SUNRPC: Clean up the sillyrename code

Fix a couple of bugs:
 - Don't rely on the parent dentry still being valid when the call completes.
   Fixes a race with shrink_dcache_for_umount_subtree()

 - Don't remove the file if the filehandle has been labelled as stale.

Fix a couple of inefficiencies
 - Remove the global list of sillyrenamed files. Instead we can cache the
   sillyrename information in the dentry->d_fsdata
 - Move common code from unlink_setup/unlink_done into fs/nfs/unlink.c

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 86 insertions, 109 deletions

diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 0e28189c2151..045ab805c17f 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -3,7 +3,6 @@
  *
  * nfs sillydelete handling
  *
- * NOTE: we rely on holding the BKL for list manipulation protection.
  */
 
 #include <linux/slab.h>
@@ -15,46 +14,23 @@
 
 
 struct nfs_unlinkdata {
-        struct nfs_unlinkdata   *next;
-        struct dentry   *dir, *dentry;
-        struct qstr     name;
-        struct rpc_task task;
+        struct nfs_removeargs args;
+        struct nfs_removeres res;
+        struct inode *dir;
         struct rpc_cred *cred;
-        unsigned int    count;
 };
 
-static struct nfs_unlinkdata    *nfs_deletes;
-static RPC_WAITQ(nfs_delete_queue, "nfs_delete_queue");
-
-/**
- * nfs_detach_unlinkdata - Remove asynchronous unlink from global list
- * @data: pointer to descriptor
- */
-static inline void
-nfs_detach_unlinkdata(struct nfs_unlinkdata *data)
-{
-        struct nfs_unlinkdata   **q;
-
-        for (q = &nfs_deletes; *q != NULL; q = &((*q)->next)) {
-                if (*q == data) {
-                        *q = data->next;
-                        break;
-                }
-        }
-}
-
 /**
- * nfs_put_unlinkdata - release data from a sillydelete operation.
+ * nfs_free_unlinkdata - release data from a sillydelete operation.
  * @data: pointer to unlink structure.
  */
 static void
-nfs_put_unlinkdata(struct nfs_unlinkdata *data)
+nfs_free_unlinkdata(struct nfs_unlinkdata *data)
 {
-        if (--data->count == 0) {
-                nfs_detach_unlinkdata(data);
-                kfree(data->name.name);
-                kfree(data);
-        }
+        iput(data->dir);
+        put_rpccred(data->cred);
+        kfree(data->args.name.name);
+        kfree(data);
 }
 
 #define NAME_ALLOC_LEN(len)     ((len+16) & ~15)
@@ -63,50 +39,36 @@ nfs_put_unlinkdata(struct nfs_unlinkdata *data)
  * @dentry: pointer to dentry
  * @data: nfs_unlinkdata
  */
-static inline void
-nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
+static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
 {
         char            *str;
         int             len = dentry->d_name.len;
 
-        str = kmalloc(NAME_ALLOC_LEN(len), GFP_KERNEL);
+        str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
         if (!str)
-                return;
-        memcpy(str, dentry->d_name.name, len);
-        if (!data->name.len) {
-                data->name.len = len;
-                data->name.name = str;
-        } else
-                kfree(str);
+                return -ENOMEM;
+        data->args.name.len = len;
+        data->args.name.name = str;
+        return 0;
 }
 
 /**
  * nfs_async_unlink_init - Initialize the RPC info
- * @task: rpc_task of the sillydelete
- *
- * We delay initializing RPC info until after the call to dentry_iput()
- * in order to minimize races against rename().
+ * task: rpc_task of the sillydelete
  */
 static void nfs_async_unlink_init(struct rpc_task *task, void *calldata)
 {
-        struct nfs_unlinkdata   *data = calldata;
-        struct dentry           *dir = data->dir;
-        struct rpc_message      msg = {
-                .rpc_cred       = data->cred,
+        struct nfs_unlinkdata *data = calldata;
+        struct inode *dir = data->dir;
+        struct rpc_message msg = {
+                .rpc_argp = &data->args,
+                .rpc_resp = &data->res,
+                .rpc_cred = data->cred,
         };
-        int                     status = -ENOENT;
-
-        if (!data->name.len)
-                goto out_err;
 
-        status = NFS_PROTO(dir->d_inode)->unlink_setup(&msg, dir, &data->name);
-        if (status < 0)
-                goto out_err;
-        nfs_begin_data_update(dir->d_inode);
+        nfs_begin_data_update(dir);
+        NFS_PROTO(dir)->unlink_setup(&msg, dir);
         rpc_call_setup(task, &msg, 0);
-        return;
- out_err:
-        rpc_exit(task, status);
 }
 
