Sorry, replied too early. :)
On 01.04.25 16:35, Eric Blake wrote:
On Tue, Mar 25, 2025 at 05:06:51PM +0100, Hanna Czenczek wrote:
Manually read requests from the /dev/fuse FD and process them, without
using libfuse. This allows us to safely add parallel request processing
in coroutines later, without having to worry about libfuse internals.
(Technically, we already have exactly that problem with
read_from_fuse_export()/read_from_fuse_fd() nesting.)
We will continue to use libfuse for mounting the filesystem; fusermount3
is a effectively a helper program of libfuse, so it should know best how
to interact with it. (Doing it manually without libfuse, while doable,
is a bit of a pain, and it is not clear to me how stable the "protocol"
actually is.)
@@ -247,6 +268,14 @@ static int fuse_export_create(BlockExport *blk_exp,
g_hash_table_insert(exports, g_strdup(exp->mountpoint), NULL);
+ exp->fuse_fd = fuse_session_fd(exp->fuse_session);
+ ret = fcntl(exp->fuse_fd, F_SETFL, O_NONBLOCK);
fctnl(F_SETFL) should be used in a read-modify-write pattern with
F_GETFL (otherwise, you are nuking any other flags that might have
been important).
See also block/file-posix.c:fcntl_setfl. Maybe we should hoist that
into a common helper in util/osdep.c?
Sounds good.
/**
- * Handle client reads from the exported image.
+ * Handle client reads from the exported image. Allocates *bufptr and reads
+ * data from the block device into that buffer.
Worth calling out tht *bufptr must be freed with qemu_vfree...
Yep, I’ll add it.
Hanna
