Merge branch 'sunrpc_cache-for-2.6.32' into nfs-for-2.6.32

1 files changed, 401 insertions, 149 deletions

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index ff0c23053d2f..db7720e453c3 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -27,10 +27,12 @@
 #include <linux/net.h>
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
+#include <linux/pagemap.h>
 #include <asm/ioctls.h>
 #include <linux/sunrpc/types.h>
 #include <linux/sunrpc/cache.h>
 #include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
 
 #define  RPCDBG_FACILITY RPCDBG_CACHE
 
@@ -175,7 +177,13 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
 }
 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
 
-static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
+static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+        if (!cd->cache_upcall)
+                return -EINVAL;
+        return cd->cache_upcall(cd, h);
+}
+
 /*
  * This is the generic cache management routine for all
  * the authentication caches.
@@ -284,76 +292,11 @@ static DEFINE_SPINLOCK(cache_list_lock);
 static struct cache_detail *current_detail;
 static int current_index;
 
-static const struct file_operations cache_file_operations;
-static const struct file_operations content_file_operations;
-static const struct file_operations cache_flush_operations;
-
 static void do_cache_clean(struct work_struct *work);
 static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean);
 
-static void remove_cache_proc_entries(struct cache_detail *cd)
-{
-        if (cd->proc_ent == NULL)
-                return;
-        if (cd->flush_ent)
-                remove_proc_entry("flush", cd->proc_ent);
-        if (cd->channel_ent)
-                remove_proc_entry("channel", cd->proc_ent);
-        if (cd->content_ent)
-                remove_proc_entry("content", cd->proc_ent);
-        cd->proc_ent = NULL;
-        remove_proc_entry(cd->name, proc_net_rpc);
-}
-
-#ifdef CONFIG_PROC_FS
-static int create_cache_proc_entries(struct cache_detail *cd)
-{
-        struct proc_dir_entry *p;
-
-        cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
-        if (cd->proc_ent == NULL)
-                goto out_nomem;
-        cd->channel_ent = cd->content_ent = NULL;
-
-        p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
-                             cd->proc_ent, &cache_flush_operations, cd);
-        cd->flush_ent = p;
-        if (p == NULL)
-                goto out_nomem;
-
-        if (cd->cache_request || cd->cache_parse) {
-                p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
-                                     cd->proc_ent, &cache_file_operations, cd);
-                cd->channel_ent = p;
-                if (p == NULL)
-                        goto out_nomem;
-        }
-        if (cd->cache_show) {
-                p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
-                                cd->proc_ent, &content_file_operations, cd);
-                cd->content_ent = p;
-                if (p == NULL)
-                        goto out_nomem;
-        }
-        return 0;
-out_nomem:
-        remove_cache_proc_entries(cd);
-        return -ENOMEM;
-}
-#else /* CONFIG_PROC_FS */
-static int create_cache_proc_entries(struct cache_detail *cd)
-{
-        return 0;
-}
-#endif
-
-int cache_register(struct cache_detail *cd)
+static void sunrpc_init_cache_detail(struct cache_detail *cd)
 {
-        int ret;
-
-        ret = create_cache_proc_entries(cd);
-        if (ret)
-                return ret;
         rwlock_init(&cd->hash_lock);
         INIT_LIST_HEAD(&cd->queue);
         spin_lock(&cache_list_lock);
@@ -367,11 +310,9 @@ int cache_register(struct cache_detail *cd)
 
         /* start the cleaning process */
         schedule_delayed_work(&cache_cleaner, 0);
-        return 0;
 }
-EXPORT_SYMBOL_GPL(cache_register);
 
-void cache_unregister(struct cache_detail *cd)
+static void sunrpc_destroy_cache_detail(struct cache_detail *cd)
 {
         cache_purge(cd);
         spin_lock(&cache_list_lock);
@@ -386,7 +327,6 @@ void cache_unregister(struct cache_detail *cd)
         list_del_init(&cd->others);
         write_unlock(&cd->hash_lock);
         spin_unlock(&cache_list_lock);
-        remove_cache_proc_entries(cd);
         if (list_empty(&cache_list)) {
                 /* module must be being unloaded so its safe to kill the worker */
                 cancel_delayed_work_sync(&cache_cleaner);
@@ -395,7 +335,6 @@ void cache_unregister(struct cache_detail *cd)
 out:
         printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
 }
-EXPORT_SYMBOL_GPL(cache_unregister);
 
