Hi Xiang,
I'm not entirely clear on what does the disconnect variable solves.
Disconnection could occur at any point during the execution of loop_fn,
meaning any read/write operations on the socket performed by loop_fn
might return EPIPE, and we must handle this case appropriately,
and I think merely checking whether disconnection has occurred
at fixed points in the loop is insufficient?
Thanks,
Yifan
On 12/27/2025 8:40 PM, Gao Xiang wrote:
Hi Yifan,
On 2025/12/27 19:39, Yifan Zhao wrote:
Currently erofsmount_startnbd() doesn't ignore SIGPIPE, causing
erofsmount_nbd_loopfn() to be killed abruptly without clean up during
disconnect. Moreover, -EPIPE from NBD socket I/O is expected while
disconnecting, and erofsmount_startnbd() treats it as error, leading to
redundant print:
```
<E> erofs: NBD worker failed with [Error 32] Broken pipe
```
Signed-off-by: Yifan Zhao <[email protected]>
---
mount/main.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/mount/main.c b/mount/main.c
index 5ba2e0a..965b0b8 100644
--- a/mount/main.c
+++ b/mount/main.c
@@ -621,11 +621,8 @@ static void *erofsmount_nbd_loopfn(void *arg)
off_t pos;
err = erofs_nbd_get_request(ctx->sk.fd, &rq);
- if (err < 0) {
- if (err == -EPIPE)
- err = 0;
+ if (err < 0)
break;
- }
if (rq.type != EROFS_NBD_CMD_READ) {
err = erofs_nbd_send_reply_header(ctx->sk.fd,
@@ -653,6 +650,8 @@ static void *erofsmount_nbd_loopfn(void *arg)
out:
erofs_io_close(&ctx->vd);
erofs_io_close(&ctx->sk);
+ if (err == -EPIPE)
+ err = 0;
return (void *)(uintptr_t)err;
}
@@ -663,6 +662,12 @@ static int erofsmount_startnbd(int nbdfd,
struct erofs_nbd_source *source)
pthread_t th;
int err, err2;
+ /* Otherwise, NBD disconnect sends SIGPIPE, skipping cleanup */
+ if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
+ err = -errno;
+ goto out_closefd;
+ }
Can we register a signal handler for SIGPIPE instead, and setup
a disconnected variable for erofsmount_nbd_loopfn() to notice
for example too (in case of unnecessary erofs_nbd_get_request()).
Thanks,
Gao Xiang
+
if (source->type == EROFSNBD_SOURCE_OCI) {
if (source->ocicfg.tarindex_path ||
source->ocicfg.zinfo_path) {
err = erofsmount_tarindex_open(&ctx.vd, &source->ocicfg,
