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![Linus Torvalds](/assets/img/avatar_default.png)
The previous comit made the autofs4 debug printouts check types against the printout format, and uncovered this bug: fs/autofs4/waitq.c:106:2: warning: format ‘%08lx’ expects type ‘long unsigned int’, but argument 4 has type ‘autofs_wqt_t’ which is due to the insane type for wait_queue_token. That thing should be some fixed well-defined size (preferably just 'unsigned int' or 'u32') but for unexplained reasons it is randomly either 'unsigned long' or 'unsigned int' depending on the architecture. For now, cast it to 'unsigned long' for printing, the way we do elsewhere. Somebody else can try to explain the typedef mess. (There's a reason we don't support excessive use of typedefs in the kernel: it's usually just a good way of confusing yourself). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
552 lines
14 KiB
C
552 lines
14 KiB
C
/* -*- c -*- --------------------------------------------------------------- *
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*
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* linux/fs/autofs/waitq.c
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*
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* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
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* Copyright 2001-2006 Ian Kent <raven@themaw.net>
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*
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* This file is part of the Linux kernel and is made available under
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* the terms of the GNU General Public License, version 2, or at your
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* option, any later version, incorporated herein by reference.
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*
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* ------------------------------------------------------------------------- */
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#include <linux/slab.h>
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#include <linux/time.h>
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#include <linux/signal.h>
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#include <linux/file.h>
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#include "autofs_i.h"
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/* We make this a static variable rather than a part of the superblock; it
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is better if we don't reassign numbers easily even across filesystems */
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static autofs_wqt_t autofs4_next_wait_queue = 1;
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/* These are the signals we allow interrupting a pending mount */
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#define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
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void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
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{
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struct autofs_wait_queue *wq, *nwq;
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mutex_lock(&sbi->wq_mutex);
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if (sbi->catatonic) {
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mutex_unlock(&sbi->wq_mutex);
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return;
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}
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DPRINTK("entering catatonic mode");
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sbi->catatonic = 1;
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wq = sbi->queues;
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sbi->queues = NULL; /* Erase all wait queues */
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while (wq) {
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nwq = wq->next;
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wq->status = -ENOENT; /* Magic is gone - report failure */
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if (wq->name.name) {
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kfree(wq->name.name);
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wq->name.name = NULL;
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}
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wq->wait_ctr--;
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wake_up_interruptible(&wq->queue);
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wq = nwq;
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}
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fput(sbi->pipe); /* Close the pipe */
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sbi->pipe = NULL;
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sbi->pipefd = -1;
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mutex_unlock(&sbi->wq_mutex);
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}
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static int autofs4_write(struct file *file, const void *addr, int bytes)
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{
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unsigned long sigpipe, flags;
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mm_segment_t fs;
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const char *data = (const char *)addr;
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ssize_t wr = 0;
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/** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/
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sigpipe = sigismember(¤t->pending.signal, SIGPIPE);
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/* Save pointer to user space and point back to kernel space */
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fs = get_fs();
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set_fs(KERNEL_DS);
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while (bytes &&
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(wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) {
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data += wr;
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bytes -= wr;
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}
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set_fs(fs);
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/* Keep the currently executing process from receiving a
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SIGPIPE unless it was already supposed to get one */
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if (wr == -EPIPE && !sigpipe) {
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spin_lock_irqsave(¤t->sighand->siglock, flags);
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sigdelset(¤t->pending.signal, SIGPIPE);
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recalc_sigpending();
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spin_unlock_irqrestore(¤t->sighand->siglock, flags);
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}
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return (bytes > 0);
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}
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static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
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struct autofs_wait_queue *wq,
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int type)
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{
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union {
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struct autofs_packet_hdr hdr;
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union autofs_packet_union v4_pkt;
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union autofs_v5_packet_union v5_pkt;
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} pkt;
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struct file *pipe = NULL;
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size_t pktsz;
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DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
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(unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type);
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memset(&pkt,0,sizeof pkt); /* For security reasons */
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pkt.hdr.proto_version = sbi->version;
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pkt.hdr.type = type;
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switch (type) {
