diff options
author | Al Viro <viro@zeniv.linux.org.uk> | 2014-11-01 10:57:28 -0400 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-12-10 21:30:20 -0500 |
commit | e149ed2b805fefdccf7ccdfc19eca22fdd4514ac (patch) | |
tree | 8c9cd88deff8c7309ca2acb8d4cb475aaca47b14 /include | |
parent | f77c80142e1afe6d5c16975ca5d7d1fc324b16f9 (diff) | |
download | linux-e149ed2b805fefdccf7ccdfc19eca22fdd4514ac.tar.bz2 |
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')
-rw-r--r-- | include/linux/ns_common.h | 1 | ||||
-rw-r--r-- | include/linux/proc_ns.h | 31 | ||||
-rw-r--r-- | include/uapi/linux/magic.h | 1 |
3 files changed, 20 insertions, 13 deletions
diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h index ce23cf4bbe69..85a5c8c16be9 100644 --- a/include/linux/ns_common.h +++ b/include/linux/ns_common.h @@ -4,6 +4,7 @@ struct proc_ns_operations; struct ns_common { + atomic_long_t stashed; const struct proc_ns_operations *ops; unsigned int inum; }; 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 */ diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index 77c60311a6c6..7d664ea85ebd 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -72,5 +72,6 @@ #define MTD_INODE_FS_MAGIC 0x11307854 #define ANON_INODE_FS_MAGIC 0x09041934 #define BTRFS_TEST_MAGIC 0x73727279 +#define NSFS_MAGIC 0x6e736673 #endif /* __LINUX_MAGIC_H__ */ |