[PATCH v2] chattr/lsattr: Support dax attribute

[PATCH v2] chattr/lsattr: Support dax attribute

[Xiao Yang]

Use the letter 'x' to set/get dax attribute on a directory/file.

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
---

V1->V2:
1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
2) Add more detailed description about 'x' attribute.
3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
   pagecache bypass) so remove the related info.

 lib/e2p/pf.c         |  1 +
 lib/ext2fs/ext2_fs.h |  1 +
 misc/chattr.1.in     | 15 ++++++++++++---
 misc/chattr.c        |  3 ++-
 4 files changed, 16 insertions(+), 4 deletions(-)

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" },
 	{ 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

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

[Xiao Yang]

Hi，

Is there any comment on the v2 patch?

Thanks,
Xiao Yang
On 2020/7/28 13:33, Xiao Yang wrote:
> Use the letter 'x' to set/get dax attribute on a directory/file.
>
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> ---
>
> V1->V2:
> 1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
> 2) Add more detailed description about 'x' attribute.
> 3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
>    pagecache bypass) so remove the related info.
>
>  lib/e2p/pf.c         |  1 +
>  lib/ext2fs/ext2_fs.h |  1 +
>  misc/chattr.1.in     | 15 ++++++++++++---
>  misc/chattr.c        |  3 ++-
>  4 files changed, 16 insertions(+), 4 deletions(-)
>
> 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" },
>  	{ 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 }
>  };

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

[Ira Weiny]

On Tue, Jul 28, 2020 at 01:33:21PM +0800, Xiao Yang wrote:
> Use the letter 'x' to set/get dax attribute on a directory/file.
> 
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> ---
> 
> V1->V2:
> 1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
> 2) Add more detailed description about 'x' attribute.
> 3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
>    pagecache bypass) so remove the related info.
> 
>  lib/e2p/pf.c         |  1 +
>  lib/ext2fs/ext2_fs.h |  1 +
>  misc/chattr.1.in     | 15 ++++++++++++---
>  misc/chattr.c        |  3 ++-
>  4 files changed, 16 insertions(+), 4 deletions(-)
> 
> 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" },
>  	{ 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 */

Per-file support is not supported on ext2...

So I'm suspicious of this change.  It is probably not an issue but I just
wanted to check if you are trying to test on ext2?

Ira

>  #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
> 
> 
> 

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

[Xiao Yang]

On 2020/8/8 0:03, Ira Weiny wrote:
> On Tue, Jul 28, 2020 at 01:33:21PM +0800, Xiao Yang wrote:
>> Use the letter 'x' to set/get dax attribute on a directory/file.
>>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
>> ---
>>
>> V1->V2:
>> 1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
>> 2) Add more detailed description about 'x' attribute.
>> 3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
>>     pagecache bypass) so remove the related info.
>>
>>   lib/e2p/pf.c         |  1 +
>>   lib/ext2fs/ext2_fs.h |  1 +
>>   misc/chattr.1.in     | 15 ++++++++++++---
>>   misc/chattr.c        |  3 ++-
>>   4 files changed, 16 insertions(+), 4 deletions(-)
>>
>> 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" },
>>   	{ 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 */
> Per-file support is not supported on ext2...
>
> So I'm suspicious of this change.  It is probably not an issue but I just
> wanted to check if you are trying to test on ext2?
Hi Ira,

Thanks for your reply. :-)
chattr failed to set the 'x' flag on ext2 sliently because ext2_ioctl() 
in kernel drops
unsupported 'FS_DAX_FL' sliently:
----------------------------------------------
# touch file
# chattr +x file;echo $?
0
# lsattr file
--------------------- file
----------------------------------------------

ext2_ioctl() drops all unsupported flags sliently(see the following 
code) so I am
not sure if we should return -EOPNOTSUPP for the unsupported  FS_DAX_FL:
----------------------------------------------
long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
...
         case EXT2_IOC_SETFLAGS: {
...
                 flags = flags & EXT2_FL_USER_MODIFIABLE;
                 flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
                 ei->i_flags = flags;

                 ext2_set_inode_flags(inode);
...
----------------------------------------------

Best Regards,
Xiao Yang
> Ira
>
>>   #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
>>
>>
>>
>
> .
>

