/* dir.c: AFS filesystem directory handling
   *
   * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/fs.h>
  #include <linux/namei.h>
  #include <linux/pagemap.h>
  #include <linux/ctype.h>
  #include <linux/sched.h>
  #include "internal.h"
  
  static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
  				 unsigned int flags);
  static int afs_dir_open(struct inode *inode, struct file *file);
  static int afs_readdir(struct file *file, struct dir_context *ctx);
  static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
  static int afs_d_delete(const struct dentry *dentry);
  static void afs_d_release(struct dentry *dentry);
  static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,
  				  loff_t fpos, u64 ino, unsigned dtype);
  static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  		      bool excl);
  static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
  static int afs_rmdir(struct inode *dir, struct dentry *dentry);
  static int afs_unlink(struct inode *dir, struct dentry *dentry);
  static int afs_link(struct dentry *from, struct inode *dir,
  		    struct dentry *dentry);
  static int afs_symlink(struct inode *dir, struct dentry *dentry,
  		       const char *content);
  static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
  		      struct inode *new_dir, struct dentry *new_dentry);
  
  const struct file_operations afs_dir_file_operations = {
  	.open		= afs_dir_open,
  	.release	= afs_release,
  	.iterate	= afs_readdir,
  	.lock		= afs_lock,
  	.llseek		= generic_file_llseek,
  };
  
  const struct inode_operations afs_dir_inode_operations = {
  	.create		= afs_create,
  	.lookup		= afs_lookup,
  	.link		= afs_link,
  	.unlink		= afs_unlink,
  	.symlink	= afs_symlink,
  	.mkdir		= afs_mkdir,
  	.rmdir		= afs_rmdir,
  	.rename		= afs_rename,
  	.permission	= afs_permission,
  	.getattr	= afs_getattr,
  	.setattr	= afs_setattr,
  };
  
  const struct dentry_operations afs_fs_dentry_operations = {
  	.d_revalidate	= afs_d_revalidate,
  	.d_delete	= afs_d_delete,
  	.d_release	= afs_d_release,
  	.d_automount	= afs_d_automount,
  };
  
  #define AFS_DIR_HASHTBL_SIZE	128
  #define AFS_DIR_DIRENT_SIZE	32
  #define AFS_DIRENT_PER_BLOCK	64
  
  union afs_dirent {
  	struct {
  		uint8_t		valid;
  		uint8_t		unused[1];
  		__be16		hash_next;
  		__be32		vnode;
  		__be32		unique;
  		uint8_t		name[16];
  		uint8_t		overflow[4];	/* if any char of the name (inc
  						 * NUL) reaches here, consume
  						 * the next dirent too */
  	} u;
  	uint8_t	extended_name[32];
  };
  
  /* AFS directory page header (one at the beginning of every 2048-byte chunk) */
  struct afs_dir_pagehdr {
  	__be16		npages;
  	__be16		magic;
  #define AFS_DIR_MAGIC htons(1234)
  	uint8_t		nentries;
  	uint8_t		bitmap[8];
  	uint8_t		pad[19];
  };
  
  /* directory block layout */
  union afs_dir_block {
  
  	struct afs_dir_pagehdr pagehdr;
  
  	struct {
  		struct afs_dir_pagehdr	pagehdr;
  		uint8_t			alloc_ctrs[128];
  		/* dir hash table */
  		uint16_t		hashtable[AFS_DIR_HASHTBL_SIZE];
  	} hdr;
  
  	union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
  };
  
  /* layout on a linux VM page */
  struct afs_dir_page {
  	union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
  };
  
  struct afs_lookup_cookie {
  	struct dir_context ctx;
  	struct afs_fid	fid;
  	struct qstr name;
  	int		found;
  };
  
  /*
   * check that a directory page is valid
   */
  static inline void afs_dir_check_page(struct inode *dir, struct page *page)
  {
  	struct afs_dir_page *dbuf;
  	loff_t latter;
  	int tmp, qty;
  
  #if 0
  	/* check the page count */
  	qty = desc.size / sizeof(dbuf->blocks[0]);
  	if (qty == 0)
  		goto error;
  
  	if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
  		printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu
  ",
  		       __func__, dir->i_ino, qty,
  		       ntohs(dbuf->blocks[0].pagehdr.npages));
  		goto error;
  	}
  #endif
  
  	/* determine how many magic numbers there should be in this page */
  	latter = dir->i_size - page_offset(page);
  	if (latter >= PAGE_SIZE)
  		qty = PAGE_SIZE;
  	else
  		qty = latter;
  	qty /= sizeof(union afs_dir_block);
  
  	/* check them */
  	dbuf = page_address(page);
  	for (tmp = 0; tmp < qty; tmp++) {
  		if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
  			printk("kAFS: %s(%lu): bad magic %d/%d is %04hx
  ",
  			       __func__, dir->i_ino, tmp, qty,
  			       ntohs(dbuf->blocks[tmp].pagehdr.magic));
  			goto error;
  		}
  	}
  
  	SetPageChecked(page);
  	return;
  
  error:
  	SetPageChecked(page);
  	SetPageError(page);
  }
  
  /*
   * discard a page cached in the pagecache
   */
  static inline void afs_dir_put_page(struct page *page)
  {
  	kunmap(page);
  	page_cache_release(page);
  }
  
  /*
   * get a page into the pagecache
   */
  static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
  				     struct key *key)
  {
  	struct page *page;
  	_enter("{%lu},%lu", dir->i_ino, index);
  
  	page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
  	if (!IS_ERR(page)) {
  		kmap(page);
  		if (!PageChecked(page))
  			afs_dir_check_page(dir, page);
  		if (PageError(page))
  			goto fail;
  	}
  	return page;
  
  fail:
  	afs_dir_put_page(page);
  	_leave(" = -EIO");
  	return ERR_PTR(-EIO);
  }
  
  /*
   * open an AFS directory file
   */
  static int afs_dir_open(struct inode *inode, struct file *file)
  {
  	_enter("{%lu}", inode->i_ino);
  
  	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
  	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
  
  	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
  		return -ENOENT;
  
  	return afs_open(inode, file);
  }
  
  /*
   * deal with one block in an AFS directory
   */
  static int afs_dir_iterate_block(struct dir_context *ctx,
  				 union afs_dir_block *block,
  				 unsigned blkoff)
  {
  	union afs_dirent *dire;
  	unsigned offset, next, curr;
  	size_t nlen;
  	int tmp;
  
  	_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
  
  	curr = (ctx->pos - blkoff) / sizeof(union afs_dirent);
  
  	/* walk through the block, an entry at a time */
  	for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
  	     offset < AFS_DIRENT_PER_BLOCK;
  	     offset = next
  	     ) {
  		next = offset + 1;
  
  		/* skip entries marked unused in the bitmap */
  		if (!(block->pagehdr.bitmap[offset / 8] &
  		      (1 << (offset % 8)))) {
  			_debug("ENT[%Zu.%u]: unused",
  			       blkoff / sizeof(union afs_dir_block), offset);
  			if (offset >= curr)
  				ctx->pos = blkoff +
  					next * sizeof(union afs_dirent);
  			continue;
  		}
  
  		/* got a valid entry */
  		dire = &block->dirents[offset];
  		nlen = strnlen(dire->u.name,
  			       sizeof(*block) -
  			       offset * sizeof(union afs_dirent));
  
  		_debug("ENT[%Zu.%u]: %s %Zu \"%s\"",
  		       blkoff / sizeof(union afs_dir_block), offset,
  		       (offset < curr ? "skip" : "fill"),
  		       nlen, dire->u.name);
  
  		/* work out where the next possible entry is */
  		for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
  			if (next >= AFS_DIRENT_PER_BLOCK) {
  				_debug("ENT[%Zu.%u]:"
  				       " %u travelled beyond end dir block"
  				       " (len %u/%Zu)",
  				       blkoff / sizeof(union afs_dir_block),
  				       offset, next, tmp, nlen);
  				return -EIO;
  			}
  			if (!(block->pagehdr.bitmap[next / 8] &
  			      (1 << (next % 8)))) {
  				_debug("ENT[%Zu.%u]:"
  				       " %u unmarked extension (len %u/%Zu)",
  				       blkoff / sizeof(union afs_dir_block),
  				       offset, next, tmp, nlen);
  				return -EIO;
  			}
  
  			_debug("ENT[%Zu.%u]: ext %u/%Zu",
  			       blkoff / sizeof(union afs_dir_block),
  			       next, tmp, nlen);
  			next++;
  		}
  
