>>>>> " " == Andrew Morton <[EMAIL PROTECTED]> writes:

     > There appear to be two places where the NFS client code can
     > deadlock:

     > nfs_reqlist_init() {
     >   spin_lock(&nfs_flushd_lock);
     >   rpc_new_task->
     >     rpc_allocate->
     >       -> kmalloc(GFP_RPC) (__GFP_WAIT is true)


     > inode_remove_flushd() {
     >   spin_lock(&nfs_flushd_lock);
     >   iput(inode)->
     >     nfs_delete_inode->
     >       delete_inode->
     >         wait_on_inode
     >   truncate_inode_pages->
     >     truncate_list_pages->
     >         wait_on_page

     > The latter is most likely the problem.  Here's a patch - please
     > test.  The inode_remove_flush() change is correct.  Not so sure
     > about the nfs_reqlist_init() change.


Doh. You're quite right on both accounts. I made a small modification
to your patch for the rpc_new_task() problem (you forgot to release
the RPC task if it's not used).

Linus, please apply for 2.4.1...

Cheers,
  Trond

--- linux-2.4.0/fs/nfs/flushd.c.orig    Wed Jun 21 16:25:17 2000
+++ linux-2.4.0/fs/nfs/flushd.c Wed Jan 10 10:44:08 2001
@@ -71,18 +71,17 @@
        int                     status = 0;
 
        dprintk("NFS: writecache_init\n");
+
+       /* Create the RPC task */
+       if (!(task = rpc_new_task(server->client, NULL, RPC_TASK_ASYNC)))
+               return -ENOMEM;
+
        spin_lock(&nfs_flushd_lock);
        cache = server->rw_requests;
 
        if (cache->task)
                goto out_unlock;
 
-       /* Create the RPC task */
-       status = -ENOMEM;
-       task = rpc_new_task(server->client, NULL, RPC_TASK_ASYNC);
-       if (!task)
-               goto out_unlock;
-
        task->tk_calldata = server;
 
        cache->task = task;
@@ -99,6 +98,7 @@
        return 0;
  out_unlock:
        spin_unlock(&nfs_flushd_lock);
+       rpc_release_task(task);
        return status;
 }
 
@@ -195,7 +195,9 @@
        if (*q) {
                *q = inode->u.nfs_i.hash_next;
                NFS_FLAGS(inode) &= ~NFS_INO_FLUSH;
+               spin_unlock(&nfs_flushd_lock);
                iput(inode);
+               return;
        }
  out:
        spin_unlock(&nfs_flushd_lock);
-
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