 /**
@@ -117,19 +79,13 @@ static void nfs_async_unlink_init(struct rpc_task *task, void *calldata)
  */
 static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
 {
-        struct nfs_unlinkdata   *data = calldata;
-        struct dentry           *dir = data->dir;
-        struct inode            *dir_i;
-
-        if (!dir)
-                return;
-        dir_i = dir->d_inode;
-        nfs_end_data_update(dir_i);
-        if (NFS_PROTO(dir_i)->unlink_done(dir, task))
-                return;
-        put_rpccred(data->cred);
-        data->cred = NULL;
-        dput(dir);
+        struct nfs_unlinkdata *data = calldata;
+        struct inode *dir = data->dir;
+
+        if (!NFS_PROTO(dir)->unlink_done(task, dir))
+                rpc_restart_call(task);
+        else
+                nfs_end_data_update(dir);
 }
 
 /**
@@ -142,7 +98,7 @@ static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
 static void nfs_async_unlink_release(void *calldata)
 {
         struct nfs_unlinkdata   *data = calldata;
-        nfs_put_unlinkdata(data);
+        nfs_free_unlinkdata(data);
 }
 
 static const struct rpc_call_ops nfs_unlink_ops = {
@@ -151,73 +107,94 @@ static const struct rpc_call_ops nfs_unlink_ops = {
         .rpc_release = nfs_async_unlink_release,
 };
 
+static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
+{
+        struct rpc_task *task;
+        struct dentry *parent;
+        struct inode *dir;
+
+        if (nfs_copy_dname(dentry, data) < 0)
+                goto out_free;
+
+        parent = dget_parent(dentry);
+        if (parent == NULL)
+                goto out_free;
+        dir = igrab(parent->d_inode);
+        dput(parent);
+        if (dir == NULL)
+                goto out_free;
+
+        data->dir = dir;
+        data->args.fh = NFS_FH(dir);
+        nfs_fattr_init(&data->res.dir_attr);
+
+        task = rpc_run_task(NFS_CLIENT(dir), RPC_TASK_ASYNC, &nfs_unlink_ops, data);
+        if (!IS_ERR(task))
+                rpc_put_task(task);
+        return 1;
+out_free:
+        return 0;
+}
+
 /**
  * nfs_async_unlink - asynchronous unlinking of a file
+ * @dir: parent directory of dentry
  * @dentry: dentry to unlink
  */
 int
-nfs_async_unlink(struct dentry *dentry)
+nfs_async_unlink(struct inode *dir, struct dentry *dentry)
 {
-        struct dentry   *dir = dentry->d_parent;
-        struct nfs_unlinkdata   *data;
-        struct rpc_clnt *clnt = NFS_CLIENT(dir->d_inode);
-        int             status = -ENOMEM;
+        struct nfs_unlinkdata *data;
+        int status = -ENOMEM;
 
         data = kzalloc(sizeof(*data), GFP_KERNEL);
-        if (!data)
+        if (data == NULL)
                 goto out;
 
-        data->cred = rpcauth_lookupcred(clnt->cl_auth, 0);
+        data->cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
         if (IS_ERR(data->cred)) {
                 status = PTR_ERR(data->cred);
                 goto out_free;
         }
-        data->dir = dget(dir);
-        data->dentry = dentry;
-
-        data->next = nfs_deletes;
-        nfs_deletes = data;
-        data->count = 1;
-
-        rpc_init_task(&data->task, clnt, RPC_TASK_ASYNC, &nfs_unlink_ops, data);
 
+        status = -EBUSY;
         spin_lock(&dentry->d_lock);
+        if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+                goto out_unlock;
         dentry->d_flags |= DCACHE_NFSFS_RENAMED;
+        dentry->d_fsdata = data;
         spin_unlock(&dentry->d_lock);
-
-        rpc_sleep_on(&nfs_delete_queue, &data->task, NULL, NULL);
-        status = 0;
- out:
-        return status;
+        return 0;
+out_unlock:
+        spin_unlock(&dentry->d_lock);
+        put_rpccred(data->cred);
 out_free:
         kfree(data);
+out:
         return status;
 }
 
 /**
  * nfs_complete_unlink - Initialize completion of the sillydelete
  * @dentry: dentry to delete
+ * @inode: inode
  *
  * Since we're most likely to be called by dentry_iput(), we
  * only use the dentry to find the sillydelete. We then copy the name
  * into the qstr.
  */
 void
-nfs_complete_unlink(struct dentry *dentry)
+nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
 {
-        struct nfs_unlinkdata   *data;
+        struct nfs_unlinkdata   *data = NULL;
 
-        for(data = nfs_deletes; data != NULL; data = data->next) {
-                if (dentry == data->dentry)
-                        break;
-        }
-        if (!data)
-                return;
-        data->count++;
-        nfs_copy_dname(dentry, data);
         spin_lock(&dentry->d_lock);
-        dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+        if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+                dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+                data = dentry->d_fsdata;
+        }
         spin_unlock(&dentry->d_lock);
-        rpc_wake_up_task(&data->task);
-        nfs_put_unlinkdata(data);
+
+        if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
+                nfs_free_unlinkdata(data);
 }