[PATCH v3 00/10] add support for name_to, open_by_handle_at() to io_uring

[Thomas Bertschinger <tahbertschinger@gmail.com>]

This series adds support for name_to_handle_at() and open_by_handle_at()
to io_uring. The idea is for these opcodes to be useful for userspace
NFS servers that want to use io_uring.

For both syscalls, io_uring will initially attempt to complete the
operation only using cached data, and will fall back to running in async
context when that is not possible.

Supporting this for open_by_handle_at() requires a way to communicate to
the filesystem that it should not block in its fh_to_dentry()
implementation. This is done with a new flag FILEID_CACHED which is set
in the file handle by the VFS. If a filesystem supports this new flag,
it will indicate that with a new flag EXPORT_OP_NONBLOCK so that the VFS
knows not to call into a filesystem with the FILEID_CACHED flag, when
the FS does not know about that flag.

Support for the new FILEID_CACHED flag is added for xfs.

v3 is mostly the same as [v2], with minor changes.

v2 -> v3:
- rename do_filp_path_open -> do_file_handle_open()
- rename the parameter fileid_type in xfs_fs_fh_to_{dentry,parent}() to
  fileid_type_flags
- a few minor style fixups reported by checkpatch.pl
- fix incorrect use of '&' instead of '&&' in exportfs_decode_fh_raw()
- add docs for EXPORT_OP_NONBLOCK in Documentation/filesystems/nfs/exporting.rst

[v2] https://lore.kernel.org/linux-fsdevel/20250910214927.480316-1-tahbertschinger@gmail.com/
[v1] https://lore.kernel.org/linux-fsdevel/20250814235431.995876-1-tahbertschinger@gmail.com/


Thomas Bertschinger (10):
  fhandle: create helper for name_to_handle_at(2)
  io_uring: add support for IORING_OP_NAME_TO_HANDLE_AT
  fhandle: helper for allocating, reading struct file_handle
  fhandle: create do_file_handle_open() helper
  fhandle: make do_file_handle_open() take struct open_flags
  exportfs: allow VFS flags in struct file_handle
  exportfs: new FILEID_CACHED flag for non-blocking fh lookup
  io_uring: add __io_open_prep() helper
  io_uring: add support for IORING_OP_OPEN_BY_HANDLE_AT
  xfs: add support for non-blocking fh_to_dentry()

 Documentation/filesystems/nfs/exporting.rst |   6 +
 fs/exportfs/expfs.c                         |  14 +-
 fs/fhandle.c                                | 155 +++++++++-------
 fs/internal.h                               |  13 ++
 fs/xfs/xfs_export.c                         |  34 +++-
 fs/xfs/xfs_export.h                         |   3 +-
 fs/xfs/xfs_handle.c                         |   2 +-
 include/linux/exportfs.h                    |  34 +++-
 include/uapi/linux/io_uring.h               |   3 +
 io_uring/opdef.c                            |  26 +++
 io_uring/openclose.c                        | 191 +++++++++++++++++++-
 io_uring/openclose.h                        |  13 ++
 12 files changed, 409 insertions(+), 85 deletions(-)


base-commit: 76eeb9b8de9880ca38696b2fb56ac45ac0a25c6c
-- 
2.51.0