Commit Graph

980 Commits

Author SHA1 Message Date
Matthew Ahrens
6774931dfa
Extend zdb to print inconsistencies in livelists and metaslabs
Livelists and spacemaps are data structures that are logs of allocations
and frees.  Livelists entries are block pointers (blkptr_t). Spacemaps
entries are ranges of numbers, most often used as to track
allocated/freed regions of metaslabs/vdevs.

These data structures can become self-inconsistent, for example if a
block or range can be "double allocated" (two allocation records without
an intervening free) or "double freed" (two free records without an
intervening allocation).

ZDB (as well as zfs running in the kernel) can detect these
inconsistencies when loading livelists and metaslab.  However, it
generally halts processing when the error is detected.

When analyzing an on-disk problem, we often want to know the entire set
of inconsistencies, which is not possible with the current behavior.
This commit adds a new flag, `zdb -y`, which analyzes the livelist and
metaslab data structures and displays all of their inconsistencies.
Note that this is different from the leak detection performed by
`zdb -b`, which checks for inconsistencies between the spacemaps and the
tree of block pointers, but assumes the spacemaps are self-consistent.

The specific checks added are:

Verify livelists by iterating through each sublivelists and:
- report leftover FREEs
- report double ALLOCs and double FREEs
- record leftover ALLOCs together with their TXG [see Cross Check]

Verify spacemaps by iterating over each metaslab and:
- iterate over spacemap and then the metaslab's entries in the
  spacemap log, then report any double FREEs and double ALLOCs

Verify that livelists are consistenet with spacemaps.  The space
referenced by livelists (after using the FREE's to cancel out
corresponding ALLOCs) should be allocated, according to the spacemaps.

Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-66031
Closes #10515
2020-07-14 17:51:05 -07:00
Arvind Sankar
38e2e9ce83 Centralize variable substitution
A bunch of places need to edit files to incorporate the configured paths
i.e. bindir, sbindir etc. Move this logic into a common file.

Create arc_summary by copying arc_summary[23] as appropriate at build
time instead of install time.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10559
2020-07-14 17:33:44 -07:00
George Wilson
c15d36c674
Remove dependency on sharetab file and refactor sharing logic
== Motivation and Context

The current implementation of 'sharenfs' and 'sharesmb' relies on
the use of the sharetab file. The use of this file is os-specific
and not required by linux or freebsd. Currently the code must
maintain updates to this file which adds complexity and presents
a significant performance impact when sharing many datasets. In
addition, concurrently running 'zfs sharenfs' command results in
missing entries in the sharetab file leading to unexpected failures.

== Description

This change removes the sharetab logic from the linux and freebsd
implementation of 'sharenfs' and 'sharesmb'. It still preserves an
os-specific library which contains the logic required for sharing
NFS or SMB. The following entry points exist in the vastly simplified
libshare library:

- sa_enable_share -- shares a dataset but may not commit the change
- sa_disable_share -- unshares a dataset but may not commit the change
- sa_is_shared -- determine if a dataset is shared
- sa_commit_share -- notify NFS/SMB subsystem to commit the shares
- sa_validate_shareopts -- determine if sharing options are valid

The sa_commit_share entry point is provided as a performance enhancement
and is not required. The sa_enable_share/sa_disable_share may commit
the share as part of the implementation. Libshare provides a framework
for both NFS and SMB but some operating systems may not fully support
these protocols or all features of the protocol.

NFS Operation:
For linux, libshare updates /etc/exports.d/zfs.exports to add
and remove shares and then commits the changes by invoking
'exportfs -r'. This file, is automatically read by the kernel NFS
implementation which makes for better integration with the NFS systemd
service. For FreeBSD, libshare updates /etc/zfs/exports to add and
remove shares and then commits the changes by sending a SIGHUP to
mountd.

SMB Operation:
For linux, libshare adds and removes files in /var/lib/samba/usershares
by calling the 'net' command directly. There is no need to commit the
changes. FreeBSD does not support SMB.

== Performance Results

To test sharing performance we created a pool with an increasing number
of datasets and invoked various zfs actions that would enable and
disable sharing. The performance testing was limited to NFS sharing.
The following tests were performed on an 8 vCPU system with 128GB and
a pool comprised of 4 50GB SSDs:

Scale testing:
- Share all filesystems in parallel -- zfs sharenfs=on <dataset> &
- Unshare all filesystems in parallel -- zfs sharenfs=off <dataset> &

Functional testing:
- share each filesystem serially -- zfs share -a
- unshare each filesystem serially -- zfs unshare -a
- reset sharenfs property and unshare -- zfs inherit -r sharenfs <pool>

For 'zfs sharenfs=on' scale testing we saw an average reduction in time
of 89.43% and for 'zfs sharenfs=off' we saw an average reduction in time
of 83.36%.

Functional testing also shows a huge improvement:
- zfs share -- 97.97% reduction in time
- zfs unshare -- 96.47% reduction in time
- zfs inhert -r sharenfs -- 99.01% reduction in time

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Bryant G. Ly <bryangly@gmail.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
External-Issue: DLPX-68690
Closes #1603
Closes #7692
Closes #7943
Closes #10300
2020-07-13 09:19:18 -07:00
Serapheim Dimitropoulos
6f1db5f37e
Unconditionally enable debugging for libzpool
We already enable -DDEBUG unconditionally (meaning regardless
of this is a debug build or a performance build) for zdb and
ztest as they are mostly used for development and debugging.

