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* [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page
@ 2021-08-27 15:39 Eric Sandeen
  2021-08-27 15:46 ` Bill O'Donnell
  2021-08-27 15:49 ` Darrick J. Wong
  0 siblings, 2 replies; 5+ messages in thread
From: Eric Sandeen @ 2021-08-27 15:39 UTC (permalink / raw)
  To: xfs; +Cc: Bill O'Donnell

Now that we have the tristate dax mount options, it is possible
to enable DAX mode for non-reflinked files on a reflink-capable
filesystem.  Clarify this in the mkfs.xfs manpage.

Reported-by: Bill O'Donnell <bodonnel@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/man/man8/mkfs.xfs.8 b/man/man8/mkfs.xfs.8
index a7f70285..84ac50e8 100644
--- a/man/man8/mkfs.xfs.8
+++ b/man/man8/mkfs.xfs.8
@@ -316,12 +316,20 @@ option set. When the option
  is used, the reference count btree feature is not supported and reflink is
  disabled.
  .IP
-Note: the filesystem DAX mount option (
+Note: the filesystem-wide DAX mount options (
  .B \-o dax
-) is incompatible with
-reflink-enabled XFS filesystems.  To use filesystem DAX with XFS, specify the
+and
+.B \-o dax=always
+) are incompatible with
+reflink-enabled XFS filesystems.  To use filesystem-wide DAX with XFS, specify the
  .B \-m reflink=0
  option to mkfs.xfs to disable the reflink feature.
+Alternatey, use the
+.B \-o dax=inode
+mount option to selectively enable DAX mode on non-reflinked files.
+See
+.BR xfs (5)
+for more information.
  .RE
  .PP
  .PD 0


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page
  2021-08-27 15:39 [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page Eric Sandeen
@ 2021-08-27 15:46 ` Bill O'Donnell
  2021-08-27 15:47   ` Eric Sandeen
  2021-08-27 15:49 ` Darrick J. Wong
  1 sibling, 1 reply; 5+ messages in thread
From: Bill O'Donnell @ 2021-08-27 15:46 UTC (permalink / raw)
  To: Eric Sandeen; +Cc: xfs, Bill O'Donnell

On Fri, Aug 27, 2021 at 10:39:18AM -0500, Eric Sandeen wrote:
> Now that we have the tristate dax mount options, it is possible
> to enable DAX mode for non-reflinked files on a reflink-capable
> filesystem.  Clarify this in the mkfs.xfs manpage.
> 
> Reported-by: Bill O'Donnell <bodonnel@redhat.com>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> diff --git a/man/man8/mkfs.xfs.8 b/man/man8/mkfs.xfs.8
> index a7f70285..84ac50e8 100644
> --- a/man/man8/mkfs.xfs.8
> +++ b/man/man8/mkfs.xfs.8
> @@ -316,12 +316,20 @@ option set. When the option
>  is used, the reference count btree feature is not supported and reflink is
>  disabled.
>  .IP
> -Note: the filesystem DAX mount option (
> +Note: the filesystem-wide DAX mount options (
>  .B \-o dax
> -) is incompatible with
> -reflink-enabled XFS filesystems.  To use filesystem DAX with XFS, specify the
> +and
> +.B \-o dax=always
> +) are incompatible with
> +reflink-enabled XFS filesystems.  To use filesystem-wide DAX with XFS, specify the
>  .B \-m reflink=0
>  option to mkfs.xfs to disable the reflink feature.
> +Alternatey, use the
s /Alternatey/Alternately

> +.B \-o dax=inode
> +mount option to selectively enable DAX mode on non-reflinked files.
> +See
> +.BR xfs (5)
> +for more information.
>  .RE
>  .PP
>  .PD 0
> 

Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page
  2021-08-27 15:46 ` Bill O'Donnell
@ 2021-08-27 15:47   ` Eric Sandeen
  0 siblings, 0 replies; 5+ messages in thread
From: Eric Sandeen @ 2021-08-27 15:47 UTC (permalink / raw)
  To: Bill O'Donnell, Eric Sandeen; +Cc: xfs, Bill O'Donnell

On 8/27/21 10:46 AM, Bill O'Donnell wrote:
> On Fri, Aug 27, 2021 at 10:39:18AM -0500, Eric Sandeen wrote:


>> +and
>> +.B \-o dax=always
>> +) are incompatible with
>> +reflink-enabled XFS filesystems.  To use filesystem-wide DAX with XFS, specify the
>>   .B \-m reflink=0
>>   option to mkfs.xfs to disable the reflink feature.
>> +Alternatey, use the
> s /Alternatey/Alternately

Doh! Thanks.


