// SPDX-License-Identifier: GPL-2.0-or-later

  /* dir.c: AFS filesystem directory handling
   *

   * Copyright (C) 2002, 2018 Red Hat, Inc. All Rights Reserved.

   * Written by David Howells (dhowells@redhat.com)

   */
  
  #include <linux/kernel.h>

  #include <linux/fs.h>

  #include <linux/namei.h>

  #include <linux/pagemap.h>

  #include <linux/swap.h>

  #include <linux/ctype.h>

  #include <linux/sched.h>

  #include <linux/task_io_accounting_ops.h>

  #include "internal.h"

  #include "afs_fs.h"

  #include "xdr_fs.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_iput(struct dentry *dentry, struct inode *inode);

  static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, int nlen,

  				  loff_t fpos, u64 ino, unsigned dtype);

  static int afs_lookup_filldir(struct dir_context *ctx, 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,
  		      unsigned int flags);

  static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags);
  static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
  				   unsigned int length);
  
  static int afs_dir_set_page_dirty(struct page *page)
  {
  	BUG(); /* This should never happen. */
  }

  const struct file_operations afs_dir_file_operations = {

  	.open		= afs_dir_open,

  	.release	= afs_release,

  	.iterate_shared	= 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,

  	.listxattr	= afs_listxattr,

  };

  const struct address_space_operations afs_dir_aops = {
  	.set_page_dirty	= afs_dir_set_page_dirty,
  	.releasepage	= afs_dir_releasepage,
  	.invalidatepage	= afs_dir_invalidatepage,
  };

  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,

  	.d_iput		= afs_d_iput,

  };

  struct afs_lookup_one_cookie {
  	struct dir_context	ctx;
  	struct qstr		name;
  	bool			found;
  	struct afs_fid		fid;
  };

  struct afs_lookup_cookie {

  	struct dir_context	ctx;
  	struct qstr		name;
  	bool			found;
  	bool			one_only;
  	unsigned short		nr_fids;

  	struct afs_fid		fids[50];

  };

  /*
   * check that a directory page is valid
   */

  static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
  			       loff_t i_size)

  {

  	struct afs_xdr_dir_page *dbuf;

  	loff_t latter, off;

  	int tmp, qty;

  	/* Determine how many magic numbers there should be in this page, but
  	 * we must take care because the directory may change size under us.
  	 */
  	off = page_offset(page);

  	if (i_size <= off)
  		goto checked;
  
  	latter = i_size - off;

  	if (latter >= PAGE_SIZE)
  		qty = PAGE_SIZE;
  	else
  		qty = latter;

  	qty /= sizeof(union afs_xdr_dir_block);

  
  	/* check them */

  	dbuf = kmap(page);

  	for (tmp = 0; tmp < qty; tmp++) {

  		if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {

  			printk("kAFS: %s(%lx): bad magic %d/%d is %04hx
  ",

  			       __func__, dvnode->vfs_inode.i_ino, tmp, qty,

  			       ntohs(dbuf->blocks[tmp].hdr.magic));

  			trace_afs_dir_check_failed(dvnode, off, i_size);

  			kunmap(page);

  			trace_afs_file_error(dvnode, -EIO, afs_file_error_dir_bad_magic);

  			goto error;
  		}

  
  		/* Make sure each block is NUL terminated so we can reasonably
  		 * use string functions on it.  The filenames in the page
  		 * *should* be NUL-terminated anyway.
  		 */
  		((u8 *)&dbuf->blocks[tmp])[AFS_DIR_BLOCK_SIZE - 1] = 0;

  	}

  	kunmap(page);

  checked:

  	afs_stat_v(dvnode, n_read_dir);

  	return true;

  error:

  	return false;

