduce per-order mTHP split counters" Lance Yang
improves the kernel's presentation of developer information related to
multisize THP splitting.
- Michael Ellerman has developed the series "Reimplement huge pages
without hugepd on powerpc (8xx, e500, book3s/64)". This permits
userspace to use all available huge page sizes.
- In the series "revert unconditional slab and page allocator fault
injection calls" Vlastimil Babka removes a performance-affecting and not
very useful feature from slab fault injection.
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Merge tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- In the series "mm: Avoid possible overflows in dirty throttling" Jan
Kara addresses a couple of issues in the writeback throttling code.
These fixes are also targetted at -stable kernels.
- Ryusuke Konishi's series "nilfs2: fix potential issues related to
reserved inodes" does that. This should actually be in the
mm-nonmm-stable tree, along with the many other nilfs2 patches. My
bad.
- More folio conversions from Kefeng Wang in the series "mm: convert to
folio_alloc_mpol()"
- Kemeng Shi has sent some cleanups to the writeback code in the series
"Add helper functions to remove repeated code and improve readability
of cgroup writeback"
- Kairui Song has made the swap code a little smaller and a little
faster in the series "mm/swap: clean up and optimize swap cache
index".
- In the series "mm/memory: cleanly support zeropage in
vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
Hildenbrand has reworked the rather sketchy handling of the use of
the zeropage in MAP_SHARED mappings. I don't see any runtime effects
here - more a cleanup/understandability/maintainablity thing.
- Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling
of higher addresses, for aarch64. The (poorly named) series is
"Restructure va_high_addr_switch".
- The core TLB handling code gets some cleanups and possible slight
optimizations in Bang Li's series "Add update_mmu_tlb_range() to
simplify code".
- Jane Chu has improved the handling of our
fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in
the series "Enhance soft hwpoison handling and injection".
- Jeff Johnson has sent a billion patches everywhere to add
MODULE_DESCRIPTION() to everything. Some landed in this pull.
- In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang
has simplified migration's use of hardware-offload memory copying.
- Yosry Ahmed performs more folio API conversions in his series "mm:
zswap: trivial folio conversions".
- In the series "large folios swap-in: handle refault cases first",
Chuanhua Han inches us forward in the handling of large pages in the
swap code. This is a cleanup and optimization, working toward the end
objective of full support of large folio swapin/out.
- In the series "mm,swap: cleanup VMA based swap readahead window
calculation", Huang Ying has contributed some cleanups and a possible
fixlet to his VMA based swap readahead code.
- In the series "add mTHP support for anonymous shmem" Baolin Wang has
taught anonymous shmem mappings to use multisize THP. By default this
is a no-op - users must opt in vis sysfs controls. Dramatic
improvements in pagefault latency are realized.
- David Hildenbrand has some cleanups to our remaining use of
page_mapcount() in the series "fs/proc: move page_mapcount() to
fs/proc/internal.h".
- David also has some highmem accounting cleanups in the series
"mm/highmem: don't track highmem pages manually".
- Build-time fixes and cleanups from John Hubbard in the series
"cleanups, fixes, and progress towards avoiding "make headers"".
- Cleanups and consolidation of the core pagemap handling from Barry
Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
and utilize them".
- Lance Yang's series "Reclaim lazyfree THP without splitting" has
reduced the latency of the reclaim of pmd-mapped THPs under fairly
common circumstances. A 10x speedup is seen in a microbenchmark.
It does this by punting to aother CPU but I guess that's a win unless
all CPUs are pegged.
- hugetlb_cgroup cleanups from Xiu Jianfeng in the series
"mm/hugetlb_cgroup: rework on cftypes".
- Miaohe Lin's series "Some cleanups for memory-failure" does just that
thing.
- Someone other than SeongJae has developed a DAMON feature in Honggyu
Kim's series "DAMON based tiered memory management for CXL memory".
This adds DAMON features which may be used to help determine the
efficiency of our placement of CXL/PCIe attached DRAM.
- DAMON user API centralization and simplificatio work in SeongJae
Park's series "mm/damon: introduce DAMON parameters online commit
function".
- In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
David Hildenbrand does some maintenance work on zsmalloc - partially
modernizing its use of pageframe fields.
- Kefeng Wang provides more folio conversions in the series "mm: remove
page_maybe_dma_pinned() and page_mkclean()".
