On Tue, Nov 19, 2013 at 11:16:58PM +, Duncan wrote:
> Hugo Mills posted on Tue, 19 Nov 2013 09:06:02 + as excerpted:
>
> > This will happen with RAID-10. The allocator will write stripes as wide
> > as it can: in this case, the first stripes will run across all 8
> > devices, until the SSD
Here is another way in which btrfs-tools crashes if it sees things it
doesn't like.
Is anyone interested in those, or not really?
gandalfthegreat:/tmp# btrfs-find-root /dev/mapper/ssdcrypt
Check tree block failed, want=20971520, have=10422900740180685247
Check tree block failed, want=20971520, h
On Nov 19, 2013, at 11:35 PM, Martin wrote:
> On 19/11/13 23:16, Duncan wrote:
>
>> So we have:
>>
>> 1) raid1 is exactly two copies of data, paired devices.
>>
>> 2) raid0 is a stripe exactly two devices wide (reinforced by to read a
>> stripe takes only two devices), so again paired device
On Wed, 20 Nov 2013, Chris Murphy wrote:
> Hot spares are worse than useless. Especially for raid10. The drive takes
> up space doing nothing but suck power, rather than adding space or
> performance. Somehow this idea comes from cheap companies who seem to
> think their data is so valuable they n
Dear list members,
After a quick directory defragging, I tried to start the mysql daemon. Then
suddenly to following appeared in the kernel log and the whole system hung up.
This log is also from an instant copy over SSH.
Now I'm planning to run a btrfsck on the file system, also.
[ 4878.25575
On 19/11/13 18:36, Andrea Mazzoleni wrote:
> Hi David,
>
> Just to say that I know your good past work, and it helped me a lot.
> Thanks for that!
If we end up with your Cauchy matrix implementation going into the
kernel and btrfs (and you've persuaded me, anyway), then perhaps I
should make a ne
On 20/11/13 02:23, John Williams wrote:
> On Tue, Nov 19, 2013 at 4:54 PM, Chris Murphy
> wrote:
>> If anything, I'd like to see two implementations of RAID 6 dual
>> parity. The existing implementation in the md driver and btrfs could
>> remain the default, but users could opt into Cauchy matrix
On 19/11/13 19:12, Piergiorgio Sartor wrote:
> On Mon, Nov 18, 2013 at 11:08:59PM +0100, Andrea Mazzoleni wrote:
>
> Hi Andrea,
>
> great job, this was exactly what I was looking for.
>
> Do you know if there is a "fast" way not to correct
> errors, but to find them?
>
> In RAID-6 (as per ra
On Wed, Nov 20, 2013 at 10:28 AM, Szőts Ákos wrote:
> Dear list members,
>
> After a quick directory defragging, I tried to start the mysql daemon. Then
> suddenly to following appeared in the kernel log and the whole system hung up.
> This log is also from an instant copy over SSH.
>
> Now I'm pl
Reflect the current status. Portions of the text taken from the
wiki pages.
Signed-off-by: David Sterba
---
Please enqueue for 3.13
fs/btrfs/Kconfig | 15 ++-
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
index f9d5094e1029..aa97
Two new options were added in 3.12: commit and rescan_uuid_tree
CC: linux-...@vger.kernel.org
Signed-off-by: David Sterba
---
Documentation/filesystems/btrfs.txt | 12 +++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/btrfs.txt
b/Documentation/
The tools mentioned have been obsoleted long ago, replace
with the current ones.
CC: linux-...@vger.kernel.org
Signed-off-by: David Sterba
---
Documentation/filesystems/btrfs.txt | 22 ++
1 file changed, 6 insertions(+), 16 deletions(-)
diff --git a/Documentation/filesystems
On Fri, Nov 15, 2013 at 07:25:34PM +0800, Anand Jain wrote:
> static int btrfs_scan_kernel(void *search)
> {
> - int ret = 0, fd;
> - FILE *f;
> - struct mntent *mnt;
> - struct btrfs_ioctl_fs_info_args fs_info_arg;
> - struct btrfs_ioctl_dev_info_args *dev_info_arg = NULL;
>
Hi,
I've been getting the error message "fs tree 264 refs 1 not found" when
running btrfsck (v0.19) after a test case. The test case creates and
then deletes a subvolume while concurrently creating a snapshot of the
parent directory. This situation occurred with kernel version 3.11.1.
Here's
On Tue, Nov 19, 2013 at 8:05 PM, Fengguang Wu wrote:
> On Tue, Nov 19, 2013 at 07:56:35PM -0800, Kees Cook wrote:
>> Hi!
>>
>> Which tree is 'devel-snb'? I don't see that on the kernel.org trees.
>
> It's my local merge branch, based on the latest upstream release.