  }

  /*

   * Check the contents of a directory that we've just read.
   */
  static bool afs_dir_check_pages(struct afs_vnode *dvnode, struct afs_read *req)
  {
  	struct afs_xdr_dir_page *dbuf;
  	unsigned int i, j, qty = PAGE_SIZE / sizeof(union afs_xdr_dir_block);
  
  	for (i = 0; i < req->nr_pages; i++)
  		if (!afs_dir_check_page(dvnode, req->pages[i], req->actual_len))
  			goto bad;
  	return true;
  
  bad:
  	pr_warn("DIR %llx:%llx f=%llx l=%llx al=%llx r=%llx
  ",
  		dvnode->fid.vid, dvnode->fid.vnode,
  		req->file_size, req->len, req->actual_len, req->remain);
  	pr_warn("DIR %llx %x %x %x
  ",
  		req->pos, req->index, req->nr_pages, req->offset);
  
  	for (i = 0; i < req->nr_pages; i++) {
  		dbuf = kmap(req->pages[i]);
  		for (j = 0; j < qty; j++) {
  			union afs_xdr_dir_block *block = &dbuf->blocks[j];
  
  			pr_warn("[%02x] %32phN
  ", i * qty + j, block);
  		}
  		kunmap(req->pages[i]);
  	}
  	return false;
  }
  
  /*

   * 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_xdr_dir_block) != 2048);
  	BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);

  	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))

  		return -ENOENT;

  	return afs_open(inode, file);

  }

  /*

   * Read the directory into the pagecache in one go, scrubbing the previous
   * contents.  The list of pages is returned, pinning them so that they don't
   * get reclaimed during the iteration.
   */
  static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)

  	__acquires(&dvnode->validate_lock)

  {
  	struct afs_read *req;
  	loff_t i_size;
  	int nr_pages, nr_inline, i, n;
  	int ret = -ENOMEM;
  
  retry:
  	i_size = i_size_read(&dvnode->vfs_inode);
  	if (i_size < 2048)

  		return ERR_PTR(afs_bad(dvnode, afs_file_error_dir_small));
  	if (i_size > 2048 * 1024) {
  		trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big);

  		return ERR_PTR(-EFBIG);

  	}

  
  	_enter("%llu", i_size);
  
  	/* Get a request record to hold the page list.  We want to hold it
  	 * inline if we can, but we don't want to make an order 1 allocation.
  	 */
  	nr_pages = (i_size + PAGE_SIZE - 1) / PAGE_SIZE;
  	nr_inline = nr_pages;
  	if (nr_inline > (PAGE_SIZE - sizeof(*req)) / sizeof(struct page *))
  		nr_inline = 0;

  	req = kzalloc(struct_size(req, array, nr_inline), GFP_KERNEL);

  	if (!req)
  		return ERR_PTR(-ENOMEM);
  
  	refcount_set(&req->usage, 1);
  	req->nr_pages = nr_pages;
  	req->actual_len = i_size; /* May change */
  	req->len = nr_pages * PAGE_SIZE; /* We can ask for more than there is */
  	req->data_version = dvnode->status.data_version; /* May change */
  	if (nr_inline > 0) {
  		req->pages = req->array;
  	} else {
  		req->pages = kcalloc(nr_pages, sizeof(struct page *),
  				     GFP_KERNEL);
  		if (!req->pages)
  			goto error;
  	}
  
  	/* Get a list of all the pages that hold or will hold the directory
  	 * content.  We need to fill in any gaps that we might find where the
  	 * memory reclaimer has been at work.  If there are any gaps, we will
  	 * need to reread the entire directory contents.
  	 */
  	i = 0;
  	do {
  		n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
  					  req->nr_pages - i,
  					  req->pages + i);
  		_debug("find %u at %u/%u", n, i, req->nr_pages);
  		if (n == 0) {
  			gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;
  
  			if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
  				afs_stat_v(dvnode, n_inval);
  
  			ret = -ENOMEM;
  			req->pages[i] = __page_cache_alloc(gfp);
  			if (!req->pages[i])
  				goto error;
  			ret = add_to_page_cache_lru(req->pages[i],
  						    dvnode->vfs_inode.i_mapping,
  						    i, gfp);
  			if (ret < 0)
  				goto error;

  			attach_page_private(req->pages[i], (void *)1);

  			unlock_page(req->pages[i]);
  			i++;
  		} else {
  			i += n;
  		}
  	} while (i < req->nr_pages);
  
