5 files changed, 127 insertions, 18 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 8ec7fbd8240c..35334539d947 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -562,6 +562,7 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
         nfs_fattr_init(&fattr);
         desc->entry = &my_entry;
 
+        nfs_block_sillyrename(dentry);
         while(!desc->entry->eof) {
                 res = readdir_search_pagecache(desc);
 
@@ -592,6 +593,7 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
                         break;
                 }
         }
+        nfs_unblock_sillyrename(dentry);
         unlock_kernel();
         if (res > 0)
                 res = 0;
@@ -866,6 +868,7 @@ struct dentry_operations nfs_dentry_operations = {
 static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
 {
         struct dentry *res;
+        struct dentry *parent;
         struct inode *inode = NULL;
         int error;
         struct nfs_fh fhandle;
@@ -894,26 +897,31 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
                 goto out_unlock;
         }
 
+        parent = dentry->d_parent;
+        /* Protect against concurrent sillydeletes */
+        nfs_block_sillyrename(parent);
         error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
         if (error == -ENOENT)
                 goto no_entry;
         if (error < 0) {
                 res = ERR_PTR(error);
-                goto out_unlock;
+                goto out_unblock_sillyrename;
         }
         inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
         res = (struct dentry *)inode;
         if (IS_ERR(res))
-                goto out_unlock;
+                goto out_unblock_sillyrename;
 
 no_entry:
         res = d_materialise_unique(dentry, inode);
         if (res != NULL) {
                 if (IS_ERR(res))
-                        goto out_unlock;
+                        goto out_unblock_sillyrename;
                 dentry = res;
         }
         nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+out_unblock_sillyrename:
+        nfs_unblock_sillyrename(parent);
 out_unlock:
         unlock_kernel();
 out:
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 6d2f2a3eccf8..173e294dffc5 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1169,6 +1169,9 @@ static void init_once(struct kmem_cache * cachep, void *foo)
         INIT_RADIX_TREE(&nfsi->nfs_page_tree, GFP_ATOMIC);
         nfsi->ncommit = 0;
         nfsi->npages = 0;
+        atomic_set(&nfsi->silly_count, 1);
+        INIT_HLIST_HEAD(&nfsi->silly_list);
+        init_waitqueue_head(&nfsi->waitqueue);
         nfs4_init_once(nfsi);
 }
 
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index cb99fd90a9ac..2cb3b8b71ee7 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1372,6 +1372,7 @@ out_close:
 struct dentry *
 nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
+        struct dentry *parent;
         struct path path = {
                 .mnt = nd->mnt,
                 .dentry = dentry,
@@ -1394,6 +1395,9 @@ nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
         cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
         if (IS_ERR(cred))
                 return (struct dentry *)cred;
+        parent = dentry->d_parent;
+        /* Protect against concurrent sillydeletes */
+        nfs_block_sillyrename(parent);
         state = nfs4_do_open(dir, &path, nd->intent.open.flags, &attr, cred);
         put_rpccred(cred);
         if (IS_ERR(state)) {
@@ -1401,12 +1405,14 @@ nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
                         d_add(dentry, NULL);
                         nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
                 }
+                nfs_unblock_sillyrename(parent);
                 return (struct dentry *)state;
         }
         res = d_add_unique(dentry, igrab(state->inode));
         if (res != NULL)
                 path.dentry = res;
         nfs_set_verifier(path.dentry, nfs_save_change_attribute(dir));
+        nfs_unblock_sillyrename(parent);
         nfs4_intent_set_file(nd, &path, state);
         return res;
 }
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 1aed850d18f2..6ecd46c967c8 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -14,6 +14,7 @@
 
 
 struct nfs_unlinkdata {
+        struct hlist_node list;
         struct nfs_removeargs args;
         struct nfs_removeres res;
         struct inode *dir;
@@ -52,6 +53,20 @@ static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
         return 0;
 }
 
