Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1562 insertions, 0 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
new file mode 100644
index 00000000000..73f96acd5d3
--- /dev/null
+++ b/fs/nfs/dir.c
@@ -0,0 +1,1562 @@
+/*
+ *  linux/fs/nfs/dir.c
+ *
+ *  Copyright (C) 1992  Rick Sladkey
+ *
+ *  nfs directory handling functions
+ *
+ * 10 Apr 1996	Added silly rename for unlink	--okir
+ * 28 Sep 1996	Improved directory cache --okir
+ * 23 Aug 1997  Claus Heine claus@momo.math.rwth-aachen.de 
+ *              Re-implemented silly rename for unlink, newly implemented
+ *              silly rename for nfs_rename() following the suggestions
+ *              of Olaf Kirch (okir) found in this file.
+ *              Following Linus comments on my original hack, this version
+ *              depends only on the dcache stuff and doesn't touch the inode
+ *              layer (iput() and friends).
+ *  6 Jun 1999	Cache readdir lookups in the page cache. -DaveM
+ */
+
+#include <linux/time.h>
+#include <linux/errno.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/pagemap.h>
+#include <linux/smp_lock.h>
+#include <linux/namei.h>
+
+#include "delegation.h"
+
+#define NFS_PARANOIA 1
+/* #define NFS_DEBUG_VERBOSE 1 */
+
+static int nfs_opendir(struct inode *, struct file *);
+static int nfs_readdir(struct file *, void *, filldir_t);
+static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *);
+static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *);
+static int nfs_mkdir(struct inode *, struct dentry *, int);
+static int nfs_rmdir(struct inode *, struct dentry *);
+static int nfs_unlink(struct inode *, struct dentry *);
+static int nfs_symlink(struct inode *, struct dentry *, const char *);
+static int nfs_link(struct dentry *, struct inode *, struct dentry *);
+static int nfs_mknod(struct inode *, struct dentry *, int, dev_t);
+static int nfs_rename(struct inode *, struct dentry *,
+		      struct inode *, struct dentry *);
+static int nfs_fsync_dir(struct file *, struct dentry *, int);
+
+struct file_operations nfs_dir_operations = {
+	.read		= generic_read_dir,
+	.readdir	= nfs_readdir,
+	.open		= nfs_opendir,
+	.release	= nfs_release,
+	.fsync		= nfs_fsync_dir,
+};
+
+struct inode_operations nfs_dir_inode_operations = {
+	.create		= nfs_create,
+	.lookup		= nfs_lookup,
+	.link		= nfs_link,
+	.unlink		= nfs_unlink,
+	.symlink	= nfs_symlink,
+	.mkdir		= nfs_mkdir,
+	.rmdir		= nfs_rmdir,
+	.mknod		= nfs_mknod,
+	.rename		= nfs_rename,
+	.permission	= nfs_permission,
+	.getattr	= nfs_getattr,
+	.setattr	= nfs_setattr,
+};
+
+#ifdef CONFIG_NFS_V4
+
+static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *);
+struct inode_operations nfs4_dir_inode_operations = {
+	.create		= nfs_create,
+	.lookup		= nfs_atomic_lookup,
+	.link		= nfs_link,
+	.unlink		= nfs_unlink,
+	.symlink	= nfs_symlink,
+	.mkdir		= nfs_mkdir,
+	.rmdir		= nfs_rmdir,
+	.mknod		= nfs_mknod,
+	.rename		= nfs_rename,
+	.permission	= nfs_permission,
+	.getattr	= nfs_getattr,
+	.setattr	= nfs_setattr,
+};
+
+#endif /* CONFIG_NFS_V4 */
+
+/*
+ * Open file
+ */
+static int
+nfs_opendir(struct inode *inode, struct file *filp)
+{
+	int res = 0;
+
+	lock_kernel();
+	/* Call generic open code in order to cache credentials */
+	if (!res)
+		res = nfs_open(inode, filp);
+	unlock_kernel();
+	return res;
+}
+
+typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int);
+typedef struct {
+	struct file	*file;
+	struct page	*page;
+	unsigned long	page_index;
+	u32		*ptr;
+	u64		target;
+	struct nfs_entry *entry;
+	decode_dirent_t	decode;
+	int		plus;
+	int		error;
+} nfs_readdir_descriptor_t;
+
+/* Now we cache directories properly, by stuffing the dirent
+ * data directly in the page cache.
+ *
+ * Inode invalidation due to refresh etc. takes care of
+ * _everything_, no sloppy entry flushing logic, no extraneous
+ * copying, network direct to page cache, the way it was meant
+ * to be.
+ *
+ * NOTE: Dirent information verification is done always by the
+ *	 page-in of the RPC reply, nowhere else, this simplies
+ *	 things substantially.
+ */
+static
+int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
+{
+	struct file	*file = desc->file;
+	struct inode	*inode = file->f_dentry->d_inode;
+	struct rpc_cred	*cred = nfs_file_cred(file);
+	unsigned long	timestamp;
+	int		error;
+
+	dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index);
+
+ again:
+	timestamp = jiffies;
+	error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page,
+					  NFS_SERVER(inode)->dtsize, desc->plus);
+	if (error < 0) {
+		/* We requested READDIRPLUS, but the server doesn't grok it */
+		if (error == -ENOTSUPP && desc->plus) {
+			NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
+			NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
+			desc->plus = 0;
+			goto again;
+		}
+		goto error;
+	}
+	SetPageUptodate(page);
+	NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
+	/* Ensure consistent page alignment of the data.
+	 * Note: assumes we have exclusive access to this mapping either
+	 *	 throught inode->i_sem or some other mechanism.
