Commit Graph

1411 Commits

Author SHA1 Message Date
Richard Laager
8dda07b33c Reference zfeature.c in a SPA_VERSION comment
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8626
2019-04-16 10:02:19 -07:00
Richard Laager
7698c4eca9 Remove zfs.h comments about GRUB
Nobody is going to be bumping SPA_VERSION again, as OpenZFS has moved on
to feature flags.  Also, there is no requirement to keep GRUB
up-to-date, nor has that been happening.

The ZPL_VERSION could be bumped, but that would likely be handled in a
similar way, by adding filesystem feature flags.  In any event, we do
not need this comment, and we certainly don't need a reference to the
GRUB 0.97 source code in a Solaris tree.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8626
2019-04-16 10:02:14 -07:00
Tomohiro Kusumi
96e51d2773 Sync reserved Illumos ioctl comment with actual number
It's 81 now.

Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes #8598
2019-04-14 11:12:07 -07:00
Tomohiro Kusumi
9a65234c8b Unbreak build on Linux kernel < 3.10
d12614521a("Fixes for procfs files backed by linked lists")
uses PDE_DATA(), but since PDE_DATA() (public interface which
replaced old public interface PDE()) first appeared in upstream
kernel 3.10, it lacks visible local definition for kernel < 3.10.

Move the local PDE_DATA() definition to a ZoL header, to unbreak
build on kernel < 3.10.

--
module/spl/spl-procfs-list.c: In function 'procfs_list_open':
module/spl/spl-procfs-list.c:166: error: implicit declaration of function 'PDE_DATA'
module/spl/spl-procfs-list.c:166: warning: assignment makes pointer from integer without a cast

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Gallagher <john.gallagher@delphix.com>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes #8599
2019-04-08 14:59:24 -07:00
Sara Hartse
a887d653b3 Restrict kstats and print real pointers
There are several places where we use zfs_dbgmsg and %p to
print pointers. In the Linux kernel, these values obfuscated
to prevent information leaks which means the pointers aren't
very useful for debugging crash dumps. We decided to restrict
the permissions of dbgmsg (and some other kstats while we were
at it) and print pointers with %px in zfs_dbgmsg as well as
spl_dumpstack

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Gallagher <john.gallagher@delphix.com>
Signed-off-by: sara hartse <sara.hartse@delphix.com>
Closes #8467 
Closes #8476
2019-04-04 18:57:06 -07:00
Brian Behlendorf
1b939560be
Add TRIM support
UNMAP/TRIM support is a frequently-requested feature to help
prevent performance from degrading on SSDs and on various other
SAN-like storage back-ends.  By issuing UNMAP/TRIM commands for
sectors which are no longer allocated the underlying device can
often more efficiently manage itself.

This TRIM implementation is modeled on the `zpool initialize`
feature which writes a pattern to all unallocated space in the
pool.  The new `zpool trim` command uses the same vdev_xlate()
code to calculate what sectors are unallocated, the same per-
vdev TRIM thread model and locking, and the same basic CLI for
a consistent user experience.  The core difference is that
instead of writing a pattern it will issue UNMAP/TRIM commands
for those extents.

The zio pipeline was updated to accommodate this by adding a new
ZIO_TYPE_TRIM type and associated spa taskq.  This new type makes
is straight forward to add the platform specific TRIM/UNMAP calls
to vdev_disk.c and vdev_file.c.  These new ZIO_TYPE_TRIM zios are
handled largely the same way as ZIO_TYPE_READs or ZIO_TYPE_WRITEs.
This makes it possible to largely avoid changing the pipieline,
one exception is that TRIM zio's may exceed the 16M block size
limit since they contain no data.

In addition to the manual `zpool trim` command, a background
automatic TRIM was added and is controlled by the 'autotrim'
property.  It relies on the exact same infrastructure as the
manual TRIM.  However, instead of relying on the extents in a
metaslab's ms_allocatable range tree, a ms_trim tree is kept
per metaslab.  When 'autotrim=on', ranges added back to the
ms_allocatable tree are also added to the ms_free tree.  The
ms_free tree is then periodically consumed by an autotrim
thread which systematically walks a top level vdev's metaslabs.

