When zfs_sticky_remove_access() was originally adapted for Linux
a typo was made which altered the intended behavior. As described
in the block comment, the intended behavior is that permission
should be granted when the entry is a regular file and you have
write access. That is, S_ISREG should have been used instead of
S_ISDIR.
Restricting permission to regular files made good sense for older
systems where setting the bit on executable files would instruct
the system to save the program's text segment on the swap device.
On modern systems this behavior has been replaced by the sticky
bit acting as a restricted deletion flag and the plain file
restriction has been relaxed.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6889Closes#6910
5dc1ff29 changed the user space program to mount a zfs snapshot
from /bin/sh to /usr/bin/env. If the executable is not present
in the initramfs then snapshots cannot be automounted.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: James Dingwall <james.dingwall@zynstra.com>
Closes#5360Closes#6913
When the pool configuration contains a hole due to a previous device
removal ignore this top level vdev. Failure to do so will result in
the current configuration being assessed to have a non-uniform
replication level and the expected warning will be disabled.
The zpool_add_010_pos test case was extended to cover this scenario.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6907Closes#6911
Using zio_data_buf_alloc() to allocate the itx's may be unsafe
because the itx->itx_lr.lrc_reclen field is not constant from
allocation to free. Using a different itx->itx_lr.lrc_reclen
size in zio_data_buf_free() can result in the allocation being
returned to the wrong kmem cache.
This issue can be avoided entirely by storing the allocation size
in itx->itx_size and using that for zio_data_buf_free().
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6912
When d4a72f23 was merged, pss_pass_issued was incorrectly
added to the middle of the pool_scan_stat_t structure
instead of the end. This patch simply corrects this issue.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#6909
Fix a regression accidentally introduced in 1b81ab4 that prevents
'zfs get {user|group}objused@' from correctly reporting the requested
value.
Update "userspace_003_pos.ksh" and "groupspace_003_pos.ksh" to verify
this functionality.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#6908
Fix build errors with gcc 7.2.0 on Gentoo with kernel 4.14
built with CONFIG_GCC_PLUGIN_RANDSTRUCT=y such as:
module/nvpair/nvpair.c:2810:2:error:
positional initialization of field in ?struct? declared with
'designated_init' attribute [-Werror=designated-init]
nvs_native_nvlist,
^~~~~~~~~~~~~~~~~
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mark Wright <gienah@gentoo.org>
Closes#5390Closes#6903
The initramfs script was not honoring canmount=off. With this change,
it does. If the administrator has asked that a filesystem not be
mounted, that should be honored.
As an exception, the initramfs script ignores canmount=off on the
rootfs. The rootfs should not have canmount=off set either. However,
mounting it anyway seems harmless because it is being asked for
explicitly. The point of this exception is to avoid the risk of
breaking existing systems, just in case someone has canmount=off set on
their rootfs.
The initramfs still mounts filesystems with canmount=noauto. This is
necessary because it is typical to set that on the rootfs so that it can
be cloned. Without canmount=noauto, the clones' duplicate mountpoints
would conflict.
This is the remainder of the fix for:
https://github.com/zfsonlinux/pkg-zfs/issues/221
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#6897
For filesystems that are children of the rootfs, when mountpoint=none or
mountpoint=legacy, the initrafms script would assume a mountpoint based
on the dataset path. Given that the rootfs should have mountpoint=/ and
mountpoint inheritance is is the default behavior of ZFS, this behavior
seems unnecessary. In any event, it turns mountpoint=none into a no-op.
That removes this option from the administrator, and if someone uses it,
it does not work as expected. Worse yet, if the mountpoint directory
does not exist (which is the typical case for mountpoint=none), the
mounting and thus the boot process will fail. For the case of
mountpoint=legacy, the assumed mountpoint may not be the correct value
set in /etc/fstab.
This change makes the initramfs script not mount the filesystem in
either case. For mountpoint=none, this means we are correctly honoring
the setting. For mountpoint=legacy, there are two scenarios: If
canmount=on, the filesystem will be mounted by the normal mechanisms
later in the boot process. If canmount=noauto, the filesystem will not
be mounted at all, unless the administrator has done something special.
If they're not doing something special and they want it mounted by the
initramfs, they can simply not set mountpoint=legacy.
This is part of the fix for:
https://github.com/zfsonlinux/pkg-zfs/issues/221
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#6897
Resolve new warnings and errors from cppcheck v1.80.
* [lib/libshare/libshare.c:543]: (warning)
Possible null pointer dereference: protocol
* [lib/libzfs/libzfs_dataset.c:2323]: (warning)
Possible null pointer dereference: srctype
* [lib/libzfs/libzfs_import.c:318]: (error)
Uninitialized variable: link
* [module/zfs/abd.c:353]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:353]: (error) Uninitialized variable: i
* [module/zfs/abd.c:385]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:385]: (error) Uninitialized variable: i
* [module/zfs/abd.c:553]: (error) Uninitialized variable: i
* [module/zfs/abd.c:553]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:763]: (error) Uninitialized variable: i
* [module/zfs/abd.c:763]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:305]: (error) Uninitialized variable: tmp_page
* [module/zfs/zpl_xattr.c:342]: (warning)
Possible null pointer dereference: value
* [module/zfs/zvol.c:208]: (error) Uninitialized variable: p
Convert the following suppression to inline.
