Eucalyptus

[patch] improve locking mechanizm during staging process

Bug #520555 reported by Stanislav Ievlev on 2010-02-11

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	Eucalyptus	In Progress	Medium	Dmitrii Zagorodnov	Eucalyptus 2.0.4

Bug Description

Current locking implementation during staging process will not properly work on network filesystems (we are using a shared cache for all machines in cluster).
I've replaced a simple touch() and unlink() calls with a more perfect solution.

My functions use both fcntl and mutexes. This technique prevents a race conditions both between a local threads in one process
and between different processes on different machines.

Revision history for this message

Stanislav Ievlev (stanislav-ievlev) wrote on 2010-02-11:

solution of the problem Edit (5.6 KiB, text/x-diff)

Dmitrii Zagorodnov (dmitrii) on 2010-10-18

Changed in eucalyptus:
assignee:	nobody → Dmitrii Zagorodnov (dmitrii)

Revision history for this message

Dmitrii Zagorodnov (dmitrii) wrote on 2011-03-01:

Hi Stanislav,

Thanks a lot for the patch, I'm adding it to the 2.0.* code branch. I'll remove the

sem_v (disk_sem);
...
sem_p (disk_sem);

pair, because lock_file_aquire() is already called with sc_sem held and disk_sem is used to serialize long-running disk operations in storage.c. Does that make sense?

Regards,
Dmitrii

graziano obertelli (graziano.obertelli) on 2011-12-04