I did see the generic/241 failure again with current for-next
(unrelated to this patch though). Will try to repro it again - but
any ideas how to narrow it down or fix it would be helpful.
SECTION -- smb3
FSTYP -- cifs
PLATFORM -- Linux/x86_64 fedora29 6.12.0 #1 SMP PREEMPT_DYNAMIC Wed
Nov 27 01:02:07 UTC 2024
MKFS_OPTIONS -- //win16.vm.test/Scratch
generic/241 73s
Ran: generic/241
Passed all 1 tests
SECTION -- smb3
=========================
Ran: generic/241
Passed all 1 tests
Number of reconnects: 0
Test completed smb3 generic/241 at Wed Nov 27 06:38:47 AM UTC 2024
dmesg output during the test:
[Wed Nov 27 00:37:32 2024] CIFS: Attempting to mount //win16.vm.test/Share
[Wed Nov 27 00:37:32 2024] CIFS: VFS: generate_smb3signingkey: dumping
generated AES session keys
[Wed Nov 27 00:37:32 2024] CIFS: VFS: Session Id 45 00 00 08 00 c8 00 00
[Wed Nov 27 00:37:32 2024] CIFS: VFS: Cipher type 2
[Wed Nov 27 00:37:32 2024] CIFS: VFS: Session Key 00 bf ed c7 f1 95 0e
29 06 e8 82 87 b5 c8 72 06
[Wed Nov 27 00:37:32 2024] CIFS: VFS: Signing Key a4 0f 15 64 d2 69 02
2f 4e 78 60 7a fe 3e 31 4e
[Wed Nov 27 00:37:32 2024] CIFS: VFS: ServerIn Key a6 fd 04 f6 04 ea
0e 6e 60 c0 1b b1 ee 63 38 e9
[Wed Nov 27 00:37:32 2024] CIFS: VFS: ServerOut Key a6 e3 e3 22 8c c2
b0 6e b1 9d 40 ea d0 89 6d d8
[Wed Nov 27 00:37:32 2024] CIFS: Attempting to mount //win16.vm.test/Scratch
[Wed Nov 27 00:37:32 2024] CIFS: Attempting to mount //win16.vm.test/Scratch
[Wed Nov 27 00:37:32 2024] run fstests generic/241 at 2024-11-27 00:37:33
[Wed Nov 27 00:38:46 2024] ------------[ cut here ]------------
[Wed Nov 27 00:38:46 2024] BUG: Dentry
00000000318d67d4{i=11000000033f68,n=~dmtmp} still in use (1) [unmount
of cifs cifs]
[Wed Nov 27 00:38:46 2024] WARNING: CPU: 2 PID: 316177 at
fs/dcache.c:1546 umount_check+0xc3/0xf0
[Wed Nov 27 00:38:46 2024] Modules linked in: cifs ccm cmac nls_utf8
cifs_arc4 nls_ucs2_utils cifs_md4 rpcsec_gss_krb5 auth_rpcgss nfsv4
dns_resolver nfs lockd grace netfs nf_conntrack_netbios_ns
nf_conntrack_broadcast nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct
nft_chain_nat nf_tables ebtable_nat ebtable_broute ip6table_nat
ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat
nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw
iptable_security ip_set ebtable_filter ebtables ip6table_filter
ip6_tables iptable_filter ip_tables sunrpc kvm_intel kvm virtio_net
net_failover failover virtio_balloon loop fuse dm_multipath nfnetlink
zram xfs bochs drm_client_lib drm_shmem_helper drm_kms_helper
crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel drm
sha512_ssse3 sha256_ssse3 sha1_ssse3 floppy virtio_blk qemu_fw_cfg
virtio_console [last unloaded: cifs]
[Wed Nov 27 00:38:46 2024] CPU: 2 UID: 0 PID: 316177 Comm: umount Not
tainted 6.12.0 #1
[Wed Nov 27 00:38:46 2024] Hardware name: Red Hat KVM, BIOS
1.16.3-2.el9 04/01/2014
[Wed Nov 27 00:38:46 2024] RIP: 0010:umount_check+0xc3/0xf0