This patch enables -DDEBUG for libzpool extending the debugging
checks for zdb, ztest, and a couple of other test utilities.

In addition to passing -DDEBUG we also enable -DZFS_DEBUG so
all assertion checks work s expected. We do so not only in
libzpool but in every utility that links to it, even if the
utility doesn't directly use any functionality wrapped in
ZFS_DEBUG macro definitions. The reason is that these utilities
may still include headers that contain structs that have more
fields when ZFS_DEBUG is defined. This can be a problem as
enabling that flag for libzpool but not for zdb can lead into
random problems (e.g. segmentation faults) as zdb may be have
an incorrect view of a struct passed to it by libzpool.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #10549
2020-07-10 15:30:31 -07:00
Arvind Sankar
3e597dee11 Use abs_top_builddir when referencing libraries
libtool stores absolute paths in the dependency_libs component of the
.la files. If the Makefile for a dependent library refers to the
libraries by relative path, some libraries end up duplicated on the link
command line.

As an example, libzfs specifies libzfs_core, libnvpair and libuutil as
dependencies to be linked in. The .la file for libzfs_core also
specifies libnvpair, but using an absolute path, with the result that
libnvpair is present twice in the linker command line for producing
libzfs.

While the only thing this causes is to slightly slow down the linking,
we can avoid it by using absolute paths everywhere, including for
convenience libraries just for consistency.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10538
2020-07-10 14:26:32 -07:00
Arvind Sankar
1537105a8c Add config.rpath for AM_GNU_GETTEXT
Commit e8864b1b28 ("config: libintl/libiconv for gettext() detection")
added an empty config.rpath with a comment that the real one doesn't
work with libtool.

However, an empty config.rpath doesn't really work: eg. on FreeBSD,
where libintl is in /usr/local/lib, configure thinks that gettext
doesn't exist and NLS should be disabled, which currently isn't
supported in the source, and hence requires manual workaround to
directly link -lintl without relying on configure. config.rpath is
essential to let it be detected either in --prefix or using
--with-libintl-prefix.

I also don't see the mentioned issue with libtool flags applied to
compilation, it seems to work fine to pass LTLIBINTL to libtool. It's
unnecessary to include LTLIBICONV as the configure test will
automatically append that to LTLIBINTL if it is necessary to link with
libiconv.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10538
2020-07-10 14:26:12 -07:00
Arvind Sankar
4d61ade1a3 Clean up lib dependencies
libzutil is currently statically linked into libzfs, libzfs_core and
libzpool. Avoid the unnecessary duplication by removing it from libzfs
and libzpool, and adding libzfs_core to libzpool.

Remove a few unnecessary dependencies:
- libuutil from libzfs_core
- libtirpc from libspl
- keep only libcrypto in libzfs, as we don't use any functions from
  libssl
- librt is only used for clock_gettime, however on modern systems that's
  in libc rather than librt. Add a configure check to see if we actually
  need librt
- libdl from raidz_test

Add a few missing dependencies:
- zlib to libefi and libzfs
- libuuid to zpool, and libuuid and libudev to zed
- libnvpair uses assertions, so add assert.c to provide aok and
  libspl_assertf

Sort the LDADD for programs so that libraries that satisfy dependencies
come at the end rather than the beginning of the linker command line.

Revamp the configure tests for libaries to use FIND_SYSTEM_LIBRARY
instead. This can take advantage of pkg-config, and it also avoids
polluting LIBS.

List all the required dependencies in the pkgconfig files, and move the
one for libzfs_core into the latter's directory. Install pkgconfig files
in $(libdir)/pkgconfig on linux and $(prefix)/libdata/pkgconfig on
FreeBSD, instead of /usr/share/pkgconfig, as the more correct location
for library .pc files.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10538
2020-07-10 14:26:00 -07:00
Brian Behlendorf
9a49d3f3d3
Add device rebuild feature
The device_rebuild feature enables sequential reconstruction when
resilvering.  Mirror vdevs can be rebuilt in LBA order which may
more quickly restore redundancy depending on the pools average block
size, overall fragmentation and the performance characteristics
of the devices.  However, block checksums cannot be verified
as part of the rebuild thus a scrub is automatically started after
the sequential resilver completes.

The new '-s' option has been added to the `zpool attach` and
`zpool replace` command to request sequential reconstruction
instead of healing reconstruction when resilvering.

    zpool attach -s <pool> <existing vdev> <new vdev>
    zpool replace -s <pool> <old vdev> <new vdev>

The `zpool status` output has been updated to report the progress
of sequential resilvering in the same way as healing resilvering.
The one notable difference is that multiple sequential resilvers
may be in progress as long as they're operating on different
top-level vdevs.

The `zpool wait -t resilver` command was extended to wait on
sequential resilvers.  From this perspective they are no different
than healing resilvers.

Sequential resilvers cannot be supported for RAIDZ, but are
compatible with the dRAID feature being developed.

As part of this change the resilver_restart_* tests were moved
in to the functional/replacement directory.  Additionally, the
replacement tests were renamed and extended to verify both
resilvering and rebuilding.