  		/* skip if starts before the current position */
  		if (offset < curr)
  			continue;
  
  		/* found the next entry */
  		if (!dir_emit(ctx, dire->u.name, nlen,
  			      ntohl(dire->u.vnode),
  			      ctx->actor == afs_lookup_filldir ?
  			      ntohl(dire->u.unique) : DT_UNKNOWN)) {
  			_leave(" = 0 [full]");
  			return 0;
  		}
  
  		ctx->pos = blkoff + next * sizeof(union afs_dirent);
  	}
  
  	_leave(" = 1 [more]");
  	return 1;
  }
  
  /*
   * iterate through the data blob that lists the contents of an AFS directory
   */
  static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
  			   struct key *key)
  {
  	union afs_dir_block *dblock;
  	struct afs_dir_page *dbuf;
  	struct page *page;
  	unsigned blkoff, limit;
  	int ret;
  
  	_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
  
  	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
  		_leave(" = -ESTALE");
  		return -ESTALE;
  	}
  
  	/* round the file position up to the next entry boundary */
  	ctx->pos += sizeof(union afs_dirent) - 1;
  	ctx->pos &= ~(sizeof(union afs_dirent) - 1);
  
  	/* walk through the blocks in sequence */
  	ret = 0;
  	while (ctx->pos < dir->i_size) {
  		blkoff = ctx->pos & ~(sizeof(union afs_dir_block) - 1);
  
  		/* fetch the appropriate page from the directory */
  		page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
  		if (IS_ERR(page)) {
  			ret = PTR_ERR(page);
  			break;
  		}
  
  		limit = blkoff & ~(PAGE_SIZE - 1);
  
  		dbuf = page_address(page);
  
  		/* deal with the individual blocks stashed on this page */
  		do {
  			dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
  					       sizeof(union afs_dir_block)];
  			ret = afs_dir_iterate_block(ctx, dblock, blkoff);
  			if (ret != 1) {
  				afs_dir_put_page(page);
  				goto out;
  			}
  
  			blkoff += sizeof(union afs_dir_block);
  
  		} while (ctx->pos < dir->i_size && blkoff < limit);
  
  		afs_dir_put_page(page);
  		ret = 0;
  	}
  
  out:
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * read an AFS directory
   */
  static int afs_readdir(struct file *file, struct dir_context *ctx)
  {
  	return afs_dir_iterate(file_inode(file), 
  			      ctx, file->private_data);
  }
  
  /*
   * search the directory for a name
   * - if afs_dir_iterate_block() spots this function, it'll pass the FID
   *   uniquifier through dtype
   */
  static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,
  			      loff_t fpos, u64 ino, unsigned dtype)
  {
  	struct afs_lookup_cookie *cookie = _cookie;
  
  	_enter("{%s,%u},%s,%u,,%llu,%u",
  	       cookie->name.name, cookie->name.len, name, nlen,
  	       (unsigned long long) ino, dtype);
  
  	/* insanity checks first */
  	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
  	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
  
  	if (cookie->name.len != nlen ||
  	    memcmp(cookie->name.name, name, nlen) != 0) {
  		_leave(" = 0 [no]");
  		return 0;
  	}
  
  	cookie->fid.vnode = ino;
  	cookie->fid.unique = dtype;
  	cookie->found = 1;
  
  	_leave(" = -1 [found]");
  	return -1;
  }
  
  /*
   * do a lookup in a directory
   * - just returns the FID the dentry name maps to if found
   */
  static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
  			 struct afs_fid *fid, struct key *key)
  {
  	struct afs_super_info *as = dir->i_sb->s_fs_info;
  	struct afs_lookup_cookie cookie = {
  		.ctx.actor = afs_lookup_filldir,
  		.name = dentry->d_name,
  		.fid.vid = as->volume->vid
  	};
  	int ret;
  
  	_enter("{%lu},%p{%s},", dir->i_ino, dentry, dentry->d_name.name);
  
  	/* search the directory */
  	ret = afs_dir_iterate(dir, &cookie.ctx, key);
  	if (ret < 0) {
  		_leave(" = %d [iter]", ret);
  		return ret;
  	}
  
  	ret = -ENOENT;
  	if (!cookie.found) {
  		_leave(" = -ENOENT [not found]");
  		return -ENOENT;
  	}
  
