Authored by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
The refresh_config() calls into the kernel with ZFS_IOC_POOL_TRYIMPORT.
This ioctl returns the config of the pool in a buffer pre-allocated in
userland. The original estimate for the size is too conservative since
it doesn't account for the large size of vdev stats that are added to
the config before returning.
This fix simply increases the size of the buffer passed. This results in
a speed up of the zpool import process, and less spam in zfs_dbgmsg.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/7541
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/a3c7690Closes#5704
Authored by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/7340
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/ed4e7a6Closes#5681
Correctly handle the unlikely case where the memory buffer cannot be resized.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#5575
Authored by: Toomas Soome <tsoome@me.com>
Reviewed by: - George Wilson <george.wilson@delphix.com>
Reviewed by: - Yuri Pankov <yuri.pankov@nexenta.com>
Reviewed by: - Andrew Stormont <andyjstormont@gmail.com>
Reviewed by: - Albert Lee <trisk@omniti.com>
Approved by: - Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/5142
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/d5f26adCloses#5663
Porting notes:
- statvfs64 is replaced by statfs64.
- ZFS_SUPER_MAGIC definition moved in include/sys/fs/zfs.h
to share it between user and kernel space.
Authored by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/7336
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/dd862f6dCloses#5651
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/7571
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/ad2760aCloses#5638
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/7604
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/586fd65Closes#5629
Authored by: Andriy Gapon <andriy.gapon@clusterhq.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gordon.w.ross@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/6428
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c079fa4Closes#5628
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Haakan T Johansson <f96hajo@chalmers.se>
Closes#5547Closes#5543
Enable picky cstyle checks and resolve the new warnings. The vast
majority of the changes needed were to handle minor issues with
whitespace formatting. This patch contains no functional changes.
Non-whitespace changes are as follows:
* 8 times ; to { } in for/while loop
* fix missing ; in cmd/zed/agents/zfs_diagnosis.c
* comment (confim -> confirm)
* change endline , to ; in cmd/zpool/zpool_main.c
* a number of /* BEGIN CSTYLED */ /* END CSTYLED */ blocks
* /* CSTYLED */ markers
* change == 0 to !
* ulong to unsigned long in module/zfs/dsl_scan.c
* rearrangement of module_param lines in module/zfs/metaslab.c
* add { } block around statement after for_each_online_node
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Håkan Johansson <f96hajo@chalmers.se>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5465
This patch adds a command (-c) option to zpool status and zpool iostat. The
-c option allows you to run an arbitrary command on each vdev and display
the first line of output in zpool status/iostat. The environment vars
VDEV_PATH and VDEV_UPATH are set to the vdev's path and "underlying path"
before running the command. For device mapper, multipath, or partitioned
vdevs, VDEV_UPATH is the actual underlying /dev/sd* disk. This can be useful
if the command you're running requires a /dev/sd* device.
The patch also uses /sys/block/<dev>/slaves/ to lookup the underlying device
instead of using libdevmapper. This not only removes the libdevmapper
requirement at build time, but also allows you to resolve device mapper
devices without being root. This means that UDEV_UPATH get set correctly
when running zpool status/iostat as an unprivileged user.
Example:
$ zpool status -c 'echo I am $VDEV_PATH, $VDEV_UPATH'
NAME STATE READ WRITE CKSUM
mypool ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
mpatha ONLINE 0 0 0 I am /dev/mapper/mpatha, /dev/sdc
sdb ONLINE 0 0 0 I am /dev/sdb1, /dev/sdb
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#5368
Allow `zfs unshare <protocol> -a` command to share or unshare all datasets
of a given protocol, nfs or smb.
Additionally, enable most of ZFS Test Suite zfs_share/zfs_unshare test cases.
To work around some Illumos-specific functionalities ($SHARE/$UNSHARE) some
function wrappers were added around them.
Finally, fix and issue in smb_is_share_active() that would leave SMB shares
exported when invoking 'zfs unshare -a'
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#3238Closes#5367
Before adding the entry to the configuration verify that the
device can be opened exclusively. This ensures that as long
as multipathd is running the underlying multipath devices, which
otherwise appear identical to their /dev/mapper counterpart,
are pruned from the configuration.
Failure to do so can result in a result in the vdev appearing
as UNAVAIL when the vdev path provided to the kernel can't be
opened exclusively.