Original-patch-by: Isaac Huang <he.huang@intel.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: John Poduska <jpoduska@datto.com>
Co-authored-by: Mark Maybee <mmaybee@cray.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10349
2020-07-03 11:05:50 -07:00
Brian Behlendorf
67b1362f04 Style fixes
* Fix cstyle issue in shrinker.h which exceeded 80 columns.
* Silence shellcheck warning in zpool.d/smart script.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2020-06-27 17:38:55 -07:00
Allan Jude
3bc92b9ef6
Make zstreamdump output the size of the payload for BEGIN records
This is helpful for determining the size of the nvlist of snapshots
and properties

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes #10505
2020-06-27 10:29:47 -07:00
Matthew Ahrens
7b232e9354
arcstat: add 'avail', fix 'free'
The meaning of the `free` field is currently `zfs_arc_sys_free`, which
is the target amount of memory to leave free for the system, and is
constant after booting.

This commit changes the meaning of `free` to arc_free_memory(), the
amount of memory that the ARC considers to be free.

It also adds a new arcstat field `avail`, which tracks
`arc_available_memory()`.

Since `avail` can be negative, it also updates the arcstat script to
pretty-print negative values.

example output:

  $ arcstat -f time,miss,arcsz,c,grow,need,free,avail 1
      time  miss  arcsz     c  grow  need  free  avail
  15:03:02   39K   114G  114G     0     0  2.4G  407M
  15:03:03   42K   114G  114G     0     0  2.1G  120M
  15:03:04   40K   114G  114G     0     0  1.8G  -177M
  15:03:05   24K   113G  112G     0     0  1.7G  -269M
  15:03:06   29K   111G  110G     0     0  1.6G  -385M
  15:03:07   27K   110G  108G     0     0  1.4G  -535M
  15:03:08   13K   108G  108G     0     0  2.2G  239M
  15:03:09   33K   107G  107G     0     0  1.3G  -639M
  15:03:10   16K   105G  102G     0     0  2.6G  704M
  15:03:11  7.2K   102G  102G     0     0  5.1G  3.1G
  15:03:12   42K   103G  102G     0     0  4.8G  2.8G

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10494
2020-06-26 18:05:28 -07:00
Robert Novak
bfcbec6f5d
Add block histogram to zdb
The block histogram tracks the changes to psize, lsize and asize
both in the count of the number of blocks (by blocksize) and the
total length of all of the blocks for that blocksize.  It also
keeps a running total of the cumulative size of all of the blocks
up to each size to help determine the size of caching SSDs to be
added to zfs hardware deployments.

The block history counts and lengths are summarized in bins
which are powers of two. Even rows with counts of zero are printed.

This change is accessed by specifying one of two options:

zdb -bbb pool
zdb -Pbbb pool

The first version prints the table in fixed size columns.
The second prints in "parseable" output that can be placed into
a CSV file.

Fixed Column, nicenum output sample:
  block   psize                lsize                asize
   size   Count Length   Cum.  Count Length   Cum.  Count Length   Cum.
    512:  3.50K  1.75M  1.75M  3.43K  1.71M  1.71M  3.41K  1.71M  1.71M
     1K:  3.65K  3.67M  5.43M  3.43K  3.44M  5.15M  3.50K  3.51M  5.22M
     2K:  3.45K  6.92M  12.3M  3.41K  6.83M  12.0M  3.59K  7.26M  12.5M
     4K:  3.44K  13.8M  26.1M  3.43K  13.7M  25.7M  3.49K  14.1M  26.6M
     8K:  3.42K  27.3M  53.5M  3.41K  27.3M  53.0M  3.44K  27.6M  54.2M
    16K:  3.43K  54.9M   108M  3.50K  56.1M   109M  3.42K  54.7M   109M
    32K:  3.44K   110M   219M  3.41K   109M   218M  3.43K   110M   219M
    64K:  3.41K   218M   437M  3.41K   218M   437M  3.44K   221M   439M
   128K:  3.41K   437M   874M  3.70K   474M   911M  3.41K   437M   876M
   256K:  3.41K   874M  1.71G  3.41K   874M  1.74G  3.41K   874M  1.71G
   512K:  3.41K  1.71G  3.41G  3.41K  1.71G  3.45G  3.41K  1.71G  3.42G
     1M:  3.41K  3.41G  6.82G  3.41K  3.41G  6.86G  3.41K  3.41G  6.83G
     2M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     4M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     8M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
    16M:      0      0  6.82G      0      0  6.86G      0      0  6.83G

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Robert E. Novak <novak5@llnl.gov>
Closes: #9158 
Closes #10315
2020-06-26 15:09:20 -07:00
Arvind Sankar
6b99fc0620 Fixes for make dist
Reduce the usage of EXTRA_DIST. If files are conditionally included in
_SOURCES, _HEADERS etc, automake is smart enough to dist all files that
could possibly be included, but this does not apply to EXTRA_DIST,
resulting in make dist depending on the configuration.

Add some files that were missing altogether in various Makefile's.