- More cleanup from David Hildenbrand, this time in the series
"mm/memory_hotplug: use PageOffline() instead of PageReserved() for
!ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline()
pages" and permits the removal of some virtio-mem hacks.
- Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
__folio_add_anon_rmap()" is a cleanup to the anon folio handling in
preparation for mTHP (multisize THP) swapin.
- Kefeng Wang's series "mm: improve clear and copy user folio"
implements more folio conversions, this time in the area of large
folio userspace copying.
- The series "Docs/mm/damon/maintaier-profile: document a mailing tool
and community meetup series" tells people how to get better involved
with other DAMON developers. From SeongJae Park.
- A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
that.
- David Hildenbrand sends along more cleanups, this time against the
migration code. The series is "mm/migrate: move NUMA hinting fault
folio isolation + checks under PTL".
- Jan Kara has found quite a lot of strangenesses and minor errors in
the readahead code. He addresses this in the series "mm: Fix various
readahead quirks".
- SeongJae Park's series "selftests/damon: test DAMOS tried regions and
{min,max}_nr_regions" adds features and addresses errors in DAMON's
self testing code.
- Gavin Shan has found a userspace-triggerable WARN in the pagecache
code. The series "mm/filemap: Limit page cache size to that supported
by xarray" addresses this. The series is marked cc:stable.
- Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
and cleanup" cleans up and slightly optimizes KSM.
- Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
code motion. The series (which also makes the memcg-v1 code
Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put
under config option" and "mm: memcg: put cgroup v1-specific memcg
data under CONFIG_MEMCG_V1"
- Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
adds an additional feature to this cgroup-v2 control file.
- The series "Userspace controls soft-offline pages" from Jiaqi Yan
permits userspace to stop the kernel's automatic treatment of
excessive correctable memory errors. In order to permit userspace to
monitor and handle this situation.
- Kefeng Wang's series "mm: migrate: support poison recover from
migrate folio" teaches the kernel to appropriately handle migration
from poisoned source folios rather than simply panicing.
- SeongJae Park's series "Docs/damon: minor fixups and improvements"
does those things.
- In the series "mm/zsmalloc: change back to per-size_class lock"
Chengming Zhou improves zsmalloc's scalability and memory
utilization.
- Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
pinning memfd folios" makes the GUP code use FOLL_PIN rather than
bare refcount increments. So these paes can first be moved aside if
they reside in the movable zone or a CMA block.
- Andrii Nakryiko has added a binary ioctl()-based API to
/proc/pid/maps for much faster reading of vma information. The series
is "query VMAs from /proc/<pid>/maps".
- In the series "mm: introduce per-order mTHP split counters" Lance
Yang improves the kernel's presentation of developer information
related to multisize THP splitting.
- Michael Ellerman has developed the series "Reimplement huge pages
without hugepd on powerpc (8xx, e500, book3s/64)". This permits
userspace to use all available huge page sizes.
- In the series "revert unconditional slab and page allocator fault
injection calls" Vlastimil Babka removes a performance-affecting and
not very useful feature from slab fault injection.
* tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits)
mm/mglru: fix ineffective protection calculation
mm/zswap: fix a white space issue
mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio
mm/hugetlb: fix possible recursive locking detected warning
mm/gup: clear the LRU flag of a page before adding to LRU batch
mm/numa_balancing: teach mpol_to_str about the balancing mode
mm: memcg1: convert charge move flags to unsigned long long
alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting
lib: reuse page_ext_data() to obtain codetag_ref
lib: add missing newline character in the warning message
mm/mglru: fix overshooting shrinker memory
mm/mglru: fix div-by-zero in vmpressure_calc_level()
mm/kmemleak: replace strncpy() with strscpy()
mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC
mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB
mm: ignore data-race in __swap_writepage
hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr
mm: shmem: rename mTHP shmem counters
mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async()
mm/migrate: putback split folios when numa hint migration fails
...
