Re: [PATCH v2] chattr/lsattr: Support dax attribute

[Xiao Yang <yangx.jy@xxxxxxxxxxxxxx>]

Hi,

Ping :-)

Best Regards,
Xiao Yang
On 2020/8/28 16:22, Andreas Dilger wrote:
> On Aug 27, 2020, at 7:33 PM, Xiao Yang<yangx.jy@xxxxxxxxxxxxxx>  wrote:
> > Hi,
> >
> > Is there any comment on the patch? :-)
> I don't need a v3 for the Dax vs. DAX case, though I think DAX would be
> better.  The decision is up to Ted.
>
> Cheers, Andreas
>
> > Thanks,
> > Xiao Yang
> > On 2020/8/13 9:42, Xiao Yang wrote:
> > > On 2020/8/13 7:29, Andreas Dilger wrote:
> > > > On Jul 27, 2020, at 11:33 PM, Xiao Yang<yangx.jy@xxxxxxxxxxxxxx>   wrote:
> > > > > Use the letter 'x' to set/get dax attribute on a directory/file.
> > > > >
> > > > > Signed-off-by: Xiao Yang<yangx.jy@xxxxxxxxxxxxxx>
> > > > One minor nit below, but otherwise looks OK.
> > > >
> > > > Reviewed-by: Andreas Dilger<adilger@xxxxxxxxx>
> > > >
> > > > > diff --git a/lib/e2p/pf.c b/lib/e2p/pf.c
> > > > > index 0c6998c4..e59cccff 100644
> > > > > --- a/lib/e2p/pf.c
> > > > > +++ b/lib/e2p/pf.c
> > > > > @@ -44,6 +44,7 @@ static struct flags_name flags_array[] = {
> > > > >     { EXT2_TOPDIR_FL, "T", "Top_of_Directory_Hierarchies" },
> > > > >     { EXT4_EXTENTS_FL, "e", "Extents" },
> > > > >     { FS_NOCOW_FL, "C", "No_COW" },
> > > > > +    { FS_DAX_FL, "x", "Dax" },
> > > > Should this be "DAX" ?  That is how it is commonly used in the kernel.
> > > Hi Andreas,
> > >
> > > Thanks a lot for your review.
> > >
> > > Either 'Dax' or 'DAX' is fine to me because it is just the output of lsattr -v.
> > > For example, xfs_io shows 'dax' instead of 'DAX':
> > > # xfs_io -c "lsattr -v" file
> > > [dax] file
> > >
> > > BTW:
> > > I just used 'Dax' to follow the current format of output(i.e. capitalize the first letter).
> > >
> > > Do you want me to send v3 patch with the 'DAX'? :-)
> > >
> > > Best Regards,
> > > Xiao Yang
> > > > >     { EXT4_CASEFOLD_FL, "F", "Casefold" },
> > > > >     { EXT4_INLINE_DATA_FL, "N", "Inline_Data" },
> > > > >     { EXT4_PROJINHERIT_FL, "P", "Project_Hierarchy" },
> > > > > diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
> > > > > index 6c20ea77..88f510a3 100644
> > > > > --- a/lib/ext2fs/ext2_fs.h
> > > > > +++ b/lib/ext2fs/ext2_fs.h
> > > > > @@ -335,6 +335,7 @@ struct ext2_dx_tail {
> > > > > /* EXT4_EOFBLOCKS_FL 0x00400000 was here */
> > > > > #define FS_NOCOW_FL            0x00800000 /* Do not cow file */
> > > > > #define EXT4_SNAPFILE_FL        0x01000000  /* Inode is a snapshot */
> > > > > +#define FS_DAX_FL            0x02000000 /* Inode is DAX */
> > > > > #define EXT4_SNAPFILE_DELETED_FL    0x04000000  /* Snapshot is being deleted */
> > > > > #define EXT4_SNAPFILE_SHRUNK_FL        0x08000000  /* Snapshot shrink has completed */
> > > > > #define EXT4_INLINE_DATA_FL        0x10000000 /* Inode has inline data */
> > > > > diff --git a/misc/chattr.1.in b/misc/chattr.1.in
> > > > > index ff2fcf00..5a4928a5 100644
> > > > > --- a/misc/chattr.1.in