The changes to disted files in this commit (excluding deleted files):

+./cmd/zed/agents/README.md
+./etc/init.d/README.md
+./lib/libspl/os/freebsd/getexecname.c
+./lib/libspl/os/freebsd/gethostid.c
+./lib/libspl/os/freebsd/getmntany.c
+./lib/libspl/os/freebsd/mnttab.c
-./lib/libzfs/libzfs_core.pc
-./lib/libzfs/libzfs.pc
+./lib/libzfs/os/freebsd/libzfs_compat.c
+./lib/libzfs/os/freebsd/libzfs_fsshare.c
+./lib/libzfs/os/freebsd/libzfs_ioctl_compat.c
+./lib/libzfs/os/freebsd/libzfs_zmount.c
+./lib/libzutil/os/freebsd/zutil_compat.c
+./lib/libzutil/os/freebsd/zutil_device_path_os.c
+./lib/libzutil/os/freebsd/zutil_import_os.c
+./module/lua/README.zfs
+./module/os/linux/spl/README.md
+./tests/README.md
+./tests/zfs-tests/tests/functional/cli_root/zfs_clone/zfs_clone_rm_nested.ksh
+./tests/zfs-tests/tests/functional/cli_root/zfs_send/zfs_send_encrypted_unloaded.ksh
+./tests/zfs-tests/tests/functional/inheritance/README.config
+./tests/zfs-tests/tests/functional/inheritance/README.state
+./tests/zfs-tests/tests/functional/rsend/rsend_016_neg.ksh
+./tests/zfs-tests/tests/perf/fio/sequential_readwrite.fio

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10501
2020-06-26 14:20:02 -07:00
Arvind Sankar
5ca349f95d Fix check for sed --in-place
The test added in commit
  4313a5b4c5 ("Detect if sed supports --in-place")
doesn't work at least on my system (autoconfig-2.69).

The issue is that SED has already been found and cached before this
function is evaluated, with the result that the test is completely
skipped.

...
checking for a sed that does not truncate output... /usr/bin/sed
...
checking for sed --in-place... (cached) /usr/bin/sed

The first test is executed by libtool.m4. This looks to have been around
in libtool for at least 15 years or so, not sure why this was not
encountered at the time of the original commit.

Fix this by caching the value of the ac_inplace flag rather than the
path to SED. Also use $SED and add AC_REQUIRE to ensure that we use the
sed that was located by the standard configure test.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10493
2020-06-24 18:19:59 -07:00
Kevin P. Fleming
f21de6883f
Add trim_finish notify script for ZED
Allow users to configure notifications when TRIM operations are
completed on pools. Unlike resilver_finish and scrub_finish,
the trim_finish event is generated for each vdev in the pool
which was trimmed, so the script will generate a notification
for each one.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kevin P. Fleming <kevin@km6g.us>
Closes #10491
2020-06-24 16:57:13 -07:00
Jorgen Lundman
68301ba20e
zed additional features
This commit adds two features to zed, that macOS desires. The first
is that when you unload the kernel module, zed would enter into a
cpubusy loop calling zfs_events_next() repeatedly. We now look for
ENODEV, returned by kernel, so zed can exit gracefully.

Second feature is -I (idle) (alas -P persist was taken) is for the
deamon to;

1; if started without ZFS kernel module, stick around waiting for it.
2; if kernel module is unloaded, go back to 1.

This is due to daemons in macOS is started by launchctl, and is
expected to stick around.

Currently, the busy loop only exists when errno is ENODEV. This is
to ensure that functionality that upstream expects is not changed.
It did not care about errors before, and it still does not. (with the
exception of ENODEV).

However, it is probably better that all errors
(ERESTART notwithstanding) exits the loop, and the issues complaining
about zed taking all CPU will go away.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes #10476
2020-06-22 09:53:34 -07:00
Serapheim Dimitropoulos
42d8d1d66a
Remove unnecessary terminology from error-injection in ztest
Rephrase error-injection comment in ztest to be more clear.

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #10482
2020-06-22 09:48:36 -07:00
Andriy Gapon
a8bd6dcf87
zfs allow/unallow should work with numeric uid/gid
And that should work even (especially) if there is no matching user or
group name.  The change is originally by Xin Lin <delphij@FreeBSD.org>.

Original-patch-by: Xin Li <delphij@FreeBSD.org>
Reviewed-by: Yuri Pankov <yuri.pankov@nexenta.com>
Reviewed-by: Andy Stormont <astormont@racktopsystems.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Andriy Gapon <avg@FreeBSD.org>
Closes #9792 
Closes #10280
2020-06-19 10:38:43 -07:00
Arvind Sankar
60356b1a21 Add include files for prototypes
Include the header with prototypes in the file that provides definitions
as well, to catch any mismatch between prototype and definition.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470
2020-06-18 12:21:25 -07:00
Arvind Sankar
c3fe42aabd Remove dead code
Delete unused functions.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470
2020-06-18 12:21:18 -07:00
Arvind Sankar
65c7cc49bf Mark functions as static
Mark functions used only in the same translation unit as static. This
only includes functions that do not have a prototype in a header file
either.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470
2020-06-18 12:20:38 -07:00
Jorgen Lundman
d553fb9b9e
Avoid adding new primitives in zpool wait
zpool wait brought in sem_init() and family, which is a primitive set
not previously used in Open ZFS. It also happens to be deprecated
on macOS. Replace with phtread API calls.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Gallagher <john.gallagher@delphix.com>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes #10468
2020-06-18 10:44:45 -07:00
Matthew Ahrens
ba54b180a5
Remove refences to blacklist/whitelist
These terms reinforce the incorrect notion that black is bad and white
is good.