* [module/zfs/zfs_vnops.c:840]: (error)
Possible null pointer dereference: aiov
Exclude HAVE_UIO_ZEROCOPY and HAVE_DNLC from analysis since
these macro's will never be defined until this functionality
is implemented.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6879
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes#6882
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6882Closes#6883
Only access the `b_crypt_hdr` field of an ARC header if the content
is encrypted.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: DHE <git@dehacked.net>
Closes#6877
Currently, scrubs and resilvers can take an extremely
long time to complete. This is largely due to the fact
that zfs scans process pools in logical order, as
determined by each block's bookmark. This makes sense
from a simplicity perspective, but blocks in zfs are
often scattered randomly across disks, particularly
due to zfs's copy-on-write mechanisms.
This patch improves performance by splitting scrubs
and resilvers into a metadata scanning phase and an IO
issuing phase. The metadata scan reads through the
structure of the pool and gathers an in-memory queue
of I/Os, sorted by size and offset on disk. The issuing
phase will then issue the scrub I/Os as sequentially as
possible, greatly improving performance.
This patch also updates and cleans up some of the scan
code which has not been updated in several years.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Authored-by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Authored-by: Alek Pinchuk <apinchuk@datto.com>
Authored-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#3625Closes#6256
Remove unused library re and associated variable kstat_pobj. Add note
to documentation at start of program about required support for old
versions of Python. Change variable "format" (which is a built-in
function) to "fmt".
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6869
The correct way to determine if a dnode is dirty is to check
if any of the dn->dn_dirty_link's are active. Relying solely
on the dn->dn_dirtyctx can result in the dnode being mistakenly
reported as clean.
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3125Closes#6867
All of the ZTS test scripts specify /bin/ksh as the interpreter.
Unfortunately, as of Fedora 27 only /usr/bin/ksh is provided by
the package manager. Rather than change all the scripts to
accommodate the latest Fedora disable automatic dependencies
for the zfs-test package. Functionally this will not cause
any problems since /bin is a symlink to /usr/bin.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6868
Occasionally observed failure of zvol_ENOSPC_001_pos due to the
test case taking too long to complete. Disable the test case until
it can be improved.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #5848Closes#6862
On Linux, ftruncate(2) always changes the file timestamps, even if the
file size is not changed. However, in case of a successfull
truncate(2), the timestamps are updated only if the file size changes.
This translates to the VFS calling the ZFS Posix Layer "setattr"
function (zpl_setattr) with ATTR_MTIME and ATTR_CTIME unconditionally
set on the iattr mask only when doing a ftruncate(2), while the
truncate(2) is left to the filesystem implementation to be dealt with.
This behaviour is consistent with POSIX:2004/SUSv3 specifications
where there's no explicit requirement for file size changes to update
the timestamps only for ftruncate(2):
http://pubs.opengroup.org/onlinepubs/009695399/functions/truncate.htmlhttp://pubs.opengroup.org/onlinepubs/009695399/functions/ftruncate.html
This has been later updated in POSIX:2008/SUSv4 where, for both
truncate(2)/ftruncate(2), there's no mention of this size change
requirement:
http://austingroupbugs.net/view.php?id=489http://pubs.opengroup.org/onlinepubs/9699919799/functions/truncate.htmlhttp://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
Unfortunately the Linux VFS is still calling into the ZPL without
ATTR_MTIME/ATTR_CTIME set in the truncate(2) case: we fix this by
explicitly updating the timestamps when detecting the ATTR_SIZE bit,
which is always set in do_truncate(), on the iattr mask.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#6811Closes#6819
Travis builders have maximum work time ~49 minutes,
so we have to use 5 builders and spread the ZTS over
them using test group tags.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#6829
Prevents arc_summary.py crashing when called with parameter -d or
long form --description with Python3.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6849Closes#6850
If the receive or rollback is performed while filesystem is upgrading
the objset may be evicted in `dsl_dataset_clone_swap_sync_impl`. This
will lead to NULL pointer dereference when upgrade tries to access
evicted objset.
This commit adds long hold of dataset during whole upgrade process.
The receive and rollback will return an EBUSY error until the
upgrade is not finished.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arkadiusz Bubała <arkadiusz.bubala@open-e.com>
Closes#5295Closes#6837
After doing a recursive raw receive, zfs userspace performs
a final pass to adjust the encryption root hierarchy as
needed. Unfortunately, the FORCE_INHERIT ioctl had a bug
which caused the encryption root to always be assigned to
the direct parent instead of the inheriting parent. This
patch simply fixes this issue.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alek Pinchuk <apinchuk@datto.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#6847Closes#6848
In __dbuf_hold_impl(), if a buffer is currently syncing and is still
referenced from db_data, a copy is made in case it is dirtied again in
the txg. Previously, the buffer for the copy was simply allocated with
arc_alloc_buf() which doesn't handle compressed or encrypted buffers
(which are a special case of a compressed buffer). The result was
typically an invalid memory access because the newly-allocated buffer
was of the uncompressed size.