+static void nfs_free_dname(struct nfs_unlinkdata *data)
+{
+        kfree(data->args.name.name);
+        data->args.name.name = NULL;
+        data->args.name.len = 0;
+}
+
+static void nfs_dec_sillycount(struct inode *dir)
+{
+        struct nfs_inode *nfsi = NFS_I(dir);
+        if (atomic_dec_return(&nfsi->silly_count) == 1)
+                wake_up(&nfsi->waitqueue);
+}
+
 /**
  * nfs_async_unlink_init - Initialize the RPC info
  * task: rpc_task of the sillydelete
@@ -95,6 +110,8 @@ 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_dec_sillycount(data->dir);
         nfs_free_unlinkdata(data);
 }
 
@@ -104,33 +121,100 @@ 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)
+static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
 {
         struct rpc_task *task;
+        struct dentry *alias;
+
+        alias = d_lookup(parent, &data->args.name);
+        if (alias != NULL) {
+                int ret = 0;
+                /*
+                 * Hey, we raced with lookup... See if we need to transfer
+                 * the sillyrename information to the aliased dentry.
+                 */
+                nfs_free_dname(data);
+                spin_lock(&alias->d_lock);
+                if (!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
+                        alias->d_fsdata = data;
+                        alias->d_flags ^= DCACHE_NFSFS_RENAMED;
+                        ret = 1;
+                }
+                spin_unlock(&alias->d_lock);
+                nfs_dec_sillycount(dir);
+                dput(alias);
+                return ret;
+        }
+        data->dir = igrab(dir);
+        if (!data->dir) {
+                nfs_dec_sillycount(dir);
+                return 0;
+        }
+        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;
+}
+
+static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
+{
         struct dentry *parent;
         struct inode *dir;
+        int ret = 0;
 
-        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);
+        dir = parent->d_inode;
+        if (nfs_copy_dname(dentry, data) == 0)
+                goto out_dput;
+        /* Non-exclusive lock protects against concurrent lookup() calls */
+        spin_lock(&dir->i_lock);
+        if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
+                /* Deferred delete */
+                hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
+                spin_unlock(&dir->i_lock);
+                ret = 1;
+                goto out_dput;
+        }
+        spin_unlock(&dir->i_lock);
+        ret = nfs_do_call_unlink(parent, dir, data);
+out_dput:
         dput(parent);
-        if (dir == NULL)
-                goto out_free;
+out_free:
+        return ret;
+}
 
-        data->dir = dir;
-        data->args.fh = NFS_FH(dir);
-        nfs_fattr_init(&data->res.dir_attr);
+void nfs_block_sillyrename(struct dentry *dentry)
+{
+        struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
 
-        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;
+        wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
+}
+
+void nfs_unblock_sillyrename(struct dentry *dentry)
+{
+        struct inode *dir = dentry->d_inode;
+        struct nfs_inode *nfsi = NFS_I(dir);
+        struct nfs_unlinkdata *data;
+
+        atomic_inc(&nfsi->silly_count);
+        spin_lock(&dir->i_lock);
+        while (!hlist_empty(&nfsi->silly_list)) {
+                if (!atomic_inc_not_zero(&nfsi->silly_count))
+                        break;
+                data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
+                hlist_del(&data->list);
+                spin_unlock(&dir->i_lock);
+                if (nfs_do_call_unlink(dentry, dir, data) == 0)
+                        nfs_free_unlinkdata(data);
+                spin_lock(&dir->i_lock);
+        }
+        spin_unlock(&dir->i_lock);
 }
 
 /**
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index c5164c257f71..e82a6ebc725d 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -160,6 +160,12 @@ struct nfs_inode {
         /* Open contexts for shared mmap writes */
         struct list_head        open_files;
 
+        /* Number of in-flight sillydelete RPC calls */
+        atomic_t                silly_count;
+        /* List of deferred sillydelete requests */
+        struct hlist_head       silly_list;
+        wait_queue_head_t       waitqueue;
+
 #ifdef CONFIG_NFS_V4
         struct nfs4_cached_acl  *nfs4_acl;
         /* NFSv4 state */
@@ -394,6 +400,8 @@ extern void nfs_release_automount_timer(void);
  */
 extern int  nfs_async_unlink(struct inode *dir, struct dentry *dentry);
 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
+extern void nfs_block_sillyrename(struct dentry *dentry);
+extern void nfs_unblock_sillyrename(struct dentry *dentry);
 
 /*
  * linux/fs/nfs/write.c