Replace the perl locking check with stat(1). Stat is able to fstat
stdin (file descriptor 0) when passed '-' as an argument. This is now
used to check $_lockfd. stat(1) support for '-' was introduced to
coreutils in 2009.
After A releases its lock, script B will return from flock and execute
stat. Since the lockfile has been removed by A, stat prints an error to
stderr and exits non-zero. Redirect stderr to /dev/null to avoid
filling /var/log/xen/xen-hotplug.log with "No such file or directory"
messages.
Placing the stat call inside the "if" condition ensures we only check
the stat output when the command completed successfully.
This change removes the only runtime dependency of the xen toolstack on
perl.
Suggested-by: Ian Jackson <ian.jackson@citrix.com>
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Replace two stray tabs with spaces to make the file whitespace
consistent.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Wei Liu <wl@xen.org>
As recommended in http://www.gnu.org/licenses/gpl-howto.en.html.
This is the result of:
$ git grep -El Mass\|Temple\|Franklin | xargs ./fsf.pl
Where fsf.pl is:
#!/usr/bin/perl -w -pi.bak -0777
my $repl = 'If not, see <http://www.gnu.org/licenses/>.';
my $br = qr/(?:\s*\n\s*(?:[\*\#]|\/\/|\.\\" )?\s*|\s+)/;
my $inwt = qr/[Ii]f${br}not,${br}write${br}(?:to${br})?the${br}Free${br}Software${br}Foundation,(?:${br}Inc\.,)?/;
my $mass = qr/675${br}Mass${br}Ave,?${br}Cambridge,?${br}MA${br}02139,?${br}USA,?\.?/;
my $franklin = qr/51${br}Franklin${br}St(?:reet)?(?:,${br}| - )Fifth${br}Floor,?${br}Boston,?${br}MA,?${br}02110-1301,?${br}USA,?\.?/;
my $temple = qr/59${br}Temple${br}Place(?:,${br}| - )Suite${br}330,?${br}Boston,?${br}MA,?${br}021110?-1307,?${br}USA,?\.?/;
s|$inwt$br$mass|$repl|m;
s|$inwt$br$franklin|$repl|m;
s|$inwt$br$temple|$repl|m;
The only remaining mentions of these addresses are in COPYING files which I
haven't touched.
Some of the changed files are imports from elsewhere, however
filtering them out is tricky, I think it is tolerable to have these
files be modified here and then perhaps reverted on the next sync,
since it's only 1-2 lines and obvious what is going on.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
The claim_lock() function would fail in the perl code with:
Invalid argument at -e line 2.
because the Perl snippet opens for reading the file descriptor, which
was earlier opened for write (append).
Signed-off-by: Jacek Konieczny <jajcus@jajcus.net>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
When a HVM guest is shutdown some of the 'remove' events can not claim
the lock for some reason. Instead they try to grab the lock in a busy
loop, until udev reaps the xen-hotplug-cleanup helper.
After analyzing the resulting logfile its not obvious what the cause is.
The only explanation is that bash (?) gets confused if the same lockfd
is opened again and again. Closing it in each iteration seem to fix the
issue.
This was observed with sles11sp2 (bash 3.2) and 4.2 xend.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <Ian.campbell@citrix.com>
[ ijc -- added the comment ]
Committed-by: Ian Campbell <ian.campbell@citrix.com>
25590:bb250383a4f5 introduced a new locking scheme. Unfortunately it
leaves behind files in /var/run/xen-hotplug. These are spotted as
regressions by the autotester.
Fix this. This involves changing the locking protocol to allow
lockfiles to be deleted (as removing lockfiles is unsafe with a naive
flock-based algorithm).
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
In the normal case of a single domain booting with one disk, the disk hotplug
script will fire once. In this case taking out the lock will never cause a
sleep because there's no other concurrent invocations. If a domain has 4 disks
configured, then the hotplug script will fire 4 times, all 4 invocations at
pretty much the same time. If there is even a little load on the system, the
locking function in the shell script will sleep for a few seconds - as many as
5 seconds, or potentially even time out & fail completely.
If say 4 or even more domains each with 4 disks start up at once, that's 16
invocations of the hotplug script running at once. There will be a lot of
sleep's done & because of the very coarse 1 second granularity the delay can
add up significantly.
The change to using flock() removes the arbitrary 1 second sleep, so the very
instant once hotplug script finishes, another can start & there is no repeated
attempts & failures to lock which would add more delay.
In addition the current locking implementation would allow two processes get
the lock simultaneously if one decided the other had timed out.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Zhigang Wang <zhigang.x.wang@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
22508:57907b28e51a was unsafe for mutual exclusion. There is a case
that the owner file doesn't exist yet when an atomic mkdir operation
fails.
Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
When a script using locking.sh is stopped by ctrl-C, the lock file remains.
We have to wait 100 seconds for releasing the lock at the next time.
Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
_release_lock should be used instead of release_lock.
sigerr is introduced so that it can be redefined by
xen-hotplug-common.sh to a version which writes error status to xenstore.
Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>
Jason Andryuk