From 20eead18130fd460d8e9eff50ce14afd3646faab Mon Sep 17 00:00:00 2001 From: wm4 Date: Sun, 16 Feb 2020 23:36:05 +0100 Subject: stream_file: use fstat() instead of lseek() to determine file size It appears using lseek() to seek to the end and back to determine file size is inefficient in some cases. With CIFS, this restores the performance regression that happened when the stream cache was removed (which called read() from a thread). This is probably faster than the old code too, because it's the seeking that was slowing down CIFS. According to the user who tested this, the size caching does not help with fstat() (although it did with the old method). Fixes: #7408, #7152 --- stream/stream_file.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/stream/stream_file.c b/stream/stream_file.c index 6e69f33c94..9f83b73dd1 100644 --- a/stream/stream_file.c +++ b/stream/stream_file.c @@ -77,9 +77,14 @@ static int64_t get_size(stream_t *s) { struct priv *p = s->priv; if (p->cached_size == -2) { - off_t size = lseek(p->fd, 0, SEEK_END); - lseek(p->fd, s->pos, SEEK_SET); - p->cached_size = size < 0 ? -1 : size; + int64_t size = -1; + struct stat st; + if (fstat(p->fd, &st) == 0) { + if (st.st_size <= 0 && !s->seekable) + st.st_size = -1; + size = st.st_size < 0 ? -1 : st.st_size; + } + p->cached_size = size; } return p->cached_size; } -- cgit v1.2.3