Re: [PATCH v1 00/11] Put struct nfsd4_copy on a diet

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On 7/27/22 11:48 AM, Olga Kornievskaia wrote:
On Wed, Jul 27, 2022 at 2:21 PM Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
On Wed, Jul 27, 2022 at 2:04 PM Chuck Lever III <chuck.lever@xxxxxxxxxx> wrote:


On Jul 27, 2022, at 1:52 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:

After applying Dai's patch I got further... I hit the next panic
(below)... before that it ran into a failure for "inter01" failed with
ECOMM. On hte trace, after the COPY is places the server returns
ESTALE in CB_OFFLOAD, then close is failed with BAD_SESSION (just
basically something really wrong happened on the server)... After
failing a new more tests in the similar fashion.. On cleanup the oops
happens.
What test should I run to reproduce this?
I'm running "./nfstest_ssc". It ran thru all with "inter15" being
last, then started "cleanup" and that's what panic-ed the server.

It's been a while since I tested ssc... so i'll undo all the patched
and re-run the tests to make sure that before code worked.
It looks like the code got broken before this patch set. The ESTALE in
CB_OFFLOAD leading to ECOM error happens without your patches. And
then the kernel panic. I'll do my best to git bisect where the problem
occurred first.

I think this this is what lead to the list_del corruption problem:

Jul 27 12:14:23 nfsvmd07 kernel: ==================================================================
Jul 27 12:14:23 nfsvmd07 kernel: BUG: KASAN: use-after-free in __list_del_entry_valid+0x16e/0x180
Jul 27 12:14:23 nfsvmd07 kernel: Read of size 8 at addr ffff8881189c8230 by task kworker/u2:1/23
Jul 27 12:14:23 nfsvmd07 kernel:
Jul 27 12:14:23 nfsvmd07 kernel: CPU: 0 PID: 23 Comm: kworker/u2:1 Not tainted 5.19.0-rc7+ #1
Jul 27 12:14:23 nfsvmd07 kernel: Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
Jul 27 12:14:23 nfsvmd07 kernel: Workqueue: nfsd4 laundromat_main [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: Call Trace:
Jul 27 12:14:23 nfsvmd07 kernel: <TASK>
Jul 27 12:14:23 nfsvmd07 kernel: dump_stack_lvl+0x57/0x7d
Jul 27 12:14:23 nfsvmd07 kernel: print_report.cold+0xf8/0x654
Jul 27 12:14:23 nfsvmd07 kernel: ? __list_del_entry_valid+0x16e/0x180
Jul 27 12:14:23 nfsvmd07 kernel: kasan_report+0x8a/0x190
Jul 27 12:14:23 nfsvmd07 kernel: ? pm_suspend.cold+0x4e2/0x4e2
Jul 27 12:14:23 nfsvmd07 kernel: ? __list_del_entry_valid+0x16e/0x180
Jul 27 12:14:23 nfsvmd07 kernel: __list_del_entry_valid+0x16e/0x180
Jul 27 12:14:23 nfsvmd07 kernel: __list_del_entry+0xa/0xb0 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: _free_cpntf_state_locked+0x75/0x170 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: laundromat_main.cold+0x23/0x28 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: ? release_lock_stateid+0x70/0x70 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: ? rcu_read_lock_sched_held+0x81/0xb0
Jul 27 12:14:23 nfsvmd07 kernel: ? rcu_read_lock_bh_held+0x90/0x90
Jul 27 12:14:23 nfsvmd07 kernel: process_one_work+0x7cc/0x1350
Jul 27 12:14:23 nfsvmd07 kernel: ? lockdep_hardirqs_on_prepare+0x410/0x410
Jul 27 12:14:23 nfsvmd07 kernel: ? queue_delayed_work_on+0x90/0x90
Jul 27 12:14:23 nfsvmd07 kernel: ? rwlock_bug.part.0+0x90/0x90
Jul 27 12:14:23 nfsvmd07 kernel: worker_thread+0x55d/0xe80
Jul 27 12:14:23 nfsvmd07 kernel: ? process_one_work+0x1350/0x1350
Jul 27 12:14:23 nfsvmd07 kernel: kthread+0x29e/0x340
Jul 27 12:14:23 nfsvmd07 kernel: ? kthread_complete_and_exit+0x20/0x20
Jul 27 12:14:23 nfsvmd07 kernel: ret_from_fork+0x1f/0x30
Jul 27 12:14:23 nfsvmd07 kernel: </TASK>
Jul 27 12:14:23 nfsvmd07 kernel:
Jul 27 12:14:23 nfsvmd07 kernel: Allocated by task 4051:
Jul 27 12:14:23 nfsvmd07 kernel: kasan_save_stack+0x1e/0x40
Jul 27 12:14:23 nfsvmd07 kernel: __kasan_slab_alloc+0x64/0x80
Jul 27 12:14:23 nfsvmd07 kernel: kmem_cache_alloc+0xeb/0x2c0
Jul 27 12:14:23 nfsvmd07 kernel: nfs4_alloc_stid+0x29/0x430 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd4_lock+0x1e9e/0x3cb0 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd4_proc_compound+0xd75/0x26c0 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd_dispatch+0x4e8/0xc00 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: svc_process_common+0xb51/0x1af0 [sunrpc]