Hm, which release? I don't see
Hi all -- no real comments, except as I mentioned to Ric, my tutorial in FAST
last February presents Reed-Solomon coding with Cauchy matrices, and then makes
special note of the common pitfall of assuming that you can append a
Vandermonde matrix to an identity matrix. Please see
http://web.eec
Hugo Mills posted on Wed, 20 Nov 2013 08:09:58 + as excerpted:
> RAID-0: min 2 devices
> RAID-10: min 4 devices
> RAID-5: min 2 devices (I think)
> RAID-6: min 3 devices (I think)
RAID-5 should be 3-device minimum (each stripe consisting of two data
segments and one parity segment, each o
On Wed, Nov 20, 2013 at 04:43:57PM +, Duncan wrote:
> Hugo Mills posted on Wed, 20 Nov 2013 08:09:58 + as excerpted:
>
> > RAID-0: min 2 devices
> > RAID-10: min 4 devices
> > RAID-5: min 2 devices (I think)
> > RAID-6: min 3 devices (I think)
>
> RAID-5 should be 3-device minimum (eac
Martin posted on Wed, 20 Nov 2013 06:51:20 + as excerpted:
> It's now gone back to a pattern from a full week ago:
>
> (gdb) bt #0 0x0042d576 in read_extent_buffer ()
> #1 0x0041ee79 in btrfs_check_node ()
> #2 0x00420211 in check_block ()
> #3 0x00420813 i
Pedro Fonseca posted on Wed, 20 Nov 2013 16:22:18 +0100 as excerpted:
> I've been getting the error message "fs tree 264 refs 1 not found" when
> running btrfsck (v0.19) after a test case. The test case creates and
> then deletes a subvolume while concurrently creating a snapshot of the
> parent d
Quoting Fengguang Wu (2013-11-19 23:05:51)
> On Tue, Nov 19, 2013 at 07:56:35PM -0800, Kees Cook wrote:
> > Hi!
> >
> > Which tree is 'devel-snb'? I don't see that on the kernel.org trees.
>
> It's my local merge branch, based on the latest upstream release.
>
> Let's CC the btrfs developers for
On 11/19/13, 11:07 AM, Filipe David Borba Manana wrote:
> From kmemleak:
>
> hex dump (first 32 bytes):
> 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> backtrace:
> [] kmemleak_alloc+0x26/0x50
On 11/20/13, 12:30 PM, Chris Mason wrote:
> Quoting Fengguang Wu (2013-11-19 23:05:51)
>> On Tue, Nov 19, 2013 at 07:56:35PM -0800, Kees Cook wrote:
>>> Hi!
>>>
>>> Which tree is 'devel-snb'? I don't see that on the kernel.org trees.
>>
>> It's my local merge branch, based on the latest upstream re
On Wed, Nov 20, 2013 at 2:31 AM, David Brown wrote:
> That's certainly a reasonable way to look at it. We should not limit
> the possibilities for high-end systems because of the limitations of
> low-end systems that are unlikely to use 3+ parity anyway. I've also
> looked up a list of the proce
Hi David,
>> The choice of ZFS to use powers of 4 was likely not optimal,
>> because to multiply by 4, it has to do two multiplications by 2.
> I can agree with that. I didn't copy ZFS's choice here
David, it was not my intention to suggest that you copied from ZFS.
Sorry to have expressed myself
On Wed, Nov 20, 2013 at 10:05 AM, Jeff Mahoney wrote:
> On 11/20/13, 12:30 PM, Chris Mason wrote:
>> Quoting Fengguang Wu (2013-11-19 23:05:51)
>>> On Tue, Nov 19, 2013 at 07:56:35PM -0800, Kees Cook wrote:
Hi!
Which tree is 'devel-snb'? I don't see that on the kernel.org trees.
>>>
It is also possible to quickly multiply by 2^-1 which makes for an interesting
R parity.
Andrea Mazzoleni wrote:
>Hi David,
>
>>> The choice of ZFS to use powers of 4 was likely not optimal,
>>> because to multiply by 4, it has to do two multiplications by 2.
>> I can agree with that. I didn't
Hi John,
Yes. There are still AMD CPUs sold without SSSE3. Most notably Athlon.
Instead, Intel is providing SSSE3 from the Core 2 Duo.