  	*fid = cookie.fid;
  	_leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
  	return 0;
  }
  
  /*
   * Try to auto mount the mountpoint with pseudo directory, if the autocell
   * operation is setted.
   */
  static struct inode *afs_try_auto_mntpt(
  	int ret, struct dentry *dentry, struct inode *dir, struct key *key,
  	struct afs_fid *fid)
  {
  	const char *devname = dentry->d_name.name;
  	struct afs_vnode *vnode = AFS_FS_I(dir);
  	struct inode *inode;
  
  	_enter("%d, %p{%s}, {%x:%u}, %p",
  	       ret, dentry, devname, vnode->fid.vid, vnode->fid.vnode, key);
  
  	if (ret != -ENOENT ||
  	    !test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
  		goto out;
  
  	inode = afs_iget_autocell(dir, devname, strlen(devname), key);
  	if (IS_ERR(inode)) {
  		ret = PTR_ERR(inode);
  		goto out;
  	}
  
  	*fid = AFS_FS_I(inode)->fid;
  	_leave("= %p", inode);
  	return inode;
  
  out:
  	_leave("= %d", ret);
  	return ERR_PTR(ret);
  }
  
  /*
   * look up an entry in a directory
   */
  static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
  				 unsigned int flags)
  {
  	struct afs_vnode *vnode;
  	struct afs_fid fid;
  	struct inode *inode;
  	struct key *key;
  	int ret;
  
  	vnode = AFS_FS_I(dir);
  
  	_enter("{%x:%u},%p{%s},",
  	       vnode->fid.vid, vnode->fid.vnode, dentry, dentry->d_name.name);
  
  	ASSERTCMP(dentry->d_inode, ==, NULL);
  
  	if (dentry->d_name.len >= AFSNAMEMAX) {
  		_leave(" = -ENAMETOOLONG");
  		return ERR_PTR(-ENAMETOOLONG);
  	}
  
  	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
  		_leave(" = -ESTALE");
  		return ERR_PTR(-ESTALE);
  	}
  
  	key = afs_request_key(vnode->volume->cell);
  	if (IS_ERR(key)) {
  		_leave(" = %ld [key]", PTR_ERR(key));
  		return ERR_CAST(key);
  	}
  
  	ret = afs_validate(vnode, key);
  	if (ret < 0) {
  		key_put(key);
  		_leave(" = %d [val]", ret);
  		return ERR_PTR(ret);
  	}
  
  	ret = afs_do_lookup(dir, dentry, &fid, key);
  	if (ret < 0) {
  		inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
  		if (!IS_ERR(inode)) {
  			key_put(key);
  			goto success;
  		}
  
  		ret = PTR_ERR(inode);
  		key_put(key);
  		if (ret == -ENOENT) {
  			d_add(dentry, NULL);
  			_leave(" = NULL [negative]");
  			return NULL;
  		}
  		_leave(" = %d [do]", ret);
  		return ERR_PTR(ret);
  	}
  	dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;
  
  	/* instantiate the dentry */
  	inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL);
  	key_put(key);
  	if (IS_ERR(inode)) {
  		_leave(" = %ld", PTR_ERR(inode));
  		return ERR_CAST(inode);
  	}
  
  success:
  	d_add(dentry, inode);
  	_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
  	       fid.vnode,
  	       fid.unique,
  	       dentry->d_inode->i_ino,
  	       dentry->d_inode->i_generation);
  
  	return NULL;
  }
  
  /*
   * check that a dentry lookup hit has found a valid entry
   * - NOTE! the hit can be a negative hit too, so we can't assume we have an
   *   inode
   */
  static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
  {
  	struct afs_vnode *vnode, *dir;
  	struct afs_fid uninitialized_var(fid);
  	struct dentry *parent;
  	struct key *key;
  	void *dir_version;
  	int ret;
  
  	if (flags & LOOKUP_RCU)
  		return -ECHILD;
  
  	vnode = AFS_FS_I(dentry->d_inode);
  
  	if (dentry->d_inode)
  		_enter("{v={%x:%u} n=%s fl=%lx},",
  		       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
  		       vnode->flags);
  	else
  		_enter("{neg n=%s}", dentry->d_name.name);
  
  	key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
  	if (IS_ERR(key))
  		key = NULL;
  
