Dave Hansen [EMAIL PROTECTED] wrote:
|
| The following patch completes the removal of proc_mnt. It fetches
| the mnt on which to do dentry invalidations from the pid_namespace
| in which the task appears.
|
| For now, there is only one pid namespace in mainline so this is
| straightforward. In the -lxc tree we'll have to do something
| more complex.
|
| Note that the new proc_compare_super() enforces the "one proc sb
| per pid_namespace" limit.
|
| ---
|
| lxc-dave/fs/proc/base.c | 26 ++++++++++++++++++++++--
| lxc-dave/fs/proc/inode.c | 2 -
| lxc-dave/fs/proc/root.c | 35
++++++++++++++++++++++++++-------
| lxc-dave/include/linux/pid_namespace.h | 1
| lxc-dave/include/linux/proc_fs.h | 1
| 5 files changed, 53 insertions(+), 12 deletions(-)
|
| diff -puN fs/proc/base.c~A3-remove-proc_mnt-1 fs/proc/base.c
| --- lxc/fs/proc/base.c~A3-remove-proc_mnt-1 2007-01-26 14:29:18.000000000
-0800
| +++ lxc-dave/fs/proc/base.c 2007-01-26 14:29:18.000000000 -0800
| @@ -70,6 +70,7 @@
| #include <linux/seccomp.h>
| #include <linux/cpuset.h>
| #include <linux/audit.h>
| +#include <linux/pid_namespace.h>
| #include <linux/poll.h>
| #include <linux/nsproxy.h>
| #include <linux/oom.h>
| @@ -1905,9 +1906,11 @@ static struct inode_operations proc_tgid
| };
|
| /**
| - * proc_flush_task - Remove dcache entries for @task from the /proc dcache.
| + * proc_flush_task_from_pid_ns - Remove dcache entries for @task
| + * from the /proc dcache.
| *
| * @task: task that should be flushed.
| + * @pid_ns: pid_namespace in which that task appears
| *
| * Looks in the dcache for
| * /proc/@pid
| @@ -1925,11 +1928,20 @@ static struct inode_operations proc_tgid
| * that no dcache entries will exist at process exit time it
| * just makes it very unlikely that any will persist.
| */
| -void proc_flush_task(struct task_struct *task)
| +void proc_flush_task_from_pid_ns(struct task_struct *task,
| + struct pid_namespace* pid_ns)
| {
| struct dentry *dentry, *leader, *dir;
| char buf[PROC_NUMBUF];
| struct qstr name;
| + struct vfsmount *proc_mnt = pid_ns->proc_mnt;
| +
| + /*
| + * It is possible that no /procs have been instantiated
| + * for this particular pid namespace.
| + */
| + if (!proc_mnt)
| + return;
|
| name.name = buf;
| name.len = snprintf(buf, sizeof(buf), "%d", task->pid);
| @@ -1971,6 +1983,16 @@ out:
| return;
| }
|
| +void proc_flush_task(struct task_struct *task)
| +{
| + /*
| + * Right now, tasks only appear in their own pid_ns.
| + * With containers this function will change to a loop
| + * over all pid_ns's in which the task appears.
