ZED uses an advisory lock on its state file to protect against
multiple instances running concurrently. However, work is planned
to move this state information into the kernel, and ZED will still
need to protect against starting multiple instances.
This commit adds an advisory lock on the PID file to protect against
starting multiple instances. A lock failure can be overridden with
the "-f" (force) command-line option. The advisory lock on the state
file is being retained for as long as the state information is stored
in the state file.
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2756
Remove all occurrences of reverse indentation from zed comments for
consistency within the project code base.
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2695
When the zed is started as a forking daemon (by default),
a race-condition exists where the parent process can terminate before
the pidfile has been created by the grandchild process. When invoked
as a Type=forking systemd service, this can result in the following:
systemd[1]: Starting ZFS Event Daemon (zed)...
systemd[1]: PID file /var/run/zed.pid not readable (yet?) after start.
This commit adds a daemonize pipe to allow the grandchild process to
signal the parent process that initialization is complete (and the
pidfile has been created). The parent process will wait for this
notification before exiting.
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2252
zed supports a '-M' cmdline opt to lock all pages in memory via
mlockall(). The _POSIX_MEMLOCK define is checked to determine whether
this function is supported. The current test assumes mlockall()
is supported if _POSIX_MEMLOCK is non-zero. However, this test is
insufficient according to mlock(2) and sysconf(3). If _POSIX_MEMLOCK
is -1, mlockall() is not supported; but if _POSIX_MEMLOCK is 0,
availability must be checked at runtime.
This commit adds an autoconf check for mlockall() to user.m4. The zed
code block for mlockall() is now guarded with a test for HAVE_MLOCKALL.
If defined, mlockall() will be called and its runtime availability
checked via its return value.
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2
zed monitors ZFS events. When a zevent is posted, zed will run any
scripts that have been enabled for the corresponding zevent class.
Multiple scripts may be invoked for a given zevent. The zevent
nvpairs are passed to the scripts as environment variables.
Events are processed synchronously by the single thread, and there is
no maximum timeout for script execution. Consequently, a misbehaving
script can delay (or forever block) the processing of subsequent
zevents. Plans are to address this in future commits.
Initial scripts have been developed to log events to syslog
and send email in response to checksum/data/io errors and
resilver.finish/scrub.finish events. By default, email will only
be sent if the ZED_EMAIL variable is configured in zed.rc (which is
serving as a config file of sorts until a proper configuration file
is implemented).
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2
Chris Dunlap