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Merge tag 'vfs-6.10-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
"cachefiles:
- Export an existing and add a new cachefile helper to be used in
filesystems to fix reference count bugs
- Use the newly added fscache_ty_get_volume() helper to get a
reference count on an fscache_volume to handle volumes that are
about to be removed cleanly
- After withdrawing a fscache_cache via FSCACHE_CACHE_IS_WITHDRAWN
wait for all ongoing cookie lookups to complete and for the object
count to reach zero
- Propagate errors from vfs_getxattr() to avoid an infinite loop in
cachefiles_check_volume_xattr() because it keeps seeing ESTALE
- Don't send new requests when an object is dropped by raising
CACHEFILES_ONDEMAND_OJBSTATE_DROPPING
- Cancel all requests for an object that is about to be dropped
- Wait for the ondemand_boject_worker to finish before dropping a
cachefiles object to prevent use-after-free
- Use cyclic allocation for message ids to better handle id recycling
- Add missing lock protection when iterating through the xarray when
polling
netfs:
- Use standard logging helpers for debug logging
VFS:
- Fix potential use-after-free in file locks during
trace_posix_lock_inode(). The tracepoint could fire while another
task raced it and freed the lock that was requested to be traced
- Only increment the nr_dentry_negative counter for dentries that are
present on the superblock LRU. Currently, DCACHE_LRU_LIST list is
used to detect this case. However, the flag is also raised in
combination with DCACHE_SHRINK_LIST to indicate that dentry->d_lru
is used. So checking only DCACHE_LRU_LIST will lead to wrong
nr_dentry_negative count. Fix the check to not count dentries that
are on a shrink related list
Misc:
- hfsplus: fix an uninitialized value issue in copy_name
- minix: fix minixfs_rename with HIGHMEM. It still uses kunmap() even
though we switched it to kmap_local_page() a while ago"
* tag 'vfs-6.10-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
minixfs: Fix minixfs_rename with HIGHMEM
hfsplus: fix uninit-value in copy_name
vfs: don't mod negative dentry count when on shrinker list
filelock: fix potential use-after-free in posix_lock_inode
cachefiles: add missing lock protection when polling
cachefiles: cyclic allocation of msg_id to avoid reuse
cachefiles: wait for ondemand_object_worker to finish when dropping object
cachefiles: cancel all requests for the object that is being dropped
cachefiles: stop sending new request when dropping object
cachefiles: propagate errors from vfs_getxattr() to avoid infinite loop
cachefiles: fix slab-use-after-free in cachefiles_withdraw_cookie()
cachefiles: fix slab-use-after-free in fscache_withdraw_volume()
netfs, fscache: export fscache_put_volume() and add fscache_try_get_volume()
netfs: Switch debug logging to pr_debug()
libaokun@huaweicloud.com <libaokun@huaweicloud.com> says:
This is the third version of this patch series, in which another patch set
is subsumed into this one to avoid confusing the two patch sets.
(https://patchwork.kernel.org/project/linux-fsdevel/list/?series=854914)
We've been testing ondemand mode for cachefiles since January, and we're
almost done. We hit a lot of issues during the testing period, and this
patch series fixes some of the issues. The patches have passed internal
testing without regression.
The following is a brief overview of the patches, see the patches for
more details.
Patch 1-2: Add fscache_try_get_volume() helper function to avoid
fscache_volume use-after-free on cache withdrawal.
Patch 3: Fix cachefiles_lookup_cookie() and cachefiles_withdraw_cache()
concurrency causing cachefiles_volume use-after-free.
Patch 4: Propagate error codes returned by vfs_getxattr() to avoid
endless loops.
Patch 5-7: A read request waiting for reopen could be closed maliciously
before the reopen worker is executing or waiting to be scheduled. So
ondemand_object_worker() may be called after the info and object and even
the cache have been freed and trigger use-after-free. So use
cancel_work_sync() in cachefiles_ondemand_clean_object() to cancel the
reopen worker or wait for it to finish. Since it makes no sense to wait
for the daemon to complete the reopen request, to avoid this pointless
operation blocking cancel_work_sync(), Patch 1 avoids request generation
by the DROPPING state when the request has not been sent, and Patch 2
flushes the requests of the current object before cancel_work_sync().
Patch 8: Cyclic allocation of msg_id to avoid msg_id reuse misleading
the daemon to cause hung.
Patch 9: Hold xas_lock during polling to avoid dereferencing reqs causing
use-after-free. This issue was triggered frequently in our tests, and we
found that anolis 5.10 had fixed it. So to avoid failing the test, this
patch is pushed upstream as well.
