[Bacula-announce] Another critical bug

[Kern S. <ke...@si...>]

Hello,

Since the last critical bug we had the 14th of September, I have been spending 
most of my time debugging, creating new tests, and running them.  I've now 
resolved a good number of bug, all of which have been around for quite some 
time (at least since version 2.0.0, and some much older).

We have ported the most important ones back to version 2.2.4 in the form of 
patches which are attached to the bug reports and in the Source Forge 
bacula-patches 2.2.x release area.

During this debugging and testing (still continuing), I found and fixed a 
serious data lost bug in Bacula, which it the primary reason for this 
notification.

This bug was very elusive and time consuming to track down. It turned out to 
be a race condition that can lose the last one or two blocks of a Job, which 
can happen in rare cases only when running multiple simultaneous jobs when a 
volume fills and one Job finishes receiving the last data from the FD and at 
the same time a second job detects the end of the Volume.  The bug was 
introduced in version 2.0.0 and did not exist in version 1.38.x. If the bug 
is triggered, the data is lost (not written to the Volume), and it can occur 
for any backup job of any level under the conditions noted above.

The bug is reported in the bugs database as bug #964, and just this morning I 
found and tested a fix, which is attached as a patch to the bug report.  The 
patch (2.2.4-lost-block.patch) is also uploaded to the bacula-patches 2.2.x 
release area.  The problems reported in bug #935 and #903 could possibly be 
due in part because of this bug.

Also in the bacula-patches 2.2.x area, you will find other patches that fix 
bugs #953, 966, 967, 965, 958, 908, and 955. Please refer to bugs.bacula.org 
for the details.

I have also posted a news item regarding this bug on the bacula web site.

We still considering if any other bug fixes that are in the current SVN should 
be back ported to version 2.2.4 so that we can make a 2.2.5 bug fix release 
later next week.  This bug fixing will probably continue for some time since 
recently we have had a flurry of bug reports, with a few exceptions most all 
are long standing bugs.

Though this bug quite serious (data loss), it should be rare.  However, we 
recommend everyone to apply the patch.

I regret any inconvenience this causes.

Best regards,

Kern