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* [PATCH] mke2fs.8: Improve valid block size documentation
@ 2020-10-13 13:38 Jan Kara
  2020-10-15  0:56 ` Andreas Dilger
  0 siblings, 1 reply; 3+ messages in thread
From: Jan Kara @ 2020-10-13 13:38 UTC (permalink / raw)
  To: Ted Tso; +Cc: linux-ext4, Jan Kara

Explain which valid block sizes mke2fs supports in more detail.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 misc/mke2fs.8.in | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
index e6bfc6d6fd2d..0814d216f3a4 100644
--- a/misc/mke2fs.8.in
+++ b/misc/mke2fs.8.in
@@ -207,10 +207,11 @@ manual page for more details.
 .SH OPTIONS
 .TP
 .BI \-b " block-size"
-Specify the size of blocks in bytes.  Valid block-size values are 1024,
-2048 and 4096 bytes per block.  If omitted,
-block-size is heuristically determined by the filesystem size and
-the expected usage of the filesystem (see the
+Specify the size of blocks in bytes.  Valid block-size values are powers of two
+from 1024 up to 65536 (however note that the kernel is able to mount only
+filesystems with block-size smaller or equal to the system page size - 4k on
+x86 systems). If omitted, block-size is heuristically determined by the
+filesystem size and the expected usage of the filesystem (see the
 .B \-T
 option).  If
 .I block-size
-- 
2.16.4


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] mke2fs.8: Improve valid block size documentation
  2020-10-13 13:38 [PATCH] mke2fs.8: Improve valid block size documentation Jan Kara
@ 2020-10-15  0:56 ` Andreas Dilger
  2020-10-15  9:27   ` Jan Kara
  0 siblings, 1 reply; 3+ messages in thread
From: Andreas Dilger @ 2020-10-15  0:56 UTC (permalink / raw)
  To: Jan Kara; +Cc: Ted Tso, linux-ext4


[-- Attachment #1: Type: text/plain, Size: 1505 bytes --]

On Oct 13, 2020, at 7:38 AM, Jan Kara <jack@suse.cz> wrote:
> 
> Explain which valid block sizes mke2fs supports in more detail.
> 
> Signed-off-by: Jan Kara <jack@suse.cz>

Should this mention that the default block size is 4096 bytes for most
filesystems?

It might mention e.g. ppc64 or aarch64 can use 64KB page size, but this
is definitely an improvement already.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>

> ---
> misc/mke2fs.8.in | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
> index e6bfc6d6fd2d..0814d216f3a4 100644
> --- a/misc/mke2fs.8.in
> +++ b/misc/mke2fs.8.in
> @@ -207,10 +207,11 @@ manual page for more details.
> .SH OPTIONS
> .TP
> .BI \-b " block-size"
> -Specify the size of blocks in bytes.  Valid block-size values are 1024,
> -2048 and 4096 bytes per block.  If omitted,
> -block-size is heuristically determined by the filesystem size and
> -the expected usage of the filesystem (see the
> +Specify the size of blocks in bytes.  Valid block-size values are powers of two
> +from 1024 up to 65536 (however note that the kernel is able to mount only
> +filesystems with block-size smaller or equal to the system page size - 4k on
> +x86 systems). If omitted, block-size is heuristically determined by the
> +filesystem size and the expected usage of the filesystem (see the
> .B \-T
> option).  If
> .I block-size
> --
> 2.16.4
> 


Cheers, Andreas






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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] mke2fs.8: Improve valid block size documentation
  2020-10-15  0:56 ` Andreas Dilger
@ 2020-10-15  9:27   ` Jan Kara
  0 siblings, 0 replies; 3+ messages in thread
From: Jan Kara @ 2020-10-15  9:27 UTC (permalink / raw)
  To: Andreas Dilger; +Cc: Jan Kara, Ted Tso, linux-ext4

On Wed 14-10-20 18:56:13, Andreas Dilger wrote:
> On Oct 13, 2020, at 7:38 AM, Jan Kara <jack@suse.cz> wrote:
> > 
> > Explain which valid block sizes mke2fs supports in more detail.
> > 
> > Signed-off-by: Jan Kara <jack@suse.cz>
> 
> Should this mention that the default block size is 4096 bytes for most
> filesystems?

That would be to the "heuristic" parts. Yes, I agree, I'll add that.

> It might mention e.g. ppc64 or aarch64 can use 64KB page size, but this
> is definitely an improvement already.

Yeah, I can add that to the "page size" part. But with these archs there's
a catch that page size can be configured in the kernel config so the
formulation will need to be a bit more careful. But I'll add something.

> Reviewed-by: Andreas Dilger <adilger@dilger.ca>

Thanks! I'll send v2.

								Honza
> 
> > ---
> > misc/mke2fs.8.in | 9 +++++----
> > 1 file changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
> > index e6bfc6d6fd2d..0814d216f3a4 100644
> > --- a/misc/mke2fs.8.in
> > +++ b/misc/mke2fs.8.in
> > @@ -207,10 +207,11 @@ manual page for more details.
> > .SH OPTIONS
> > .TP
> > .BI \-b " block-size"
> > -Specify the size of blocks in bytes.  Valid block-size values are 1024,
> > -2048 and 4096 bytes per block.  If omitted,
> > -block-size is heuristically determined by the filesystem size and
> > -the expected usage of the filesystem (see the
> > +Specify the size of blocks in bytes.  Valid block-size values are powers of two
> > +from 1024 up to 65536 (however note that the kernel is able to mount only
> > +filesystems with block-size smaller or equal to the system page size - 4k on
> > +x86 systems). If omitted, block-size is heuristically determined by the
> > +filesystem size and the expected usage of the filesystem (see the
> > .B \-T
> > option).  If
> > .I block-size
> > --
> > 2.16.4
> > 
> 
> 
> Cheers, Andreas
> 
> 
> 
> 
> 


-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2020-10-13 13:38 [PATCH] mke2fs.8: Improve valid block size documentation Jan Kara
2020-10-15  0:56 ` Andreas Dilger
2020-10-15  9:27   ` Jan Kara

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