Re: [PATCH 0/7] More NFS file handle unit tests

[Jeff Layton <jlayton@kernel.org>]

On Thu, 2017-11-02 at 12:15 +0200, Amir Goldstein wrote:
> Eryu,
> 
> This series enhances test coverage for generic NFS file handles
> encode/decode functionality and adds a new gereric/exportfs test.
> 
> Please note that the new test output includes the temporary test
> number 500, so don't forget to fix those when renaming the test.
> 
> The enhanced open_by_handle program is going to be used later on for
> overlayfs specific exportfs tests [1].
> 
> The open_by_handle program is limited to encoding "non-connectable"
> file handles (used by nfsd on 'no_subtree_check' exports), because there
> is no user available API (that I know of) to encode a "connecctable" file
> handle (used by nfsd on 'subtree_check' exports). I used a test patch
> "test connectable file handles", available on my tree [1] to tun the tests
> with "connectable" file handles.
> 
> I verified that the new test passes on xfs, ext4, ext2, btrfs, f2fs.
> However, the test fails on tmpfs due to:
> "open_by_handle() returned 116 incorrectly on an unlinked open file!"
> 
> This happens because tmpfs uses d_find_alias() to get a decoded dentry,
> but d_find_alias() skips unhashed (deleted with refcount) dentries.
> 
> I don't know if being able to decode a file handle of a deleted but open
> file is a requirement for nfsd or just a recommendation, but IMO it is a
> common case that is worth testing, even if tmpfs (or other file systems)
> choose not to fix this.
> 
> Bruce, Jeff,
> 
> What is your view on this issue?
> 
> 

It seems like something that should be a requirement.

A client could (for instance) send a READ for a filehandle with one of
the special anonymous stateids. If you can't decode the filehandle, you
really have no way to know what inode against which to issue the read.

> Thanks,
> Amir.
> 
> [1] https://github.com/amir73il/xfstests/commits/ovl-nfs-export
> [2] https://github.com/amir73il/linux/commits/ovl-nfs-export-v1
> 
> Amir Goldstein (7):
>   open_by_handle: add filename to error reports
>   open_by_handle: test file handles of renamed files
>   open_by_handle: test content of open file handle
>   open_by_handle: test directory file handle
>   open_by_handle: test file handles of open files
>   generic/426: factor out helper functions
>   fstests: add test with more open by file handle use cases
> 
>  src/open_by_handle.c  | 247 ++++++++++++++++++++++++++++++++++++++++++++------
>  tests/generic/426     |  40 +++++---
>  tests/generic/426.out |   4 +
>  tests/generic/500     | 119 ++++++++++++++++++++++++
>  tests/generic/500.out |  10 ++
>  tests/generic/group   |   1 +
>  6 files changed, 383 insertions(+), 38 deletions(-)
>  create mode 100755 tests/generic/500
>  create mode 100644 tests/generic/500.out
> 

-- 
Jeff Layton <jlayton@kernel.org>