linux-kernel - [patch 0/5] union-directory implementation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 21 May 2009 11:22:31 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	jblunck@...e.de, bharata@...ibm.com, vaurora@...hat.com,
	viro@...iv.linux.org.uk
Subject: [patch 0/5] union-directory implementation

This patchset implements the simplest form of union mounts (called
union directories here).  This is somewhat similar to Plan9 union
mounts.  The patches are derived from Jan Blunck's work.

Also available from git:
  git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git union-dir

Features:

 - top level directory unification only
 - no copy up
 - no whiteouts, opaque dir, etc...
 - create/rename/unlink only work on top layer
 - write works on any layer (without copy up)
 - directory entry deduplication in kernel
 - supports directory seeking (that hell from POSIX)

Shortcomings:

 - directory reading is O(n^2), needs optimization
 - weird create/unlink semantics due to ignoring union

I'm posting these patches in a hope that

 a) they may be useful on their own (after further development),
 b) they may help with the full fledged union-mount implementation

Comments?

Thanks,
Miklos
--

Jan Blunck (5):
      union-directory: Introduce MNT_UNION and MS_UNION flags
      union-directory: Support for traversing the layers of a union-directory
      union-directory: Some checks during namespace changes
      union-directory: Make lookup continue in overlayed directories
      union-directory: Simple union-mount readdir implementation

---
 fs/Kconfig            |    8 ++
 fs/Makefile           |    2 +
 fs/file_table.c       |    1 +
 fs/namei.c            |   49 +++++++++++
 fs/namespace.c        |   25 +++++-
 fs/readdir.c          |   21 +++--
 fs/union.c            |  229 +++++++++++++++++++++++++++++++++++++++++++++++++
 fs/union.h            |   26 ++++++
 include/linux/fs.h    |   18 ++++
 include/linux/mount.h |    1 +
 10 files changed, 369 insertions(+), 11 deletions(-)
 create mode 100644 fs/union.c
 create mode 100644 fs/union.h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/