[Wed Nov 27 00:38:46 2024] Code: db 74 0d 48 8d 7b 40 e8 db df f5 ff
48 8b 53 40 41 55 4d 89 f1 45 89 e0 48 89 e9 48 89 ee 48 c7 c7 80 99
ba ad e8 2d 27 a2 ff <0f> 0b 58 31 c0 5b 5d 41 5c 41 5d 41 5e c3 cc cc
cc cc 41 83 fc 01
[Wed Nov 27 00:38:46 2024] RSP: 0018:ff1100012197fd20 EFLAGS: 00010282
[Wed Nov 27 00:38:46 2024] RAX: dffffc0000000000 RBX: ff1100010c574ce0
RCX: 0000000000000027
[Wed Nov 27 00:38:46 2024] RDX: 0000000000000027 RSI: 0000000000000004
RDI: ff110004cb131a48
[Wed Nov 27 00:38:46 2024] RBP: ff1100012c76bd60 R08: ffffffffac3fd2fe
R09: ffe21c0099626349
[Wed Nov 27 00:38:46 2024] R10: ff110004cb131a4b R11: 0000000000000001
R12: 0000000000000001
[Wed Nov 27 00:38:46 2024] R13: ff110001238b6668 R14: ffffffffc1d6e6c0
R15: ff1100012c76be18
[Wed Nov 27 00:38:46 2024] FS: 00007fddc1dcc800(0000)
GS:ff110004cb100000(0000) knlGS:0000000000000000
[Wed Nov 27 00:38:46 2024] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[Wed Nov 27 00:38:46 2024] CR2: 00007fc6440095d0 CR3: 0000000142146005
CR4: 0000000000373ef0
[Wed Nov 27 00:38:46 2024] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[Wed Nov 27 00:38:46 2024] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[Wed Nov 27 00:38:46 2024] Call Trace:
[Wed Nov 27 00:38:46 2024] <TASK>
[Wed Nov 27 00:38:46 2024] ? __warn+0xa9/0x220
[Wed Nov 27 00:38:46 2024] ? umount_check+0xc3/0xf0
[Wed Nov 27 00:38:46 2024] ? report_bug+0x1d4/0x1e0
[Wed Nov 27 00:38:46 2024] ? handle_bug+0x5b/0xa0
[Wed Nov 27 00:38:46 2024] ? exc_invalid_op+0x18/0x50
[Wed Nov 27 00:38:46 2024] ? asm_exc_invalid_op+0x1a/0x20
[Wed Nov 27 00:38:46 2024] ? irq_work_claim+0x1e/0x40
[Wed Nov 27 00:38:46 2024] ? umount_check+0xc3/0xf0
[Wed Nov 27 00:38:46 2024] ? __pfx_umount_check+0x10/0x10
[Wed Nov 27 00:38:46 2024] d_walk+0xf3/0x4e0
[Wed Nov 27 00:38:46 2024] ? d_walk+0x4b/0x4e0
[Wed Nov 27 00:38:46 2024] shrink_dcache_for_umount+0x6d/0x220
[Wed Nov 27 00:38:46 2024] generic_shutdown_super+0x4a/0x1c0
[Wed Nov 27 00:38:46 2024] kill_anon_super+0x22/0x40
[Wed Nov 27 00:38:46 2024] cifs_kill_sb+0x78/0x90 [cifs]
[Wed Nov 27 00:38:46 2024] deactivate_locked_super+0x69/0xf0
[Wed Nov 27 00:38:46 2024] cleanup_mnt+0x195/0x200
[Wed Nov 27 00:38:46 2024] task_work_run+0xec/0x150
[Wed Nov 27 00:38:46 2024] ? __pfx_task_work_run+0x10/0x10
[Wed Nov 27 00:38:46 2024] ? mark_held_locks+0x24/0x90
[Wed Nov 27 00:38:46 2024] syscall_exit_to_user_mode+0x269/0x2a0
[Wed Nov 27 00:38:46 2024] do_syscall_64+0x81/0x180
[Wed Nov 27 00:38:46 2024] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Wed Nov 27 00:38:46 2024] RIP: 0033:0x7fddc1ff43eb
[Wed Nov 27 00:38:46 2024] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f
1f 40 00 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa
b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15
f9 a9 0c 00 f7 d8
[Wed Nov 27 00:38:46 2024] RSP: 002b:00007ffe64be88d8 EFLAGS: 00000246
ORIG_RAX: 00000000000000a6
