summaryrefslogtreecommitdiff
path: root/fs/autofs4/waitq.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/autofs4/waitq.c')
-rw-r--r--fs/autofs4/waitq.c559
1 files changed, 0 insertions, 559 deletions
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
deleted file mode 100644
index 8a566fa66afe..000000000000
--- a/fs/autofs4/waitq.c
+++ /dev/null
@@ -1,559 +0,0 @@
-/*
- * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
- * Copyright 2001-2006 Ian Kent <raven@themaw.net>
- *
- * This file is part of the Linux kernel and is made available under
- * the terms of the GNU General Public License, version 2, or at your
- * option, any later version, incorporated herein by reference.
- */
-
-#include <linux/slab.h>
-#include <linux/time.h>
-#include <linux/signal.h>
-#include <linux/sched/signal.h>
-#include <linux/file.h>
-#include "autofs_i.h"
-
-/* We make this a static variable rather than a part of the superblock; it
- * is better if we don't reassign numbers easily even across filesystems
- */
-static autofs_wqt_t autofs_next_wait_queue = 1;
-
-void autofs_catatonic_mode(struct autofs_sb_info *sbi)
-{
- struct autofs_wait_queue *wq, *nwq;
-
- mutex_lock(&sbi->wq_mutex);
- if (sbi->catatonic) {
- mutex_unlock(&sbi->wq_mutex);
- return;
- }
-
- pr_debug("entering catatonic mode\n");
-
- sbi->catatonic = 1;
- wq = sbi->queues;
- sbi->queues = NULL; /* Erase all wait queues */
- while (wq) {
- nwq = wq->next;
- wq->status = -ENOENT; /* Magic is gone - report failure */
- kfree(wq->name.name);
- wq->name.name = NULL;
- wq->wait_ctr--;
- wake_up_interruptible(&wq->queue);
- wq = nwq;
- }
- fput(sbi->pipe); /* Close the pipe */
- sbi->pipe = NULL;
- sbi->pipefd = -1;
- mutex_unlock(&sbi->wq_mutex);
-}
-
-static int autofs_write(struct autofs_sb_info *sbi,
- struct file *file, const void *addr, int bytes)
-{
- unsigned long sigpipe, flags;
- const char *data = (const char *)addr;
- ssize_t wr = 0;
-
- sigpipe = sigismember(&current->pending.signal, SIGPIPE);
-
- mutex_lock(&sbi->pipe_mutex);
- while (bytes) {
- wr = __kernel_write(file, data, bytes, &file->f_pos);
- if (wr <= 0)
- break;
- data += wr;
- bytes -= wr;
- }
- mutex_unlock(&sbi->pipe_mutex);
-
- /* Keep the currently executing process from receiving a
- * SIGPIPE unless it was already supposed to get one
- */
- if (wr == -EPIPE && !sigpipe) {
- spin_lock_irqsave(&current->sighand->siglock, flags);
- sigdelset(&current->pending.signal, SIGPIPE);
- recalc_sigpending();
- spin_unlock_irqrestore(&current->sighand->siglock, flags);
- }
-
- /* if 'wr' returned 0 (impossible) we assume -EIO (safe) */
- return bytes == 0 ? 0 : wr < 0 ? wr : -EIO;
-}
-
-static void autofs_notify_daemon(struct autofs_sb_info *sbi,
- struct autofs_wait_queue *wq,
- int type)
-{
- union {
- struct autofs_packet_hdr hdr;
- union autofs_packet_union v4_pkt;
- union autofs_v5_packet_union v5_pkt;
- } pkt;
- struct file *pipe = NULL;
- size_t pktsz;
- int ret;
-
- pr_debug("wait id = 0x%08lx, name = %.*s, type=%d\n",
- (unsigned long) wq->wait_queue_token,
- wq->name.len, wq->name.name, type);
-
- memset(&pkt, 0, sizeof(pkt)); /* For security reasons */
-
- pkt.hdr.proto_version = sbi->version;
- pkt.hdr.type = type;
-
- switch (type) {
- /* Kernel protocol v4 missing and expire packets */
- case autofs_ptype_missing:
- {
- struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
-
- pktsz = sizeof(*mp);
-
- mp->wait_queue_token = wq->wait_queue_token;
- mp->len = wq->name.len;
- memcpy(mp->name, wq->name.name, wq->name.len);
- mp->name[wq->name.len] = '\0';
- break;
- }
- case autofs_ptype_expire_multi:
- {
- struct autofs_packet_expire_multi *ep =
- &pkt.v4_pkt.expire_multi;
-
- pktsz = sizeof(*ep);
-