  	/* If we're going to reload, we need to lock all the pages to prevent
  	 * races.
  	 */

  	ret = -ERESTARTSYS;
  	if (down_read_killable(&dvnode->validate_lock) < 0)
  		goto error;

  	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
  		goto success;

  	up_read(&dvnode->validate_lock);
  	if (down_write_killable(&dvnode->validate_lock) < 0)
  		goto error;
  
  	if (!test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {

  		trace_afs_reload_dir(dvnode);

  		ret = afs_fetch_data(dvnode, key, req);
  		if (ret < 0)

  			goto error_unlock;

  
  		task_io_account_read(PAGE_SIZE * req->nr_pages);
  
  		if (req->len < req->file_size)
  			goto content_has_grown;
  
  		/* Validate the data we just read. */
  		ret = -EIO;

  		if (!afs_dir_check_pages(dvnode, req))
  			goto error_unlock;

  
  		// TODO: Trim excess pages
  
  		set_bit(AFS_VNODE_DIR_VALID, &dvnode->flags);
  	}

  	downgrade_write(&dvnode->validate_lock);

  success:

  	return req;

  error_unlock:

  	up_write(&dvnode->validate_lock);

  error:
  	afs_put_read(req);
  	_leave(" = %d", ret);
  	return ERR_PTR(ret);
  
  content_has_grown:

  	up_write(&dvnode->validate_lock);

  	afs_put_read(req);
  	goto retry;
  }
  
  /*

   * deal with one block in an AFS directory
   */

  static int afs_dir_iterate_block(struct afs_vnode *dvnode,
  				 struct dir_context *ctx,

  				 union afs_xdr_dir_block *block,

  				 unsigned blkoff)

  {

  	union afs_xdr_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_xdr_dirent);

  
  	/* walk through the block, an entry at a time */

  	for (offset = (blkoff == 0 ? AFS_DIR_RESV_BLOCKS0 : AFS_DIR_RESV_BLOCKS);
  	     offset < AFS_DIR_SLOTS_PER_BLOCK;

  	     offset = next
  	     ) {
  		next = offset + 1;
  
  		/* skip entries marked unused in the bitmap */

  		if (!(block->hdr.bitmap[offset / 8] &

  		      (1 << (offset % 8)))) {

  			_debug("ENT[%zu.%u]: unused",

  			       blkoff / sizeof(union afs_xdr_dir_block), offset);

  			if (offset >= curr)

  				ctx->pos = blkoff +

  					next * sizeof(union afs_xdr_dirent);

  			continue;
  		}
  
  		/* got a valid entry */
  		dire = &block->dirents[offset];
  		nlen = strnlen(dire->u.name,
  			       sizeof(*block) -

  			       offset * sizeof(union afs_xdr_dirent));

  		_debug("ENT[%zu.%u]: %s %zu \"%s\"",

  		       blkoff / sizeof(union afs_xdr_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_xdr_dirent)) {

  			if (next >= AFS_DIR_SLOTS_PER_BLOCK) {

  				_debug("ENT[%zu.%u]:"

  				       " %u travelled beyond end dir block"

  				       " (len %u/%zu)",

  				       blkoff / sizeof(union afs_xdr_dir_block),

  				       offset, next, tmp, nlen);

  				return afs_bad(dvnode, afs_file_error_dir_over_end);

  			}

  			if (!(block->hdr.bitmap[next / 8] &

  			      (1 << (next % 8)))) {

  				_debug("ENT[%zu.%u]:"
  				       " %u unmarked extension (len %u/%zu)",

  				       blkoff / sizeof(union afs_xdr_dir_block),

  				       offset, next, tmp, nlen);

  				return afs_bad(dvnode, afs_file_error_dir_unmarked_ext);

  			}

  			_debug("ENT[%zu.%u]: ext %u/%zu",

  			       blkoff / sizeof(union afs_xdr_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 ||
  			       ctx->actor == afs_lookup_one_filldir)?

  			      ntohl(dire->u.unique) : DT_UNKNOWN)) {

  			_leave(" = 0 [full]");
  			return 0;
  		}

  		ctx->pos = blkoff + next * sizeof(union afs_xdr_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, afs_dataversion_t *_dir_version)