[Wed Nov 27 00:38:46 2024] RAX: 0000000000000000 RBX: 00005632106d4c20
RCX: 00007fddc1ff43eb
[Wed Nov 27 00:38:46 2024] RDX: 0000000000000000 RSI: 0000000000000000
RDI: 00005632106d9410
[Wed Nov 27 00:38:46 2024] RBP: 00007ffe64be89b0 R08: 00005632106d4010
R09: 0000000000000007
[Wed Nov 27 00:38:46 2024] R10: 0000000000000000 R11: 0000000000000246
R12: 00005632106d4d28
[Wed Nov 27 00:38:46 2024] R13: 0000000000000000 R14: 00005632106d9410
R15: 00005632106d5030
[Wed Nov 27 00:38:46 2024] </TASK>
[Wed Nov 27 00:38:46 2024] irq event stamp: 8317
[Wed Nov 27 00:38:46 2024] hardirqs last enabled at (8323):
[<ffffffffac230dce>] __up_console_sem+0x5e/0x70
[Wed Nov 27 00:38:46 2024] hardirqs last disabled at (8328):
[<ffffffffac230db3>] __up_console_sem+0x43/0x70
[Wed Nov 27 00:38:46 2024] softirqs last enabled at (6628):
[<ffffffffac135745>] __irq_exit_rcu+0x135/0x160
[Wed Nov 27 00:38:46 2024] softirqs last disabled at (6539):
[<ffffffffac135745>] __irq_exit_rcu+0x135/0x160
[Wed Nov 27 00:38:46 2024] ---[ end trace 0000000000000000 ]---
[Wed Nov 27 00:38:46 2024] VFS: Busy inodes after unmount of cifs (cifs)
[Wed Nov 27 00:38:46 2024] ------------[ cut here ]------------
[Wed Nov 27 00:38:46 2024] kernel BUG at fs/super.c:650!
[Wed Nov 27 00:38:46 2024] Oops: invalid opcode: 0000 [#1] PREEMPT SMP
KASAN NOPTI
[Wed Nov 27 00:38:46 2024] CPU: 2 UID: 0 PID: 316177 Comm: umount
Tainted: G W 6.12.0 #1
[Wed Nov 27 00:38:46 2024] Tainted: [W]=WARN
[Wed Nov 27 00:38:46 2024] Hardware name: Red Hat KVM, BIOS
1.16.3-2.el9 04/01/2014
[Wed Nov 27 00:38:46 2024] RIP: 0010:generic_shutdown_super+0x1b7/0x1c0
[Wed Nov 27 00:38:46 2024] Code: 7b 28 e8 5c ca f8 ff 48 8b 6b 28 48
89 ef e8 50 ca f8 ff 48 8b 55 00 48 8d b3 68 06 00 00 48 c7 c7 e0 38
ba ad e8 d9 c1 b5 ff <0f> 0b 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90
90 90 90 90 90 90
[Wed Nov 27 00:38:46 2024] RSP: 0018:ff1100012197fdf0 EFLAGS: 00010282
[Wed Nov 27 00:38:46 2024] RAX: 000000000000002d RBX: ff110001238b6000
RCX: 0000000000000027
[Wed Nov 27 00:38:46 2024] RDX: 0000000000000027 RSI: 0000000000000004
RDI: ff110004cb131a48
[Wed Nov 27 00:38:46 2024] RBP: ffffffffc1c6ac00 R08: ffffffffac3fd2fe
R09: ffe21c0099626349
[Wed Nov 27 00:38:46 2024] R10: ff110004cb131a4b R11: 0000000000000001
R12: ff110001238b69c0
[Wed Nov 27 00:38:46 2024] R13: ff110001238b6780 R14: 1fe220002432ffd4
R15: 0000000000000000
[Wed Nov 27 00:38:46 2024] FS: 00007fddc1dcc800(0000)
GS:ff110004cb100000(0000) knlGS:0000000000000000
[Wed Nov 27 00:38:46 2024] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[Wed Nov 27 00:38:46 2024] CR2: 00007fc6440095d0 CR3: 0000000142146005
CR4: 0000000000373ef0
[Wed Nov 27 00:38:46 2024] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[Wed Nov 27 00:38:46 2024] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[Wed Nov 27 00:38:46 2024] Call Trace:
[Wed Nov 27 00:38:46 2024] <TASK>
