[PATCH v3 0/2] nfsd: sanely handle inabilty to fetch pre/post attributes

[Jeff Layton]

Boyang reported tripping the BUG_ON in set_change_info. While we
couldn't confirm it, one way this could happen would be for nfsd_lookup
to succeed and then for fh_fill_both_attrs to fail.

This patchset attempts to (sanely) fix this, usually by aborting the
operation if fetching the pre attributes fails. Post-op attribute fetch
handling is more difficult to deal with however since we've already done
the operation, so this has it just fudge the change_info4 if that
occurs.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
Changes in v2:
- rework the error paths to consistently use gotos
- add __must_check to fh_fill_pre_attrs and fh_fill_both_attrs
- fix bad error handling in setxattr codepath

---
Jeff Layton (2):
      nfsd: handle failure to collect pre/post-op attrs more sanely
      nfsd: remove unsafe BUG_ON from set_change_info

 fs/nfsd/nfs3proc.c |  4 +++-
 fs/nfsd/nfs4proc.c | 46 ++++++++++++++++++++++++++++++++++++++++------
 fs/nfsd/nfsfh.c    | 26 ++++++++++++++++----------
 fs/nfsd/nfsfh.h    |  6 +++---
 fs/nfsd/vfs.c      | 52 +++++++++++++++++++++++++++++++++++-----------------
 fs/nfsd/xdr4.h     | 11 -----------
 6 files changed, 97 insertions(+), 48 deletions(-)
---
base-commit: c9194156c1039499533303fc63a66b0f1399896b
change-id: 20230720-bz2223560-9c4690a8217b

Best regards,
-- 
Jeff Layton <jlayton@xxxxxxxxxx>