[PATCH 000 of 3] md: Introduction

[PATCH 000 of 3] md: Introduction

[NeilBrown]

Three patches for 2.6.lastest. All should go in 2.6.16.
One won't apply against -rc1-git5 as it fixes a bug in a patch
in -mm that hasn't quite got to -linus yes.

They are mostly little fixes.  I've been doing some more testing,
particularly creating a raid1 over 2 6TB arrays.  This requires
version-1 superblocks, so they have had a bit more testing too.

(No, I didn't try to resync the 6TB raid1.  I created it 
--assume-clean and gave it a write-intent bitmap so a full resync
would never be needed.  If one side died, a recovery would take
ages!!!! but for me it was only an experiment, not a serious configuration).
(You will need mdadm-2.3 if you too want a 6TB raid1).


 [PATCH 001 of 3] md: Handle overflow of mdu_array_info_t->size better.
 [PATCH 002 of 3] md: Assorted little md fixes:
 [PATCH 003 of 3] md: Make sure rdev->size gets set for version-1 superblocks.

[PATCH 001 of 3] md: Handle overflow of mdu_array_info_t->size better.

[NeilBrown]

mdu_array_info_t->size is 'int', which isn't big enough for the
size (in KB of each component in) some arrays.

So rather than a random overflow, set size to -1 when it cannot be set
correctly.

To update aspect on an array, userspace will sometimes:
  get_array_info
  change one field
  set_array_info

in this case, we don't want the '-1' in 'size' to change to size, or
look like a size change at all.  So test for that in update_array_info.



Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~	2006-02-02 16:42:56.000000000 +1100
+++ ./drivers/md/md.c	2006-02-02 16:48:47.000000000 +1100
@@ -2943,6 +2943,8 @@ static int get_array_info(mddev_t * mdde
 	info.ctime         = mddev->ctime;
 	info.level         = mddev->level;
 	info.size          = mddev->size;
+	if (info.size != mddev->size) /* overflow */
+		info.size = -1;
 	info.nr_disks      = nr;
 	info.raid_disks    = mddev->raid_disks;
 	info.md_minor      = mddev->md_minor;
@@ -3524,7 +3526,7 @@ static int update_array_info(mddev_t *md
 		)
 		return -EINVAL;
 	/* Check there is only one change */
-	if (mddev->size != info->size) cnt++;
+	if (info->size >= 0 && mddev->size != info->size) cnt++;
 	if (mddev->raid_disks != info->raid_disks) cnt++;
 	if (mddev->layout != info->layout) cnt++;
 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) cnt++;
@@ -3541,7 +3543,7 @@ static int update_array_info(mddev_t *md
 		else
 			return mddev->pers->reconfig(mddev, info->layout, -1);
 	}
-	if (mddev->size != info->size)
+	if (info->size >= 0 && mddev->size != info->size)
 		rv = update_size(mddev, info->size);
 
 	if (mddev->raid_disks    != info->raid_disks)

[PATCH 002 of 3] md: Assorted little md fixes:

[NeilBrown]

- version-1 superblock
  + The default_bitmap_offset is in sectors, not bytes.
  + the 'size' field in the superblock is in sectors, not KB
- raid0_run should return a negative number on error, not '1'
- raid10_read_balance should not return a valid 'disk' number if
     ->rdev turned out to be NULL
- kmem_cache_destroy doesn't like being passed a NULL.


Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c        |    4 ++--
 ./drivers/md/raid0.c     |    2 +-
 ./drivers/md/raid10.c    |    2 ++
 ./drivers/md/raid5.c     |    3 ++-
 ./drivers/md/raid6main.c |    3 ++-
 5 files changed, 9 insertions(+), 5 deletions(-)

diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~	2006-02-02 16:48:47.000000000 +1100
+++ ./drivers/md/md.c	2006-02-02 16:51:46.000000000 +1100
@@ -1082,7 +1082,7 @@ static int super_1_validate(mddev_t *mdd
 		mddev->size = le64_to_cpu(sb->size)/2;
 		mddev->events = le64_to_cpu(sb->events);
 		mddev->bitmap_offset = 0;
-		mddev->default_bitmap_offset = 1024;
+		mddev->default_bitmap_offset = 1024 >> 9;
 		
 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
 		memcpy(mddev->uuid, sb->set_uuid, 16);
@@ -1163,7 +1163,7 @@ static void super_1_sync(mddev_t *mddev,
 	sb->cnt_corrected_read = atomic_read(&rdev->corrected_errors);
 