Baokun Li (7):
netfs, fscache: export fscache_put_volume() and add
fscache_try_get_volume()
cachefiles: fix slab-use-after-free in fscache_withdraw_volume()
cachefiles: fix slab-use-after-free in cachefiles_withdraw_cookie()
cachefiles: propagate errors from vfs_getxattr() to avoid infinite
loop
cachefiles: stop sending new request when dropping object
cachefiles: cancel all requests for the object that is being dropped
cachefiles: cyclic allocation of msg_id to avoid reuse
Hou Tao (1):
cachefiles: wait for ondemand_object_worker to finish when dropping
object
Jingbo Xu (1):
cachefiles: add missing lock protection when polling
fs/cachefiles/cache.c | 45 ++++++++++++++++++++++++++++-
fs/cachefiles/daemon.c | 4 +--
fs/cachefiles/internal.h | 3 ++
fs/cachefiles/ondemand.c | 52 ++++++++++++++++++++++++++++++----
fs/cachefiles/volume.c | 1 -
fs/cachefiles/xattr.c | 5 +++-
fs/netfs/fscache_volume.c | 14 +++++++++
fs/netfs/internal.h | 2 --
include/linux/fscache-cache.h | 6 ++++
include/trace/events/fscache.h | 4 +++
10 files changed, 123 insertions(+), 13 deletions(-)
Link: https://lore.kernel.org/r/20240628062930.2467993-1-libaokun@huaweicloud.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
folio_file_pos is only needed for mixed usage of page cache and swap
cache, for pure page cache usage, the caller can just use folio_pos
instead.
It can't be a swap cache page here. Swap mapping may only call into fs
through swap_rw and that is not supported for netfs. So just drop it and
use folio_pos instead.
Link: https://lkml.kernel.org/r/20240521175854.96038-7-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Export fscache_put_volume() and add fscache_try_get_volume()
helper function to allow cachefiles to get/put fscache_volume
via linux/fscache-cache.h.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240628062930.2467993-2-libaokun@huaweicloud.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Fix netfs_page_mkwrite() to check that folio->mapping is valid once it has
taken the folio lock (as filemap_page_mkwrite() does). Without this,
generic/247 occasionally oopses with something like the following:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
RIP: 0010:trace_event_raw_event_netfs_folio+0x61/0xc0
...
Call Trace:
<TASK>
? __die_body+0x1a/0x60
? page_fault_oops+0x6e/0xa0
? exc_page_fault+0xc2/0xe0
? asm_exc_page_fault+0x22/0x30
? trace_event_raw_event_netfs_folio+0x61/0xc0
trace_netfs_folio+0x39/0x40
netfs_page_mkwrite+0x14c/0x1d0
do_page_mkwrite+0x50/0x90
do_pte_missing+0x184/0x200
__handle_mm_fault+0x42d/0x500
handle_mm_fault+0x121/0x1f0
do_user_addr_fault+0x23e/0x3c0
exc_page_fault+0xc2/0xe0
asm_exc_page_fault+0x22/0x30
This is due to the invalidate_inode_pages2_range() issued at the end of the
DIO write interfering with the mmap'd writes.
Fixes: 102a7e2c59 ("netfs: Allow buffered shared-writeable mmap through netfs_page_mkwrite()")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/780211.1719318546@warthog.procyon.org.uk
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Delete some xarray-based buffer wangling functions that are intended for
use with bounce buffering, but aren't used because bounce-buffering got
deferred to a later patch series. Now, however, the intention is to use
something other than an xarray to do this.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20240620173137.610345-9-dhowells@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
During the writeback procedure, at the end of netfs_write_folio(), pending
write operations are flushed if the amount of write-streaming data stored
in a page is less than the size of the folio because if we haven't modified
a folio to the end, it cannot be contiguous with the following folio...
except if the dirty region of the folio is right at the end of the folio
space.
Fix the test to take the offset into the folio into account as well, such
that if the dirty region runs right up to the end of the folio, we leave
the flushing for later.
