From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: viro@zeniv.linux.org.uk
Cc: autofs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [RFC] Don't propagate automount
Date: Thu, 26 Sep 2019 14:52:34 -0500 [thread overview]
Message-ID: <20190926195234.bipqpw5sbk5ojcna@fiona> (raw)
An access to automounted filesystem can deadlock if it is a bind
mount on shared mounts. A user program should not deadlock the kernel
while automount waits for propagation of the mount. This is explained
at https://bugzilla.redhat.com/show_bug.cgi?id=1358887#c10
I am not sure completely blocking automount is the best solution,
so please reply with what is the best course of action to do
in such a situation.
Propagation of dentry with DCACHE_NEED_AUTOMOUNT can lead to
propagation of mount points without automount maps and not under
automount control. So, do not propagate them.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
diff --git a/fs/pnode.c b/fs/pnode.c
index 49f6d7ff2139..b960805d7954 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -292,6 +292,9 @@ int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
struct mount *m, *n;
int ret = 0;
+ if (source_mnt->mnt_mountpoint->d_flags & DCACHE_NEED_AUTOMOUNT)
+ return 0;
+
/*
* we don't want to bother passing tons of arguments to
* propagate_one(); everything is serialized by namespace_sem,
--
Goldwyn
next reply other threads:[~2019-09-26 19:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 19:52 Goldwyn Rodrigues [this message]
2019-09-27 1:35 ` [RFC] Don't propagate automount Ian Kent
2019-09-27 7:09 ` Ian Kent
2019-09-27 7:26 ` Ian Kent
2019-09-27 7:41 ` Ian Kent
2019-09-27 10:51 ` Ian Kent
2019-09-27 16:16 ` Goldwyn Rodrigues
2019-09-28 1:47 ` Ian Kent
2019-10-01 19:09 ` Goldwyn Rodrigues
2019-10-02 2:14 ` Ian Kent
2019-10-28 16:28 ` Goldwyn Rodrigues
2019-10-28 23:57 ` Ian Kent
2019-10-29 6:39 ` Ian Kent
2019-10-29 6:40 ` Ian Kent
2019-10-29 16:00 ` Goldwyn Rodrigues
2019-10-30 6:01 ` Ian Kent
2019-10-30 6:05 ` Ian Kent
2019-10-30 12:05 ` Ian Kent
2019-10-30 19:28 ` Goldwyn Rodrigues
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