 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
-	sb->size = cpu_to_le64(mddev->size);
+	sb->size = cpu_to_le64(mddev->size<<1);
 
 	if (mddev->bitmap && mddev->bitmap_file == NULL) {
 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);

diff ./drivers/md/raid0.c~current~ ./drivers/md/raid0.c
--- ./drivers/md/raid0.c~current~	2006-02-02 16:48:19.000000000 +1100
+++ ./drivers/md/raid0.c	2006-02-02 16:51:53.000000000 +1100
@@ -372,7 +372,7 @@ out_free_conf:
 	kfree(conf);
 	mddev->private = NULL;
 out:
-	return 1;
+	return -ENOMEM;
 }
 
 static int raid0_stop (mddev_t *mddev)

diff ./drivers/md/raid10.c~current~ ./drivers/md/raid10.c
--- ./drivers/md/raid10.c~current~	2006-02-02 16:48:19.000000000 +1100
+++ ./drivers/md/raid10.c	2006-02-02 16:51:53.000000000 +1100
@@ -565,6 +565,8 @@ rb_out:
 
 	if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL)
 		atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
+	else
+		disk = -1;
 	rcu_read_unlock();
 
 	return disk;

diff ./drivers/md/raid5.c~current~ ./drivers/md/raid5.c
--- ./drivers/md/raid5.c~current~	2006-02-02 16:48:19.000000000 +1100
+++ ./drivers/md/raid5.c	2006-02-02 16:51:53.000000000 +1100
@@ -350,7 +350,8 @@ static void shrink_stripes(raid5_conf_t 
 	while (drop_one_stripe(conf))
 		;
 
-	kmem_cache_destroy(conf->slab_cache);
+	if (conf->slab_cache)
+		kmem_cache_destroy(conf->slab_cache);
 	conf->slab_cache = NULL;
 }
 

diff ./drivers/md/raid6main.c~current~ ./drivers/md/raid6main.c
--- ./drivers/md/raid6main.c~current~	2006-02-02 16:48:19.000000000 +1100
+++ ./drivers/md/raid6main.c	2006-02-02 16:55:25.000000000 +1100
@@ -366,7 +366,8 @@ static void shrink_stripes(raid6_conf_t 
 	while (drop_one_stripe(conf))
 		;
 
-	kmem_cache_destroy(conf->slab_cache);
+	if (conf->slab_cache)
+		kmem_cache_destroy(conf->slab_cache);
 	conf->slab_cache = NULL;
 }
 

[PATCH 003 of 3] md: Make sure rdev->size gets set for version-1 superblocks.

[NeilBrown]

Sometimes it doesn't so make the code more like the version-0 code
which works.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~	2006-02-02 16:51:46.000000000 +1100
+++ ./drivers/md/md.c	2006-02-02 16:56:12.000000000 +1100
@@ -1025,7 +1025,7 @@ static int super_1_load(mdk_rdev_t *rdev
 		rdev-> sb_size = (rdev->sb_size | bmask)+1;
 
 	if (refdev == 0)
-		return 1;
+		ret = 1;
 	else {
 		__u64 ev1, ev2;
 		struct mdp_superblock_1 *refsb = 
@@ -1045,7 +1045,9 @@ static int super_1_load(mdk_rdev_t *rdev
 		ev2 = le64_to_cpu(refsb->events);
 
 		if (ev1 > ev2)
-			return 1;
+			ret = 1;
+		else
+			ret = 0;
 	}
 	if (minor_version) 
 		rdev->size = ((rdev->bdev->bd_inode->i_size>>9) - le64_to_cpu(sb->data_offset)) / 2;
@@ -1059,7 +1061,7 @@ static int super_1_load(mdk_rdev_t *rdev
 
 	if (le32_to_cpu(sb->size) > rdev->size*2)
 		return -EINVAL;
-	return 0;
+	return ret;
 }
 
 static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)

Re: [PATCH 000 of 3] md: Introduction

[Mr. James W. Laferriere]

 	Hello Neil ,

On Thu, 2 Feb 2006, NeilBrown wrote:
> Three patches for 2.6.lastest. All should go in 2.6.16.
> One won't apply against -rc1-git5 as it fixes a bug in a patch
> in -mm that hasn't quite got to -linus yes.
>
> They are mostly little fixes.  I've been doing some more testing,
> particularly creating a raid1 over 2 6TB arrays.  This requires
> version-1 superblocks, so they have had a bit more testing too.
>
> (No, I didn't try to resync the 6TB raid1.  I created it
> --assume-clean and gave it a write-intent bitmap so a full resync
> would never be needed.  If one side died, a recovery would take
> ages!!!! but for me it was only an experiment, not a serious configuration).
> (You will need mdadm-2.3 if you too want a 6TB raid1).
>
> [PATCH 001 of 3] md: Handle overflow of mdu_array_info_t->size better.
> [PATCH 002 of 3] md: Assorted little md fixes:
> [PATCH 003 of 3] md: Make sure rdev->size gets set for version-1 superblocks.
 	Would you be so kind and share the commands you ran in order to
 	build this array ?  Please ,  Please !-)   Tia ,  JimL
-- 
+------------------------------------------------------------------+
| James   W.   Laferriere | System    Techniques | Give me VMS     |
| Network        Engineer | 3542 Broken Yoke Dr. |  Give me Linux  |
| babydr@baby-dragons.com | Billings , MT. 59105 |   only  on  AXP |
|  http://www.asteriskhelpdesk.com/cgi-bin/astlance/r.cgi?babydr   |
+------------------------------------------------------------------+

Re: [PATCH 000 of 3] md: Introduction

[Neil Brown]