Replace this language with more specific terms which are also more clear
and don't rely on metaphor.  Specifically:

* When vdevs are specified on the command line, they are the "selected"
vdevs.

* Entries in /dev/ which should not be considered as possible disks are
"excluded" devices.

Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10457
2020-06-16 11:41:45 -07:00
Matthew Ahrens
f66434268c
Remove unnecessary references to slavery
The horrible effects of human slavery continue to impact society.  The
casual use of the term "slave" in computer software is an unnecessary
reference to a painful human experience.

This commit removes all possible references to the term "slave".

Implementation notes:

The zpool.d/slaves script is renamed to dm-deps, which uses the same
terminology as `dmsetup deps`.

References to the `/sys/class/block/$dev/slaves` directory remain.  This
directory name is determined by the Linux kernel.  Although
`dmsetup deps` provides the same information, it unfortunately requires
elevated privileges, whereas the `/sys/...` directory is world-readable.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10435
2020-06-10 17:07:59 -07:00
Arvind Sankar
66786f7943 Fix VPATH builds for user config
cmd/zpool and lib/libzutil Makefile's use -I., which won't work with a
VPATH build. Replace it with -I$(srcdir) instead.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10379
Closes #10421
2020-06-10 09:25:37 -07:00
Matthew Ahrens
7bcb7f0840
File incorrectly zeroed when receiving incremental stream that toggles -L
Background:

By increasing the recordsize property above the default of 128KB, a
filesystem may have "large" blocks.  By default, a send stream of such a
filesystem does not contain large WRITE records, instead it decreases
objects' block sizes to 128KB and splits the large blocks into 128KB
blocks, allowing the large-block filesystem to be received by a system
that does not support the `large_blocks` feature.  A send stream
generated by `zfs send -L` (or `--large-block`) preserves the large
block size on the receiving system, by using large WRITE records.

When receiving an incremental send stream for a filesystem with large
blocks, if the send stream's -L flag was toggled, a bug is encountered
in which the file's contents are incorrectly zeroed out.  The contents
of any blocks that were not modified by this send stream will be lost.
"Toggled" means that the previous send used `-L`, but this incremental
does not use `-L` (-L to no-L); or that the previous send did not use
`-L`, but this incremental does use `-L` (no-L to -L).

Changes:

This commit addresses the problem with several changes to the semantics
of zfs send/receive:

1. "-L to no-L" incrementals are rejected.  If the previous send used
`-L`, but this incremental does not use `-L`, the `zfs receive` will
fail with this error message:

    incremental send stream requires -L (--large-block), to match
    previous receive.

2. "no-L to -L" incrementals are handled correctly, preserving the
smaller (128KB) block size of any already-received files that used large
blocks on the sending system but were split by `zfs send` without the
`-L` flag.

3. A new send stream format flag is added, `SWITCH_TO_LARGE_BLOCKS`.
This feature indicates that we can correctly handle "no-L to -L"
incrementals.  This flag is currently not set on any send streams.  In
the future, we intend for incremental send streams of snapshots that
have large blocks to use `-L` by default, and these streams will also
have the `SWITCH_TO_LARGE_BLOCKS` feature set. This ensures that streams
from the default use of `zfs send` won't encounter the bug mentioned
above, because they can't be received by software with the bug.

Implementation notes:

To facilitate accessing the ZPL's generation number,
`zfs_space_delta_cb()` has been renamed to `zpl_get_file_info()` and
restructured to fill in a struct with ZPL-specific info including owner
and generation.

In the "no-L to -L" case, if this is a compressed send stream (from
`zfs send -cL`), large WRITE records that are being written to small
(128KB) blocksize files need to be decompressed so that they can be
written split up into multiple blocks.  The zio pipeline will recompress
each smaller block individually.

A new test case, `send-L_toggle`, is added, which tests the "no-L to -L"
case and verifies that we get an error for the "-L to no-L" case.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #6224 
Closes #10383
2020-06-09 10:41:01 -07:00
George Amanakis
b7654bd794
Trim L2ARC
The l2arc_evict() function is responsible for evicting buffers which
reference the next bytes of the L2ARC device to be overwritten. Teach
this function to additionally TRIM that vdev space before it is
overwritten if the device has been filled with data. This is done by
vdev_trim_simple() which trims by issuing a new type of TRIM,
TRIM_TYPE_SIMPLE.

We also implement a "Trim Ahead" feature. It is a zfs module parameter,
expressed in % of the current write size. This trims ahead of the
current write size. A minimum of 64MB will be trimmed. The default is 0
which disables TRIM on L2ARC as it can put significant stress to
underlying storage devices. To enable TRIM on L2ARC we set
l2arc_trim_ahead > 0.