[Wed Nov 27 00:38:46 2024] ? die+0x37/0x90
[Wed Nov 27 00:38:46 2024] ? do_trap+0x133/0x230
[Wed Nov 27 00:38:46 2024] ? generic_shutdown_super+0x1b7/0x1c0
[Wed Nov 27 00:38:46 2024] ? do_error_trap+0x94/0x130
[Wed Nov 27 00:38:46 2024] ? generic_shutdown_super+0x1b7/0x1c0
[Wed Nov 27 00:38:46 2024] ? generic_shutdown_super+0x1b7/0x1c0
[Wed Nov 27 00:38:46 2024] ? handle_invalid_op+0x2c/0x40
[Wed Nov 27 00:38:46 2024] ? generic_shutdown_super+0x1b7/0x1c0
[Wed Nov 27 00:38:46 2024] ? exc_invalid_op+0x2f/0x50
[Wed Nov 27 00:38:46 2024] ? asm_exc_invalid_op+0x1a/0x20
[Wed Nov 27 00:38:46 2024] ? irq_work_claim+0x1e/0x40
[Wed Nov 27 00:38:46 2024] ? generic_shutdown_super+0x1b7/0x1c0
[Wed Nov 27 00:38:46 2024] kill_anon_super+0x22/0x40
[Wed Nov 27 00:38:46 2024] cifs_kill_sb+0x78/0x90 [cifs]
[Wed Nov 27 00:38:46 2024] deactivate_locked_super+0x69/0xf0
[Wed Nov 27 00:38:46 2024] cleanup_mnt+0x195/0x200
[Wed Nov 27 00:38:46 2024] task_work_run+0xec/0x150
[Wed Nov 27 00:38:46 2024] ? __pfx_task_work_run+0x10/0x10
[Wed Nov 27 00:38:46 2024] ? mark_held_locks+0x24/0x90
[Wed Nov 27 00:38:46 2024] syscall_exit_to_user_mode+0x269/0x2a0
[Wed Nov 27 00:38:46 2024] do_syscall_64+0x81/0x180
[Wed Nov 27 00:38:46 2024] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Wed Nov 27 00:38:46 2024] RIP: 0033:0x7fddc1ff43eb
[Wed Nov 27 00:38:46 2024] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f
1f 40 00 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa
b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15
f9 a9 0c 00 f7 d8
[Wed Nov 27 00:38:46 2024] RSP: 002b:00007ffe64be88d8 EFLAGS: 00000246
ORIG_RAX: 00000000000000a6
[Wed Nov 27 00:38:46 2024] RAX: 0000000000000000 RBX: 00005632106d4c20
RCX: 00007fddc1ff43eb
[Wed Nov 27 00:38:46 2024] RDX: 0000000000000000 RSI: 0000000000000000
RDI: 00005632106d9410
[Wed Nov 27 00:38:46 2024] RBP: 00007ffe64be89b0 R08: 00005632106d4010
R09: 0000000000000007
[Wed Nov 27 00:38:46 2024] R10: 0000000000000000 R11: 0000000000000246
R12: 00005632106d4d28
[Wed Nov 27 00:38:46 2024] R13: 0000000000000000 R14: 00005632106d9410
R15: 00005632106d5030
[Wed Nov 27 00:38:46 2024] </TASK>
[Wed Nov 27 00:38:46 2024] Modules linked in: cifs ccm cmac nls_utf8
cifs_arc4 nls_ucs2_utils cifs_md4 rpcsec_gss_krb5 auth_rpcgss nfsv4
dns_resolver nfs lockd grace netfs nf_conntrack_netbios_ns
nf_conntrack_broadcast nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct
nft_chain_nat nf_tables ebtable_nat ebtable_broute ip6table_nat
ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat
nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw
iptable_security ip_set ebtable_filter ebtables ip6table_filter
ip6_tables iptable_filter ip_tables sunrpc kvm_intel kvm virtio_net
net_failover failover virtio_balloon loop fuse dm_multipath nfnetlink
zram xfs bochs drm_client_lib drm_shmem_helper drm_kms_helper
crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel drm
