[PATCH 0/2] squashfs: support linear addressing

[PATCH 0/2] squashfs: support linear addressing

[UCHINO Satoshi]

This patchset enables the SquashFS driver to load data directly from a
linear adressed memory range (usually non volatile memory like flash)
instead of going through the block device layer.  This saves some
memory since no intermediate buffering is necessary.

The location of the SquashFs image need to be specified by using the
physaddr=0x******** mount option.
For example,
  mount -t squashfs_linear -o physaddr=0x100000 none /mnt

In addition, the linear SquashFS image can be used as a root file
system.  To actually have the kernel mount this SquashFS image as a
root file system, you must also pass the command line parameter
"root=/dev/null", "rootfstype=squashfs_linear", and
"rootflags=physaddr=0x********" to the kernel (replace 0x******** with
the physical address location of the linear SquashFs image to boot
with).

UCHINO Satoshi (2):
  squashfs: add an extra argument to decompress callback
  squashfs: support linear addressing

 fs/squashfs/Kconfig          |   25 +++++++
 fs/squashfs/block.c          |   72 ++++++++++++++++++---
 fs/squashfs/decompressor.h   |    6 +-
 fs/squashfs/inode.c          |   10 +++
 fs/squashfs/lzo_wrapper.c    |   12 +++-
 fs/squashfs/squashfs.h       |    5 ++
 fs/squashfs/squashfs_fs_sb.h |    2 +
 fs/squashfs/super.c          |  144 +++++++++++++++++++++++++++++++++++++++---
 fs/squashfs/xz_wrapper.c     |    7 ++-
 fs/squashfs/zlib_wrapper.c   |    7 ++-
 10 files changed, 265 insertions(+), 25 deletions(-)

Re: [PATCH 0/2] squashfs: support linear addressing

[Vyacheslav Dubeyko]

Hi,

Could you please describe in more details advantages of your patchset?
Do you have any benchmark results?

With the best regards,
Vyacheslav Dubeyko.

On Tue, 2012-05-15 at 20:33 +0900, UCHINO Satoshi wrote:
> This patchset enables the SquashFS driver to load data directly from a
> linear adressed memory range (usually non volatile memory like flash)
> instead of going through the block device layer.  This saves some
> memory since no intermediate buffering is necessary.
> 
> The location of the SquashFs image need to be specified by using the
> physaddr=0x******** mount option.
> For example,
>   mount -t squashfs_linear -o physaddr=0x100000 none /mnt
> 
> In addition, the linear SquashFS image can be used as a root file
> system.  To actually have the kernel mount this SquashFS image as a
> root file system, you must also pass the command line parameter
> "root=/dev/null", "rootfstype=squashfs_linear", and
> "rootflags=physaddr=0x********" to the kernel (replace 0x******** with
> the physical address location of the linear SquashFs image to boot
> with).
> 
> UCHINO Satoshi (2):
>   squashfs: add an extra argument to decompress callback
>   squashfs: support linear addressing
> 
>  fs/squashfs/Kconfig          |   25 +++++++
>  fs/squashfs/block.c          |   72 ++++++++++++++++++---
>  fs/squashfs/decompressor.h   |    6 +-
>  fs/squashfs/inode.c          |   10 +++
>  fs/squashfs/lzo_wrapper.c    |   12 +++-
>  fs/squashfs/squashfs.h       |    5 ++
>  fs/squashfs/squashfs_fs_sb.h |    2 +
>  fs/squashfs/super.c          |  144 +++++++++++++++++++++++++++++++++++++++---
>  fs/squashfs/xz_wrapper.c     |    7 ++-
>  fs/squashfs/zlib_wrapper.c   |    7 ++-
>  10 files changed, 265 insertions(+), 25 deletions(-)
> --
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> the body of a message to majordomo@vger.kernel.org
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Re: [PATCH 0/2] squashfs: support linear addressing

[Vyacheslav Dubeyko]

Hi,

By the way, what about reliability of your solution? I mean possible
bit-flips, bad blocks in the case of "pure" NAND. Maybe, I am not fully
familiarize with your solution but I worry about reliability issues.

