VERIFY3(insert_inode_locked(ip) == 0) failed (-16 == 0)

[nedbass]

Hit this panic on my desktop this morning.

[3616170.443896] VERIFY3(insert_inode_locked(ip) == 0) failed (-16 == 0)
[3616170.443903] SPLError: 23061:0:(zfs_znode.c:432:zfs_znode_alloc()) SPL PANIC
[3616170.443905] SPL: Showing stack for process 23061
[3616170.443907] Pid: 23061, comm: git Tainted: P        W  O 3.2.0-23-generic #36-Ubuntu
[3616170.443909] Call Trace:
[3616170.443930]  [<ffffffffa00694d7>] spl_debug_dumpstack+0x27/0x40 [spl]
[3616170.443936]  [<ffffffffa006a7b2>] spl_debug_bug+0x82/0xe0 [spl]
[3616170.443969]  [<ffffffffa01b8568>] zfs_znode_alloc+0x518/0x550 [zfs]
[3616170.443990]  [<ffffffffa01ba720>] zfs_zget+0x1a0/0x200 [zfs]
[3616170.444011]  [<ffffffffa0191bd1>] ? zap_lookup_norm+0xd1/0x1c0 [zfs]
[3616170.444031]  [<ffffffffa0198dc3>] zfs_dirent_lock+0x4c3/0x5d0 [zfs]
[3616170.444052]  [<ffffffffa0198f5b>] zfs_dirlook+0x8b/0x300 [zfs]
[3616170.444072]  [<ffffffffa0195aad>] ? zfs_zaccess+0x9d/0x430 [zfs]
[3616170.444080]  [<ffffffffa007b710>] ? tsd_exit+0x2a0/0x2d0 [spl]
[3616170.444100]  [<ffffffffa01b36e1>] zfs_lookup+0x2e1/0x330 [zfs]
[3616170.444121]  [<ffffffffa01c9e38>] zpl_lookup+0x78/0xf0 [zfs]
[3616170.444125]  [<ffffffff8165c46e>] ? _raw_spin_lock+0xe/0x20
[3616170.444129]  [<ffffffff811827e5>] d_alloc_and_lookup+0x45/0x90
[3616170.444132]  [<ffffffff8118ff25>] ? d_lookup+0x35/0x60
[3616170.444134]  [<ffffffff81184972>] do_lookup+0x202/0x310
[3616170.444138]  [<ffffffff8116319c>] ? kmem_cache_alloc_trace+0x10c/0x140
[3616170.444140]  [<ffffffff81185a90>] do_last+0xe0/0x730
[3616170.444142]  [<ffffffff81187481>] path_openat+0xd1/0x3f0
[3616170.444149]  [<ffffffffa007b710>] ? tsd_exit+0x2a0/0x2d0 [spl]
[3616170.444151]  [<ffffffff8165af6d>] ? mutex_lock+0x1d/0x50
[3616170.444153]  [<ffffffff811878c2>] do_filp_open+0x42/0xa0
[3616170.444157]  [<ffffffff81318ce1>] ? strncpy_from_user+0x31/0x40
[3616170.444158]  [<ffffffff81182c0a>] ? do_getname+0x10a/0x180
[3616170.444160]  [<ffffffff8165c46e>] ? _raw_spin_lock+0xe/0x20
[3616170.444164]  [<ffffffff81194b67>] ? alloc_fd+0xf7/0x150
[3616170.444167]  [<ffffffff81176f6d>] do_sys_open+0xed/0x220
[3616170.444168]  [<ffffffff811770c0>] sys_open+0x20/0x30
[3616170.444172]  [<ffffffff81664a82>] system_call_fastpath+0x16/0x1b

$  bass6@twist ~ /dev/pts/10 Mon Jul 28 10:46:45  >
uname -a
Linux twist 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
$  bass6@twist ~ /dev/pts/10 Mon Jul 28 10:47:55  >
dpkg -s zfs-dkms
Package: zfs-dkms
Status: install ok installed
Priority: extra
Section: kernel
Installed-Size: 11021
Maintainer: Darik Horn <dajhorn@vanadac.com>
Architecture: amd64
Source: zfs-linux
Version: 0.6.3-2~precise

[behlendorf]

This is a case I've actually looked in to in the past. It should only be able to happen if the same inode is being initialized concurrently from two different threads. Ideally, we'd just cleanly handle the error in this case but there's no easy way to handle the error this far in to the create path. But perhaps we could introduce some to ensure this can never happen.

[behlendorf]

Closing as out of date.