- ep->wait_queue_token = wq->wait_queue_token;
- ep->len = wq->name.len;
- memcpy(ep->name, wq->name.name, wq->name.len);
- ep->name[wq->name.len] = '\0';
- break;
- }
- /*
- * Kernel protocol v5 packet for handling indirect and direct
- * mount missing and expire requests
- */
- case autofs_ptype_missing_indirect:
- case autofs_ptype_expire_indirect:
- case autofs_ptype_missing_direct:
- case autofs_ptype_expire_direct:
- {
- struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
- struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
-
- pktsz = sizeof(*packet);
-
- packet->wait_queue_token = wq->wait_queue_token;
- packet->len = wq->name.len;
- memcpy(packet->name, wq->name.name, wq->name.len);
- packet->name[wq->name.len] = '\0';
- packet->dev = wq->dev;
- packet->ino = wq->ino;
- packet->uid = from_kuid_munged(user_ns, wq->uid);
- packet->gid = from_kgid_munged(user_ns, wq->gid);
- packet->pid = wq->pid;
- packet->tgid = wq->tgid;
- break;
- }
- default:
- pr_warn("bad type %d!\n", type);
- mutex_unlock(&sbi->wq_mutex);
- return;
- }
-
- pipe = get_file(sbi->pipe);
-
- mutex_unlock(&sbi->wq_mutex);
-
- switch (ret = autofs_write(sbi, pipe, &pkt, pktsz)) {
- case 0:
- break;
- case -ENOMEM:
- case -ERESTARTSYS:
- /* Just fail this one */
- autofs_wait_release(sbi, wq->wait_queue_token, ret);
- break;
- default:
- autofs_catatonic_mode(sbi);
- break;
- }
- fput(pipe);
-}
-
-static int autofs_getpath(struct autofs_sb_info *sbi,
- struct dentry *dentry, char **name)
-{
- struct dentry *root = sbi->sb->s_root;
- struct dentry *tmp;
- char *buf;
- char *p;
- int len;
- unsigned seq;
-
-rename_retry:
- buf = *name;
- len = 0;
-
- seq = read_seqbegin(&rename_lock);
- rcu_read_lock();
- spin_lock(&sbi->fs_lock);
- for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
- len += tmp->d_name.len + 1;
-
- if (!len || --len > NAME_MAX) {
- spin_unlock(&sbi->fs_lock);
- rcu_read_unlock();
- if (read_seqretry(&rename_lock, seq))
- goto rename_retry;
- return 0;
- }
-
- *(buf + len) = '\0';
- p = buf + len - dentry->d_name.len;
- strncpy(p, dentry->d_name.name, dentry->d_name.len);
-
- for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
- *(--p) = '/';
- p -= tmp->d_name.len;
- strncpy(p, tmp->d_name.name, tmp->d_name.len);
- }
- spin_unlock(&sbi->fs_lock);
- rcu_read_unlock();
- if (read_seqretry(&rename_lock, seq))
- goto rename_retry;
-
- return len;
-}
-
-static struct autofs_wait_queue *
-autofs_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr)
-{
- struct autofs_wait_queue *wq;
-
- for (wq = sbi->queues; wq; wq = wq->next) {
- if (wq->name.hash == qstr->hash &&
- wq->name.len == qstr->len &&
- wq->name.name &&
- !memcmp(wq->name.name, qstr->name, qstr->len))
- break;
- }
- return wq;
-}
-
-/*
- * Check if we have a valid request.
- * Returns
- * 1 if the request should continue.
- * In this case we can return an autofs_wait_queue entry if one is
- * found or NULL to idicate a new wait needs to be created.
- * 0 or a negative errno if the request shouldn't continue.
- */
-static int validate_request(struct autofs_wait_queue **wait,
- struct autofs_sb_info *sbi,
- const struct qstr *qstr,
- const struct path *path, enum autofs_notify notify)
-{
- struct dentry *dentry = path->dentry;
- struct autofs_wait_queue *wq;
- struct autofs_info *ino;
-
- if (sbi->catatonic)
- return -ENOENT;
-
- /* Wait in progress, continue; */
- wq = autofs_find_wait(sbi, qstr);
- if (wq) {
- *wait = wq;
- return 1;
- }
-
- *wait = NULL;
-
- /* If we don't yet have any info this is a new request */
- ino = autofs_dentry_ino(dentry);
- if (!ino)
- return 1;
-
- /*
- * If we've been asked to wait on an existing expire (NFY_NONE)
- * but there is no wait in the queue ...
