X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=fs%2Ffuse%2Fdev.c;h=357764d85ff1e0cc81723f4006f78479e5164fc8;hb=c9c64155f5a81b4b41e98f9fb9c464a565c1bf72;hp=fe3adf589174dfda727348d9fe92add73d4a0088;hpb=bafa96541b250a7051e3fbc5de6e8369daf8ffec;p=cascardo%2Flinux.git

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index fe3adf589174..357764d85ff1 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -19,7 +19,7 @@
 
 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
 
-static kmem_cache_t *fuse_req_cachep;
+static struct kmem_cache *fuse_req_cachep;
 
 static struct fuse_conn *fuse_get_conn(struct file *file)
 {
@@ -34,13 +34,14 @@ static void fuse_request_init(struct fuse_req *req)
 {
 	memset(req, 0, sizeof(*req));
 	INIT_LIST_HEAD(&req->list);
+	INIT_LIST_HEAD(&req->intr_entry);
 	init_waitqueue_head(&req->waitq);
 	atomic_set(&req->count, 1);
 }
 
 struct fuse_req *fuse_request_alloc(void)
 {
-	struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, SLAB_KERNEL);
+	struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
 	if (req)
 		fuse_request_init(req);
 	return req;
@@ -76,6 +77,13 @@ static void __fuse_put_request(struct fuse_req *req)
 	atomic_dec(&req->count);
 }
 
+static void fuse_req_init_context(struct fuse_req *req)
+{
+	req->in.h.uid = current->fsuid;
+	req->in.h.gid = current->fsgid;
+	req->in.h.pid = current->pid;
+}
+
 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
 {
 	struct fuse_req *req;
@@ -100,9 +108,7 @@ struct fuse_req *fuse_get_req(struct fuse_conn *fc)
 	if (!req)
 		goto out;
 
-	req->in.h.uid = current->fsuid;
-	req->in.h.gid = current->fsgid;
-	req->in.h.pid = current->pid;
+	fuse_req_init_context(req);
 	req->waiting = 1;
 	return req;
 
@@ -111,18 +117,93 @@ struct fuse_req *fuse_get_req(struct fuse_conn *fc)
 	return ERR_PTR(err);
 }
 
+/*
+ * Return request in fuse_file->reserved_req.  However that may
+ * currently be in use.  If that is the case, wait for it to become
+ * available.
+ */
+static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
+					 struct file *file)
+{
+	struct fuse_req *req = NULL;
+	struct fuse_file *ff = file->private_data;
+
+	do {
+		wait_event(fc->blocked_waitq, ff->reserved_req);
+		spin_lock(&fc->lock);
+		if (ff->reserved_req) {
+			req = ff->reserved_req;
+			ff->reserved_req = NULL;
+			get_file(file);
+			req->stolen_file = file;
+		}
+		spin_unlock(&fc->lock);
+	} while (!req);
+
+	return req;
+}
+
+/*
+ * Put stolen request back into fuse_file->reserved_req
+ */
+static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
+{
+	struct file *file = req->stolen_file;
+	struct fuse_file *ff = file->private_data;
+
+	spin_lock(&fc->lock);
+	fuse_request_init(req);
+	BUG_ON(ff->reserved_req);
+	ff->reserved_req = req;
+	wake_up(&fc->blocked_waitq);
+	spin_unlock(&fc->lock);
+	fput(file);
+}
+
+/*
+ * Gets a requests for a file operation, always succeeds
+ *
+ * This is used for sending the FLUSH request, which must get to
+ * userspace, due to POSIX locks which may need to be unlocked.
+ *
+ * If allocation fails due to OOM, use the reserved request in
+ * fuse_file.
+ *
+ * This is very unlikely to deadlock accidentally, since the
+ * filesystem should not have it's own file open.  If deadlock is
+ * intentional, it can still be broken by "aborting" the filesystem.
+ */
+struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
+{
+	struct fuse_req *req;
+
+	atomic_inc(&fc->num_waiting);
+	wait_event(fc->blocked_waitq, !fc->blocked);
+	req = fuse_request_alloc();
+	if (!req)
+		req = get_reserved_req(fc, file);
+
+	fuse_req_init_context(req);
+	req->waiting = 1;
+	return req;
+}
+
 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 {
 	if (atomic_dec_and_test(&req->count)) {
 		if (req->waiting)
 			atomic_dec(&fc->num_waiting);
-		fuse_request_free(req);
+
+		if (req->stolen_file)
+			put_reserved_req(fc, req);
+		else
+			fuse_request_free(req);
 	}
 }
 
