1 files changed, 76 insertions, 32 deletions

diff --git a/fs/bcachefs/thread_with_file.c b/fs/bcachefs/thread_with_file.c
index 940db15d6a93..314a24d15d4e 100644
--- a/fs/bcachefs/thread_with_file.c
+++ b/fs/bcachefs/thread_with_file.c
@@ -67,9 +67,14 @@ err:
 
 /* stdio_redirect */
 
+static bool stdio_redirect_has_more_input(struct stdio_redirect *stdio, size_t seen)
+{
+	return stdio->input.buf.nr > seen || stdio->done;
+}
+
 static bool stdio_redirect_has_input(struct stdio_redirect *stdio)
 {
-	return stdio->input.buf.nr || stdio->done;
+	return stdio_redirect_has_more_input(stdio, 0);
 }
 
 static bool stdio_redirect_has_output(struct stdio_redirect *stdio)
@@ -181,9 +186,13 @@ static ssize_t thread_with_stdio_write(struct file *file, const char __user *ubu
 		}
 
 		spin_lock(&buf->lock);
-		if (buf->buf.nr < STDIO_REDIRECT_BUFSIZE)
-			darray_make_room_gfp(&buf->buf,
-				min(b, STDIO_REDIRECT_BUFSIZE - buf->buf.nr), GFP_NOWAIT);
+		size_t makeroom = b;
+		if (!buf->waiting_for_line || memchr(buf->buf.data, '\n', buf->buf.nr))
+			makeroom = min_t(ssize_t, makeroom,
+				   max_t(ssize_t, STDIO_REDIRECT_BUFSIZE - buf->buf.nr,
+						  0));
+		darray_make_room_gfp(&buf->buf, makeroom, GFP_NOWAIT);
+
 		b = min(len, darray_room(buf->buf));
 
 		if (b && !copy_from_user_nofault(&darray_top(buf->buf), ubuf, b)) {
@@ -266,7 +275,6 @@ static long thread_with_stdio_ioctl(struct file *file, unsigned int cmd, unsigne
 }
 
 static const struct file_operations thread_with_stdio_fops = {
-	.llseek		= no_llseek,
 	.read		= thread_with_stdio_read,
 	.write		= thread_with_stdio_write,
 	.poll		= thread_with_stdio_poll,
@@ -276,7 +284,6 @@ static const struct file_operations thread_with_stdio_fops = {
 };
 
 static const struct file_operations thread_with_stdout_fops = {
-	.llseek		= no_llseek,
 	.read		= thread_with_stdio_read,
 	.poll		= thread_with_stdout_poll,
 	.flush		= thread_with_stdio_flush,
@@ -294,16 +301,27 @@ static int thread_with_stdio_fn(void *arg)
 	return 0;
 }
 
-int bch2_run_thread_with_stdio(struct thread_with_stdio *thr,
-			       const struct thread_with_stdio_ops *ops)
+void bch2_thread_with_stdio_init(struct thread_with_stdio *thr,
+				 const struct thread_with_stdio_ops *ops)
 {
 	stdio_buf_init(&thr->stdio.input);
 	stdio_buf_init(&thr->stdio.output);
 	thr->ops = ops;
+}
 
+int __bch2_run_thread_with_stdio(struct thread_with_stdio *thr)
+{
 	return bch2_run_thread_with_file(&thr->thr, &thread_with_stdio_fops, thread_with_stdio_fn);
 }
 
+int bch2_run_thread_with_stdio(struct thread_with_stdio *thr,
+			       const struct thread_with_stdio_ops *ops)
+{
+	bch2_thread_with_stdio_init(thr, ops);
+
+	return __bch2_run_thread_with_stdio(thr);
+}
+
 int bch2_run_thread_with_stdout(struct thread_with_stdio *thr,
 				const struct thread_with_stdio_ops *ops)
 {
@@ -344,43 +362,67 @@ int bch2_stdio_redirect_read(struct stdio_redirect *stdio, char *ubuf, size_t le
 	return ret;
 }
 
-int bch2_stdio_redirect_readline(struct stdio_redirect *stdio, char *ubuf, size_t len)
+int bch2_stdio_redirect_readline_timeout(struct stdio_redirect *stdio,
+					 darray_char *line,
+					 unsigned long timeout)
 {
+	unsigned long until = jiffies + timeout, t;
 	struct stdio_buf *buf = &stdio->input;
-	size_t copied = 0;
-	ssize_t ret = 0;
+	size_t seen = 0;
 again:
-	do {
-		wait_event_timeout(buf->wait, stdio_redirect_has_input(stdio),
-				   sysctl_hung_task_timeout_secs * HZ / 2);
-	} while (!stdio_redirect_has_input(stdio));
+	t = timeout != MAX_SCHEDULE_TIMEOUT
+		? max_t(long, until - jiffies, 0)
+		: timeout;
 
-	if (stdio->done) {
-		ret = -1;
-		goto out;
-	}
+	t = min(t, sysctl_hung_task_timeout_secs * HZ / 2);
+
+	wait_event_timeout(buf->wait, stdio_redirect_has_more_input(stdio, seen), t);
+
+	if (stdio->done)
+		return -1;
 
 	spin_lock(&buf->lock);
-	size_t b = min(len, buf->buf.nr);
-	char *n = memchr(buf->buf.data, '\n', b);
-	if (n)
-		b = min_t(size_t, b, n + 1 - buf->buf.data);
+	seen = buf->buf.nr;
+	char *n = memchr(buf->buf.data, '\n', seen);
+
+	if (!n && timeout != MAX_SCHEDULE_TIMEOUT && time_after_eq(jiffies, until)) {
+		spin_unlock(&buf->lock);
+		return -ETIME;
+	}
+
+	if (!n) {
+		buf->waiting_for_line = true;
+		spin_unlock(&buf->lock);
+		goto again;
+	}
+
+	size_t b = n + 1 - buf->buf.data;
+	if (b > line->size) {
+		spin_unlock(&buf->lock);
+		int ret = darray_resize(line, b);
+		if (ret)
+			return ret;
+		seen = 0;
+		goto again;
+	}
+
 	buf->buf.nr -= b;
-	memcpy(ubuf, buf->buf.data, b);
+	memcpy(line->data, buf->buf.data, b);
 	memmove(buf->buf.data,
 		buf->buf.data + b,
 		buf->buf.nr);
-	ubuf += b;
-	len -= b;
-	copied += b;
+	line->nr = b;
+
+	buf->waiting_for_line = false;
 	spin_unlock(&buf->lock);
 
 	wake_up(&buf->wait);
+	return 0;
+}
 
-	if (!n && len)
-		goto again;
-out:
-	return copied ?: ret;
+int bch2_stdio_redirect_readline(struct stdio_redirect *stdio, darray_char *line)
+{
+	return bch2_stdio_redirect_readline_timeout(stdio, line, MAX_SCHEDULE_TIMEOUT);
 }
 
 __printf(3, 0)
@@ -413,8 +455,10 @@ ssize_t bch2_stdio_redirect_vprintf(struct stdio_redirect *stdio, bool nonblocki
 	struct stdio_buf *buf = &stdio->output;
 	unsigned long flags;
 	ssize_t ret;
-
 again:
+	if (stdio->done)
+		return -EPIPE;
+
 	spin_lock_irqsave(&buf->lock, flags);
 	ret = bch2_darray_vprintf(&buf->buf, GFP_NOWAIT, fmt, args);
 	spin_unlock_irqrestore(&buf->lock, flags);