<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs/fuse, branch linux-6.15.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>fuse: fix runtime warning on truncate_folio_batch_exceptionals()</title>
<updated>2025-07-06T09:04:12+00:00</updated>
<author>
<name>Haiyue Wang</name>
<email>haiyuewa@163.com</email>
</author>
<published>2025-06-21T17:13:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b48878aee8e7311411148c7a67c8f0b02f571d75'/>
<id>b48878aee8e7311411148c7a67c8f0b02f571d75</id>
<content type='text'>
commit befd9a71d859ea625eaa84dae1b243efb3df3eca upstream.

The WARN_ON_ONCE is introduced on truncate_folio_batch_exceptionals() to
capture whether the filesystem has removed all DAX entries or not.

And the fix has been applied on the filesystem xfs and ext4 by the commit
0e2f80afcfa6 ("fs/dax: ensure all pages are idle prior to filesystem
unmount").

Apply the missed fix on filesystem fuse to fix the runtime warning:

[    2.011450] ------------[ cut here ]------------
[    2.011873] WARNING: CPU: 0 PID: 145 at mm/truncate.c:89 truncate_folio_batch_exceptionals+0x272/0x2b0
[    2.012468] Modules linked in:
[    2.012718] CPU: 0 UID: 1000 PID: 145 Comm: weston Not tainted 6.16.0-rc2-WSL2-STABLE #2 PREEMPT(undef)
[    2.013292] RIP: 0010:truncate_folio_batch_exceptionals+0x272/0x2b0
[    2.013704] Code: 48 63 d0 41 29 c5 48 8d 1c d5 00 00 00 00 4e 8d 6c 2a 01 49 c1 e5 03 eb 09 48 83 c3 08 49 39 dd 74 83 41 f6 44 1c 08 01 74 ef &lt;0f&gt; 0b 49 8b 34 1e 48 89 ef e8 10 a2 17 00 eb df 48 8b 7d 00 e8 35
[    2.014845] RSP: 0018:ffffa47ec33f3b10 EFLAGS: 00010202
[    2.015279] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[    2.015884] RDX: 0000000000000000 RSI: ffffa47ec33f3ca0 RDI: ffff98aa44f3fa80
[    2.016377] RBP: ffff98aa44f3fbf0 R08: ffffa47ec33f3ba8 R09: 0000000000000000
[    2.016942] R10: 0000000000000001 R11: 0000000000000000 R12: ffffa47ec33f3ca0
[    2.017437] R13: 0000000000000008 R14: ffffa47ec33f3ba8 R15: 0000000000000000
[    2.017972] FS:  000079ce006afa40(0000) GS:ffff98aade441000(0000) knlGS:0000000000000000
[    2.018510] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    2.018987] CR2: 000079ce03e74000 CR3: 000000010784f006 CR4: 0000000000372eb0
[    2.019518] Call Trace:
[    2.019729]  &lt;TASK&gt;
[    2.019901]  truncate_inode_pages_range+0xd8/0x400
[    2.020280]  ? timerqueue_add+0x66/0xb0
[    2.020574]  ? get_nohz_timer_target+0x2a/0x140
[    2.020904]  ? timerqueue_add+0x66/0xb0
[    2.021231]  ? timerqueue_del+0x2e/0x50
[    2.021646]  ? __remove_hrtimer+0x39/0x90
[    2.022017]  ? srso_alias_untrain_ret+0x1/0x10
[    2.022497]  ? psi_group_change+0x136/0x350
[    2.023046]  ? _raw_spin_unlock+0xe/0x30
[    2.023514]  ? finish_task_switch.isra.0+0x8d/0x280
[    2.024068]  ? __schedule+0x532/0xbd0
[    2.024551]  fuse_evict_inode+0x29/0x190
[    2.025131]  evict+0x100/0x270
[    2.025641]  ? _atomic_dec_and_lock+0x39/0x50
[    2.026316]  ? __pfx_generic_delete_inode+0x10/0x10
[    2.026843]  __dentry_kill+0x71/0x180
[    2.027335]  dput+0xeb/0x1b0
[    2.027725]  __fput+0x136/0x2b0
[    2.028054]  __x64_sys_close+0x3d/0x80
[    2.028469]  do_syscall_64+0x6d/0x1b0
[    2.028832]  ? clear_bhb_loop+0x30/0x80
[    2.029182]  ? clear_bhb_loop+0x30/0x80
[    2.029533]  ? clear_bhb_loop+0x30/0x80
[    2.029902]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[    2.030423] RIP: 0033:0x79ce03d0d067
[    2.030820] Code: b8 ff ff ff ff e9 3e ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 &lt;48&gt; 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 a7 f8 ff
[    2.032354] RSP: 002b:00007ffef0498948 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
[    2.032939] RAX: ffffffffffffffda RBX: 00007ffef0498960 RCX: 000079ce03d0d067
[    2.033612] RDX: 0000000000000003 RSI: 0000000000001000 RDI: 000000000000000d
[    2.034289] RBP: 00007ffef0498a30 R08: 000000000000000d R09: 0000000000000000
[    2.034944] R10: 00007ffef0498978 R11: 0000000000000246 R12: 0000000000000001
[    2.035610] R13: 00007ffef0498960 R14: 000079ce03e09ce0 R15: 0000000000000003
[    2.036301]  &lt;/TASK&gt;
[    2.036532] ---[ end trace 0000000000000000 ]---

Link: https://lkml.kernel.org/r/20250621171507.3770-1-haiyuewa@163.com
Fixes: bde708f1a65d ("fs/dax: always remove DAX page-cache entries when breaking layouts")
Signed-off-by: Haiyue Wang &lt;haiyuewa@163.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Miklos Szeredi &lt;miklos@szeredi.hu&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit befd9a71d859ea625eaa84dae1b243efb3df3eca upstream.

The WARN_ON_ONCE is introduced on truncate_folio_batch_exceptionals() to
capture whether the filesystem has removed all DAX entries or not.

And the fix has been applied on the filesystem xfs and ext4 by the commit
0e2f80afcfa6 ("fs/dax: ensure all pages are idle prior to filesystem
unmount").

