1 files changed, 257 insertions, 2 deletions

diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 2f84adaad42..9a16bad5d2e 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -13,9 +13,12 @@
 #include <linux/nfs_fs.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
+#include <linux/namei.h>
 
 #include "internal.h"
 #include "nfs4_fs.h"
+#include "iostat.h"
+#include "delegation.h"
 
 struct nfs_unlinkdata {
         struct hlist_node list;
@@ -244,7 +247,7 @@ void nfs_unblock_sillyrename(struct dentry *dentry)
  * @dir: parent directory of dentry
  * @dentry: dentry to unlink
  */
-int
+static int
 nfs_async_unlink(struct inode *dir, struct dentry *dentry)
 {
         struct nfs_unlinkdata *data;
@@ -259,7 +262,6 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
                 status = PTR_ERR(data->cred);
                 goto out_free;
         }
-        data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
         data->res.dir_attr = &data->dir_attr;
 
         status = -EBUSY;
@@ -303,3 +305,256 @@ nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
         if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
                 nfs_free_unlinkdata(data);
 }
+
+/* Cancel a queued async unlink. Called when a sillyrename run fails. */
+static void
+nfs_cancel_async_unlink(struct dentry *dentry)
+{
+        spin_lock(&dentry->d_lock);
+        if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+                struct nfs_unlinkdata *data = dentry->d_fsdata;
+
+                dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+                spin_unlock(&dentry->d_lock);
+                nfs_free_unlinkdata(data);
+                return;
+        }
+        spin_unlock(&dentry->d_lock);
+}
+
+struct nfs_renamedata {
+        struct nfs_renameargs   args;
+        struct nfs_renameres    res;
+        struct rpc_cred         *cred;
+        struct inode            *old_dir;
+        struct dentry           *old_dentry;
+        struct nfs_fattr        old_fattr;
+        struct inode            *new_dir;
+        struct dentry           *new_dentry;
+        struct nfs_fattr        new_fattr;
+};
+
+/**
+ * nfs_async_rename_done - Sillyrename post-processing
+ * @task: rpc_task of the sillyrename
+ * @calldata: nfs_renamedata for the sillyrename
+ *
+ * Do the directory attribute updates and the d_move
+ */
+static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
+{
+        struct nfs_renamedata *data = calldata;
+        struct inode *old_dir = data->old_dir;
+        struct inode *new_dir = data->new_dir;
+
+        if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
+                nfs_restart_rpc(task, NFS_SERVER(old_dir)->nfs_client);
+                return;
+        }
+
+        if (task->tk_status != 0) {
+                nfs_cancel_async_unlink(data->old_dentry);
+                return;
+        }
+
+        nfs_set_verifier(data->old_dentry, nfs_save_change_attribute(old_dir));
+        d_move(data->old_dentry, data->new_dentry);
+}
+
+/**
+ * nfs_async_rename_release - Release the sillyrename data.
+ * @calldata: the struct nfs_renamedata to be released
+ */
+static void nfs_async_rename_release(void *calldata)
+{
+        struct nfs_renamedata   *data = calldata;
+        struct super_block *sb = data->old_dir->i_sb;
+
+        if (data->old_dentry->d_inode)
+                nfs_mark_for_revalidate(data->old_dentry->d_inode);
+
+        dput(data->old_dentry);
+        dput(data->new_dentry);
+        iput(data->old_dir);
+        iput(data->new_dir);
+        nfs_sb_deactive(sb);
+        put_rpccred(data->cred);
+        kfree(data);
+}
+
+#if defined(CONFIG_NFS_V4_1)
+static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
+{
+        struct nfs_renamedata *data = calldata;
+        struct nfs_server *server = NFS_SERVER(data->old_dir);
+
+        if (nfs4_setup_sequence(server, &data->args.seq_args,
+                                &data->res.seq_res, 1, task))
+                return;
+        rpc_call_start(task);
+}
+#endif /* CONFIG_NFS_V4_1 */
+
+static const struct rpc_call_ops nfs_rename_ops = {
+        .rpc_call_done = nfs_async_rename_done,
+        .rpc_release = nfs_async_rename_release,
+#if defined(CONFIG_NFS_V4_1)
+        .rpc_call_prepare = nfs_rename_prepare,
+#endif /* CONFIG_NFS_V4_1 */
+};
+
+/**
+ * nfs_async_rename - perform an asynchronous rename operation
+ * @old_dir: directory that currently holds the dentry to be renamed
+ * @new_dir: target directory for the rename
+ * @old_dentry: original dentry to be renamed
+ * @new_dentry: dentry to which the old_dentry should be renamed
+ *
+ * It's expected that valid references to the dentries and inodes are held
+ */
+static struct rpc_task *
+nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
+                 struct dentry *old_dentry, struct dentry *new_dentry)
+{
+        struct nfs_renamedata *data;
+        struct rpc_message msg = { };
