mirror_zfs/cmd
John Gallagher e60e158eff Add subcommand to wait for background zfs activity to complete
Currently the best way to wait for the completion of a long-running
operation in a pool, like a scrub or device removal, is to poll 'zpool
status' and parse its output, which is neither efficient nor convenient.

This change adds a 'wait' subcommand to the zpool command. When invoked,
'zpool wait' will block until a specified type of background activity
completes. Currently, this subcommand can wait for any of the following:

 - Scrubs or resilvers to complete
 - Devices to initialized
 - Devices to be replaced
 - Devices to be removed
 - Checkpoints to be discarded
 - Background freeing to complete

For example, a scrub that is in progress could be waited for by running

    zpool wait -t scrub <pool>

This also adds a -w flag to the attach, checkpoint, initialize, replace,
remove, and scrub subcommands. When used, this flag makes the operations
kicked off by these subcommands synchronous instead of asynchronous.

This functionality is implemented using a new ioctl. The type of
activity to wait for is provided as input to the ioctl, and the ioctl
blocks until all activity of that type has completed. An ioctl was used
over other methods of kernel-userspace communiction primarily for the
sake of portability.

Porting Notes:
This is ported from Delphix OS change DLPX-44432. The following changes
were made while porting:

 - Added ZoL-style ioctl input declaration.
 - Reorganized error handling in zpool_initialize in libzfs to integrate
   better with changes made for TRIM support.
 - Fixed check for whether a checkpoint discard is in progress.
   Previously it also waited if the pool had a checkpoint, instead of
   just if a checkpoint was being discarded.
 - Exposed zfs_initialize_chunk_size as a ZoL-style tunable.
 - Updated more existing tests to make use of new 'zpool wait'
   functionality, tests that don't exist in Delphix OS.
 - Used existing ZoL tunable zfs_scan_suspend_progress, together with
   zinject, in place of a new tunable zfs_scan_max_blks_per_txg.
 - Added support for a non-integral interval argument to zpool wait.

Future work:
ZoL has support for trimming devices, which Delphix OS does not. In the
future, 'zpool wait' could be extended to add the ability to wait for
trim operations to complete.

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Gallagher <john.gallagher@delphix.com>
Closes #9162
2019-09-13 18:09:06 -07:00
..
arc_summary Canonicalize Python shebangs 2019-09-12 13:32:32 -07:00
arcstat Canonicalize Python shebangs 2019-09-12 13:32:32 -07:00
dbufstat Canonicalize Python shebangs 2019-09-12 13:32:32 -07:00
fsck_zfs Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
mount_zfs Add libzutil for libzfs or libzpool consumers 2018-11-05 11:22:33 -08:00
raidz_test Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
vdev_id Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
zdb Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
zed Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
zfs Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
zgenhostid Add zgenhostid utility script 2017-07-25 13:22:03 -04:00
zhack Add libzutil for libzfs or libzpool consumers 2018-11-05 11:22:33 -08:00
zinject Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
zpool Add subcommand to wait for background zfs activity to complete 2019-09-13 18:09:06 -07:00
zstreamdump Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
ztest Fix typos in cmd/ 2019-08-30 09:43:30 -07:00
zvol_id Fedora 28: Fix misc bounds check compiler warnings 2018-04-04 10:16:47 -07:00
zvol_wait zvol_wait script should ignore partially received zvols 2019-09-03 11:29:52 -07:00
Makefile.am New service that waits on zvol links to be created 2019-07-17 15:33:05 -07:00