| Message ID | 59ebcf23-9e32-e219-ef8b-9aa7ab2444c2@redhat.com (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Headers | show |
| Series | mkfs.xfs.8: clarify DAX-vs-reflink restrictions in the mkfs.xfs man page | expand |
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>
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
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 >
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
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
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> ---