From: Neil Brown <neilb@suse.de>
To: Frank Corrao <fcorrao@temp555.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: reshaping raid6 in-place
Date: Thu, 13 May 2010 13:18:53 +1000 [thread overview]
Message-ID: <20100513131853.2730a688@notabene.brown> (raw)
In-Reply-To: <alpine.LRH.2.00.1005122233430.25542@appaloosa.temp555.com>
On Wed, 12 May 2010 22:41:52 -0400 (EDT)
Frank Corrao <fcorrao@temp555.com> wrote:
> On Thu, 13 May 2010, Neil Brown wrote:
>
> > On Wed, 12 May 2010 19:10:35 -0400 (EDT)
> > Frank Corrao <fcorrao@temp555.com> wrote:
> >
> >> I have a 5-disk raid5 array which I recently reshaped to raid6 while
> >> simultaneously adding a 6th disk. mdadm (3.1.1) reported that the
> >> kernel I was running at the time (2.6.30) wasn't safe to perform the
> >> in-place portion of the reshaping. The array was partitionally
> >> converted to raid6, but I believe the Q blocks are all on the last
> >> device I added. mdadm seems to report the algorithm as
> >> left-symmetric-6 as opposed to left-symmetric. Today I upgraded to
> >> 2.6.32 and mdadm 3.1.2 and attempted to complete the re-shaping but ran
> >> into a snag:
> >>
> >> $ sudo ./mdadm -v --grow /dev/md2 -l 6 -n 6 -p left-symmetric
> >> mdadm: /dev/md2: Something wrong - reshape aborted
> >>
> >> Is my syntax correct?
> >>
> >> Frank
> >
> > This is a 32bit host isn't it??? You would have thought I would have learned
> > by now, but it seems not. 'blocks' in Grow.c is "unsigned long" and should
> > really be "unsigned long long".
>
> Actually no - its x86_64. I applied the patch, corrected the fprintf()
> call on line 961 and recompiled but I still get the same error.
>
Strange....
The error comes from
if (blocks >= sra->component_size/2) {
fprintf(stderr, Name ": %s: Something wrong - reshape aborted\n",
devname);
rv = 1;
break;
}
as odata == ndate (==4), blocks should be 32768.
sra->component_size should be 2860853248 (it is in sectors, so double the
number of kilobytes).
So that wouldn't overflow even on 32bit... so my original analysis was
obviously wrong, as you discovered.
Could you print some printfs in there to find out what the values of
blocks, sra->component_size, a, b, ochunk, nchuck, odata, ndata
are?
Also, while it isn't wrong to give "-l 6 -n 6" it is redundant because the
array is already that size/shape.
I would just use:
mdadm -v --grow /dev/md0 --layout=normalise --backup-file=/root/md2.backup
once we sort out why is wrong with 'blocks'.
NeilBrown
>
> > Also your syntax is incomplete. You need a backup-file for that reshape.
> > mdadm would have told you that if it hadn't confused itself first.
>
> No change when adding the --backup-file option:
>
> $ sudo ./mdadm -v --grow /dev/md2 -l 6 -n 6 -p left-symmetric --backup-file=/root/md2.backup
> mdadm: /dev/md2: Something wrong - reshape aborted
>
>
> Frank
>
>
>
>
> > This patch should help you.
