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Commit 6e66b52b authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
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[PATCH] proc: Fix the link count for /proc/<pid>/task 



Use getattr to get an accurate link count when needed.  This is cheaper and
more accurate than trying to derive it by walking the thread list of a
process.

Especially as it happens when needed stat instead of at readdir time.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0f2fe20f

fs/proc/base.c

+19 −2
Original line number Diff line number Diff line
@@ -1532,6 +1532,7 @@ out: 


static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);

static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);

static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat);



static struct file_operations proc_fd_operations = {

	.read		= generic_read_dir,
@@ -1552,6 +1553,7 @@ static struct inode_operations proc_fd_inode_operations = { 


static struct inode_operations proc_task_inode_operations = {

	.lookup		= proc_task_lookup,

	.getattr	= proc_task_getattr,

};



#ifdef CONFIG_SECURITY
@@ -1658,7 +1660,7 @@ static struct dentry *proc_pident_lookup(struct inode *dir, 
	 */

	switch(p->type) {

		case PROC_TGID_TASK:

			inode->i_nlink = 2 + get_tid_list(2, NULL, dir);

			inode->i_nlink = 2;

			inode->i_op = &proc_task_inode_operations;

			inode->i_fop = &proc_task_operations;

			break;
@@ -2261,7 +2263,6 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi 
	}



	nr_tids = get_tid_list(pos, tid_array, inode);

	inode->i_nlink = pos + nr_tids;



	for (i = 0; i < nr_tids; i++) {

		unsigned long j = PROC_NUMBUF;
@@ -2281,3 +2282,19 @@ out: 
	filp->f_pos = pos;

	return retval;

}



static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)

{

	struct inode *inode = dentry->d_inode;

	struct task_struct *p = proc_task(inode);

	generic_fillattr(inode, stat);



	if (pid_alive(p)) {

		task_lock(p);

		if (p->signal)

			stat->nlink += atomic_read(&p->signal->count);

		task_unlock(p);

	}



	return 0;

}