Fixes: 288ace2f57 ("netfs: New writeback implementation")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com> (DFS, global name space)
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20240620173137.610345-4-dhowells@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Instead of inventing a custom way to conditionally enable debugging,
just make use of pr_debug(), which also has dynamic debugging facilities
and is more likely known to someone who hunts a problem in the netfs
code. Also drop the module parameter netfs_debug which didn't have any
effect without further source changes. (The variable netfs_debug was
only used in #ifdef blocks for cpp vars that don't exist; Note that
CONFIG_NETFS_DEBUG isn't settable via kconfig, a variable with that name
never existed in the mainline and is probably just taken over (and
renamed) from similar custom debug logging implementations.)
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Link: https://lore.kernel.org/r/20240608151352.22860-2-ukleinek@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Merge tag 'vfs-6.10-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
- Fix io_uring based write-through after converting cifs to use the
netfs library
- Fix aio error handling when doing write-through via netfs library
- Fix performance regression in iomap when used with non-large folio
mappings
- Fix signalfd error code
- Remove obsolete comment in signalfd code
- Fix async request indication in netfs_perform_write() by raising
BDP_ASYNC when IOCB_NOWAIT is set
- Yield swap device immediately to prevent spurious EBUSY errors
- Don't cross a .backup mountpoint from backup volumes in afs to avoid
infinite loops
- Fix a race between umount and async request completion in 9p after 9p
was converted to use the netfs library
* tag 'vfs-6.10-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
netfs, 9p: Fix race between umount and async request completion
afs: Don't cross .backup mountpoint from backup volume
swap: yield device immediately
netfs: Fix setting of BDP_ASYNC from iocb flags
signalfd: drop an obsolete comment
signalfd: fix error return code
iomap: fault in smaller chunks for non-large folio mappings
filemap: add helper mapping_max_folio_size()
netfs: Fix AIO error handling when doing write-through
netfs: Fix io_uring based write-through
Fix netfs_perform_write() to set BDP_ASYNC if IOCB_NOWAIT is set rather
than if IOCB_SYNC is not set. It reflects asynchronicity in the sense of
not waiting rather than synchronicity in the sense of not returning until
the op is complete.
Without this, generic/590 fails on cifs in strict caching mode with a
complaint that one of the writes fails with EAGAIN. The test can be
distilled down to:
mount -t cifs /my/share /mnt -ostuff
xfs_io -i -c 'falloc 0 8191M -c fsync -f /mnt/file
xfs_io -i -c 'pwrite -b 1M -W 0 8191M' /mnt/file
Fixes: c38f4e96e6 ("netfs: Provide func to copy data to pagecache for buffered write")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/316306.1716306586@warthog.procyon.org.uk
Reviewed-by: Jens Axboe <axboe@kernel.dk>
cc: Jeff Layton <jlayton@kernel.org>
cc: Enzo Matsumiya <ematsumiya@suse.de>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
If an error occurs whilst we're doing an AIO write in write-through mode,
we may end up calling ->ki_complete() *and* returning an error from
->write_iter(). This can result in either a UAF (the ->ki_complete() func
pointer may get overwritten, for example) or a refcount underflow in
io_submit() as ->ki_complete is called twice.
Fix this by making netfs_end_writethrough() - and thus
netfs_perform_write() - unconditionally return -EIOCBQUEUED if we're doing
an AIO write and wait for completion if we're not.
Fixes: 288ace2f57 ("netfs: New writeback implementation")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/295052.1716298587@warthog.procyon.org.uk
cc: Jeff Layton <jlayton@kernel.org>
cc: Enzo Matsumiya <ematsumiya@suse.de>
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
This can be triggered by mounting a cifs filesystem with a cache=strict
mount option and then, using the fsx program from xfstests, doing:
ltp/fsx -A -d -N 1000 -S 11463 -P /tmp /cifs-mount/foo \
--replay-ops=gen112-fsxops
Where gen112-fsxops holds:
fallocate 0x6be7 0x8fc5 0x377d3
copy_range 0x9c71 0x77e8 0x2edaf 0x377d3
write 0x2776d 0x8f65 0x377d3
The problem is that netfs_io_request::len is being used for two purposes
and ends up getting set to the amount of data we transferred, not the
amount of data the caller asked to be transferred (for various reasons,
such as mmap'd writes, we might end up rounding out the data written to the
server to include the entire folio at each end).
Fix this by keeping the amount we were asked to write in ->len and using
->submitted to track what we issued ops for. Then, when we come to calling
->ki_complete(), ->len is the right size.
This also required netfs_cleanup_dio_write() to change since we're no
longer advancing wreq->len. Use wreq->transferred instead as we might have
done a short read.
