1 files changed, 180 insertions, 87 deletions

diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 75e5955c3f6d..35216d18d8b5 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -28,6 +28,12 @@ void autofs4_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;
+        }
+
         DPRINTK("entering catatonic mode");
 
         sbi->catatonic = 1;
@@ -36,13 +42,18 @@ void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
         while (wq) {
                 nwq = wq->next;
                 wq->status = -ENOENT; /* Magic is gone - report failure */
-                kfree(wq->name);
-                wq->name = NULL;
+                if (wq->name.name) {
+                        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 autofs4_write(struct file *file, const void *addr, int bytes)
@@ -89,10 +100,11 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
                 union autofs_packet_union v4_pkt;
                 union autofs_v5_packet_union v5_pkt;
         } pkt;
+        struct file *pipe = NULL;
         size_t pktsz;
 
         DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
-                wq->wait_queue_token, wq->len, wq->name, type);
+                wq->wait_queue_token, wq->name.len, wq->name.name, type);
 
         memset(&pkt,0,sizeof pkt); /* For security reasons */
 
@@ -107,9 +119,9 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
                 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';
+                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:
@@ -119,9 +131,9 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
                 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';
+                ep->len = wq->name.len;
+                memcpy(ep->name, wq->name.name, wq->name.len);
+                ep->name[wq->name.len] = '\0';
                 break;
         }
         /*
@@ -138,9 +150,9 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
                 pktsz = sizeof(*packet);
 
                 packet->wait_queue_token = wq->wait_queue_token;
-                packet->len = wq->len;
-                memcpy(packet->name, wq->name, wq->len);
-                packet->name[wq->len] = '\0';
+                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 = wq->uid;
@@ -154,8 +166,19 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
                 return;
         }
 
-        if (autofs4_write(sbi->pipe, &pkt, pktsz))
-                autofs4_catatonic_mode(sbi);
+        /* Check if we have become catatonic */
+        mutex_lock(&sbi->wq_mutex);
+        if (!sbi->catatonic) {
+                pipe = sbi->pipe;
+                get_file(pipe);
+        }
+        mutex_unlock(&sbi->wq_mutex);
+
+        if (pipe) {
+                if (autofs4_write(pipe, &pkt, pktsz))
+                        autofs4_catatonic_mode(sbi);
+                fput(pipe);
+        }
 }
 
 static int autofs4_getpath(struct autofs_sb_info *sbi,
@@ -191,58 +214,55 @@ static int autofs4_getpath(struct autofs_sb_info *sbi,
 }
 
 static struct autofs_wait_queue *
-autofs4_find_wait(struct autofs_sb_info *sbi,
-                  char *name, unsigned int hash, unsigned int len)
+autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
 {
         struct autofs_wait_queue *wq;
 
         for (wq = sbi->queues; wq; wq = wq->next) {
-                if (wq->hash == hash &&
-                    wq->len == len &&
-                    wq->name && !memcmp(wq->name, name, len))
+                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;
 }
 
-int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
-                enum autofs_notify notify)
+/*
+ * 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,
+                            struct qstr *qstr,
+                            struct dentry*dentry, enum autofs_notify notify)
 {
-        struct autofs_info *ino;
         struct autofs_wait_queue *wq;
-        char *name;
-        unsigned int len = 0;
-        unsigned int hash = 0;
-        int status, type;
-
-        /* 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;
+        struct autofs_info *ino;
 
-        /* If this is a direct mount request create a dummy name */
-        if (IS_ROOT(dentry) && (sbi->type & AUTOFS_TYPE_DIRECT))
-                len = sprintf(name, "%p", dentry);
-        else {
-                len = autofs4_getpath(sbi, dentry, &name);
-                if (!len) {
-                        kfree(name);
-                        return -ENOENT;
-                }
+        /* Wait in progress, continue; */
+        wq = autofs4_find_wait(sbi, qstr);
+        if (wq) {
+                *wait = wq;
+                return 1;
         }
-        hash = full_name_hash(name, len);
 
-        if (mutex_lock_interruptible(&sbi->wq_mutex)) {
-                kfree(name);
-                return -EINTR;
-        }
+        *wait = NULL;
 
-        wq = autofs4_find_wait(sbi, name, hash, len);
+        /* If we don't yet have any info this is a new request */
         ino = autofs4_dentry_ino(dentry);
-        if (!wq && ino && notify == NFY_NONE) {
+        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.
@@ -253,13 +273,14 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                 while (ino->flags & AUTOFS_INF_EXPIRING) {
                         mutex_unlock(&sbi->wq_mutex);
                         schedule_timeout_interruptible(HZ/10);
-                        if (mutex_lock_interruptible(&sbi->wq_mutex)) {
-                                kfree(name);
+                        if (mutex_lock_interruptible(&sbi->wq_mutex))
                                 return -EINTR;
+
+                        wq = autofs4_find_wait(sbi, qstr);
+                        if (wq) {
+                                *wait = wq;
+                                return 1;
                         }
-                        wq = autofs4_find_wait(sbi, name, hash, len);
-                        if (wq)
-                                break;
                 }
 
