Commit Graph

6 Commits

Author SHA1 Message Date
JANAK DESAI 741a295130 [PATCH] unshare system call -v5: unshare namespace
If the namespace structure is being shared, allocate a new one and copy
information from the current, shared, structure.

Signed-off-by: Janak Desai <janak@us.ibm.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-07 16:12:34 -08:00
Ram Pai 390c684367 [PATCH] making namespace_sem global
This removes the per-namespace semaphore in favor of a global semaphore.
This can have an effect on namespace scalability.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 18:18:10 -08:00
Al Viro 5addc5dd88 [PATCH] make /proc/mounts pollable
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 18:18:10 -08:00
Miklos Szeredi 1ce88cf466 [PATCH] namespace.c: fix race in mark_mounts_for_expiry()
This patch fixes a race found by Ram in mark_mounts_for_expiry() in
fs/namespace.c.

The bug can only be triggered with simultaneous exiting of a process having
a private namespace, and expiry of a mount from within that namespace.
It's practically impossible to trigger, and I haven't even tried.  But
still, a bug is a bug.

The race happens when put_namespace() is called by another task, while
mark_mounts_for_expiry() is between atomic_read() and get_namespace().  In
that case get_namespace() will be called on an already dead namespace with
unforeseeable results.

The solution was suggested by Al Viro, with his own words:

      Instead of screwing with atomic_read() in there, why don't we
      simply do the following:
      	a) atomic_dec_and_lock() in put_namespace()
      	b) __put_namespace() called without dropping lock
      	c) the first thing done by __put_namespace would be
      struct vfsmount *root = namespace->root;
      namespace->root = NULL;
      spin_unlock(...);
      ....
      umount_tree(root);
      ...
      	d) check in mark_... would be simply namespace && namespace->root.

      And we are all set; no screwing around with atomic_read(), no magic
      at all.  Dying namespace gets NULL ->root.
      All changes of ->root happen under spinlock.
      If under a spinlock we see non-NULL ->mnt_namespace, it won't be
      freed until we drop the lock (we will set ->mnt_namespace to NULL
      under that lock before we get to freeing namespace).
      If under a spinlock we see non-NULL ->mnt_namespace and
      ->mnt_namespace->root, we can grab a reference to namespace and be
      sure that it won't go away.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:51 -07:00
Adrian Bunk 52c1da3953 [PATCH] make various thing static
Another rollup of patches which give various symbols static scope

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 00:06:43 -07:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00