A detailed list is available at: http://en.wikipedia.org/wiki/SSSE3
Ciao,
Andrea
On Wed, Nov 20, 2013 at 7:09 PM, John Williams wrote:
> On Wed, Nov 20, 2013 a
Hi,
Yep. At present to multiply for 2^-1 I'm using in C:
static inline uint64_t d2_64(uint64_t v)
{
uint64_t mask = v & 0x0101010101010101U;
mask = (mask << 8) - mask;
v = (v >> 1) & 0x7f7f7f7f7f7f7f7fU;
v ^= mask & 0x8e8e8e8e8e8e8e8eU;
return v;
}
and for
On 11/20/2013 10:56 AM, Andrea Mazzoleni wrote:
> Hi,
>
> Yep. At present to multiply for 2^-1 I'm using in C:
>
> static inline uint64_t d2_64(uint64_t v)
> {
> uint64_t mask = v & 0x0101010101010101U;
> mask = (mask << 8) - mask;
> v = (v >> 1) & 0x7f7f7f7f7f7f7f7fU;
>
On 11/20/2013 10:56 AM, Andrea Mazzoleni wrote:
> Hi,
>
> Yep. At present to multiply for 2^-1 I'm using in C:
>
> static inline uint64_t d2_64(uint64_t v)
> {
> uint64_t mask = v & 0x0101010101010101U;
> mask = (mask << 8) - mask;
(mask << 7) I assume...
--
To unsubscribe from
Hi Jim,
I build the matrix in a way that results in coefficients matching
Linux RAID for the first two rows, and at the same time gives
the guarantee that all the square submatrices are not singular,
resulting in a MDS code.
I start forming a Cauchy matrix setting each element to 1/(xi+yj)
where
On 11/20/2013 11:05 AM, Andrea Mazzoleni wrote:
>
> For the first row with j=0, I use xi = 2^-i and y0 = 0, that results in:
>
How can xi = 2^-i if x is supposed to be constant?
That doesn't mean that your approach isn't valid, of course, but it
might not be a Cauchy matrix and thus needs addit
On 20/11/13 17:08, Duncan wrote:
> Martin posted on Wed, 20 Nov 2013 06:51:20 + as excerpted:
>
>> It's now gone back to a pattern from a full week ago:
>>
>> (gdb) bt #0 0x0042d576 in read_extent_buffer ()
>> #1 0x0041ee79 in btrfs_check_node ()
>> #2 0x00420211 in
On 20/11/13 17:08, Duncan wrote:
> Which leads to the question of what to do next. Obviously, there have
> been a number of update patches since then, some of which might address
> your problem. You could update your kernel and userspace and try
> again... /if/ you have the patience...
This
Dear list members,
When the kernel had paniced because of the key_search_validate() defrag bug,
on the next restart it started to recreate its space- and inode caches. Both
were finished in 5 minutes but when I tried to enter back to "init 3", the
kernel paniced and hung up again.
Versions:
-
Peter, I think I understand it differently. Concrete example in GF(256) for
k=6, m=4:
First, create a 3 by 6 cauchy matrix, using x_i = 2^-i, and y_i = 0 for i=0,
and y_i = 2^i for other i. In this case: x = { 1, 142, 71, 173, 216, 108 }
y = { 0, 2, 4). The cauchy matrix is:
1 2 4
On Wed, Nov 20, 2013 at 6:02 PM, Jeff Mahoney wrote:
> On 11/19/13, 11:07 AM, Filipe David Borba Manana wrote:
>> From kmemleak:
>>
>> hex dump (first 32 bytes):
>> 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 .
Hi Peter,
>> static inline uint64_t d2_64(uint64_t v)
>> {
>> uint64_t mask = v & 0x0101010101010101U;
>> mask = (mask << 8) - mask;
>
> (mask << 7) I assume...
No. It's "(mask << 8) - mask". We want to expand the bit at position 0
(in each byte) to the full byte, resulting in 0xFF
On 11/20/2013 01:04 PM, Andrea Mazzoleni wrote:
> Hi Peter,
>
>>> static inline uint64_t d2_64(uint64_t v)
>>> {
>>> uint64_t mask = v & 0x0101010101010101U;
>>> mask = (mask << 8) - mask;
>>
>> (mask << 7) I assume...
> No. It's "(mask << 8) - mask". We want to expand the bit at p
Hugo Mills posted on Wed, 20 Nov 2013 16:52:47 + as excerpted:
>> Perhaps it's time I get that wiki account and edit some of this stuff
>> myself...
>
>Do check the assumptions first. :)
Of course. =:^)
--
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lo
Hi Peter,
> Now, that doesn't sound like something that can get neatly meshed into
> the Cauchy matrix scheme, I assume.
You are correct. Multiplication by 2^-1 cannot be used for the Cauchy method.
I used it to implement an alternate triple parity not requiring PSHUFB
that I used as reference fo
Hi,
> First, create a 3 by 6 cauchy matrix, using x_i = 2^-i, and y_i = 0 for i=0,
> and y_i = 2^i for other i.
> In this case: x = { 1, 142, 71, 173, 216, 108 } y = { 0, 2, 4). The
> cauchy matrix is:
>
> 1 2 4 8 16 32
> 244 83 78 183 118 47
> 167 39 213 59 153 82
>
> Divide
On 11/20/2013 12:30 PM, James Plank wrote:
> Peter, I think I understand it differently. Concrete example in GF(256) for
> k=6, m=4:
>
> First, create a 3 by 6 cauchy matrix, using x_i = 2^-i, and y_i = 0 for i=0,
> and y_i = 2^i for other i. In this case: x = { 1, 142, 71, 173, 216, 108 }
Hi Piergiorgio,
> In RAID-6 (as per raid6check) there is an easy way
> to verify where an HDD has incorrect data.