Apply the missed fix on filesystem fuse to fix the runtime warning:

[    2.011450] ------------[ cut here ]------------
[    2.011873] WARNING: CPU: 0 PID: 145 at mm/truncate.c:89 truncate_folio_batch_exceptionals+0x272/0x2b0
[    2.012468] Modules linked in:
[    2.012718] CPU: 0 UID: 1000 PID: 145 Comm: weston Not tainted 6.16.0-rc2-WSL2-STABLE #2 PREEMPT(undef)
[    2.013292] RIP: 0010:truncate_folio_batch_exceptionals+0x272/0x2b0
[    2.013704] Code: 48 63 d0 41 29 c5 48 8d 1c d5 00 00 00 00 4e 8d 6c 2a 01 49 c1 e5 03 eb 09 48 83 c3 08 49 39 dd 74 83 41 f6 44 1c 08 01 74 ef &lt;0f&gt; 0b 49 8b 34 1e 48 89 ef e8 10 a2 17 00 eb df 48 8b 7d 00 e8 35
[    2.014845] RSP: 0018:ffffa47ec33f3b10 EFLAGS: 00010202
[    2.015279] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[    2.015884] RDX: 0000000000000000 RSI: ffffa47ec33f3ca0 RDI: ffff98aa44f3fa80
[    2.016377] RBP: ffff98aa44f3fbf0 R08: ffffa47ec33f3ba8 R09: 0000000000000000
[    2.016942] R10: 0000000000000001 R11: 0000000000000000 R12: ffffa47ec33f3ca0
[    2.017437] R13: 0000000000000008 R14: ffffa47ec33f3ba8 R15: 0000000000000000
[    2.017972] FS:  000079ce006afa40(0000) GS:ffff98aade441000(0000) knlGS:0000000000000000
[    2.018510] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    2.018987] CR2: 000079ce03e74000 CR3: 000000010784f006 CR4: 0000000000372eb0
[    2.019518] Call Trace:
[    2.019729]  &lt;TASK&gt;
[    2.019901]  truncate_inode_pages_range+0xd8/0x400
[    2.020280]  ? timerqueue_add+0x66/0xb0
[    2.020574]  ? get_nohz_timer_target+0x2a/0x140
[    2.020904]  ? timerqueue_add+0x66/0xb0
[    2.021231]  ? timerqueue_del+0x2e/0x50
[    2.021646]  ? __remove_hrtimer+0x39/0x90
[    2.022017]  ? srso_alias_untrain_ret+0x1/0x10
[    2.022497]  ? psi_group_change+0x136/0x350
[    2.023046]  ? _raw_spin_unlock+0xe/0x30
[    2.023514]  ? finish_task_switch.isra.0+0x8d/0x280
[    2.024068]  ? __schedule+0x532/0xbd0
[    2.024551]  fuse_evict_inode+0x29/0x190
[    2.025131]  evict+0x100/0x270
[    2.025641]  ? _atomic_dec_and_lock+0x39/0x50
[    2.026316]  ? __pfx_generic_delete_inode+0x10/0x10
[    2.026843]  __dentry_kill+0x71/0x180
[    2.027335]  dput+0xeb/0x1b0
[    2.027725]  __fput+0x136/0x2b0
[    2.028054]  __x64_sys_close+0x3d/0x80
[    2.028469]  do_syscall_64+0x6d/0x1b0
[    2.028832]  ? clear_bhb_loop+0x30/0x80
[    2.029182]  ? clear_bhb_loop+0x30/0x80
[    2.029533]  ? clear_bhb_loop+0x30/0x80
[    2.029902]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[    2.030423] RIP: 0033:0x79ce03d0d067
[    2.030820] Code: b8 ff ff ff ff e9 3e ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 &lt;48&gt; 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 a7 f8 ff
[    2.032354] RSP: 002b:00007ffef0498948 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
[    2.032939] RAX: ffffffffffffffda RBX: 00007ffef0498960 RCX: 000079ce03d0d067
[    2.033612] RDX: 0000000000000003 RSI: 0000000000001000 RDI: 000000000000000d
[    2.034289] RBP: 00007ffef0498a30 R08: 000000000000000d R09: 0000000000000000
[    2.034944] R10: 00007ffef0498978 R11: 0000000000000246 R12: 0000000000000001
[    2.035610] R13: 00007ffef0498960 R14: 000079ce03e09ce0 R15: 0000000000000003
[    2.036301]  &lt;/TASK&gt;
[    2.036532] ---[ end trace 0000000000000000 ]---

Link: https://lkml.kernel.org/r/20250621171507.3770-1-haiyuewa@163.com
Fixes: bde708f1a65d ("fs/dax: always remove DAX page-cache entries when breaking layouts")
Signed-off-by: Haiyue Wang &lt;haiyuewa@163.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Miklos Szeredi &lt;miklos@szeredi.hu&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fuse: fix race between concurrent setattrs from multiple nodes</title>
<updated>2025-07-06T09:04:04+00:00</updated>
<author>
<name>Guang Yuan Wu</name>
<email>gwu@ddn.com</email>
</author>
<published>2025-05-02T04:04:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d7b3ec35f0429a73c47bd8d7b82e88f165940e20'/>
<id>d7b3ec35f0429a73c47bd8d7b82e88f165940e20</id>
<content type='text'>
[ Upstream commit 69efbff69f89c9b2b72c4d82ad8b59706add768a ]

When mounting a user-space filesystem on multiple clients, after
concurrent -&gt;setattr() calls from different node, stale inode
attributes may be cached in some node.

This is caused by fuse_setattr() racing with
fuse_reverse_inval_inode().

When filesystem server receives setattr request, the client node
with valid iattr cached will be required to update the fuse_inode's
attr_version and invalidate the cache by fuse_reverse_inval_inode(),
and at the next call to -&gt;getattr() they will be fetched from user
space.