> >
> > NeilBrown
> >
> > diff --git a/Grow.c b/Grow.c
> > index 0916c5d..d1a7b63 100644
> > --- a/Grow.c
> > +++ b/Grow.c
> > @@ -418,15 +418,15 @@ int bsb_csum(char *buf, int len)
> > return __cpu_to_le32(csum);
> > }
> >
> > -static int child_grow(int afd, struct mdinfo *sra, unsigned long blocks,
> > +static int child_grow(int afd, struct mdinfo *sra, unsigned long long blocks,
> > int *fds, unsigned long long *offsets,
> > int disks, int chunk, int level, int layout, int data,
> > int dests, int *destfd, unsigned long long *destoffsets);
> > -static int child_shrink(int afd, struct mdinfo *sra, unsigned long blocks,
> > +static int child_shrink(int afd, struct mdinfo *sra, unsigned long long blocks,
> > int *fds, unsigned long long *offsets,
> > int disks, int chunk, int level, int layout, int data,
> > int dests, int *destfd, unsigned long long *destoffsets);
> > -static int child_same_size(int afd, struct mdinfo *sra, unsigned long blocks,
> > +static int child_same_size(int afd, struct mdinfo *sra, unsigned long long blocks,
> > int *fds, unsigned long long *offsets,
> > unsigned long long start,
> > int disks, int chunk, int level, int layout, int data,
> > @@ -514,7 +514,7 @@ int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
> > int nrdisks;
> > int err;
> > int frozen;
> > - unsigned long a,b, blocks, stripes;
> > + unsigned long long a,b, blocks, stripes;
> > int cache;
> > unsigned long long array_size;
> > int changed = 0;
> > @@ -1262,7 +1262,7 @@ int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
> > /* FIXME return status is never checked */
> > int grow_backup(struct mdinfo *sra,
> > unsigned long long offset, /* per device */
> > - unsigned long stripes, /* per device */
> > + unsigned long long stripes, /* per device */
> > int *sources, unsigned long long *offsets,
> > int disks, int chunk, int level, int layout,
> > int dests, int *destfd, unsigned long long *destoffsets,
> > @@ -1522,7 +1522,7 @@ static void validate(int afd, int bfd, unsigned long long offset)
> > }
> > }
> >
> > -static int child_grow(int afd, struct mdinfo *sra, unsigned long stripes,
> > +static int child_grow(int afd, struct mdinfo *sra, unsigned long long stripes,
> > int *fds, unsigned long long *offsets,
> > int disks, int chunk, int level, int layout, int data,
> > int dests, int *destfd, unsigned long long *destoffsets)
> > @@ -1550,7 +1550,7 @@ static int child_grow(int afd, struct mdinfo *sra, unsigned long stripes,
> > return 1;
> > }
> >
> > -static int child_shrink(int afd, struct mdinfo *sra, unsigned long stripes,
> > +static int child_shrink(int afd, struct mdinfo *sra, unsigned long long stripes,
> > int *fds, unsigned long long *offsets,
> > int disks, int chunk, int level, int layout, int data,
> > int dests, int *destfd, unsigned long long *destoffsets)
> > @@ -1586,14 +1586,14 @@ static int child_shrink(int afd, struct mdinfo *sra, unsigned long stripes,
> > return 1;
> > }
> >
> > -static int child_same_size(int afd, struct mdinfo *sra, unsigned long stripes,
> > +static int child_same_size(int afd, struct mdinfo *sra, unsigned long long stripes,
> > int *fds, unsigned long long *offsets,
> > unsigned long long start,
> > int disks, int chunk, int level, int layout, int data,
> > int dests, int *destfd, unsigned long long *destoffsets)
> > {
> > unsigned long long size;
> > - unsigned long tailstripes = stripes;
> > + unsigned long long tailstripes = stripes;
> > int part;
> > char *buf;
> > unsigned long long speed;
> > @@ -1960,7 +1960,7 @@ int Grow_continue(int mdfd, struct supertype *st, struct mdinfo *info,
> > int backup_list[1];
> > unsigned long long backup_offsets[1];
> > int odisks, ndisks, ochunk, nchunk,odata,ndata;
> > - unsigned long a,b,blocks,stripes;
> > + unsigned long long a,b,blocks,stripes;
> > int backup_fd;
> > int *fds;
> > unsigned long long *offsets;
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2010-05-13 3:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-12 23:10 reshaping raid6 in-place Frank Corrao
2010-05-13 2:08 ` Neil Brown
2010-05-13 2:41 ` Frank Corrao
2010-05-13 3:18 ` Neil Brown [this message]
2010-05-13 4:04 ` Frank Corrao
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