With this, the generic/112 xfstest passes if cifs is forced to put all
non-DIO opens into write-through mode.
Fixes: 288ace2f57 ("netfs: New writeback implementation")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/295086.1716298663@warthog.procyon.org.uk
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <stfrench@microsoft.com>
cc: Enzo Matsumiya <ematsumiya@suse.de>
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
With the changes to folios/netfs it is now easier to reenable
swapfile support over SMB3 which fixes various xfstests
Reviewed-by: David Howells <dhowells@redhat.com>
Suggested-by: David Howells <dhowells@redhat.com>
Fixes: e1209d3a7a ("mm: introduce ->swap_rw and use it for reads from SWP_FS_OPS swap-space")
Signed-off-by: Steve French <stfrench@microsoft.com>
Fix to take the i_rwsem (through the netfs locking wrappers) before taking
cinode->lock_sem.
Fixes: 3ee1a1fc39 ("cifs: Cut over to using netfslib")
Reported-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Make the cifs filesystem use netfslib to handle reading and writing on
behalf of cifs. The changes include:
(1) Various read_iter/write_iter type functions are turned into wrappers
around netfslib API functions or are pointed directly at those
functions:
cifs_file_direct{,_nobrl}_ops switch to use
netfs_unbuffered_read_iter and netfs_unbuffered_write_iter.
Large pieces of code that will be removed are #if'd out and will be removed
in subsequent patches.
[?] Why does cifs mark the page dirty in the destination buffer of a DIO
read? Should that happen automatically? Does netfs need to do that?
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Provide implementation of the netfslib hooks that will be used by netfslib
to ask cifs to set up and perform operations. Of particular note are
(*) cifs_clamp_length() - This is used to negotiate the size of the next
subrequest in a read request, taking into account the credit available
and the rsize. The credits are attached to the subrequest.
(*) cifs_req_issue_read() - This is used to issue a subrequest that has
been set up and clamped.
(*) cifs_prepare_write() - This prepares to fill a subrequest by picking a
channel, reopening the file and requesting credits so that we can set
the maximum size of the subrequest and also sets the maximum number of
segments if we're doing RDMA.
(*) cifs_issue_write() - This releases any unneeded credits and issues an
asynchronous data write for the contiguous slice of file covered by
the subrequest. This should possibly be folded in to all
->async_writev() ops and that called directly.
(*) cifs_begin_writeback() - This gets the cached writable handle through
which we do writeback (this does not affect writethrough, unbuffered
or direct writes).
At this point, cifs is not wired up to actually *use* netfslib; that will
be done in a subsequent patch.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Use a hook in the new writeback code's retry algorithm to rotate the keys
once all the outstanding subreqs have failed rather than doing it
separately on each subreq.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Do a couple of miscellaneous tidy ups:
(1) Add a qualifier into a file banner comment.
(2) Put the writeback folio traces back into alphabetical order.
(3) Remove some unused folio traces.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Cut over to using the new writeback code. The old code is #ifdef'd out or
otherwise removed from compilation to avoid conflicts and will be removed
in a future patch.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Add some write-side stats to count buffered writes, buffered writethrough,
and writepages calls.
Whilst we're at it, clean up the naming on some of the existing stats
counters and organise the output into two sets.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
The current netfslib writeback implementation creates writeback requests of
contiguous folio data and then separately tiles subrequests over the space
twice, once for the server and once for the cache. This creates a few
issues:
(1) Every time there's a discontiguity or a change between writing to only
one destination or writing to both, it must create a new request.
This makes it harder to do vectored writes.
(2) The folios don't have the writeback mark removed until the end of the
request - and a request could be hundreds of megabytes.
(3) In future, I want to support a larger cache granularity, which will
require aggregation of some folios that contain unmodified data (which
only need to go to the cache) and some which contain modifications
(which need to be uploaded and stored to the cache) - but, currently,
these are treated as discontiguous.
There's also a move to get everyone to use writeback_iter() to extract
writable folios from the pagecache. That said, currently writeback_iter()
has some issues that make it less than ideal:
(1) there's no way to cancel the iteration, even if you find a "temporary"
error that means the current folio and all subsequent folios are going
to fail;
(2) there's no way to filter the folios being written back - something
that will impact Ceph with it's ordered snap system;
(3) and if you get a folio you can't immediately deal with (say you need
to flush the preceding writes), you are left with a folio hanging in
the locked state for the duration, when really we should unlock it and
relock it later.
