![Linus Torvalds](/assets/img/avatar_default.png)
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
207 lines
5.3 KiB
C
207 lines
5.3 KiB
C
/* -*- linux-c -*- --------------------------------------------------------- *
|
|
*
|
|
* linux/fs/autofs/waitq.c
|
|
*
|
|
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
|
|
*
|
|
* 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/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;
|
|
|
|
/* These are the signals we allow interrupting a pending mount */
|
|
#define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
|
|
|
|
void autofs_catatonic_mode(struct autofs_sb_info *sbi)
|
|
{
|
|
struct autofs_wait_queue *wq, *nwq;
|
|
|
|
DPRINTK(("autofs: 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);
|
|
wq->name = NULL;
|
|
wake_up(&wq->queue);
|
|
wq = nwq;
|
|
}
|
|
fput(sbi->pipe); /* Close the pipe */
|
|
autofs_hash_dputall(&sbi->dirhash); /* Remove all dentry pointers */
|
|
}
|
|
|
|
static int autofs_write(struct file *file, const void *addr, int bytes)
|
|
{
|
|
unsigned long sigpipe, flags;
|
|
mm_segment_t fs;
|
|
const char *data = (const char *)addr;
|
|
ssize_t wr = 0;
|
|
|
|
/** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/
|
|
|
|
sigpipe = sigismember(¤t->pending.signal, SIGPIPE);
|
|
|
|
/* Save pointer to user space and point back to kernel space */
|
|
fs = get_fs();
|
|
set_fs(KERNEL_DS);
|
|
|
|
while (bytes &&
|
|
(wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) {
|
|
data += wr;
|
|
bytes -= wr;
|
|
}
|
|
|
|
set_fs(fs);
|
|
|
|
/* 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);
|
|
}
|
|
|
|
return (bytes > 0);
|
|
}
|
|
|
|
static void autofs_notify_daemon(struct autofs_sb_info *sbi, struct autofs_wait_queue *wq)
|
|
{
|
|
struct autofs_packet_missing pkt;
|
|
|
|
DPRINTK(("autofs_wait: wait id = 0x%08lx, name = ", wq->wait_queue_token));
|
|
autofs_say(wq->name,wq->len);
|
|
|
|
memset(&pkt,0,sizeof pkt); /* For security reasons */
|
|
|
|
pkt.hdr.proto_version = AUTOFS_PROTO_VERSION;
|
|
pkt.hdr.type = autofs_ptype_missing;
|
|
pkt.wait_queue_token = wq->wait_queue_token;
|
|
pkt.len = wq->len;
|
|
memcpy(pkt.name, wq->name, pkt.len);
|
|
pkt.name[pkt.len] = '\0';
|
|
|
|
if ( autofs_write(sbi->pipe,&pkt,sizeof(struct autofs_packet_missing)) )
|
|
autofs_catatonic_mode(sbi);
|
|
}
|
|
|
|
int autofs_wait(struct autofs_sb_info *sbi, struct qstr *name)
|
|
{
|
|
struct autofs_wait_queue *wq;
|
|
int status;
|
|
|
|
/* In catatonic mode, we don't wait for nobody */
|
|
if ( sbi->catatonic )
|
|
return -ENOENT;
|
|
|
|
/* We shouldn't be able to get here, but just in case */
|
|
if ( name->len > NAME_MAX )
|
|
return -ENOENT;
|
|
|
|
for ( wq = sbi->queues ; wq ; wq = wq->next ) {
|
|
if ( wq->hash == name->hash &&
|
|
wq->len == name->len &&
|
|
wq->name && !memcmp(wq->name,name->name,name->len) )
|
|
break;
|
|
}
|
|
|
|
if ( !wq ) {
|
|
/* Create a new wait queue */
|
|
wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
|
|
if ( !wq )
|
|
return -ENOMEM;
|
|
|
|
wq->name = kmalloc(name->len,GFP_KERNEL);
|
|
if ( !wq->name ) {
|
|
kfree(wq);
|
|
return -ENOMEM;
|
|
}
|
|
wq->wait_queue_token = autofs_next_wait_queue++;
|
|
init_waitqueue_head(&wq->queue);
|
|
wq->hash = name->hash;
|
|
wq->len = name->len;
|
|
wq->status = -EINTR; /* Status return if interrupted */
|
|
memcpy(wq->name, name->name, name->len);
|
|
wq->next = sbi->queues;
|
|
sbi->queues = wq;
|
|
|
|
/* autofs_notify_daemon() may block */
|
|
wq->wait_ctr = 2;
|
|
autofs_notify_daemon(sbi,wq);
|
|
} else
|
|
wq->wait_ctr++;
|
|
|
|
/* wq->name is NULL if and only if the lock is already released */
|
|
|
|
if ( sbi->catatonic ) {
|
|
/* We might have slept, so check again for catatonic mode */
|
|
wq->status = -ENOENT;
|
|
if ( wq->name ) {
|
|
kfree(wq->name);
|
|
wq->name = NULL;
|
|
}
|
|
}
|
|
|
|
if ( wq->name ) {
|
|
/* Block all but "shutdown" signals while waiting */
|
|
sigset_t sigmask;
|
|
|
|
siginitsetinv(&sigmask, SHUTDOWN_SIGS);
|
|
sigprocmask(SIG_BLOCK, &sigmask, &sigmask);
|
|
|
|
interruptible_sleep_on(&wq->queue);
|
|
|
|
sigprocmask(SIG_SETMASK, &sigmask, NULL);
|
|
} else {
|
|
DPRINTK(("autofs_wait: skipped sleeping\n"));
|
|
}
|
|
|
|
status = wq->status;
|
|
|
|
if ( ! --wq->wait_ctr ) /* Are we the last process to need status? */
|
|
kfree(wq);
|
|
|
|
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;
|
|
|
|
for ( wql = &sbi->queues ; (wq = *wql) != 0 ; wql = &wq->next ) {
|
|
if ( wq->wait_queue_token == wait_queue_token )
|
|
break;
|
|
}
|
|
if ( !wq )
|
|
return -EINVAL;
|
|
|
|
*wql = wq->next; /* Unlink from chain */
|
|
kfree(wq->name);
|
|
wq->name = NULL; /* Do not wait on this queue */
|
|
|
|
wq->status = status;
|
|
|
|
if ( ! --wq->wait_ctr ) /* Is anyone still waiting for this guy? */
|
|
kfree(wq);
|
|
else
|
|
wake_up(&wq->queue);
|
|
|
|
return 0;
|
|
}
|
|
|