The race scenario is:
1. client-1 sends setattr (iattr-1) request to server
2. client-1 receives the reply from server
3. before client-1 updates iattr-1 to the cached attributes by
   fuse_change_attributes_common(), server receives another setattr
   (iattr-2) request from client-2
4. server requests client-1 to update the inode attr_version and
   invalidate the cached iattr, and iattr-1 becomes staled
5. client-2 receives the reply from server, and caches iattr-2
6. continue with step 2, client-1 invokes
   fuse_change_attributes_common(), and caches iattr-1

The issue has been observed from concurrent of chmod, chown, or
truncate, which all invoke -&gt;setattr() call.

The solution is to use fuse_inode's attr_version to check whether
the attributes have been modified during the setattr request's
lifetime.  If so, mark the attributes as invalid in the function
fuse_change_attributes_common().

Signed-off-by: Guang Yuan Wu &lt;gwu@ddn.com&gt;
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 69efbff69f89c9b2b72c4d82ad8b59706add768a ]

When mounting a user-space filesystem on multiple clients, after
concurrent -&gt;setattr() calls from different node, stale inode
attributes may be cached in some node.

This is caused by fuse_setattr() racing with
fuse_reverse_inval_inode().

When filesystem server receives setattr request, the client node
with valid iattr cached will be required to update the fuse_inode's
attr_version and invalidate the cache by fuse_reverse_inval_inode(),
and at the next call to -&gt;getattr() they will be fetched from user
space.

The race scenario is:
1. client-1 sends setattr (iattr-1) request to server
2. client-1 receives the reply from server
3. before client-1 updates iattr-1 to the cached attributes by
   fuse_change_attributes_common(), server receives another setattr
   (iattr-2) request from client-2
4. server requests client-1 to update the inode attr_version and
   invalidate the cached iattr, and iattr-1 becomes staled
5. client-2 receives the reply from server, and caches iattr-2
6. continue with step 2, client-1 invokes
   fuse_change_attributes_common(), and caches iattr-1

The issue has been observed from concurrent of chmod, chown, or
truncate, which all invoke -&gt;setattr() call.

The solution is to use fuse_inode's attr_version to check whether
the attributes have been modified during the setattr request's
lifetime.  If so, mark the attributes as invalid in the function
fuse_change_attributes_common().

Signed-off-by: Guang Yuan Wu &lt;gwu@ddn.com&gt;
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>virtiofs: add filesystem context source name check</title>
<updated>2025-04-07T13:22:25+00:00</updated>
<author>
<name>Xiangsheng Hou</name>
<email>xiangsheng.hou@mediatek.com</email>
</author>
<published>2025-04-07T11:50:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a94fd938df2b1628da66b498aa0eeb89593bc7a2'/>
<id>a94fd938df2b1628da66b498aa0eeb89593bc7a2</id>
<content type='text'>
In certain scenarios, for example, during fuzz testing, the source
name may be NULL, which could lead to a kernel panic. Therefore, an
extra check for the source name should be added.

Fixes: a62a8ef9d97d ("virtio-fs: add virtiofs filesystem")
Cc: &lt;stable@vger.kernel.org&gt; # all LTS kernels
Signed-off-by: Xiangsheng Hou &lt;xiangsheng.hou@mediatek.com&gt;
Link: https://lore.kernel.org/20250407115111.25535-1-xiangsheng.hou@mediatek.com
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In certain scenarios, for example, during fuzz testing, the source
name may be NULL, which could lead to a kernel panic. Therefore, an
extra check for the source name should be added.

Fixes: a62a8ef9d97d ("virtio-fs: add virtiofs filesystem")
Cc: &lt;stable@vger.kernel.org&gt; # all LTS kernels
Signed-off-by: Xiangsheng Hou &lt;xiangsheng.hou@mediatek.com&gt;
Link: https://lore.kernel.org/20250407115111.25535-1-xiangsheng.hou@mediatek.com
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'fuse-update-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse</title>
<updated>2025-04-02T23:36:59+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-04-02T23:36:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5e17b5c71729d8ce936c83a579ed45f65efcb456'/>
<id>5e17b5c71729d8ce936c83a579ed45f65efcb456</id>
<content type='text'>
Pull fuse updates from Miklos Szeredi:

 - Allow connection to server to time out (Joanne Koong)

 - If server doesn't support creating a hard link, return EPERM rather
   than ENOSYS (Matt Johnston)

 - Allow file names longer than 1024 chars (Bernd Schubert)

 - Fix a possible race if request on io_uring queue is interrupted
   (Bernd Schubert)

 - Misc fixes and cleanups

* tag 'fuse-update-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: remove unneeded atomic set in uring creation
  fuse: fix uring race condition for null dereference of fc
  fuse: Increase FUSE_NAME_MAX to PATH_MAX
  fuse: Allocate only namelen buf memory in fuse_notify_
  fuse: add default_request_timeout and max_request_timeout sysctls
  fuse: add kernel-enforced timeout option for requests
  fuse: optmize missing FUSE_LINK support
  fuse: Return EPERM rather than ENOSYS from link()
  fuse: removed unused function fuse_uring_create() from header
  fuse: {io-uring} Fix a possible req cancellation race
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull fuse updates from Miklos Szeredi:

 - Allow connection to server to time out (Joanne Koong)

 - If server doesn't support creating a hard link, return EPERM rather
   than ENOSYS (Matt Johnston)

 - Allow file names longer than 1024 chars (Bernd Schubert)

 - Fix a possible race if request on io_uring queue is interrupted
   (Bernd Schubert)

 - Misc fixes and cleanups

* tag 'fuse-update-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: remove unneeded atomic set in uring creation
  fuse: fix uring race condition for null dereference of fc
  fuse: Increase FUSE_NAME_MAX to PATH_MAX
  fuse: Allocate only namelen buf memory in fuse_notify_
  fuse: add default_request_timeout and max_request_timeout sysctls
  fuse: add kernel-enforced timeout option for requests
  fuse: optmize missing FUSE_LINK support
  fuse: Return EPERM rather than ENOSYS from link()
  fuse: removed unused function fuse_uring_create() from header
  fuse: {io-uring} Fix a possible req cancellation race
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2025-04-01T16:29:18+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-04-01T16:29:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eb0ece16027f8223d5dc9aaf90124f70577bd22a'/>
<id>eb0ece16027f8223d5dc9aaf90124f70577bd22a</id>
<content type='text'>
Pull MM updates from Andrew Morton:

 - The series "Enable strict percpu address space checks" from Uros
   Bizjak uses x86 named address space qualifiers to provide
   compile-time checking of percpu area accesses.

