dir.c 49.2 KB
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/*
 *  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>

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#include "nfs4_fs.h"
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#include "delegation.h"
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#include "iostat.h"
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#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);
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static loff_t nfs_llseek_dir(struct file *, loff_t, int);
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const struct file_operations nfs_dir_operations = {
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	.llseek		= nfs_llseek_dir,
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	.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,
};

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#ifdef CONFIG_NFS_V3
struct inode_operations nfs3_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,
	.listxattr	= nfs3_listxattr,
	.getxattr	= nfs3_getxattr,
	.setxattr	= nfs3_setxattr,
	.removexattr	= nfs3_removexattr,
};
#endif  /* CONFIG_NFS_V3 */

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#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,
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	.getxattr       = nfs4_getxattr,
	.setxattr       = nfs4_setxattr,
	.listxattr      = nfs4_listxattr,
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};

#endif /* CONFIG_NFS_V4 */

/*
 * Open file
 */
static int
nfs_opendir(struct inode *inode, struct file *filp)
{
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	int res;
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	dfprintk(VFS, "NFS: opendir(%s/%ld)\n",
			inode->i_sb->s_id, inode->i_ino);

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	lock_kernel();
	/* Call generic open code in order to cache credentials */
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	res = nfs_open(inode, filp);
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	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;
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	u64		*dir_cookie;
	loff_t		current_index;
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	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;

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	dfprintk(DIRCACHE, "NFS: %s: reading cookie %Lu into page %lu\n",
			__FUNCTION__, (long long)desc->entry->cookie,
			page->index);
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 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;
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			clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));
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			desc->plus = 0;
			goto again;
		}
		goto error;
	}
	SetPageUptodate(page);
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	spin_lock(&inode->i_lock);
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	NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
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	spin_unlock(&inode->i_lock);
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	/* Ensure consistent page alignment of the data.
	 * Note: assumes we have exclusive access to this mapping either
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	 *	 through inode->i_mutex or some other mechanism.
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	 */
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	if (page->index == 0)
		invalidate_inode_pages2_range(inode->i_mapping, PAGE_CACHE_SIZE, -1);
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	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
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 * to readdir, find the next entry with cookie '*desc->dir_cookie'.
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 *
 * 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
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int find_dirent(nfs_readdir_descriptor_t *desc)
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{
	struct nfs_entry *entry = desc->entry;
	int		loop_count = 0,
			status;

	while((status = dir_decode(desc)) == 0) {
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		dfprintk(DIRCACHE, "NFS: %s: examining cookie %Lu\n",
				__FUNCTION__, (unsigned long long)entry->cookie);
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		if (entry->prev_cookie == *desc->dir_cookie)
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			break;
		if (loop_count++ > 200) {
			loop_count = 0;
			schedule();
		}
	}
	return status;
}

/*
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 * Given a pointer to a buffer that has already been filled by a call
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 * to readdir, find the entry at offset 'desc->file->f_pos'.
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 *
 * 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_index(nfs_readdir_descriptor_t *desc)
{
	struct nfs_entry *entry = desc->entry;
	int		loop_count = 0,
			status;

	for(;;) {
		status = dir_decode(desc);
		if (status)
			break;

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		dfprintk(DIRCACHE, "NFS: found cookie %Lu at index %Ld\n",
				(unsigned long long)entry->cookie, desc->current_index);
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		if (desc->file->f_pos == desc->current_index) {
			*desc->dir_cookie = entry->cookie;
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			break;
		}
		desc->current_index++;
		if (loop_count++ > 200) {
			loop_count = 0;
			schedule();
		}
	}
	return status;
}

/*
 * Find the given page, and call find_dirent() or find_dirent_index in
 * order to try to return the next entry.
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 */
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;

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	dfprintk(DIRCACHE, "NFS: %s: searching page %ld for target %Lu\n",
			__FUNCTION__, desc->page_index,
			(long long) *desc->dir_cookie);
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	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 */
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	if (*desc->dir_cookie != 0)
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		status = find_dirent(desc);
	else
		status = find_dirent_index(desc);
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	if (status < 0)
		dir_page_release(desc);
 out:
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	dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, status);
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	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.
 *
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 * The target for the search is '*desc->dir_cookie' if non-0,
 * 'desc->file->f_pos' otherwise
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 */
static inline
int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
{
	int		loop_count = 0;
	int		res;

