* Add a high level comment.
* Avoid unnecessary line wrapping.
* Simplify size accounting logic.
* Eliminate unnecessary buffer on the stack.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
This makes the header print before the sleep as well, which is fine.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
In zfs_send_progress, initialize \*bytes_written and \*blocks_visited
in case we have to return early due to ioctl failure.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
* Don't bother building a debug nvlist if we can't return it.
* Save errno after ioctl failure in case snprintf clobbers it.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
* Capitalize and punctuate complete sentences in comments.
* Separate out a group of locals to add a comment on their purpose.
* Remove unnecessary line wrapping.
* Make it clear that dds_origin is a string by using explicit character
comparison to check for an empty string, rather than implictly
treating it as a boolean.
* Reorganize manipulation of props and holds nvlists to improve
clarity.
* There's no need to initialize the snapname buffer with zeros, we're
immediately overwriting it.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
* Add a high level comment.
* Move locals closer to point of use.
* Use fnv* routines rather than explicit verification of success.
* Factor out duplicated code by introducing isspacelimit to clarify
behavior.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
* Add a high level comment.
* Use local variables to reduce line wrapping.
* Remove extra braces and insert space for clarity.
* Assert precondition that the dataset name contains '@' for sanity.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
There is no need to allocate a holds nvlist. lzc_get_holds does that
for us.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
avl_add does avl_find internally, then avl_insert. We're already doing
the avl_find, so using avl_insert directly avoids repeating the search.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
De-clutter the clode and make it clear the guid is only used here.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
We won't be passing a negative value here, so make it clear.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#12967
This reverts commit f6a0dac84a.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#12938
Any error from lzc_send_redacted is overwritten by the error of
send_conclusion_record; skip writing the conclusion record if there
was an earlier error.
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Philipp Riederer <philipp@riederer.email>
Closes#12766
If the fields to be listed and sorted by are constrained
to those populated by dsl_dataset_fast_stat(), then
zfs list is much faster, as it does not need to open each
objset and reads its properties.
A previous optimization by Pawel Dawidek
(0cee24064a) took advantage
of this to make listing snapshot names sorted only by name
much faster.
However, it was limited to `-o name -s name`, this work
extends this optimization to work with:
- name
- guid
- createtxg
- numclones
- inconsistent
- redacted
- origin
and could be further extended to any other properties
supported by dsl_dataset_fast_stat() or similar, that do
not require extra locking or reading from disk.
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Pawel Jakub Dawidek <pawel@dawidek.net>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#11080
"has unsupported feature: [number]" seems reasonable when we can't
know what the problem was, but with the send -D removal, we know
what it was, and can explicitly tell people "don't do that; try
this if you must".
So let's.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes#12708
It turns out, userland is much more happy with aliased property
names than the kernel is.
So let's normalize those to the expected names before we pass
them off.
Added a test case hacked up from the other recv -o/-x test that fails
on unpatched git and passes here.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes#12607Closes#12609
zfs send -R -i snap1 pool/ds@snap1 is an invalid invocation of zfs send
because the incremental source and target snapshots are the same. We
have an error message for this condition, but we don't make it there
because of a failed assert while iterating through the dataset's
snapshots.
Check for NULL to avoid the assert so we can make it to the error
message.
Test this form of invalid send invocation in rsend tests. Fix the
rsend_016_neg test while here: log_neg itself doesn't fail the test,
and writing to /dev/null is not supported on all Linux kernels.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11121Closes#12533
As of the Linux 5.9 kernel a fallthrough macro has been added which
should be used to anotate all intentional fallthrough paths. Once
all of the kernel code paths have been updated to use fallthrough
the -Wimplicit-fallthrough option will because the default. To
avoid warnings in the OpenZFS code base when this happens apply
the fallthrough macro.
Additional reading: https://lwn.net/Articles/794944/
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#12441
Possibly required in the past, but is currently fills no purpose.
Ordinarily such tiny cleanup is not generally worth it, however
on the macOS port, in a future commit, we do unspeakable things to the
"fd" for send/recv, and it would be easier to only have to deal with
one "fd" instead of two.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes#12404
A couple flags weren't being copied in the case where we're doing size
estimation on a resume.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes: #12266
Starting in Linux 5.10, trying to write to /dev/{null,zero} errors out.
Prefer to inform people when this happens rather than hoping they guess
what's wrong.