Since the automatic TRIM will skip ranges it considers too small
there is value in occasionally running a full `zpool trim`.  This
may occur when the freed blocks are small and not enough time
was allowed to aggregate them.  An automatic TRIM and a manual
`zpool trim` may be run concurrently, in which case the automatic
TRIM will yield to the manual TRIM.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Contributions-by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Contributions-by: Tim Chase <tim@chase2k.com>
Contributions-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8419 
Closes #598
2019-03-29 09:13:20 -07:00
George Wilson
2efea7c82c ZFS Reads may result in unneccesary calls to zil_commit
ZFS supports O_RSYNC for read operations and when specified will ensure
the same level of data integrity that O_DSYNC and O_SYNC provides for
writes. O_RSYNC by itself has no effect so it must be combined with
either O_DSYNC or O_SYNC. However, many platforms don't support O_RSYNC
and have mapped O_SYNC to mean O_RSYNC within ZFS. This is incorrect
and causes unnecessary calls to zil_commit. Only platforms which
support O_RSYNC should implement the zil_commit functionality in the
read code path.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Wilson <george.wilson@delphix.com>
Closes #8523
2019-03-22 13:09:11 -07:00
Olaf Faaland
060f0226e6 MMP interval and fail_intervals in uberblock
When Multihost is enabled, and a pool is imported, uberblock writes
include ub_mmp_delay to allow an importing node to calculate the
duration of an activity test.  This value, is not enough information.

If zfs_multihost_fail_intervals > 0 on the node with the pool imported,
the safe minimum duration of the activity test is well defined, but does
not depend on ub_mmp_delay:

zfs_multihost_fail_intervals * zfs_multihost_interval

and if zfs_multihost_fail_intervals == 0 on that node, there is no such
well defined safe duration, but the importing host cannot tell whether
mmp_delay is high due to I/O delays, or due to a very large
zfs_multihost_interval setting on the host which last imported the pool.
As a result, it may use a far longer period for the activity test than
is necessary.

This patch renames ub_mmp_sequence to ub_mmp_config and uses it to
record the zfs_multihost_interval and zfs_multihost_fail_intervals
values, as well as the mmp sequence.  This allows a shorter activity
test duration to be calculated by the importing host in most situations.
These values are also added to the multihost_history kstat records.

It calculates the activity test duration differently depending on
whether the new fields are present or not; for importing pools with
only ub_mmp_delay, it uses

(zfs_multihost_interval + ub_mmp_delay) * zfs_multihost_import_intervals

Which results in an activity test duration less sensitive to the leaf
count.

In addition, it makes a few other improvements:
* It updates the "sequence" part of ub_mmp_config when MMP writes
  in between syncs occur.  This allows an importing host to detect MMP
  on the remote host sooner, when the pool is idle, as it is not limited
  to the granularity of ub_timestamp (1 second).
* It issues writes immediately when zfs_multihost_interval is changed
  so remote hosts see the updated value as soon as possible.
* It fixes a bug where setting zfs_multihost_fail_intervals = 1 results
  in immediate pool suspension.
* Update tests to verify activity check duration is based on recorded
  tunable values, not tunable values on importing host.
* Update tests to verify the expected number of uberblocks have valid
  MMP fields - fail_intervals, mmp_interval, mmp_seq (sequence number),
  that sequence number is incrementing, and that uberblock values match
  tunable settings.

Reviewed-by: Andreas Dilger <andreas.dilger@whamcloud.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #7842
2019-03-21 12:47:57 -07:00
Tom Caputi
ab7615d92c Multiple DVA Scrubbing Fix
Currently, there is an issue in the sequential scrub code which
prevents self healing from working in some cases. The scrub code
will split up all DVA copies of a bp and issue each of them
separately. The problem is that, since each of the DVAs is no
longer associated with the others, the self healing code doesn't
have the opportunity to repair problems that show up in one of the
DVAs with the data from the others.

This patch fixes this issue by ensuring that all IOs issued by the
sequential scrub code include all DVAs. Initially, only the first
DVA of each is attempted. If an issue arises, the IO is retried
with all available copies, giving the self healing code a chance
to correct the issue.

To test this change, this patch also adds the ability for zinject
to specify individual DVAs to inject read errors into. We then
add a new test case that utilizes this functionality to ensure
scrubs and self-healing reads can handle and transparently fix
issues with individual copies of blocks.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8453
2019-03-15 14:14:31 -07:00
Tom Caputi
f00ab3f22c Detect and prevent mixed raw and non-raw sends
Currently, there is an issue in the raw receive code where
raw receives are allowed to happen on top of previously
non-raw received datasets. This is a problem because the
source-side dataset doesn't know about how the blocks on
the destination were encrypted. As a result, any MAC in
the objset's checksum-of-MACs tree that is a parent of both
blocks encrypted on the source and blocks encrypted by the
destination will be incorrect. This will result in
authentication errors when we decrypt the dataset.

This patch fixes this issue by adding a new check to the
raw receive code. The code now maintains an "IVset guid",
which acts as an identifier for the set of IVs used to
encrypt a given snapshot. When a snapshot is raw received,
the destination snapshot will take this value from the
DRR_BEGIN payload. Non-raw receives and normal "zfs snap"
operations will cause ZFS to generate a new IVset guid.
When a raw incremental stream is received, ZFS will check
that the "from" IVset guid in the stream matches that of
the "from" destination snapshot. If they do not match, the
code will error out the receive, preventing the problem.