> > > > > +++ b/misc/chattr.1.in
> > > > > @@ -23,13 +23,13 @@ chattr \- change file attributes on a Linux file system
> > > > > .B chattr
> > > > > changes the file attributes on a Linux file system.
> > > > > .PP
> > > > > -The format of a symbolic mode is +-=[aAcCdDeFijPsStTu].
> > > > > +The format of a symbolic mode is +-=[aAcCdDeFijPsStTux].
> > > > > .PP
> > > > > The operator '+' causes the selected attributes to be added to the
> > > > > existing attributes of the files; '-' causes them to be removed; and '='
> > > > > causes them to be the only attributes that the files have.
> > > > > .PP
> > > > > -The letters 'aAcCdDeFijPsStTu' select the new attributes for the files:
> > > > > +The letters 'aAcCdDeFijPsStTux' select the new attributes for the files:
> > > > > append only (a),
> > > > > no atime updates (A),
> > > > > compressed (c),
> > > > > @@ -45,7 +45,8 @@ secure deletion (s),
> > > > > synchronous updates (S),
> > > > > no tail-merging (t),
> > > > > top of directory hierarchy (T),
> > > > > -and undeletable (u).
> > > > > +undeletable (u),
> > > > > +and direct access for files (x).
> > > > > .PP
> > > > > The following attributes are read-only, and may be listed by
> > > > > .BR lsattr (1)
> > > > > @@ -210,6 +211,14 @@ saved.  This allows the user to ask for its undeletion.  Note: please
> > > > > make sure to read the bugs and limitations section at the end of this
> > > > > document.
> > > > > .TP
> > > > > +.B x
> > > > > +The 'x' attribute can be set on a directory or file.  If the attribute
> > > > > +is set on an existing directory, it will be inherited by all files and
> > > > > +subdirectories that are subsequently created in the directory.  If an
> > > > > +existing directory has contained some files and subdirectories, modifying
> > > > > +the attribute on the parent directory doesn't change the attributes on
> > > > > +these files and subdirectories.
> > > > > +.TP
> > > > > .B V
> > > > > A file with the 'V' attribute set has fs-verity enabled.  It cannot be
> > > > > written to, and the filesystem will automatically verify all data read
> > > > > diff --git a/misc/chattr.c b/misc/chattr.c
> > > > > index a5d60170..c0337f86 100644
> > > > > --- a/misc/chattr.c
> > > > > +++ b/misc/chattr.c
> > > > > @@ -86,7 +86,7 @@ static unsigned long sf;
> > > > > static void usage(void)
> > > > > {
> > > > >     fprintf(stderr,
> > > > > -        _("Usage: %s [-pRVf] [-+=aAcCdDeijPsStTuF] [-v version] files...\n"),
> > > > > +        _("Usage: %s [-pRVf] [-+=aAcCdDeijPsStTuFx] [-v version] files...\n"),
> > > > >         program_name);
> > > > >     exit(1);
> > > > > }
> > > > > @@ -112,6 +112,7 @@ static const struct flags_char flags_array[] = {
> > > > >     { EXT2_NOTAIL_FL, 't' },
> > > > >     { EXT2_TOPDIR_FL, 'T' },
> > > > >     { FS_NOCOW_FL, 'C' },
> > > > > +    { FS_DAX_FL, 'x' },
> > > > >     { EXT4_CASEFOLD_FL, 'F' },
> > > > >     { 0, 0 }
> > > > > };
> > > > > --
> > > > > 2.21.0
> > > > Cheers, Andreas
>
> Cheers, Andreas