zfs/lib
Don Brady e625030c11 OpenZFS 9425 - channel programs can be interrupted
Problem Statement
=================
ZFS Channel program scripts currently require a timeout, so that hung or
long-running scripts return a timeout error instead of causing ZFS to get
wedged. This limit can currently be set up to 100 million Lua instructions.
Even with a limit in place, it would be desirable to have a sys admin
(support engineer) be able to cancel a script that is taking a long time.

Proposed Solution
=================
Make it possible to abort a channel program by sending an interrupt signal.In
the underlying txg_wait_sync function, switch the cv_wait to a cv_wait_sig to
catch the signal. Once a signal is encountered, the dsl_sync_task function can
install a Lua hook that will get called before the Lua interpreter executes a
new line of code. The dsl_sync_task can resume with a standard txg_wait_sync
call and wait for the txg to complete.  Meanwhile, the hook will abort the
script and indicate that the channel program was canceled. The kernel returns
a EINTR to indicate that the channel program run was canceled.

Porting notes: Added missing return value from cv_wait_sig()

Authored by: Don Brady <don.brady@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Sara Hartse <sara.hartse@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Robert Mustacchi <rm@joyent.com>
Ported-by: Don Brady <don.brady@delphix.com>
Signed-off-by: Don Brady <don.brady@delphix.com>

OpenZFS-issue: https://www.illumos.org/issues/9425
OpenZFS-commit: https://github.com/illumos/illumos-gate/commit/d0cb1fb926
Closes #8904
2020-01-22 13:48:56 -08:00
..
libavl Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
libefi Remove libefi __linux__ wrappers 2018-06-14 09:43:32 -07:00
libicp Add support for selecting encryption backend 2018-08-02 11:59:24 -07:00
libnvpair config: better libtirpc detection 2019-03-02 16:19:05 -08:00
libshare Fedora 28: Fix misc bounds check compiler warnings 2018-08-26 12:55:44 -07:00
libspl ZFS Reads may result in unneccesary calls to zil_commit 2019-03-22 13:09:11 -07:00
libtpool Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
libunicode Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
libuutil Update build system and packaging 2018-05-29 16:00:33 -07:00
libzfs Always refuse receving non-resume stream when resume state exists 2019-09-25 11:27:51 -07:00
libzfs_core Use ZFS_DEV macro instead of literals 2019-09-25 11:27:48 -07:00
libzpool OpenZFS 9425 - channel programs can be interrupted 2020-01-22 13:48:56 -08:00
libzutil Sort by full path name instead of by GUID when importing 2019-02-26 11:13:15 -08:00
Makefile.am Add libzutil for libzfs or libzpool consumers 2018-11-05 11:22:33 -08:00