Jul 27 12:14:23 nfsvmd07 kernel: svc_process+0x361/0x4f0 [sunrpc]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd+0x2d6/0x570 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: kthread+0x29e/0x340
Jul 27 12:14:23 nfsvmd07 kernel: ret_from_fork+0x1f/0x30
Jul 27 12:14:23 nfsvmd07 kernel:
Jul 27 12:14:23 nfsvmd07 kernel: Freed by task 4051:
Jul 27 12:14:23 nfsvmd07 kernel: kasan_save_stack+0x1e/0x40
Jul 27 12:14:23 nfsvmd07 kernel: kasan_set_track+0x21/0x30
Jul 27 12:14:23 nfsvmd07 kernel: kasan_set_free_info+0x20/0x30
Jul 27 12:14:23 nfsvmd07 kernel: __kasan_slab_free+0xf0/0x160
Jul 27 12:14:23 nfsvmd07 kernel: kmem_cache_free.part.0+0x7f/0x1c0
Jul 27 12:14:23 nfsvmd07 kernel: free_ol_stateid_reaplist+0x12b/0x200 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd4_close+0x58e/0xe10 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd4_proc_compound+0xd75/0x26c0 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd_dispatch+0x4e8/0xc00 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: svc_process_common+0xb51/0x1af0 [sunrpc]
Jul 27 12:14:23 nfsvmd07 kernel: svc_process+0x361/0x4f0 [sunrpc]
Jul 27 12:14:23 nfsvmd07 kernel: nfsd+0x2d6/0x570 [nfsd]
Jul 27 12:14:23 nfsvmd07 kernel: kthread+0x29e/0x340
Jul 27 12:14:23 nfsvmd07 kernel: ret_from_fork+0x1f/0x30
Jul 27 12:14:23 nfsvmd07 kernel:
Jul 27 12:14:23 nfsvmd07 kernel: The buggy address belongs to the object at ffff8881189c8228#012 which belongs to the cache nfsd4_stateids of size 360
Jul 27 12:14:23 nfsvmd07 kernel: The buggy address is located 8 bytes inside of#012 360-byte region [ffff8881189c8228, ffff8881189c8390)
Jul 27 12:14:23 nfsvmd07 kernel:
Jul 27 12:14:23 nfsvmd07 kernel: The buggy address belongs to the physical page:
Jul 27 12:14:23 nfsvmd07 kernel: page:000000009faa88de refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1189c8
Jul 27 12:14:23 nfsvmd07 kernel: flags: 0x8000000000000200(slab|zone=2)
Jul 27 12:14:23 nfsvmd07 kernel: raw: 8000000000000200 ffff8881008a0950 ffffea000399e380 ffff888108fd9d00
Jul 27 12:14:23 nfsvmd07 kernel: raw: 0000000000000000 ffff8881189c8080 0000000100000009
Jul 27 12:14:23 nfsvmd07 kernel: page dumped because: kasan: bad access detected
Jul 27 12:14:23 nfsvmd07 kernel:
Jul 27 12:14:23 nfsvmd07 kernel: Memory state around the buggy address:
Jul 27 12:14:23 nfsvmd07 kernel: ffff8881189c8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Jul 27 12:14:23 nfsvmd07 kernel: ffff8881189c8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
Jul 27 12:14:23 nfsvmd07 kernel: >ffff8881189c8200: fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb
Jul 27 12:14:23 nfsvmd07 kernel:                                     ^
Jul 27 12:14:23 nfsvmd07 kernel: ffff8881189c8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Jul 27 12:14:23 nfsvmd07 kernel: ffff8881189c8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Jul 27 12:14:23 nfsvmd07 kernel: ==================================================================

