Commit 021ada7d authored by Al Viro's avatar Al Viro
Browse files

procfs: switch /proc/self away from proc_dir_entry 



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

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 0ecc833b

fs/proc/base.c

+12 −4
Original line number Diff line number Diff line
@@ -2794,7 +2794,7 @@ static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter ite 
	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)) {

fs/proc/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -506,5 +506,5 @@ int proc_fill_super(struct super_block *s) 
		return -ENOMEM;

	}



	return 0;

	return proc_setup_self(s);

}

fs/proc/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -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 *);

fs/proc/root.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

}

fs/proc/self.c

+39 −7
Original line number Diff line number Diff line 
#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,

};



void __init proc_self_init(void)

static unsigned self_inum;



int proc_setup_self(struct super_block *s)

{

	struct proc_dir_entry *proc_self_symlink;

	umode_t mode;

	struct inode *root_inode = s->s_root->d_inode;

	struct pid_namespace *ns = s->s_fs_info;

	struct dentry *self;

	

	mode = S_IFLNK | S_IRWXUGO;

	proc_self_symlink = proc_create("self", mode, NULL, NULL );

	proc_self_symlink->proc_iops = &proc_self_inode_operations;

	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)

{

	proc_alloc_inum(&self_inum);

}