diff options
Diffstat (limited to 'fs/autofs4/waitq.c')
| -rw-r--r-- | fs/autofs4/waitq.c | 559 |
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(¤t->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(¤t->sighand->siglock, flags); - sigdelset(¤t->pending.signal, SIGPIPE); - recalc_sigpending(); - spin_unlock_irqrestore(¤t->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; -} |