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

[Andreas Dilger]

[-- Attachment #1: Type: text/plain, Size: 5212 bytes --]

On Aug 7, 2020, at 10:03 AM, Ira Weiny <ira.weiny@intel.com> wrote:
> 
> On Tue, Jul 28, 2020 at 01:33:21PM +0800, Xiao Yang wrote:
>> Use the letter 'x' to set/get dax attribute on a directory/file.
>> 
>> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
>> ---
>> 
>> V1->V2:
>> 1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
>> 2) Add more detailed description about 'x' attribute.
>> 3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
>>   pagecache bypass) so remove the related info.
>> 
>> lib/e2p/pf.c         |  1 +
>> lib/ext2fs/ext2_fs.h |  1 +
>> misc/chattr.1.in     | 15 ++++++++++++---
>> misc/chattr.c        |  3 ++-
>> 4 files changed, 16 insertions(+), 4 deletions(-)
>> 
>> 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" },
>> 	{ 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 */
> 
> Per-file support is not supported on ext2...
> 
> So I'm suspicious of this change.  It is probably not an issue but I just
> wanted to check if you are trying to test on ext2?

It is up to the kernel to handle the various flags, definitely the chattr
command should not be trying to guess which flags are supported, since
this can definitely change between kernels and the underlying filesystems.

Note that the headers in e2fsprogs are all using "ext2" in the name,
regardless of the fact that the flags apply to ext3 and ext4.

Cheers, Andreas

>> #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






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

[Andreas Dilger]

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On Jul 27, 2020, at 11:33 PM, Xiao Yang <yangx.jy@cn.fujitsu.com> wrote:
> 
> Use the letter 'x' to set/get dax attribute on a directory/file.
> 
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>

One minor nit below, but otherwise looks OK.

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

> 	{ 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






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

[Xiao Yang]

On 2020/8/13 7:25, Andreas Dilger wrote:
> On Aug 7, 2020, at 10:03 AM, Ira Weiny<ira.weiny@intel.com>  wrote:
>> On Tue, Jul 28, 2020 at 01:33:21PM +0800, Xiao Yang wrote:
>>> Use the letter 'x' to set/get dax attribute on a directory/file.
>>>
>>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
>>> ---
>>>
>>> V1->V2:
>>> 1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
>>> 2) Add more detailed description about 'x' attribute.
>>> 3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
>>>    pagecache bypass) so remove the related info.
>>>
>>> lib/e2p/pf.c         |  1 +
>>> lib/ext2fs/ext2_fs.h |  1 +
>>> misc/chattr.1.in     | 15 ++++++++++++---
>>> misc/chattr.c        |  3 ++-
>>> 4 files changed, 16 insertions(+), 4 deletions(-)
>>>
>>> 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" },
>>> 	{ 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 */
>> Per-file support is not supported on ext2...
>>
>> So I'm suspicious of this change.  It is probably not an issue but I just
>> wanted to check if you are trying to test on ext2?
> It is up to the kernel to handle the various flags, definitely the chattr
> command should not be trying to guess which flags are supported, since
> this can definitely change between kernels and the underlying filesystems.
Hi Andreas,

Agreed,  the various flags are handled by kernel instead of chattr 
command. :-)

Best Regards,
Xiao Yang
> Note that the headers in e2fsprogs are all using "ext2" in the name,
> regardless of the fact that the flags apply to ext3 and ext4.
>
> Cheers, Andreas
>
>>> #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
>
>
>
>
>

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

[Xiao Yang]

On 2020/8/13 7:29, Andreas Dilger wrote:
> On Jul 27, 2020, at 11:33 PM, Xiao Yang<yangx.jy@cn.fujitsu.com>  wrote:
>> Use the letter 'x' to set/get dax attribute on a directory/file.
>>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
> One minor nit below, but otherwise looks OK.
>
> Reviewed-by: Andreas Dilger<adilger@dilger.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
>
>
>
>
>

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

[Xiao Yang]

Hi,

Is there any comment on the patch? :-)

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

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

[Andreas Dilger]

[-- Attachment #1: Type: text/plain, Size: 5429 bytes --]

On Aug 27, 2020, at 7:33 PM, Xiao Yang <yangx.jy@cn.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@cn.fujitsu.com>  wrote:
>>>> Use the letter 'x' to set/get dax attribute on a directory/file.
>>>> 
>>>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
>>> One minor nit below, but otherwise looks OK.
>>> 
>>> Reviewed-by: Andreas Dilger<adilger@dilger.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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Re: [PATCH v2] chattr/lsattr: Support dax attribute

[Xiao Yang]

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

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

[Ira Weiny]

On Mon, Jul 27, 2020 at 10:33:21PM -0700, Xiao Yang wrote:
> Use the letter 'x' to set/get dax attribute on a directory/file.

