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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/autofs4/waitq.c
downloadvexpress-lsk-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2
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!
Diffstat (limited to 'fs/autofs4/waitq.c')
-rw-r--r--fs/autofs4/waitq.c303
1 files changed, 303 insertions, 0 deletions
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
new file mode 100644
index 00000000000..1ab24a662e0
--- /dev/null
+++ b/fs/autofs4/waitq.c
@@ -0,0 +1,303 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/fs/autofs/waitq.c
+ *
+ * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ * Copyright 2001-2003 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/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 autofs4_next_wait_queue = 1;
+
+/* These are the signals we allow interrupting a pending mount */
+#define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
+
+void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
+{
+ struct autofs_wait_queue *wq, *nwq;
+
+ DPRINTK("entering catatonic mode");
+
+ 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_interruptible(&wq->queue);
+ wq = nwq;
+ }
+ if (sbi->pipe) {
+ fput(sbi->pipe); /* Close the pipe */
+ sbi->pipe = NULL;
+ }
+
+ shrink_dcache_sb(sbi->sb);
+}
+
+static int autofs4_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(&current->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(&current->sighand->siglock, flags);
+ sigdelset(&current->pending.signal, SIGPIPE);
+ recalc_sigpending();
+ spin_unlock_irqrestore(&current->sighand->siglock, flags);
+ }
+
+ return (bytes > 0);
+}
+
+static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
+ struct autofs_wait_queue *wq,
+ int type)
+{
+ union autofs_packet_union pkt;
+ size_t pktsz;
+
+ DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
+ wq->wait_queue_token, wq->len, wq->name, type);
+
+ memset(&pkt,0,sizeof pkt); /* For security reasons */
+
+ pkt.hdr.proto_version = sbi->version;
+ pkt.hdr.type = type;
+ if (type == autofs_ptype_missing) {
+ struct autofs_packet_missing *mp = &pkt.missing;
+
+ pktsz = sizeof(*mp);
+
+ mp->wait_queue_token = wq->wait_queue_token;
+ mp->len = wq->len;
+ memcpy(mp->name, wq->name, wq->len);
+ mp->name[wq->len] = '\0';
+ } else if (type == autofs_ptype_expire_multi) {
+ struct autofs_packet_expire_multi *ep = &pkt.expire_multi;
+
+ pktsz = sizeof(*ep);
+
+ ep->wait_queue_token = wq->wait_queue_token;
+ ep->len = wq->len;
+ memcpy(ep->name, wq->name, wq->len);
+ ep->name[wq->len] = '\0';
+ } else {
+ printk("autofs4_notify_daemon: bad type %d!\n", type);
+ return;
+ }
+
+ if (autofs4_write(sbi->pipe, &pkt, pktsz))
+ autofs4_catatonic_mode(sbi);
+}
+
+static int autofs4_getpath(struct autofs_sb_info *sbi,
+ struct dentry *dentry, char **name)
+{
+ struct dentry *root = sbi->sb->s_root;
+ struct dentry *tmp;
+ char *buf = *name;
+ char *p;
+ int len = 0;
+
+ spin_lock(&dcache_lock);
+ for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
+ len += tmp->d_name.len + 1;
+
+ if (--len > NAME_MAX) {
+ spin_unlock(&dcache_lock);
+ 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(&dcache_lock);
+
+ return len;
+}
+
+int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
+ enum autofs_notify notify)
+{
+ struct autofs_wait_queue *wq;
+ char *name;
+ int len, status;
+
+ /* In catatonic mode, we don't wait for nobody */
+ if ( sbi->catatonic )
+ return -ENOENT;
+
+ name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+
+ len = autofs4_getpath(sbi, dentry, &name);
+ if (!len) {
+ kfree(name);
+ return -ENOENT;
+ }
+
+ if (down_interruptible(&sbi->wq_sem)) {
+ kfree(name);
+ return -EINTR;
+ }
+
+ for (wq = sbi->queues ; wq ; wq = wq->next) {
+ if (wq->hash == dentry->d_name.hash &&
+ wq->len == len &&
+ wq->name && !memcmp(wq->name, name, len))
+ break;
+ }
+
+ if ( !wq ) {
+ /* Create a new wait queue */
+ wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
+ if ( !wq ) {
+ kfree(name);
+ up(&sbi->wq_sem);
+ return -ENOMEM;
+ }
+
+ wq->wait_queue_token = autofs4_next_wait_queue;
+ if (++autofs4_next_wait_queue == 0)
+ autofs4_next_wait_queue = 1;
+ wq->next = sbi->queues;
+ sbi->queues = wq;
+ init_waitqueue_head(&wq->queue);
+ wq->hash = dentry->d_name.hash;
+ wq->name = name;
+ wq->len = len;
+ wq->status = -EINTR; /* Status return if interrupted */
+ atomic_set(&wq->wait_ctr, 2);
+ up(&sbi->wq_sem);
+
+ DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d",
+ (unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
+ /* autofs4_notify_daemon() may block */
+ if (notify != NFY_NONE) {
+ autofs4_notify_daemon(sbi,wq,
+ notify == NFY_MOUNT ?
+ autofs_ptype_missing :
+ autofs_ptype_expire_multi);
+ }
+ } else {
+ atomic_inc(&wq->wait_ctr);
+ up(&sbi->wq_sem);
+ kfree(name);
+ DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
+ (unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
+ }
+
+ /* 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 oldset;
+ unsigned long irqflags;
+
+ spin_lock_irqsave(&current->sighand->siglock, irqflags);
+ oldset = current->blocked;
+ siginitsetinv(&current->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
+ recalc_sigpending();
+ spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
+
+ wait_event_interruptible(wq->queue, wq->name == NULL);
+
+ spin_lock_irqsave(&current->sighand->siglock, irqflags);
+ current->blocked = oldset;
+ recalc_sigpending();
+ spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
+ } else {
+ DPRINTK("skipped sleeping");
+ }
+
+ status = wq->status;
+
+ /* Are we the last process to need status? */
+ if (atomic_dec_and_test(&wq->wait_ctr))
+ kfree(wq);
+
+ 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;
+
+ down(&sbi->wq_sem);
+ for ( wql = &sbi->queues ; (wq = *wql) != 0 ; wql = &wq->next ) {
+ if ( wq->wait_queue_token == wait_queue_token )
+ break;
+ }
+
+ if ( !wq ) {
+ up(&sbi->wq_sem);
+ return -EINVAL;
+ }
+
+ *wql = wq->next; /* Unlink from chain */
+ up(&sbi->wq_sem);
+ kfree(wq->name);
+ wq->name = NULL; /* Do not wait on this queue */
+
+ wq->status = status;
+
+ if (atomic_dec_and_test(&wq->wait_ctr)) /* Is anyone still waiting for this guy? */
+ kfree(wq);
+ else
+ wake_up_interruptible(&wq->queue);
+
+ return 0;
+}
+