[PATCH 0/8] overlayfs: fix ro/rw fd data inconsistecies

From: Miklos Szeredi
Date: Thu Dec 01 2016 - 05:16:54 EST


Hi Al,

I'd like to hear your opinion on this patchset before queuing up for 4.10.

Here's the problem:

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.

Git tree is here:

git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git #overlayfs-rorw

Pathset is against #overlayfs-next.

Thanks,
Miklos

---
Miklos Szeredi (8):
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
Revert "ovl: Warn on copy up if a process has a R/O fd open to the
lower file"

fs/internal.h | 1 -
fs/open.c | 2 +-
fs/overlayfs/copy_up.c | 34 -------
fs/overlayfs/inode.c | 227 +++++++++++++++++++++++++++++++++++++++++++++++
fs/overlayfs/overlayfs.h | 2 +
fs/overlayfs/super.c | 1 +
include/linux/fs.h | 1 +
mm/util.c | 22 +++++
8 files changed, 254 insertions(+), 36 deletions(-)

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2.5.5