  {

  	struct afs_vnode *dvnode = AFS_FS_I(dir);

  	struct afs_xdr_dir_page *dbuf;
  	union afs_xdr_dir_block *dblock;

  	struct afs_read *req;

  	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;
  	}

  	req = afs_read_dir(dvnode, key);
  	if (IS_ERR(req))
  		return PTR_ERR(req);

  	*_dir_version = req->data_version;

  	/* round the file position up to the next entry boundary */

  	ctx->pos += sizeof(union afs_xdr_dirent) - 1;
  	ctx->pos &= ~(sizeof(union afs_xdr_dirent) - 1);

  
  	/* walk through the blocks in sequence */
  	ret = 0;

  	while (ctx->pos < req->actual_len) {

  		blkoff = ctx->pos & ~(sizeof(union afs_xdr_dir_block) - 1);

  		/* Fetch the appropriate page from the directory and re-add it
  		 * to the LRU.
  		 */
  		page = req->pages[blkoff / PAGE_SIZE];
  		if (!page) {

  			ret = afs_bad(dvnode, afs_file_error_dir_missing_page);

  			break;
  		}

  		mark_page_accessed(page);

  
  		limit = blkoff & ~(PAGE_SIZE - 1);

  		dbuf = kmap(page);

  
  		/* deal with the individual blocks stashed on this page */
  		do {
  			dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /

  					       sizeof(union afs_xdr_dir_block)];

  			ret = afs_dir_iterate_block(dvnode, ctx, dblock, blkoff);

  			if (ret != 1) {

  				kunmap(page);

  				goto out;
  			}

  			blkoff += sizeof(union afs_xdr_dir_block);

  		} while (ctx->pos < dir->i_size && blkoff < limit);

  		kunmap(page);

  		ret = 0;
  	}

  out:

  	up_read(&dvnode->validate_lock);

  	afs_put_read(req);

  	_leave(" = %d", ret);
  	return ret;

  }

  /*
   * read an AFS directory
   */

  static int afs_readdir(struct file *file, struct dir_context *ctx)

  {

  	afs_dataversion_t dir_version;
  
  	return afs_dir_iterate(file_inode(file), ctx, afs_file_key(file),
  			       &dir_version);

  }

  /*

   * Search the directory for a single name

   * - if afs_dir_iterate_block() spots this function, it'll pass the FID
   *   uniquifier through dtype
   */

  static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name,
  				  int nlen, loff_t fpos, u64 ino, unsigned dtype)

  {

  	struct afs_lookup_one_cookie *cookie =
  		container_of(ctx, struct afs_lookup_one_cookie, ctx);

  	_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_xdr_dir_block) != 2048);
  	BUILD_BUG_ON(sizeof(union afs_xdr_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 of a single name in a directory

   * - just returns the FID the dentry name maps to if found

   */

  static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry,

  			     struct afs_fid *fid, struct key *key,
  			     afs_dataversion_t *_dir_version)

  {

  	struct afs_super_info *as = dir->i_sb->s_fs_info;

  	struct afs_lookup_one_cookie cookie = {
  		.ctx.actor = afs_lookup_one_filldir,

  		.name = dentry->d_name,
  		.fid.vid = as->volume->vid
  	};

  	int ret;

  	_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);

  	/* search the directory */

  	ret = afs_dir_iterate(dir, &cookie.ctx, key, _dir_version);

  	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=%llu u=%u }", fid->vnode, fid->unique);

  	return 0;
  }
  
  /*

   * 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(struct dir_context *ctx, const char *name,
  			      int nlen, loff_t fpos, u64 ino, unsigned dtype)
  {
  	struct afs_lookup_cookie *cookie =
  		container_of(ctx, struct afs_lookup_cookie, ctx);
  	int ret;
  