   This has caused a small amount of fallout - two or three issues were
   reported. In all cases the calling code was found to be incorrect.

 - The series "Some cleanup for memcg" from Chen Ridong implements some
   relatively monir cleanups for the memcontrol code.

 - The series "mm: fixes for device-exclusive entries (hmm)" from David
   Hildenbrand fixes a boatload of issues which David found then using
   device-exclusive PTE entries when THP is enabled. More work is
   needed, but this makes thins better - our own HMM selftests now
   succeed.

 - The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
   remove the z3fold and zbud implementations. They have been deprecated
   for half a year and nobody has complained.

 - The series "mm: further simplify VMA merge operation" from Lorenzo
   Stoakes implements numerous simplifications in this area. No runtime
   effects are anticipated.

 - The series "mm/madvise: remove redundant mmap_lock operations from
   process_madvise()" from SeongJae Park rationalizes the locking in the
   madvise() implementation. Performance gains of 20-25% were observed
   in one MADV_DONTNEED microbenchmark.

 - The series "Tiny cleanup and improvements about SWAP code" from
   Baoquan He contains a number of touchups to issues which Baoquan
   noticed when working on the swap code.

 - The series "mm: kmemleak: Usability improvements" from Catalin
   Marinas implements a couple of improvements to the kmemleak
   user-visible output.

 - The series "mm/damon/paddr: fix large folios access and schemes
   handling" from Usama Arif provides a couple of fixes for DAMON's
   handling of large folios.

 - The series "mm/damon/core: fix wrong and/or useless damos_walk()
   behaviors" from SeongJae Park fixes a few issues with the accuracy of
   kdamond's walking of DAMON regions.

 - The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
   Stoakes changes the interaction between framebuffer deferred-io and
   core MM. No functional changes are anticipated - this is preparatory
   work for the future removal of page structure fields.

 - The series "mm/damon: add support for hugepage_size DAMOS filter"
   from Usama Arif adds a DAMOS filter which permits the filtering by
   huge page sizes.

 - The series "mm: permit guard regions for file-backed/shmem mappings"
   from Lorenzo Stoakes extends the guard region feature from its
   present "anon mappings only" state. The feature now covers shmem and
   file-backed mappings.

 - The series "mm: batched unmap lazyfree large folios during
   reclamation" from Barry Song cleans up and speeds up the unmapping
   for pte-mapped large folios.

 - The series "reimplement per-vma lock as a refcount" from Suren
   Baghdasaryan puts the vm_lock back into the vma. Our reasons for
   pulling it out were largely bogus and that change made the code more
   messy. This patchset provides small (0-10%) improvements on one
   microbenchmark.

 - The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
   improves" from SeongJae Park does some maintenance work on the DAMON
   docs.

 - The series "hugetlb/CMA improvements for large systems" from Frank
   van der Linden addresses a pile of issues which have been observed
   when using CMA on large machines.

 - The series "mm/damon: introduce DAMOS filter type for unmapped pages"
   from SeongJae Park enables users of DMAON/DAMOS to filter my the
   page's mapped/unmapped status.

 - The series "zsmalloc/zram: there be preemption" from Sergey
   Senozhatsky teaches zram to run its compression and decompression
   operations preemptibly.

 - The series "selftests/mm: Some cleanups from trying to run them" from
   Brendan Jackman fixes a pile of unrelated issues which Brendan
   encountered while runnimg our selftests.

 - The series "fs/proc/task_mmu: add guard region bit to pagemap" from
   Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
   determine whether a particular page is a guard page.

 - The series "mm, swap: remove swap slot cache" from Kairui Song
   removes the swap slot cache from the allocation path - it simply
   wasn't being effective.

 - The series "mm: cleanups for device-exclusive entries (hmm)" from
   David Hildenbrand implements a number of unrelated cleanups in this
   code.

 - The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
   implements a number of preparatoty cleanups to the GENERIC_PTDUMP
   Kconfig logic.

 - The series "mm/damon: auto-tune aggregation interval" from SeongJae
   Park implements a feedback-driven automatic tuning feature for
   DAMON's aggregation interval tuning.

 - The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
   powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
   preparation for implementing lazy mmu mode for arm64 to optimize
   vmalloc.

 - The series "mm/page_alloc: Some clarifications for migratetype
   fallback" from Brendan Jackman reworks some commentary to make the
   code easier to follow.

 - The series "page_counter cleanup and size reduction" from Shakeel
   Butt cleans up the page_counter code and fixes a size increase which
   we accidentally added late last year.

 - The series "Add a command line option that enables control of how
   many threads should be used to allocate huge pages" from Thomas
   Prescher does that. It allows the careful operator to significantly
   reduce boot time by tuning the parallalization of huge page
   initialization.

 - The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
   from Tang Yizhou fixes the tracing output from the dirty page
   balancing code.

 - The series "mm/damon: make allow filters after reject filters useful
   and intuitive" from SeongJae Park improves the handling of allow and
   reject filters. Behaviour is made more consistent and the documention
   is updated accordingly.

 - The series "Switch zswap to object read/write APIs" from Yosry Ahmed
   updates zswap to the new object read/write APIs and thus permits the
   removal of some legacy code from zpool and zsmalloc.

 - The series "Some trivial cleanups for shmem" from Baolin Wang does as
   it claims.

 - The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
   Alistair Popple regularizes the weird ZONE_DEVICE page refcount
   handling in DAX, permittig the removal of a number of special-case
   checks.

 - The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
   preparatoty refactoring and cleanup of the mremap() code.

 - The series "mm: MM owner tracking for large folios (!hugetlb) +
   CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
   which we determine whether a large folio is known to be mapped
   exclusively into a single MM.

 - The series "mm/damon: add sysfs dirs for managing DAMOS filters based
   on handling layers" from SeongJae Park adds a couple of new sysfs
   directories to ease the management of DAMON/DAMOS filters.

