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bcachefs: thread_with_stdio: fix bch2_stdio_redirect_readline()

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This fixes a bug where we'd return data without waiting for a newline,
if data was present but a newline was not.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-02-04 22:56:16 -05:00
parent a6777ca4ff
commit f704f108af
1 changed files with 22 additions and 11 deletions
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33
fs/bcachefs/thread_with_file.c
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@ -277,25 +277,36 @@ int bch2_stdio_redirect_read(struct stdio_redirect *stdio, char *ubuf, size_t le
int bch2_stdio_redirect_readline(struct stdio_redirect *stdio, char *ubuf, size_t len)
{
struct stdio_buf *buf = &stdio->input;
size_t copied = 0;
ssize_t ret = 0;
again:
wait_event(buf->wait, stdio_redirect_has_input(stdio));
if (stdio->done)
return -1;
if (stdio->done) {
ret = -1;
goto out;
}
spin_lock(&buf->lock);
int ret = min(len, buf->buf.nr);
char *n = memchr(buf->buf.data, '\n', ret);
if (!n)
ret = min(ret, n + 1 - buf->buf.data);
buf->buf.nr -= ret;
memcpy(ubuf, buf->buf.data, ret);
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);
buf->buf.nr -= b;
memcpy(ubuf, buf->buf.data, b);
memmove(buf->buf.data,
buf->buf.data + ret,
buf->buf.data + b,
buf->buf.nr);
ubuf += b;
len -= b;
copied += b;
spin_unlock(&buf->lock);
wake_up(&buf->wait);
return ret;
if (!n && len)
goto again;
out:
return copied ?: ret;
}
__printf(3, 0)