 /* clean cache tries to find something to clean
  * and cleans it.
@@ -687,18 +626,18 @@ struct cache_reader {
         int                     offset; /* if non-0, we have a refcnt on next request */
 };
 
-static ssize_t
-cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
+                          loff_t *ppos, struct cache_detail *cd)
 {
         struct cache_reader *rp = filp->private_data;
         struct cache_request *rq;
-        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         int err;
 
         if (count == 0)
                 return 0;
 
-        mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
+        mutex_lock(&inode->i_mutex); /* protect against multiple concurrent
                               * readers on this file */
  again:
         spin_lock(&queue_lock);
@@ -711,7 +650,7 @@ cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
         }
         if (rp->q.list.next == &cd->queue) {
                 spin_unlock(&queue_lock);
-                mutex_unlock(&queue_io_mutex);
+                mutex_unlock(&inode->i_mutex);
                 BUG_ON(rp->offset);
                 return 0;
         }
@@ -758,49 +697,90 @@ cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
         }
         if (err == -EAGAIN)
                 goto again;
-        mutex_unlock(&queue_io_mutex);
+        mutex_unlock(&inode->i_mutex);
         return err ? err :  count;
 }
 
-static char write_buf[8192]; /* protected by queue_io_mutex */
+static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
+                                 size_t count, struct cache_detail *cd)
+{
+        ssize_t ret;
+
+        if (copy_from_user(kaddr, buf, count))
+                return -EFAULT;
+        kaddr[count] = '\0';
+        ret = cd->cache_parse(cd, kaddr, count);
+        if (!ret)
+                ret = count;
+        return ret;
+}
 
-static ssize_t
-cache_write(struct file *filp, const char __user *buf, size_t count,
-            loff_t *ppos)
+static ssize_t cache_slow_downcall(const char __user *buf,
+                                   size_t count, struct cache_detail *cd)
 {
-        int err;
-        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
+        static char write_buf[8192]; /* protected by queue_io_mutex */
+        ssize_t ret = -EINVAL;
 
-        if (count == 0)
-                return 0;
         if (count >= sizeof(write_buf))
-                return -EINVAL;
-
+                goto out;
         mutex_lock(&queue_io_mutex);
+        ret = cache_do_downcall(write_buf, buf, count, cd);
+        mutex_unlock(&queue_io_mutex);
+out:
+        return ret;
+}
 
-        if (copy_from_user(write_buf, buf, count)) {
-                mutex_unlock(&queue_io_mutex);
-                return -EFAULT;
-        }
-        write_buf[count] = '\0';
-        if (cd->cache_parse)
-                err = cd->cache_parse(cd, write_buf, count);
-        else
-                err = -EINVAL;
+static ssize_t cache_downcall(struct address_space *mapping,
+                              const char __user *buf,
+                              size_t count, struct cache_detail *cd)
+{
+        struct page *page;
+        char *kaddr;
+        ssize_t ret = -ENOMEM;
+
+        if (count >= PAGE_CACHE_SIZE)
+                goto out_slow;
+
+        page = find_or_create_page(mapping, 0, GFP_KERNEL);
+        if (!page)
+                goto out_slow;
+
+        kaddr = kmap(page);
+        ret = cache_do_downcall(kaddr, buf, count, cd);
+        kunmap(page);
+        unlock_page(page);
+        page_cache_release(page);
+        return ret;
+out_slow:
+        return cache_slow_downcall(buf, count, cd);
+}
 
-        mutex_unlock(&queue_io_mutex);
-        return err ? err : count;
+static ssize_t cache_write(struct file *filp, const char __user *buf,
+                           size_t count, loff_t *ppos,
+                           struct cache_detail *cd)
+{
+        struct address_space *mapping = filp->f_mapping;
+        struct inode *inode = filp->f_path.dentry->d_inode;
+        ssize_t ret = -EINVAL;
+
+        if (!cd->cache_parse)
+                goto out;
+
+        mutex_lock(&inode->i_mutex);
+        ret = cache_downcall(mapping, buf, count, cd);
+        mutex_unlock(&inode->i_mutex);
+out:
+        return ret;
 }
 
 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
 
-static unsigned int
-cache_poll(struct file *filp, poll_table *wait)
+static unsigned int cache_poll(struct file *filp, poll_table *wait,
+                               struct cache_detail *cd)
 {
         unsigned int mask;
         struct cache_reader *rp = filp->private_data;
         struct cache_queue *cq;
-        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
 
         poll_wait(filp, &queue_wait, wait);
 
@@ -822,14 +802,13 @@ cache_poll(struct file *filp, poll_table *wait)
         return mask;
 }
 
