Re: [PATCH v2 5/9] Move buildchroot mounts into dpkg-base class

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2018-02-13 21:17, Alexander Smirnov wrote:
> 
> 
> On 02/13/2018 11:05 PM, Jan Kiszka wrote:
>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>
>> This avoids the unfortunate setup_mounts task which is either not
>> executed on rebuilds or causes excessive package rebuilds. We just need
>> ensure prior to switching into the buildchroot that all mount points are
>> populated.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>   meta/classes/dpkg-base.bbclass                   | 13 +++++++++-
>>   meta/recipes-devtools/buildchroot/buildchroot.bb | 30
>> +++---------------------
>>   2 files changed, 15 insertions(+), 28 deletions(-)
>>
>> diff --git a/meta/classes/dpkg-base.bbclass
>> b/meta/classes/dpkg-base.bbclass
>> index a45fbce..66132da 100644
>> --- a/meta/classes/dpkg-base.bbclass
>> +++ b/meta/classes/dpkg-base.bbclass
>> @@ -2,7 +2,7 @@
>>   # Copyright (C) 2017 Siemens AG
>>     # Add dependency from buildchroot creation
>> -do_build[depends] = "buildchroot:do_setup_mounts"
>> +do_build[depends] = "buildchroot:do_build"
>>     # Add dependency between Isar recipes
>>   DEPENDS ?= ""
>> @@ -20,11 +20,22 @@ dpkg_runbuild() {
>>       die "This should never be called, overwrite it in your derived
>> class"
>>   }
>>   +mount_if_needed() {
>> +
>> +    # The test may race with parallel builds. So probe, mount if
>> needed, and
>> +    # then only fail if both the mount and yet another probe failed
>> as well.
>> +    grep -q $2 /proc/mounts || sudo mount $1 $2 || grep -q $2
>> /proc/mounts
> 
> This could lead to have lots of remounts on the same folder during
> parallel execution. This should be done in a separate task and protected
> by [lockfiles].

No, it won't - please re-read the code. It's a classic retry pattern,
and it's even detecting errors.

Jan

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