Reviewed-by: Antonio Russo <aerusso@aerusso.net>
Reviewed-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes: #11991
While OpenZFS does permit breaking changes to the libzfs API, we should
avoid these changes when reasonably possible, and take steps to mitigate
the impact to consumers when changes are necessary.
Commit e4288a8397 made a libzfs API change that is especially
difficult for consumers because there is no change to the function
signatures, only to their behavior. Therefore, consumers can't notice
that there was a change at compile time. Also, the API change was
incompletely and incorrectly documented.
The commit message mentions `zfs_get_prop()` [sic], but all callers of
`get_numeric_property()` are impacted: `zfs_prop_get()`,
`zfs_prop_get_numeric()`, and `zfs_prop_get_int()`.
`zfs_prop_get_int()` always calls `get_numeric_property(src=NULL)`, so
it assumes that the filesystem is not mounted. This means that e.g.
`zfs_prop_get_int(ZFS_PROP_MOUNTED)` always returns 0.
The documentation says that to preserve the previous behavior, callers
should initialize `*src=ZPROP_SRC_NONE`, and some callers were changed
to do that. However, the existing behavior is actually preserved by
initializing `*src=ZPROP_SRC_ALL`, not `NONE`.
The code comment above `zfs_prop_get()` says, "src: ... NULL will be
treated as ZPROP_SRC_ALL.". However, the code actually treats NULL as
ZPROP_SRC_NONE. i.e. `zfs_prop_get(src=NULL)` assumes that the
filesystem is not mounted.
There are several existing calls which use `src=NULL` which are impacted
by the API change, most noticeably those used by `zfs list`, which now
assumes that filesystems are not mounted. For example,
`zfs list -o name,mounted` previously indicated whether a filesystem was
mounted or not, but now it always (incorrectly) indicates that the
filesystem is not mounted (`MOUNTED: no`). Similarly, properties that
are set at mount time are ignored. E.g. `zfs list -o name,atime` may
display an incorrect value if it was set at mount time.
To address these problems, this commit reverts commit e4288a8397bb1f:
"zfs get: don't lookup mount options when using "-s local""
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#11999
Looking up mount options can be very expensive on servers with many
mounted file systems. When doing "zfs get" with any "-s" option that
does not include "temporary", the mount list will never be used. This
commit optimizes for that case.
This is a breaking commit for libzfs! Callers of zfs_get_prop are now
required to initialize src. To preserve existing behavior, they should
initialize it to ZPROP_SRC_NONE.
Sponsored by: Axcient
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11955
Receiving datasets while blanket inheriting properties like zfs
receive -x mountpoint can generally be desirable, e.g. to avoid
unexpected mounts on backup hosts.
Currently this will fail to receive zvols due to the mountpoint
property being applicable to filesystems only. This limitation
currently requires operators to special-case their minds and tools
for zvols.
This change gets rid of this limitation for inherit (-x) by
Spiting up the dataset type handling: Warnings for inheriting (-x),
errors for overriding (-o).
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: InsanePrawn <insane.prawny@gmail.com>
Closes#11416Closes#11840Closes#11864
zfs recv -n does not report some errors it could. The code to bail
out of the receive if in dry-run mode came a little early, skipping
validation of cmdprops (recv -x and -o) among others. Move the
check down to enable these additional checks.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: InsanePrawn <insane.prawny@gmail.com>
Closes#11862
As found by
git grep -E '(open|setmntent|pipe2?)\(' |
grep -vE '((zfs|zpool)_|fd|dl|lzc_re|pidfile_|g_)open\('
FreeBSD's pidfile_open() says nothing about the flags of the files it
opens, but we can't do anything about it anyway; the implementation does
open all files with O_CLOEXEC
Consider this output with zpool.d/media appended with
"pid=$$; (ls -l /proc/$pid/fd > /dev/tty)":
$ /sbin/zpool iostat -vc media
lrwx------ 0 -> /dev/pts/0
l-wx------ 1 -> 'pipe:[3278500]'
l-wx------ 2 -> /dev/null
lrwx------ 3 -> /dev/zfs
lr-x------ 4 -> /proc/31895/mounts
lrwx------ 5 -> /dev/zfs
lr-x------ 10 -> /usr/lib/zfs-linux/zpool.d/media
vs
$ ./zpool iostat -vc vendor,upath,iostat,media
lrwx------ 0 -> /dev/pts/0
l-wx------ 1 -> 'pipe:[3279887]'
l-wx------ 2 -> /dev/null
lr-x------ 10 -> /usr/lib/zfs-linux/zpool.d/media
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes#11866
A tentative implementation and discussion was done in #5285.