This patch requires an on-disk format change to add the
IVset guids to snapshots and bookmarks. As a result, this
patch has errata handling and a tunable to help affected
users resolve the issue with as little interruption as
possible.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8308
2019-03-13 11:00:43 -07:00
Tom Caputi
579ce7c5ae Add bookmark v2 on-disk feature
This patch adds the bookmark v2 feature to the on-disk format. This
feature will be needed for the upcoming redacted sends and for an
upcoming fix that for raw receives. The feature is not currently
used by any code and thus this change is a no-op, aside from the
fact that the user can now enable the feature.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Issue #8308
2019-03-13 10:58:39 -07:00
Tom Caputi
369aa501d1 Fix handling of maxblkid for raw sends
Currently, the receive code can create an unreadable dataset from
a correct raw send stream. This is because it is currently
impossible to set maxblkid to a lower value without freeing the
associated object. This means truncating files on the send side
to a non-0 size could result in corruption. This patch solves this
issue by adding a new 'force' flag to dnode_new_blkid() which will
allow the raw receive code to force the DMU to accept the provided
maxblkid even if it is a lower value than the existing one.

For testing purposes the send_encrypted_files.ksh test has been
extended to include a variety of truncated files and multiple
snapshots. It also now leverages the xattrtest command to help
ensure raw receives correctly handle xattrs.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8168 
Closes #8487
2019-03-13 10:52:01 -07:00
Olaf Faaland
db2af93d72 Increase default zfs_multihost_fail_intervals and import_intervals
By default, when multihost is enabled for a pool, the pool is
suspended if (zfs_multihost_fail_intervals*zfs_multihost_interval) ms
pass without a successful MMP write.  This is the recommended
configuration.

The default value for zfs_multihost_fail_intervals has been 5, and the
default value for zfs_multihost_interval has been 1000, so pool
suspension occurred at 5 seconds.

There have been multiple cases where a single misbehaving device in a
pool triggered a SCSI reset, and all I/O paused for 5-6 seconds.  This
in turn caused MMP to suspend the pool.

In the cases observed, the rest of the devices were healthy and the
pool was otherwise correctly performing I/O.  The reset was handled
correctly by ZFS, and by suspending the pool MMP made replacing the
device more difficult as well as forcing the host to be rebooted.

Increase the default value of zfs_multihost_fail_intervals to 10, so
that MMP tolerates up to 10 seconds of failed MMP writes before
suspending the pool.

Increase the default value of zfs_multihost_import_intervals to 20, to
maintain the 2:1 safety factor.  This results in a force import taking
approximately 20 seconds when MMP is enabled, with default values.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Andreas Dilger <andreas.dilger@whamcloud.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #7709 
Closes #8495
2019-03-13 09:50:48 -07:00
Alek P
4c0883fb4a Avoid retrieving unused snapshot props
This patch modifies the zfs_ioc_snapshot_list_next() ioctl to enable it
to take input parameters that alter the way looping through the list of
snapshots is performed. The idea here is to restrict functions that
throw away some of the snapshots returned by the ioctl to a range of
snapshots that these functions actually use. This improves efficiency
and execution speed for some rollback and send operations.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>
Closes #8077
2019-03-12 13:13:22 -07:00
Olaf Faaland
3d31aad83e MMP writes rotate over leaves
Instead of choosing a leaf vdev quasi-randomly, by starting at the root
vdev and randomly choosing children, rotate over leaves to issue MMP
writes.  This fixes an issue in a pool whose top-level vdevs have
different numbers of leaves.

The issue is that the frequency at which individual leaves are chosen
for MMP writes is based not on the total number of leaves but based on
how many siblings the leaves have.

For example, in a pool like this:

       root-vdev
   +------+---------------+
vdev1                   vdev2
  |                       |
  |                +------+-----+-----+----+
disk1             disk2 disk3 disk4 disk5 disk6

vdev1 and vdev2 will each be chosen 50% of the time.  Every time vdev1
is chosen, disk1 will be chosen.  However, every time vdev2 is chosen,
disk2 is chosen 20% of the time.  As a result, disk1 will be sent 5x as
many MMP writes as disk2.

This may create wear issues in the case of SSDs.  It also reduces the
effectiveness of MMP as it depends on the writes being evenly
distributed for the case where some devices fail or are partitioned.