We also implement TRIM of the whole cache device upon addition to a
pool, pool creation or when the header of the device is invalid upon
importing a pool or onlining a cache device. This is dependent on
l2arc_trim_ahead > 0. TRIM of the whole device is done with
TRIM_TYPE_MANUAL so that its status can be monitored by zpool status -t.
We save the TRIM state for the whole device and the time of completion
on-disk in the header, and restore these upon L2ARC rebuild so that
zpool status -t can correctly report them. Whole device TRIM is done
asynchronously so that the user can export of the pool or remove the
cache device while it is trimming (ie if it is too slow).

We do not TRIM the whole device if persistent L2ARC has been disabled by
l2arc_rebuild_enabled = 0 because we may not want to lose all cached
buffers (eg we may want to import the pool with
l2arc_rebuild_enabled = 0 only once because of memory pressure). If
persistent L2ARC has been disabled by setting the module parameter
l2arc_rebuild_blocks_min_l2size to a value greater than the size of the
cache device then the whole device is trimmed upon creation or import of
a pool if l2arc_trim_ahead > 0.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Adam D. Moss <c@yotes.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #9713
Closes #9789 
Closes #10224
2020-06-09 10:15:08 -07:00
Brian Behlendorf
c1f3de18a4
ztest: Fix spa_open() ENOENT failures
The pool may not be imported when the previous pass is terminated.
In which case, spa_open() will return ENOENT to indicate the pool
is not currently imported.  Refactor to code slightly to handle
this case by importing the pool and then retrying the spa_open().

The ztest_import() function was moved before ztest_run() and the
import logic split in to a small internal helper function.  The
ztest_freeze() function was also moved but no changes were made.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10407
2020-06-06 12:51:35 -07:00
Brian Behlendorf
3d93161b01
ztest: Fix ztest_run_zdb() failure
It's possible for ztest to be killed while the pool is exported
which results in an empty cache file.  This is a valid state to
test, but the validation check performed by ztest_run_zdb()
depends on the pool being in the cache file.  If it's not the
following error is printed.

    zdb -bccsv -G -d -Y -U /tmp/zloop-run/zpool.cache ztest
    zdb: can't open '/tmp/zloop-run': No such file or directory

Resolve these failures by removing the dependency on the cache
file.  Functionally, we only care that the pool can be imported
and that the zdb verification passes.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10385
2020-05-29 21:14:10 -07:00
Brian Behlendorf
d1b84da8c1
Revert "Let zfs mount all tolerate in-progress mounts"
This reverts commit a9cd8bf which introduced a segfault when running
`zfs mount -a` multiple times when there are mountpoints which are
not empty.  This segfault is now seen frequently by the CI after
the mount code was updated to directly call mount(2).

The original reason this logic was added is described in #8881.
Since then the systemd `zfs-share.target` has been updated to run
"After" the `zfs-mount.server` which should avoid this issue.

Reviewed-by: Don Brady <don.brady@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9560
Closes #10364
2020-05-26 16:07:50 -07:00
felixdoerre
501a1511ae
mount: use the mount syscall directly
Allow zfs datasets to be mounted on Linux without relying on the
invocation of an external processes.  This is the same behavior
which is implemented for FreeBSD.

Use of the libmount library was originally considered because it 
provides functionality to properly lock and update the /etc/mtab 
file.  However, these days /etc/mtab is typically a symlink to 
/proc/self/mounts so there's nothing to updated.  Therefore, we
call mount(2) directly and avoid any additional dependencies. 

If required the legacy behavior can be enabled by setting the 
ZFS_MOUNT_HELPER environment variable.  This may be needed in
environments where SELinux in enabled and the zfs binary does  
not have mount permission.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Felix Dörre <felix@dogcraft.de>
#10294
2020-05-20 18:02:41 -07:00
Paul Dagnelie
de4f06c275
Small program that converts a dataset id and an object id to a path
Small program that converts a dataset id and an object id to a path

Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #10204
2020-05-20 10:05:33 -07:00
George Amanakis
7cd723e685
Fix gcc 10.1 stringop-truncation error
As we do not expect the destination of these strncpy calls to be NULL
terminated, substitute them with memcpy.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10346
2020-05-19 14:24:10 -07:00
AJ Jordan
b29e31d80d Fix outdated comment header
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: AJ Jordan <alex@strugee.net>
Closes #10288
2020-05-11 16:23:16 -07:00
AJ Jordan
2b21da4f76 Fix inconsistent capitalization in arcstat -v
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: AJ Jordan <alex@strugee.net>
Closes #10288
2020-05-11 16:21:08 -07:00
Petros Koutoupis
bd95f00d4b
Fixed LDADD library links in Makefiles for cross compilation builds
When building on native dev system, there are no issues but when
cross-compiling for target system, some linker errors are observed.
The only way to avoid these errors is by adjusting the Makefile.am
of those various components to add the library dependencies.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Petros Koutoupis <petros@petroskoutoupis.com>
Closes #10304
2020-05-09 10:17:08 -07:00
George Amanakis
657fd33bcf
Improvements on persistent L2ARC
Functional changes:

We implement refcounts of log blocks and their aligned size on the
cache device along with two corresponding arcstats. The refcounts are
reflected in the header of the device and provide valuable information
as to whether log blocks are accounted for correctly. These are
dynamically adjusted as log blocks are committed/evicted. zdb also uses
this information in the device header and compares it to the
corresponding values as reported by dump_l2arc_log_blocks() which
emulates l2arc_rebuild(). If the refcounts saved in the device header
report higher values, zdb exits with an error. For this feature to work
correctly there should be no active writes on the device. This is also
employed in the tests of persistent L2ARC. We extend the structure of
the cache device header by adding the two new variables mirroring the
refcounts after the existing variables to preserve backward
compatibility in terms of persistent L2ARC.