 /*
  * This function is called when a request is finished.  Either a reply
- * has arrived or it was interrupted (and not yet sent) or some error
+ * has arrived or it was aborted (and not yet sent) or some error
  * occurred during communication with userspace, or the device file
  * was closed.  The requester thread is woken up (if still waiting),
  * the 'end' callback is called if given, else the reference to the
@@ -131,10 +212,12 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
  * Called with fc->lock, unlocks it
  */
 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
+	__releases(fc->lock)
 {
 	void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
 	req->end = NULL;
 	list_del(&req->list);
+	list_del(&req->intr_entry);
 	req->state = FUSE_REQ_FINISHED;
 	if (req->background) {
 		if (fc->num_background == FUSE_MAX_BACKGROUND) {
@@ -155,28 +238,63 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 		fuse_put_request(fc, req);
 }
 
+static void wait_answer_interruptible(struct fuse_conn *fc,
+				      struct fuse_req *req)
+{
+	if (signal_pending(current))
+		return;
+
+	spin_unlock(&fc->lock);
+	wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
+	spin_lock(&fc->lock);
+}
+
+static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
+{
+	list_add_tail(&req->intr_entry, &fc->interrupts);
+	wake_up(&fc->waitq);
+	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
+}
+
 /* Called with fc->lock held.  Releases, and then reacquires it. */
 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 {
-	sigset_t oldset;
+	if (!fc->no_interrupt) {
+		/* Any signal may interrupt this */
+		wait_answer_interruptible(fc, req);
 
-	spin_unlock(&fc->lock);
-	if (req->force)
+		if (req->aborted)
+			goto aborted;
+		if (req->state == FUSE_REQ_FINISHED)
+			return;
+
+		req->interrupted = 1;
+		if (req->state == FUSE_REQ_SENT)
+			queue_interrupt(fc, req);
+	}
+
+	if (req->force) {
+		spin_unlock(&fc->lock);
 		wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
-	else {
+		spin_lock(&fc->lock);
+	} else {
+		sigset_t oldset;
+
+		/* Only fatal signals may interrupt this */
 		block_sigs(&oldset);
-		wait_event_interruptible(req->waitq,
-					 req->state == FUSE_REQ_FINISHED);
+		wait_answer_interruptible(fc, req);
 		restore_sigs(&oldset);
 	}
-	spin_lock(&fc->lock);
-	if (req->state == FUSE_REQ_FINISHED && !req->interrupted)
-		return;
 
-	if (!req->interrupted) {
-		req->out.h.error = -EINTR;
-		req->interrupted = 1;
-	}
+	if (req->aborted)
+		goto aborted;
+	if (req->state == FUSE_REQ_FINISHED)
+ 		return;
+
+	req->out.h.error = -EINTR;
+	req->aborted = 1;
+
+ aborted:
 	if (req->locked) {
 		/* This is uninterruptible sleep, because data is
 		   being copied to/from the buffers of req.  During
@@ -208,13 +326,19 @@ static unsigned len_args(unsigned numargs, struct fuse_arg *args)
 	return nbytes;
 }
 
+static u64 fuse_get_unique(struct fuse_conn *fc)
+ {
+ 	fc->reqctr++;
+ 	/* zero is special */
+ 	if (fc->reqctr == 0)
+ 		fc->reqctr = 1;
+
+	return fc->reqctr;
+}
+
 static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
 {
-	fc->reqctr++;
-	/* zero is special */
-	if (fc->reqctr == 0)
-		fc->reqctr = 1;
-	req->in.h.unique = fc->reqctr;
+	req->in.h.unique = fuse_get_unique(fc);
 	req->in.h.len = sizeof(struct fuse_in_header) +
 		len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
 	list_add_tail(&req->list, &fc->pending);
@@ -227,9 +351,6 @@ static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
 	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 }
 