This check would normally be performed in zpool_open_func()
but placing it there would result in false positives because
it is called concurrently for many devices.
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5387
This patch addresses multiple 'zpool import' block device
indentification problems which are most likely to occur on a
system configured to use blkid, by_vdev paths, multipath and
failover. The symptom most commonly observed is the import
uses different path names to import the pool than would
normally be expected.
* When using blkid to identify vdevs the listed devices may
be added to the cache in any order. In order to apply the
preferred search order heuristic a zfs_path_order() function
was added to calculate the order given full path names.
* Since it's possible to have multiple block devices with
different vdev guids which refer to the same ZPOOL_CONFIG_PATH
the slice cache must be indexed by guid and name. By avoiding
collisions the preferred ordering can be maintaining even
when multiple block devices claim the same ZPOOL_CONFIG_PATH.
The preferred sorting by partition was never benefitial for
a Linux system and was removed as part of this change.
* When adding entries to the blkid cache avl_find/avl_insert
are used instead of avl_add because collisions are possible
and must be handled gracefully.
* For pools using multipath devices there are, at a minimum,
three devices where a vdev label may be read. They are the
dm-* device and each underlying /dev/sd* device. Due to the
way the block cache is implemented each of these devices may
have a different cached copy of the vdev label. This can
result in "ghost pools" which appear to persist even after
a 'zpool labelclear' has been done to the dm-* device. In
order to prevent this the vdev label is read with O_DIRECT
in order to bypass any caching to get the on-disk version.
* When opening a block device verify that vdev guid read from
the disk matches the expected vdev guid. This allows for bad
labels to be filtered out.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5359
Sometimes it is desirable to specifically disable one or several
features directly on the 'zpool create' command line.
$ zpool create -o feature@<feature>=disabled ...
Original-patch-by: Turbo Fredriksson <turbo@bayour.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#3460Closes#5142Closes#5324
Previously when a drive faulted, the statechange-led.sh script would lookup
the drive's LED sysfs entry in /sys/block/sd*/device/enclosure_device, and
turn it on. During testing we noticed that if you pulled out a drive, or if
the drive was so badly broken that it no longer appeared to Linux, that the
/sys/block/sd* path would be removed, and the script could not lookup the
LED entry.
To fix this, this patch looks up the disks's more persistent
"/sys/class/enclosure/X:X:X:X/Slot N" LED sysfs path at pool import. It then
passes that path to the statechange-led script to use, rather than having the
script look it up on the fly. This allows the script to turn on/off the slot
LEDs even when the drive is missing.
Closes#5309Closes#2375
1. Enable multipath autoreplace support for FMA.
This extends FMA autoreplace to work with multipath disks. This
requires libdevmapper to be installed at build time.
2. Turn on/off fault LEDs when VDEVs become degraded/faulted/online
Set ZED_USE_ENCLOSURE_LEDS=1 in zed.rc to have ZED turn on/off the enclosure
LED for a drive when a drive becomes FAULTED/DEGRADED. Your enclosure must
be supported by the Linux SES driver for this to work. The enclosure LED
scripts work for multipath devices as well. The scripts will clear the LED
when the fault is cleared.
3. Rate limit ZIO delay and checksum events so as not to flood ZED
ZIO delay and checksum events are rate limited to 5/sec in the zfs module.
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Don Brady <don.brady@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#2449Closes#3017Closes#5159
coverity scan CID:147654,type: Copy into fixed size buffer
- string operation may write past the end of the fixed-size
destination buffer
coverity scan CID:147690,type: Uninitialized scalar variable
- call zfs_prop_get first in case we use sourcetype and
share_sourcetype without initialization
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: GeLiXin <ge.lixin@zte.com.cn>
Closes#5253
When the exception branch exits, the buf is leaked.