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	/* Always search-by-index from the beginning of the cache */
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	if (*desc->dir_cookie == 0) {
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		dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for offset %Ld\n",
				(long long)desc->file->f_pos);
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		desc->page_index = 0;
		desc->entry->cookie = desc->entry->prev_cookie = 0;
		desc->entry->eof = 0;
		desc->current_index = 0;
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	} else
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		dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for cookie %Lu\n",
				(unsigned long long)*desc->dir_cookie);
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	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();
		}
	}
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	dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, res);
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	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;

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	dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n",
			(unsigned long long)entry->cookie);
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	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, 
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			      file->f_pos, fileid, d_type);
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		if (res < 0)
			break;
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		file->f_pos++;
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		*desc->dir_cookie = entry->cookie;
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		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);
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	dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
			(unsigned long long)*desc->dir_cookie, res);
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	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;

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	dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
			(unsigned long long)*desc->dir_cookie);
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	page = alloc_page(GFP_HIGHUSER);
	if (!page) {
		status = -ENOMEM;
		goto out;
	}
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	desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, *desc->dir_cookie,
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						page,
						NFS_SERVER(inode)->dtsize,
						desc->plus);
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	spin_lock(&inode->i_lock);
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	NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
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	spin_unlock(&inode->i_lock);
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	desc->page = page;
	desc->ptr = kmap(page);		/* matching kunmap in nfs_do_filldir */
	if (desc->error >= 0) {
		if ((status = dir_decode(desc)) == 0)
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			desc->entry->prev_cookie = *desc->dir_cookie;
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	} 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:
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	dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
			__FUNCTION__, status);
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	return status;
 out_release:
	dir_page_release(desc);
	goto out;
}

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/* The file offset position represents the dirent entry number.  A
   last cookie cache takes care of the common case of reading the
   whole directory.
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 */
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;

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	dfprintk(VFS, "NFS: readdir(%s/%s) starting at cookie %Lu\n",
			dentry->d_parent->d_name.name, dentry->d_name.name,
			(long long)filp->f_pos);
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	nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);

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	lock_kernel();

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	res = nfs_revalidate_mapping(inode, filp->f_mapping);
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	if (res < 0) {
		unlock_kernel();
		return res;
	}

	/*
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	 * filp->f_pos points to the dirent entry number.
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	 * *desc->dir_cookie has the cookie for the next entry. We have
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	 * to either find the entry with the appropriate number or
	 * revalidate the cookie.
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	 */
	memset(desc, 0, sizeof(*desc));

	desc->file = filp;
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	desc->dir_cookie = &((struct nfs_open_context *)filp->private_data)->dir_cookie;
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	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;
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	nfs_fattr_init(&fattr);
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	desc->entry = &my_entry;

	while(!desc->entry->eof) {
		res = readdir_search_pagecache(desc);
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		if (res == -EBADCOOKIE) {
			/* This means either end of directory */
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			if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) {
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				/* 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) {
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			clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));
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			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();
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	if (res > 0)
		res = 0;
	dfprintk(VFS, "NFS: readdir(%s/%s) returns %ld\n",
			dentry->d_parent->d_name.name, dentry->d_name.name,
			res);
	return res;
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}

596 597
loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin)
{
598
	mutex_lock(&filp->f_dentry->d_inode->i_mutex);
599 600 601 602 603 604 605 606 607 608 609 610 611 612 613
	switch (origin) {
		case 1:
			offset += filp->f_pos;
		case 0:
			if (offset >= 0)
				break;
		default:
			offset = -EINVAL;
			goto out;
	}
	if (offset != filp->f_pos) {
		filp->f_pos = offset;
		((struct nfs_open_context *)filp->private_data)->dir_cookie = 0;
	}
out:
614
	mutex_unlock(&filp->f_dentry->d_inode->i_mutex);
615 616 617
	return offset;
}

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/*
 * 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)
{
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	dfprintk(VFS, "NFS: fsync_dir(%s/%s) datasync %d\n",
			dentry->d_parent->d_name.name, dentry->d_name.name,
			datasync);

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	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;
640
	if ((NFS_I(dir)->cache_validity & NFS_INO_INVALID_ATTR) != 0
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			|| 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;
}