And what about MTD layer API? Why do you not use MTD layer in your
solution?

With the best regards,
Vyacheslav Dubeyko.


On Tue, 2012-05-15 at 20:33 +0900, UCHINO Satoshi wrote:
> This patchset enables the SquashFS driver to load data directly from a
> linear adressed memory range (usually non volatile memory like flash)
> instead of going through the block device layer.  This saves some
> memory since no intermediate buffering is necessary.
> 
> The location of the SquashFs image need to be specified by using the
> physaddr=0x******** mount option.
> For example,
>   mount -t squashfs_linear -o physaddr=0x100000 none /mnt
> 
> In addition, the linear SquashFS image can be used as a root file
> system.  To actually have the kernel mount this SquashFS image as a
> root file system, you must also pass the command line parameter
> "root=/dev/null", "rootfstype=squashfs_linear", and
> "rootflags=physaddr=0x********" to the kernel (replace 0x******** with
> the physical address location of the linear SquashFs image to boot
> with).
> 
> UCHINO Satoshi (2):
>   squashfs: add an extra argument to decompress callback
>   squashfs: support linear addressing
> 
>  fs/squashfs/Kconfig          |   25 +++++++
>  fs/squashfs/block.c          |   72 ++++++++++++++++++---
>  fs/squashfs/decompressor.h   |    6 +-
>  fs/squashfs/inode.c          |   10 +++
>  fs/squashfs/lzo_wrapper.c    |   12 +++-
>  fs/squashfs/squashfs.h       |    5 ++
>  fs/squashfs/squashfs_fs_sb.h |    2 +
>  fs/squashfs/super.c          |  144 +++++++++++++++++++++++++++++++++++++++---
>  fs/squashfs/xz_wrapper.c     |    7 ++-
>  fs/squashfs/zlib_wrapper.c   |    7 ++-
>  10 files changed, 265 insertions(+), 25 deletions(-)
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH 0/2] squashfs: support linear addressing

[UCHINO Satoshi]

Hi,

On Tue, 15 May 2012 22:02:22 +0900, "Vyacheslav Dubeyko" <slava@dubeyko.com> wrote:
> Hi,
> 
> Could you please describe in more details advantages of your patchset?
> Do you have any benchmark results?

Though this is quite old material (6 years old :), 
here is our presentation material at CELF Japan Jamboree #6.
(http://tree.celinuxforum.org/CelfPubWiki/JapanTechnicalJamboree6)

(Slide in Japanese)
http://tree.celinuxforum.org/CelfPubWiki/JapanTechnicalJamboree6?action=AttachFile&do=view&target=squashfs_jpn.pdf

(English translation)
http://tree.celinuxforum.org/CelfPubWiki/JapanTechnicalJamboree6?action=AttachFile&do=view&target=squashfs_eng.pdf

See pages 12-15 in particular.

In this benchmark, we copied initrd image to ram disk.
Now, we probably have better way to do so and performance improvement
will get much smaller.

However, for the use case of mounting image in arbitrary physical
address range, we believe this solution is much more straightfoward
than using block devices.