  	/* lock down the parent dentry so we can peer at it */
  	parent = dget_parent(dentry);
  	dir = AFS_FS_I(parent->d_inode);
  
  	/* validate the parent directory */
  	if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))
  		afs_validate(dir, key);
  
  	if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
  		_debug("%s: parent dir deleted", dentry->d_name.name);
  		goto out_bad;
  	}
  
  	dir_version = (void *) (unsigned long) dir->status.data_version;
  	if (dentry->d_fsdata == dir_version)
  		goto out_valid; /* the dir contents are unchanged */
  
  	_debug("dir modified");
  
  	/* search the directory for this vnode */
  	ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
  	switch (ret) {
  	case 0:
  		/* the filename maps to something */
  		if (!dentry->d_inode)
  			goto out_bad;
  		if (is_bad_inode(dentry->d_inode)) {
  			printk("kAFS: afs_d_revalidate: %s/%s has bad inode
  ",
  			       parent->d_name.name, dentry->d_name.name);
  			goto out_bad;
  		}
  
  		/* if the vnode ID has changed, then the dirent points to a
  		 * different file */
  		if (fid.vnode != vnode->fid.vnode) {
  			_debug("%s: dirent changed [%u != %u]",
  			       dentry->d_name.name, fid.vnode,
  			       vnode->fid.vnode);
  			goto not_found;
  		}
  
  		/* if the vnode ID uniqifier has changed, then the file has
  		 * been deleted and replaced, and the original vnode ID has
  		 * been reused */
  		if (fid.unique != vnode->fid.unique) {
  			_debug("%s: file deleted (uq %u -> %u I:%u)",
  			       dentry->d_name.name, fid.unique,
  			       vnode->fid.unique,
  			       dentry->d_inode->i_generation);
  			spin_lock(&vnode->lock);
  			set_bit(AFS_VNODE_DELETED, &vnode->flags);
  			spin_unlock(&vnode->lock);
  			goto not_found;
  		}
  		goto out_valid;
  
  	case -ENOENT:
  		/* the filename is unknown */
  		_debug("%s: dirent not found", dentry->d_name.name);
  		if (dentry->d_inode)
  			goto not_found;
  		goto out_valid;
  
  	default:
  		_debug("failed to iterate dir %s: %d",
  		       parent->d_name.name, ret);
  		goto out_bad;
  	}
  
  out_valid:
  	dentry->d_fsdata = dir_version;
  out_skip:
  	dput(parent);
  	key_put(key);
  	_leave(" = 1 [valid]");
  	return 1;
  
  	/* the dirent, if it exists, now points to a different vnode */
  not_found:
  	spin_lock(&dentry->d_lock);
  	dentry->d_flags |= DCACHE_NFSFS_RENAMED;
  	spin_unlock(&dentry->d_lock);
  
  out_bad:
  	/* don't unhash if we have submounts */
  	if (check_submounts_and_drop(dentry) != 0)
  		goto out_skip;
  
  	_debug("dropping dentry %s/%s",
  	       parent->d_name.name, dentry->d_name.name);
  	dput(parent);
  	key_put(key);
  
  	_leave(" = 0 [bad]");
  	return 0;
  }
  
  /*
   * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
   * sleep)
   * - called from dput() when d_count is going to 0.
   * - return 1 to request dentry be unhashed, 0 otherwise
   */
  static int afs_d_delete(const struct dentry *dentry)
  {
  	_enter("%s", dentry->d_name.name);
  
  	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
  		goto zap;
  
  	if (dentry->d_inode &&
  	    (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(dentry->d_inode)->flags) ||
  	     test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(dentry->d_inode)->flags)))
  		goto zap;
  
  	_leave(" = 0 [keep]");
  	return 0;
  
  zap:
  	_leave(" = 1 [zap]");
  	return 1;
  }
  
  /*
   * handle dentry release
   */
  static void afs_d_release(struct dentry *dentry)
  {
  	_enter("%s", dentry->d_name.name);
  }
  
  /*
   * create a directory on an AFS filesystem
   */
  static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
  {
  	struct afs_file_status status;
  	struct afs_callback cb;
  	struct afs_server *server;
  	struct afs_vnode *dvnode, *vnode;
  	struct afs_fid fid;
  	struct inode *inode;
  	struct key *key;
  	int ret;
  
  	dvnode = AFS_FS_I(dir);
  
