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authorAl Viro <viro@zeniv.linux.org.uk>2014-11-01 17:57:28 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2014-12-11 05:30:20 +0300
commite149ed2b805fefdccf7ccdfc19eca22fdd4514ac (patch)
tree8c9cd88deff8c7309ca2acb8d4cb475aaca47b14 /include/linux/proc_ns.h
parentf77c80142e1afe6d5c16975ca5d7d1fc324b16f9 (diff)
downloadlinux-e149ed2b805fefdccf7ccdfc19eca22fdd4514ac.tar.xz
take the targets of /proc/*/ns/* symlinks to separate fs
New pseudo-filesystem: nsfs. Targets of /proc/*/ns/* live there now. It's not mountable (not even registered, so it's not in /proc/filesystems, etc.). Files on it *are* bindable - we explicitly permit that in do_loopback(). This stuff lives in fs/nsfs.c now; proc_ns_fget() moved there as well. get_proc_ns() is a macro now (it's simply returning ->i_private; would have been an inline, if not for header ordering headache). proc_ns_inode() is an ex-parrot. The interface used in procfs is ns_get_path(path, task, ops) and ns_get_name(buf, size, task, ops). Dentries and inodes are never hashed; a non-counting reference to dentry is stashed in ns_common (removed by ->d_prune()) and reused by ns_get_path() if present. See ns_get_path()/ns_prune_dentry/nsfs_evict() for details of that mechanism. As the result, proc_ns_follow_link() has stopped poking in nd->path.mnt; it does nd_jump_link() on a consistent <vfsmount,dentry> pair it gets from ns_get_path(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/proc_ns.h')
-rw-r--r--include/linux/proc_ns.h31
1 files changed, 18 insertions, 13 deletions
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 2837ff41cfe3..42dfc615dbf8 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -4,9 +4,11 @@
#ifndef _LINUX_PROC_NS_H
#define _LINUX_PROC_NS_H
+#include <linux/ns_common.h>
+
struct pid_namespace;
struct nsproxy;
-struct ns_common;
+struct path;
struct proc_ns_operations {
const char *name;
@@ -38,35 +40,38 @@ enum {
extern int pid_ns_prepare_proc(struct pid_namespace *ns);
extern void pid_ns_release_proc(struct pid_namespace *ns);
-extern struct file *proc_ns_fget(int fd);
-extern struct ns_common *get_proc_ns(struct inode *);
extern int proc_alloc_inum(unsigned int *pino);
extern void proc_free_inum(unsigned int inum);
-extern bool proc_ns_inode(struct inode *inode);
#else /* CONFIG_PROC_FS */
static inline int pid_ns_prepare_proc(struct pid_namespace *ns) { return 0; }
static inline void pid_ns_release_proc(struct pid_namespace *ns) {}
-static inline struct file *proc_ns_fget(int fd)
-{
- return ERR_PTR(-EINVAL);
-}
-
-static inline struct ns_common *get_proc_ns(struct inode *inode) { return NULL; }
-
static inline int proc_alloc_inum(unsigned int *inum)
{
*inum = 1;
return 0;
}
static inline void proc_free_inum(unsigned int inum) {}
-static inline bool proc_ns_inode(struct inode *inode) { return false; }
#endif /* CONFIG_PROC_FS */
-#define ns_alloc_inum(ns) proc_alloc_inum(&(ns)->inum)
+static inline int ns_alloc_inum(struct ns_common *ns)
+{
+ atomic_long_set(&ns->stashed, 0);
+ return proc_alloc_inum(&ns->inum);
+}
+
#define ns_free_inum(ns) proc_free_inum((ns)->inum)
+extern struct file *proc_ns_fget(int fd);
+#define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
+extern void *ns_get_path(struct path *path, struct task_struct *task,
+ const struct proc_ns_operations *ns_ops);
+
+extern int ns_get_name(char *buf, size_t size, struct task_struct *task,
+ const struct proc_ns_operations *ns_ops);
+extern void nsfs_init(void);
+
#endif /* _LINUX_PROC_NS_H */