Best regards,
  UCHINO Satoshi


> On Tue, 2012-05-15 at 20:33 +0900, UCHINO Satoshi wrote:
>> This patchset enables the SquashFS driver to load data directly from a
>> linear adressed memory range (usually non volatile memory like flash)
>> instead of going through the block device layer.  This saves some
>> memory since no intermediate buffering is necessary.
>>
>> The location of the SquashFs image need to be specified by using the
>> physaddr=0x******** mount option.
>> For example,
>>   mount -t squashfs_linear -o physaddr=0x100000 none /mnt
>>
>> In addition, the linear SquashFS image can be used as a root file
>> system.  To actually have the kernel mount this SquashFS image as a
>> root file system, you must also pass the command line parameter
>> "root=/dev/null", "rootfstype=squashfs_linear", and
>> "rootflags=physaddr=0x********" to the kernel (replace 0x******** with
>> the physical address location of the linear SquashFs image to boot
>> with).
>>
>> UCHINO Satoshi (2):
>>   squashfs: add an extra argument to decompress callback
>>   squashfs: support linear addressing
>>
>>  fs/squashfs/Kconfig          |   25 +++++++
>>  fs/squashfs/block.c          |   72 ++++++++++++++++++---
>>  fs/squashfs/decompressor.h   |    6 +-
>>  fs/squashfs/inode.c          |   10 +++
>>  fs/squashfs/lzo_wrapper.c    |   12 +++-
>>  fs/squashfs/squashfs.h       |    5 ++
>>  fs/squashfs/squashfs_fs_sb.h |    2 +
>>  fs/squashfs/super.c          |  144 
>> +++++++++++++++++++++++++++++++++++++++---
>>  fs/squashfs/xz_wrapper.c     |    7 ++-
>>  fs/squashfs/zlib_wrapper.c   |    7 ++-
>>  10 files changed, 265 insertions(+), 25 deletions(-)

Re: [PATCH 0/2] squashfs: support linear addressing

[UCHINO Satoshi]

Hi,
On Wed, 16 May 2012 15:09:23 +0900, "Vyacheslav Dubeyko" <slava@dubeyko.com> wrote:
> By the way, what about reliability of your solution? I mean possible
> bit-flips, bad blocks in the case of "pure" NAND. Maybe, I am not fully
> familiarize with your solution but I worry about reliability issues.
> And what about MTD layer API? Why do you not use MTD layer in your
> solution?

To mount squashfs images in raw NAND flashes, as you suggested, we
should use UBI, etc. to handle bad block management.
BTW, I guess raw NAND flashes are not linearly accessible.

What we are assuming is devices which can be directly accessed by
physical addresses, such as RAM, NOR flashes, etc.

Best regards,
  UCHINO Satoshi

> On Tue, 2012-05-15 at 20:33 +0900, UCHINO Satoshi wrote:
>> This patchset enables the SquashFS driver to load data directly from a
>> linear adressed memory range (usually non volatile memory like flash)
>> instead of going through the block device layer.  This saves some
>> memory since no intermediate buffering is necessary.
>>
>> The location of the SquashFs image need to be specified by using the
>> physaddr=0x******** mount option.
>> For example,
>>   mount -t squashfs_linear -o physaddr=0x100000 none /mnt
>>
>> In addition, the linear SquashFS image can be used as a root file
>> system.  To actually have the kernel mount this SquashFS image as a
>> root file system, you must also pass the command line parameter
>> "root=/dev/null", "rootfstype=squashfs_linear", and
>> "rootflags=physaddr=0x********" to the kernel (replace 0x******** with
>> the physical address location of the linear SquashFs image to boot
>> with).
>>
>> UCHINO Satoshi (2):
>>   squashfs: add an extra argument to decompress callback
>>   squashfs: support linear addressing
>>
>>  fs/squashfs/Kconfig          |   25 +++++++
>>  fs/squashfs/block.c          |   72 ++++++++++++++++++---
>>  fs/squashfs/decompressor.h   |    6 +-
>>  fs/squashfs/inode.c          |   10 +++
>>  fs/squashfs/lzo_wrapper.c    |   12 +++-
>>  fs/squashfs/squashfs.h       |    5 ++
>>  fs/squashfs/squashfs_fs_sb.h |    2 +
>>  fs/squashfs/super.c          |  144 
>> +++++++++++++++++++++++++++++++++++++++---
>>  fs/squashfs/xz_wrapper.c     |    7 ++-
>>  fs/squashfs/zlib_wrapper.c   |    7 ++-
>>  10 files changed, 265 insertions(+), 25 deletions(-)