On 22.05.2012 19:00, Myklebust, Trond wrote:
On Tue, 2012-05-22 at 10:29 -0400, Trond Myklebust wrote:
On Tue, 2012-05-22 at 16:40 +0400, Stanislav Kinsbursky wrote:
Client have to be initialized prior to adding it to per-net clients list,
because otherwise there are races, shown below:
CPU#0 CPU#1
_____ _____
nfs_get_client
nfs_alloc_client
list_add(..., nfs_client_list)
rpc_fill_super
rpc_pipefs_event
nfs_get_client_for_event
__rpc_pipefs_event
(clp->cl_rpcclient is uninitialized)
BUG()
init_client
clp->cl_rpcclient = ...
Why not simply change nfs_get_client_for_event() so that it doesn't
touch nfs_clients that have clp->cl_cons_state!=NFS_CS_READY?
That should ensure that it doesn't touch nfs_clients that failed to
initialise and/or are still in the process of being initialised.
...actually, come to think of it. Why not just add a helper function
"bool nfs_client_active(const struct nfs_client *clp)" to
fs/nfs/client.c that does a call to
wait_event_killable(nfs_client_active_wq, clp->cl_cons_state< NFS_CS_INITING);
and checks the resulting value of clp->cl_cons_state?
Sorry, but I don't understand the idea...
Where are you proposing to call this function?
In __rpc_pipefs_event() prior to dentries creatios?
--
Best regards,
Stanislav Kinsbursky
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