diff options
Diffstat (limited to 'module')
| -rw-r--r-- | module/os/freebsd/zfs/zvol_os.c | 90 |
1 files changed, 59 insertions, 31 deletions
diff --git a/module/os/freebsd/zfs/zvol_os.c b/module/os/freebsd/zfs/zvol_os.c index 450369192..ffd96d159 100644 --- a/module/os/freebsd/zfs/zvol_os.c +++ b/module/os/freebsd/zfs/zvol_os.c @@ -210,7 +210,6 @@ zvol_geom_open(struct g_provider *pp, int flag, int count) zvol_state_t *zv; int err = 0; boolean_t drop_suspend = B_FALSE; - boolean_t drop_namespace = B_FALSE; if (!zpool_on_zvol && tsd_get(zfs_geom_probe_vdev_key) != NULL) { /* @@ -226,6 +225,12 @@ zvol_geom_open(struct g_provider *pp, int flag, int count) retry: rw_enter(&zvol_state_lock, ZVOL_RW_READER); + /* + * Obtain a copy of private under zvol_state_lock to make sure either + * the result of zvol free code setting private to NULL is observed, + * or the zv is protected from being freed because of the positive + * zv_open_count. + */ zv = pp->private; if (zv == NULL) { rw_exit(&zvol_state_lock); @@ -233,18 +238,6 @@ retry: goto out_locked; } - if (zv->zv_open_count == 0 && !mutex_owned(&spa_namespace_lock)) { - /* - * We need to guarantee that the namespace lock is held - * to avoid spurious failures in zvol_first_open. - */ - drop_namespace = B_TRUE; - if (!mutex_tryenter(&spa_namespace_lock)) { - rw_exit(&zvol_state_lock); - mutex_enter(&spa_namespace_lock); - goto retry; - } - } mutex_enter(&zv->zv_state_lock); if (zv->zv_zso->zso_dying) { rw_exit(&zvol_state_lock); @@ -276,8 +269,27 @@ retry: ASSERT(MUTEX_HELD(&zv->zv_state_lock)); if (zv->zv_open_count == 0) { + boolean_t drop_namespace = B_FALSE; + ASSERT(ZVOL_RW_READ_HELD(&zv->zv_suspend_lock)); + + /* + * Take spa_namespace_lock to prevent lock inversion when + * zvols from one pool are opened as vdevs in another. + */ + if (!mutex_owned(&spa_namespace_lock)) { + if (!mutex_tryenter(&spa_namespace_lock)) { + mutex_exit(&zv->zv_state_lock); + rw_exit(&zv->zv_suspend_lock); + kern_yield(PRI_USER); + goto retry; + } else { + drop_namespace = B_TRUE; + } + } err = zvol_first_open(zv, !(flag & FWRITE)); + if (drop_namespace) + mutex_exit(&spa_namespace_lock); if (err) goto out_zv_locked; pp->mediasize = zv->zv_volsize; @@ -285,6 +297,8 @@ retry: pp->stripesize = zv->zv_volblocksize; } + ASSERT(MUTEX_HELD(&zv->zv_state_lock)); + /* * Check for a bad on-disk format version now since we * lied about owning the dataset readonly before. @@ -317,8 +331,6 @@ out_opened: out_zv_locked: mutex_exit(&zv->zv_state_lock); out_locked: - if (drop_namespace) - mutex_exit(&spa_namespace_lock); if (drop_suspend) rw_exit(&zv->zv_suspend_lock); return (err); @@ -859,10 +871,15 @@ zvol_cdev_open(struct cdev *dev, int flags, int fmt, struct thread *td) struct zvol_state_dev *zsd; int err = 0; boolean_t drop_suspend = B_FALSE; - boolean_t drop_namespace = B_FALSE; retry: rw_enter(&zvol_state_lock, ZVOL_RW_READER); + /* + * Obtain a copy of si_drv2 under zvol_state_lock to make sure either + * the result of zvol free code setting si_drv2 to NULL is observed, + * or the zv is protected from being freed because of the positive + * zv_open_count. + */ zv = dev->si_drv2; if (zv == NULL) { rw_exit(&zvol_state_lock); @@ -870,20 +887,12 @@ retry: goto out_locked; } - if (zv->zv_open_count == 0 && !mutex_owned(&spa_namespace_lock)) { - /* - * We need to guarantee that the namespace lock is held - * to avoid spurious failures in zvol_first_open. - */ - drop_namespace = B_TRUE; - if (!mutex_tryenter(&spa_namespace_lock)) { - rw_exit(&zvol_state_lock); - mutex_enter(&spa_namespace_lock); - goto retry; - } - } mutex_enter(&zv->zv_state_lock); - + if (zv->zv_zso->zso_dying) { + rw_exit(&zvol_state_lock); + err = SET_ERROR(ENXIO); + goto out_zv_locked; + } ASSERT3S(zv->zv_volmode, ==, ZFS_VOLMODE_DEV); /* @@ -909,12 +918,33 @@ retry: ASSERT(MUTEX_HELD(&zv->zv_state_lock)); if (zv->zv_open_count == 0) { + boolean_t drop_namespace = B_FALSE; + ASSERT(ZVOL_RW_READ_HELD(&zv->zv_suspend_lock)); + + /* + * Take spa_namespace_lock to prevent lock inversion when + * zvols from one pool are opened as vdevs in another. + */ + if (!mutex_owned(&spa_namespace_lock)) { + if (!mutex_tryenter(&spa_namespace_lock)) { + rw_exit(&zvol_state_lock); + mutex_enter(&spa_namespace_lock); + kern_yield(PRI_USER); + goto retry; + } else { + drop_namespace = B_TRUE; + } + } err = zvol_first_open(zv, !(flags & FWRITE)); + if (drop_namespace) + mutex_exit(&spa_namespace_lock); if (err) goto out_zv_locked; } + ASSERT(MUTEX_HELD(&zv->zv_state_lock)); + if ((flags & FWRITE) && (zv->zv_flags & ZVOL_RDONLY)) { err = SET_ERROR(EROFS); goto out_opened; @@ -949,8 +979,6 @@ out_opened: out_zv_locked: mutex_exit(&zv->zv_state_lock); out_locked: - if (drop_namespace) - mutex_exit(&spa_namespace_lock); if (drop_suspend) rw_exit(&zv->zv_suspend_lock); return (err); |