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@xxxxxxxxxxxxxx>
> ---
>
> 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
>
>
>