-/*
- * This can only be interrupted by a SIGKILL
- */
 void request_send(struct fuse_conn *fc, struct fuse_req *req)
 {
 	req->isreply = 1;
@@ -281,14 +402,14 @@ void request_send_background(struct fuse_conn *fc, struct fuse_req *req)
 /*
  * Lock the request.  Up to the next unlock_request() there mustn't be
  * anything that could cause a page-fault.  If the request was already
- * interrupted bail out.
+ * aborted bail out.
  */
 static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
 {
 	int err = 0;
 	if (req) {
 		spin_lock(&fc->lock);
-		if (req->interrupted)
+		if (req->aborted)
 			err = -ENOENT;
 		else
 			req->locked = 1;
@@ -298,7 +419,7 @@ static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
 }
 
 /*
- * Unlock request.  If it was interrupted during being locked, the
+ * Unlock request.  If it was aborted during being locked, the
  * requester thread is currently waiting for it to be unlocked, so
  * wake it up.
  */
@@ -307,7 +428,7 @@ static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
 	if (req) {
 		spin_lock(&fc->lock);
 		req->locked = 0;
-		if (req->interrupted)
+		if (req->aborted)
 			wake_up(&req->waitq);
 		spin_unlock(&fc->lock);
 	}
@@ -486,13 +607,18 @@ static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
 	return err;
 }
 
+static int request_pending(struct fuse_conn *fc)
+{
+	return !list_empty(&fc->pending) || !list_empty(&fc->interrupts);
+}
+
 /* Wait until a request is available on the pending list */
 static void request_wait(struct fuse_conn *fc)
 {
 	DECLARE_WAITQUEUE(wait, current);
 
 	add_wait_queue_exclusive(&fc->waitq, &wait);
-	while (fc->connected && list_empty(&fc->pending)) {
+	while (fc->connected && !request_pending(fc)) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (signal_pending(current))
 			break;
@@ -505,23 +631,64 @@ static void request_wait(struct fuse_conn *fc)
 	remove_wait_queue(&fc->waitq, &wait);
 }
 
+/*
+ * Transfer an interrupt request to userspace
+ *
+ * Unlike other requests this is assembled on demand, without a need
+ * to allocate a separate fuse_req structure.
+ *
+ * Called with fc->lock held, releases it
+ */
+static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req,
+			       const struct iovec *iov, unsigned long nr_segs)
+	__releases(fc->lock)
+{
+	struct fuse_copy_state cs;
+	struct fuse_in_header ih;
+	struct fuse_interrupt_in arg;
+	unsigned reqsize = sizeof(ih) + sizeof(arg);
+	int err;
+
+	list_del_init(&req->intr_entry);
+	req->intr_unique = fuse_get_unique(fc);
+	memset(&ih, 0, sizeof(ih));
+	memset(&arg, 0, sizeof(arg));
+	ih.len = reqsize;
+	ih.opcode = FUSE_INTERRUPT;
+	ih.unique = req->intr_unique;
+	arg.unique = req->in.h.unique;
+
+	spin_unlock(&fc->lock);
+	if (iov_length(iov, nr_segs) < reqsize)
+		return -EINVAL;
+
+	fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs);
+	err = fuse_copy_one(&cs, &ih, sizeof(ih));
+	if (!err)
+		err = fuse_copy_one(&cs, &arg, sizeof(arg));
+	fuse_copy_finish(&cs);
+
+	return err ? err : reqsize;
+}
+
 /*
  * Read a single request into the userspace filesystem's buffer.  This
  * function waits until a request is available, then removes it from
  * the pending list and copies request data to userspace buffer.  If
- * no reply is needed (FORGET) or request has been interrupted or
- * there was an error during the copying then it's finished by calling
+ * no reply is needed (FORGET) or request has been aborted or there
+ * was an error during the copying then it's finished by calling
  * request_end().  Otherwise add it to the processing list, and set
  * the 'sent' flag.
  */
-static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov,
-			      unsigned long nr_segs, loff_t *off)
+static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
+			      unsigned long nr_segs, loff_t pos)
 {
 	int err;
 	struct fuse_req *req;
 	struct fuse_in *in;
 	struct fuse_copy_state cs;
 	unsigned reqsize;
+	struct file *file = iocb->ki_filp;
 	struct fuse_conn *fc = fuse_get_conn(file);
 	if (!fc)
 		return -EPERM;
@@ -530,7 +697,7 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov,
 	spin_lock(&fc->lock);
 	err = -EAGAIN;
 	if ((file->f_flags & O_NONBLOCK) && fc->connected &&
-	    list_empty(&fc->pending))
+	    !request_pending(fc))
 		goto err_unlock;
 
