Date:   Thu, 17 Sep 2020 11:31:53 +0800
From:   Xiao Yang <yangx.jy@...fujitsu.com>
To:     Theodore Ts'o <tytso@....edu>
CC:     Andreas Dilger <adilger@...ger.ca>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Eric Biggers <ebiggers@...nel.org>,
        Ext4 Developers List <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH v2] chattr/lsattr: Support dax attribute

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@...fujitsu.com>  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@...fujitsu.com>   wrote:
>>>>> Use the letter 'x' to set/get dax attribute on a directory/file.
>>>>>
>>>>> Signed-off-by: Xiao Yang<yangx.jy@...fujitsu.com>
>>>> One minor nit below, but otherwise looks OK.
>>>>
>>>> Reviewed-by: Andreas Dilger<adilger@...ger.ca>
>>>>
>>>>> 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
>
>
>
>
>

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