sha512_ssse3 sha256_ssse3 sha1_ssse3 floppy virtio_blk qemu_fw_cfg
virtio_console [last unloaded: cifs]
[Wed Nov 27 00:38:46 2024] ---[ end trace 0000000000000000 ]---
[Wed Nov 27 00:38:46 2024] RIP: 0010:generic_shutdown_super+0x1b7/0x1c0
[Wed Nov 27 00:38:46 2024] Code: 7b 28 e8 5c ca f8 ff 48 8b 6b 28 48
89 ef e8 50 ca f8 ff 48 8b 55 00 48 8d b3 68 06 00 00 48 c7 c7 e0 38
ba ad e8 d9 c1 b5 ff <0f> 0b 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90
90 90 90 90 90 90
[Wed Nov 27 00:38:46 2024] RSP: 0018:ff1100012197fdf0 EFLAGS: 00010282
[Wed Nov 27 00:38:46 2024] RAX: 000000000000002d RBX: ff110001238b6000
RCX: 0000000000000027
[Wed Nov 27 00:38:46 2024] RDX: 0000000000000027 RSI: 0000000000000004
RDI: ff110004cb131a48
[Wed Nov 27 00:38:46 2024] RBP: ffffffffc1c6ac00 R08: ffffffffac3fd2fe
R09: ffe21c0099626349
[Wed Nov 27 00:38:46 2024] R10: ff110004cb131a4b R11: 0000000000000001
R12: ff110001238b69c0
[Wed Nov 27 00:38:46 2024] R13: ff110001238b6780 R14: 1fe220002432ffd4
R15: 0000000000000000
[Wed Nov 27 00:38:46 2024] FS: 00007fddc1dcc800(0000)
GS:ff110004cb100000(0000) knlGS:0000000000000000
[Wed Nov 27 00:38:46 2024] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[Wed Nov 27 00:38:46 2024] CR2: 00007fc6440095d0 CR3: 0000000142146005
CR4: 0000000000373ef0
[Wed Nov 27 00:38:46 2024] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[Wed Nov 27 00:38:46 2024] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
On Tue, Nov 26, 2024 at 3:50 PM Paul Aurich <paul@xxxxxxxxxxxxxx> wrote:
>
> On 2024-11-22 19:28:34 -0800, Paul Aurich wrote:
> >On 2024-11-21 23:05:51 -0300, Paulo Alcantara wrote:
> >>Hi Paul,
> >>
> >>Thanks for looking into this! Really appreciate it.
> >>
> >>Paul Aurich <paul@xxxxxxxxxxxxxx> writes:
> >>
> >>>The unmount process (cifs_kill_sb() calling close_all_cached_dirs()) can
> >>>race with various cached directory operations, which ultimately results
> >>>in dentries not being dropped and these kernel BUGs:
> >>>
> >>>BUG: Dentry ffff88814f37e358{i=1000000000080,n=/} still in use (2) [unmount of cifs cifs]
> >>>VFS: Busy inodes after unmount of cifs (cifs)
> >>>------------[ cut here ]------------
> >>>kernel BUG at fs/super.c:661!
> >>>
> >>>This happens when a cfid is in the process of being cleaned up when, and
> >>>has been removed from the cfids->entries list, including:
> >>>
> >>>- Receiving a lease break from the server
> >>>- Server reconnection triggers invalidate_all_cached_dirs(), which
> >>> removes all the cfids from the list
> >>>- The laundromat thread decides to expire an old cfid.
> >>>
> >>>To solve these problems, dropping the dentry is done in queued work done
> >>>in a newly-added cfid_put_wq workqueue, and close_all_cached_dirs()
> >>>flushes that workqueue after it drops all the dentries of which it's
> >>>aware. This is a global workqueue (rather than scoped to a mount), but
> >>>the queued work is minimal.