Reviewed by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: luozhengzheng <luo.zhengzheng@zte.com.cn>
Closes#5262
The following new test cases need to have execute permissions set:
userquota/groupspace_003_pos.ksh
userquota/userquota_013_pos.ksh
userquota/userspace_003_pos.ksh
upgrade/upgrade_userobj_001_pos.ksh
upgrade/setup.ksh
upgrade/cleanup.ksh
The following source files accidentally were marked executable:
lib/libzpool/kernel.c
lib/libshare/nfs.c
lib/libzfs/libzfs_dataset.c
lib/libzfs/libzfs_util.c
tests/zfs-tests/cmd/rm_lnkcnt_zero_file/rm_lnkcnt_zero_file.c
tests/zfs-tests/cmd/dir_rd_update/dir_rd_update.c
cmd/zed/zed_exec.c
module/icp/core/kcf_sched.c
module/zfs/dsl_pool.c
module/zfs/arc.c
module/nvpair/nvpair.c
man/man5/zfs-module-parameters.5
Reviewed-by: GeLiXin <ge.lixin@zte.com.cn>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5241
Fixes ABI issues with fletcher4 code, adds support for
incremental updates, and adds ztest method for testing.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Closes#5164
The variable snapprops_nvlist was never initialized, so properties
were not applied to the received snapshot.
Additionally, add zfs_receive_013_pos.ksh script to ZFS test suite to exercise
'zfs receive' functionality for user properties.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#4338
This patch tracks dnode usage for each user/group in the
DMU_USER/GROUPUSED_OBJECT ZAPs. ZAP entries dedicated to dnode
accounting have the key prefixed with "obj-" followed by the UID/GID
in string format (as done for the block accounting).
A new SPA feature has been added for dnode accounting as well as
a new ZPL version. The SPA feature must be enabled in the pool
before upgrading the zfs filesystem. During the zfs version upgrade,
a "quotacheck" will be executed by marking all dnode as dirty.
ZoL-bug-id: https://github.com/zfsonlinux/zfs/issues/3500
Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Johann Lombardi <johann.lombardi@intel.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported by: Tony Hutter <hutter2@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/4185
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/45818ee
Porting Notes:
This code is ported on top of the Illumos Crypto Framework code:
b5e030c8db
The list of porting changes includes:
- Copied module/icp/include/sha2/sha2.h directly from illumos
- Removed from module/icp/algs/sha2/sha2.c:
#pragma inline(SHA256Init, SHA384Init, SHA512Init)
- Added 'ctx' to lib/libzfs/libzfs_sendrecv.c:zio_checksum_SHA256() since
it now takes in an extra parameter.
- Added CTASSERT() to assert.h from for module/zfs/edonr_zfs.c
- Added skein & edonr to libicp/Makefile.am
- Added sha512.S. It was generated from sha512-x86_64.pl in Illumos.
- Updated ztest.c with new fletcher_4_*() args; used NULL for new CTX argument.
- In icp/algs/edonr/edonr_byteorder.h, Removed the #if defined(__linux) section
to not #include the non-existant endian.h.
- In skein_test.c, renane NULL to 0 in "no test vector" array entries to get
around a compiler warning.
- Fixup test files:
- Rename <sys/varargs.h> -> <varargs.h>, <strings.h> -> <string.h>,
- Remove <note.h> and define NOTE() as NOP.
- Define u_longlong_t
- Rename "#!/usr/bin/ksh" -> "#!/bin/ksh -p"
- Rename NULL to 0 in "no test vector" array entries to get around a
compiler warning.
- Remove "for isa in $($ISAINFO); do" stuff
- Add/update Makefiles
- Add some userspace headers like stdio.h/stdlib.h in places of
sys/types.h.
- EXPORT_SYMBOL *_Init/*_Update/*_Final... routines in ICP modules.
- Update scripts/zfs2zol-patch.sed
- include <sys/sha2.h> in sha2_impl.h
- Add sha2.h to include/sys/Makefile.am
- Add skein and edonr dirs to icp Makefile
- Add new checksums to zpool_get.cfg
- Move checksum switch block from zfs_secpolicy_setprop() to
zfs_check_settable()
- Fix -Wuninitialized error in edonr_byteorder.h on PPC
- Fix stack frame size errors on ARM32
- Don't unroll loops in Skein on 32-bit to save stack space
- Add memory barriers in sha2.c on 32-bit to save stack space
- Add filetest_001_pos.ksh checksum sanity test
- Add option to write psudorandom data in file_write utility
All users of fletcher4 methods must call `fletcher_4_init()/_fini()`
There's no benchmarking overhead when called from user-space.
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
The error message in zpool_vdev_remove() said top-level devices
could be removed, but that has never been true.