> I suspect, for each 2 parity block it should be
> possible to find 1 error (and if this is true, then
> quad parity is more attractive than triple one).
Yes. The theory say that with
This patch fixes the following warnings:
fs/btrfs/extent-tree.c:6201:12: sparse: symbol 'get_raid_name' was not
declared. Should it be static?
fs/btrfs/extent-tree.c:8430:9: error: format not a string literal and no format
arguments [-Werror=format-security] get_raid_name(index));
Signed-off-by:
On Wed, Nov 20, 2013 at 11:44:39AM +0100, David Brown wrote:
[...]
> > In RAID-6 (as per raid6check) there is an easy way
> > to verify where an HDD has incorrect data.
> >
>
> I think the way to do that is just to generate the parity blocks from
> the data blocks, and compare them to the existin
Filipe noticed that we were leaking the features attribute group
after umount. His fix of just calling sysfs_remove_group() wasn't enough
since that removes just the supported features and not the unknown
features (but a regular test wouldn't show that).
This patch changes the unknown feature hand
On Wed, Nov 20, 2013 at 1:50 PM, Jeff Mahoney wrote:
> This patch fixes the following warnings:
> fs/btrfs/extent-tree.c:6201:12: sparse: symbol 'get_raid_name' was not
> declared. Should it be static?
> fs/btrfs/extent-tree.c:8430:9: error: format not a string literal and no
> format arguments
On Mon, Nov 18, 2013 at 11:08:59PM +0100, Andrea Mazzoleni wrote:
[...]
I've a side question, a bit OT, but maybe you
could help with the answer.
How about par2? How does this work?
They claim "Vendermonde" matrix and they seem
to be quite flexible in amount of parities.
The could be in GF(2^16),
On Wed, Nov 20, 2013 at 08:04:58AM -0800, Kees Cook wrote:
> On Tue, Nov 19, 2013 at 8:05 PM, Fengguang Wu wrote:
> > On Tue, Nov 19, 2013 at 07:56:35PM -0800, Kees Cook wrote:
> >> Hi!
> >>
> >> Which tree is 'devel-snb'? I don't see that on the kernel.org trees.
> >
> > It's my local merge branc
On 11/20/2013 10:16 AM, James Plank wrote:
> Hi all -- no real comments, except as I mentioned to Ric, my tutorial
> in FAST last February presents Reed-Solomon coding with Cauchy
> matrices, and then makes special note of the common pitfall of
> assuming that you can append a Vandermonde matrix to
For myself or any machines I managed for work that do not need high
IOPS, I would definitely choose triple- or quad-parity over RAID 51 or
similar schemes with arrays of 16 - 32 drives.
No need to go into detail here on a subject Adam Leventhal has already
covered in detail in an article "Triple-P
as of now with out this patch user would see
fsinfo per btrfs mount path but which mean multiple
entry if more than one subvol is mounted of the same
fsid. so this patch will handle that nicely.
Signed-off-by: Anand Jain
---
v5: fixup missed mem free, thanks David
v4: rebase on integration-20131
On 11/20/2013 10:18 PM, David Sterba wrote:
On Fri, Nov 15, 2013 at 07:25:34PM +0800, Anand Jain wrote:
static int btrfs_scan_kernel(void *search)
{
- int ret = 0, fd;
- FILE *f;
- struct mntent *mnt;
- struct btrfs_ioctl_fs_info_args fs_info_arg;
- struct btr
On 11/20/2013 12:44 PM, Andrea Mazzoleni wrote:
> Yes. There are still AMD CPUs sold without SSSE3. Most notably Athlon.
> Instead, Intel is providing SSSE3 from the Core 2 Duo.
I hate branding discontinuity, due to the resulting confusion...
Athlon, Athlon64, Athlon64 X2, Athlon X2 (K10), Athlo
On 11/20/2013 8:46 PM, John Williams wrote:
> For myself or any machines I managed for work that do not need high
> IOPS, I would definitely choose triple- or quad-parity over RAID 51 or
> similar schemes with arrays of 16 - 32 drives.
You must see a week long rebuild as acceptable...
> No need t
On Wed, Nov 20, 2013 at 10:52 PM, Stan Hoeppner wrote:
> On 11/20/2013 8:46 PM, John Williams wrote:
>> For myself or any machines I managed for work that do not need high
>> IOPS, I would definitely choose triple- or quad-parity over RAID 51 or
>> similar schemes with arrays of 16 - 32 drives.
>
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