+	 */
+	if (page->index == 0) {
+		invalidate_inode_pages(inode->i_mapping);
+		NFS_I(inode)->readdir_timestamp = timestamp;
+	}
+	unlock_page(page);
+	return 0;
+ error:
+	SetPageError(page);
+	unlock_page(page);
+	nfs_zap_caches(inode);
+	desc->error = error;
+	return -EIO;
+}
+
+static inline
+int dir_decode(nfs_readdir_descriptor_t *desc)
+{
+	u32	*p = desc->ptr;
+	p = desc->decode(p, desc->entry, desc->plus);
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+	desc->ptr = p;
+	return 0;
+}
+
+static inline
+void dir_page_release(nfs_readdir_descriptor_t *desc)
+{
+	kunmap(desc->page);
+	page_cache_release(desc->page);
+	desc->page = NULL;
+	desc->ptr = NULL;
+}
+
+/*
+ * Given a pointer to a buffer that has already been filled by a call
+ * to readdir, find the next entry.
+ *
+ * If the end of the buffer has been reached, return -EAGAIN, if not,
+ * return the offset within the buffer of the next entry to be
+ * read.
+ */
+static inline
+int find_dirent(nfs_readdir_descriptor_t *desc, struct page *page)
+{
+	struct nfs_entry *entry = desc->entry;
+	int		loop_count = 0,
+			status;
+
+	while((status = dir_decode(desc)) == 0) {
+		dfprintk(VFS, "NFS: found cookie %Lu\n", (long long)entry->cookie);
+		if (entry->prev_cookie == desc->target)
+			break;
+		if (loop_count++ > 200) {
+			loop_count = 0;
+			schedule();
+		}
+	}
+	dfprintk(VFS, "NFS: find_dirent() returns %d\n", status);
+	return status;
+}
+
+/*
+ * Find the given page, and call find_dirent() in order to try to
+ * return the next entry.
+ */
+static inline
+int find_dirent_page(nfs_readdir_descriptor_t *desc)
+{
+	struct inode	*inode = desc->file->f_dentry->d_inode;
+	struct page	*page;
+	int		status;
+
+	dfprintk(VFS, "NFS: find_dirent_page() searching directory page %ld\n", desc->page_index);
+
+	page = read_cache_page(inode->i_mapping, desc->page_index,
+			       (filler_t *)nfs_readdir_filler, desc);
+	if (IS_ERR(page)) {
+		status = PTR_ERR(page);
+		goto out;
+	}
+	if (!PageUptodate(page))
+		goto read_error;
+
+	/* NOTE: Someone else may have changed the READDIRPLUS flag */
+	desc->page = page;
+	desc->ptr = kmap(page);		/* matching kunmap in nfs_do_filldir */
+	status = find_dirent(desc, page);
+	if (status < 0)
+		dir_page_release(desc);
+ out:
+	dfprintk(VFS, "NFS: find_dirent_page() returns %d\n", status);
+	return status;
+ read_error:
+	page_cache_release(page);
+	return -EIO;
+}
+
+/*
+ * Recurse through the page cache pages, and return a
+ * filled nfs_entry structure of the next directory entry if possible.
+ *
+ * The target for the search is 'desc->target'.
+ */
+static inline
+int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
+{
+	int		loop_count = 0;
+	int		res;
+
+	dfprintk(VFS, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", (long long)desc->target);
+	for (;;) {
+		res = find_dirent_page(desc);
+		if (res != -EAGAIN)
+			break;
+		/* Align to beginning of next page */
+		desc->page_index ++;
+		if (loop_count++ > 200) {
+			loop_count = 0;
+			schedule();
+		}
+	}
+	dfprintk(VFS, "NFS: readdir_search_pagecache() returned %d\n", res);
+	return res;
+}
+
+static inline unsigned int dt_type(struct inode *inode)
+{
+	return (inode->i_mode >> 12) & 15;
+}
+
+static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc);
+
+/*
+ * Once we've found the start of the dirent within a page: fill 'er up...
+ */
+static 
+int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
+		   filldir_t filldir)
+{
+	struct file	*file = desc->file;
+	struct nfs_entry *entry = desc->entry;
+	struct dentry	*dentry = NULL;
+	unsigned long	fileid;
+	int		loop_count = 0,
+			res;
+
+	dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (long long)desc->target);
+
+	for(;;) {
+		unsigned d_type = DT_UNKNOWN;
+		/* Note: entry->prev_cookie contains the cookie for
+		 *	 retrieving the current dirent on the server */
+		fileid = nfs_fileid_to_ino_t(entry->ino);
+
+		/* Get a dentry if we have one */
+		if (dentry != NULL)
+			dput(dentry);
+		dentry = nfs_readdir_lookup(desc);
+
+		/* Use readdirplus info */
+		if (dentry != NULL && dentry->d_inode != NULL) {
+			d_type = dt_type(dentry->d_inode);
+			fileid = dentry->d_inode->i_ino;
+		}
+
+		res = filldir(dirent, entry->name, entry->len, 
+			      entry->prev_cookie, fileid, d_type);
+		if (res < 0)
+			break;
+		file->f_pos = desc->target = entry->cookie;
+		if (dir_decode(desc) != 0) {
+			desc->page_index ++;
+			break;
+		}
+		if (loop_count++ > 200) {
+			loop_count = 0;
+			schedule();
+		}
+	}
+	dir_page_release(desc);
+	if (dentry != NULL)
+		dput(dentry);
+	dfprintk(VFS, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (long long)desc->target, res);
+	return res;
+}
+
+/*
+ * If we cannot find a cookie in our cache, we suspect that this is
+ * because it points to a deleted file, so we ask the server to return
+ * whatever it thinks is the next entry. We then feed this to filldir.
+ * If all goes well, we should then be able to find our way round the
+ * cache on the next call to readdir_search_pagecache();
+ *
+ * NOTE: we cannot add the anonymous page to the pagecache because
+ *	 the data it contains might not be page aligned. Besides,
+ *	 we should already have a complete representation of the
+ *	 directory in the page cache by the time we get here.
