[PATCH 0/3] io path options + reflink (mild security implications)

[Kent Overstreet <kent.overstreet@linux.dev>]

so, I've been fleshing out various things at the intersection of io path
options + rebalance + reflink, and this is the last little bit

background: bcachefs has io path options that can be set filesystem
wide, or per inode, and when changed rebalance automatically picks them
up and does the right thing

reflink adds a wrinkle, which is that we'd like e.g. recursively setting
the foreground/background targets on some files to move them to the
appropriate device (or nr_replicas etc.), like other data - but if a
user did a reflink copy of some other user's data and then set
nr_replicas=1, that would be bad.

so this series adds a flag to reflink pointers for "may propagate option
changes", which can then be set at remap_file_range() time based on
vfs level permission checks.

so, question for everyone: is write access to the source file what we
want? or should it be stricter, i.e. ownership matches?

then, we're currently missing mnt_idmap plumbing to remap_file_range()
to do said permissions checks - do we want to do that? or is there an
easier way?

Kent Overstreet (3):
  bcachefs: BCH_SB_VERSION_INCOMPAT
  bcachefs: bcachefs_metadata_version_reflink_p_may_update_opts
  bcachefs: Option changes now get propagated to reflinked data

 fs/bcachefs/bcachefs.h        |  2 ++
 fs/bcachefs/bcachefs_format.h | 28 +++++++++++--------
 fs/bcachefs/fs-io.c           |  9 ++++++-
 fs/bcachefs/move.c            | 51 ++++++++++++++++++++++++++++++-----
 fs/bcachefs/recovery.c        | 27 ++++++++++++++++---
 fs/bcachefs/reflink.c         | 18 ++++++++++---
 fs/bcachefs/reflink.h         |  3 ++-
 fs/bcachefs/reflink_format.h  |  2 ++
 fs/bcachefs/super-io.c        | 48 ++++++++++++++++++++++++++++++---
 fs/bcachefs/super-io.h        | 18 ++++++++++---
 10 files changed, 172 insertions(+), 34 deletions(-)

-- 
2.45.2