From 0dba36ab4e8414458889990d8423f0f29a8ae638 Mon Sep 17 00:00:00 2001
From: Francesco Mazzoli <francesco.mazzoli@xtxmarkets.com>
Date: Thu, 22 Feb 2024 18:06:30 +0000
Subject: [PATCH] ETIMEDOUT on zero response

The expected behavior is not really documented, but this seems to
be what is happening.
---
 kmod/shuckle.c | 2 ++
 kmod/super.c   | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/kmod/shuckle.c b/kmod/shuckle.c
index 138379cf..6169697e 100644
--- a/kmod/shuckle.c
+++ b/kmod/shuckle.c
@@ -110,6 +110,7 @@ int eggsfs_create_shuckle_socket(atomic64_t* addr1, atomic64_t* addr2, struct so
             iov.iov_base = resp_header + read_so_far;
             iov.iov_len = sizeof(resp_header) - read_so_far;
             int read = kernel_recvmsg(*sock, &msg, &iov, 1, iov.iov_len, 0);
+            if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
             if (read < 0) { err = read; goto out_sock; }
             read_so_far += read;
         }
@@ -127,6 +128,7 @@ int eggsfs_create_shuckle_socket(atomic64_t* addr1, atomic64_t* addr2, struct so
                 iov.iov_base = (char*)&resp + read_so_far;
                 iov.iov_len = sizeof(resp) - read_so_far;
                 int read = kernel_recvmsg(*sock, &msg, &iov, 1, iov.iov_len, 0);
+                if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
                 if (read < 0) { err = read; goto out_sock; }
                 read_so_far += read;
             }
diff --git a/kmod/super.c b/kmod/super.c
index 303c18bb..1f03f38f 100644
--- a/kmod/super.c
+++ b/kmod/super.c
@@ -57,6 +57,7 @@ static int eggsfs_refresh_fs_info(struct eggsfs_fs_info* info) {
         iov.iov_base = shards_resp_header + read_so_far;
         iov.iov_len = sizeof(shards_resp_header) - read_so_far;
         int read = kernel_recvmsg(shuckle_sock, &msg, &iov, 1, iov.iov_len, 0);
+        if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
         if (read < 0) { err = read; goto out_sock; }
         read_so_far += read;
     }
@@ -81,6 +82,7 @@ static int eggsfs_refresh_fs_info(struct eggsfs_fs_info* info) {
             iov.iov_base = shard_info_resp + read_so_far;
             iov.iov_len = sizeof(shard_info_resp) - read_so_far;
             int read = kernel_recvmsg(shuckle_sock, &msg, &iov, 1, iov.iov_len, 0);
+            if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
             if (read < 0) { err = read; goto out_sock; }
             read_so_far += read;
         }
@@ -118,6 +120,7 @@ static int eggsfs_refresh_fs_info(struct eggsfs_fs_info* info) {
         iov.iov_base = cdc_resp_header + read_so_far;
         iov.iov_len = sizeof(cdc_resp_header) - read_so_far;
         int read = kernel_recvmsg(shuckle_sock, &msg, &iov, 1, iov.iov_len, 0);
+        if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
         if (read < 0) { err = read; goto out_sock; }
         read_so_far += read;
     }
@@ -133,6 +136,7 @@ static int eggsfs_refresh_fs_info(struct eggsfs_fs_info* info) {
             iov.iov_base = (char*)&cdc_resp + read_so_far;
             iov.iov_len = sizeof(cdc_resp) - read_so_far;
             int read = kernel_recvmsg(shuckle_sock, &msg, &iov, 1, iov.iov_len, 0);
+            if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
             if (read < 0) { err = read; goto out_sock; }
             read_so_far += read;
         }
@@ -319,6 +323,7 @@ static int eggsfs_statfs(struct dentry* dentry, struct kstatfs* stats) {
         iov.iov_base = shuckle_resp_header + read_so_far;
         iov.iov_len = sizeof(shuckle_resp_header) - read_so_far;
         int read = kernel_recvmsg(shuckle_sock, &msg, &iov, 1, iov.iov_len, 0);
+        if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
         if (read < 0) {
             err = read;
             eggsfs_info("could not recv msg err=%d", err);
@@ -342,6 +347,7 @@ static int eggsfs_statfs(struct dentry* dentry, struct kstatfs* stats) {
         iov.iov_base = (char*)&shuckle_resp + read_so_far;
         iov.iov_len = sizeof(shuckle_resp) - read_so_far;
         int read = kernel_recvmsg(shuckle_sock, &msg, &iov, 1, iov.iov_len, 0);
+        if (read == 0) { err = -ETIMEDOUT; goto out_sock; }
         if (read < 0) {
             err = read;
             eggsfs_info("could not recv msg err=%d", err);