 	request_wait(fc);
@@ -538,9 +705,15 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov,
 	if (!fc->connected)
 		goto err_unlock;
 	err = -ERESTARTSYS;
-	if (list_empty(&fc->pending))
+	if (!request_pending(fc))
 		goto err_unlock;
 
+	if (!list_empty(&fc->interrupts)) {
+		req = list_entry(fc->interrupts.next, struct fuse_req,
+				 intr_entry);
+		return fuse_read_interrupt(fc, req, iov, nr_segs);
+	}
+
 	req = list_entry(fc->pending.next, struct fuse_req, list);
 	req->state = FUSE_REQ_READING;
 	list_move(&req->list, &fc->io);
@@ -565,10 +738,10 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov,
 	fuse_copy_finish(&cs);
 	spin_lock(&fc->lock);
 	req->locked = 0;
-	if (!err && req->interrupted)
+	if (!err && req->aborted)
 		err = -ENOENT;
 	if (err) {
-		if (!req->interrupted)
+		if (!req->aborted)
 			req->out.h.error = -EIO;
 		request_end(fc, req);
 		return err;
@@ -578,6 +751,8 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov,
 	else {
 		req->state = FUSE_REQ_SENT;
 		list_move_tail(&req->list, &fc->processing);
+		if (req->interrupted)
+			queue_interrupt(fc, req);
 		spin_unlock(&fc->lock);
 	}
 	return reqsize;
@@ -587,15 +762,6 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov,
 	return err;
 }
 
-static ssize_t fuse_dev_read(struct file *file, char __user *buf,
-			     size_t nbytes, loff_t *off)
-{
-	struct iovec iov;
-	iov.iov_len = nbytes;
-	iov.iov_base = buf;
-	return fuse_dev_readv(file, &iov, 1, off);
-}
-
 /* Look up request on processing list by unique ID */
 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
 {
@@ -604,7 +770,7 @@ static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
 	list_for_each(entry, &fc->processing) {
 		struct fuse_req *req;
 		req = list_entry(entry, struct fuse_req, list);
-		if (req->in.h.unique == unique)
+		if (req->in.h.unique == unique || req->intr_unique == unique)
 			return req;
 	}
 	return NULL;
@@ -640,15 +806,15 @@ static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
  * it from the list and copy the rest of the buffer to the request.
  * The request is finished by calling request_end()
  */
-static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov,
-			       unsigned long nr_segs, loff_t *off)
+static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
+			       unsigned long nr_segs, loff_t pos)
 {
 	int err;
 	unsigned nbytes = iov_length(iov, nr_segs);
 	struct fuse_req *req;
 	struct fuse_out_header oh;
 	struct fuse_copy_state cs;
-	struct fuse_conn *fc = fuse_get_conn(file);
+	struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
 	if (!fc)
 		return -EPERM;
 
@@ -670,17 +836,33 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov,
 		goto err_unlock;
 
 	req = request_find(fc, oh.unique);
-	err = -EINVAL;
 	if (!req)
 		goto err_unlock;
 
