diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
index 9d7eca978..a978a9db5 100644
--- a/include/sys/fs/zfs.h
+++ b/include/sys/fs/zfs.h
@@ -192,6 +192,7 @@ typedef enum {
ZFS_PROP_REDACT_SNAPS,
ZFS_PROP_SNAPSHOTS_CHANGED,
ZFS_PROP_PREFETCH,
+ ZFS_PROP_VOLTHREADING,
ZFS_NUM_PROPS
} zfs_prop_t;
diff --git a/include/sys/zvol.h b/include/sys/zvol.h
index 5e92a3367..c9eefbeb4 100644
--- a/include/sys/zvol.h
+++ b/include/sys/zvol.h
@@ -50,6 +50,7 @@ extern int zvol_get_stats(objset_t *, nvlist_t *);
extern boolean_t zvol_is_zvol(const char *);
extern void zvol_create_cb(objset_t *, void *, cred_t *, dmu_tx_t *);
extern int zvol_set_volsize(const char *, uint64_t);
+extern int zvol_set_volthreading(const char *, boolean_t);
extern int zvol_set_common(const char *, zfs_prop_t, zprop_source_t, uint64_t);
extern zvol_state_handle_t *zvol_suspend(const char *);
extern int zvol_resume(zvol_state_handle_t *);
diff --git a/include/sys/zvol_impl.h b/include/sys/zvol_impl.h
index 810320862..6c15c84b6 100644
--- a/include/sys/zvol_impl.h
+++ b/include/sys/zvol_impl.h
@@ -58,6 +58,7 @@ typedef struct zvol_state {
atomic_t zv_suspend_ref; /* refcount for suspend */
krwlock_t zv_suspend_lock; /* suspend lock */
struct zvol_state_os *zv_zso; /* private platform state */
+ boolean_t zv_threading; /* volthreading property */
} zvol_state_t;
diff --git a/lib/libzfs/libzfs.abi b/lib/libzfs/libzfs.abi
index 083c27be7..f8b0d3951 100644
--- a/lib/libzfs/libzfs.abi
+++ b/lib/libzfs/libzfs.abi
@@ -1868,7 +1868,8 @@
-
+
+
diff --git a/man/man7/zfsprops.7 b/man/man7/zfsprops.7
index 59f640437..9ff0236f4 100644
--- a/man/man7/zfsprops.7
+++ b/man/man7/zfsprops.7
@@ -1197,6 +1197,18 @@ are equivalent to the
and
.Sy noexec
mount options.
+.It Sy volthreading Ns = Ns Sy on Ns | Ns Sy off
+Controls internal zvol threading.
+The value
+.Sy off
+disables zvol threading, and zvol relies on application threads.
+The default value is
+.Sy on ,
+which enables threading within a zvol.
+Please note that this property will be overridden by
+.Sy zvol_request_sync
+module parameter.
+This property is only applicable to Linux.
.It Sy filesystem_limit Ns = Ns Ar count Ns | Ns Sy none
Limits the number of filesystems and volumes that can exist under this point in
the dataset tree.
diff --git a/module/os/linux/zfs/zvol_os.c b/module/os/linux/zfs/zvol_os.c
index 3dc0bb388..fd0fd2c36 100644
--- a/module/os/linux/zfs/zvol_os.c
+++ b/module/os/linux/zfs/zvol_os.c
@@ -512,7 +512,7 @@ zvol_request_impl(zvol_state_t *zv, struct bio *bio, struct request *rq,
uint64_t size = io_size(bio, rq);
int rw = io_data_dir(bio, rq);
- if (zvol_request_sync)
+ if (zvol_request_sync || zv->zv_threading == B_FALSE)
force_sync = 1;
zv_request_t zvr = {
@@ -1304,6 +1304,7 @@ zvol_os_create_minor(const char *name)
int error = 0;
int idx;
uint64_t hash = zvol_name_hash(name);
+ uint64_t volthreading;
bool replayed_zil = B_FALSE;
if (zvol_inhibit_dev)
@@ -1350,6 +1351,12 @@ zvol_os_create_minor(const char *name)
zv->zv_volsize = volsize;
zv->zv_objset = os;
+ /* Default */
+ zv->zv_threading = B_TRUE;
+ if (dsl_prop_get_integer(name, "volthreading", &volthreading, NULL)
+ == 0)
+ zv->zv_threading = volthreading;
+
set_capacity(zv->zv_zso->zvo_disk, zv->zv_volsize >> 9);
blk_queue_max_hw_sectors(zv->zv_zso->zvo_queue,
diff --git a/module/zcommon/zfs_prop.c b/module/zcommon/zfs_prop.c
index 29764674a..764993b45 100644
--- a/module/zcommon/zfs_prop.c
+++ b/module/zcommon/zfs_prop.c
@@ -628,6 +628,9 @@ zfs_prop_init(void)
ZVOL_DEFAULT_BLOCKSIZE, PROP_ONETIME,
ZFS_TYPE_VOLUME, "512 to 128k, power of 2", "VOLBLOCK", B_FALSE,
sfeatures);
+ zprop_register_index(ZFS_PROP_VOLTHREADING, "volthreading",
+ 1, PROP_DEFAULT, ZFS_TYPE_VOLUME, "on | off", "zvol threading",
+ boolean_table, sfeatures);
zprop_register_number(ZFS_PROP_USEDSNAP, "usedbysnapshots", 0,
PROP_READONLY, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "",
"USEDSNAP", B_FALSE, sfeatures);
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index d535d9031..c4e99b34a 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -2522,6 +2522,15 @@ zfs_prop_set_special(const char *dsname, zprop_source_t source,
case ZFS_PROP_VOLSIZE:
err = zvol_set_volsize(dsname, intval);
break;
+ case ZFS_PROP_VOLTHREADING:
+ err = zvol_set_volthreading(dsname, intval);
+ /*
+ * Set err to -1 to force the zfs_set_prop_nvlist code down the
+ * default path to set the value in the nvlist.
+ */
+ if (err == 0)
+ err = -1;
+ break;
case ZFS_PROP_SNAPDEV:
case ZFS_PROP_VOLMODE:
err = zvol_set_common(dsname, prop, source, intval);
diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index eb20d9828..d5f069399 100644
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -369,6 +369,20 @@ out:
return (SET_ERROR(error));
}
+/*
+ * Update volthreading.
+ */
+int
+zvol_set_volthreading(const char *name, boolean_t value)
+{
+ zvol_state_t *zv = zvol_find_by_name(name, RW_NONE);
+ if (zv == NULL)
+ return (ENOENT);
+ zv->zv_threading = value;
+ mutex_exit(&zv->zv_state_lock);
+ return (0);
+}
+
/*
* Sanity check volume block size.
*/