  	_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_xdr_dir_block) != 2048);
  	BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);

  
  	if (cookie->found) {
  		if (cookie->nr_fids < 50) {
  			cookie->fids[cookie->nr_fids].vnode	= ino;
  			cookie->fids[cookie->nr_fids].unique	= dtype;
  			cookie->nr_fids++;
  		}
  	} else if (cookie->name.len == nlen &&
  		   memcmp(cookie->name.name, name, nlen) == 0) {

  		cookie->fids[1].vnode	= ino;
  		cookie->fids[1].unique	= dtype;

  		cookie->found = 1;
  		if (cookie->one_only)
  			return -1;
  	}
  
  	ret = cookie->nr_fids >= 50 ? -1 : 0;
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*

   * Deal with the result of a successful lookup operation.  Turn all the files
   * into inodes and save the first one - which is the one we actually want.
   */
  static void afs_do_lookup_success(struct afs_operation *op)
  {
  	struct afs_vnode_param *vp;
  	struct afs_vnode *vnode;
  	struct inode *inode;
  	u32 abort_code;
  	int i;
  
  	_enter("");
  
  	for (i = 0; i < op->nr_files; i++) {
  		switch (i) {
  		case 0:
  			vp = &op->file[0];
  			abort_code = vp->scb.status.abort_code;
  			if (abort_code != 0) {

  				op->ac.abort_code = abort_code;

  				op->error = afs_abort_to_error(abort_code);
  			}
  			break;
  
  		case 1:
  			vp = &op->file[1];
  			break;
  
  		default:
  			vp = &op->more_files[i - 2];
  			break;
  		}
  
  		if (!vp->scb.have_status && !vp->scb.have_error)
  			continue;
  
  		_debug("do [%u]", i);
  		if (vp->vnode) {
  			if (!test_bit(AFS_VNODE_UNSET, &vp->vnode->flags))
  				afs_vnode_commit_status(op, vp);
  		} else if (vp->scb.status.abort_code == 0) {
  			inode = afs_iget(op, vp);
  			if (!IS_ERR(inode)) {
  				vnode = AFS_FS_I(inode);
  				afs_cache_permit(vnode, op->key,
  						 0 /* Assume vnode->cb_break is 0 */ +
  						 op->cb_v_break,
  						 &vp->scb);
  				vp->vnode = vnode;
  				vp->put_vnode = true;
  			}
  		} else {
  			_debug("- abort %d %llx:%llx.%x",
  			       vp->scb.status.abort_code,
  			       vp->fid.vid, vp->fid.vnode, vp->fid.unique);
  		}
  	}
  
  	_leave("");
  }
  
  static const struct afs_operation_ops afs_inline_bulk_status_operation = {
  	.issue_afs_rpc	= afs_fs_inline_bulk_status,
  	.issue_yfs_rpc	= yfs_fs_inline_bulk_status,
  	.success	= afs_do_lookup_success,
  };

  static const struct afs_operation_ops afs_lookup_fetch_status_operation = {

  	.issue_afs_rpc	= afs_fs_fetch_status,
  	.issue_yfs_rpc	= yfs_fs_fetch_status,
  	.success	= afs_do_lookup_success,

  	.aborted	= afs_check_for_remote_deletion,

  };
  
  /*

   * See if we know that the server we expect to use doesn't support
   * FS.InlineBulkStatus.
   */
  static bool afs_server_supports_ibulk(struct afs_vnode *dvnode)
  {
  	struct afs_server_list *slist;
  	struct afs_volume *volume = dvnode->volume;
  	struct afs_server *server;
  	bool ret = true;
  	int i;
  
  	if (!test_bit(AFS_VOLUME_MAYBE_NO_IBULK, &volume->flags))
  		return true;
  
  	rcu_read_lock();
  	slist = rcu_dereference(volume->servers);
  
  	for (i = 0; i < slist->nr_servers; i++) {
  		server = slist->servers[i].server;
  		if (server == dvnode->cb_server) {
  			if (test_bit(AFS_SERVER_FL_NO_IBULK, &server->flags))
  				ret = false;
  			break;
  		}
  	}
  
  	rcu_read_unlock();
  	return ret;
  }
  
  /*

   * Do a lookup in a directory.  We make use of bulk lookup to query a slew of
   * files in one go and create inodes for them.  The inode of the file we were
   * asked for is returned.
   */
  static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
  				   struct key *key)
  {
  	struct afs_lookup_cookie *cookie;

  	struct afs_vnode_param *vp;
  	struct afs_operation *op;

  	struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode;
  	struct inode *inode = NULL, *ti;

  	afs_dataversion_t data_version = READ_ONCE(dvnode->status.data_version);

  	long ret;
  	int i;

