> -----Original Message----- > From: NeilBrown [mailto:neilb@xxxxxxx] > Sent: Monday, January 30, 2012 1:24 AM > To: Kwolek, Adam > Cc: linux-raid@xxxxxxxxxxxxxxx; Ciechanowski, Ed; Labun, Marcin; Williams, Dan > J > Subject: Re: [PATCH 1/4] FIX: Takeover mdmon when grow is continued from > command line > > On Thu, 12 Jan 2012 08:12:31 +0100 Adam Kwolek <adam.kwolek@xxxxxxxxx> > wrote: > > > When reshape with '--continue' option is executed mdadm doesn't know, > > if mdmon is switched to using '--takeover' option to current file > > system context. To resolve this, on reshape continuation when mdmon is > > run, execute mdmon takeover. > > > > Lack of takeovered mdmon can cause e.g.: > > - multivolume reshape is broken when reshaped volume is changed > > - size of reshaped volume dowsn't increase > > I don't think this is right. > > In particular, the way we seem to be going with systemd means that we might > not end up using '--takeover' at all. So performing a --takeover transparently > without being explicitly asked to is not a good idea. > > --continue is only used once the final root is mounted and all the early boot > complications are out of the way. > So can't we simple require that --takeover - if it is being used - be performed > before any --continue?? > > i.e. is there a reason we cannot ensure this works properly simply by making sure > boot scripts do the right things in the right order. > > NeilBrown This particular patch was written for process automation only. What about remaining patches from this series? BR Adam > > > > > > Signed-off-by: Adam Kwolek <adam.kwolek@xxxxxxxxx> > > --- > > > > Grow.c | 2 ++ > > mdadm.h | 1 + > > util.c | 53 ++++++++++++++++++++++++++++++++++++++++++++--------- > > 3 files changed, 47 insertions(+), 9 deletions(-) > > > > diff --git a/Grow.c b/Grow.c > > index b2c1360..f0422d2 100644 > > --- a/Grow.c > > +++ b/Grow.c > > @@ -3876,6 +3876,8 @@ int Grow_continue_command(char *devname, int > fd, > > */ > > if (!mdmon_running(container_dev)) > > start_mdmon(container_dev); > > + else > > + takeover_mdmon(container_dev); > > ping_monitor(buf); > > > > if (mdmon_running(container_dev)) > > diff --git a/mdadm.h b/mdadm.h > > index 381ef86..f274ae7 100644 > > --- a/mdadm.h > > +++ b/mdadm.h > > @@ -1223,6 +1223,7 @@ extern int mdmon_pid(int devnum); extern int > > check_env(char *name); extern __u32 random32(void); extern int > > start_mdmon(int devnum); > > +extern int takeover_mdmon(int devnum); > > > > extern int child_monitor(int afd, struct mdinfo *sra, struct reshape *reshape, > > struct supertype *st, unsigned long stripes, diff --git > a/util.c > > b/util.c index 6985a70..e95a366 100644 > > --- a/util.c > > +++ b/util.c > > @@ -1581,11 +1581,13 @@ int mdmon_running(int devnum) > > return 0; > > } > > > > -int start_mdmon(int devnum) > > +#define MDMON_TAKEOVER_WAIT_COUNTER 15 int execute_mdmon(int > devnum, > > +int takeover) > > { > > int i, skipped; > > int len; > > - pid_t pid; > > + pid_t pid; > > + pid_t pid_org; > > int status; > > char pathbuf[1024]; > > char *paths[4] = { > > @@ -1611,6 +1613,12 @@ int start_mdmon(int devnum) > > } else > > pathbuf[0] = '\0'; > > > > + if (takeover) { > > + pid_org = mdmon_pid(devnum); > > + if (pid_org < 0) > > + takeover = 0; > > + } > > + > > switch(fork()) { > > case 0: > > /* FIXME yuk. CLOSE_EXEC?? */ > > @@ -1620,24 +1628,51 @@ int start_mdmon(int devnum) > > skipped++; > > else > > skipped = 0; > > - > > - for (i=0; paths[i]; i++) > > - if (paths[i][0]) > > - execl(paths[i], "mdmon", > > - devnum2devname(devnum), > > - NULL); > > + for (i = 0; paths[i]; i++) { > > + if (paths[i][0]) { > > + if (!takeover) > > + execl(paths[i], "mdmon", > > + devnum2devname(devnum), > > + NULL); > > + else > > + execl(paths[i], "mdmon", > > + "--takeover", > > + devnum2devname(devnum), > > + NULL); > > + } > > + } > > exit(1); > > case -1: fprintf(stderr, Name ": cannot run mdmon. " > > "Array remains readonly\n"); > > return -1; > > default: /* parent - good */ > > - pid = wait(&status); > > + i = 0; > > + do { > > + if (i) > > + sleep(1); > > + pid = wait(&status); > > + if (takeover && (pid == pid_org)) > > + pid = -1; > > + i++; > > + } while (takeover && > > + (i < MDMON_TAKEOVER_WAIT_COUNTER) && > > + (pid < 0)); > > if (pid < 0 || status != 0) > > return -1; > > } > > return 0; > > } > > > > +int start_mdmon(int devnum) > > +{ > > + return execute_mdmon(devnum, 0); > > +} > > + > > +int takeover_mdmon(int devnum) > > +{ > > + return execute_mdmon(devnum, 1); > > +} > > + > > int check_env(char *name) > > { > > char *val = getenv(name); -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
