From ef818a28fac9bd214e676986d8301db0582b92a9 Mon Sep 17 00:00:00 2001
From: Steve Dickson <SteveD@redhat.com>
Date: Thu, 8 Nov 2007 04:05:04 -0500
Subject: [PATCH] NFS: Stop sillyname renames and unmounts from racing
Added an active/deactive mechanism to the nfs_server structure
allowing async operations to hold off umount until the
operations are done.
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/nfs/client.c | 3 +++
fs/nfs/internal.h | 2 ++
fs/nfs/super.c | 24 ++++++++++++++++++++++++
fs/nfs/unlink.c | 4 ++++
include/linux/nfs_fs_sb.h | 6 ++++++
5 files changed, 39 insertions(+)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index a6f625497612..c3740f5ab978 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -729,6 +729,9 @@ static struct nfs_server *nfs_alloc_server(void)
INIT_LIST_HEAD(&server->client_link);
INIT_LIST_HEAD(&server->master_link);
+ init_waitqueue_head(&server->active_wq);
+ atomic_set(&server->active, 0);
+
server->io_stats = nfs_alloc_iostats();
if (!server->io_stats) {
kfree(server);
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index f3acf48412be..75793794aefe 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -160,6 +160,8 @@ extern struct rpc_stat nfs_rpcstat;
extern int __init register_nfs_fs(void);
extern void __exit unregister_nfs_fs(void);
+extern void nfs_sb_active(struct nfs_server *server);
+extern void nfs_sb_deactive(struct nfs_server *server);
/* namespace.c */
extern char *nfs_path(const char *base,
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 0b0c72a072ff..fda1635dd133 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -202,6 +202,7 @@ static int nfs_get_sb(struct file_system_type *, int, const char *, void *, stru
static int nfs_xdev_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
static void nfs_kill_super(struct super_block *);
+static void nfs_put_super(struct super_block *);
static struct file_system_type nfs_fs_type = {
.owner = THIS_MODULE,
@@ -223,6 +224,7 @@ static const struct super_operations nfs_sops = {
.alloc_inode = nfs_alloc_inode,
.destroy_inode = nfs_destroy_inode,
.write_inode = nfs_write_inode,
+ .put_super = nfs_put_super,
.statfs = nfs_statfs,
.clear_inode = nfs_clear_inode,
.umount_begin = nfs_umount_begin,
@@ -325,6 +327,28 @@ void __exit unregister_nfs_fs(void)
unregister_filesystem(&nfs_fs_type);
}
+void nfs_sb_active(struct nfs_server *server)
+{
+ atomic_inc(&server->active);
+}
+
+void nfs_sb_deactive(struct nfs_server *server)
+{
+ if (atomic_dec_and_test(&server->active))
+ wake_up(&server->active_wq);
+}
+
+static void nfs_put_super(struct super_block *sb)
+{
+ struct nfs_server *server = NFS_SB(sb);
+ /*
+ * Make sure there are no outstanding ops to this server.
+ * If so, wait for them to finish before allowing the
+ * unmount to continue.
+ */
+ wait_event(server->active_wq, atomic_read(&server->active) == 0);
+}
+
/*
* Deliver file system statistics to userspace
*/
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 431981d0265f..8e5428e0b86f 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -14,6 +14,8 @@
#include <linux/sched.h>
#include <linux/wait.h>
+#include "internal.h"
+
struct nfs_unlinkdata {
struct hlist_node list;
struct nfs_removeargs args;
@@ -113,6 +115,7 @@ static void nfs_async_unlink_release(void *calldata)
struct nfs_unlinkdata *data = calldata;
nfs_dec_sillycount(data->dir);
+ nfs_sb_deactive(NFS_SERVER(data->dir));
nfs_free_unlinkdata(data);
}
@@ -153,6 +156,7 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
nfs_dec_sillycount(dir);
return 0;
}
+ nfs_sb_active(NFS_SERVER(dir));
data->args.fh = NFS_FH(dir);
nfs_fattr_init(&data->res.dir_attr);
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 0cac49bc0955..9f949b587684 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -3,6 +3,9 @@
#include <linux/list.h>
#include <linux/backing-dev.h>
+#include <linux/wait.h>
+
+#include <asm/atomic.h>
struct nfs_iostats;
@@ -110,6 +113,9 @@ struct nfs_server {
filesystem */
#endif
void (*destroy)(struct nfs_server *);
+
+ atomic_t active; /* Keep trace of any activity to this server */
+ wait_queue_head_t active_wq; /* Wait for any activity to stop */
};
/* Server capabilities */
--
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