+ */
+static inline
+int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
+		     filldir_t filldir)
+{
+	struct file	*file = desc->file;
+	struct inode	*inode = file->f_dentry->d_inode;
+	struct rpc_cred	*cred = nfs_file_cred(file);
+	struct page	*page = NULL;
+	int		status;
+
+	dfprintk(VFS, "NFS: uncached_readdir() searching for cookie %Lu\n", (long long)desc->target);
+
+	page = alloc_page(GFP_HIGHUSER);
+	if (!page) {
+		status = -ENOMEM;
+		goto out;
+	}
+	desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->target,
+						page,
+						NFS_SERVER(inode)->dtsize,
+						desc->plus);
+	NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
+	desc->page = page;
+	desc->ptr = kmap(page);		/* matching kunmap in nfs_do_filldir */
+	if (desc->error >= 0) {
+		if ((status = dir_decode(desc)) == 0)
+			desc->entry->prev_cookie = desc->target;
+	} else
+		status = -EIO;
+	if (status < 0)
+		goto out_release;
+
+	status = nfs_do_filldir(desc, dirent, filldir);
+
+	/* Reset read descriptor so it searches the page cache from
+	 * the start upon the next call to readdir_search_pagecache() */
+	desc->page_index = 0;
+	desc->entry->cookie = desc->entry->prev_cookie = 0;
+	desc->entry->eof = 0;
+ out:
+	dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status);
+	return status;
+ out_release:
+	dir_page_release(desc);
+	goto out;
+}
+
+/* The file offset position is now represented as a true offset into the
+ * page cache as is the case in most of the other filesystems.
+ */
+static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+	struct dentry	*dentry = filp->f_dentry;
+	struct inode	*inode = dentry->d_inode;
+	nfs_readdir_descriptor_t my_desc,
+			*desc = &my_desc;
+	struct nfs_entry my_entry;
+	struct nfs_fh	 fh;
+	struct nfs_fattr fattr;
+	long		res;
+
+	lock_kernel();
+
+	res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
+	if (res < 0) {
+		unlock_kernel();
+		return res;
+	}
+
+	/*
+	 * filp->f_pos points to the file offset in the page cache.
+	 * but if the cache has meanwhile been zapped, we need to
+	 * read from the last dirent to revalidate f_pos
+	 * itself.
+	 */
+	memset(desc, 0, sizeof(*desc));
+
+	desc->file = filp;
+	desc->target = filp->f_pos;
+	desc->decode = NFS_PROTO(inode)->decode_dirent;
+	desc->plus = NFS_USE_READDIRPLUS(inode);
+
+	my_entry.cookie = my_entry.prev_cookie = 0;
+	my_entry.eof = 0;
+	my_entry.fh = &fh;
+	my_entry.fattr = &fattr;
+	desc->entry = &my_entry;
+
+	while(!desc->entry->eof) {
+		res = readdir_search_pagecache(desc);
+		if (res == -EBADCOOKIE) {
+			/* This means either end of directory */
+			if (desc->entry->cookie != desc->target) {
+				/* Or that the server has 'lost' a cookie */
+				res = uncached_readdir(desc, dirent, filldir);
+				if (res >= 0)
+					continue;
+			}
+			res = 0;
+			break;
+		}
+		if (res == -ETOOSMALL && desc->plus) {
+			NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
+			nfs_zap_caches(inode);
+			desc->plus = 0;
+			desc->entry->eof = 0;
+			continue;
+		}
+		if (res < 0)
+			break;
+
+		res = nfs_do_filldir(desc, dirent, filldir);
+		if (res < 0) {
+			res = 0;
+			break;
+		}
+	}
+	unlock_kernel();
+	if (desc->error < 0)
+		return desc->error;
+	if (res < 0)
+		return res;
+	return 0;
+}
+
+/*
+ * All directory operations under NFS are synchronous, so fsync()
+ * is a dummy operation.
+ */
+int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync)
+{
+	return 0;
+}
+
+/*
+ * A check for whether or not the parent directory has changed.
+ * In the case it has, we assume that the dentries are untrustworthy
+ * and may need to be looked up again.
+ */
+static inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
+{
+	if (IS_ROOT(dentry))
+		return 1;
+	if ((NFS_FLAGS(dir) & NFS_INO_INVALID_ATTR) != 0
+			|| nfs_attribute_timeout(dir))
+		return 0;
+	return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata);
+}
+
+static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
+{
+	dentry->d_fsdata = (void *)verf;
+}
+
+/*
+ * Whenever an NFS operation succeeds, we know that the dentry
+ * is valid, so we update the revalidation timestamp.
+ */
+static inline void nfs_renew_times(struct dentry * dentry)
+{
+	dentry->d_time = jiffies;
+}
+
+static inline
+int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
+{
+	struct nfs_server *server = NFS_SERVER(inode);
+
+	if (nd != NULL) {
+		int ndflags = nd->flags;
+		/* VFS wants an on-the-wire revalidation */
+		if (ndflags & LOOKUP_REVAL)
+			goto out_force;
+		/* This is an open(2) */
+		if ((ndflags & LOOKUP_OPEN) &&
+				!(ndflags & LOOKUP_CONTINUE) &&
+				!(server->flags & NFS_MOUNT_NOCTO))
+			goto out_force;
+	}
+	return nfs_revalidate_inode(server, inode);
+out_force:
+	return __nfs_revalidate_inode(server, inode);
+}
+
+/*
+ * We judge how long we want to trust negative
+ * dentries by looking at the parent inode mtime.
+ *
+ * If parent mtime has changed, we revalidate, else we wait for a
+ * period corresponding to the parent's attribute cache timeout value.