+        struct rpc_task_setup task_setup_data = {
+                .rpc_message = &msg,
+                .callback_ops = &nfs_rename_ops,
+                .workqueue = nfsiod_workqueue,
+                .rpc_client = NFS_CLIENT(old_dir),
+                .flags = RPC_TASK_ASYNC,
+        };
+
+        data = kzalloc(sizeof(*data), GFP_KERNEL);
+        if (data == NULL)
+                return ERR_PTR(-ENOMEM);
+        task_setup_data.callback_data = data,
+
+        data->cred = rpc_lookup_cred();
+        if (IS_ERR(data->cred)) {
+                struct rpc_task *task = ERR_CAST(data->cred);
+                kfree(data);
+                return task;
+        }
+
+        msg.rpc_argp = &data->args;
+        msg.rpc_resp = &data->res;
+        msg.rpc_cred = data->cred;
+
+        /* set up nfs_renamedata */
+        data->old_dir = old_dir;
+        atomic_inc(&old_dir->i_count);
+        data->new_dir = new_dir;
+        atomic_inc(&new_dir->i_count);
+        data->old_dentry = dget(old_dentry);
+        data->new_dentry = dget(new_dentry);
+        nfs_fattr_init(&data->old_fattr);
+        nfs_fattr_init(&data->new_fattr);
+
+        /* set up nfs_renameargs */
+        data->args.old_dir = NFS_FH(old_dir);
+        data->args.old_name = &old_dentry->d_name;
+        data->args.new_dir = NFS_FH(new_dir);
+        data->args.new_name = &new_dentry->d_name;
+
+        /* set up nfs_renameres */
+        data->res.old_fattr = &data->old_fattr;
+        data->res.new_fattr = &data->new_fattr;
+
+        nfs_sb_active(old_dir->i_sb);
+
+        NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
+
+        return rpc_run_task(&task_setup_data);
+}
+
+/**
+ * nfs_sillyrename - Perform a silly-rename of a dentry
+ * @dir: inode of directory that contains dentry
+ * @dentry: dentry to be sillyrenamed
+ *
+ * NFSv2/3 is stateless and the server doesn't know when the client is
+ * holding a file open. To prevent application problems when a file is
+ * unlinked while it's still open, the client performs a "silly-rename".
+ * That is, it renames the file to a hidden file in the same directory,
+ * and only performs the unlink once the last reference to it is put.
+ *
+ * The final cleanup is done during dentry_iput.
+ */
+int
+nfs_sillyrename(struct inode *dir, struct dentry *dentry)
+{
+        static unsigned int sillycounter;
+        const int      fileidsize  = sizeof(NFS_FILEID(dentry->d_inode))*2;
+        const int      countersize = sizeof(sillycounter)*2;
+        const int      slen        = sizeof(".nfs")+fileidsize+countersize-1;
+        char           silly[slen+1];
+        struct dentry *sdentry;
+        struct rpc_task *task;
+        int            error = -EIO;
+
+        dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
+                dentry->d_parent->d_name.name, dentry->d_name.name,
+                atomic_read(&dentry->d_count));
+        nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
+
+        /*
+         * We don't allow a dentry to be silly-renamed twice.
+         */
+        error = -EBUSY;
+        if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+                goto out;
+
+        sprintf(silly, ".nfs%*.*Lx",
+                fileidsize, fileidsize,
+                (unsigned long long)NFS_FILEID(dentry->d_inode));
+
+        /* Return delegation in anticipation of the rename */
+        nfs_inode_return_delegation(dentry->d_inode);
+
+        sdentry = NULL;
+        do {
+                char *suffix = silly + slen - countersize;
+
+                dput(sdentry);
+                sillycounter++;
+                sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
+
+                dfprintk(VFS, "NFS: trying to rename %s to %s\n",
+                                dentry->d_name.name, silly);
+
+                sdentry = lookup_one_len(silly, dentry->d_parent, slen);
+                /*
+                 * N.B. Better to return EBUSY here ... it could be
+                 * dangerous to delete the file while it's in use.
+                 */
+                if (IS_ERR(sdentry))
+                        goto out;
+        } while (sdentry->d_inode != NULL); /* need negative lookup */
+
+        /* queue unlink first. Can't do this from rpc_release as it
+         * has to allocate memory
+         */
+        error = nfs_async_unlink(dir, dentry);
+        if (error)
+                goto out_dput;
+
+        /* run the rename task, undo unlink if it fails */
+        task = nfs_async_rename(dir, dir, dentry, sdentry);
+        if (IS_ERR(task)) {
+                error = -EBUSY;
+                nfs_cancel_async_unlink(dentry);
+                goto out_dput;
+        }
+
+        /* wait for the RPC task to complete, unless a SIGKILL intervenes */
+        error = rpc_wait_for_completion_task(task);
+        if (error == 0)
+                error = task->tk_status;
+        rpc_put_task(task);
+out_dput:
+        dput(sdentry);
+out:
+        return error;
+}