  	_enter("{%x:%u},{%s},%ho",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	mode |= S_IFDIR;
  	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
  			       mode, &fid, &status, &cb, &server);
  	if (ret < 0)
  		goto mkdir_error;
  
  	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
  	if (IS_ERR(inode)) {
  		/* ENOMEM at a really inconvenient time - just abandon the new
  		 * directory on the server */
  		ret = PTR_ERR(inode);
  		goto iget_error;
  	}
  
  	/* apply the status report we've got for the new vnode */
  	vnode = AFS_FS_I(inode);
  	spin_lock(&vnode->lock);
  	vnode->update_cnt++;
  	spin_unlock(&vnode->lock);
  	afs_vnode_finalise_status_update(vnode, server);
  	afs_put_server(server);
  
  	d_instantiate(dentry, inode);
  	if (d_unhashed(dentry)) {
  		_debug("not hashed");
  		d_rehash(dentry);
  	}
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  iget_error:
  	afs_put_server(server);
  mkdir_error:
  	key_put(key);
  error:
  	d_drop(dentry);
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * remove a directory from an AFS filesystem
   */
  static int afs_rmdir(struct inode *dir, struct dentry *dentry)
  {
  	struct afs_vnode *dvnode, *vnode;
  	struct key *key;
  	int ret;
  
  	dvnode = AFS_FS_I(dir);
  
  	_enter("{%x:%u},{%s}",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, true);
  	if (ret < 0)
  		goto rmdir_error;
  
  	if (dentry->d_inode) {
  		vnode = AFS_FS_I(dentry->d_inode);
  		clear_nlink(&vnode->vfs_inode);
  		set_bit(AFS_VNODE_DELETED, &vnode->flags);
  		afs_discard_callback_on_delete(vnode);
  	}
  
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  rmdir_error:
  	key_put(key);
  error:
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * remove a file from an AFS filesystem
   */
  static int afs_unlink(struct inode *dir, struct dentry *dentry)
  {
  	struct afs_vnode *dvnode, *vnode;
  	struct key *key;
  	int ret;
  
  	dvnode = AFS_FS_I(dir);
  
  	_enter("{%x:%u},{%s}",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);
  
  	ret = -ENAMETOOLONG;
  	if (dentry->d_name.len >= AFSNAMEMAX)
  		goto error;
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	if (dentry->d_inode) {
  		vnode = AFS_FS_I(dentry->d_inode);
  
  		/* make sure we have a callback promise on the victim */
  		ret = afs_validate(vnode, key);
  		if (ret < 0)
  			goto error;
  	}
  
  	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, false);
  	if (ret < 0)
  		goto remove_error;
  
  	if (dentry->d_inode) {
  		/* if the file wasn't deleted due to excess hard links, the
  		 * fileserver will break the callback promise on the file - if
  		 * it had one - before it returns to us, and if it was deleted,
  		 * it won't
  		 *
  		 * however, if we didn't have a callback promise outstanding,
  		 * or it was outstanding on a different server, then it won't
  		 * break it either...
  		 */
  		vnode = AFS_FS_I(dentry->d_inode);
  		if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
  			_debug("AFS_VNODE_DELETED");
  		if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
  			_debug("AFS_VNODE_CB_BROKEN");
  		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
  		ret = afs_validate(vnode, key);
  		_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
  	}
  
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  remove_error:
  	key_put(key);
  error:
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * create a regular file on an AFS filesystem
   */
  static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  		      bool excl)
  {
  	struct afs_file_status status;
  	struct afs_callback cb;
  	struct afs_server *server;
  	struct afs_vnode *dvnode, *vnode;
  	struct afs_fid fid;
  	struct inode *inode;
  	struct key *key;
  	int ret;
  
  	dvnode = AFS_FS_I(dir);
  
  	_enter("{%x:%u},{%s},%ho,",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	mode |= S_IFREG;
  	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
  			       mode, &fid, &status, &cb, &server);
  	if (ret < 0)
  		goto create_error;
  
  	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
  	if (IS_ERR(inode)) {
  		/* ENOMEM at a really inconvenient time - just abandon the new
  		 * directory on the server */
  		ret = PTR_ERR(inode);
  		goto iget_error;
  	}
  
