Messages in this thread | | | From | Jeff Moyer <> | Date | Tue, 20 Sep 2005 15:02:04 -0400 | Subject | autofs4 looks up wrong path element when ghosting is enabled |
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Hi, Ian, list,
I have a bug filed against autofs when ghosting is enabled. The best way to describe the bug is to walk through the reproducer, I guess.
Take the following maps, for example:
auto.master /sbox auto.sbox
auto.sbox: src segfault:/sbox/src/
Let's say that there is a file, id3_0.12.orig.tar.gz, in segfault:/sbox/src/.
To reproduce the problem, stop the nfs service on the server.
On the client, do an 'ls /sbox/src/id3_012.orig.tar.gz'. This will fail, as well it should. However, if we look in the logs, we find this:
automount[1182]: handle_packet_missing: token 1, name src automount[1182]: attempting to mount entry /sbox/src ... automount[1481]: mount(nfs): calling mkdir_path /sbox/src automount[1481]: mount(nfs): calling mount -t nfs -s-o tcp,intr,timeo=600,rsize=8192,wsize=8192,retrans=5 segfault:/sbox/src /sbox/src automount[1481]: >> mount: RPC: Program not registered automount[1481]: mount(nfs): add_bad_host: segfault:/sbox/src automount[1481]: mount(nfs): nfs: mount failure segfault:/sbox/src on /sbox/src automount[1481]: failed to mount /sbox/src ... automount[1182]: send_fail: token=1 automount[1182]: handle_packet: type = 0 automount[1182]: handle_packet_missing: token 2, name src/id3_0.12.orig.tar.gz automount[1182]: attempting to mount entry /sbox/src/id3_0.12.orig.tar.gz
Noteworthy are these last two lines! Even though the mount failed, we are continuing the lookup. The culprit is here, in cached_lookup:
if (!dentry->d_op->d_revalidate(dentry, flags) && !d_invalidate(dentry)) { dput(dentry); dentry = NULL; }
d_revalidate points to autofs4_revalidate, which calls try_to_fill_dentry, which will return a status of 0. Since ghosting is enabled, d_invalidate(dentry) will return -EBUSY, and so we return the dentry to the caller, which then continues the lookup.
Ian, I'm not really sure how we can address this issue without VFS changes. Any ideas?
Oh, also note that, once the nfs service is started up again on the server, the lookup of a specific file name will still fail! In this case, the daemon won't even be called.
-Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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