On 06/18/2012 09:28 AM, Myklebust, Trond wrote:
> On Mon, 2012-06-18 at 11:04 +0200, Andre Tomt wrote:
>> On 16. juni 2012 21:59, Myklebust, Trond wrote:
>>> It looks to me as if the legacy upcall code is assuming that there can
>>> be no more than 1 upcall at a time: there is only a single
>>> idmap->idmap_key_cons, which gets assigned in nfs_idmap_legacy_upcall
>>> and then read in idmap_pipe_downcall.
>>>
>>> Bryan, can you look into this? I suspect that we need a mutex or
>>> something like that (for the legacy upcall case only) to ensure that
>>> nobody overwrites the idmap->idmap_key_cons while an upcall is in
>>> progress.
>>>
>>> Andre, if you want idmapper scalability, then you should rather use the
>>> new idmapper upcall. You need a recent version of the nfs-utils package,
>>> the keyutils package, and they you should add an 'id_resolver' line
>>> to /etc/request-keys.conf as per the nfsidmap manpage.
>>
>> Indeed, using keyutils did avoid the crashes here, 40 hours and counting.
>>
>> Are there any downsides of having keyutils w/ id_resolver on by default
>> in a distribution? Would it break older kernels or nfs-utils (just not
>> getting used is fine, obviously)?
>
> Older kernels aren't able to use the keyutils mechanism, so they will
> still require you to run the idmapd daemon, but there should be no
> problems with just enabling it in /etc/request-key.conf.
> Fedora 17 is supposed to install the id_resolver by default.
>
Hi Andre,
Can you please check if this patch fixes the old idmapper?
- Bryan
>From 3bef58765c7308965d06d9e9d7707c7ca55648ee Mon Sep 17 00:00:00 2001
From: Bryan Schumaker <bjschuma@xxxxxxxxxx>
Date: Mon, 18 Jun 2012 12:01:25 -0400
Subject: [PATCH] NFS: Force the legacy idmapper to be single threaded
It was initially coded under the assumption that there would only be one
request at a time, so use a lock to enforce this requirement..
Signed-off-by: Bryan Schumaker <bjschuma@xxxxxxxxxx>
---
fs/nfs/idmap.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index b5b86a0..864c51e 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -57,6 +57,11 @@ unsigned int nfs_idmap_cache_timeout = 600;
static const struct cred *id_resolver_cache;
static struct key_type key_type_id_resolver_legacy;
+struct idmap {
+ struct rpc_pipe *idmap_pipe;
+ struct key_construction *idmap_key_cons;
+ struct mutex idmap_mutex;
+};
/**
* nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
@@ -310,9 +315,11 @@ static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
name, namelen, type, data,
data_size, NULL);
if (ret < 0) {
+ mutex_lock(&idmap->idmap_mutex);
ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
name, namelen, type, data,
data_size, idmap);
+ mutex_unlock(&idmap->idmap_mutex);
}
return ret;
}
@@ -354,11 +361,6 @@ static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *typ
/* idmap classic begins here */
module_param(nfs_idmap_cache_timeout, int, 0644);
-struct idmap {
- struct rpc_pipe *idmap_pipe;
- struct key_construction *idmap_key_cons;
-};
-
enum {
Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
};
@@ -469,6 +471,7 @@ nfs_idmap_new(struct nfs_client *clp)
return error;
}
idmap->idmap_pipe = pipe;
+ mutex_init(&idmap->idmap_mutex);
clp->cl_idmap = idmap;
return 0;
--
1.7.10.4
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