[PATCH v3 00/13] Fixes for major copy_file_range() issues

[Amir Goldstein <amir73il@gmail.com>]

Hi Darrick,

Following is a re-work of Dave Chinner's copy_file_range() patches.
This v3 patch set is based on your feedback to v2 [1].

NOTE that this work changes user visible behavior of copy_file_range(2)!
It introduces new errors for cases that were not checked before and it
allows cross-device copy by default. After this work, cifs copy offload
should be possible between two shares on the same server, but I did not
check this functionality.

Patches 1-3 have your Reviewed-by.
Patches 4-5 have been slightly amended to address your comments.
Patch 6 adds the new helper you requested dubbed file_modified().
Patch 7 uses the helper in xfs - unrelated to copy_file_range().
Patches 8-12 use the helper for various fs's ->copy_file_range().
Patch 13 (unmodified) has your Reviewed-by, because the bits that
you approved are those that matter to most filesystems (i.e. the
fallback logic).

The man page update patch (again, mostly Dave's work) is appended
to the series with fixes to your review comments.

Thanks,
Amir.

[1] https://lore.kernel.org/linux-fsdevel/20190526061100.21761-1-amir73il@gmail.com/

Changes since v2:
- Re-order generic_remap_checks() fix patch before
  forking generic_copy_file_checks()
- Document @req_count helper argument (Darrick)
- Fold generic_access_check_limits() (Darrick)
- Added file_modified() helper (Darrick)
- Added xfs patch to use file_modified() helper
- Drop generic_copy_file_range_prep() helper
- Per filesystem patch for file_modified()/file_accessed()
- Post copy file_remove_privs() for ceph/generic (Darrick)

Changes since v1:
- Short read instead of EINVAL (Christoph)
- generic_file_rw_checks() helper (Darrick)
- generic_copy_file_range_prep() helper (Christoph)
- Not calling ->remap_file_range() with different sb
- Not calling ->copy_file_range() with different fs type
- Remove changes to overlayfs
- Extra fix to clone/dedupe checks

Amir Goldstein (11):
  vfs: introduce generic_file_rw_checks()
  vfs: remove redundant checks from generic_remap_checks()
  vfs: add missing checks to copy_file_range
  vfs: introduce file_modified() helper
  xfs: use file_modified() helper
  vfs: copy_file_range needs to strip setuid bits and update timestamps
  ceph: copy_file_range needs to strip setuid bits and update timestamps
  cifs: copy_file_range needs to strip setuid bits and update timestamps
  fuse: copy_file_range needs to strip setuid bits and update timestamps
  nfs: copy_file_range needs to strip setuid bits and update timestamps
  vfs: allow copy_file_range to copy across devices

Dave Chinner (2):
  vfs: introduce generic_copy_file_range()
  vfs: no fallback for ->copy_file_range

 fs/ceph/file.c     |  40 ++++++++++++-
 fs/cifs/cifsfs.c   |  15 ++++-
 fs/fuse/file.c     |  29 ++++++++-
 fs/inode.c         |  20 +++++++
 fs/nfs/nfs42proc.c |   9 ++-
 fs/nfs/nfs4file.c  |  23 ++++++-
 fs/read_write.c    | 145 ++++++++++++++++++++++++++++-----------------
 fs/xfs/xfs_file.c  |  15 +----
 include/linux/fs.h |   9 +++
 mm/filemap.c       | 110 +++++++++++++++++++++++++++-------
 10 files changed, 309 insertions(+), 106 deletions(-)

-- 
2.17.1