+ */
+static inline
+int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
+		       struct nameidata *nd)
+{
+	int ndflags = 0;
+
+	if (nd)
+		ndflags = nd->flags;
+	/* Don't revalidate a negative dentry if we're creating a new file */
+	if ((ndflags & LOOKUP_CREATE) && !(ndflags & LOOKUP_CONTINUE))
+		return 0;
+	return !nfs_check_verifier(dir, dentry);
+}
+
+/*
+ * This is called every time the dcache has a lookup hit,
+ * and we should check whether we can really trust that
+ * lookup.
+ *
+ * NOTE! The hit can be a negative hit too, don't assume
+ * we have an inode!
+ *
+ * If the parent directory is seen to have changed, we throw out the
+ * cached dentry and do a new lookup.
+ */
+static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
+{
+	struct inode *dir;
+	struct inode *inode;
+	struct dentry *parent;
+	int error;
+	struct nfs_fh fhandle;
+	struct nfs_fattr fattr;
+	unsigned long verifier;
+
+	parent = dget_parent(dentry);
+	lock_kernel();
+	dir = parent->d_inode;
+	inode = dentry->d_inode;
+
+	if (!inode) {
+		if (nfs_neg_need_reval(dir, dentry, nd))
+			goto out_bad;
+		goto out_valid;
+	}
+
+	if (is_bad_inode(inode)) {
+		dfprintk(VFS, "nfs_lookup_validate: %s/%s has dud inode\n",
+			dentry->d_parent->d_name.name, dentry->d_name.name);
+		goto out_bad;
+	}
+
+	/* Revalidate parent directory attribute cache */
+	if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
+		goto out_zap_parent;
+
+	/* Force a full look up iff the parent directory has changed */
+	if (nfs_check_verifier(dir, dentry)) {
+		if (nfs_lookup_verify_inode(inode, nd))
+			goto out_zap_parent;
+		goto out_valid;
+	}
+
+	if (NFS_STALE(inode))
+		goto out_bad;
+
+	verifier = nfs_save_change_attribute(dir);
+	error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
+	if (error)
+		goto out_bad;
+	if (nfs_compare_fh(NFS_FH(inode), &fhandle))
+		goto out_bad;
+	if ((error = nfs_refresh_inode(inode, &fattr)) != 0)
+		goto out_bad;
+
+	nfs_renew_times(dentry);
+	nfs_set_verifier(dentry, verifier);
+ out_valid:
+	unlock_kernel();
+	dput(parent);
+	return 1;
+out_zap_parent:
+	nfs_zap_caches(dir);
+ out_bad:
+	NFS_CACHEINV(dir);
+	if (inode && S_ISDIR(inode->i_mode)) {
+		/* Purge readdir caches. */
+		nfs_zap_caches(inode);
+		/* If we have submounts, don't unhash ! */
+		if (have_submounts(dentry))
+			goto out_valid;
+		shrink_dcache_parent(dentry);
+	}
+	d_drop(dentry);
+	unlock_kernel();
+	dput(parent);
+	return 0;
+}
+
+/*
+ * This is called from dput() when d_count is going to 0.
+ */
+static int nfs_dentry_delete(struct dentry *dentry)
+{
+	dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n",
+		dentry->d_parent->d_name.name, dentry->d_name.name,
+		dentry->d_flags);
+
+	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+		/* Unhash it, so that ->d_iput() would be called */
+		return 1;
+	}
+	if (!(dentry->d_sb->s_flags & MS_ACTIVE)) {
+		/* Unhash it, so that ancestors of killed async unlink
+		 * files will be cleaned up during umount */
+		return 1;
+	}
+	return 0;
+
+}
+
+/*
+ * Called when the dentry loses inode.
+ * We use it to clean up silly-renamed files.
+ */
+static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
+{
+	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+		lock_kernel();
+		inode->i_nlink--;
+		nfs_complete_unlink(dentry);
+		unlock_kernel();
+	}
+	/* When creating a negative dentry, we want to renew d_time */
+	nfs_renew_times(dentry);
+	iput(inode);
+}
+
+struct dentry_operations nfs_dentry_operations = {
+	.d_revalidate	= nfs_lookup_revalidate,
+	.d_delete	= nfs_dentry_delete,
+	.d_iput		= nfs_dentry_iput,
+};
+
+static inline
+int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
+{
+	if (NFS_PROTO(dir)->version == 2)
+		return 0;
+	if (!nd || (nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_CREATE))
+		return 0;
+	return (nd->intent.open.flags & O_EXCL) != 0;
+}
+
+static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
+{
+	struct dentry *res;
+	struct inode *inode = NULL;
+	int error;
+	struct nfs_fh fhandle;
+	struct nfs_fattr fattr;
+
+	dfprintk(VFS, "NFS: lookup(%s/%s)\n",
+		dentry->d_parent->d_name.name, dentry->d_name.name);
+
+	res = ERR_PTR(-ENAMETOOLONG);
+	if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
+		goto out;
+
+	res = ERR_PTR(-ENOMEM);
+	dentry->d_op = NFS_PROTO(dir)->dentry_ops;
+
+	lock_kernel();
+	/* Revalidate parent directory attribute cache */
+	error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
+	if (error < 0) {
+		res = ERR_PTR(error);
+		goto out_unlock;
+	}
+
+	/* If we're doing an exclusive create, optimize away the lookup */
+	if (nfs_is_exclusive_create(dir, nd))
+		goto no_entry;
+
+	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;
+	}
+	res = ERR_PTR(-EACCES);
+	inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
+	if (!inode)
+		goto out_unlock;
+no_entry:
+	res = d_add_unique(dentry, inode);
+	if (res != NULL)
+		dentry = res;
+	nfs_renew_times(dentry);
+	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+out_unlock:
+	unlock_kernel();
+out:
+	return res;
+}