                 /*
@@ -267,18 +288,96 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                  * cases where we wait on NFY_NONE neither depend on the
                  * return status of the wait.
                  */
-                if (!wq) {
+                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) {
+                /*
+                 * If the dentry isn't hashed just go ahead and try the
+                 * mount again with a new wait (not much else we can do).
+                */
+                if (!d_unhashed(dentry)) {
+                        /*
+                         * But if the dentry is hashed, that means that we
+                         * got here through the revalidate path.  Thus, we
+                         * need to check if the dentry has been mounted
+                         * while we waited on the wq_mutex. If it has,
+                         * simply return success.
+                         */
+                        if (d_mountpoint(dentry))
+                                return 0;
+                }
+        }
+
+        return 1;
+}
+
+int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
+                enum autofs_notify notify)
+{
+        struct autofs_wait_queue *wq;
+        struct qstr qstr;
+        char *name;
+        int status, ret, type;
+
+        /* In catatonic mode, we don't wait for nobody */
+        if (sbi->catatonic)
+                return -ENOENT;
+
+        if (!dentry->d_inode) {
+                /*
+                 * 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 (sbi->type & (AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET))
+                        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) && (sbi->type & AUTOFS_TYPE_DIRECT))
+                qstr.len = sprintf(name, "%p", dentry);
+        else {
+                qstr.len = autofs4_getpath(sbi, dentry, &name);
+                if (!qstr.len) {
                         kfree(name);
-                        mutex_unlock(&sbi->wq_mutex);
-                        return 0;
+                        return -ENOENT;
                 }
         }
+        qstr.name = name;
+        qstr.hash = full_name_hash(name, qstr.len);
+
+        if (mutex_lock_interruptible(&sbi->wq_mutex)) {
+                kfree(qstr.name);
+                return -EINTR;
+        }
+
+        ret = validate_request(&wq, sbi, &qstr, dentry, notify);
+        if (ret <= 0) {
+                if (ret == 0)
+                        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(name);
+                        kfree(qstr.name);
                         mutex_unlock(&sbi->wq_mutex);
                         return -ENOMEM;
                 }
@@ -289,9 +388,7 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                 wq->next = sbi->queues;
                 sbi->queues = wq;
                 init_waitqueue_head(&wq->queue);
-                wq->hash = hash;
-                wq->name = name;
-                wq->len = len;
+                memcpy(&wq->name, &qstr, sizeof(struct qstr));
                 wq->dev = autofs4_get_dev(sbi);
                 wq->ino = autofs4_get_ino(sbi);
                 wq->uid = current->uid;
@@ -299,7 +396,7 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                 wq->pid = current->pid;
                 wq->tgid = current->tgid;
                 wq->status = -EINTR; /* Status return if interrupted */
-                atomic_set(&wq->wait_ctr, 2);
+                wq->wait_ctr = 2;
                 mutex_unlock(&sbi->wq_mutex);
 
                 if (sbi->version < 5) {
@@ -319,28 +416,25 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                 }
 
                 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
-                        (unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
+                        (unsigned long) wq->wait_queue_token, wq->name.len,
+                        wq->name.name, notify);
 
                 /* autofs4_notify_daemon() may block */
                 autofs4_notify_daemon(sbi, wq, type);
         } else {
-                atomic_inc(&wq->wait_ctr);
+                wq->wait_ctr++;
                 mutex_unlock(&sbi->wq_mutex);
-                kfree(name);
+                kfree(qstr.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;
-                kfree(wq->name);
-                wq->name = NULL;
+                        (unsigned long) wq->wait_queue_token, wq->name.len,
+                        wq->name.name, notify);
         }
 
-        if (wq->name) {
+        /*
+         * wq->name.name is NULL iff the lock is already released
+         * or the mount has been made catatonic.
+         */
+        if (wq->name.name) {
                 /* Block all but "shutdown" signals while waiting */
                 sigset_t oldset;
                 unsigned long irqflags;
@@ -351,7 +445,7 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                 recalc_sigpending();
                 spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
 
-                wait_event_interruptible(wq->queue, wq->name == NULL);
+                wait_event_interruptible(wq->queue, wq->name.name == NULL);
 
                 spin_lock_irqsave(&current->sighand->siglock, irqflags);
                 current->blocked = oldset;
@@ -364,8 +458,10 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
         status = wq->status;
 
         /* Are we the last process to need status? */
-        if (atomic_dec_and_test(&wq->wait_ctr))
+        mutex_lock(&sbi->wq_mutex);
+        if (!--wq->wait_ctr)
                 kfree(wq);
+        mutex_unlock(&sbi->wq_mutex);
 
         return status;
 }
@@ -387,16 +483,13 @@ int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_tok
         }
 
         *wql = wq->next;        /* Unlink from chain */
-        mutex_unlock(&sbi->wq_mutex);
-        kfree(wq->name);
-        wq->name = NULL;        /* Do not wait on this queue */
-
+        kfree(wq->name.name);
+        wq->name.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? */
+        wake_up_interruptible(&wq->queue);
+        if (!--wq->wait_ctr)
                 kfree(wq);
-        else
-                wake_up_interruptible(&wq->queue);
+        mutex_unlock(&sbi->wq_mutex);
 
         return 0;
 }