diff options
| -rw-r--r-- | fs/proc/base.c | 111 | ||||
| -rw-r--r-- | fs/proc/inode.c | 2 | ||||
| -rw-r--r-- | fs/proc/internal.h | 1 | ||||
| -rw-r--r-- | include/linux/pid.h | 1 | ||||
| -rw-r--r-- | include/linux/proc_fs.h | 4 | ||||
| -rw-r--r-- | kernel/exit.c | 4 | ||||
| -rw-r--r-- | kernel/pid.c | 1 |
7 files changed, 45 insertions, 79 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index c7c64272b0fa..e7efe9d6f3d6 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1834,11 +1834,25 @@ void task_dump_owner(struct task_struct *task, umode_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 */ @@ -1856,10 +1870,18 @@ 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); @@ -3230,90 +3252,29 @@ static const struct inode_operations proc_tgid_base_inode_operations = { .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 struct dentry *proc_pid_instantiate(struct dentry * dentry, diff --git a/fs/proc/inode.c b/fs/proc/inode.c index d9243b24554a..1e730ea1dcd6 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -40,7 +40,7 @@ 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; } diff --git a/fs/proc/internal.h b/fs/proc/internal.h index fd470172675f..9e294f0290e5 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -158,6 +158,7 @@ extern int proc_pid_statm(struct seq_file *, struct pid_namespace *, extern const struct dentry_operations pid_dentry_operations; extern int pid_getattr(const struct path *, struct kstat *, u32, unsigned int); 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 void pid_update_inode(struct task_struct *, struct inode *); extern int pid_delete_dentry(const struct dentry *); diff --git a/include/linux/pid.h b/include/linux/pid.h index 998ae7d24450..01a0d4e28506 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -62,6 +62,7 @@ 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; diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 3dfa92633af3..40a7982b7285 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -32,7 +32,7 @@ struct proc_ops { typedef int (*proc_write_t)(struct file *, char *, size_t); 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 *); @@ -105,7 +105,7 @@ 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) { } diff --git a/kernel/exit.c b/kernel/exit.c index 2833ffb0c211..502b4995b688 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -191,6 +191,7 @@ void put_task_struct_rcu_user(struct task_struct *task) 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 @@ -199,11 +200,11 @@ repeat: atomic_dec(&__task_cred(p)->user->processes); rcu_read_unlock(); - proc_flush_task(p); cgroup_release(p); write_lock_irq(&tasklist_lock); ptrace_release_task(p); + thread_pid = get_pid(p->thread_pid); __exit_signal(p); /* @@ -226,6 +227,7 @@ repeat: } write_unlock_irq(&tasklist_lock); + proc_flush_pid(thread_pid); release_thread(p); put_task_struct_rcu_user(p); diff --git a/kernel/pid.c b/kernel/pid.c index 0f4ecb57214c..ca08d6a3aa77 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -258,6 +258,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid, 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); |