I think nfs4_free_ol_stateid needs to also removing the
nfs4_cpntf_state from the s2s_cp_stateids list, still
validating.

-Dai


[  842.455939] list_del corruption. prev->next should be
ffff9aaa8b5f0c78, but was ffff9aaab2713508. (prev=ffff9aaab2713510)
[  842.460118] ------------[ cut here ]------------
[  842.461599] kernel BUG at lib/list_debug.c:53!
[  842.462962] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[  842.464587] CPU: 1 PID: 500 Comm: kworker/u256:28 Not tainted 5.18.0 #70
[  842.466656] Hardware name: VMware, Inc. VMware Virtual
Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
[  842.470309] Workqueue: nfsd4 laundromat_main [nfsd]
[  842.471898] RIP: 0010:__list_del_entry_valid.cold.3+0x37/0x4a
[  842.473792] Code: e8 02 d8 fe ff 0f 0b 48 c7 c7 c0 bb b6 b0 e8 f4
d7 fe ff 0f 0b 48 89 d1 48 89 f2 48 89 fe 48 c7 c7 70 bb b6 b0 e8 dd
d7 fe ff <0f> 0b 48 89 fe 48 c7 c7 38 bb b6 b0 e8 cc d7 fe ff 0f 0b 48
89 ee
[  842.479607] RSP: 0018:ffffa996c0ca7de8 EFLAGS: 00010246
[  842.481828] RAX: 000000000000006d RBX: ffff9aaa8b5f0c60 RCX: 0000000000000002
[  842.484769] RDX: 0000000000000000 RSI: ffffffffb0b64d55 RDI: 00000000ffffffff
[  842.487252] RBP: ffff9aaab9b62000 R08: 0000000000000000 R09: c0000000ffff7fff
[  842.489939] R10: 0000000000000001 R11: ffffa996c0ca7c00 R12: ffffa996c0ca7e50
[  842.492215] R13: ffff9aaab9b621b0 R14: fffffffffffffd12 R15: ffff9aaab9b62198
[  842.494406] FS:  0000000000000000(0000) GS:ffff9aaafbe40000(0000)
knlGS:0000000000000000
[  842.496939] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  842.498759] CR2: 000055a8b4e96010 CR3: 0000000003a18001 CR4: 00000000001706e0
[  842.500957] Call Trace:
[  842.501740]  <TASK>
[  842.502479]  _free_cpntf_state_locked+0x36/0x90 [nfsd]
[  842.504157]  laundromat_main+0x59e/0x8b0 [nfsd]
[  842.505594]  ? finish_task_switch+0xbd/0x2a0
[  842.507247]  process_one_work+0x1c8/0x390
[  842.508538]  worker_thread+0x30/0x360
[  842.509670]  ? process_one_work+0x390/0x390
[  842.510957]  kthread+0xe8/0x110
[  842.511938]  ? kthread_complete_and_exit+0x20/0x20
[  842.513422]  ret_from_fork+0x22/0x30
[  842.514533]  </TASK>
[  842.515219] Modules linked in: rdma_ucm ib_uverbs rpcrdma rdma_cm
iw_cm ib_cm ib_core nfsd nfs_acl lockd grace ext4 mbcache jbd2 fuse
xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT
nf_reject_ipv4 nft_compat nf_tables nfnetlink tun bridge stp llc bnep
vmw_vsock_vmci_transport vsock intel_rapl_msr snd_seq_midi
snd_seq_midi_event intel_rapl_common crct10dif_pclmul crc32_pclmul
vmw_balloon ghash_clmulni_intel pcspkr joydev btusb uvcvideo btrtl
btbcm btintel videobuf2_vmalloc videobuf2_memops snd_ens1371
videobuf2_v4l2 snd_ac97_codec ac97_bus videobuf2_common snd_seq
videodev snd_pcm bluetooth rfkill mc snd_timer snd_rawmidi
ecdh_generic snd_seq_device ecc snd soundcore vmw_vmci i2c_piix4
auth_rpcgss sunrpc ip_tables xfs libcrc32c sr_mod cdrom sg ata_generic
nvme nvme_core t10_pi crc32c_intel crc64_rocksoft serio_raw crc64
vmwgfx vmxnet3 drm_ttm_helper ata_piix ttm drm_kms_helper syscopyarea
sysfillrect sysimgblt fb_sys_fops ahci libahci drm libata
[  842.541753] ---[ end trace 0000000000000000 ]---
[  842.543403] RIP: 0010:__list_del_entry_valid.cold.3+0x37/0x4a
[  842.545170] Code: e8 02 d8 fe ff 0f 0b 48 c7 c7 c0 bb b6 b0 e8 f4
d7 fe ff 0f 0b 48 89 d1 48 89 f2 48 89 fe 48 c7 c7 70 bb b6 b0 e8 dd
d7 fe ff <0f> 0b 48 89 fe 48 c7 c7 38 bb b6 b0 e8 cc d7 fe ff 0f 0b 48
89 ee
[  842.551346] RSP: 0018:ffffa996c0ca7de8 EFLAGS: 00010246
[  842.552999] RAX: 000000000000006d RBX: ffff9aaa8b5f0c60 RCX: 0000000000000002
[  842.555151] RDX: 0000000000000000 RSI: ffffffffb0b64d55 RDI: 00000000ffffffff
[  842.557503] RBP: ffff9aaab9b62000 R08: 0000000000000000 R09: c0000000ffff7fff
[  842.559694] R10: 0000000000000001 R11: ffffa996c0ca7c00 R12: ffffa996c0ca7e50
[  842.561956] R13: ffff9aaab9b621b0 R14: fffffffffffffd12 R15: ffff9aaab9b62198
[  842.564300] FS:  0000000000000000(0000) GS:ffff9aaafbe40000(0000)
knlGS:0000000000000000
[  842.567357] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  842.569273] CR2: 000055a8b4e96010 CR3: 0000000003a18001 CR4: 00000000001706e0
[  842.571598] Kernel panic - not syncing: Fatal exception
[  842.573674] Kernel Offset: 0x2e800000 from 0xffffffff81000000
(relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 1101.134589] ---[ end Kernel panic - not syncing: Fatal exception ]---