The new code maintains a list of leaf vdevs in the pool.  MMP records
the last leaf used for an MMP write in mmp->mmp_last_leaf.  To choose
the next leaf, MMP starts at mmp->mmp_last_leaf and traverses the list,
continuing from the head if the tail is reached.  It stops when a
suitable leaf is found or all leaves have been examined.

Added a test to verify MMP write distribution is even.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Kash Pande <kash@tripleback.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #7953
2019-03-12 10:37:06 -07:00
Lorenz Brun
bf90948daf Reorder ZFS ioctls to fix cross-version compatibility
Reorder ZFS ioctls to fix cross-version compatibility.

Reviewed-by: Don Brady <don.brady@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Lorenz Brun <lorenz@dolansoft.org>
Closes #8484
2019-03-09 13:39:31 -08:00
Tony Hutter
becdcec7b9 kernel_fpu fixes
This patch fixes a few issues when detecting which kernel_fpu functions
are available.

- Use kernel_fpu_begin() if it's exported on newer kernels.

- Use ZFS_LINUX_TRY_COMPILE_SYMBOL() to choose the right kernel_fpu
  function when using --enable-linux-builtin.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8259
Closes #8363
2019-03-06 16:03:03 -08:00
Paul Zuchowski
a73e8fdb93 Stack overflow in recursive bpobj_iterate_impl
The function bpobj_iterate_impl overflows the stack when bpobjs
are deeply nested. Rewrite the function to eliminate the recursion.

Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #7674
Closes #7675 
Closes #7908
2019-03-06 09:50:55 -08:00
lidongyang
8d9e51c084 Fix dnode_hold_impl() soft lockup
Soft lockups could happen when multiple threads trying
to get zrl on the same dnode handle in order to allocate
and initialize the dnode marked as DN_SLOT_ALLOCATED.

Don't loop from beginning when we can't get zrl, otherwise
we would increase the zrl refcount and nobody can actually
lock it.

Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Li Dongyang <dongyangli@ddn.com>
Closes #8433
2019-02-22 09:48:37 -08:00
Serapheim Dimitropoulos
928e8ad47d Introduce auxiliary metaslab histograms
This patch introduces 3 new histograms per metaslab. These
histograms track segments that have made it to the metaslab's
space map histogram (and are part of the spacemap) but have
not yet reached the ms_allocatable tree on loaded metaslab's
because these metaslab's are currently syncing and haven't
gone through metaslab_sync_done() yet.

The histograms help when we decide whether to load an unloaded
metaslab in-order to allocate from it. When calculating the
weight of an unloaded metaslab traditionally, we look at the
highest bucket of its spacemap's histogram.  The problem is
that we are not guaranteed to be able to allocated that
segment when we load the metaslab because it may still be at
the freeing, freed, or defer trees. The new histograms are
used when we try to calculate an unloaded metaslab's weight
to deal with this issue by removing segments that have would
not be in the allocatable tree at runtime. Note, that this
method of dealing with this is not completely accurate as
adjacent segments are not always consolidated in the space
map histogram of a metaslab.

In addition and to make things deterministic, we always reset
the weight of unloaded metaslabs based on their space map
weight (instead of doing that on a need basis). Thus, every
time a metaslab is loaded and its weight is reset again (from
the weight based on its space map to the one based on its
allocatable range tree) we expect (and assert) that this
change in weight can only get better if it doesn't stay the
same.

Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8358
2019-02-20 09:59:56 -08:00
Paul Zuchowski
9c5e88b1de zfs should optionally send holds
Add -h switch to zfs send command to send dataset holds. If
holds are present in the stream, zfs receive will create them
on the target dataset, unless the zfs receive -h option is used
to skip receive of holds.

Reviewed-by: Alek Pinchuk <apinchuk@datto.com>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #7513
2019-02-15 12:41:38 -08:00
Tony Hutter
e73ab1b38c Linux 4.20 compat: Fix VERIFY(RW_READ_HELD(&hash->mh_contents))
The 4.20 kernel changed the meaning of the rw_semaphore.owner bits,
causing an assertion when loading the module under the 4.20 kernel.
This patch fixes the issue.

Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8360 
Closes #8389
2019-02-15 12:37:20 -08:00
Alek P
dcec0a12c8 port async unlinked drain from illumos-nexenta
This patch is an async implementation of the existing sync
zfs_unlinked_drain() function. This function is called at mount time and
is responsible for freeing znodes that we didn't get to freeing before.
We don't have to hold mounting of the dataset until the unlinked list is
fully drained as is done now. Since we can process the unlinked set
asynchronously this results in a better user experience when mounting a
dataset with entries in the unlinked set.

