From c72bf915ae25c9f785be318bfe4aab8468bfed8e Mon Sep 17 00:00:00 2001
From: Chris Kirby <ckirby@versity.com>
Date: Fri, 3 Oct 2025 14:01:39 -0500
Subject: [PATCH] Use ENOLINK as a special error code during forced unmount

Tests such as quorum-heartbeat-timeout were failing with EIO messages in
dmesg output due to expected errors during forced unmount. Use ENOLINK
instead, and filter all errors from dmesg with this errno (67).

Signed-off-by: Chris Kirby <ckirby@versity.com>
---
 kmod/src/block.c      | 4 ++--
 kmod/src/format.h     | 3 ++-
 kmod/src/net.c        | 2 +-
 kmod/src/server.c     | 2 +-
 kmod/src/trans.c      | 4 ++--
 tests/funcs/filter.sh | 3 +++
 6 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/kmod/src/block.c b/kmod/src/block.c
index e44a98a7..0fa35dcc 100644
--- a/kmod/src/block.c
+++ b/kmod/src/block.c
@@ -488,7 +488,7 @@ static int block_submit_bio(struct super_block *sb, struct block_private *bp,
 	int ret = 0;
 
 	if (scoutfs_forcing_unmount(sb))
-		return -EIO;
+		return -ENOLINK;
 
 	sector = bp->bl.blkno << (SCOUTFS_BLOCK_LG_SHIFT - 9);
 
@@ -1210,7 +1210,7 @@ static int sm_block_io(struct super_block *sb, struct block_device *bdev, blk_op
 	BUILD_BUG_ON(PAGE_SIZE < SCOUTFS_BLOCK_SM_SIZE);
 
 	if (scoutfs_forcing_unmount(sb))
-		return -EIO;
+		return -ENOLINK;
 
 	if (WARN_ON_ONCE(len > SCOUTFS_BLOCK_SM_SIZE) ||
 	    WARN_ON_ONCE(!op_is_write(opf) && !blk_crc))
diff --git a/kmod/src/format.h b/kmod/src/format.h
index 4eab7a7b..07bb67aa 100644
--- a/kmod/src/format.h
+++ b/kmod/src/format.h
@@ -1091,7 +1091,8 @@ enum scoutfs_net_cmd {
 	EXPAND_NET_ERRNO(ENOMEM)	\
 	EXPAND_NET_ERRNO(EIO)		\
 	EXPAND_NET_ERRNO(ENOSPC)	\
-	EXPAND_NET_ERRNO(EINVAL)
+	EXPAND_NET_ERRNO(EINVAL)	\
+	EXPAND_NET_ERRNO(ENOLINK)
 
 #undef EXPAND_NET_ERRNO
 #define EXPAND_NET_ERRNO(which) SCOUTFS_NET_ERR_##which,
diff --git a/kmod/src/net.c b/kmod/src/net.c
index 613cf169..8636452e 100644
--- a/kmod/src/net.c
+++ b/kmod/src/net.c
@@ -332,7 +332,7 @@ static int submit_send(struct super_block *sb,
 		return -EINVAL;
 
 	if (scoutfs_forcing_unmount(sb))
-		return -EIO;
+		return -ENOLINK;
 
 	msend = kmalloc(offsetof(struct message_send,
 				 nh.data[data_len]), GFP_NOFS);
diff --git a/kmod/src/server.c b/kmod/src/server.c
index 9dbd1509..cd978d27 100644
--- a/kmod/src/server.c
+++ b/kmod/src/server.c
@@ -610,7 +610,7 @@ static void scoutfs_server_commit_func(struct work_struct *work)
 		goto out;
 
 	if (scoutfs_forcing_unmount(sb)) {
-		ret = -EIO;
+		ret = -ENOLINK;
 		goto out;
 	}
 
diff --git a/kmod/src/trans.c b/kmod/src/trans.c
index 10494c43..d131bfa1 100644
--- a/kmod/src/trans.c
+++ b/kmod/src/trans.c
@@ -196,7 +196,7 @@ static int retry_forever(struct super_block *sb, int (*func)(struct super_block
 			}
 
 			if (scoutfs_forcing_unmount(sb)) {
-				ret = -EIO;
+				ret = -ENOLINK;
 				break;
 			}
 
@@ -252,7 +252,7 @@ void scoutfs_trans_write_func(struct work_struct *work)
 	}
 
 	if (scoutfs_forcing_unmount(sb)) {
-		ret = -EIO;
+		ret = -ENOLINK;
 		goto out;
 	}
 
diff --git a/tests/funcs/filter.sh b/tests/funcs/filter.sh
index 294f9c72..b5a1a3cf 100644
--- a/tests/funcs/filter.sh
+++ b/tests/funcs/filter.sh
@@ -140,6 +140,9 @@ t_filter_dmesg()
 	re="$re|scoutfs .* error.*server failed to bind to.*"
 	re="$re|scoutfs .* critical transaction commit failure.*"
 
+	# ENOLINK (-67) indicates an expected forced unmount error
+	re="$re|scoutfs .* error -67 .*"
+
 	# change-devices causes loop device resizing
 	re="$re|loop: module loaded"
 	re="$re|loop[0-9].* detected capacity change from.*"