According to it a send --skip-missing|-s flag has been added.
In a replication stream, when there are snapshots missing in
the hierarchy, if -s is provided print a warning and ignore
dataset (and its children) instead of throwing an error
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pablo Correa Gómez <ablocorrea@hotmail.com>
Closes#11710
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Closes#11775
The behavior of a NULL fromsnap was inadvertently changed for a doall
send when the send/recv logic in libzfs was updated. Restore the
previous behavior by correcting send_iterate_snap() to include all
the snapshots in the nvlist for this case.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Cedric Maunoury <cedric.maunoury@gmail.com>
Closes#11608
Use verified variants of nvlist/nvpair functions where applicable.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11460
fixup of 196bee4
On gcc (GCC) 9.2.1 20190827 (Red Hat 9.2.1-1), the code removed
caused `-Wmaybe-uninitialized` errors.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Christian Schwarz <me@cschwarz.com>
Closes#11021
When resuming an interrupted ZFS send stream that creates a new dataset
with the same name as an existing dataset, if the existing dataset is
accessed after the failed receive, then after the subsequent successful
receive it will return EIO. This happens because nothing mounts the new
dataset, leaving the old, no longer valid dataset still mounted.
This commit fixes zfs receive to always unmount and remount the
destination, regardless of whether the stream is a new stream or a
resumed stream.
Sponsored by: Axcient
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alan Somers <asomers@gmail.com>
External-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=249579Closes#10995Closes#10999
Originally we asserted that all reads are less than SPA_MAXBLOCKSIZE
However, nvlists are not ZFS records, and are not limited to
SPA_MAXBLOCKSIZE.
Add a new environment variable, ZFS_SENDRECV_MAX_NVLIST, to allow the
user to specify the maximum size of the nvlist that can be sent or
received.
Default value: 4 * SPA_MAXBLOCKSIZE (64 MB)
Modify libzfs send routines to return a useful error if the send stream
will generate an nvlist that is beyond the maximum size.
Modify libzfs recv routines to add an explicit error message if the
nvlist is too large, rather than abort()ing.
Move the change the assert() to only trigger on data records
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#9616
The clang version 8.0.1 shipped in FreeBSD 12.1-RELEASE also oddly
throws a warning that is treated as an error on the initialization of
the zc struct in zpool_nextboot.
The zpool_nextboot code from FreeBSD was not updated to use zfs_ioctl.
Switch ioctl to zfs_ioctl in and use {"\0"} to initialize the struct.
Do a consistency pass for zfs_cmd_t initialization.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10539
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
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#6224Closes#10383
Given the following test program:
#include <time.h>
#include <stdio.h>
#include <stdint.h>
int main() {
printf("time_t: %d\n", sizeof(time_t));
printf("long: %d\n", sizeof(long));
printf("long long: %d\n", sizeof(long long));
}
These are output on various x86 architectures:
x32$ time_t: 8
x32$ long: 4
x32$ long long: 8
amd64$ time_t: 8
amd64$ long: 8
amd64$ long long: 8
i386$ time_t: 4
i386$ long: 4
i386$ long long: 8
Therefore code using "%l[du]" to format time_ts produced warnings on x32
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@gmail.com>
Closes#10357Closes#844
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 #10156Closes#10212
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#10124Closes#10156
Dedup send can only deduplicate over the set of blocks in the send
command being invoked, and it does not take advantage of the dedup table
to do so. This is a very common misconception among not only users, but
developers, and makes the feature seem more useful than it is. As a
result, many users are using the feature but not getting any benefit
from it.
Dedup send requires a nontrivial expenditure of memory and CPU to
operate, especially if the dataset(s) being sent is (are) not already
using a dedup-strength checksum.
Dedup send adds developer burden. It expands the test matrix when
developing new features, causing bugs in released code, and delaying
development efforts by forcing more testing to be done.
As a result, we are deprecating the use of `zfs send -D` and receiving
of such streams. This change adds a warning to the man page, and also
prints the warning whenever dedup send or receive are used.
In a future release, we plan to:
1. remove the kernel code for generating deduplicated streams
2. make `zfs send -D` generate regular, non-deduplicated streams
3. remove the kernel code for receiving deduplicated streams
4. make `zfs receive` of deduplicated streams process them in userland
to "re-duplicate" them, so that they can still be received.
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#7887Closes#10117