- */
- if (notify == NFY_NONE) {
- /*
- * Either we've betean the pending expire to post it's
- * wait or it finished while we waited on the mutex.
- * So we need to wait till either, the wait appears
- * or the expire finishes.
- */
-
- while (ino->flags & AUTOFS_INF_EXPIRING) {
- mutex_unlock(&sbi->wq_mutex);
- schedule_timeout_interruptible(HZ/10);
- if (mutex_lock_interruptible(&sbi->wq_mutex))
- return -EINTR;
-
- if (sbi->catatonic)
- return -ENOENT;
-
- wq = autofs_find_wait(sbi, qstr);
- if (wq) {
- *wait = wq;
- return 1;
- }
- }
-
- /*
- * Not ideal but the status has already gone. Of the two
- * cases where we wait on NFY_NONE neither depend on the
- * return status of the wait.
- */
- return 0;
- }
-
- /*
- * If we've been asked to trigger a mount and the request
- * completed while we waited on the mutex ...
- */
- if (notify == NFY_MOUNT) {
- struct dentry *new = NULL;
- struct path this;
- int valid = 1;
-
- /*
- * If the dentry was successfully mounted while we slept
- * on the wait queue mutex we can return success. If it
- * isn't mounted (doesn't have submounts for the case of
- * a multi-mount with no mount at it's base) we can
- * continue on and create a new request.
- */
- if (!IS_ROOT(dentry)) {
- if (d_unhashed(dentry) &&
- d_really_is_positive(dentry)) {
- struct dentry *parent = dentry->d_parent;
-
- new = d_lookup(parent, &dentry->d_name);
- if (new)
- dentry = new;
- }
- }
- this.mnt = path->mnt;
- this.dentry = dentry;
- if (path_has_submounts(&this))
- valid = 0;
-
- if (new)
- dput(new);
- return valid;
- }
-
- return 1;
-}
-
-int autofs_wait(struct autofs_sb_info *sbi,
- const struct path *path, enum autofs_notify notify)
-{
- struct dentry *dentry = path->dentry;
- struct autofs_wait_queue *wq;
- struct qstr qstr;
- char *name;
- int status, ret, type;
- pid_t pid;
- pid_t tgid;
-
- /* In catatonic mode, we don't wait for nobody */
- if (sbi->catatonic)
- return -ENOENT;
-
- /*
- * Try translating pids to the namespace of the daemon.
- *
- * Zero means failure: we are in an unrelated pid namespace.
- */
- pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
- tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
- if (pid == 0 || tgid == 0)
- return -ENOENT;
-
- if (d_really_is_negative(dentry)) {
- /*
- * A wait for a negative dentry is invalid for certain
- * cases. A direct or offset mount "always" has its mount
- * point directory created and so the request dentry must
- * be positive or the map key doesn't exist. The situation
- * is very similar for indirect mounts except only dentrys
- * in the root of the autofs file system may be negative.