-Eric

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page
  2021-08-27 15:39 [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page Eric Sandeen
  2021-08-27 15:46 ` Bill O'Donnell
@ 2021-08-27 15:49 ` Darrick J. Wong
  2021-08-27 16:23   ` Eric Sandeen
  1 sibling, 1 reply; 5+ messages in thread
From: Darrick J. Wong @ 2021-08-27 15:49 UTC (permalink / raw)
  To: Eric Sandeen; +Cc: xfs, Bill O'Donnell

On Fri, Aug 27, 2021 at 10:39:18AM -0500, Eric Sandeen wrote:
> Now that we have the tristate dax mount options, it is possible
> to enable DAX mode for non-reflinked files on a reflink-capable
> filesystem.  Clarify this in the mkfs.xfs manpage.
> 
> Reported-by: Bill O'Donnell <bodonnel@redhat.com>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> diff --git a/man/man8/mkfs.xfs.8 b/man/man8/mkfs.xfs.8
> index a7f70285..84ac50e8 100644
> --- a/man/man8/mkfs.xfs.8
> +++ b/man/man8/mkfs.xfs.8
> @@ -316,12 +316,20 @@ option set. When the option
>  is used, the reference count btree feature is not supported and reflink is
>  disabled.
>  .IP
> -Note: the filesystem DAX mount option (
> +Note: the filesystem-wide DAX mount options (
>  .B \-o dax
> -) is incompatible with
> -reflink-enabled XFS filesystems.  To use filesystem DAX with XFS, specify the
> +and
> +.B \-o dax=always
> +) are incompatible with
> +reflink-enabled XFS filesystems.  To use filesystem-wide DAX with XFS, specify the
>  .B \-m reflink=0
>  option to mkfs.xfs to disable the reflink feature.
> +Alternatey, use the

"Alternately..."

> +.B \-o dax=inode
> +mount option to selectively enable DAX mode on non-reflinked files.

/me wonders if this is dangerously close to wading into the muck that is
"Use dax=inode or even no dax option at all, then make sure nobody
shares your file's data blocks to set the DAX fsxattr flag on the file,
and /then/ you can have DAX."

<shrug> But the only blocker I can see is the misspelling above.

--D

> +See
> +.BR xfs (5)
> +for more information.
>  .RE
>  .PP
>  .PD 0
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page
  2021-08-27 15:49 ` Darrick J. Wong
@ 2021-08-27 16:23   ` Eric Sandeen
  0 siblings, 0 replies; 5+ messages in thread
From: Eric Sandeen @ 2021-08-27 16:23 UTC (permalink / raw)
  To: Darrick J. Wong, Eric Sandeen; +Cc: xfs, Bill O'Donnell

On 8/27/21 10:49 AM, Darrick J. Wong wrote:
> On Fri, Aug 27, 2021 at 10:39:18AM -0500, Eric Sandeen wrote:
>> Now that we have the tristate dax mount options, it is possible
>> to enable DAX mode for non-reflinked files on a reflink-capable
>> filesystem.  Clarify this in the mkfs.xfs manpage.
>>
>> Reported-by: Bill O'Donnell <bodonnel@redhat.com>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> diff --git a/man/man8/mkfs.xfs.8 b/man/man8/mkfs.xfs.8
>> index a7f70285..84ac50e8 100644
>> --- a/man/man8/mkfs.xfs.8
>> +++ b/man/man8/mkfs.xfs.8
>> @@ -316,12 +316,20 @@ option set. When the option
>>   is used, the reference count btree feature is not supported and reflink is
>>   disabled.
>>   .IP
>> -Note: the filesystem DAX mount option (
>> +Note: the filesystem-wide DAX mount options (
>>   .B \-o dax
>> -) is incompatible with
>> -reflink-enabled XFS filesystems.  To use filesystem DAX with XFS, specify the
>> +and
>> +.B \-o dax=always
>> +) are incompatible with
>> +reflink-enabled XFS filesystems.  To use filesystem-wide DAX with XFS, specify the
>>   .B \-m reflink=0
>>   option to mkfs.xfs to disable the reflink feature.
>> +Alternatey, use the
> 
> "Alternately..."

"Alternatively,"

> 
>> +.B \-o dax=inode
>> +mount option to selectively enable DAX mode on non-reflinked files.
> 
> /me wonders if this is dangerously close to wading into the muck that is
> "Use dax=inode or even no dax option at all, then make sure nobody
> shares your file's data blocks to set the DAX fsxattr flag on the file,
> and /then/ you can have DAX."

Perhaps I should drop most of it, and just wave hands vaguely at xfs.5?

-Eric

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-08-27 16:23 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-27 15:39 [PATCH] mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page Eric Sandeen
2021-08-27 15:46 ` Bill O'Donnell
2021-08-27 15:47   ` Eric Sandeen
2021-08-27 15:49 ` Darrick J. Wong
2021-08-27 16:23   ` Eric Sandeen

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