+
+#ifdef CONFIG_NFS_V4
+static int nfs_open_revalidate(struct dentry *, struct nameidata *);
+
+struct dentry_operations nfs4_dentry_operations = {
+	.d_revalidate	= nfs_open_revalidate,
+	.d_delete	= nfs_dentry_delete,
+	.d_iput		= nfs_dentry_iput,
+};
+
+static int is_atomic_open(struct inode *dir, struct nameidata *nd)
+{
+	if (!nd)
+		return 0;
+	/* Check that we are indeed trying to open this file */
+	if ((nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_OPEN))
+		return 0;
+	/* NFS does not (yet) have a stateful open for directories */
+	if (nd->flags & LOOKUP_DIRECTORY)
+		return 0;
+	/* Are we trying to write to a read only partition? */
+	if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE)))
+		return 0;
+	return 1;
+}
+
+static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+	struct dentry *res = NULL;
+	struct inode *inode = NULL;
+	int error;
+
+	/* Check that we are indeed trying to open this file */
+	if (!is_atomic_open(dir, nd))
+		goto no_open;
+
+	if (dentry->d_name.len > NFS_SERVER(dir)->namelen) {
+		res = ERR_PTR(-ENAMETOOLONG);
+		goto out;
+	}
+	dentry->d_op = NFS_PROTO(dir)->dentry_ops;
+
+	/* Let vfs_create() deal with O_EXCL */
+	if (nd->intent.open.flags & O_EXCL)
+		goto no_entry;
+
+	/* Open the file on the server */
+	lock_kernel();
+	/* Revalidate parent directory attribute cache */
+	error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
+	if (error < 0) {
+		res = ERR_PTR(error);
+		goto out;
+	}
+
+	if (nd->intent.open.flags & O_CREAT) {
+		nfs_begin_data_update(dir);
+		inode = nfs4_atomic_open(dir, dentry, nd);
+		nfs_end_data_update(dir);
+	} else
+		inode = nfs4_atomic_open(dir, dentry, nd);
+	unlock_kernel();
+	if (IS_ERR(inode)) {
+		error = PTR_ERR(inode);
+		switch (error) {
+			/* Make a negative dentry */
+			case -ENOENT:
+				inode = NULL;
+				break;
+			/* This turned out not to be a regular file */
+			case -ELOOP:
+				if (!(nd->intent.open.flags & O_NOFOLLOW))
+					goto no_open;
+			/* case -EISDIR: */
+			/* case -EINVAL: */
+			default:
+				res = ERR_PTR(error);
+				goto out;
+		}
+	}
+no_entry:
+	res = d_add_unique(dentry, inode);
+	if (res != NULL)
+		dentry = res;
+	nfs_renew_times(dentry);
+	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+out:
+	return res;
+no_open:
+	return nfs_lookup(dir, dentry, nd);
+}
+
+static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+	struct dentry *parent = NULL;
+	struct inode *inode = dentry->d_inode;
+	struct inode *dir;
+	unsigned long verifier;
+	int openflags, ret = 0;
+
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	if (!is_atomic_open(dir, nd))
+		goto no_open;
+	/* We can't create new files in nfs_open_revalidate(), so we
+	 * optimize away revalidation of negative dentries.
+	 */
+	if (inode == NULL)
+		goto out;
+	/* NFS only supports OPEN on regular files */
+	if (!S_ISREG(inode->i_mode))
+		goto no_open;
+	openflags = nd->intent.open.flags;
+	/* We cannot do exclusive creation on a positive dentry */
+	if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
+		goto no_open;
+	/* We can't create new files, or truncate existing ones here */
+	openflags &= ~(O_CREAT|O_TRUNC);
+
+	/*
+	 * Note: we're not holding inode->i_sem and so may be racing with
+	 * operations that change the directory. We therefore save the
+	 * change attribute *before* we do the RPC call.
+	 */
+	lock_kernel();
+	verifier = nfs_save_change_attribute(dir);
+	ret = nfs4_open_revalidate(dir, dentry, openflags);
+	if (!ret)
+		nfs_set_verifier(dentry, verifier);
+	unlock_kernel();
+out:
+	dput(parent);
+	if (!ret)
+		d_drop(dentry);
+	return ret;
+no_open:
+	dput(parent);
+	if (inode != NULL && nfs_have_delegation(inode, FMODE_READ))
+		return 1;
+	return nfs_lookup_revalidate(dentry, nd);
+}
+#endif /* CONFIG_NFSV4 */
+
+static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
+{
+	struct dentry *parent = desc->file->f_dentry;
+	struct inode *dir = parent->d_inode;
+	struct nfs_entry *entry = desc->entry;
+	struct dentry *dentry, *alias;
+	struct qstr name = {
+		.name = entry->name,
+		.len = entry->len,
+	};
+	struct inode *inode;
+
+	switch (name.len) {
+		case 2:
+			if (name.name[0] == '.' && name.name[1] == '.')
+				return dget_parent(parent);
+			break;
+		case 1:
+			if (name.name[0] == '.')
+				return dget(parent);
+	}
+	name.hash = full_name_hash(name.name, name.len);
+	dentry = d_lookup(parent, &name);
+	if (dentry != NULL)
+		return dentry;
+	if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR))
+		return NULL;
+	/* Note: caller is already holding the dir->i_sem! */
+	dentry = d_alloc(parent, &name);
+	if (dentry == NULL)
+		return NULL;
+	dentry->d_op = NFS_PROTO(dir)->dentry_ops;
+	inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr);
+	if (!inode) {
+		dput(dentry);
+		return NULL;
+	}
+	alias = d_add_unique(dentry, inode);
+	if (alias != NULL) {
+		dput(dentry);
+		dentry = alias;
+	}
+	nfs_renew_times(dentry);
+	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+	return dentry;
+}
+
+/*
+ * Code common to create, mkdir, and mknod.
