[PATCH 0/7] overlayfs: fix ro/rw fd data inconsistecies

[Miklos Szeredi <mszeredi@redhat.com>]

A file is opened for read-only, opened read-write (resulting in a copy up)
and modified.  The data read back from the the read-only fd will be stale
in this case (the read-only file descriptor still refers to the lower,
unmodified file).

This patchset fixes issues related to this corner case.

The VFS impact is minimal and performance in the non-corner cases shouldn't
suffer.
---
Miklos Szeredi (7):
  vfs: allow overlayfs to intercept file ops
  vfs: export filp_clone_open()
  mm: ovl: copy-up on MAP_SHARED
  ovl: add infrastructure for intercepting file ops
  ovl: intercept read_iter
  ovl: intercept mmap
  ovl: intercept fsync

 fs/internal.h            |   1 -
 fs/open.c                |   2 +-
 fs/overlayfs/inode.c     | 225 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/overlayfs/overlayfs.h |   2 +
 fs/overlayfs/super.c     |   1 +
 include/linux/fs.h       |   1 +
 mm/util.c                |  22 +++++
 7 files changed, 252 insertions(+), 2 deletions(-)

-- 
2.5.5