@@ -1728,11 +1728,25 @@ void task_dump_owner(struct task_struct *task, mode_t mode,
*rgid = gid;
}
+void proc_pid_evict_inode(struct proc_inode *ei)
+{
+ struct pid *pid = ei->pid;
+
+ if (S_ISDIR(ei->vfs_inode.i_mode)) {
+ spin_lock(&pid->wait_pidfd.lock);
+ hlist_del_init_rcu(&ei->sibling_inodes);
+ spin_unlock(&pid->wait_pidfd.lock);
+ }
+
+ put_pid(pid);
+}
+
struct inode *proc_pid_make_inode(struct super_block * sb,
struct task_struct *task, umode_t mode)
{
struct inode * inode;
struct proc_inode *ei;
+ struct pid *pid;
/* We need a new inode */
@@ -1750,10 +1764,18 @@ struct inode *proc_pid_make_inode(struct super_block * sb,
/*
* grab the reference to task.
*/
- ei->pid = get_task_pid(task, PIDTYPE_PID);
- if (!ei->pid)
+ pid = get_task_pid(task, PIDTYPE_PID);
+ if (!pid)
goto out_unlock;
+ /* Let the pid remember us for quick removal */
+ ei->pid = pid;
+ if (S_ISDIR(mode)) {
+ spin_lock(&pid->wait_pidfd.lock);
+ hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
+ spin_unlock(&pid->wait_pidfd.lock);
+ }
+
task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
security_task_to_inode(task, inode);
@@ -3015,90 +3037,29 @@ static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *de
.permission = proc_pid_permission,
};
-static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
-{
- struct dentry *dentry, *leader, *dir;
- char buf[10 + 1];
- struct qstr name;
-
- name.name = buf;
- name.len = snprintf(buf, sizeof(buf), "%u", pid);
- /* no ->d_hash() rejects on procfs */
- dentry = d_hash_and_lookup(mnt->mnt_root, &name);
- if (dentry) {
- d_invalidate(dentry);
- dput(dentry);
- }
-
- if (pid == tgid)
- return;
-
- name.name = buf;
- name.len = snprintf(buf, sizeof(buf), "%u", tgid);
- leader = d_hash_and_lookup(mnt->mnt_root, &name);
- if (!leader)
- goto out;
-
- name.name = "task";
- name.len = strlen(name.name);
- dir = d_hash_and_lookup(leader, &name);
- if (!dir)
- goto out_put_leader;
-
- name.name = buf;
- name.len = snprintf(buf, sizeof(buf), "%u", pid);
- dentry = d_hash_and_lookup(dir, &name);
- if (dentry) {
- d_invalidate(dentry);
- dput(dentry);
- }
-
- dput(dir);
-out_put_leader:
- dput(leader);
-out:
- return;
-}
-
/**
- * proc_flush_task - Remove dcache entries for @task from the /proc dcache.
- * @task: task that should be flushed.
+ * proc_flush_pid - Remove dcache entries for @pid from the /proc dcache.
+ * @pid: pid that should be flushed.
*
- * When flushing dentries from proc, one needs to flush them from global
- * proc (proc_mnt) and from all the namespaces' procs this task was seen
- * in. This call is supposed to do all of this job.
- *
- * Looks in the dcache for
- * /proc/@pid
- * /proc/@tgid/task/@pid
- * if either directory is present flushes it and all of it'ts children
- * from the dcache.
+ * This function walks a list of inodes (that belong to any proc
+ * filesystem) that are attached to the pid and flushes them from
+ * the dentry cache.
*
* It is safe and reasonable to cache /proc entries for a task until
* that task exits. After that they just clog up the dcache with
* useless entries, possibly causing useful dcache entries to be
- * flushed instead. This routine is proved to flush those useless
- * dcache entries at process exit time.
+ * flushed instead. This routine is provided to flush those useless
+ * dcache entries when a process is reaped.
*
* NOTE: This routine is just an optimization so it does not guarantee
- * that no dcache entries will exist at process exit time it
- * just makes it very unlikely that any will persist.
+ * that no dcache entries will exist after a process is reaped
+ * it just makes it very unlikely that any will persist.
*/
-void proc_flush_task(struct task_struct *task)
+void proc_flush_pid(struct pid *pid)
{
- int i;
- struct pid *pid, *tgid;
- struct upid *upid;
-
- pid = task_pid(task);
- tgid = task_tgid(task);
-
- for (i = 0; i <= pid->level; i++) {
- upid = &pid->numbers[i];
- proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
- tgid->numbers[i].nr);
- }
+ proc_invalidate_siblings_dcache(&pid->inodes, &pid->wait_pidfd.lock);
+ put_pid(pid);
}
static int proc_pid_instantiate(struct inode *dir,
@@ -39,7 +39,7 @@ static void proc_evict_inode(struct inode *inode)
/* Stop tracking associated processes */
if (ei->pid) {
- put_pid(ei->pid);
+ proc_pid_evict_inode(ei);
ei->pid = NULL;
}
@@ -151,6 +151,7 @@ extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
extern const struct dentry_operations pid_dentry_operations;
extern int pid_getattr(struct vfsmount *, struct dentry *, struct kstat *);
extern int proc_setattr(struct dentry *, struct iattr *);
+extern void proc_pid_evict_inode(struct proc_inode *);
extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
extern int pid_revalidate(struct dentry *, unsigned int);
extern int pid_delete_dentry(const struct dentry *);
@@ -63,6 +63,7 @@ struct pid
unsigned int level;
/* lists of tasks that use this pid */
struct hlist_head tasks[PIDTYPE_MAX];
+ struct hlist_head inodes;
/* wait queue for pidfd notifications */
wait_queue_head_t wait_pidfd;
struct rcu_head rcu;
@@ -12,7 +12,7 @@
#ifdef CONFIG_PROC_FS
extern void proc_root_init(void);
-extern void proc_flush_task(struct task_struct *);
+extern void proc_flush_pid(struct pid *);
extern struct proc_dir_entry *proc_symlink(const char *,
struct proc_dir_entry *, const char *);
@@ -48,7 +48,7 @@ static inline void proc_root_init(void)
{
}
-static inline void proc_flush_task(struct task_struct *task)
+static inline void proc_flush_pid(struct pid *pid)
{
}
@@ -168,6 +168,7 @@ static void delayed_put_task_struct(struct rcu_head *rhp)
void release_task(struct task_struct *p)
{
struct task_struct *leader;
+ struct pid *thread_pid;
int zap_leader;
repeat:
/* don't need to get the RCU readlock here - the process is dead and
@@ -176,10 +177,9 @@ void release_task(struct task_struct *p)
atomic_dec(&__task_cred(p)->user->processes);
rcu_read_unlock();
- proc_flush_task(p);
-
write_lock_irq(&tasklist_lock);
ptrace_release_task(p);
+ thread_pid = get_pid(p->pids[PIDTYPE_PID].pid);
__exit_signal(p);
/*
@@ -202,6 +202,7 @@ void release_task(struct task_struct *p)
}
write_unlock_irq(&tasklist_lock);
+ proc_flush_pid(thread_pid);
release_thread(p);
call_rcu(&p->rcu, delayed_put_task_struct);
@@ -334,6 +334,7 @@ struct pid *alloc_pid(struct pid_namespace *ns)
INIT_HLIST_HEAD(&pid->tasks[type]);
init_waitqueue_head(&pid->wait_pidfd);
+ INIT_HLIST_HEAD(&pid->inodes);
upid = pid->numbers + ns->level;
spin_lock_irq(&pidmap_lock);