1 files changed, 34 insertions, 14 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 817e46537e3c..a5c3bc632a21 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -148,9 +148,13 @@ static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 
 static void fuse_drop_waiting(struct fuse_conn *fc)
 {
-	if (fc->connected) {
-		atomic_dec(&fc->num_waiting);
-	} else if (atomic_dec_and_test(&fc->num_waiting)) {
+	/*
+	 * lockess check of fc->connected is okay, because atomic_dec_and_test()
+	 * provides a memory barrier mached with the one in fuse_wait_aborted()
+	 * to ensure no wake-up is missed.
+	 */
+	if (atomic_dec_and_test(&fc->num_waiting) &&
+	    !READ_ONCE(fc->connected)) {
 		/* wake up aborters */
 		wake_up_all(&fc->blocked_waitq);
 	}
@@ -856,7 +860,6 @@ static int fuse_check_page(struct page *page)
 {
 	if (page_mapcount(page) ||
 	    page->mapping != NULL ||
-	    page_count(page) != 1 ||
 	    (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 	     ~(1 << PG_locked |
 	       1 << PG_referenced |
@@ -934,6 +937,13 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 	if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 		lru_cache_add_file(newpage);
 
+	/*
+	 * Release while we have extra ref on stolen page.  Otherwise
+	 * anon_pipe_buf_release() might think the page can be reused.
+	 */
+	buf->ops->release(cs->pipe, buf);
+	buf->ops = NULL;
+
 	err = 0;
 	spin_lock(&cs->req->waitq.lock);
 	if (test_bit(FR_ABORTED, &cs->req->flags))
@@ -1322,6 +1332,15 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
 		goto restart;
 	}
 	spin_lock(&fpq->lock);
+	/*
+	 *  Must not put request on fpq->io queue after having been shut down by
+	 *  fuse_abort_conn()
+	 */
+	if (!fpq->connected) {
+		req->out.h.error = err = -ECONNABORTED;
+		goto out_end;
+
+	}
 	list_add(&req->list, &fpq->io);
 	spin_unlock(&fpq->lock);
 	cs->req = req;
@@ -1422,7 +1441,6 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 		goto out;
 
 	ret = 0;
-	pipe_lock(pipe);
 
 	if (!pipe->readers) {
 		send_sig(SIGPIPE, current, 0);
@@ -1458,7 +1476,6 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 	}
 
 out_unlock:
-	pipe_unlock(pipe);
 
 	if (do_wakeup) {
 		smp_mb();
@@ -1929,7 +1946,7 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
 	}
 
 	err = -EINVAL;
-	if (oh.error <= -1000 || oh.error > 0)
+	if (oh.error <= -512 || oh.error > 0)
 		goto err_finish;
 
 	spin_lock(&fpq->lock);
@@ -2048,10 +2065,8 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 		rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
 
 	ret = -EINVAL;
-	if (rem < len) {
-		pipe_unlock(pipe);
-		goto out;
-	}
+	if (rem < len)
+		goto out_free;
 
 	rem = len;
 	while (rem) {
@@ -2069,7 +2084,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 			pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
 			pipe->nrbufs--;
 		} else {
-			ibuf->ops->get(pipe, ibuf);
+			if (!pipe_buf_get(pipe, ibuf))
+				goto out_free;
+
 			*obuf = *ibuf;
 			obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
 			obuf->len = rem;
@@ -2092,13 +2109,14 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 	ret = fuse_dev_do_write(fud, &cs, len);
 
 	pipe_lock(pipe);
+out_free:
 	for (idx = 0; idx < nbuf; idx++) {
 		struct pipe_buffer *buf = &bufs[idx];
-		buf->ops->release(pipe, buf);
+		if (buf->ops)
+			buf->ops->release(pipe, buf);
 	}
 	pipe_unlock(pipe);
 
-out:
 	kfree(bufs);
 	return ret;
 }
@@ -2239,6 +2257,8 @@ EXPORT_SYMBOL_GPL(fuse_abort_conn);
 
 void fuse_wait_aborted(struct fuse_conn *fc)
 {
+	/* matches implicit memory barrier in fuse_drop_waiting() */
+	smp_mb();
 	wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
 }