| + */
| + proc_flush_task_from_pid_ns(task, current->nsproxy->pid_ns);
| +}
| +
| static struct dentry *proc_pid_instantiate(struct inode *dir,
| struct dentry * dentry,
| struct task_struct *task, void *ptr)
| diff -puN fs/proc/inode.c~A3-remove-proc_mnt-1 fs/proc/inode.c
| --- lxc/fs/proc/inode.c~A3-remove-proc_mnt-1 2007-01-26 14:29:18.000000000
-0800
| +++ lxc-dave/fs/proc/inode.c 2007-01-26 14:29:18.000000000 -0800
| @@ -67,8 +67,6 @@ static void proc_delete_inode(struct ino
| clear_inode(inode);
| }
|
| -struct vfsmount *proc_mnt;
| -
| static void proc_read_inode(struct inode * inode)
| {
| inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
| diff -puN fs/proc/root.c~A3-remove-proc_mnt-1 fs/proc/root.c
| --- lxc/fs/proc/root.c~A3-remove-proc_mnt-1 2007-01-26 14:29:18.000000000
-0800
| +++ lxc-dave/fs/proc/root.c 2007-01-26 14:29:18.000000000 -0800
| @@ -18,6 +18,7 @@
| #include <linux/bitops.h>
| #include <linux/smp_lock.h>
| #include <linux/mount.h>
| +#include <linux/pid_namespace.h>
|
| #include "internal.h"
|
| @@ -27,10 +28,36 @@ struct proc_dir_entry *proc_net, *proc_n
| struct proc_dir_entry *proc_sys_root;
| #endif
|
| +static int proc_compare_super(struct super_block *s, void *p)
| +{
| + struct pid_namespace *pid_ns = p;
| + if (pid_ns->proc_mnt->mnt_sb == s)
| + return 1;
| + return 0;
| +}
| +
| static int proc_get_sb(struct file_system_type *fs_type,
| int flags, const char *dev_name, void *data, struct vfsmount *mnt)
| {
| - return get_sb_single(fs_type, flags, data, proc_fill_super, mnt);
| + struct super_block *s;
| +
| + struct pid_namespace *pid_ns = current->nsproxy->pid_ns;
| + int error;
| +
| + s = sget(fs_type, proc_compare_super, set_anon_super, pid_ns);
| + if (IS_ERR(s))
| + return PTR_ERR(s);
| + if (!pid_ns->proc_mnt)
| + pid_ns->proc_mnt = mnt;
| +
| + error = fill_if_new_sb(s, pid_ns, flags, proc_fill_super);
| + if (error)
| + return error;
| +
| + do_remount_sb(s, flags, data, 0);
| + error = simple_set_mnt(mnt, s);
| +
| + return error;
| }
|
| static struct file_system_type proc_fs_type = {
| @@ -47,12 +74,6 @@ void __init proc_root_init(void)
| err = register_filesystem(&proc_fs_type);
| if (err)
| return;
| - proc_mnt = kern_mount(&proc_fs_type);
| - err = PTR_ERR(proc_mnt);
| - if (IS_ERR(proc_mnt)) {
| - unregister_filesystem(&proc_fs_type);
| - return;
| - }
If we remove the kern_mount() call here, where do we mount
/proc for the init_pid_ns now ? i.e how does proc_get_sb()
get called the first time ?
| proc_misc_init();
| proc_net = proc_mkdir("net", NULL);
| proc_net_stat = proc_mkdir("net/stat", NULL);
| diff -puN include/linux/pid_namespace.h~A3-remove-proc_mnt-1
include/linux/pid_namespace.h
| --- lxc/include/linux/pid_namespace.h~A3-remove-proc_mnt-1 2007-01-26
14:29:18.000000000 -0800
| +++ lxc-dave/include/linux/pid_namespace.h 2007-01-26 14:29:18.000000000
-0800
| @@ -20,6 +20,7 @@ struct pid_namespace {
| struct pidmap pidmap[PIDMAP_ENTRIES];
| int last_pid;
| struct task_struct *child_reaper;
| + struct vfsmount *proc_mnt;
| };
|
| extern struct pid_namespace init_pid_ns;
| diff -puN include/linux/proc_fs.h~A3-remove-proc_mnt-1 include/linux/proc_fs.h
| --- lxc/include/linux/proc_fs.h~A3-remove-proc_mnt-1 2007-01-26
14:29:18.000000000 -0800
| +++ lxc-dave/include/linux/proc_fs.h 2007-01-26 14:29:18.000000000 -0800
| @@ -109,7 +109,6 @@ extern struct proc_dir_entry *create_pro
| struct proc_dir_entry *parent);
| extern void remove_proc_entry(const char *name, struct proc_dir_entry
*parent);
|
| -extern struct vfsmount *proc_mnt;
| extern int proc_fill_super(struct super_block *,void *,int);
| extern struct inode *proc_get_inode(struct super_block *, unsigned int,
struct proc_dir_entry *);
|
| _
| _______________________________________________
| Containers mailing list
| [EMAIL PROTECTED]
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