-static int
-cache_ioctl(struct inode *ino, struct file *filp,
-            unsigned int cmd, unsigned long arg)
+static int cache_ioctl(struct inode *ino, struct file *filp,
+                       unsigned int cmd, unsigned long arg,
+                       struct cache_detail *cd)
 {
         int len = 0;
         struct cache_reader *rp = filp->private_data;
         struct cache_queue *cq;
-        struct cache_detail *cd = PDE(ino)->data;
 
         if (cmd != FIONREAD || !rp)
                 return -EINVAL;
@@ -852,15 +831,13 @@ cache_ioctl(struct inode *ino, struct file *filp,
         return put_user(len, (int __user *)arg);
 }
 
-static int
-cache_open(struct inode *inode, struct file *filp)
+static int cache_open(struct inode *inode, struct file *filp,
+                      struct cache_detail *cd)
 {
         struct cache_reader *rp = NULL;
 
         nonseekable_open(inode, filp);
         if (filp->f_mode & FMODE_READ) {
-                struct cache_detail *cd = PDE(inode)->data;
-
                 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
                 if (!rp)
                         return -ENOMEM;
@@ -875,11 +852,10 @@ cache_open(struct inode *inode, struct file *filp)
         return 0;
 }
 
-static int
-cache_release(struct inode *inode, struct file *filp)
+static int cache_release(struct inode *inode, struct file *filp,
+                         struct cache_detail *cd)
 {
         struct cache_reader *rp = filp->private_data;
-        struct cache_detail *cd = PDE(inode)->data;
 
         if (rp) {
                 spin_lock(&queue_lock);
@@ -908,18 +884,6 @@ cache_release(struct inode *inode, struct file *filp)
 
 
 
-static const struct file_operations cache_file_operations = {
-        .owner          = THIS_MODULE,
-        .llseek         = no_llseek,
-        .read           = cache_read,
-        .write          = cache_write,
-        .poll           = cache_poll,
-        .ioctl          = cache_ioctl, /* for FIONREAD */
-        .open           = cache_open,
-        .release        = cache_release,
-};
-
-
 static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
 {
         struct cache_queue *cq;
@@ -1020,15 +984,21 @@ static void warn_no_listener(struct cache_detail *detail)
         if (detail->last_warn != detail->last_close) {
                 detail->last_warn = detail->last_close;
                 if (detail->warn_no_listener)
-                        detail->warn_no_listener(detail);
+                        detail->warn_no_listener(detail, detail->last_close != 0);
         }
 }
 
 /*
- * register an upcall request to user-space.
+ * register an upcall request to user-space and queue it up for read() by the
+ * upcall daemon.
+ *
  * Each request is at most one page long.
  */
-static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
+int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h,
+                void (*cache_request)(struct cache_detail *,
+                                      struct cache_head *,
+                                      char **,
+                                      int *))
 {
 
         char *buf;
@@ -1036,9 +1006,6 @@ static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
         char *bp;
         int len;
 
-        if (detail->cache_request == NULL)
-                return -EINVAL;
-
         if (atomic_read(&detail->readers) == 0 &&
             detail->last_close < get_seconds() - 30) {
                         warn_no_listener(detail);
@@ -1057,7 +1024,7 @@ static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
 
         bp = buf; len = PAGE_SIZE;
 
-        detail->cache_request(detail, h, &bp, &len);
+        cache_request(detail, h, &bp, &len);
 
         if (len < 0) {
                 kfree(buf);
@@ -1075,6 +1042,7 @@ static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
         wake_up(&queue_wait);
         return 0;
 }
+EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
 
 /*
  * parse a message from user-space and pass it
@@ -1242,10 +1210,10 @@ static const struct seq_operations cache_content_op = {
         .show   = c_show,
 };
 
-static int content_open(struct inode *inode, struct file *file)
+static int content_open(struct inode *inode, struct file *file,
+                        struct cache_detail *cd)
 {
         struct handle *han;
-        struct cache_detail *cd = PDE(inode)->data;
 
         han = __seq_open_private(file, &cache_content_op, sizeof(*han));
         if (han == NULL)
@@ -1255,17 +1223,10 @@ static int content_open(struct inode *inode, struct file *file)
         return 0;
 }
 