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/* Kernel protocol v4 missing and expire packets */
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case autofs_ptype_missing:
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{
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struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
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pktsz = sizeof(*mp);
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mp->wait_queue_token = wq->wait_queue_token;
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mp->len = wq->name.len;
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memcpy(mp->name, wq->name.name, wq->name.len);
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mp->name[wq->name.len] = '\0';
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break;
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}
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case autofs_ptype_expire_multi:
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{
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struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;
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pktsz = sizeof(*ep);
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ep->wait_queue_token = wq->wait_queue_token;
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ep->len = wq->name.len;
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memcpy(ep->name, wq->name.name, wq->name.len);
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ep->name[wq->name.len] = '\0';
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break;
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}
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/*
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* Kernel protocol v5 packet for handling indirect and direct
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* mount missing and expire requests
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*/
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case autofs_ptype_missing_indirect:
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case autofs_ptype_expire_indirect:
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case autofs_ptype_missing_direct:
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case autofs_ptype_expire_direct:
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{
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struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
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pktsz = sizeof(*packet);
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packet->wait_queue_token = wq->wait_queue_token;
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packet->len = wq->name.len;
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memcpy(packet->name, wq->name.name, wq->name.len);
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packet->name[wq->name.len] = '\0';
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packet->dev = wq->dev;
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packet->ino = wq->ino;
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packet->uid = wq->uid;
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packet->gid = wq->gid;
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packet->pid = wq->pid;
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packet->tgid = wq->tgid;
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break;
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}
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default:
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printk("autofs4_notify_daemon: bad type %d!\n", type);
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return;
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}
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/* Check if we have become catatonic */
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mutex_lock(&sbi->wq_mutex);
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if (!sbi->catatonic) {
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pipe = sbi->pipe;
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get_file(pipe);
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}
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mutex_unlock(&sbi->wq_mutex);
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if (pipe) {
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if (autofs4_write(pipe, &pkt, pktsz))
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autofs4_catatonic_mode(sbi);
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fput(pipe);
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}
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}
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static int autofs4_getpath(struct autofs_sb_info *sbi,
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struct dentry *dentry, char **name)
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{
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struct dentry *root = sbi->sb->s_root;
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struct dentry *tmp;
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char *buf;
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char *p;
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int len;
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unsigned seq;
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rename_retry:
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buf = *name;
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len = 0;
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seq = read_seqbegin(&rename_lock);
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rcu_read_lock();
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spin_lock(&sbi->fs_lock);
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for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
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len += tmp->d_name.len + 1;
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if (!len || --len > NAME_MAX) {
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spin_unlock(&sbi->fs_lock);
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rcu_read_unlock();
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if (read_seqretry(&rename_lock, seq))
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goto rename_retry;
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return 0;
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}
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*(buf + len) = '\0';
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p = buf + len - dentry->d_name.len;
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strncpy(p, dentry->d_name.name, dentry->d_name.len);
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for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
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*(--p) = '/';
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p -= tmp->d_name.len;
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strncpy(p, tmp->d_name.name, tmp->d_name.len);
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}
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spin_unlock(&sbi->fs_lock);
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rcu_read_unlock();
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if (read_seqretry(&rename_lock, seq))
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goto rename_retry;
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return len;
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}
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static struct autofs_wait_queue *
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autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
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{
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struct autofs_wait_queue *wq;
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for (wq = sbi->queues; wq; wq = wq->next) {
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if (wq->name.hash == qstr->hash &&
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wq->name.len == qstr->len &&
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wq->name.name &&
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!memcmp(wq->name.name, qstr->name, qstr->len))
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break;
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}
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return wq;
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}
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/*
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* Check if we have a valid request.