  	/* apply the status report we've got for the new vnode */
  	vnode = AFS_FS_I(inode);
  	spin_lock(&vnode->lock);
  	vnode->update_cnt++;
  	spin_unlock(&vnode->lock);
  	afs_vnode_finalise_status_update(vnode, server);
  	afs_put_server(server);
  
  	d_instantiate(dentry, inode);
  	if (d_unhashed(dentry)) {
  		_debug("not hashed");
  		d_rehash(dentry);
  	}
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  iget_error:
  	afs_put_server(server);
  create_error:
  	key_put(key);
  error:
  	d_drop(dentry);
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * create a hard link between files in an AFS filesystem
   */
  static int afs_link(struct dentry *from, struct inode *dir,
  		    struct dentry *dentry)
  {
  	struct afs_vnode *dvnode, *vnode;
  	struct key *key;
  	int ret;
  
  	vnode = AFS_FS_I(from->d_inode);
  	dvnode = AFS_FS_I(dir);
  
  	_enter("{%x:%u},{%x:%u},{%s}",
  	       vnode->fid.vid, vnode->fid.vnode,
  	       dvnode->fid.vid, dvnode->fid.vnode,
  	       dentry->d_name.name);
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	ret = afs_vnode_link(dvnode, vnode, key, dentry->d_name.name);
  	if (ret < 0)
  		goto link_error;
  
  	ihold(&vnode->vfs_inode);
  	d_instantiate(dentry, &vnode->vfs_inode);
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  link_error:
  	key_put(key);
  error:
  	d_drop(dentry);
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * create a symlink in an AFS filesystem
   */
  static int afs_symlink(struct inode *dir, struct dentry *dentry,
  		       const char *content)
  {
  	struct afs_file_status status;
  	struct afs_server *server;
  	struct afs_vnode *dvnode, *vnode;
  	struct afs_fid fid;
  	struct inode *inode;
  	struct key *key;
  	int ret;
  
  	dvnode = AFS_FS_I(dir);
  
  	_enter("{%x:%u},{%s},%s",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name,
  	       content);
  
  	ret = -EINVAL;
  	if (strlen(content) >= AFSPATHMAX)
  		goto error;
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	ret = afs_vnode_symlink(dvnode, key, dentry->d_name.name, content,
  				&fid, &status, &server);
  	if (ret < 0)
  		goto create_error;
  
  	inode = afs_iget(dir->i_sb, key, &fid, &status, NULL);
  	if (IS_ERR(inode)) {
  		/* ENOMEM at a really inconvenient time - just abandon the new
  		 * directory on the server */
  		ret = PTR_ERR(inode);
  		goto iget_error;
  	}
  
  	/* apply the status report we've got for the new vnode */
  	vnode = AFS_FS_I(inode);
  	spin_lock(&vnode->lock);
  	vnode->update_cnt++;
  	spin_unlock(&vnode->lock);
  	afs_vnode_finalise_status_update(vnode, server);
  	afs_put_server(server);
  
  	d_instantiate(dentry, inode);
  	if (d_unhashed(dentry)) {
  		_debug("not hashed");
  		d_rehash(dentry);
  	}
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  iget_error:
  	afs_put_server(server);
  create_error:
  	key_put(key);
  error:
  	d_drop(dentry);
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * rename a file in an AFS filesystem and/or move it between directories
   */
  static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
  		      struct inode *new_dir, struct dentry *new_dentry)
  {
  	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
  	struct key *key;
  	int ret;
  
  	vnode = AFS_FS_I(old_dentry->d_inode);
  	orig_dvnode = AFS_FS_I(old_dir);
  	new_dvnode = AFS_FS_I(new_dir);
  
  	_enter("{%x:%u},{%x:%u},{%x:%u},{%s}",
  	       orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
  	       vnode->fid.vid, vnode->fid.vnode,
  	       new_dvnode->fid.vid, new_dvnode->fid.vnode,
  	       new_dentry->d_name.name);
  
  	key = afs_request_key(orig_dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	ret = afs_vnode_rename(orig_dvnode, new_dvnode, key,
  			       old_dentry->d_name.name,
  			       new_dentry->d_name.name);
  	if (ret < 0)
  		goto rename_error;
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  rename_error:
  	key_put(key);
  error:
  	d_drop(new_dentry);
  	_leave(" = %d", ret);
  	return ret;
  }