On Wed, Jul 27, 2022 at 1:15 PM Chuck Lever III <chuck.lever@xxxxxxxxxx> wrote:


On Jul 27, 2022, at 12:18 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:

Hi Chuck,
Sorry for the delay, I was traveling.

To make it compile I did:
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 7196bcafdd86..f6deffc921d0 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1536,7 +1536,7 @@ nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
       if (status)
               goto out;

-       status = nfsd4_interssc_connect(&copy->cp_src, rqstp, mount);
+       status = nfsd4_interssc_connect(copy->cp_src, rqstp, mount);
       if (status)
               goto out;
Yes, same bug was reported by the day-0 kbot. v1 was kind of an RFC,
as I hadn't fully tested it. Sorry for mislabeling it.

I will post a v2 of this series with this fixed and with Dai's
fix for nfsd4_decode_copy(). Stand by.


But when I tried to run the nfstest_ssc. The first test (intra01) made
the server oops:

[ 9569.551100] CPU: 0 PID: 2861 Comm: nfsd Not tainted 5.19.0-rc6+ #73
[ 9569.552385] Hardware name: VMware, Inc. VMware Virtual
Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
[ 9569.555043] RIP: 0010:nfsd4_copy+0x28b/0x4e0 [nfsd]
[ 9569.556662] Code: 24 38 49 89 94 24 10 01 00 00 49 8b 56 08 48 8d
79 08 49 89 94 24 18 01 00 00 49 8b 56 10 48 83 e7 f8 49 89 94 24 20
01 00 00 <48> 8b 06 48 89 01 48 8b 86 04 04 00 00 48 89 81 04 04 00 00
48 29
[ 9569.561792] RSP: 0018:ffffb092c0c97dd0 EFLAGS: 00010282
[ 9569.563112] RAX: ffff99b5465c2460 RBX: ffff99b5a68828e0 RCX: ffff99b5853b6000
[ 9569.565196] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff99b5853b6008
[ 9569.567140] RBP: ffffb092c0c97e10 R08: ffffffffc0bf3c24 R09: 0000000000000228
[ 9569.568929] R10: ffff99b54b0e9268 R11: ffff99b564326998 R12: ffff99b5543dfc00
[ 9569.570477] R13: ffff99b5a6882950 R14: ffff99b5a68829f0 R15: ffff99b546edc000
[ 9569.572052] FS:  0000000000000000(0000) GS:ffff99b5bbe00000(0000)
knlGS:0000000000000000
[ 9569.573926] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9569.575281] CR2: 0000000000000000 CR3: 0000000076c36002 CR4: 00000000001706f0
[ 9569.577586] Call Trace:
[ 9569.578220]  <TASK>
[ 9569.578770]  ? nfsd4_proc_compound+0x3d2/0x730 [nfsd]
[ 9569.579945]  nfsd4_proc_compound+0x3d2/0x730 [nfsd]
[ 9569.581055]  nfsd_dispatch+0x146/0x270 [nfsd]
[ 9569.581987]  svc_process_common+0x365/0x5c0 [sunrpc]
[ 9569.583122]  ? nfsd_svc+0x350/0x350 [nfsd]
[ 9569.583986]  ? nfsd_shutdown_threads+0x90/0x90 [nfsd]
[ 9569.585129]  svc_process+0xb7/0xf0 [sunrpc]
[ 9569.586169]  nfsd+0xd5/0x190 [nfsd]
[ 9569.587170]  kthread+0xe8/0x110
[ 9569.587898]  ? kthread_complete_and_exit+0x20/0x20
[ 9569.588934]  ret_from_fork+0x22/0x30
[ 9569.589759]  </TASK>
[ 9569.590224] Modules linked in: rdma_ucm ib_uverbs rpcrdma rdma_cm
iw_cm ib_cm ib_core nfsd nfs_acl lockd grace ext4 mbcache jbd2 fuse
xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT
nf_reject_ipv4 nft_compat nf_tables nfnetlink tun bridge stp llc bnep
vmw_vsock_vmci_transport vsock snd_seq_midi snd_seq_midi_event
intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul
vmw_balloon ghash_clmulni_intel joydev pcspkr btusb btrtl btbcm
btintel snd_ens1371 uvcvideo snd_ac97_codec videobuf2_vmalloc ac97_bus
videobuf2_memops videobuf2_v4l2 videobuf2_common snd_seq snd_pcm
videodev bluetooth mc rfkill ecdh_generic ecc snd_timer snd_rawmidi
snd_seq_device snd vmw_vmci soundcore i2c_piix4 auth_rpcgss sunrpc
ip_tables xfs libcrc32c sr_mod cdrom sg ata_generic crc32c_intel
ata_piix nvme ahci libahci nvme_core t10_pi crc64_rocksoft serio_raw
crc64 vmwgfx drm_ttm_helper ttm drm_kms_helper syscopyarea sysfillrect
sysimgblt fb_sys_fops vmxnet3 drm libata
[ 9569.610612] CR2: 0000000000000000
[ 9569.611375] ---[ end trace 0000000000000000 ]---
[ 9569.612424] RIP: 0010:nfsd4_copy+0x28b/0x4e0 [nfsd]
[ 9569.613472] Code: 24 38 49 89 94 24 10 01 00 00 49 8b 56 08 48 8d
79 08 49 89 94 24 18 01 00 00 49 8b 56 10 48 83 e7 f8 49 89 94 24 20
01 00 00 <48> 8b 06 48 89 01 48 8b 86 04 04 00 00 48 89 81 04 04 00 00
48 29
[ 9569.617410] RSP: 0018:ffffb092c0c97dd0 EFLAGS: 00010282
[ 9569.618487] RAX: ffff99b5465c2460 RBX: ffff99b5a68828e0 RCX: ffff99b5853b6000
[ 9569.620097] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff99b5853b6008
[ 9569.621710] RBP: ffffb092c0c97e10 R08: ffffffffc0bf3c24 R09: 0000000000000228
[ 9569.623398] R10: ffff99b54b0e9268 R11: ffff99b564326998 R12: ffff99b5543dfc00
[ 9569.625019] R13: ffff99b5a6882950 R14: ffff99b5a68829f0 R15: ffff99b546edc000
[ 9569.627456] FS:  0000000000000000(0000) GS:ffff99b5bbe00000(0000)
knlGS:0000000000000000
[ 9569.629249] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9569.630433] CR2: 0000000000000000 CR3: 0000000076c36002 CR4: 00000000001706f0
[ 9569.632043] Kernel panic - not syncing: Fatal exception