This may allow the flag to be set but I don't think this implements the logic
within ext2 to properly support the flag does it?

Just a quick look shows that ext2_ioctl() does not have any dax checks in it
and you don't add them here?

So how does this work?  Does ext2 share all the code with ext4 to make it work?

Ira

> 
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> ---
> 
> V1->V2:
> 1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
> 2) Add more detailed description about 'x' attribute.
> 3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
>    pagecache bypass) so remove the related info.
> 
>  lib/e2p/pf.c         |  1 +
>  lib/ext2fs/ext2_fs.h |  1 +
>  misc/chattr.1.in     | 15 ++++++++++++---
>  misc/chattr.c        |  3 ++-
>  4 files changed, 16 insertions(+), 4 deletions(-)
> 
> 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" },
>  	{ 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
> 
> 
> 

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

[Xiao Yang]

On 2020/9/18 8:52, Ira Weiny wrote:
> On Mon, Jul 27, 2020 at 10:33:21PM -0700, Xiao Yang wrote:
>> Use the letter 'x' to set/get dax attribute on a directory/file.
> This may allow the flag to be set but I don't think this implements the logic
> within ext2 to properly support the flag does it?
Hi Ira,

In ext2, the dax flag cannot be set because ext2_ioctl() uses 
EXT2_FL_USER_MODIFIABLE to drop
the unsupported flag.
> Just a quick look shows that ext2_ioctl() does not have any dax checks in it
> and you don't add them here?
The dax flag never be passed into ext2 actually so I don't think we need 
some dax checks.
> So how does this work?  Does ext2 share all the code with ext4 to make it work?
1) ext2 without CONFIG_EXT4_USE_FOR_EXT2 unsupports the dax flag and 
ignores it sliently.
2) ext2 with CONFIG_EXT4_USE_FOR_EXT2 supports the dax flag.

Thanks,
Xiao Yang
> Ira
>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
>> ---
>>
>> V1->V2:
>> 1) Define FS_DAX_FL in order and add missing 'x' letter in manpage.
>> 2) Add more detailed description about 'x' attribute.
>> 3) 'x' is a separate attribute and doesn't always affect S_DAX(i.e.
>>     pagecache bypass) so remove the related info.
>>
>>   lib/e2p/pf.c         |  1 +
>>   lib/ext2fs/ext2_fs.h |  1 +
>>   misc/chattr.1.in     | 15 ++++++++++++---
>>   misc/chattr.c        |  3 ++-
>>   4 files changed, 16 insertions(+), 4 deletions(-)
>>
>> 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" },
>>   	{ 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
>>
>>
>>
>
> .
>

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

[Theodore Y. Ts'o]

On Tue, Jul 28, 2020 at 01:33:21PM +0800, Xiao Yang wrote:
> Use the letter 'x' to set/get dax attribute on a directory/file.
> 
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> Reviewed-by: Andreas Dilger <adilger@dilger.ca>

Thanks, applied.  Apologies for the delay.

		  	    	    - Ted

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

[Xiao Yang]

On 2020/10/2 4:56, Theodore Y. Ts'o wrote:
> On Tue, Jul 28, 2020 at 01:33:21PM +0800, Xiao Yang wrote:
>> Use the letter 'x' to set/get dax attribute on a directory/file.
>>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
>> Reviewed-by: Andreas Dilger<adilger@dilger.ca>
> Thanks, applied.  Apologies for the delay.
Hi Ted,

Thank you for applying this patch. :-)

Could you apply another fix for fsdax on ext4?
https://www.spinics.net/lists/linux-ext4/msg73863.html

Best Regards,
Xiao Yang
> 		  	    	- Ted
>
>
> .
>