In this new implementation, I use writeback_iter() to pump folios,
progressively creating two parallel, but separate streams and cleaning up
the finished folios as the subrequests complete. Either or both streams
can contain gaps, and the subrequests in each stream can be of variable
size, don't need to align with each other and don't need to align with the
folios.
Indeed, subrequests can cross folio boundaries, may cover several folios or
a folio may be spanned by multiple folios, e.g.:
+---+---+-----+-----+---+----------+
Folios: | | | | | | |
+---+---+-----+-----+---+----------+
+------+------+ +----+----+
Upload: | | |.....| | |
+------+------+ +----+----+
+------+------+------+------+------+
Cache: | | | | | |
+------+------+------+------+------+
The progressive subrequest construction permits the algorithm to be
preparing both the next upload to the server and the next write to the
cache whilst the previous ones are already in progress. Throttling can be
applied to control the rate of production of subrequests - and, in any
case, we probably want to write them to the server in ascending order,
particularly if the file will be extended.
Content crypto can also be prepared at the same time as the subrequests and
run asynchronously, with the prepped requests being stalled until the
crypto catches up with them. This might also be useful for transport
crypto, but that happens at a lower layer, so probably would be harder to
pull off.
The algorithm is split into three parts:
(1) The issuer. This walks through the data, packaging it up, encrypting
it and creating subrequests. The part of this that generates
subrequests only deals with file positions and spans and so is usable
for DIO/unbuffered writes as well as buffered writes.
(2) The collector. This asynchronously collects completed subrequests,
unlocks folios, frees crypto buffers and performs any retries. This
runs in a work queue so that the issuer can return to the caller for
writeback (so that the VM can have its kswapd thread back) or async
writes.
(3) The retryer. This pauses the issuer, waits for all outstanding
subrequests to complete and then goes through the failed subrequests
to reissue them. This may involve reprepping them (with cifs, the
credits must be renegotiated, and a subrequest may need splitting),
and doing RMW for content crypto if there's a conflicting change on
the server.
[!] Note that some of the functions are prefixed with "new_" to avoid
clashes with existing functions. These will be renamed in a later patch
that cuts over to the new algorithm.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Switch to using unsigned long long rather than loff_t in netfslib to avoid
problems with the sign flipping in the maths when we're dealing with the
byte at position 0x7fffffffffffffff.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Xiubo Li <xiubli@redhat.com>
cc: netfs@lists.linux.dev
cc: ceph-devel@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Use mempools for allocating requests and subrequests in an effort to make
sure that allocation always succeeds so that when performing writeback we
can always make progress.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Remove support for ->launder_folio() from netfslib and expect filesystems
to use filemap_invalidate_inode() instead. netfs_launder_folio() can then
be got rid of.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Steve French <sfrench@samba.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: devel@lists.orangefs.org
Implement a replacement for launder_folio. The key feature of
invalidate_inode_pages2() is that it locks each folio individually, unmaps
it to prevent mmap'd accesses interfering and calls the ->launder_folio()
address_space op to flush it. This has problems: firstly, each folio is
written individually as one or more small writes; secondly, adjacent folios
cannot be added so easily into the laundry; thirdly, it's yet another op to
implement.
Instead, use the invalidate lock to cause anyone wanting to add a folio to
the inode to wait, then unmap all the folios if we have mmaps, then,
conditionally, use ->writepages() to flush any dirty data back and then
discard all pages.
The invalidate lock prevents ->read_iter(), ->write_iter() and faulting
through mmap all from adding pages for the duration.
This is then used from netfslib to handle the flusing in unbuffered and
direct writes.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: Miklos Szeredi <miklos@szeredi.hu>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Andrew Morton <akpm@linux-foundation.org>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Christian Brauner <brauner@kernel.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: devel@lists.orangefs.org
Use the subreq_counter in netfs_io_request to allocate subrequest
debug_index values in read ops as well as write ops.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Make the netfs_io_request::subreq_counter, used to generate values for
netfs_io_subrequest::debug_index, into an atomic_t so that it can be called
from the retry thread at the same time as the app thread issuing writes.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Remove the deprecated use of PG_private_2 in netfslib.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Remove the PG_fscache alias for PG_private_2 and use the latter directly.