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* Returns
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* 1 if the request should continue.
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* In this case we can return an autofs_wait_queue entry if one is
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* found or NULL to idicate a new wait needs to be created.
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* 0 or a negative errno if the request shouldn't continue.
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*/
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static int validate_request(struct autofs_wait_queue **wait,
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struct autofs_sb_info *sbi,
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struct qstr *qstr,
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struct dentry*dentry, enum autofs_notify notify)
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{
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struct autofs_wait_queue *wq;
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struct autofs_info *ino;
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/* Wait in progress, continue; */
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wq = autofs4_find_wait(sbi, qstr);
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if (wq) {
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*wait = wq;
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return 1;
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}
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*wait = NULL;
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/* If we don't yet have any info this is a new request */
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ino = autofs4_dentry_ino(dentry);
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if (!ino)
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return 1;
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/*
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* If we've been asked to wait on an existing expire (NFY_NONE)
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* but there is no wait in the queue ...
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*/
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if (notify == NFY_NONE) {
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/*
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* Either we've betean the pending expire to post it's
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* wait or it finished while we waited on the mutex.
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* So we need to wait till either, the wait appears
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* or the expire finishes.
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*/
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while (ino->flags & AUTOFS_INF_EXPIRING) {
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mutex_unlock(&sbi->wq_mutex);
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schedule_timeout_interruptible(HZ/10);
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if (mutex_lock_interruptible(&sbi->wq_mutex))
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return -EINTR;
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wq = autofs4_find_wait(sbi, qstr);
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if (wq) {
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*wait = wq;
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return 1;
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}
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}
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/*
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* Not ideal but the status has already gone. Of the two
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* cases where we wait on NFY_NONE neither depend on the
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* return status of the wait.
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*/
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return 0;
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}
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/*
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* If we've been asked to trigger a mount and the request
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* completed while we waited on the mutex ...
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*/
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if (notify == NFY_MOUNT) {
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struct dentry *new = NULL;
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int valid = 1;
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/*
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* If the dentry was successfully mounted while we slept
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* on the wait queue mutex we can return success. If it
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* isn't mounted (doesn't have submounts for the case of
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* a multi-mount with no mount at it's base) we can
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* continue on and create a new request.
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*/
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if (!IS_ROOT(dentry)) {
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if (dentry->d_inode && d_unhashed(dentry)) {
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struct dentry *parent = dentry->d_parent;
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new = d_lookup(parent, &dentry->d_name);
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if (new)
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dentry = new;
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}
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}
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if (have_submounts(dentry))
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valid = 0;
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if (new)
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dput(new);
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return valid;
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}
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return 1;
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}
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int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
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enum autofs_notify notify)
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{
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struct autofs_wait_queue *wq;
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struct qstr qstr;
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char *name;
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int status, ret, type;
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/* In catatonic mode, we don't wait for nobody */
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if (sbi->catatonic)
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return -ENOENT;
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if (!dentry->d_inode) {
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/*
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* A wait for a negative dentry is invalid for certain
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* cases. A direct or offset mount "always" has its mount
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* point directory created and so the request dentry must
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* be positive or the map key doesn't exist. The situation
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* is very similar for indirect mounts except only dentrys
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* in the root of the autofs file system may be negative.