+ */
+int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
+				struct nfs_fattr *fattr)
+{
+	struct inode *inode;
+	int error = -EACCES;
+
+	/* We may have been initialized further down */
+	if (dentry->d_inode)
+		return 0;
+	if (fhandle->size == 0) {
+		struct inode *dir = dentry->d_parent->d_inode;
+		error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
+		if (error)
+			goto out_err;
+	}
+	if (!(fattr->valid & NFS_ATTR_FATTR)) {
+		struct nfs_server *server = NFS_SB(dentry->d_sb);
+		error = server->rpc_ops->getattr(server, fhandle, fattr);
+		if (error < 0)
+			goto out_err;
+	}
+	error = -ENOMEM;
+	inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
+	if (inode == NULL)
+		goto out_err;
+	d_instantiate(dentry, inode);
+	return 0;
+out_err:
+	d_drop(dentry);
+	return error;
+}
+
+/*
+ * Following a failed create operation, we drop the dentry rather
+ * than retain a negative dentry. This avoids a problem in the event
+ * that the operation succeeded on the server, but an error in the
+ * reply path made it appear to have failed.
+ */
+static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
+		struct nameidata *nd)
+{
+	struct iattr attr;
+	int error;
+	int open_flags = 0;
+
+	dfprintk(VFS, "NFS: create(%s/%ld, %s\n", dir->i_sb->s_id, 
+		dir->i_ino, dentry->d_name.name);
+
+	attr.ia_mode = mode;
+	attr.ia_valid = ATTR_MODE;
+
+	if (nd && (nd->flags & LOOKUP_CREATE))
+		open_flags = nd->intent.open.flags;
+
+	lock_kernel();
+	nfs_begin_data_update(dir);
+	error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
+	nfs_end_data_update(dir);
+	if (error != 0)
+		goto out_err;
+	nfs_renew_times(dentry);
+	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+	unlock_kernel();
+	return 0;
+out_err:
+	unlock_kernel();
+	d_drop(dentry);
+	return error;
+}
+
+/*
+ * See comments for nfs_proc_create regarding failed operations.
+ */
+static int
+nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
+{
+	struct iattr attr;
+	int status;
+
+	dfprintk(VFS, "NFS: mknod(%s/%ld, %s\n", dir->i_sb->s_id,
+		dir->i_ino, dentry->d_name.name);
+
+	if (!new_valid_dev(rdev))
+		return -EINVAL;
+
+	attr.ia_mode = mode;
+	attr.ia_valid = ATTR_MODE;
+
+	lock_kernel();
+	nfs_begin_data_update(dir);
+	status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
+	nfs_end_data_update(dir);
+	if (status != 0)
+		goto out_err;
+	nfs_renew_times(dentry);
+	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+	unlock_kernel();
+	return 0;
+out_err:
+	unlock_kernel();
+	d_drop(dentry);
+	return status;
+}
+
+/*
+ * See comments for nfs_proc_create regarding failed operations.
+ */
+static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	struct iattr attr;
+	int error;
+
+	dfprintk(VFS, "NFS: mkdir(%s/%ld, %s\n", dir->i_sb->s_id,
+		dir->i_ino, dentry->d_name.name);
+
+	attr.ia_valid = ATTR_MODE;
+	attr.ia_mode = mode | S_IFDIR;
+
+	lock_kernel();
+	nfs_begin_data_update(dir);
+	error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
+	nfs_end_data_update(dir);
+	if (error != 0)
+		goto out_err;
+	nfs_renew_times(dentry);
+	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+	unlock_kernel();
+	return 0;
+out_err:
+	d_drop(dentry);
+	unlock_kernel();
+	return error;
+}
+
+static int nfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	int error;
+
+	dfprintk(VFS, "NFS: rmdir(%s/%ld, %s\n", dir->i_sb->s_id,
+		dir->i_ino, dentry->d_name.name);
+
+	lock_kernel();
+	nfs_begin_data_update(dir);
+	error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
+	/* Ensure the VFS deletes this inode */
+	if (error == 0 && dentry->d_inode != NULL)
+		dentry->d_inode->i_nlink = 0;
+	nfs_end_data_update(dir);
+	unlock_kernel();
+
+	return error;
+}
+
+static int nfs_sillyrename(struct inode *dir, struct dentry *dentry)
+{
+	static unsigned int sillycounter;
+	const int      i_inosize  = sizeof(dir->i_ino)*2;
+	const int      countersize = sizeof(sillycounter)*2;
+	const int      slen       = sizeof(".nfs") + i_inosize + countersize - 1;
+	char           silly[slen+1];
+	struct qstr    qsilly;
+	struct dentry *sdentry;
+	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));
+
+#ifdef NFS_PARANOIA
+if (!dentry->d_inode)
+printk("NFS: silly-renaming %s/%s, negative dentry??\n",
+dentry->d_parent->d_name.name, dentry->d_name.name);
+#endif
+	/*
+	 * 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",
+		i_inosize, i_inosize, dentry->d_inode->i_ino);
+
+	sdentry = NULL;
+	do {
+		char *suffix = silly + slen - countersize;
+
+		dput(sdentry);
+		sillycounter++;
+		sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
+
+		dfprintk(VFS, "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 */
+
+	qsilly.name = silly;
+	qsilly.len  = strlen(silly);
+	nfs_begin_data_update(dir);
+	if (dentry->d_inode) {
+		nfs_begin_data_update(dentry->d_inode);
+		error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
+				dir, &qsilly);
+		nfs_end_data_update(dentry->d_inode);
+	} else
+		error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
+				dir, &qsilly);
+	nfs_end_data_update(dir);
+	if (!error) {
+		nfs_renew_times(dentry);
+		nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+		d_move(dentry, sdentry);
+		error = nfs_async_unlink(dentry);
+ 		/* If we return 0 we don't unlink */
+	}
+	dput(sdentry);
+out:
+	return error;
+}
+
+/*
+ * Remove a file after making sure there are no pending writes,
+ * and after checking that the file has only one user. 