On Thursday February 2, babydr@baby-dragons.com wrote:
>  	Hello Neil ,
> 
> On Thu, 2 Feb 2006, NeilBrown wrote:
> > Three patches for 2.6.lastest. All should go in 2.6.16.
> > One won't apply against -rc1-git5 as it fixes a bug in a patch
> > in -mm that hasn't quite got to -linus yes.
> >
> > They are mostly little fixes.  I've been doing some more testing,
> > particularly creating a raid1 over 2 6TB arrays.  This requires
> > version-1 superblocks, so they have had a bit more testing too.
> >
> > (No, I didn't try to resync the 6TB raid1.  I created it
> > --assume-clean and gave it a write-intent bitmap so a full resync
> > would never be needed.  If one side died, a recovery would take
> > ages!!!! but for me it was only an experiment, not a serious configuration).
> > (You will need mdadm-2.3 if you too want a 6TB raid1).
> >
> > [PATCH 001 of 3] md: Handle overflow of mdu_array_info_t->size better.
> > [PATCH 002 of 3] md: Assorted little md fixes:
> > [PATCH 003 of 3] md: Make sure rdev->size gets set for version-1 superblocks.
>  	Would you be so kind and share the commands you ran in order to
>  	build this array ?  Please ,  Please !-)   Tia ,  JimL

Well, I don't have 12TB of storage so:

# create some sparse 2G loopback devices
for i in 1 2 3 4 5 6
do
 dd if=/dev/full of=Big$i bs=1024k seek=2000000 count=1
 losetup /dev/loop$i Big$1
done

# combine them into 6G linear arrays
mdadm -C /dev/md4 -l linear -n 3 /dev/loop[123]
mdadm -C /dev/md5 -l linear -n 3 /dev/loop[456]

# now make the 6G mirrored pair.
mdadm -C /dev/md3 -l 1 -n2 --assume-clean --bitmap=internal /dev/md[45]

Providing you are using mdadm 2.3, this will automatically select
version-1 superblocks and create the array marking it clean without
any resync.

Ofcourse, as this particular array is based on sparse files, actually
trying to store much data on it will quickly run you into trouble, but
as a proof-of-implementation, it works OK.

Was that what you were after?

NeilBrown

Re: [PATCH 000 of 3] md: Introduction

[Mr. James W. Laferriere]

  	Hello Neil ,

On Fri, 3 Feb 2006, Neil Brown wrote:
> On Thursday February 2, babydr@baby-dragons.com wrote:
>> On Thu, 2 Feb 2006, NeilBrown wrote:
>>> Three patches for 2.6.lastest. All should go in 2.6.16.
>>> One won't apply against -rc1-git5 as it fixes a bug in a patch
>>> in -mm that hasn't quite got to -linus yes.
>>>
>>> They are mostly little fixes.  I've been doing some more testing,
>>> particularly creating a raid1 over 2 6TB arrays.  This requires
>>> version-1 superblocks, so they have had a bit more testing too.
>>>
>>> (No, I didn't try to resync the 6TB raid1.  I created it
>>> --assume-clean and gave it a write-intent bitmap so a full resync
>>> would never be needed.  If one side died, a recovery would take
>>> ages!!!! but for me it was only an experiment, not a serious configuration).
>>> (You will need mdadm-2.3 if you too want a 6TB raid1).
>>>
>>> [PATCH 001 of 3] md: Handle overflow of mdu_array_info_t->size better.
>>> [PATCH 002 of 3] md: Assorted little md fixes:
>>> [PATCH 003 of 3] md: Make sure rdev->size gets set for version-1 superblocks.
>>  	Would you be so kind and share the commands you ran in order to
>>  	build this array ?  Please ,  Please !-)   Tia ,  JimL

> Well, I don't have 12TB of storage so:
>
> # create some sparse 2G loopback devices
> for i in 1 2 3 4 5 6
> do
> dd if=/dev/full of=Big$i bs=1024k seek=2000000 count=1
> losetup /dev/loop$i Big$1
> done
>
> # combine them into 6G linear arrays
> mdadm -C /dev/md4 -l linear -n 3 /dev/loop[123]
> mdadm -C /dev/md5 -l linear -n 3 /dev/loop[456]
>
> # now make the 6G mirrored pair.
> mdadm -C /dev/md3 -l 1 -n2 --assume-clean --bitmap=internal /dev/md[45]
>
> Providing you are using mdadm 2.3, this will automatically select
> version-1 superblocks and create the array marking it clean without
> any resync.
>
> Ofcourse, as this particular array is based on sparse files, actually
> trying to store much data on it will quickly run you into trouble, but
> as a proof-of-implementation, it works OK.
>
> Was that what you were after?
 	Yes ,  Exactly what I was looking for .  The loop* stuff is not
 	needed for me but the last to commands sure were .
 		Tnx agn ,  JimL
-- 
+------------------------------------------------------------------+
| James   W.   Laferriere | System    Techniques | Give me VMS     |
| Network        Engineer | 3542 Broken Yoke Dr. |  Give me Linux  |
| babydr@baby-dragons.com | Billings , MT. 59105 |   only  on  AXP |
|  http://www.asteriskhelpdesk.com/cgi-bin/astlance/r.cgi?babydr   |
+------------------------------------------------------------------+