Reviewed by: Jorgen Lundman <lundman@lundman.net>
Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>
Closes #8142
2019-02-12 10:41:15 -08:00
Serapheim Dimitropoulos
425d3237ee Get rid of space_map_update() for ms_synced_length
Initially, metaslabs and space maps used to be the same thing
in ZFS. Later, we started differentiating them by referring
to the space map as the on-disk state of the metaslab, making
the metaslab a higher-level concept that is metadata that deals
with space accounting. Today we've managed to split that code
furthermore, with the space map being its own on-disk data
structure used in areas of ZFS besides metaslabs (e.g. the
vdev-wide space maps used for zpool checkpoint or vdev removal
features).

This patch refactors the space map code to further split the
space map code from the metaslab code. It does so by getting
rid of the idea that the space map can have a different in-core
and on-disk length (sm_length vs smp_length) which is something
that is only used for the metaslab code, and other consumers
of space maps just have to deal with. Instead, this patch
introduces changes that move the old in-core length of the
metaslab's space map to the metaslab structure itself (see
ms_synced_length field) while making the space map code only
care about the actual space map's length on-disk.

The result of this is that space map consumers no longer have
to deal with syncing two different lengths for the same
structure (e.g. space_map_update() goes away) while metaslab
specific behavior stays within the metaslab code. Specifically,
the ms_synced_length field keeps track of the amount of data
metaslab_load() can read from the metaslab's space map while
working concurrently with metaslab_sync() that may be
appending to that same space map.

As a side note, the patch also adds a few comments around
the metaslab code documenting some assumptions and expected
behavior.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8328
2019-02-12 10:38:11 -08:00
loli10K
d8d418ff0c ZVOLs should not be allowed to have children
zfs create, receive and rename can bypass this hierarchy rule. Update
both userland and kernel module to prevent this issue and use pyzfs
unit tests to exercise the ioctls directly.

Note: this commit slightly changes zfs_ioc_create() ABI. This allow to
differentiate a generic error (EINVAL) from the specific case where we
tried to create a dataset below a ZVOL (ZFS_ERR_WRONG_PARENT).

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
2019-02-08 15:44:15 -08:00
Tony Hutter
0c593296e9 Linux 5.0 compat: Disable vector instructions on 5.0+ kernels
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8259
2019-01-28 10:11:45 -08:00
Tony Hutter
031cea17a3 Linux 5.0 compat: Use totalram_pages()
totalram_pages() was converted to an atomic variable in 5.0:

https://patchwork.kernel.org/patch/10652795/

Its value should now be read though the totalram_pages() helper
function.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8263
2019-01-28 10:11:14 -08:00
Tony Hutter
77e50c3070 Linux 5.0 compat: access_ok() drops 'type' parameter
access_ok no longer needs a 'type' parameter in the 5.0 kernel.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8261
2019-01-28 10:11:10 -08:00
Tony Hutter
5cb46f6a66 Linux 4.18 compat: Use ktime_get_coarse_real_ts64()
Newer kernels remove current_kernel_time64().  Use
ktime_get_coarse_real_ts64() in its place.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8258
2019-01-28 10:11:03 -08:00
Serapheim Dimitropoulos
df72b8bebe Rename range_tree_verify to range_tree_verify_not_present
The range_tree_verify function looks for a segment in a
range tree and panics if the segment is present on the
tree. This patch gives the function a more descriptive
name.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8327
2019-01-25 09:51:24 -08:00
Serapheim Dimitropoulos
b194fab0fb Factor metaslab_load_wait() in metaslab_load()
Most callers that need to operate on a loaded metaslab, always
call metaslab_load_wait() before loading the metaslab just in
case someone else is already doing the work.

Factoring metaslab_load_wait() within metaslab_load() makes the
later more robust, as callers won't have to do the load-wait
check explicitly every time they need to load a metaslab.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8290
2019-01-18 11:10:32 -08:00
Serapheim Dimitropoulos
1a759200e5 Document guidelines for usage of zfs_dbgmsg
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8299
2019-01-18 10:16:56 -08:00
Tom Caputi
305781da4b Fix error handling incallers of dbuf_hold_level()
Currently, the functions dbuf_prefetch_indirect_done() and
dmu_assign_arcbuf_by_dnode() assume that dbuf_hold_level() cannot
fail. In the event of an error the former will cause a NULL pointer
dereference and the later will trigger a VERIFY. This patch adds
error handling to these functions and their callers where necessary.

Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8291
2019-01-17 15:47:08 -08:00
Serapheim Dimitropoulos
75058f3303 Remove unused vdev_t fields
The following fields from the vdev_t struct are not used anywhere.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8285
2019-01-17 15:41:12 -08:00
Serapheim Dimitropoulos
61c3391acc Serialize ZTHR operations to eliminate races
Adds a new lock for serializing operations on zthrs.
The commit also includes some code cleanup and
refactoring.

Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8229
2019-01-13 10:09:46 -08:00
Brian Behlendorf
6955b40138
Provide more flexible object allocation interface
Object allocation performance can be improved for complex operations
by providing an interface which returns the newly allocated dnode.
This allows the caller to immediately use the dnode without incurring
the expense of looking up the dnode by object number.

The functions dmu_object_alloc_hold(), zap_create_hold(), and
dmu_bonus_hold_by_dnode() were added for this purpose.

The zap_create_* functions have been updated to take advantage of
this new functionality.  The dmu_bonus_hold_impl() function should
really have never been included in sys/dmu.h and was removed.
It's sole caller was converted to use dmu_bonus_hold_by_dnode().

The new symbols have been exported for use by Lustre.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8015
2019-01-10 14:37:43 -08:00
George Wilson
c10d37dd9f zfs initialize performance enhancements
PROBLEM
========

When invoking "zpool initialize" on a pool the command will
create a thread to initialize each disk. Unfortunately, it does
this serially across many transaction groups which can result
in commands taking a long time to return to the user and may
appear hung. The same thing is true when trying to suspend/cancel
the operation.

SOLUTION
=========

This change refactors the way we invoke the initialize interface
to ensure we can start or stop the intialization in just a few
transaction groups.

When stopping or cancelling a vdev initialization perform it
in two phases.  First signal each vdev initialization thread
that it should exit, then after all threads have been signaled
wait for them to exit.

On a pool with 40 leaf vdevs this reduces the vdev initialize
stop/cancel time from ~10 minutes to under a second.  The reason
for this is spa_vdev_initialize() no longer needs to wait on
multiple full TXGs per leaf vdev being stopped.

This commit additionally adds some missing checks for the passed
"initialize_vdevs" input nvlist.  The contents of the user provided
input "initialize_vdevs" nvlist must be validated to ensure all
values are uint64s.  This is done in zfs_ioc_pool_initialize() in
order to keep all of these checks in a single location.

Updated the innvl and outnvl comments to match the formatting used
for all other new sytle ioctls.

Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Wilson <george.wilson@delphix.com>
Closes #8230
2019-01-07 11:03:08 -08:00
George Wilson
619f097693 OpenZFS 9102 - zfs should be able to initialize storage devices
PROBLEM
========

The first access to a block incurs a performance penalty on some platforms
(e.g. AWS's EBS, VMware VMDKs). Therefore we recommend that volumes are
"thick provisioned", where supported by the platform (VMware). This can
create a large delay in getting a new virtual machines up and running (or
adding storage to an existing Engine). If the thick provision step is
omitted, write performance will be suboptimal until all blocks on the LUN
have been written.

SOLUTION
=========

This feature introduces a way to 'initialize' the disks at install or in the
background to make sure we don't incur this first read penalty.

When an entire LUN is added to ZFS, we make all space available immediately,
and allow ZFS to find unallocated space and zero it out. This works with
concurrent writes to arbitrary offsets, ensuring that we don't zero out
something that has been (or is in the middle of being) written. This scheme
can also be applied to existing pools (affecting only free regions on the
vdev). Detailed design:
        - new subcommand:zpool initialize [-cs] <pool> [<vdev> ...]
                - start, suspend, or cancel initialization
        - Creates new open-context thread for each vdev
        - Thread iterates through all metaslabs in this vdev
        - Each metaslab:
                - select a metaslab
                - load the metaslab
                - mark the metaslab as being zeroed
                - walk all free ranges within that metaslab and translate
                  them to ranges on the leaf vdev
                - issue a "zeroing" I/O on the leaf vdev that corresponds to
                  a free range on the metaslab we're working on
                - continue until all free ranges for this metaslab have been
                  "zeroed"
                - reset/unmark the metaslab being zeroed
                - if more metaslabs exist, then repeat above tasks.
                - if no more metaslabs, then we're done.

        - progress for the initialization is stored on-disk in the vdev’s
          leaf zap object. The following information is stored:
                - the last offset that has been initialized
                - the state of the initialization process (i.e. active,
                  suspended, or canceled)
                - the start time for the initialization

        - progress is reported via the zpool status command and shows
          information for each of the vdevs that are initializing

Porting notes:
- Added zfs_initialize_value module parameter to set the pattern
  written by "zpool initialize".
- Added zfs_vdev_{initializing,removal}_{min,max}_active module options.

Authored by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Wren Kennedy <john.kennedy@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: loli10K <ezomori.nozomu@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Richard Lowe <richlowe@richlowe.net>
Signed-off-by: Tim Chase <tim@chase2k.com>
Ported-by: Tim Chase <tim@chase2k.com>

OpenZFS-issue: https://www.illumos.org/issues/9102
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c3963210eb
Closes #8230
2019-01-07 10:37:26 -08:00
bunder2015
5365b0747a Add missing MMP status code to libzfs_status
When MMP was merged the status codes in libzfs_status were not
updated to add the status code for ZPOOL_STATUS_IO_FAILURE_MMP.  This
commit corrects this and adds comments to help keep track of which
code is used for which status.

Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: bunder2015 <omfgbunder@gmail.com>
Closes #8148
Closes #8222
2019-01-03 12:15:46 -08:00
Brad Lewis
3ec34e5527 OpenZFS 9284 - arc_reclaim_thread has 2 jobs
Following the fix for 9018 (Replace kmem_cache_reap_now() with
kmem_cache_reap_soon), the arc_reclaim_thread() no longer blocks
while reaping.  However, the code is still confusing and error-prone,
because this thread has two responsibilities.  We should instead
separate this into two threads each with their own responsibility:

 1. keep `arc_size` under `arc_c`, by calling `arc_adjust()`, which
    improves `arc_is_overflowing()`

 2. keep enough free memory in the system, by calling
    `arc_kmem_reap_now()` plus `arc_shrink()`, which improves
    `arc_available_memory()`.

Furthermore, we can use the zthr infrastructure to separate the
"should we do something" from "do it" parts of the logic, and
normalize the start up / shut down of the threads.

Authored by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Dan McDonald <danmcd@joyent.com>
Reviewed by: Tim Kordas <tim.kordas@joyent.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by:  Brad Lewis <brad.lewis@delphix.com>
Signed-off-by: Brad Lewis <brad.lewis@delphix.com>

OpenZFS-issue: https://www.illumos.org/issues/9284
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/de753e34f9
Closes #8165
2018-12-26 13:22:28 -08:00
Andriy Gapon
dc1c630b8a OpenZFS 9630 - add lzc_rename and lzc_destroy to libzfs_core
Porting Notes:
* Additional changes to recv_rename_impl() were required due to
  encryption code not being merged in OpenZFS yet.
* libzfs_core python bindings (pyzfs) were updated to fully support
  both lzc_rename() and lzc_destroy()

Authored by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: loli10K <ezomori.nozomu@gmail.com>

OpenZFS-issue: https://www.illumos.org/issues/9630
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/049ba63
Closes #8207
2018-12-14 09:49:45 -08:00
Prakash Surya
900d09b285 OpenZFS 9962 - zil_commit should omit cache thrash
As a result of the changes made in 8585, it's possible for an excessive
amount of vdev flush commands to be issued under some workloads.

Specifically, when the workload consists of mostly async write activity,
interspersed with some sync write and/or fsync activity, we can end up
issuing more flush commands to the underlying storage than is actually
necessary. As a result of these flush commands, the write latency and
overall throughput of the pool can be poorly impacted (latency
increases, throughput decreases).

Currently, any time an lwb completes, the vdev(s) written to as a result
of that lwb will be issued a flush command. The intenion is so the data
written to that vdev is on stable storage, prior to communicating to any
waiting threads that their data is safe on disk.

The problem with this scheme, is that sometimes an lwb will not have any
threads waiting for it to complete. This can occur when there's async
activity that gets "converted" to sync requests, as a result of calling
the zil_async_to_sync() function via zil_commit_impl(). When this
occurs, the current code may issue many lwbs that don't have waiters
associated with them, resulting in many flush commands, potentially to
the same vdev(s).

For example, given a pool with a single vdev, and a single fsync() call
that results in 10 lwbs being written out (e.g. due to other async
writes), that will result in 10 flush commands to that single vdev (a
flush issued after each lwb write completes). Ideally, we'd only issue a
single flush command to that vdev, after all 10 lwb writes completed.

Further, and most important as it pertains to this change, since the
flush commands are often very impactful to the performance of the pool's
underlying storage, unnecessarily issuing these flush commands can
poorly impact the performance of the lwb writes themselves. Thus, we
need to avoid issuing flush commands when possible, in order to acheive
the best possible performance out of the pool's underlying storage.

This change attempts to address this problem by changing the ZIL's logic
to only issue a vdev flush command when it detects an lwb that has a
thread waiting for it to complete. When an lwb does not have threads
waiting for it, the responsibility of issuing the flush command to the
vdevs involved with that lwb's write is passed on to the "next" lwb.
It's only once a write for an lwb with waiters completes, do we issue
the vdev flush command(s). As a result, now when we issue the flush(s),
we will issue them to the vdevs involved with that specific lwb's write,
but potentially also to vdevs involved with "previous" lwb writes (i.e.
if the previous lwbs did not have waiters associated with them).

