diff options
| author | Brian Behlendorf <[email protected]> | 2019-09-10 13:42:30 -0700 |
|---|---|---|
| committer | GitHub <[email protected]> | 2019-09-10 13:42:30 -0700 |
| commit | 25f06d677a81a65ca98fa3d725ab5031a4864104 (patch) | |
| tree | 0ca39f861a6cbbc8aa858dc8857c8d327c33c889 /module/zfs/spa_misc.c | |
| parent | 562e1c0327be13bce43d81479bb113a1175569d4 (diff) | |
Fix /etc/hostid on root pool deadlock
Accidentally introduced by dc04a8c which now takes the SCL_VDEV lock
as a reader in zfs_blkptr_verify(). A deadlock can occur if the
/etc/hostid file resides on a dataset in the same pool. This is
because reading the /etc/hostid file may occur while the caller is
holding the SCL_VDEV lock as a writer. For example, to perform a
`zpool attach` as shown in the abbreviated stack below.
To resolve the issue we cache the system's hostid when initializing
the spa_t, or when modifying the multihost property. The cached
value is then relied upon for subsequent accesses.
Call Trace:
spa_config_enter+0x1e8/0x350 [zfs]
zfs_blkptr_verify+0x33c/0x4f0 [zfs] <--- trying read lock
zio_read+0x6c/0x140 [zfs]
...
vfs_read+0xfc/0x1e0
kernel_read+0x50/0x90
...
spa_get_hostid+0x1c/0x38 [zfs]
spa_config_generate+0x1a0/0x610 [zfs]
vdev_label_init+0xa0/0xc80 [zfs]
vdev_create+0x98/0xe0 [zfs]
spa_vdev_attach+0x14c/0xb40 [zfs] <--- grabbed write lock
Reviewed-by: loli10K <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #9256
Closes #9285
Diffstat (limited to 'module/zfs/spa_misc.c')
| -rw-r--r-- | module/zfs/spa_misc.c | 19 |
1 files changed, 4 insertions, 15 deletions
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c index a18f9604a..1ee110b54 100644 --- a/module/zfs/spa_misc.c +++ b/module/zfs/spa_misc.c @@ -668,6 +668,7 @@ spa_add(const char *name, nvlist_t *config, const char *altroot) spa->spa_proc = &p0; spa->spa_proc_state = SPA_PROC_NONE; spa->spa_trust_config = B_TRUE; + spa->spa_hostid = zone_get_hostid(NULL); spa->spa_deadman_synctime = MSEC2NSEC(zfs_deadman_synctime_ms); spa->spa_deadman_ziotime = MSEC2NSEC(zfs_deadman_ziotime_ms); @@ -2560,22 +2561,10 @@ spa_multihost(spa_t *spa) return (spa->spa_multihost ? B_TRUE : B_FALSE); } -unsigned long -spa_get_hostid(void) +uint32_t +spa_get_hostid(spa_t *spa) { - unsigned long myhostid; - -#ifdef _KERNEL - myhostid = zone_get_hostid(NULL); -#else /* _KERNEL */ - /* - * We're emulating the system's hostid in userland, so - * we can't use zone_get_hostid(). - */ - (void) ddi_strtoul(hw_serial, NULL, 10, &myhostid); -#endif /* _KERNEL */ - - return (myhostid); + return (spa->spa_hostid); } boolean_t |