[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: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a85b073..29539c2 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1532,6 +1532,7 @@
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_task_inode_operations = {
.lookup = proc_task_lookup,
+ .getattr = proc_task_getattr,
};
#ifdef CONFIG_SECURITY
@@ -1658,7 +1660,7 @@
*/
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 @@
}
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 @@
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;
+}