Thus, in our prior example with 10 lwbs, it's only once the last lwb
completes (which will be the lwb containing the waiter for the thread
that called fsync) will we issue the vdev flush command; all of the
other lwbs will find they have no waiters, so they'll pass the
responsibility of the flush to the "next" lwb (until reaching the last
lwb that has the waiter).

Porting Notes:
* Reconciled conflicts with the fastwrite feature.

Authored by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Patrick Mooney <patrick.mooney@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Approved by: Joshua M. Clulow <josh@sysmgr.org>
Ported-by: Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/9962
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/545190c6
Closes #8188
2018-12-07 11:09:42 -08:00
Sebastien Roy
a10d50f999 OpenZFS 8115 - parallel zfs mount
Porting Notes:
* Use thread pools (tpool) API instead of introducing taskq interfaces
  to libzfs.
* Use pthread_mutext for locks as mutex_t isn't available.
* Ignore alternative libshare initialization since OpenZFS-7955 is
  not present on zfsonlinux.

Authored by: Sebastien Roy <seb@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Prashanth Sreenivasa <pks@delphix.com>
Authored by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Matt Ahrens <mahrens@delphix.com>
Ported-by: Don Brady <don.brady@delphix.com>

OpenZFS-issue: https://www.illumos.org/issues/8115
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/a3f0e2b569
Closes #8092
2018-11-15 11:33:58 -08:00
loli10K
d48091de81 zed: detect and offline physically removed devices
This commit adds a new test case to the ZFS Test Suite to verify ZED
can detect when a device is physically removed from a running system:
the device will be offlined if a spare is not available in the pool.

We implement this by using the existing libudev functionality and
without relying solely on the FM kernel module capabilities which have
been observed to be unreliable with some kernels.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Don Brady <don.brady@delphix.com>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #1537
Closes #7926
2018-11-09 11:17:24 -08:00
Tony Hutter
ad796b8a3b Add zpool status -s (slow I/Os) and -p (parseable)
This patch adds a new slow I/Os (-s) column to zpool status to show the
number of VDEV slow I/Os. This is the number of I/Os that didn't
complete in zio_slow_io_ms milliseconds. It also adds a new parsable
(-p) flag to display exact values.

 	NAME         STATE     READ WRITE CKSUM  SLOW
 	testpool     ONLINE       0     0     0     -
	  mirror-0   ONLINE       0     0     0     -
 	    loop0    ONLINE       0     0     0    20
 	    loop1    ONLINE       0     0     0     0

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #7756
Closes #6885
2018-11-08 16:47:24 -08:00
Don Brady
95692927f2 Fix libudev dependency in libzutil
ZFS should be able to build without libudev installed. The recent
change for libzutil inadvertently broke that.  Make the libudev code
conditional in zutil_import.c to resolve the build failure.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes #8097
2018-11-06 17:47:52 -08:00
Don Brady
e89f1295d4 Add libzutil for libzfs or libzpool consumers
Adds a libzutil for utility functions that are common to libzfs and
libzpool consumers (most of what was in libzfs_import.c).  This
removes the need for utilities to link against both libzpool and
libzfs.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes #8050
2018-11-05 11:22:33 -08:00
Brian Behlendorf
82c0a050fc
Linux 4.20 compat: current_kernel_time()
Commit torvalds/linux@976516404 removed the current_kernel_time()
function (and several others).  All callers are expected to use
current_kernel_time64().  Update the gethrestime_sec() wrapper
accordingly.

Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8074
2018-10-31 11:50:42 -05:00
Brian Behlendorf
b3d7725c94
Remove zfs_gitrev.h
This generated file was accidentally included in previous commit,
80a91e7, and should not be included in the repository.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed by: Don Brady <don.brady@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8054
2018-10-24 14:48:14 -07:00
Tom Caputi
ab4c009e3d Fix dbgmsg printing in ztest and zdb
This patch resolves a problem where the -G option in both zdb and
ztest would cause the code to call __dprintf() to print zfs_dbgmsg
output. This function was not properly wired to add messages to the
dbgmsg log as it is in userspace and so the messages were simply
dropped. This patch also tries to add some degree of distinction to
dprintf() (which now prints directly to stdout) and zfs_dbgmsg()
(which adds messages to an internal list that can be dumped with
zfs_dbgmsg_print()).

In addition, this patch corrects an issue where ztest used a global
variable to decide whether to dump the dbgmsg buffer on a crash.
This did not work because ztest spins up more instances of itself
using execv(), which did not copy the global variable to the new
process. The option has been moved to the ztest_shared_opts_t
which already exists for interprocess communication.

This patch also changes zfs_dbgmsg_print() to use write() calls
instead of printf() so that it will not fail when used in a signal
handler.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8010
2018-10-24 14:36:50 -07:00