 - The series "arch, mm: reduce code duplication in mem_init()" from
   Mike Rapoport consolidates many per-arch implementations of
   mem_init() into code generic code, where that is practical.

 - The series "mm/damon/sysfs: commit parameters online via
   damon_call()" from SeongJae Park continues the cleaning up of sysfs
   access to DAMON internal data.

 - The series "mm: page_ext: Introduce new iteration API" from Luiz
   Capitulino reworks the page_ext initialization to fix a boot-time
   crash which was observed with an unusual combination of compile and
   cmdline options.

 - The series "Buddy allocator like (or non-uniform) folio split" from
   Zi Yan reworks the code to split a folio into smaller folios. The
   main benefit is lessened memory consumption: fewer post-split folios
   are generated.

 - The series "Minimize xa_node allocation during xarry split" from Zi
   Yan reduces the number of xarray xa_nodes which are generated during
   an xarray split.

 - The series "drivers/base/memory: Two cleanups" from Gavin Shan
   performs some maintenance work on the drivers/base/memory code.

 - The series "Add tracepoints for lowmem reserves, watermarks and
   totalreserve_pages" from Martin Liu adds some more tracepoints to the
   page allocator code.

 - The series "mm/madvise: cleanup requests validations and
   classifications" from SeongJae Park cleans up some warts which
   SeongJae observed during his earlier madvise work.

 - The series "mm/hwpoison: Fix regressions in memory failure handling"
   from Shuai Xue addresses two quite serious regressions which Shuai
   has observed in the memory-failure implementation.

 - The series "mm: reliable huge page allocator" from Johannes Weiner
   makes huge page allocations cheaper and more reliable by reducing
   fragmentation.

 - The series "Minor memcg cleanups &amp; prep for memdescs" from Matthew
   Wilcox is preparatory work for the future implementation of memdescs.

 - The series "track memory used by balloon drivers" from Nico Pache
   introduces a way to track memory used by our various balloon drivers.

 - The series "mm/damon: introduce DAMOS filter type for active pages"
   from Nhat Pham permits users to filter for active/inactive pages,
   separately for file and anon pages.

 - The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
   separates the proactive reclaim statistics from the direct reclaim
   statistics.

 - The series "mm/vmscan: don't try to reclaim hwpoison folio" from
   Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
   code.

* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
  mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
  x86/mm: restore early initialization of high_memory for 32-bits
  mm/vmscan: don't try to reclaim hwpoison folio
  mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
  cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
  mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
  selftests/mm: speed up split_huge_page_test
  selftests/mm: uffd-unit-tests support for hugepages &gt; 2M
  docs/mm/damon/design: document active DAMOS filter type
  mm/damon: implement a new DAMOS filter type for active pages
  fs/dax: don't disassociate zero page entries
  MM documentation: add "Unaccepted" meminfo entry
  selftests/mm: add commentary about 9pfs bugs
  fork: use __vmalloc_node() for stack allocation
  docs/mm: Physical Memory: Populate the "Zones" section
  xen: balloon: update the NR_BALLOON_PAGES state
  hv_balloon: update the NR_BALLOON_PAGES state
  balloon_compaction: update the NR_BALLOON_PAGES state
  meminfo: add a per node counter for balloon drivers
  mm: remove references to folio in __memcg_kmem_uncharge_page()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull MM updates from Andrew Morton:

 - The series "Enable strict percpu address space checks" from Uros
   Bizjak uses x86 named address space qualifiers to provide
   compile-time checking of percpu area accesses.

   This has caused a small amount of fallout - two or three issues were
   reported. In all cases the calling code was found to be incorrect.

 - The series "Some cleanup for memcg" from Chen Ridong implements some
   relatively monir cleanups for the memcontrol code.

 - The series "mm: fixes for device-exclusive entries (hmm)" from David
   Hildenbrand fixes a boatload of issues which David found then using
   device-exclusive PTE entries when THP is enabled. More work is
   needed, but this makes thins better - our own HMM selftests now
   succeed.

 - The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
   remove the z3fold and zbud implementations. They have been deprecated
   for half a year and nobody has complained.

 - The series "mm: further simplify VMA merge operation" from Lorenzo
   Stoakes implements numerous simplifications in this area. No runtime
   effects are anticipated.

 - The series "mm/madvise: remove redundant mmap_lock operations from
   process_madvise()" from SeongJae Park rationalizes the locking in the
   madvise() implementation. Performance gains of 20-25% were observed
   in one MADV_DONTNEED microbenchmark.

 - The series "Tiny cleanup and improvements about SWAP code" from
   Baoquan He contains a number of touchups to issues which Baoquan
   noticed when working on the swap code.

 - The series "mm: kmemleak: Usability improvements" from Catalin
   Marinas implements a couple of improvements to the kmemleak
   user-visible output.

 - The series "mm/damon/paddr: fix large folios access and schemes
   handling" from Usama Arif provides a couple of fixes for DAMON's
   handling of large folios.

 - The series "mm/damon/core: fix wrong and/or useless damos_walk()
   behaviors" from SeongJae Park fixes a few issues with the accuracy of
   kdamond's walking of DAMON regions.

 - The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
   Stoakes changes the interaction between framebuffer deferred-io and
   core MM. No functional changes are anticipated - this is preparatory
   work for the future removal of page structure fields.

 - The series "mm/damon: add support for hugepage_size DAMOS filter"
   from Usama Arif adds a DAMOS filter which permits the filtering by
   huge page sizes.

 - The series "mm: permit guard regions for file-backed/shmem mappings"
   from Lorenzo Stoakes extends the guard region feature from its
   present "anon mappings only" state. The feature now covers shmem and
   file-backed mappings.

 - The series "mm: batched unmap lazyfree large folios during
   reclamation" from Barry Song cleans up and speeds up the unmapping
   for pte-mapped large folios.

 - The series "reimplement per-vma lock as a refcount" from Suren
   Baghdasaryan puts the vm_lock back into the vma. Our reasons for
   pulling it out were largely bogus and that change made the code more
   messy. This patchset provides small (0-10%) improvements on one
   microbenchmark.