1) a new arcstat "l2_log_blk_asize" and refcount "l2ad_lb_asize" which
   reflect the total aligned size of log blocks on the device. This is
   also reflected in the header of the cache device as "dh_lb_asize".
2) a new arcstat "l2arc_log_blk_count" and refcount "l2ad_lb_count"
   which reflect the total number of L2ARC log blocks present on cache
   devices.  It is also reflected in the header of the cache device as
   "dh_lb_count".

In l2arc_rebuild_vdev() if the amount of committed log entries in a log
block is 0 and the device header is valid we update the device header.
This will facilitate trimming of the whole device in this case when
TRIM for L2ARC is implemented.

Improve loop protection in l2arc_rebuild() by using the starting offset
of the payload of each log block instead of the starting offset of the
log block.

If the zio in l2arc_write_buffers() fails, restore the lbps array in the
header of the device to its previous state in l2arc_write_done().

If l2arc_rebuild() ends the rebuild process without restoring any L2ARC
log blocks in ARC and without any other error, this means that the lbps
array in the header is pointing to non-existent or invalid log blocks.
Reset the device header in this case.

In l2arc_rebuild() change the zfs_dbgmsg messages to
spa_history_log_internal() making them user visible with zpool history
command.

Non-functional changes:

Make the first test in persistent L2ARC use `zdb -lll` to increase
coverage in `zdb.c`.

Rename psize with asize when referring to log blocks, since
L2ARC_SET_PSIZE stores the vdev aligned size for log blocks. Also
rename dh_log_blk_entries to dh_log_entries to make it clear that
it is a mirror of l2ad_log_entries. Added comments for both changes.

Fix inaccurate comments for example in l2arc_log_blk_restore().

Add asserts at the end in l2arc_evict() and l2arc_write_buffers().

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10228
2020-05-07 16:34:03 -07:00
Paul Dagnelie
108a454a46
Add support for boot environment data to be stored in the label
Modern bootloaders leverage data stored in the root filesystem to 
enable some of their powerful features. GRUB specifically has a grubenv 
file which can store large amounts of configuration data that can be 
read and written at boot time and during normal operation. This allows 
sysadmins to configure useful features like automated failover after 
failed boot attempts. Unfortunately, due to the Copy-on-Write nature 
of ZFS, the standard behavior of these tools cannot handle writing to
ZFS files safely at boot time. We need an alternative way to store 
data that allows the bootloader to make changes to the data.

This work is very similar to work that was done on Illumos to enable 
similar functionality in the FreeBSD bootloader. This patch is different 
in that the data being stored is a raw grubenv file; this file can store 
arbitrary variables and values, and the scripting provided by grub is 
powerful enough that special structures are not required to implement 
advanced behavior.

We repurpose the second padding area in each label to store the grubenv 
file, protected by an embedded checksum. We add two ioctls to get and 
set this data, and libzfs_core and libzfs functions to access them more 
easily. There are no direct command line interfaces to these functions; 
these will be added directly to the bootloader utilities.

Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #10009
2020-05-07 09:36:33 -07:00
Philip Pokorny
a36bad1759
Fix column width calculation issue with certain terminal widths
If the reported terminal width is 0 or less than 42, the signed variable
width was set to a negative number that was then assigned to the
unsigned column width becoming a huge number.

Add comments and change logic to better explain what's happening.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Philip Pokorny <ppokorny@mindspring.com>
Closes #10247
2020-05-06 17:17:38 -07:00
Ryan Moeller
154e48eac9
zdb: Fix ignored zfs_arc_max tuning
Running zdb -l $disk shows a warning that zfs_arc_max is being ignored.
zdb sets zfs_arc_max below zfs_arc_min, which causes the value to be
ignored by arc_tuning_update().

Set zfs_arc_min to the bare minimum in zdb, which is below zfs_arc_max.

Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10269
2020-04-30 17:48:58 -07:00
alex
47c9299fcc
zfs_create: round up volume size to multiple of bs
Round up the volume size requested in `zfs create -V size` to the next
higher multiple of the volblocksize. Updates the man page and adds a
test to verify the new behavior.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reported-by: puffi <puffi@users.noreply.github.com>
Signed-off-by: Alex John <alex@stty.io>
Closes #8541 
Closes #10196
2020-04-24 19:04:34 -07:00
Brian Behlendorf
6de3e59bdd
Fix unitialized variable in zstream redup command
Fix uninitialized variable in `zstream redup` command.  The compiler
may determine the 'stream_offset' variable can be uninitialized
because not all rdt_lookup() exit paths set it.  This should never
happen in practice as documented by the assert, but initialize it
regardless to resolve the warning.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10241
Closes #10244
2020-04-23 15:54:38 -07:00
Matthew Ahrens
196bee4cfd
Remove deduplicated send/receive code
Deduplicated send streams (i.e. `zfs send -D` and `zfs receive` of such
streams) are deprecated.  Deduplicated send streams can be received by
first converting them to non-deduplicated with the `zstream redup`
command.

