[PATCH] nfs: fix congestion control

The current NFS client congestion logic is severly broken, it marks the
backing device congested during each nfs_writepages() call but doesn't
mirror this in nfs_writepage() which makes for deadlocks.  Also it
implements its own waitqueue.

Replace this by a more regular congestion implementation that puts a cap on
the number of active writeback pages and uses the bdi congestion waitqueue.

Also always use an interruptible wait since it makes sense to be able to
SIGKILL the process even for mounts without 'intr'.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index bb516a2cfba..f1eae44b9a1 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -151,10 +151,10 @@ int __init register_nfs_fs(void)
         if (ret < 0)
                 goto error_0;
 
-#ifdef CONFIG_NFS_V4
         ret = nfs_register_sysctl();
         if (ret < 0)
                 goto error_1;
+#ifdef CONFIG_NFS_V4
         ret = register_filesystem(&nfs4_fs_type);
         if (ret < 0)
                 goto error_2;
@@ -165,9 +165,9 @@ int __init register_nfs_fs(void)
 #ifdef CONFIG_NFS_V4
 error_2:
         nfs_unregister_sysctl();
+#endif
 error_1:
         unregister_filesystem(&nfs_fs_type);
-#endif
 error_0:
         return ret;
 }