This commit fixes the problem by handling the 2 compressed cases,
encrypted and unencrypted, respectively, with arc_alloc_raw_buf() and
arc_alloc_compressed_buf().
Although using the proper allocation functions fixes the invalid memory
access by allocating a buffer of the compressed size, another unrelated
issue made it impossible to properly detect compressed buffers in the
first place. The header's compression flag was set to ZIO_COMPRESS_OFF
in arc_write() when it was possible that an attached buffer was actually
compressed. This commit adds logic to only set ZIO_COMPRESS_OFF in
the non-ZIO_RAW case which wil handle both cases of compressed buffers
(encrypted or unencrypted).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#5742Closes#6797
Add any missing variables for CI control to TEST.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes#6846
Some redundancy is present in the systemd dependencies, as
noticed in PR#6764. Existing setups might rely on these quirks,
so these cleanups have been moved to the development branch.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Antonio Russo <antonio.e.russo@gmail.com>
Closes#6822
This allows RPM-based systems to properly control package installation
and removal when using systemd.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#6838Closes#6841
Reviewed by: Yuri Pankov <yuripv@gmx.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Authored by: Toomas Soome <tsoome@me.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/8607
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/b852c2f5Closes#6842
A prior commit changed test-runner to enable tagging
of testgroups within a test suite runfile. They must
be specified in each runfile. Update the runfile for
performance regressions so it is properly tagged.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes#6830
Without any tag specified into the runtime-generated runfile the
test-runner will not execute the test provided from the command line:
fix this by adding tag information to the custom runfile.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#6826
Use automake to build initramfs scripts and hooks.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#6761
When the 128KB block is compressed to less than 4KB, the pointer
to the Footer is not in the end of the compressed buffer, that's
because the Header offset was added twice for this case. So there
is a gap between the Footer and the compressed buffer.
1. Always compute the Footer pointer address from the start of the
last page.
2. Remove the un-used workaroud code which has been verified fixed
with the latest driver and this fix.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Weigang Li <weigang.li@intel.com>
Closes#6827
Sort list of tunables printed by _tunable_summary()
alphabetically
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6828
By default additional dependencies are generated automatically for
packages. This is normally a good thing because it helps ensure
things just work. It doesn't make sense for the DKMS package which
requires minimal dependencies that can be easily listed.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6467Closes#6835
Fixed build regression in non-debug builds from recent cleanups of
c89 workarounds.
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes#6832
Rarely observed failure of zpool_import_missing_003_pos during
automated testing due to timeout. Disable the test case until
it can be improved.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Issue #6839Closes#6840
Include docstrings (PEP8, PEP257) for module and all functions.
Separately, remove outdated section in comment at start of
module. Separately, remove unused global constant "usetunable".
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6818
Complete rewrite of fHits(). Move units from non-standard English
abbreviations to SI units, thereby avoiding confusion because of
"long scale" and "short scale" numbers. Remove unused parameter
"Decimal". Add function string. Aim to confirm to PEP8.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6815
With PR 5756 the zfs module now supports c99 and the
remaining past c89 workarounds can be undone.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes#6816
Simplify and inline single-use function div1(); inline twice-used
function div2(); add function comment to zfs_header(); replace
variable "unused" in get_Kstat() with "_" following convention.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6802
* initramfs: Fix inconsistent whitespace
* initramfs: Fix a spelling error
* initramfs: Set elevator=noop on the rpool's disks
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#6807
Enable test-runner to accept a list of tags to identify
which test groups the user wishes to run.
Also allow test-runner to perform multiple iterations
of a test run.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Wren Kennedy <john.kennedy@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes#6788
ZFS already sets elevator=noop for wholedisk vdevs (for all pools), but
typical root-on-ZFS installations use partitions. This sets
elevator=noop on the disks in the root pool.
Ubuntu 16.04 and 16.10 had this. It was lost in 17.04 due to Debian
switching to this upstream initramfs script.
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Include the scan.coverity.com status badge in the top level README.
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6801
Porting Notes:
- The OpenZFS patch added nicenum_scale() and nicenum() to a
library not used by ZFS. Rather than pull in a new dependency
the version of nicenum in lib/libzpool/util.c was simply
replaced with the new one.
Reviewed by: Sebastian Wiedenroth <wiedi@frubar.net>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Yuri Pankov <yuripv@gmx.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Authored by: Jason King <jason.brian.king@gmail.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/640
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/0a055120Closes#6796
Replace if-elif-else construction with shorter loop;
remove unused parameter "Decimal"; centralize format
string; add function documentation string; conform to
PEP8.
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes#6784
