[PATCH v2 00/16] Tidy up file permission hooks

[Amir Goldstein <amir73il@gmail.com>]

Hi Christian,

During my work on fanotify "pre content" events [1], Jan and I noticed
some inconsistencies in the call sites of security_file_permission()
hooks inside rw_verify_area() and remap_verify_area().

The majority of call sites are before file_start_write(), which is how
we want them to be for fanotify "pre content" events.

For splice code, there are many duplicate calls to rw_verify_area()
for the entire range as well as for partial ranges inside iterator.

This cleanup series, mostly following Jan's suggestions, moves all
the security_file_permission() hooks before file_start_write() and
eliminates duplicate permission hook calls in the same call chain.

The last 3 patches are helpers that I used in fanotify patches to
assert that permission hooks are called with expected locking scope.

Please stage this work on a stable branch in the vfs tree, so that
I will be able to send Jan fanotify patches for "pre content" events
based on the stable vfs branch.

Thanks,
Amir.

Changes since v1:
- Split coda locking reorder patch (jaharkes)
- Fix vfs_iocb_iter_write() file_end_write() bug (Josef)
- Fix subtle allow_file_dedupe() bug (+rename) (brauner)
- Fix some minor review nits (brauner)
- Added RVB from Josef and Chuck

[1] https://github.com/amir73il/linux/commits/fan_pre_content

Amir Goldstein (16):
  ovl: add permission hooks outside of do_splice_direct()
  splice: remove permission hook from do_splice_direct()
  splice: move permission hook out of splice_direct_to_actor()
  splice: move permission hook out of splice_file_to_pipe()
  splice: remove permission hook from iter_file_splice_write()
  remap_range: move permission hooks out of do_clone_file_range()
  remap_range: move file_start_write() to after permission hook
  btrfs: move file_start_write() to after permission hook
  coda: change locking order in coda_file_write_iter()
  fs: move file_start_write() into vfs_iter_write()
  fs: move permission hook out of do_iter_write()
  fs: move permission hook out of do_iter_read()
  fs: move kiocb_start_write() into vfs_iocb_iter_write()
  fs: create __sb_write_started() helper
  fs: create file_write_started() helper
  fs: create {sb,file}_write_not_started() helpers

 drivers/block/loop.c   |   2 -
 fs/btrfs/ioctl.c       |  12 +--
 fs/cachefiles/io.c     |   5 +-
 fs/coda/file.c         |   2 -
 fs/internal.h          |   8 +-
 fs/nfsd/vfs.c          |   7 +-
 fs/overlayfs/copy_up.c |  26 +++++-
 fs/overlayfs/file.c    |  10 +--
 fs/read_write.c        | 177 ++++++++++++++++++++++++++++-------------
 fs/remap_range.c       |  37 +++++----
 fs/splice.c            |  78 ++++++++++--------
 include/linux/fs.h     |  62 ++++++++++++++-
 12 files changed, 297 insertions(+), 129 deletions(-)

-- 
2.34.1