Re: [PATCH v1 0/5] io_uring: add xattr support

[Clay Harris <bugs@claycon.org>]

On Mon, Nov 29 2021 at 20:16:02 -0700, Andreas Dilger quoth thus:

> 
> > On Nov 29, 2021, at 6:08 PM, Clay Harris <bugs@claycon.org> wrote:
> > 
> > On Mon, Nov 29 2021 at 14:12:52 -0800, Stefan Roesch quoth thus:
> > 
> >> This adds the xattr support to io_uring. The intent is to have a more
> >> complete support for file operations in io_uring.
> >> 
> >> This change adds support for the following functions to io_uring:
> >> - fgetxattr
> >> - fsetxattr
> >> - getxattr
> >> - setxattr
> > 
> > You may wish to consider the following.
> > 
> > Patching for these functions makes for an excellent opportunity
> > to provide a better interface.  Rather than implement fXetattr
> > at all, you could enable io_uring to use functions like:
> > 
> > int Xetxattr(int dfd, const char *path, const char *name,
> > 	[const] void *value, size_t size, int flags);
> 
> This would naturally be named "...xattrat()"?

Indeed!

> > Not only does this simplify the io_uring interface down to two
> > functions, but modernizes and fixes a deficit in usability.
> > In terms of io_uring, this is just changing internal interfaces.
> 
> Even better would be the ability to get/set an array of xattrs in
> one call, to avoid repeated path lookups in the common case of
> handling multiple xattrs on a single file.

True.

> > Although unnecessary for io_uring, it would be nice to at least
> > consider what parts of this code could be leveraged for future
> > Xetxattr2 syscalls.
s/Xetxattr2/Xetxattrat/

> > 
> >> Patch 1: fs: make user_path_at_empty() take a struct filename
> >>  The user_path_at_empty filename parameter has been changed
> >>  from a const char user pointer to a filename struct. io_uring
> >>  operates on filenames.
> >>  In addition also the functions that call user_path_at_empty
> >>  in namei.c and stat.c have been modified for this change.
> >> 
> >> Patch 2: fs: split off setxattr_setup function from setxattr
> >>  Split off the setup part of the setxattr function
> >> 
> >> Patch 3: fs: split off the vfs_getxattr from getxattr
> >>  Split of the vfs_getxattr part from getxattr. This will
> >>  allow to invoke it from io_uring.
> >> 
> >> Patch 4: io_uring: add fsetxattr and setxattr support
> >>  This adds new functions to support the fsetxattr and setxattr
> >>  functions.
> >> 
> >> Patch 5: io_uring: add fgetxattr and getxattr support
> >>  This adds new functions to support the fgetxattr and getxattr
> >>  functions.
> >> 
> >> 
> >> There are two additional patches:
> >>  liburing: Add support for xattr api's.
> >>            This also includes the tests for the new code.
> >>  xfstests: Add support for io_uring xattr support.
> >> 
> >> 
> >> Stefan Roesch (5):
> >>  fs: make user_path_at_empty() take a struct filename
> >>  fs: split off setxattr_setup function from setxattr
> >>  fs: split off the vfs_getxattr from getxattr
> >>  io_uring: add fsetxattr and setxattr support
> >>  io_uring: add fgetxattr and getxattr support
> >> 
> >> fs/internal.h                 |  23 +++
> >> fs/io_uring.c                 | 325 ++++++++++++++++++++++++++++++++++
> >> fs/namei.c                    |   5 +-
> >> fs/stat.c                     |   7 +-
> >> fs/xattr.c                    | 114 +++++++-----
> >> include/linux/namei.h         |   4 +-
> >> include/uapi/linux/io_uring.h |   8 +-
> >> 7 files changed, 439 insertions(+), 47 deletions(-)
> >> 
> >> 
> >> Signed-off-by: Stefan Roesch <shr@fb.com>
> >> base-commit: c2626d30f312afc341158e07bf088f5a23b4eeeb
> >> --
> >> 2.30.2
> 
> 
> Cheers, Andreas
> 
> 
> 
> 
>