This is primarily of use when a pool has lost its disk, while the user
doesn't care about any pending (or otherwise) transactions.
Implement various control methods to make this feasible:
- txg_wait can now take a NOSUSPEND flag, in which case the caller will
be alerted if their txg can't be committed. This is primarily of
interest for callers that would normally pass TXG_WAIT, but don't want
to wait if the pool becomes suspended, which allows unwinding in some
cases, specifically when one is attempting a non-forced export.
Without this, the non-forced export would preclude a forced export
by virtue of holding the namespace lock indefinitely.
- txg_wait also returns failure for TXG_WAIT users if a pool is actually
being force exported. Adjust most callers to tolerate this.
- spa_config_enter_flags now takes a NOSUSPEND flag to the same effect.
- DMU objset initiator which may be set on an objset being forcibly
exported / unmounted.
- SPA export initiator may be set on a pool being forcibly exported.
- DMU send/recv now use an interruption mechanism which relies on the
SPA export initiator being able to enumerate datasets and closing any
send/recv streams, causing their EINTR paths to be invoked.
- ZIO now has a cancel entry point, which tells all suspended zios to
fail, and which suppresses the failures for non-CANFAIL users.
- metaslab, etc. cleanup, which consists of simply throwing away any
changes that were not able to be synced out.
- Linux specific: introduce a new tunable,
zfs_forced_export_unmount_enabled, which allows the filesystem to
remain in a modified 'unmounted' state upon exiting zpl_umount_begin,
to achieve parity with FreeBSD and illumos,
which have VFS-level support for yanking filesystems out from under
users. However, this only helps when the user is actively performing
I/O, while not sitting on the filesystem. In particular, this allows
test #3 below to pass on Linux.
- Add basic logic to zpool to indicate a force-exporting pool, instead
of crashing due to lack of config, etc.
Add tests which cover the basic use cases:
- Force export while a send is in progress
- Force export while a recv is in progress
- Force export while POSIX I/O is in progress
This change modifies the libzfs ABI:
- New ZPOOL_STATUS_FORCE_EXPORTING zpool_status_t enum value.
- New field libzfs_force_export for libzfs_handle.
Signed-off-by: Will Andrews <will@firepipe.net>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Mariusz Zaborski <mariusz.zaborski@klarasystems.com>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Sponsored-by: Klara, Inc.
Sponsored-by: Catalogics, Inc.
Sponsored-by: Wasabi Technology, Inc.
Closes#3461
(cherry picked from commit 852e633772217d779a63e8c46fe3c5f81dd8960e)
`getfsstat(2)` is used to retrieve the list of mounted file systems,
which libzfs uses when fetching properties like mountpoint, atime,
setuid, etc. The `mode` parameter may be `MNT_NOWAIT`, which uses
information in the VFS's cache, or `MNT_WAIT`, which effectively does a
`statfs` on every single mounted file system in order to fetch the most
up-to-date information. As far as I can tell, the only fields that
libzfs cares about are the filesystem's name, mountpoint, fstypename,
and mount flags. Those things are always updated on mount and unmount,
so they will always be accurate in the VFS's mount cache except in two
circumstances:
1) When a file system is busy unmounting
2) When a ZFS file system changes the value of a mount-overridable
property like atime or setuid, but doesn't remount the file system.
Right now that only happens when the property is changed by an
unprivileged user who has delegated authority to change the property
but not to mount the dataset. But perhaps libzfs could choose to do
it for other reasons in the future.
Switching to `MNT_NOWAIT` will greatly improve speed with no downside,
as long as we explicitly update the mount cache whenever we change a
mount-overridable property.
For comparison, Illumos gets this information using the native
`getmntany` and `getmntent` functions, which also use cached
information. The illumos function that would refresh the cache,
`resetmnttab`, is never called by libzfs.
And on GNU/Linux, `getmntany` and `getmntent` don't even communicate
with the kernel directly. They simply parse the file they are given,
which is usually /etc/mtab or /proc/mounts. Perhaps the implementation
of /proc/mounts is synchronous, ala MNT_WAIT; I don't know.
Sponsored-by: Axcient
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes: #12091
We limit the size of nvlists passed to the kernel so a user cannot make
the kernel do an unreasonably large allocation. On FreeBSD this limit
was 128 kiB, which turns out to be a bit too small when doing some
operations involving a large number of datasets or snapshots, for
example replication.
Make this limit tunable, with a platform-specific auto default.
Linux keeps its limit at KMALLOC_MAX_SIZE. FreeBSD uses 1/4 of the
system limit on user wired memory, which allows it to scale depending
on system configuration.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Issue #6572Closes#10706
In Illumos it is possible to call ioctl functions from within the
kernel by passing the FKIOCTL flag. Neither FreeBSD nor Linux support
that, but it doesn't hurt to keep it around, as all the code is there.
Before this commit it was a dead code and zc_iflags was always zero.
Restore this functionality by allowing to pass a flag to the
zfsdev_ioctl_common() function.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pawel Jakub Dawidek <pawel@dawidek.net>
Closes#10417
The zfsvfs->z_sb field is Linux specified and should be abstracted.
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9697
FreeBSD needs to cope with multiple version of the zfs_cmd_t
structure. Allowing the platform code to pre and post
process the cmd structure makes it possible to work with
legacy tooling.
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9624
Refactor the zfs ioctls in to platform dependent and independent bits.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Signed-off-by: Matthew Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#9301
Mariusz Zaborski
Alan Somers
Ryan Moeller
Pawel Jakub Dawidek
Matthew Macy
Matthew Macy