- */
- if (autofs_type_trigger(sbi->type))
- return -ENOENT;
- else if (!IS_ROOT(dentry->d_parent))
- return -ENOENT;
- }
-
- name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
- if (!name)
- return -ENOMEM;
-
- /* If this is a direct mount request create a dummy name */
- if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
- qstr.len = sprintf(name, "%p", dentry);
- else {
- qstr.len = autofs_getpath(sbi, dentry, &name);
- if (!qstr.len) {
- kfree(name);
- return -ENOENT;
- }
- }
- qstr.name = name;
- qstr.hash = full_name_hash(dentry, name, qstr.len);
-
- if (mutex_lock_interruptible(&sbi->wq_mutex)) {
- kfree(qstr.name);
- return -EINTR;
- }
-
- ret = validate_request(&wq, sbi, &qstr, path, notify);
- if (ret <= 0) {
- if (ret != -EINTR)
- mutex_unlock(&sbi->wq_mutex);
- kfree(qstr.name);
- return ret;
- }
-
- if (!wq) {
- /* Create a new wait queue */
- wq = kmalloc(sizeof(struct autofs_wait_queue), GFP_KERNEL);
- if (!wq) {
- kfree(qstr.name);
- mutex_unlock(&sbi->wq_mutex);
- return -ENOMEM;
- }
-
- wq->wait_queue_token = autofs_next_wait_queue;
- if (++autofs_next_wait_queue == 0)
- autofs_next_wait_queue = 1;
- wq->next = sbi->queues;
- sbi->queues = wq;
- init_waitqueue_head(&wq->queue);
- memcpy(&wq->name, &qstr, sizeof(struct qstr));
- wq->dev = autofs_get_dev(sbi);
- wq->ino = autofs_get_ino(sbi);
- wq->uid = current_uid();
- wq->gid = current_gid();
- wq->pid = pid;
- wq->tgid = tgid;
- wq->status = -EINTR; /* Status return if interrupted */
- wq->wait_ctr = 2;
-
- if (sbi->version < 5) {
- if (notify == NFY_MOUNT)
- type = autofs_ptype_missing;
- else
- type = autofs_ptype_expire_multi;
- } else {
- if (notify == NFY_MOUNT)
- type = autofs_type_trigger(sbi->type) ?
- autofs_ptype_missing_direct :
- autofs_ptype_missing_indirect;
- else
- type = autofs_type_trigger(sbi->type) ?
- autofs_ptype_expire_direct :
- autofs_ptype_expire_indirect;
- }
-
- pr_debug("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
- (unsigned long) wq->wait_queue_token, wq->name.len,
- wq->name.name, notify);
-
- /*
- * autofs_notify_daemon() may block; it will unlock ->wq_mutex
- */
- autofs_notify_daemon(sbi, wq, type);
- } else {
- wq->wait_ctr++;
- pr_debug("existing wait id = 0x%08lx, name = %.*s, nfy=%d\n",
- (unsigned long) wq->wait_queue_token, wq->name.len,
- wq->name.name, notify);
- mutex_unlock(&sbi->wq_mutex);
- kfree(qstr.name);
- }
-
- /*
- * wq->name.name is NULL iff the lock is already released
- * or the mount has been made catatonic.
- */
- wait_event_killable(wq->queue, wq->name.name == NULL);
- status = wq->status;
-
- /*
- * For direct and offset mounts we need to track the requester's
- * uid and gid in the dentry info struct. This is so it can be
- * supplied, on request, by the misc device ioctl interface.
- * This is needed during daemon resatart when reconnecting
- * to existing, active, autofs mounts. The uid and gid (and
- * related string values) may be used for macro substitution
- * in autofs mount maps.
- */
- if (!status) {
- struct autofs_info *ino;
- struct dentry *de = NULL;
-
- /* direct mount or browsable map */
- ino = autofs_dentry_ino(dentry);
- if (!ino) {
- /* If not lookup actual dentry used */
- de = d_lookup(dentry->d_parent, &dentry->d_name);
- if (de)
- ino = autofs_dentry_ino(de);
- }
-
- /* Set mount requester */
- if (ino) {
- spin_lock(&sbi->fs_lock);
- ino->uid = wq->uid;
- ino->gid = wq->gid;
- spin_unlock(&sbi->fs_lock);
- }
-
- if (de)
- dput(de);
- }
-
- /* Are we the last process to need status? */
- mutex_lock(&sbi->wq_mutex);
- if (!--wq->wait_ctr)
- kfree(wq);
- mutex_unlock(&sbi->wq_mutex);
-
- return status;
-}
-
-
-int autofs_wait_release(struct autofs_sb_info *sbi,
- autofs_wqt_t wait_queue_token, int status)
-{
- struct autofs_wait_queue *wq, **wql;
-
- mutex_lock(&sbi->wq_mutex);
- for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
- if (wq->wait_queue_token == wait_queue_token)
- break;
- }
-
- if (!wq) {
- mutex_unlock(&sbi->wq_mutex);
- return -EINVAL;
- }
-
- *wql = wq->next; /* Unlink from chain */
- kfree(wq->name.name);
- wq->name.name = NULL; /* Do not wait on this queue */
- wq->status = status;
- wake_up(&wq->queue);
- if (!--wq->wait_ctr)
- kfree(wq);
- mutex_unlock(&sbi->wq_mutex);
-
- return 0;
-}