On Tue, Jul 26, 2022 at 3:45 PM Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
Chuck,

Are there pre-reqs for this series? I had tried to apply the patches
on top of 5-19-rc6 but I get the following compile error:

fs/nfsd/nfs4proc.c: In function ‘nfsd4_setup_inter_ssc’:
fs/nfsd/nfs4proc.c:1539:34: error: passing argument 1 of
‘nfsd4_interssc_connect’ from incompatible pointer type
[-Werror=incompatible-pointer-types]
status = nfsd4_interssc_connect(&copy->cp_src, rqstp, mount);
                                 ^~~~~~~~~~~~~
fs/nfsd/nfs4proc.c:1414:43: note: expected ‘struct nl4_server *’ but
argument is of type ‘struct nl4_server **’
nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
                       ~~~~~~~~~~~~~~~~~~~^~~
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:249: fs/nfsd/nfs4proc.o] Error 1
make[1]: *** [scripts/Makefile.build:466: fs/nfsd] Error 2
make: *** [Makefile:1843: fs] Error 2

On Fri, Jul 22, 2022 at 4:36 PM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
While testing NFSD for-next, I noticed svc_generic_init_request()
was an unexpected hot spot on NFSv4 workloads. Drilling into the
perf report, it shows that the hot path in there is:

1208         memset(rqstp->rq_argp, 0, procp->pc_argsize);
1209         memset(rqstp->rq_resp, 0, procp->pc_ressize);

For an NFSv4 COMPOUND,

       procp->pc_argsize = sizeof(nfsd4_compoundargs),

struct nfsd4_compoundargs on my system is more than 17KB! This is
due to the size of the iops field:

       struct nfsd4_op                 iops[8];

Each struct nfsd4_op contains a union of the arguments for each
NFSv4 operation. Each argument is typically less than 128 bytes
except that struct nfsd4_copy and struct nfsd4_copy_notify are both
larger than 2KB each.

I'm not yet totally convinced this series never orphans memory, but
it does reduce the size of nfsd4_compoundargs to just over 4KB. This
is still due to struct nfsd4_copy being almost 500 bytes. I don't
see more low-hanging fruit there, though.

---

Chuck Lever (11):
     NFSD: Shrink size of struct nfsd4_copy_notify
     NFSD: Shrink size of struct nfsd4_copy
     NFSD: Reorder the fields in struct nfsd4_op
     NFSD: Make nfs4_put_copy() static
     NFSD: Make boolean fields in struct nfsd4_copy into atomic bit flags
     NFSD: Refactor nfsd4_cleanup_inter_ssc() (1/2)
     NFSD: Refactor nfsd4_cleanup_inter_ssc() (2/2)
     NFSD: Refactor nfsd4_do_copy()
     NFSD: Remove kmalloc from nfsd4_do_async_copy()
     NFSD: Add nfsd4_send_cb_offload()
     NFSD: Move copy offload callback arguments into a separate structure


fs/nfsd/nfs4callback.c |  37 +++++----
fs/nfsd/nfs4proc.c     | 165 +++++++++++++++++++++--------------------
fs/nfsd/nfs4xdr.c      |  30 +++++---
fs/nfsd/state.h        |   1 -
fs/nfsd/xdr4.h         |  54 ++++++++++----
5 files changed, 163 insertions(+), 124 deletions(-)

--
Chuck Lever

--
Chuck Lever



--
Chuck Lever






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