 - The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
   improves" from SeongJae Park does some maintenance work on the DAMON
   docs.

 - The series "hugetlb/CMA improvements for large systems" from Frank
   van der Linden addresses a pile of issues which have been observed
   when using CMA on large machines.

 - The series "mm/damon: introduce DAMOS filter type for unmapped pages"
   from SeongJae Park enables users of DMAON/DAMOS to filter my the
   page's mapped/unmapped status.

 - The series "zsmalloc/zram: there be preemption" from Sergey
   Senozhatsky teaches zram to run its compression and decompression
   operations preemptibly.

 - The series "selftests/mm: Some cleanups from trying to run them" from
   Brendan Jackman fixes a pile of unrelated issues which Brendan
   encountered while runnimg our selftests.

 - The series "fs/proc/task_mmu: add guard region bit to pagemap" from
   Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
   determine whether a particular page is a guard page.

 - The series "mm, swap: remove swap slot cache" from Kairui Song
   removes the swap slot cache from the allocation path - it simply
   wasn't being effective.

 - The series "mm: cleanups for device-exclusive entries (hmm)" from
   David Hildenbrand implements a number of unrelated cleanups in this
   code.

 - The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
   implements a number of preparatoty cleanups to the GENERIC_PTDUMP
   Kconfig logic.

 - The series "mm/damon: auto-tune aggregation interval" from SeongJae
   Park implements a feedback-driven automatic tuning feature for
   DAMON's aggregation interval tuning.

 - The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
   powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
   preparation for implementing lazy mmu mode for arm64 to optimize
   vmalloc.

 - The series "mm/page_alloc: Some clarifications for migratetype
   fallback" from Brendan Jackman reworks some commentary to make the
   code easier to follow.

 - The series "page_counter cleanup and size reduction" from Shakeel
   Butt cleans up the page_counter code and fixes a size increase which
   we accidentally added late last year.

 - The series "Add a command line option that enables control of how
   many threads should be used to allocate huge pages" from Thomas
   Prescher does that. It allows the careful operator to significantly
   reduce boot time by tuning the parallalization of huge page
   initialization.

 - The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
   from Tang Yizhou fixes the tracing output from the dirty page
   balancing code.

 - The series "mm/damon: make allow filters after reject filters useful
   and intuitive" from SeongJae Park improves the handling of allow and
   reject filters. Behaviour is made more consistent and the documention
   is updated accordingly.

 - The series "Switch zswap to object read/write APIs" from Yosry Ahmed
   updates zswap to the new object read/write APIs and thus permits the
   removal of some legacy code from zpool and zsmalloc.

 - The series "Some trivial cleanups for shmem" from Baolin Wang does as
   it claims.

 - The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
   Alistair Popple regularizes the weird ZONE_DEVICE page refcount
   handling in DAX, permittig the removal of a number of special-case
   checks.

 - The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
   preparatoty refactoring and cleanup of the mremap() code.

 - The series "mm: MM owner tracking for large folios (!hugetlb) +
   CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
   which we determine whether a large folio is known to be mapped
   exclusively into a single MM.

 - The series "mm/damon: add sysfs dirs for managing DAMOS filters based
   on handling layers" from SeongJae Park adds a couple of new sysfs
   directories to ease the management of DAMON/DAMOS filters.

 - The series "arch, mm: reduce code duplication in mem_init()" from
   Mike Rapoport consolidates many per-arch implementations of
   mem_init() into code generic code, where that is practical.

 - The series "mm/damon/sysfs: commit parameters online via
   damon_call()" from SeongJae Park continues the cleaning up of sysfs
   access to DAMON internal data.

 - The series "mm: page_ext: Introduce new iteration API" from Luiz
   Capitulino reworks the page_ext initialization to fix a boot-time
   crash which was observed with an unusual combination of compile and
   cmdline options.

 - The series "Buddy allocator like (or non-uniform) folio split" from
   Zi Yan reworks the code to split a folio into smaller folios. The
   main benefit is lessened memory consumption: fewer post-split folios
   are generated.

 - The series "Minimize xa_node allocation during xarry split" from Zi
   Yan reduces the number of xarray xa_nodes which are generated during
   an xarray split.

 - The series "drivers/base/memory: Two cleanups" from Gavin Shan
   performs some maintenance work on the drivers/base/memory code.

 - The series "Add tracepoints for lowmem reserves, watermarks and
   totalreserve_pages" from Martin Liu adds some more tracepoints to the
   page allocator code.

 - The series "mm/madvise: cleanup requests validations and
   classifications" from SeongJae Park cleans up some warts which
   SeongJae observed during his earlier madvise work.

 - The series "mm/hwpoison: Fix regressions in memory failure handling"
   from Shuai Xue addresses two quite serious regressions which Shuai
   has observed in the memory-failure implementation.

 - The series "mm: reliable huge page allocator" from Johannes Weiner
   makes huge page allocations cheaper and more reliable by reducing
   fragmentation.

 - The series "Minor memcg cleanups &amp; prep for memdescs" from Matthew
   Wilcox is preparatory work for the future implementation of memdescs.

 - The series "track memory used by balloon drivers" from Nico Pache
   introduces a way to track memory used by our various balloon drivers.

 - The series "mm/damon: introduce DAMOS filter type for active pages"
   from Nhat Pham permits users to filter for active/inactive pages,
   separately for file and anon pages.

 - The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
   separates the proactive reclaim statistics from the direct reclaim
   statistics.

 - The series "mm/vmscan: don't try to reclaim hwpoison folio" from
   Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
   code.

* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
  mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
  x86/mm: restore early initialization of high_memory for 32-bits
  mm/vmscan: don't try to reclaim hwpoison folio
  mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
  cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
  mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
  selftests/mm: speed up split_huge_page_test
  selftests/mm: uffd-unit-tests support for hugepages &gt; 2M
  docs/mm/damon/design: document active DAMOS filter type
  mm/damon: implement a new DAMOS filter type for active pages
  fs/dax: don't disassociate zero page entries
  MM documentation: add "Unaccepted" meminfo entry
  selftests/mm: add commentary about 9pfs bugs
  fork: use __vmalloc_node() for stack allocation
  docs/mm: Physical Memory: Populate the "Zones" section
  xen: balloon: update the NR_BALLOON_PAGES state
  hv_balloon: update the NR_BALLOON_PAGES state
  balloon_compaction: update the NR_BALLOON_PAGES state
  meminfo: add a per node counter for balloon drivers
  mm: remove references to folio in __memcg_kmem_uncharge_page()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>fuse: remove unneeded atomic set in uring creation</title>
<updated>2025-03-31T12:59:27+00:00</updated>
<author>
<name>Joanne Koong</name>
<email>joannelkoong@gmail.com</email>
</author>
<published>2025-03-18T00:41:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2d066800a4276340a97acc75c148892eb6f8781a'/>
<id>2d066800a4276340a97acc75c148892eb6f8781a</id>
<content type='text'>
When the ring is allocated, it is kzalloc-ed. ring-&gt;queue_refs will
already be initialized to 0 by default. It does not need to be
atomically set to 0.

Signed-off-by: Joanne Koong &lt;joannelkoong@gmail.com&gt;
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When the ring is allocated, it is kzalloc-ed. ring-&gt;queue_refs will
already be initialized to 0 by default. It does not need to be
atomically set to 0.

Signed-off-by: Joanne Koong &lt;joannelkoong@gmail.com&gt;
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fuse: fix uring race condition for null dereference of fc</title>
<updated>2025-03-31T12:59:27+00:00</updated>
<author>
<name>Joanne Koong</name>
<email>joannelkoong@gmail.com</email>
</author>
<published>2025-03-18T00:30:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1dfe2a220e9cd85861a853b00d8620222b960c1f'/>
<id>1dfe2a220e9cd85861a853b00d8620222b960c1f</id>
<content type='text'>
There is a race condition leading to a kernel crash from a null
dereference when attemping to access fc-&gt;lock in
fuse_uring_create_queue(). fc may be NULL in the case where another
thread is creating the uring in fuse_uring_create() and has set
fc-&gt;ring but has not yet set ring-&gt;fc when fuse_uring_create_queue()
reads ring-&gt;fc. There is another race condition as well where in
fuse_uring_register(), ring-&gt;nr_queues may still be 0 and not yet set
to the new value when we compare qid against it.

This fix sets fc-&gt;ring only after ring-&gt;fc and ring-&gt;nr_queues have been
set, which guarantees now that ring-&gt;fc is a proper pointer when any
queues are created and ring-&gt;nr_queues reflects the right number of
queues if ring is not NULL. We must use smp_store_release() and
smp_load_acquire() semantics to ensure the ordering will remain correct
where fc-&gt;ring is assigned only after ring-&gt;fc and ring-&gt;nr_queues have
been assigned.

Signed-off-by: Joanne Koong &lt;joannelkoong@gmail.com&gt;
Fixes: 24fe962c86f5 ("fuse: {io-uring} Handle SQEs - register commands")
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is a race condition leading to a kernel crash from a null
dereference when attemping to access fc-&gt;lock in
fuse_uring_create_queue(). fc may be NULL in the case where another
thread is creating the uring in fuse_uring_create() and has set
fc-&gt;ring but has not yet set ring-&gt;fc when fuse_uring_create_queue()
reads ring-&gt;fc. There is another race condition as well where in
fuse_uring_register(), ring-&gt;nr_queues may still be 0 and not yet set
to the new value when we compare qid against it.

This fix sets fc-&gt;ring only after ring-&gt;fc and ring-&gt;nr_queues have been
set, which guarantees now that ring-&gt;fc is a proper pointer when any
queues are created and ring-&gt;nr_queues reflects the right number of
queues if ring is not NULL. We must use smp_store_release() and
smp_load_acquire() semantics to ensure the ordering will remain correct
where fc-&gt;ring is assigned only after ring-&gt;fc and ring-&gt;nr_queues have
been assigned.

Signed-off-by: Joanne Koong &lt;joannelkoong@gmail.com&gt;
Fixes: 24fe962c86f5 ("fuse: {io-uring} Handle SQEs - register commands")
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fuse: Increase FUSE_NAME_MAX to PATH_MAX</title>
<updated>2025-03-31T12:59:27+00:00</updated>
<author>
<name>Bernd Schubert</name>
<email>bschubert@ddn.com</email>
</author>
<published>2024-12-16T21:14:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=27992ef80770d61a57f6c3a551735b08cefdffa3'/>
<id>27992ef80770d61a57f6c3a551735b08cefdffa3</id>
<content type='text'>
Our file system has a translation capability for S3-to-posix.
The current value of 1kiB is enough to cover S3 keys, but
does not allow encoding of %xx escape characters.
The limit is increased to (PATH_MAX - 1), as we need
3 x 1024 and that is close to PATH_MAX (4kB) already.
-1 is used as the terminating null is not included in the
length calculation.

Testing large file names was hard with libfuse/example file systems,
so I created a new memfs that does not have a 255 file name length
limitation.
https://github.com/libfuse/libfuse/pull/1077

The connection is initialized with FUSE_NAME_LOW_MAX, which
is set to the previous value of FUSE_NAME_MAX of 1024. With
FUSE_MIN_READ_BUFFER of 8192 that is enough for two file names
+ fuse headers.
When FUSE_INIT reply sets max_pages to a value &gt; 1 we know
that fuse daemon supports request buffers of at least 2 pages
(+ header) and can therefore hold 2 x PATH_MAX file names - operations
like rename or link that need two file names are no issue then.

Signed-off-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Our file system has a translation capability for S3-to-posix.
The current value of 1kiB is enough to cover S3 keys, but
does not allow encoding of %xx escape characters.
The limit is increased to (PATH_MAX - 1), as we need
3 x 1024 and that is close to PATH_MAX (4kB) already.
-1 is used as the terminating null is not included in the
length calculation.

