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procfs: switch /proc/self away from proc_dir_entry

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Just have it pinned in dcache all along and let procfs ->kill_sb()
drop it before kill_anon_super().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2013-03-29 19:27:05 -04:00
parent 0ecc833bac
commit 021ada7dff
6 changed files with 56 additions and 12 deletions
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16
fs/proc/base.c
View File

@ -2794,7 +2794,7 @@ retry:
return iter;
}
#define TGID_OFFSET (FIRST_PROCESS_ENTRY)
#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 1)
static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct tgid_iter iter)
@ -2817,13 +2817,21 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
struct tgid_iter iter;
struct pid_namespace *ns;
filldir_t __filldir;
loff_t pos = filp->f_pos;
if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
goto out;
ns = filp->f_dentry->d_sb->s_fs_info;
if (pos == TGID_OFFSET - 1) {
if (proc_fill_cache(filp, dirent, filldir, "self", 4,
NULL, NULL, NULL) < 0)
goto out;
iter.tgid = 0;
} else {
iter.tgid = pos - TGID_OFFSET;
}
iter.task = NULL;
iter.tgid = filp->f_pos - TGID_OFFSET;
ns = filp->f_dentry->d_sb->s_fs_info;
for (iter = next_tgid(ns, iter);
iter.task;
iter.tgid += 1, iter = next_tgid(ns, iter)) {

2
fs/proc/inode.c
View File

@ -506,5 +506,5 @@ int proc_fill_super(struct super_block *s)
return -ENOMEM;
}
return 0;
return proc_setup_self(s);
}

1
fs/proc/internal.h
View File

@ -205,3 +205,4 @@ int proc_setattr(struct dentry *dentry, struct iattr *attr);
extern const struct inode_operations proc_ns_dir_inode_operations;
extern const struct file_operations proc_ns_dir_operations;
extern int proc_setup_self(struct super_block *);

2
fs/proc/root.c
View File

@ -137,6 +137,8 @@ static void proc_kill_sb(struct super_block *sb)
struct pid_namespace *ns;
ns = (struct pid_namespace *)sb->s_fs_info;
if (ns->proc_self)
dput(ns->proc_self);
kill_anon_super(sb);
put_pid_ns(ns);
}

46
fs/proc/self.c
View File

@ -1,6 +1,7 @@
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/namei.h>
#include <linux/pid_namespace.h>
#include "internal.h"
/*
* /proc/self:
@ -48,12 +49,43 @@ static const struct inode_operations proc_self_inode_operations = {
.put_link = proc_self_put_link,
};
static unsigned self_inum;
int proc_setup_self(struct super_block *s)
{
struct inode *root_inode = s->s_root->d_inode;
struct pid_namespace *ns = s->s_fs_info;
struct dentry *self;
mutex_lock(&root_inode->i_mutex);
self = d_alloc_name(s->s_root, "self");
if (self) {
struct inode *inode = new_inode_pseudo(s);
if (inode) {
inode->i_ino = self_inum;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_mode = S_IFLNK | S_IRWXUGO;
inode->i_uid = GLOBAL_ROOT_UID;
inode->i_gid = GLOBAL_ROOT_GID;
inode->i_op = &proc_self_inode_operations;
d_add(self, inode);
} else {
dput(self);
self = ERR_PTR(-ENOMEM);
}
} else {
self = ERR_PTR(-ENOMEM);
}
mutex_unlock(&root_inode->i_mutex);
if (IS_ERR(self)) {
pr_err("proc_fill_super: can't allocate /proc/self\n");
return PTR_ERR(self);
}
ns->proc_self = self;
return 0;
}
void __init proc_self_init(void)
{
struct proc_dir_entry *proc_self_symlink;
umode_t mode;
mode = S_IFLNK | S_IRWXUGO;
proc_self_symlink = proc_create("self", mode, NULL, NULL );
proc_self_symlink->proc_iops = &proc_self_inode_operations;
proc_alloc_inum(&self_inum);
}

1
include/linux/pid_namespace.h
View File

@ -28,6 +28,7 @@ struct pid_namespace {
struct pid_namespace *parent;
#ifdef CONFIG_PROC_FS
struct vfsmount *proc_mnt;
struct dentry *proc_self;
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
struct bsd_acct_struct *bacct;