Use of this flag for marking pages undergoing writing to the cache should
be considered deprecated and the folios should be marked dirty instead and
the write done in ->writepages().
Note that PG_private_2 itself should be considered deprecated and up for
future removal by the MM folks too.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Xiubo Li <xiubli@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: Tom Talpey <tom@talpey.com>
cc: Bharath SM <bharathsm@microsoft.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: Anna Schumaker <anna@kernel.org>
cc: netfs@lists.linux.dev
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
When dirty data is being written to the cache, setting/waiting on/clearing
the fscache flag is always done in tandem with setting/waiting on/clearing
the writeback flag. The netfslib buffered write routines wait on and set
both flags and the write request cleanup clears both flags, so the fscache
flag is almost superfluous.
The reason it isn't superfluous is because the fscache flag is also used to
indicate that data just read from the server is being written to the cache.
The flag is used to prevent a race involving overlapping direct-I/O writes
to the cache.
Change this to indicate that a page is in need of being copied to the cache
by placing a magic value in folio->private and marking the folios dirty.
Then when the writeback code sees a folio marked in this way, it only
writes it to the cache and not to the server.
If a folio that has this magic value set is modified, the value is just
replaced and the folio will then be uplodaded too.
With this, PG_fscache is no longer required by the netfslib core, 9p and
afs.
Ceph and nfs, however, still need to use the old PG_fscache-based tracking.
To deal with this, a flag, NETFS_ICTX_USE_PGPRIV2, now has to be set on the
flags in the netfs_inode struct for those filesystems. This reenables the
use of PG_fscache in that inode. 9p and afs use the netfslib write helpers
so get switched over; cifs, for the moment, does page-by-page manual access
to the cache, so doesn't use PG_fscache and is unaffected.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Xiubo Li <xiubli@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: Tom Talpey <tom@talpey.com>
cc: Bharath SM <bharathsm@microsoft.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: Anna Schumaker <anna@kernel.org>
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Update i_blocks when i_size is updated when we finish making a write to the
pagecache to reflect the amount of space we think will be consumed.
This maintains cifs commit dbfdff402d ("smb3:
update allocation size more accurately on write completion") which would
otherwise be removed by the cifs part of the netfs writeback rewrite.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
In netfs_perform_write(), when the file is marked NETFS_ICTX_WRITETHROUGH
or O_*SYNC or RWF_*SYNC was specified, write-through caching is performed
on a buffered file. When setting up for write-through, we flush any
conflicting writes in the region and wait for the write to complete,
failing if there's a write error to return.
The issue arises if we're writing at or above the EOF position because we
skip the flush and - more importantly - the wait. This becomes a problem
if there's a partial folio at the end of the file that is being written out
and we want to make a write to it too. Both the already-running write and
the write we start both want to clear the writeback mark, but whoever is
second causes a warning looking something like:
------------[ cut here ]------------
R=00000012: folio 11 is not under writeback
WARNING: CPU: 34 PID: 654 at fs/netfs/write_collect.c:105
...
CPU: 34 PID: 654 Comm: kworker/u386:27 Tainted: G S ...
...
Workqueue: events_unbound netfs_write_collection_worker
...
RIP: 0010:netfs_writeback_lookup_folio
Fix this by making the flush-and-wait unconditional. It will do nothing if
there are no folios in the pagecache and will return quickly if there are
no folios in the region specified.
Further, move the WBC attachment above the flush call as the flush is going
to attach a WBC and detach it again if it is not present - and since we
need one anyway we might as well share it.
Fixes: 41d8e7673a ("netfs: Implement a write-through caching option")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404161031.468b84f-oliver.sang@intel.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/2150448.1714130115@warthog.procyon.org.uk
Reviewed-by: Jeffrey Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Fix the error return in netfs_perform_write() acting in writethrough-mode
to return any cached error in the case that netfs_end_writethrough()
returns 0.
This can affect the use of O_SYNC/O_DSYNC/RWF_SYNC/RWF_DSYNC in 9p and afs.
Fixes: 41d8e7673a ("netfs: Implement a write-through caching option")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/6736.1713343639@warthog.procyon.org.uk
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