660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681
/*
 * Return the intent data that applies to this particular path component
 *
 * Note that the current set of intents only apply to the very last
 * component of the path.
 * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT.
 */
static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask)
{
	if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT))
		return 0;
	return nd->flags & mask;
}

/*
 * Inode and filehandle revalidation for lookups.
 *
 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
 * or if the intent information indicates that we're about to open this
 * particular file and the "nocto" mount flag is not set.
 *
 */
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static inline
int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
{
	struct nfs_server *server = NFS_SERVER(inode);

	if (nd != NULL) {
		/* VFS wants an on-the-wire revalidation */
689
		if (nd->flags & LOOKUP_REVAL)
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			goto out_force;
		/* This is an open(2) */
692
		if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 &&
693 694 695
				!(server->flags & NFS_MOUNT_NOCTO) &&
				(S_ISREG(inode->i_mode) ||
				 S_ISDIR(inode->i_mode)))
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			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)
{
	/* Don't revalidate a negative dentry if we're creating a new file */
715
	if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0)
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		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;
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	nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
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	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)) {
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		dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n",
				__FUNCTION__, dentry->d_parent->d_name.name,
				dentry->d_name.name);
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		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);
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	dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n",
			__FUNCTION__, dentry->d_parent->d_name.name,
			dentry->d_name.name);
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	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);
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	dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
			__FUNCTION__, dentry->d_parent->d_name.name,
			dentry->d_name.name);
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	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)
{
841
	nfs_inode_return_delegation(inode);
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	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,
};

859 860 861 862
/*
 * Use intent information to check whether or not we're going to do
 * an O_EXCL create using this path component.
 */
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static inline
int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
{
	if (NFS_PROTO(dir)->version == 2)
		return 0;
868
	if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0)
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		return 0;
	return (nd->intent.open.flags & O_EXCL) != 0;
}

873 874 875 876 877 878 879 880 881 882 883
static inline int nfs_reval_fsid(struct inode *dir,
		struct nfs_fh *fh, struct nfs_fattr *fattr)
{
	struct nfs_server *server = NFS_SERVER(dir);

	if (!nfs_fsid_equal(&server->fsid, &fattr->fsid))
		/* Revalidate fsid on root dir */
		return __nfs_revalidate_inode(server, dir->i_sb->s_root->d_inode);
	return 0;
}

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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);
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	nfs_inc_stats(dir, NFSIOS_VFSLOOKUP);
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	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();

	/* 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;
	}
916 917 918 919 920
	error = nfs_reval_fsid(dir, &fhandle, &fattr);
	if (error < 0) {
		res = ERR_PTR(error);
		goto out_unlock;
	}
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	inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
922 923
	res = (struct dentry *)inode;
	if (IS_ERR(res))
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		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,
};

946 947 948 949
/*
 * Use intent information to determine whether we need to substitute
 * the NFSv4-style stateful OPEN for the LOOKUP call
 */
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static int is_atomic_open(struct inode *dir, struct nameidata *nd)
{
952
	if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0)
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		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;
	int error;

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	dfprintk(VFS, "NFS: atomic_lookup(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);

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	/* 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 */
982 983 984 985
	if (nd->intent.open.flags & O_EXCL) {
		d_add(dentry, NULL);
		goto out;
	}
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	/* 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);
993
		unlock_kernel();
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		goto out;
	}

	if (nd->intent.open.flags & O_CREAT) {
		nfs_begin_data_update(dir);
999
		res = nfs4_atomic_open(dir, dentry, nd);
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		nfs_end_data_update(dir);
	} else
1002
		res = nfs4_atomic_open(dir, dentry, nd);
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	unlock_kernel();
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	if (IS_ERR(res)) {
		error = PTR_ERR(res);
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		switch (error) {
			/* Make a negative dentry */
			case -ENOENT:
1009 1010
				res = NULL;
				goto out;
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			/* This turned out not to be a regular file */
1012 1013 1014
			case -EISDIR:
			case -ENOTDIR:
				goto no_open;
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			case -ELOOP:
				if (!(nd->intent.open.flags & O_NOFOLLOW))
					goto no_open;
			/* case -EINVAL: */
			default:
				goto out;
		}
1022
	} else if (res != NULL)
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		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);