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*/
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if (autofs_type_trigger(sbi->type))
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return -ENOENT;
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else if (!IS_ROOT(dentry->d_parent))
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return -ENOENT;
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}
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name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
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if (!name)
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return -ENOMEM;
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/* If this is a direct mount request create a dummy name */
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if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
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qstr.len = sprintf(name, "%p", dentry);
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else {
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qstr.len = autofs4_getpath(sbi, dentry, &name);
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if (!qstr.len) {
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kfree(name);
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return -ENOENT;
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}
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}
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qstr.name = name;
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qstr.hash = full_name_hash(name, qstr.len);
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if (mutex_lock_interruptible(&sbi->wq_mutex)) {
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kfree(qstr.name);
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return -EINTR;
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}
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ret = validate_request(&wq, sbi, &qstr, dentry, notify);
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if (ret <= 0) {
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if (ret == 0)
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mutex_unlock(&sbi->wq_mutex);
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kfree(qstr.name);
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return ret;
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}
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if (!wq) {
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/* Create a new wait queue */
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wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
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if (!wq) {
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kfree(qstr.name);
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mutex_unlock(&sbi->wq_mutex);
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return -ENOMEM;
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}
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wq->wait_queue_token = autofs4_next_wait_queue;
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if (++autofs4_next_wait_queue == 0)
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autofs4_next_wait_queue = 1;
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wq->next = sbi->queues;
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sbi->queues = wq;
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init_waitqueue_head(&wq->queue);
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memcpy(&wq->name, &qstr, sizeof(struct qstr));
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wq->dev = autofs4_get_dev(sbi);
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wq->ino = autofs4_get_ino(sbi);
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wq->uid = current_uid();
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wq->gid = current_gid();
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wq->pid = current->pid;
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wq->tgid = current->tgid;
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wq->status = -EINTR; /* Status return if interrupted */
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wq->wait_ctr = 2;
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mutex_unlock(&sbi->wq_mutex);
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if (sbi->version < 5) {
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if (notify == NFY_MOUNT)
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type = autofs_ptype_missing;
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else
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type = autofs_ptype_expire_multi;
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} else {
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if (notify == NFY_MOUNT)
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type = autofs_type_trigger(sbi->type) ?
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autofs_ptype_missing_direct :
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autofs_ptype_missing_indirect;
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else
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type = autofs_type_trigger(sbi->type) ?
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autofs_ptype_expire_direct :
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autofs_ptype_expire_indirect;
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}
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DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
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(unsigned long) wq->wait_queue_token, wq->name.len,
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wq->name.name, notify);
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/* autofs4_notify_daemon() may block */
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autofs4_notify_daemon(sbi, wq, type);
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} else {
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wq->wait_ctr++;
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mutex_unlock(&sbi->wq_mutex);
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kfree(qstr.name);
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DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
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(unsigned long) wq->wait_queue_token, wq->name.len,
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wq->name.name, notify);
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}
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/*
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* wq->name.name is NULL iff the lock is already released
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* or the mount has been made catatonic.
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*/
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if (wq->name.name) {
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/* Block all but "shutdown" signals while waiting */
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sigset_t oldset;
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unsigned long irqflags;
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spin_lock_irqsave(¤t->sighand->siglock, irqflags);
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oldset = current->blocked;
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siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
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recalc_sigpending();
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spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
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wait_event_interruptible(wq->queue, wq->name.name == NULL);
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spin_lock_irqsave(¤t->sighand->siglock, irqflags);
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current->blocked = oldset;
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recalc_sigpending();
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spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
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} else {
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DPRINTK("skipped sleeping");
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}
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status = wq->status;
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/*
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* For direct and offset mounts we need to track the requester's
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* uid and gid in the dentry info struct. This is so it can be
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* supplied, on request, by the misc device ioctl interface.
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* This is needed during daemon resatart when reconnecting
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* to existing, active, autofs mounts. The uid and gid (and
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* related string values) may be used for macro substitution
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* in autofs mount maps.
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*/
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if (!status) {
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struct autofs_info *ino;
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struct dentry *de = NULL;
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/* direct mount or browsable map */
|
|
ino = autofs4_dentry_ino(dentry);
|
|
if (!ino) {
|
|
/* If not lookup actual dentry used */
|
|
de = d_lookup(dentry->d_parent, &dentry->d_name);
|
|
if (de)
|
|
ino = autofs4_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 autofs4_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_interruptible(&wq->queue);
|
|
if (!--wq->wait_ctr)
|
|
kfree(wq);
|
|
mutex_unlock(&sbi->wq_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|