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author | Eric W. Biederman <ebiederm@xmission.com> | 2011-06-15 10:21:48 -0700 |
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committer | Ziyan <jaraidaniel@gmail.com> | 2016-03-11 16:08:59 +0100 |
commit | e1405a6b24b7f9b84aee7aff6db09e5ca5c17cec (patch) | |
tree | 3480b8e0e625b0036af678e672a6491225e71ab6 /kernel/pid.c | |
parent | a6bf34a158d63bc888bb8c89b86cbc95e5d986c3 (diff) | |
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proc: Usable inode numbers for the namespace file descriptors.
Assign a unique proc inode to each namespace, and use that
inode number to ensure we only allocate at most one proc
inode for every namespace in proc.
A single proc inode per namespace allows userspace to test
to see if two processes are in the same namespace.
This has been a long requested feature and only blocked because
a naive implementation would put the id in a global space and
would ultimately require having a namespace for the names of
namespaces, making migration and certain virtualization tricks
impossible.
We still don't have per superblock inode numbers for proc, which
appears necessary for application unaware checkpoint/restart and
migrations (if the application is using namespace file descriptors)
but that is now allowd by the design if it becomes important.
I have preallocated the ipc and uts initial proc inode numbers so
their structures can be statically initialized.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
(cherry picked from commit 98f842e675f96ffac96e6c50315790912b2812be)
Diffstat (limited to 'kernel/pid.c')
-rw-r--r-- | kernel/pid.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/pid.c b/kernel/pid.c index 57a8346..29d34a1 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -78,6 +78,7 @@ struct pid_namespace init_pid_ns = { .last_pid = 0, .level = 0, .child_reaper = &init_task, + .proc_inum = PROC_PID_INIT_INO, }; EXPORT_SYMBOL_GPL(init_pid_ns); |