-	if (req->interrupted) {
+	if (req->aborted) {
 		spin_unlock(&fc->lock);
 		fuse_copy_finish(&cs);
 		spin_lock(&fc->lock);
 		request_end(fc, req);
 		return -ENOENT;
 	}
+	/* Is it an interrupt reply? */
+	if (req->intr_unique == oh.unique) {
+		err = -EINVAL;
+		if (nbytes != sizeof(struct fuse_out_header))
+			goto err_unlock;
+
+		if (oh.error == -ENOSYS)
+			fc->no_interrupt = 1;
+		else if (oh.error == -EAGAIN)
+			queue_interrupt(fc, req);
+
+		spin_unlock(&fc->lock);
+		fuse_copy_finish(&cs);
+		return nbytes;
+	}
+
+	req->state = FUSE_REQ_WRITING;
 	list_move(&req->list, &fc->io);
 	req->out.h = oh;
 	req->locked = 1;
@@ -693,9 +875,9 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov,
 	spin_lock(&fc->lock);
 	req->locked = 0;
 	if (!err) {
-		if (req->interrupted)
+		if (req->aborted)
 			err = -ENOENT;
-	} else if (!req->interrupted)
+	} else if (!req->aborted)
 		req->out.h.error = -EIO;
 	request_end(fc, req);
 
@@ -708,15 +890,6 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov,
 	return err;
 }
 
-static ssize_t fuse_dev_write(struct file *file, const char __user *buf,
-			      size_t nbytes, loff_t *off)
-{
-	struct iovec iov;
-	iov.iov_len = nbytes;
-	iov.iov_base = (char __user *) buf;
-	return fuse_dev_writev(file, &iov, 1, off);
-}
-
 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
 {
 	unsigned mask = POLLOUT | POLLWRNORM;
@@ -729,7 +902,7 @@ static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
 	spin_lock(&fc->lock);
 	if (!fc->connected)
 		mask = POLLERR;
-	else if (!list_empty(&fc->pending))
+	else if (request_pending(fc))
 		mask |= POLLIN | POLLRDNORM;
 	spin_unlock(&fc->lock);
 
@@ -755,7 +928,7 @@ static void end_requests(struct fuse_conn *fc, struct list_head *head)
 /*
  * Abort requests under I/O
  *
- * The requests are set to interrupted and finished, and the request
+ * The requests are set to aborted and finished, and the request
  * waiter is woken up.  This will make request_wait_answer() wait
  * until the request is unlocked and then return.
  *
@@ -770,7 +943,7 @@ static void end_io_requests(struct fuse_conn *fc)
 			list_entry(fc->io.next, struct fuse_req, list);
 		void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
 
-		req->interrupted = 1;
+		req->aborted = 1;
 		req->out.h.error = -ECONNABORTED;
 		req->state = FUSE_REQ_FINISHED;
 		list_del_init(&req->list);
@@ -803,9 +976,8 @@ static void end_io_requests(struct fuse_conn *fc)
  * onto the pending list is prevented by req->connected being false.
  *
  * Progression of requests under I/O to the processing list is
- * prevented by the req->interrupted flag being true for these
- * requests.  For this reason requests on the io list must be aborted
- * first.
+ * prevented by the req->aborted flag being true for these requests.
+ * For this reason requests on the io list must be aborted first.
  */
 void fuse_abort_conn(struct fuse_conn *fc)
 {
@@ -852,10 +1024,10 @@ static int fuse_dev_fasync(int fd, struct file *file, int on)
 const struct file_operations fuse_dev_operations = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
-	.read		= fuse_dev_read,
-	.readv		= fuse_dev_readv,
-	.write		= fuse_dev_write,
-	.writev		= fuse_dev_writev,
+	.read		= do_sync_read,
+	.aio_read	= fuse_dev_read,
+	.write		= do_sync_write,
+	.aio_write	= fuse_dev_write,
 	.poll		= fuse_dev_poll,
 	.release	= fuse_dev_release,
 	.fasync		= fuse_dev_fasync,