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author | Miklos Szeredi <miklos@szeredi.hu> | 2005-08-07 09:42:25 -0700 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-08-07 10:00:38 -0700 |
commit | 68b47139ea94ab6d05e89c654db8daa99e9a232c (patch) | |
tree | 807d693b22a11f7667cd16e90b43618f85f8a4e0 /init | |
parent | 9ae5b3c703cce89a7d8ccf25fe16955ec6f016c0 (diff) |
[PATCH] namespace.c: fix bind mount from foreign namespace
I'm resending this patch, because I still believe it's the correct fix.
Tested before/after applying the patch with a test application
available from:
http://www.inf.bme.hu/~mszeredi/nstest.c
Bind mount from a foreign namespace results in an un-removable mount.
The reason is that mnt->mnt_namespace is copied from the old mount in
clone_mnt(). Because of this check_mnt() in sys_umount() will fail.
The solution is to set mnt->mnt_namespace to current->namespace in
clone_mnt(). clone_mnt() is either called from do_loopback() or
copy_tree(). copy_tree() is called from do_loopback() or
copy_namespace().
When called (directly or indirectly) from do_loopback(), always
current->namspace is being modified: check_mnt(nd->mnt). So setting
mnt->mnt_namespace to current->namspace is the right thing to do.
When called from copy_namespace(), the setting of mnt_namespace is
irrelevant, since mnt_namespace is reset later in that function for
all copied mounts.
Jamie said:
This patch is correct. The old code was buggy for more fundamental and
serious reason: it broke the invariant that a tree of vfsmnts all have the
same value of mnt_namespace (and the same for the mnt_list list).
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: Jamie Lokier <jamie@shareable.org>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'init')
0 files changed, 0 insertions, 0 deletions