Messages in this thread Patch in this message | | | Date | Fri, 06 Jul 2007 12:05:42 +0400 | From | Pavel Emelianov <> | Subject | [PATCH 5/16] Make proc be mountable from different pid namespaces |
| |
Each pid namespace should have the proc_mnt pointer even when there's no user mounts to make proc_flush_task() work. To do this we call the kern_mount() to obtain the proc mount point.
Since the current pid_namespace during this call is not the newly created one we use the introduced MS_KERNMOUNT flag to pass the namespace pointer to the proc_get_sb() call.
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
---
fs/proc/inode.c | 20 +++++-- fs/proc/internal.h | 2 fs/proc/root.c | 116 ++++++++++++++++++++++++++++++++++++++++-- include/linux/pid_namespace.h | 3 + include/linux/proc_fs.h | 15 +++++ 5 files changed, 147 insertions(+), 9 deletions(-)
diff -upr linux-2.6.22-rc4-mm2.orig/fs/proc/inode.c linux-2.6.22-rc4-mm2-2/fs/proc/inode.c --- linux-2.6.22-rc4-mm2.orig/fs/proc/inode.c 2007-06-14 12:14:29.000000000 +0400 +++ linux-2.6.22-rc4-mm2-2/fs/proc/inode.c 2007-07-04 19:00:38.000000000 +0400 @@ -16,6 +16,7 @@ #include <linux/init.h> #include <linux/module.h> #include <linux/smp_lock.h> +#include <linux/pid_namespace.h> #include <asm/system.h> #include <asm/uaccess.h> @@ -429,9 +430,17 @@ out_mod: return NULL; } -int proc_fill_super(struct super_block *s, void *data, int silent) +int proc_fill_super(struct super_block *s, struct pid_namespace *ns) { struct inode * root_inode; + struct proc_dir_entry * root_dentry; + + root_dentry = &proc_root; + if (ns != &init_pid_ns) { + root_dentry = create_proc_root(); + if (root_dentry == NULL) + goto out_no_de; + } s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; s->s_blocksize = 1024; @@ -440,8 +449,8 @@ int proc_fill_super(struct super_block * s->s_op = &proc_sops; s->s_time_gran = 1; - de_get(&proc_root); - root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); + de_get(root_dentry); + root_inode = proc_get_inode(s, PROC_ROOT_INO, root_dentry); if (!root_inode) goto out_no_root; root_inode->i_uid = 0; @@ -452,9 +461,10 @@ int proc_fill_super(struct super_block * return 0; out_no_root: - printk("proc_read_super: get root inode failed\n"); iput(root_inode); - de_put(&proc_root); + de_put(root_dentry); +out_no_de: + printk("proc_read_super: get root inode failed\n"); return -ENOMEM; } MODULE_LICENSE("GPL"); diff -upr linux-2.6.22-rc4-mm2.orig/fs/proc/internal.h linux-2.6.22-rc4-mm2-2/fs/proc/internal.h --- linux-2.6.22-rc4-mm2.orig/fs/proc/internal.h 2007-06-14 12:14:29.000000000 +0400 +++ linux-2.6.22-rc4-mm2-2/fs/proc/internal.h 2007-07-04 19:00:38.000000000 +0400 @@ -71,3 +71,5 @@ static inline int proc_fd(struct inode * { return PROC_I(inode)->fd; } + +struct proc_dir_entry * create_proc_root(void); diff -upr linux-2.6.22-rc4-mm2.orig/fs/proc/root.c linux-2.6.22-rc4-mm2-2/fs/proc/root.c --- linux-2.6.22-rc4-mm2.orig/fs/proc/root.c 2007-06-14 12:14:29.000000000 +0400 +++ linux-2.6.22-rc4-mm2-2/fs/proc/root.c 2007-07-04 19:00:39.000000000 +0400 @@ -18,32 +18,89 @@ #include <linux/bitops.h> #include <linux/smp_lock.h> #include <linux/mount.h> +#include <linux/pid_namespace.h> #include "internal.h" struct proc_dir_entry *proc_net, *proc_net_stat, *proc_bus, *proc_root_fs, *proc_root_driver; +static int proc_test_super(struct super_block *sb, void *data) +{ + return sb->s_fs_info == data; +} + +static int proc_set_super(struct super_block *sb, void *data) +{ + struct pid_namespace *ns; + + ns = (struct pid_namespace *)data; + sb->s_fs_info = get_pid_ns(ns); + return set_anon_super(sb, NULL); +} + static int proc_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { + int err; + struct super_block *sb; + struct pid_namespace *ns; + struct proc_inode *ei; + if (proc_mnt) { /* Seed the root directory with a pid so it doesn't need * to be special in base.c. I would do this earlier but * the only task alive when /proc is mounted the first time * is the init_task and it doesn't have any pids. */ - struct proc_inode *ei; ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode); if (!ei->pid) ei->pid = find_get_pid(1); } - return get_sb_single(fs_type, flags, data, proc_fill_super, mnt); + + if (flags & MS_KERNMOUNT) + ns = (struct pid_namespace *)data; + else + ns = current->nsproxy->pid_ns; + + sb = sget(fs_type, proc_test_super, proc_set_super, ns); + if (IS_ERR(sb)) + return PTR_ERR(sb); + + if (!sb->s_root) { + sb->s_flags = flags; + err = proc_fill_super(sb, ns); + if (err) { + up_write(&sb->s_umount); + deactivate_super(sb); + return err; + } + + ei = PROC_I(sb->s_root->d_inode); + if (!ei->pid) + ei->pid = find_get_pid(1); + sb->s_flags |= MS_ACTIVE; + + mntput(ns->proc_mnt); + ns->proc_mnt = mnt; + } + + return simple_set_mnt(mnt, sb); +} + +static void proc_kill_sb(struct super_block *sb) +{ + struct pid_namespace *ns; + + ns = (struct pid_namespace *)sb->s_fs_info; + kill_anon_super(sb); + if (ns != NULL) + put_pid_ns(ns); } static struct file_system_type proc_fs_type = { .name = "proc", .get_sb = proc_get_sb, - .kill_sb = kill_anon_super, + .kill_sb = proc_kill_sb, }; void __init proc_root_init(void) @@ -60,6 +117,7 @@ void __init proc_root_init(void) unregister_filesystem(&proc_fs_type); return; } + proc_misc_init(); proc_net = proc_mkdir("net", NULL); proc_net_stat = proc_mkdir("net/stat", NULL); @@ -153,6 +211,58 @@ struct proc_dir_entry proc_root = { .parent = &proc_root, }; +/* + * creates the proc root entry for different proc trees + */ + +struct proc_dir_entry * create_proc_root(void) +{ + struct proc_dir_entry *de; + + de = kzalloc(sizeof(struct proc_dir_entry), GFP_KERNEL); + if (de != NULL) { + de->low_ino = PROC_ROOT_INO; + de->namelen = 5; + de->name = "/proc"; + de->mode = S_IFDIR | S_IRUGO | S_IXUGO; + de->nlink = 2; + de->proc_iops = &proc_root_inode_operations; + de->proc_fops = &proc_root_operations; + de->parent = de; + } + return de; +} + +int pid_ns_prepare_proc(struct pid_namespace *ns) +{ + struct vfsmount *mnt; + + mnt = kern_mount_data(&proc_fs_type, ns); + if (!IS_ERR(mnt)) + /* + * do not save the reference from the proc super + * block to the namespace. otherwise we will get + * a circular reference ns->proc_mnt->mnt_sb->ns + */ + put_pid_ns(ns); + return 0; +} + +void pid_ns_release_proc(struct pid_namespace *ns) +{ + struct vfsmount *mnt; + + mnt = ns->proc_mnt; + /* + * do not put the namespace reference as it wa not get in + * pid_ns_prepare_proc(). safe to set NULL here as this + * namespace is already dead and all the proc mounts are + * released so nobudo will se this super block + */ + mnt->mnt_sb->s_fs_info = NULL; + mntput(mnt); +} + EXPORT_SYMBOL(proc_symlink); EXPORT_SYMBOL(proc_mkdir); EXPORT_SYMBOL(create_proc_entry); diff -upr linux-2.6.22-rc4-mm2.orig/include/linux/pid_namespace.h linux-2.6.22-rc4-mm2-2/include/linux/pid_namespace.h --- linux-2.6.22-rc4-mm2.orig/include/linux/pid_namespace.h 2007-06-14 12:14:29.000000000 +0400 +++ linux-2.6.22-rc4-mm2-2/include/linux/pid_namespace.h 2007-07-04 19:00:39.000000000 +0400 @@ -16,6 +15,9 @@ struct pidmap { struct task_struct *child_reaper; struct kmem_cache *pid_cachep; struct pid_namespace *parent; +#ifdef CONFIG_PROC_FS + struct vfsmount *proc_mnt; +#endif }; extern struct pid_namespace init_pid_ns; diff -upr linux-2.6.22-rc4-mm2.orig/include/linux/proc_fs.h linux-2.6.22-rc4-mm2-2/include/linux/proc_fs.h --- linux-2.6.22-rc4-mm2.orig/include/linux/proc_fs.h 2007-06-14 12:14:29.000000000 +0400 +++ linux-2.6.22-rc4-mm2-2/include/linux/proc_fs.h 2007-07-04 19:00:38.000000000 +0400 @@ -126,7 +126,8 @@ extern struct proc_dir_entry *create_pro 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); +struct pid_namespace; +extern int proc_fill_super(struct super_block *, struct pid_namespace *); extern struct inode *proc_get_inode(struct super_block *, unsigned int, struct proc_dir_entry *); /* @@ -143,6 +144,9 @@ extern const struct file_operations proc extern const struct file_operations proc_kmsg_operations; extern const struct file_operations ppc_htab_operations; +extern int pid_ns_prepare_proc(struct pid_namespace *ns); +extern void pid_ns_release_proc(struct pid_namespace *ns); + /* * proc_tty.c */ @@ -248,6 +254,15 @@ static inline void proc_tty_unregister_d extern struct proc_dir_entry proc_root; +static inline int pid_ns_prepare_proc(struct pid_namespace *ns) +{ + return 0; +} + +static inline void pid_ns_release_proc(struct pid_namespace *ns) +{ +} + #endif /* CONFIG_PROC_FS */ #if !defined(CONFIG_PROC_KCORE) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |