From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Helsley Subject: Re: [BUG][cryo] Create file on restart ? Date: Wed, 16 Jul 2008 13:59:23 -0700 Message-ID: <1216241963.4844.133.camel@localhost.localdomain> References: <20080716185027.GA1335@us.ibm.com> <20080716192604.GA27454@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080716192604.GA27454-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: "Serge E. Hallyn" Cc: Containers List-Id: containers.vger.kernel.org On Wed, 2008-07-16 at 14:26 -0500, Serge E. Hallyn wrote: > Quoting sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org (sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org): > > > > cryo does not (cannot ?) recreate files if the application created > > I think that's for the best. > > Don't you? I agree. I think drawing the line for process checkpoint/restart before preserving the contents of mounted filesystems is very reasonable since mounted filesystem(s) can already be preserved with your choice of tool(s). I think it also gives us more options as far as using checkpointed images for error recovery; if we take the concept of checkpoint too far we may limit ourselves to merely reproducing errors rather than also giving ourselves a means to recover from errors. Cheers, -Matt Helsley > -serge > > > a file before checkpoint and the file does not exist at the time > > of restart. > > > > Note that the 'flags' field in '/proc/$pid/fdinfo/$fd' will not > > have the O_CREAT (or O_TRUNC, O_EXCL, O_NOCTTY) flags. These > > are cleared in __dentry_open()). > > > > At the time of restart, is there a way for cryo to know that the > > file must be created ? > > > > To reproduce: > > - run following program, > > - checkpoint after the first printf > > - rm /tmp/foo1 > > - restart # fails to open file during restart > > > > --- > > #include > > #include > > #include > > #include > > > > main() > > { > > int fd; > > int i; > > char *buf = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; > > > > fd = open("/tmp/foo1", O_RDWR|O_CREAT|O_TRUNC, 0666); > > > > if (fd < 0) { > > perror("open"); > > exit(1); > > } > > printf("%d: Opened '/tmp/foo1', fd %d\n", getpid(), fd); > > > > for (i = 0; i < strlen(buf); i++) { > > if (write(fd, &buf[i], 1) < 0) { > > printf("Error %d writing %c to file, i %d\n", > > errno, buf[i], i); > > exit(1); > > } > > printf("%d: i %d, wrote %c\n", getpid(), i, buf[i]); > > sleep(2); > > } > > } > > _______________________________________________ > > Containers mailing list > > Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org > > https://lists.linux-foundation.org/mailman/listinfo/containers > _______________________________________________ > Containers mailing list > Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org > https://lists.linux-foundation.org/mailman/listinfo/containers