On Thu, 9 Feb 2012 08:16:16 +0000 "Kwolek, Adam" <adam.kwolek@xxxxxxxxx> wrote: > > > > -----Original Message----- > > From: NeilBrown [mailto:neilb@xxxxxxx] > > Sent: Thursday, February 09, 2012 02:36 > > To: Kwolek, Adam > > Cc: linux-raid@xxxxxxxxxxxxxxx; Ciechanowski, Ed; Labun, Marcin; Williams, Dan > > J; Dorau, Lukasz > > Subject: Re: [PATCH 08/12] FIX: use md position to reshape restart > > > > On Tue, 07 Feb 2012 15:03:59 +0100 Adam Kwolek <adam.kwolek@xxxxxxxxx> > > wrote: > > > > > When reshape is broken, it can occur that metadata is not saved properly. > > > This can cause that reshape process is farther in md than metadata states. > > > > > > On reshape restart use md position as start position, if it is farther > > > than position specified in metadata. Opposite situation treat as error. > > > > > > Signed-off-by: Adam Kwolek <adam.kwolek@xxxxxxxxx> > > > --- > > > > > > Grow.c | 86 +++++++++++++++++++++++++++++++++++++++++++++----------- > > -------- > > > 1 files changed, 60 insertions(+), 26 deletions(-) > > > > > > diff --git a/Grow.c b/Grow.c > > > index 70bdee1..0668a16 100644 > > > --- a/Grow.c > > > +++ b/Grow.c > > > @@ -1862,6 +1862,55 @@ release: > > > return rv; > > > } > > > > > > +/* verify_reshape_position() > > > + * Function checks if reshape position in metadata is not farther > > > + * than position in md. > > > + * Return value: > > > + * 0 : not valid sysfs entry > > > + * it can be caused by not started reshape, it should be started > > > + * by reshape array or raid0 array is before takeover > > > + * -1 : error, reshape position is obviously wrong > > > + * 1 : success, reshape progress correct or updated > > > +*/ > > > +static int verify_reshape_position(struct mdinfo *info, int level) { > > > + int ret_val = 0; > > > + char buf[40]; > > > + > > > + /* read sync_max, failure can mean raid0 array */ > > > + if (sysfs_get_str(info, NULL, "sync_max", buf, 40) > 0) { > > > + char *ep; > > > + unsigned long long position = strtoull(buf, &ep, 0); > > > + > > > + dprintf(Name": Read sync_max sysfs entry is: %s\n", buf); > > > + if (!(ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))) { > > > + position *= get_data_disks(level, > > > + info->new_layout, > > > + info->array.raid_disks); > > > + if (info->reshape_progress < position) { > > > + dprintf("Corrected reshape progress (%llu) to " > > > + "md position (%llu)\n", > > > + info->reshape_progress, position); > > > + info->reshape_progress = position; > > > + ret_val = 1; > > > + } else if (info->reshape_progress > position) { > > > + fprintf(stderr, Name ": Fatal error: array " > > > + "reshape was not properly frozen " > > > + "(expected reshape position is %llu, " > > > + "but reshape progress is %llu.\n", > > > + position, info->reshape_progress); > > > + ret_val = -1; > > > + } else { > > > + dprintf("Reshape position in md and metadata " > > > + "are the same;"); > > > + ret_val = 1; > > > + } > > > + } > > > + } > > > + > > > + return ret_val; > > > +} > > > + > > > static int reshape_array(char *container, int fd, char *devname, > > > struct supertype *st, struct mdinfo *info, > > > int force, struct mddev_dev *devlist, @@ -2251,9 > > +2300,16 @@ > > > started: > > > > > > sra->new_chunk = info->new_chunk; > > > > > > - if (restart) > > > + if (restart) { > > > + /* for external metadata checkpoint saved by mdmon can be > > lost > > > + * or missed /due to e.g. crash/. Check if md is not during > > > + * restart farther than metadata points to. > > > + * If so, this means metadata information is obsolete. > > > + */ > > > + if (st->ss->external) > > > + verify_reshape_position(info, reshape.level); > > > sra->reshape_progress = info->reshape_progress; > > > - else { > > > + } else { > > > sra->reshape_progress = 0; > > > if (reshape.after.data_disks < reshape.before.data_disks) > > > /* start from the end of the new array */ @@ -3765,8 > > +3821,6 @@ > > > int Grow_continue_command(char *devname, int fd, > > > char buf[40]; > > > int cfd = -1; > > > int fd2 = -1; > > > - char *ep; > > > - unsigned long long position; > > > > > > dprintf("Grow continue from command line called for %s\n", > > > devname); > > > @@ -3894,28 +3948,8 @@ int Grow_continue_command(char *devname, int > > fd, > > > /* verify that array under reshape is started from > > > * correct position > > > */ > > > - ret_val = sysfs_get_str(content, NULL, "sync_max", buf, 40); > > > - if (ret_val <= 0) { > > ^^^ > > > > This test is '<=' however ... > > > > > > > - fprintf(stderr, Name > > > - ": cannot open verify reshape progress for %s (%i)\n", > > > - content->sys_name, ret_val); > > > - ret_val = 1; > > > - goto Grow_continue_command_exit; > > > - } > > > - dprintf(Name ": Read sync_max sysfs entry is: %s\n", buf); > > > - position = strtoull(buf, &ep, 0); > > > - if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' ')) { > > > - fprintf(stderr, Name ": Fatal error: array reshape was" > > > - " not properly frozen\n"); > > > - ret_val = 1; > > > - goto Grow_continue_command_exit; > > > - } > > > - position *= get_data_disks(map_name(pers, mdstat->level), > > > - content->new_layout, > > > - content->array.raid_disks); > > > - if (position != content->reshape_progress) { > > > - fprintf(stderr, Name ": Fatal error: array reshape was" > > > - " not properly frozen.\n"); > > > + if (verify_reshape_position(content, > > > + map_name(pers, mdstat->level)) < 0) { > > ^^ > > > > this one is just '<'. However it looks like it should be the same. > > > > Was there a reason for the change, or was it an oversight? > > > > Thanks, > > NeilBrown > > > > > > > > > > > ret_val = 1; > > > goto Grow_continue_command_exit; > > > } > > > Removed code is put in to function verify_reshape_position() for use in current location and reshape_array(), > as calculated new position in Grow_continue_command() cannot be passed to reshape_array(), it has to be calculated again. > > This is what you are mention above? Not exactly. The original code would print an error if sysfs_get_str(content, NULL, "sync_max", buf, 40); returns 0 or negative. The new code will not print an error if that returns zero. i.e. you changed a '<=' into a '<'. I wondered if there was some reason for that - something that I was missing. NeilBrown
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