+ *
+ * We invalidate the attribute cache and free the inode prior to the operation
+ * to avoid possible races if the server reuses the inode.
+ */
+static int nfs_safe_remove(struct dentry *dentry)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	struct inode *inode = dentry->d_inode;
+	int error = -EBUSY;
+		
+	dfprintk(VFS, "NFS: safe_remove(%s/%s)\n",
+		dentry->d_parent->d_name.name, dentry->d_name.name);
+
+	/* If the dentry was sillyrenamed, we simply call d_delete() */
+	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+		error = 0;
+		goto out;
+	}
+
+	nfs_begin_data_update(dir);
+	if (inode != NULL) {
+		nfs_begin_data_update(inode);
+		error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
+		/* The VFS may want to delete this inode */
+		if (error == 0)
+			inode->i_nlink--;
+		nfs_end_data_update(inode);
+	} else
+		error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
+	nfs_end_data_update(dir);
+out:
+	return error;
+}
+
+/*  We do silly rename. In case sillyrename() returns -EBUSY, the inode
+ *  belongs to an active ".nfs..." file and we return -EBUSY.
+ *
+ *  If sillyrename() returns 0, we do nothing, otherwise we unlink.
+ */
+static int nfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int error;
+	int need_rehash = 0;
+
+	dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id,
+		dir->i_ino, dentry->d_name.name);
+
+	lock_kernel();
+	spin_lock(&dcache_lock);
+	spin_lock(&dentry->d_lock);
+	if (atomic_read(&dentry->d_count) > 1) {
+		spin_unlock(&dentry->d_lock);
+		spin_unlock(&dcache_lock);
+		error = nfs_sillyrename(dir, dentry);
+		unlock_kernel();
+		return error;
+	}
+	if (!d_unhashed(dentry)) {
+		__d_drop(dentry);
+		need_rehash = 1;
+	}
+	spin_unlock(&dentry->d_lock);
+	spin_unlock(&dcache_lock);
+	error = nfs_safe_remove(dentry);
+	if (!error) {
+		nfs_renew_times(dentry);
+		nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+	} else if (need_rehash)
+		d_rehash(dentry);
+	unlock_kernel();
+	return error;
+}
+
+static int
+nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+{
+	struct iattr attr;
+	struct nfs_fattr sym_attr;
+	struct nfs_fh sym_fh;
+	struct qstr qsymname;
+	int error;
+
+	dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
+		dir->i_ino, dentry->d_name.name, symname);
+
+#ifdef NFS_PARANOIA
+if (dentry->d_inode)
+printk("nfs_proc_symlink: %s/%s not negative!\n",
+dentry->d_parent->d_name.name, dentry->d_name.name);
+#endif
+	/*
+	 * Fill in the sattr for the call.
+ 	 * Note: SunOS 4.1.2 crashes if the mode isn't initialized!
+	 */
+	attr.ia_valid = ATTR_MODE;
+	attr.ia_mode = S_IFLNK | S_IRWXUGO;
+
+	qsymname.name = symname;
+	qsymname.len  = strlen(symname);
+
+	lock_kernel();
+	nfs_begin_data_update(dir);
+	error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname,
+					  &attr, &sym_fh, &sym_attr);
+	nfs_end_data_update(dir);
+	if (!error) {
+		error = nfs_instantiate(dentry, &sym_fh, &sym_attr);
+	} else {
+		if (error == -EEXIST)
+			printk("nfs_proc_symlink: %s/%s already exists??\n",
+			       dentry->d_parent->d_name.name, dentry->d_name.name);
+		d_drop(dentry);
+	}
+	unlock_kernel();
+	return error;
+}
+
+static int 
+nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+	int error;
+
+	dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n",
+		old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
+		dentry->d_parent->d_name.name, dentry->d_name.name);
+
+	/*
+	 * Drop the dentry in advance to force a new lookup.
+	 * Since nfs_proc_link doesn't return a file handle,
+	 * we can't use the existing dentry.
+	 */
+	lock_kernel();
+	d_drop(dentry);
+
+	nfs_begin_data_update(dir);
+	nfs_begin_data_update(inode);
+	error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
+	nfs_end_data_update(inode);
+	nfs_end_data_update(dir);
+	unlock_kernel();
+	return error;
+}
+
+/*
+ * RENAME
+ * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
+ * different file handle for the same inode after a rename (e.g. when
+ * moving to a different directory). A fail-safe method to do so would
+ * be to look up old_dir/old_name, create a link to new_dir/new_name and
+ * rename the old file using the sillyrename stuff. This way, the original
+ * file in old_dir will go away when the last process iput()s the inode.
+ *
+ * FIXED.
+ * 
+ * It actually works quite well. One needs to have the possibility for
+ * at least one ".nfs..." file in each directory the file ever gets
+ * moved or linked to which happens automagically with the new
+ * implementation that only depends on the dcache stuff instead of
+ * using the inode layer
+ *
+ * Unfortunately, things are a little more complicated than indicated
+ * above. For a cross-directory move, we want to make sure we can get
+ * rid of the old inode after the operation.  This means there must be
+ * no pending writes (if it's a file), and the use count must be 1.
+ * If these conditions are met, we can drop the dentries before doing
+ * the rename.
