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[PATCH 00/24] Read-only bind mounts

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To: <akpm@...>
Cc: <linux-kernel@...>, <hch@...>, Dave Hansen <haveblue@...>
Date: Monday, September 17, 2007 - 2:27 pm

If we can't pull the entire series into -mm, can we just put the
first three patches for now?  They can stand on their own.

---

Why do we need r/o bind mounts?

This feature allows a read-only view into a read-write filesystem.
In the process of doing that, it also provides infrastructure for
keeping track of the number of writers to any given mount.

This has a number of uses.  It allows chroots to have parts of
filesystems writable.  It will be useful for containers in the future
because users may have root inside a container, but should not
be allowed to write to somefilesystems.  This also replaces 
patches that vserver has had out of the tree for several years.

It allows security enhancement by making sure that parts of
your filesystem read-only (such as when you don't trust your
FTP server), when you don't want to have entire new filesystems
mounted, or when you want atime selectively updated.
I've been using the following script to test that the feature is
working as desired.  It takes a directory and makes a regular
bind and a r/o bind mount of it.  It then performs some normal
filesystem operations on the three directories, including ones
that are expected to fail, like creating a file on the r/o
mount.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
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Messages in current thread:
[PATCH 00/24] Read-only bind mounts, Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 00/24] Read-only bind mounts, Christoph Hellwig, (Wed Sep 19, 1:44 pm)
Re: [PATCH 00/24] Read-only bind mounts, Andrew Morton, (Wed Sep 19, 5:24 pm)
Re: [PATCH 00/24] Read-only bind mounts, Dave Hansen, (Wed Sep 19, 5:56 pm)
Re: [PATCH 00/24] Read-only bind mounts, Andrew Morton, (Wed Sep 19, 6:06 pm)
Re: [PATCH 00/24] Read-only bind mounts, Miklos Szeredi, (Thu Sep 20, 5:58 am)
Re: [PATCH 00/24] Read-only bind mounts, Serge E. Hallyn, (Wed Sep 19, 10:21 am)
Re: [PATCH 14/24] unix_find_other() elevate write count for ..., Christoph Hellwig, (Wed Sep 19, 1:35 pm)
[PATCH 22/24] do_rmdir(): elevate write count, Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 22/24] do_rmdir(): elevate write count, Christoph Hellwig, (Wed Sep 19, 1:39 pm)
Re: [PATCH 21/24] elevate mnt writers for vfs_unlink() callers, Christoph Hellwig, (Wed Sep 19, 1:38 pm)
Re: [PATCH 19/24] elevate write count for do_sys_utime() and..., Christoph Hellwig, (Wed Sep 19, 1:36 pm)
Re: [PATCH 20/24] sys_mknodat(): elevate write count for vfs..., Christoph Hellwig, (Wed Sep 19, 1:38 pm)
Re: [PATCH 09/24] elevate mnt writers for callers of vfs_mkd..., Christoph Hellwig, (Wed Sep 19, 1:32 pm)
[PATCH 04/24] r/o bind mounts: stub functions, Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 04/24] r/o bind mounts: stub functions, Christoph Hellwig, (Wed Sep 19, 1:28 pm)
Re: [PATCH 11/24] elevate write count for link and symlink c..., Christoph Hellwig, (Wed Sep 19, 1:33 pm)
Re: [PATCH 06/24] r/o bind mounts: elevate write count for s..., Christoph Hellwig, (Wed Sep 19, 1:31 pm)
[PATCH 18/24] elevate write count for do_utimes(), Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 18/24] elevate write count for do_utimes(), Christoph Hellwig, (Wed Sep 19, 1:36 pm)
Re: [PATCH 16/24] nfs: check mnt instead of superblock direc..., Christoph Hellwig, (Wed Sep 19, 1:36 pm)
Re: [PATCH 17/24] elevate writer count for do_sys_truncate(), Christoph Hellwig, (Wed Sep 19, 1:36 pm)
Re: [PATCH 15/24] elevate write count over calls to vfs_rena..., Christoph Hellwig, (Wed Sep 19, 1:35 pm)
Re: [PATCH 12/24] elevate mount count for extended attributes, Christoph Hellwig, (Wed Sep 19, 1:34 pm)
Re: [PATCH 10/24] elevate write count during entire ncp_ioct..., Christoph Hellwig, (Wed Sep 19, 1:33 pm)
Re: [PATCH 01/24] filesystem helpers for custom 'struct file's, Christoph Hellwig, (Wed Sep 19, 1:26 pm)
Re: [PATCH] docuement filesystem helpers for custom 'struct ..., Christoph Hellwig, (Thu Sep 20, 1:30 pm)
[PATCH 05/24] elevate write count open()'d files, Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 05/24] elevate write count open()'d files, Christoph Hellwig, (Wed Sep 19, 1:30 pm)
Re: [PATCH 07/24] elevate writer count for chown and friends, Christoph Hellwig, (Wed Sep 19, 1:31 pm)
Re: [PATCH 13/24] elevate write count for file_update_time(), Christoph Hellwig, (Wed Sep 19, 1:35 pm)
[PATCH 08/24] make access() use mnt check, Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 08/24] make access() use mnt check, Christoph Hellwig, (Wed Sep 19, 1:32 pm)
[PATCH 03/24] create cleanup helper svc_msnfs(), Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Jan Engelhardt, (Wed Sep 19, 1:39 pm)
Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Dave Hansen, (Wed Sep 19, 1:45 pm)
Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Trond Myklebust, (Wed Sep 19, 1:54 pm)
Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Christoph Hellwig, (Wed Sep 19, 1:59 pm)
Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Trond Myklebust, (Wed Sep 19, 2:10 pm)
Re: [PATCH 03/24] create cleanup helper svc_msnfs(), Christoph Hellwig, (Wed Sep 19, 1:28 pm)
[PATCH 02/24] rearrange may_open() to be r/o friendly, Dave Hansen, (Mon Sep 17, 2:27 pm)
Re: [PATCH 02/24] rearrange may_open() to be r/o friendly, Christoph Hellwig, (Wed Sep 19, 1:27 pm)
speck-geostationary