> >>
> >>Why does it need to be a global workqueue? Can't you make it per tcon?
> >
> >The problem with a per-tcon workqueue is I didn't see clean way to
> >deal with multiuser mounts and flushing the workqueue in
> >close_all_cached_dirs() -- when dealing with each individual tcon,
> >we're still holding tlink_tree_lock, so an arbitrary sleep seems
> >problematic.
> >
> >There could be a per-sb workqueue (stored in cifs_sb or the master
> >tcon) but is there a way to get back to the superblock / master tcon
> >with just a tcon (e.g. cached_dir_lease_break, when processing a lease
> >break)?
> >
> >>>The final cleanup work for cleaning up a cfid is performed via work
> >>>queued in the serverclose_wq workqueue; this is done separate from
> >>>dropping the dentries so that close_all_cached_dirs() doesn't block on
> >>>any server operations.
> >>>
> >>>Both of these queued works expect to invoked with a cfid reference and
> >>>a tcon reference to avoid those objects from being freed while the work
> >>>is ongoing.
> >>
> >>Why do you need to take a tcon reference?
> >
> >In the existing code (and my patch, without the refs), I was seeing an
> >intermittent use-after-free of the tcon or cached_fids struct by
> >queued work processing a lease break -- the cfid isn't linked from
> >cached_fids, but smb2_close_cached_fid invoking SMB2_close can race
> >with the unmount and cifs_put_tcon
> >
> >Something like:
> >
> > t1 t2
> >cached_dir_lease_break
> >smb2_cached_lease_break
> >smb2_close_cached_fid
> >SMB2_close starts
> > cifs_kill_sb
> > cifs_umount
> > cifs_put_link
> > cifs_put_tcon
> >SMB2_close continues
> >
> >I had a version of the patch that kept the 'in flight lease breaks' on
> >a second list in cached_fids so that they could be cancelled
> >synchronously from free_cached_fids(), but I struggled with it (I
> >can't remember exactly, but I think I was struggling to get the linked
> >list membership / removal handling and num_entries handling
> >consistent).
> >
> >>Can't you drop the dentries
> >>when tearing down tcon in cifs_put_tcon()? No concurrent mounts would
> >>be able to access or free it.
> >
> >The dentries being dropped must occur before kill_anon_super(), as
> >that's where the 'Dentry still in use' check is. All the tcons are put
> >in cifs_umount(), which occurs after:
> >
> > kill_anon_super(sb);
> > cifs_umount(cifs_sb);
> >
> >The other thing is that cifs_umount_begin() has this comment, which
> >made me think a tcon can actually be tied to two distinct mount
> >points:
> >
> > if ((tcon->tc_count > 1) || (tcon->status == TID_EXITING)) {
> > /* we have other mounts to same share or we have
> > already tried to umount this and woken up
> > all waiting network requests, nothing to do */
> >
> >Although, as I'm thinking about it again, I think I've misunderstood
> >(and that comment is wrong?).
> >
> >It did cross my mind to pull some of the work out of cifs_umount into
> >cifs_kill_sb (specifically, I wanted to cancel prune_tlinks earlier)
> >-- no prune_tlinks would make it more feasible to drop tlink_tree_lock
> >in close_all_cached_dirs(), at which point a per-tcon workqueue is
> >more practical.
> >
> >>After running xfstests I've seen a leaked tcon in
> >>/proc/fs/cifs/DebugData with no CIFS superblocks, which might be related
> >>to this.
> >>
> >>Could you please check if there is any leaked connection in
> >>/proc/fs/cifs/DebugData after running your tests?
> >
> >After I finish with my tests (I'm not using xfstests, although perhaps
> >I should be) and unmount the share, DebugData doesn't show any
> >connections for me.
>
> I was able to reproduce this leak. I believe the attached patch addresses it.
>
> I'm able to intermittently see a 'Dentry still in use' bug with xfstests
> generic/241 (what Steve saw) (the attached patch doesn't help with that). I'm
> still unsure what's going on there.
>
> >~Paul
--
Thanks,
Steve