	/*
1060
	 * Note: we're not holding inode->i_mutex and so may be racing with
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	 * 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);
1066
	ret = nfs4_open_revalidate(dir, dentry, openflags, nd);
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	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;
1110
	/* Note: caller is already holding the dir->i_mutex! */
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	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);
1116
	if (IS_ERR(inode)) {
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		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;
	}
	inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
1155 1156
	error = PTR_ERR(inode);
	if (IS_ERR(inode))
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		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;

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	dfprintk(VFS, "NFS: create(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
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	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);
1189
	error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd);
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	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;

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	dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
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	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;

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	dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
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	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;

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	dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
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	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));
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	nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
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#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);

1317 1318 1319
	/* Return delegation in anticipation of the rename */
	nfs_inode_return_delegation(dentry->d_inode);

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	sdentry = NULL;
	do {
		char *suffix = silly + slen - countersize;

		dput(sdentry);
		sillycounter++;
		sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);

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		dfprintk(VFS, "NFS: trying to rename %s to %s\n",
				dentry->d_name.name, silly);
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		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);
1347
		nfs_mark_for_revalidate(dentry->d_inode);
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		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) {
1389
		nfs_inode_return_delegation(inode);
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		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--;
1395
		nfs_mark_for_revalidate(inode);
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		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);

	lock_kernel();
	nfs_begin_data_update(dir);
	nfs_begin_data_update(inode);
	error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
1501 1502 1503 1504
	if (error == 0) {
		atomic_inc(&inode->i_count);
		d_instantiate(dentry, inode);
	}
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	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;
1568 1569 1570 1571 1572
	if (S_ISDIR(new_inode->i_mode)) {
		error = -EISDIR;
		if (!S_ISDIR(old_inode->i_mode))
			goto out;
	} else if (atomic_read(&new_dentry->d_count) > 2) {
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		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;
		}
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	} else
		new_inode->i_nlink--;
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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);
	}
1608
	nfs_inode_return_delegation(old_inode);
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1610 1611
	if (new_inode != NULL) {
		nfs_inode_return_delegation(new_inode);
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		d_delete(new_dentry);
1613
	}
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	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);
1620
	nfs_mark_for_revalidate(old_inode);
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	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;
}

1641 1642 1643 1644
static DEFINE_SPINLOCK(nfs_access_lru_lock);
static LIST_HEAD(nfs_access_lru_list);
static atomic_long_t nfs_access_nr_entries;

1645 1646 1647 1648
static void nfs_access_free_entry(struct nfs_access_entry *entry)
{
	put_rpccred(entry->cred);
	kfree(entry);
1649 1650 1651
	smp_mb__before_atomic_dec();
	atomic_long_dec(&nfs_access_nr_entries);
	smp_mb__after_atomic_dec();
1652 1653 1654
}

static void __nfs_access_zap_cache(struct inode *inode)
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{
1656
	struct nfs_inode *nfsi = NFS_I(inode);
1657 1658 1659 1660 1661 1662 1663 1664
	struct rb_root *root_node = &nfsi->access_cache;
	struct rb_node *n, *dispose = NULL;
	struct nfs_access_entry *entry;

	/* Unhook entries from the cache */
	while ((n = rb_first(root_node)) != NULL) {
		entry = rb_entry(n, struct nfs_access_entry, rb_node);
		rb_erase(n, root_node);
1665
		list_del(&entry->lru);
1666 1667 1668 1669 1670
		n->rb_left = dispose;
		dispose = n;
	}
	nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
	spin_unlock(&inode->i_lock);
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1672 1673 1674 1675 1676 1677
	/* Now kill them all! */
	while (dispose != NULL) {
		n = dispose;
		dispose = n->rb_left;
		nfs_access_free_entry(rb_entry(n, struct nfs_access_entry, rb_node));
	}
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}

1680
void nfs_access_zap_cache(struct inode *inode)
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{
1682 1683 1684 1685 1686 1687 1688
	/* Remove from global LRU init */
	if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) {
		spin_lock(&nfs_access_lru_lock);
		list_del_init(&NFS_I(inode)->access_cache_inode_lru);
		spin_unlock(&nfs_access_lru_lock);
	}

