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From:   Daniil Lunev <dlunev@chromium.org>
To:     linux-fsdevel@vger.kernel.org, miklos@szeredi.hu,
        viro@zeniv.linux.org.uk, hch@infradead.org, tytso@mit.edu
Cc:     linux-kernel@vger.kernel.org, fuse-devel@lists.sourceforge.net,
        Daniil Lunev <dlunev@chromium.org>,
        Daniil Lunev <dlunev@google.com>
Subject: [PATCH v4 2/2] FUSE: Retire superblock on force unmount
Date:   Wed,  1 Jun 2022 11:11:03 +1000
Message-Id: <20220601111059.v4.2.I692165059274c30b59bed56940b54a573ccb46e4@changeid>
In-Reply-To: <20220601011103.12681-1-dlunev@google.com>
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From: Daniil Lunev <dlunev@chromium.org>

Force unmount of FUSE severes the connection with the user space, even
if there are still open files. Subsequent remount tries to re-use the
superblock held by the open files, which is meaningless in the FUSE case
after disconnect - reused super block doesn't have userspace counterpart
attached to it and is incapable of doing any IO.

Signed-off-by: Daniil Lunev <dlunev@chromium.org>

Signed-off-by: Daniil Lunev <dlunev@google.com>
---

(no changes since v3)

Changes in v3:
- No changes

Changes in v2:
- Use an exported function instead of directly modifying superblock

 fs/fuse/inode.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 8c0665c5dff88..8875361544b2a 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -476,8 +476,11 @@ static void fuse_umount_begin(struct super_block *sb)
 {
 	struct fuse_conn *fc = get_fuse_conn_super(sb);
 
-	if (!fc->no_force_umount)
-		fuse_abort_conn(fc);
+	if (fc->no_force_umount)
+		return;
+
+	fuse_abort_conn(fc);
+	retire_super(sb);
 }
 
 static void fuse_send_destroy(struct fuse_mount *fm)
-- 
2.31.0