This commit removes the code for sending and receiving deduplicated send
streams.  `zfs send -D` will now print a warning, ignore the `-D` flag,
and generate a regular (non-deduplicated) send stream.  `zfs receive` of
a deduplicated send stream will print an error message and fail.

The resulting code simplification (especially in the kernel's support
for receiving dedup streams) should help enable future performance
enhancements.

Several new tests are added which leverage `zstream redup`.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Issue #7887
Issue #10117
Issue #10156
Closes #10212
2020-04-23 10:06:57 -07:00
Niklas Haas
a84c92f933
Don't attempt trimming "hole" vdevs
On zpools containing hole vdevs (e.g. removed log devices), the `zpool
trim` (and presumably `zpool initialize`) commands will attempt calling
their respective functions on "hole", which fails, as this is not a real
vdev.

Avoid this by removing HOLE vdevs in zpool_collect_leaves.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Niklas Haas <git@haasn.xyz>
Closes #10227
2020-04-21 09:29:31 -07:00
George Amanakis
9249f1272e
Persistent L2ARC minor fixes
Minor fixes on persistent L2ARC improving code readability and fixing 
a typo in zdb.c when byte-swapping a log block. It also improves the 
pesist_l2arc_007_pos.ksh test by giving it more time to retrieve log 
blocks on the cache device.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Adam D. Moss <c@yotes.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10210
2020-04-17 09:27:40 -07:00
Ryan Moeller
813c8564ee
Fix SC2086 note in zpool.d/smart
./cmd/zpool/zpool.d/smart:78:32:
note: Double quote to prevent globbing and word splitting. [SC2086]

Reported by latest shellcheck on FreeBSD.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10194
2020-04-14 13:18:23 -07:00
Matthew Macy
9f0a21e641
Add FreeBSD support to OpenZFS
Add the FreeBSD platform code to the OpenZFS repository.  As of this
commit the source can be compiled and tested on FreeBSD 11 and 12.
Subsequent commits are now required to compile on FreeBSD and Linux.
Additionally, they must pass the ZFS Test Suite on FreeBSD which is
being run by the CI.  As of this commit 1230 tests pass on FreeBSD
and there are no unexpected failures.

Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #898 
Closes #8987
2020-04-14 11:36:28 -07:00
Joao Carlos Mendes Luis
75c62019f3
Fix allocation errors, detected using ASAN
The test for VDEV_TYPE_INDIRECT is done after a memory allocation, and
could return from function without freeing it.  Since we don't need that
allocation yet, just postpone it.

Add a missing free() when buffer is no longer needed.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: João Carlos Mendes Luís <jonny@jonny.eng.br>
Closes #10193
2020-04-13 10:54:41 -07:00
Brian Behlendorf
8080848254
Minor zstream redup command fixes
* Fix uninitialized variable in `zstream redup` command.  The
  'rdt.ddt_count' variable is uninitialized because it was
  allocated from the stack and not globally.  Initialize it.
  This was reported by gcc when compiling with debugging enabled.

    zstream_redup.c:157:16: error: 'rdt.ddt_count' may be used
    uninitialized in this function [-Werror=maybe-uninitialized]

* Remove the cmd/zstreamdump/.gitignore file.  It's no longer
  needed now that the zstreamdump command is a script.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10192
2020-04-10 21:10:09 -07:00
Matthew Ahrens
c618f87cd2
Add zstream redup command to convert deduplicated send streams
Deduplicated send and receive is deprecated.  To ease migration to the
new dedup-send-less world, the commit adds a `zstream redup` utility to
convert deduplicated send streams to normal streams, so that they can
continue to be received indefinitely.

The new `zstream` command also replaces the functionality of
`zstreamdump`, by way of the `zstream dump` subcommand.  The
`zstreamdump` command is replaced by a shell script which invokes
`zstream dump`.

The way that `zstream redup` works under the hood is that as we read the
send stream, we build up a hash table which maps from `<GUID, object,
offset> -> <file_offset>`.

Whenever we see a WRITE record, we add a new entry to the hash table,
which indicates where in the stream file to find the WRITE record for
this block. (The key is `drr_toguid, drr_object, drr_offset`.)

For entries other than WRITE_BYREF, we pass them through unchanged
(except for the running checksum, which is recalculated).

For WRITE_BYREF records, we change them to WRITE records.  We find the
referenced WRITE record by looking in the hash table (for the record
with key `drr_refguid, drr_refobject, drr_refoffset`), and then reading
the record header and payload from the specified offset in the stream
file.  This is why the stream can not be a pipe.  The found WRITE record
replaces the WRITE_BYREF record, with its `drr_toguid`, `drr_object`,
and `drr_offset` fields changed to be the same as the WRITE_BYREF's
(i.e. we are writing the same logical block, but with the data supplied
by the previous WRITE record).

This algorithm requires memory proportional to the number of WRITE
records (same as `zfs send -D`), but the size per WRITE record is
relatively low (40 bytes, vs. 72 for `zfs send -D`).  A 1TB send stream
with 8KB blocks (`recordsize=8k`) would use around 5GB of RAM to
"redup".

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10124 
Closes #10156
2020-04-10 10:39:55 -07:00