Testing large file names was hard with libfuse/example file systems,
so I created a new memfs that does not have a 255 file name length
limitation.
https://github.com/libfuse/libfuse/pull/1077

The connection is initialized with FUSE_NAME_LOW_MAX, which
is set to the previous value of FUSE_NAME_MAX of 1024. With
FUSE_MIN_READ_BUFFER of 8192 that is enough for two file names
+ fuse headers.
When FUSE_INIT reply sets max_pages to a value &gt; 1 we know
that fuse daemon supports request buffers of at least 2 pages
(+ header) and can therefore hold 2 x PATH_MAX file names - operations
like rename or link that need two file names are no issue then.

Signed-off-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fuse: Allocate only namelen buf memory in fuse_notify_</title>
<updated>2025-03-31T12:59:27+00:00</updated>
<author>
<name>Bernd Schubert</name>
<email>bschubert@ddn.com</email>
</author>
<published>2024-12-16T21:14:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2412085da370836945c2daa61c5cee38dd979e0d'/>
<id>2412085da370836945c2daa61c5cee38dd979e0d</id>
<content type='text'>
fuse_notify_inval_entry and fuse_notify_delete were using fixed allocations
of FUSE_NAME_MAX to hold the file name. Often that large buffers are not
needed as file names might be smaller, so this uses the actual file name
size to do the allocation.

Signed-off-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Reviewed-by: Jingbo Xu &lt;jefflexu@linux.alibaba.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
fuse_notify_inval_entry and fuse_notify_delete were using fixed allocations
of FUSE_NAME_MAX to hold the file name. Often that large buffers are not
needed as file names might be smaller, so this uses the actual file name
size to do the allocation.

Signed-off-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Reviewed-by: Jingbo Xu &lt;jefflexu@linux.alibaba.com&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fuse: add default_request_timeout and max_request_timeout sysctls</title>
<updated>2025-03-31T12:59:27+00:00</updated>
<author>
<name>Joanne Koong</name>
<email>joannelkoong@gmail.com</email>
</author>
<published>2025-01-22T21:55:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9b17cb59a7db983a967c3658fe9a2f250f588bbd'/>
<id>9b17cb59a7db983a967c3658fe9a2f250f588bbd</id>
<content type='text'>
Introduce two new sysctls, "default_request_timeout" and
"max_request_timeout". These control how long (in seconds) a server can
take to reply to a request. If the server does not reply by the timeout,
then the connection will be aborted. The upper bound on these sysctl
values is 65535.

"default_request_timeout" sets the default timeout if no timeout is
specified by the fuse server on mount. 0 (default) indicates no default
timeout should be enforced. If the server did specify a timeout, then
default_request_timeout will be ignored.

"max_request_timeout" sets the max amount of time the server may take to
reply to a request. 0 (default) indicates no maximum timeout. If
max_request_timeout is set and the fuse server attempts to set a
timeout greater than max_request_timeout, the system will use
max_request_timeout as the timeout. Similarly, if default_request_timeout
is greater than max_request_timeout, the system will use
max_request_timeout as the timeout. If the server does not request a
timeout and default_request_timeout is set to 0 but max_request_timeout
is set, then the timeout will be max_request_timeout.

Please note that these timeouts are not 100% precise. The request may
take roughly an extra FUSE_TIMEOUT_TIMER_FREQ seconds beyond the set max
timeout due to how it's internally implemented.

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 0

$ echo 65536 | sudo tee /proc/sys/fs/fuse/default_request_timeout
tee: /proc/sys/fs/fuse/default_request_timeout: Invalid argument

$ echo 65535 | sudo tee /proc/sys/fs/fuse/default_request_timeout
65535

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 65535

$ echo 0 | sudo tee /proc/sys/fs/fuse/default_request_timeout
0

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 0

[Luis Henriques: Limit the timeout to the range [FUSE_TIMEOUT_TIMER_FREQ,
fuse_max_req_timeout]]

Signed-off-by: Joanne Koong &lt;joannelkoong@gmail.com&gt;
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Reviewed-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Reviewed-by: Sergey Senozhatsky &lt;senozhatsky@chromium.org&gt;
Reviewed-by: Luis Henriques &lt;luis@igalia.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Introduce two new sysctls, "default_request_timeout" and
"max_request_timeout". These control how long (in seconds) a server can
take to reply to a request. If the server does not reply by the timeout,
then the connection will be aborted. The upper bound on these sysctl
values is 65535.

"default_request_timeout" sets the default timeout if no timeout is
specified by the fuse server on mount. 0 (default) indicates no default
timeout should be enforced. If the server did specify a timeout, then
default_request_timeout will be ignored.

"max_request_timeout" sets the max amount of time the server may take to
reply to a request. 0 (default) indicates no maximum timeout. If
max_request_timeout is set and the fuse server attempts to set a
timeout greater than max_request_timeout, the system will use
max_request_timeout as the timeout. Similarly, if default_request_timeout
is greater than max_request_timeout, the system will use
max_request_timeout as the timeout. If the server does not request a
timeout and default_request_timeout is set to 0 but max_request_timeout
is set, then the timeout will be max_request_timeout.

Please note that these timeouts are not 100% precise. The request may
take roughly an extra FUSE_TIMEOUT_TIMER_FREQ seconds beyond the set max
timeout due to how it's internally implemented.

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 0

$ echo 65536 | sudo tee /proc/sys/fs/fuse/default_request_timeout
tee: /proc/sys/fs/fuse/default_request_timeout: Invalid argument

$ echo 65535 | sudo tee /proc/sys/fs/fuse/default_request_timeout
65535

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 65535

$ echo 0 | sudo tee /proc/sys/fs/fuse/default_request_timeout
0

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 0

[Luis Henriques: Limit the timeout to the range [FUSE_TIMEOUT_TIMER_FREQ,
fuse_max_req_timeout]]

Signed-off-by: Joanne Koong &lt;joannelkoong@gmail.com&gt;
Reviewed-by: Bernd Schubert &lt;bschubert@ddn.com&gt;
Reviewed-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Reviewed-by: Sergey Senozhatsky &lt;senozhatsky@chromium.org&gt;
Reviewed-by: Luis Henriques &lt;luis@igalia.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