Reported-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#4506Closes#5213
Authored by: Alex Deiter <alex.deiter@gmail.com>
Reviewed by: Alex Aizman alex.aizman@nexenta.com
Reviewed by: Alek Pinchuk alek.pinchuk@nexenta.com
Reviewed by: Roman Strashkin roman.strashkin@nexenta.com
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported-by: kernelOfTruth <kerneloftruth@gmail.com>
OpenZFS-issue: https://www.illumos.org/issues/6111
OpenZFS-commit: https://github.com/illumos/illumos-gate/commit/4a20c933Closes#5110
Porting notes:
There were changes from upstream due to the following commits:
- zfs send -p send properties only for snapshots that are actually sent
057485504e
- Produce a full snapshot list for zfs send -p
e890dd85a7
- Implement zfs_ioc_recv_new() for OpenZFS 2605
43e52eddb1
- OpenZFS 6314 - buffer overflow in dsl_dataset_name
ZFS_MAXNAMELEN was changed to the now used ZFS_MAX_DATASET_NAME_LEN since
eca7b76001
Fix misleading error message:
"The /dev/zfs device is missing and must be created.", if /etc/mtab is missing.
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Eric Desrochers <eric.desrochers@canonical.com>
Closes#4680Closes#5029
This first phase brings over the ZFS SLM module, zfs_mod.c, to handle
auto operations in response to disk events. Disk event monitoring is
provided from libudev and generates the expected payload schema for
zfs_mod. This work leverages the recently added devid and phys_path
strings in the vdev label.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Don Brady <don.brady@intel.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#4673
Always free mnpt memory on failure in the zfs_unmount() function.
In the zfs_unshare_proto() function mountpoint is a const and
should not be assigned.
Signed-off-by: cao.xuewen <cao.xuewen@zte.com.cn>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5054
perf: 2.75x faster ddt_entry_compare()
First 256bits of ddt_key_t is a block checksum, which are expected
to be close to random data. Hence, on average, comparison only needs to
look at first few bytes of the keys. To reduce number of conditional
jump instructions, the result is computed as: sign(memcmp(k1, k2)).
Sign of an integer 'a' can be obtained as: `(0 < a) - (a < 0)` := {-1, 0, 1} ,
which is computed efficiently. Synthetic performance evaluation of
original and new algorithm over 1G random keys on 2.6GHz Intel(R) Xeon(R)
CPU E5-2660 v3:
old 6.85789 s
new 2.49089 s
perf: 2.8x faster vdev_queue_offset_compare() and vdev_queue_timestamp_compare()
Compute the result directly instead of using conditionals
perf: zfs_range_compare()
Speedup between 1.1x - 2.5x, depending on compiler version and
optimization level.
perf: spa_error_entry_compare()
`bcmp()` is not suitable for comparator use. Use `memcmp()` instead.
perf: 2.8x faster metaslab_compare() and metaslab_rangesize_compare()
perf: 2.8x faster zil_bp_compare()
perf: 2.8x faster mze_compare()
perf: faster dbuf_compare()
perf: faster compares in spa_misc
perf: 2.8x faster layout_hash_compare()
perf: 2.8x faster space_reftree_compare()
perf: libzfs: faster avl tree comparators
perf: guid_compare()
perf: dsl_deadlist_compare()
perf: perm_set_compare()
perf: 2x faster range_tree_seg_compare()
perf: faster unique_compare()
perf: faster vdev_cache _compare()
perf: faster vdev_uberblock_compare()
perf: faster fuid _compare()
perf: faster zfs_znode_hold_compare()
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Richard Elling <richard.elling@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5033
This fix resolves warnings reported during compiling with different gcc
optimization levels in debug mode,
Test tools:
gcc version 4.4.7 20120313 (Red Hat 4.4.7-16) (GCC)
Linux version: 2.6.32-573.18.1.el6.x86_64, Red Hat Enterprise Linux Server release 6.1 (Santiago)
List of warnings:
CFLAGS=-O1 ./configure --enable-debug ;make
../../module/icp/core/kcf_sched.c: In function ‘kcf_aop_done’:
../../module/icp/core/kcf_sched.c:499: error: ‘fg’ may be used uninitialized in this function
../../module/icp/core/kcf_sched.c:499: note: ‘fg’ was declared here
CFLAGS=-Os ./configure --enable-debug ; make
libzfs_dataset.c: In function ‘zfs_prop_set_list’:
libzfs_dataset.c:1575: error: ‘nvl_len’ may be used uninitialized in this function
Signed-off-by: GeLiXin <ge.lixin@zte.com.cn>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5022