+ */
+static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+		      struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct inode *old_inode = old_dentry->d_inode;
+	struct inode *new_inode = new_dentry->d_inode;
+	struct dentry *dentry = NULL, *rehash = NULL;
+	int error = -EBUSY;
+
+	/*
+	 * To prevent any new references to the target during the rename,
+	 * we unhash the dentry and free the inode in advance.
+	 */
+	lock_kernel();
+	if (!d_unhashed(new_dentry)) {
+		d_drop(new_dentry);
+		rehash = new_dentry;
+	}
+
+	dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
+		 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
+		 new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
+		 atomic_read(&new_dentry->d_count));
+
+	/*
+	 * First check whether the target is busy ... we can't
+	 * safely do _any_ rename if the target is in use.
+	 *
+	 * For files, make a copy of the dentry and then do a 
+	 * silly-rename. If the silly-rename succeeds, the
+	 * copied dentry is hashed and becomes the new target.
+	 */
+	if (!new_inode)
+		goto go_ahead;
+	if (S_ISDIR(new_inode->i_mode))
+		goto out;
+	else if (atomic_read(&new_dentry->d_count) > 2) {
+		int err;
+		/* copy the target dentry's name */
+		dentry = d_alloc(new_dentry->d_parent,
+				 &new_dentry->d_name);
+		if (!dentry)
+			goto out;
+
+		/* silly-rename the existing target ... */
+		err = nfs_sillyrename(new_dir, new_dentry);
+		if (!err) {
+			new_dentry = rehash = dentry;
+			new_inode = NULL;
+			/* instantiate the replacement target */
+			d_instantiate(new_dentry, NULL);
+		} else if (atomic_read(&new_dentry->d_count) > 1) {
+		/* dentry still busy? */
+#ifdef NFS_PARANOIA
+			printk("nfs_rename: target %s/%s busy, d_count=%d\n",
+			       new_dentry->d_parent->d_name.name,
+			       new_dentry->d_name.name,
+			       atomic_read(&new_dentry->d_count));
+#endif
+			goto out;
+		}
+	}
+
+go_ahead:
+	/*
+	 * ... prune child dentries and writebacks if needed.
+	 */
+	if (atomic_read(&old_dentry->d_count) > 1) {
+		nfs_wb_all(old_inode);
+		shrink_dcache_parent(old_dentry);
+	}
+
+	if (new_inode)
+		d_delete(new_dentry);
+
+	nfs_begin_data_update(old_dir);
+	nfs_begin_data_update(new_dir);
+	nfs_begin_data_update(old_inode);
+	error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name,
+					   new_dir, &new_dentry->d_name);
+	nfs_end_data_update(old_inode);
+	nfs_end_data_update(new_dir);
+	nfs_end_data_update(old_dir);
+out:
+	if (rehash)
+		d_rehash(rehash);
+	if (!error) {
+		if (!S_ISDIR(old_inode->i_mode))
+			d_move(old_dentry, new_dentry);
+		nfs_renew_times(new_dentry);
+		nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir));
+	}
+
+	/* new dentry created? */
+	if (dentry)
+		dput(dentry);
+	unlock_kernel();
+	return error;
+}
+
+int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
+{
+	struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
+
+	if (cache->cred != cred
+			|| time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
+			|| (NFS_FLAGS(inode) & NFS_INO_INVALID_ACCESS))
+		return -ENOENT;
+	memcpy(res, cache, sizeof(*res));
+	return 0;
+}
+
+void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
+{
+	struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
+
+	if (cache->cred != set->cred) {
+		if (cache->cred)
+			put_rpccred(cache->cred);
+		cache->cred = get_rpccred(set->cred);
+	}
+	NFS_FLAGS(inode) &= ~NFS_INO_INVALID_ACCESS;
+	cache->jiffies = set->jiffies;
+	cache->mask = set->mask;
+}
+
+static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
+{
+	struct nfs_access_entry cache;
+	int status;
+
+	status = nfs_access_get_cached(inode, cred, &cache);
+	if (status == 0)
+		goto out;
+
+	/* Be clever: ask server to check for all possible rights */
+	cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
+	cache.cred = cred;
+	cache.jiffies = jiffies;
+	status = NFS_PROTO(inode)->access(inode, &cache);
+	if (status != 0)
+		return status;
+	nfs_access_add_cache(inode, &cache);
+out:
+	if ((cache.mask & mask) == mask)
+		return 0;
+	return -EACCES;
+}
+
+int nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+	struct rpc_cred *cred;
+	int res = 0;
+
+	if (mask == 0)
+		goto out;
+	/* Is this sys_access() ? */
+	if (nd != NULL && (nd->flags & LOOKUP_ACCESS))
+		goto force_lookup;
+
+	switch (inode->i_mode & S_IFMT) {
+		case S_IFLNK:
+			goto out;
+		case S_IFREG:
+			/* NFSv4 has atomic_open... */
+			if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)
+					&& nd != NULL
+					&& (nd->flags & LOOKUP_OPEN))
+				goto out;
+			break;
+		case S_IFDIR:
+			/*
+			 * Optimize away all write operations, since the server
+			 * will check permissions when we perform the op.
+			 */
+			if ((mask & MAY_WRITE) && !(mask & MAY_READ))
+				goto out;
+	}
+
+force_lookup:
+	lock_kernel();
+
+	if (!NFS_PROTO(inode)->access)
+		goto out_notsup;
+
+	cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
+	if (!IS_ERR(cred)) {
+		res = nfs_do_access(inode, cred, mask);
+		put_rpccred(cred);
+	} else
+		res = PTR_ERR(cred);
+	unlock_kernel();
+out:
+	return res;
+out_notsup:
+	res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
+	if (res == 0)
+		res = generic_permission(inode, mask, NULL);
+	unlock_kernel();
+	return res;
+}
+
+/*
+ * Local variables:
+ *  version-control: t
+ *  kept-new-versions: 5
+ * End:
+ */