-static const struct file_operations content_file_operations = {
-        .open           = content_open,
-        .read           = seq_read,
-        .llseek         = seq_lseek,
-        .release        = seq_release_private,
-};
-
 static ssize_t read_flush(struct file *file, char __user *buf,
-                            size_t count, loff_t *ppos)
+                          size_t count, loff_t *ppos,
+                          struct cache_detail *cd)
 {
-        struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
         char tbuf[20];
         unsigned long p = *ppos;
         size_t len;
@@ -1283,10 +1244,10 @@ static ssize_t read_flush(struct file *file, char __user *buf,
         return len;
 }
 
-static ssize_t write_flush(struct file * file, const char __user * buf,
-                             size_t count, loff_t *ppos)
+static ssize_t write_flush(struct file *file, const char __user *buf,
+                           size_t count, loff_t *ppos,
+                           struct cache_detail *cd)
 {
-        struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
         char tbuf[20];
         char *ep;
         long flushtime;
@@ -1307,8 +1268,299 @@ static ssize_t write_flush(struct file * file, const char __user * buf,
         return count;
 }
 
-static const struct file_operations cache_flush_operations = {
+static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
+                                 size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
+
+        return cache_read(filp, buf, count, ppos, cd);
+}
+
+static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
+                                  size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
+
+        return cache_write(filp, buf, count, ppos, cd);
+}
+
+static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
+{
+        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
+
+        return cache_poll(filp, wait, cd);
+}
+
+static int cache_ioctl_procfs(struct inode *inode, struct file *filp,
+                              unsigned int cmd, unsigned long arg)
+{
+        struct cache_detail *cd = PDE(inode)->data;
+
+        return cache_ioctl(inode, filp, cmd, arg, cd);
+}
+
+static int cache_open_procfs(struct inode *inode, struct file *filp)
+{
+        struct cache_detail *cd = PDE(inode)->data;
+
+        return cache_open(inode, filp, cd);
+}
+
+static int cache_release_procfs(struct inode *inode, struct file *filp)
+{
+        struct cache_detail *cd = PDE(inode)->data;
+
+        return cache_release(inode, filp, cd);
+}
+
+static const struct file_operations cache_file_operations_procfs = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .read           = cache_read_procfs,
+        .write          = cache_write_procfs,
+        .poll           = cache_poll_procfs,
+        .ioctl          = cache_ioctl_procfs, /* for FIONREAD */
+        .open           = cache_open_procfs,
+        .release        = cache_release_procfs,
+};
+
+static int content_open_procfs(struct inode *inode, struct file *filp)
+{
+        struct cache_detail *cd = PDE(inode)->data;
+
+        return content_open(inode, filp, cd);
+}
+
+static const struct file_operations content_file_operations_procfs = {
+        .open           = content_open_procfs,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = seq_release_private,
+};
+
+static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
+                            size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
+
+        return read_flush(filp, buf, count, ppos, cd);
+}
+
+static ssize_t write_flush_procfs(struct file *filp,
+                                  const char __user *buf,
+                                  size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
+
+        return write_flush(filp, buf, count, ppos, cd);
+}
+
+static const struct file_operations cache_flush_operations_procfs = {
+        .open           = nonseekable_open,
+        .read           = read_flush_procfs,
+        .write          = write_flush_procfs,
+};
+
+static void remove_cache_proc_entries(struct cache_detail *cd)
+{
+        if (cd->u.procfs.proc_ent == NULL)
+                return;
+        if (cd->u.procfs.flush_ent)
+                remove_proc_entry("flush", cd->u.procfs.proc_ent);
+        if (cd->u.procfs.channel_ent)
+                remove_proc_entry("channel", cd->u.procfs.proc_ent);
+        if (cd->u.procfs.content_ent)
+                remove_proc_entry("content", cd->u.procfs.proc_ent);
+        cd->u.procfs.proc_ent = NULL;
+        remove_proc_entry(cd->name, proc_net_rpc);
+}
+
+#ifdef CONFIG_PROC_FS
+static int create_cache_proc_entries(struct cache_detail *cd)
+{
+        struct proc_dir_entry *p;
+
+        cd->u.procfs.proc_ent = proc_mkdir(cd->name, proc_net_rpc);
+        if (cd->u.procfs.proc_ent == NULL)
+                goto out_nomem;
+        cd->u.procfs.channel_ent = NULL;
+        cd->u.procfs.content_ent = NULL;
+
+        p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
+                             cd->u.procfs.proc_ent,
+                             &cache_flush_operations_procfs, cd);
+        cd->u.procfs.flush_ent = p;
+        if (p == NULL)
+                goto out_nomem;