1689 1690 1691 1692
	spin_lock(&inode->i_lock);
	/* This will release the spinlock */
	__nfs_access_zap_cache(inode);
}
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1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707
static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred)
{
	struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
	struct nfs_access_entry *entry;

	while (n != NULL) {
		entry = rb_entry(n, struct nfs_access_entry, rb_node);

		if (cred < entry->cred)
			n = n->rb_left;
		else if (cred > entry->cred)
			n = n->rb_right;
		else
			return entry;
L
Linus Torvalds 已提交
1708
	}
1709 1710 1711 1712 1713 1714 1715 1716 1717
	return NULL;
}

int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_access_entry *cache;
	int err = -ENOENT;

1718
	spin_lock(&inode->i_lock);
1719 1720 1721 1722 1723 1724 1725 1726 1727 1728
	if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
		goto out_zap;
	cache = nfs_access_search_rbtree(inode, cred);
	if (cache == NULL)
		goto out;
	if (time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)))
		goto out_stale;
	res->jiffies = cache->jiffies;
	res->cred = cache->cred;
	res->mask = cache->mask;
1729
	list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru);
1730 1731 1732 1733 1734 1735
	err = 0;
out:
	spin_unlock(&inode->i_lock);
	return err;
out_stale:
	rb_erase(&cache->rb_node, &nfsi->access_cache);
1736
	list_del(&cache->lru);
1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747
	spin_unlock(&inode->i_lock);
	nfs_access_free_entry(cache);
	return -ENOENT;
out_zap:
	/* This will release the spinlock */
	__nfs_access_zap_cache(inode);
	return -ENOENT;
}

static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set)
{
1748 1749
	struct nfs_inode *nfsi = NFS_I(inode);
	struct rb_root *root_node = &nfsi->access_cache;
1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767
	struct rb_node **p = &root_node->rb_node;
	struct rb_node *parent = NULL;
	struct nfs_access_entry *entry;

	spin_lock(&inode->i_lock);
	while (*p != NULL) {
		parent = *p;
		entry = rb_entry(parent, struct nfs_access_entry, rb_node);

		if (set->cred < entry->cred)
			p = &parent->rb_left;
		else if (set->cred > entry->cred)
			p = &parent->rb_right;
		else
			goto found;
	}
	rb_link_node(&set->rb_node, parent, p);
	rb_insert_color(&set->rb_node, root_node);
1768
	list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
1769
	spin_unlock(&inode->i_lock);
1770 1771 1772
	return;
found:
	rb_replace_node(parent, &set->rb_node, root_node);
1773 1774
	list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
	list_del(&entry->lru);
1775 1776 1777 1778 1779 1780 1781 1782 1783 1784
	spin_unlock(&inode->i_lock);
	nfs_access_free_entry(entry);
}

void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
{
	struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL);
	if (cache == NULL)
		return;
	RB_CLEAR_NODE(&cache->rb_node);
L
Linus Torvalds 已提交
1785
	cache->jiffies = set->jiffies;
1786
	cache->cred = get_rpccred(set->cred);
L
Linus Torvalds 已提交
1787
	cache->mask = set->mask;
1788 1789

	nfs_access_add_rbtree(inode, cache);
1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801

	/* Update accounting */
	smp_mb__before_atomic_inc();
	atomic_long_inc(&nfs_access_nr_entries);
	smp_mb__after_atomic_inc();

	/* Add inode to global LRU list */
	if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) {
		spin_lock(&nfs_access_lru_lock);
		list_add_tail(&NFS_I(inode)->access_cache_inode_lru, &nfs_access_lru_list);
		spin_unlock(&nfs_access_lru_lock);
	}
L
Linus Torvalds 已提交
1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831
}

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;

C
Chuck Lever 已提交
1832 1833
	nfs_inc_stats(inode, NFSIOS_VFSACCESS);

L
Linus Torvalds 已提交
1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872
	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:
C
Chuck Lever 已提交
1873 1874
	dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n",
		inode->i_sb->s_id, inode->i_ino, mask, res);
L
Linus Torvalds 已提交
1875 1876 1877 1878 1879 1880
	return res;
out_notsup:
	res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
	if (res == 0)
		res = generic_permission(inode, mask, NULL);
	unlock_kernel();
C
Chuck Lever 已提交
1881
	goto out;
L
Linus Torvalds 已提交
1882 1883 1884 1885 1886 1887 1888 1889
}

/*
 * Local variables:
 *  version-control: t
 *  kept-new-versions: 5
 * End:
 */