+
+        if (cd->cache_upcall || cd->cache_parse) {
+                p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
+                                     cd->u.procfs.proc_ent,
+                                     &cache_file_operations_procfs, cd);
+                cd->u.procfs.channel_ent = p;
+                if (p == NULL)
+                        goto out_nomem;
+        }
+        if (cd->cache_show) {
+                p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
+                                cd->u.procfs.proc_ent,
+                                &content_file_operations_procfs, cd);
+                cd->u.procfs.content_ent = p;
+                if (p == NULL)
+                        goto out_nomem;
+        }
+        return 0;
+out_nomem:
+        remove_cache_proc_entries(cd);
+        return -ENOMEM;
+}
+#else /* CONFIG_PROC_FS */
+static int create_cache_proc_entries(struct cache_detail *cd)
+{
+        return 0;
+}
+#endif
+
+int cache_register(struct cache_detail *cd)
+{
+        int ret;
+
+        sunrpc_init_cache_detail(cd);
+        ret = create_cache_proc_entries(cd);
+        if (ret)
+                sunrpc_destroy_cache_detail(cd);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cache_register);
+
+void cache_unregister(struct cache_detail *cd)
+{
+        remove_cache_proc_entries(cd);
+        sunrpc_destroy_cache_detail(cd);
+}
+EXPORT_SYMBOL_GPL(cache_unregister);
+
+static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
+                                 size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
+
+        return cache_read(filp, buf, count, ppos, cd);
+}
+
+static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
+                                  size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
+
+        return cache_write(filp, buf, count, ppos, cd);
+}
+
+static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
+{
+        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
+
+        return cache_poll(filp, wait, cd);
+}
+
+static int cache_ioctl_pipefs(struct inode *inode, struct file *filp,
+                              unsigned int cmd, unsigned long arg)
+{
+        struct cache_detail *cd = RPC_I(inode)->private;
+
+        return cache_ioctl(inode, filp, cmd, arg, cd);
+}
+
+static int cache_open_pipefs(struct inode *inode, struct file *filp)
+{
+        struct cache_detail *cd = RPC_I(inode)->private;
+
+        return cache_open(inode, filp, cd);
+}
+
+static int cache_release_pipefs(struct inode *inode, struct file *filp)
+{
+        struct cache_detail *cd = RPC_I(inode)->private;
+
+        return cache_release(inode, filp, cd);
+}
+
+const struct file_operations cache_file_operations_pipefs = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .read           = cache_read_pipefs,
+        .write          = cache_write_pipefs,
+        .poll           = cache_poll_pipefs,
+        .ioctl          = cache_ioctl_pipefs, /* for FIONREAD */
+        .open           = cache_open_pipefs,
+        .release        = cache_release_pipefs,
+};
+
+static int content_open_pipefs(struct inode *inode, struct file *filp)
+{
+        struct cache_detail *cd = RPC_I(inode)->private;
+
+        return content_open(inode, filp, cd);
+}
+
+const struct file_operations content_file_operations_pipefs = {
+        .open           = content_open_pipefs,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = seq_release_private,
+};
+
+static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
+                            size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
+
+        return read_flush(filp, buf, count, ppos, cd);
+}
+
+static ssize_t write_flush_pipefs(struct file *filp,
+                                  const char __user *buf,
+                                  size_t count, loff_t *ppos)
+{
+        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
+
+        return write_flush(filp, buf, count, ppos, cd);
+}
+
+const struct file_operations cache_flush_operations_pipefs = {
         .open           = nonseekable_open,
-        .read           = read_flush,
-        .write          = write_flush,
+        .read           = read_flush_pipefs,
+        .write          = write_flush_pipefs,
 };
+
+int sunrpc_cache_register_pipefs(struct dentry *parent,
+                                 const char *name, mode_t umode,
+                                 struct cache_detail *cd)
+{
+        struct qstr q;
+        struct dentry *dir;
+        int ret = 0;
+
+        sunrpc_init_cache_detail(cd);
+        q.name = name;
+        q.len = strlen(name);
+        q.hash = full_name_hash(q.name, q.len);
+        dir = rpc_create_cache_dir(parent, &q, umode, cd);
+        if (!IS_ERR(dir))
+                cd->u.pipefs.dir = dir;
+        else {
+                sunrpc_destroy_cache_detail(cd);
+                ret = PTR_ERR(dir);
+        }
+        return ret;
+}
+EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
+
+void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
+{
+        rpc_remove_cache_dir(cd->u.pipefs.dir);
+        cd->u.pipefs.dir = NULL;
+        sunrpc_destroy_cache_detail(cd);
+}
+EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
+