  
  	_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
  
  	cookie = kzalloc(sizeof(struct afs_lookup_cookie), GFP_KERNEL);
  	if (!cookie)
  		return ERR_PTR(-ENOMEM);

  	for (i = 0; i < ARRAY_SIZE(cookie->fids); i++)
  		cookie->fids[i].vid = dvnode->fid.vid;

  	cookie->ctx.actor = afs_lookup_filldir;
  	cookie->name = dentry->d_name;

  	cookie->nr_fids = 2; /* slot 0 is saved for the fid we actually want
  			      * and slot 1 for the directory */

  	if (!afs_server_supports_ibulk(dvnode))
  		cookie->one_only = true;

  	/* search the directory */

  	ret = afs_dir_iterate(dir, &cookie->ctx, key, &data_version);

  	if (ret < 0)

  		goto out;

  	dentry->d_fsdata = (void *)(unsigned long)data_version;

  	ret = -ENOENT;

  	if (!cookie->found)
  		goto out;
  
  	/* Check to see if we already have an inode for the primary fid. */

  	inode = ilookup5(dir->i_sb, cookie->fids[1].vnode,
  			 afs_ilookup5_test_by_fid, &cookie->fids[1]);

  	if (inode)

  		goto out; /* We do */

  	/* Okay, we didn't find it.  We need to query the server - and whilst
  	 * we're doing that, we're going to attempt to look up a bunch of other
  	 * vnodes also.
  	 */
  	op = afs_alloc_operation(NULL, dvnode->volume);
  	if (IS_ERR(op)) {
  		ret = PTR_ERR(op);

  		goto out;

  	}

  	afs_op_set_vnode(op, 0, dvnode);
  	afs_op_set_fid(op, 1, &cookie->fids[1]);

  	op->nr_files = cookie->nr_fids;
  	_debug("nr_files %u", op->nr_files);

  	/* Need space for examining all the selected files */
  	op->error = -ENOMEM;
  	if (op->nr_files > 2) {
  		op->more_files = kvcalloc(op->nr_files - 2,
  					  sizeof(struct afs_vnode_param),
  					  GFP_KERNEL);
  		if (!op->more_files)
  			goto out_op;
  
  		for (i = 2; i < op->nr_files; i++) {
  			vp = &op->more_files[i - 2];
  			vp->fid = cookie->fids[i];
  
  			/* Find any inodes that already exist and get their
  			 * callback counters.
  			 */
  			ti = ilookup5_nowait(dir->i_sb, vp->fid.vnode,
  					     afs_ilookup5_test_by_fid, &vp->fid);
  			if (!IS_ERR_OR_NULL(ti)) {
  				vnode = AFS_FS_I(ti);
  				vp->dv_before = vnode->status.data_version;
  				vp->cb_break_before = afs_calc_vnode_cb_break(vnode);
  				vp->vnode = vnode;
  				vp->put_vnode = true;

  				vp->speculative = true; /* vnode not locked */

  			}

  		}
  	}

  	/* Try FS.InlineBulkStatus first.  Abort codes for the individual
  	 * lookups contained therein are stored in the reply without aborting
  	 * the whole operation.
  	 */

  	op->error = -ENOTSUPP;
  	if (!cookie->one_only) {
  		op->ops = &afs_inline_bulk_status_operation;
  		afs_begin_vnode_operation(op);
  		afs_wait_for_operation(op);

  	}

  	if (op->error == -ENOTSUPP) {
  		/* We could try FS.BulkStatus next, but this aborts the entire
  		 * op if any of the lookups fails - so, for the moment, revert
  		 * to FS.FetchStatus for op->file[1].
  		 */
  		op->fetch_status.which = 1;

  		op->ops = &afs_lookup_fetch_status_operation;

  		afs_begin_vnode_operation(op);
  		afs_wait_for_operation(op);

  	}

  	inode = ERR_PTR(op->error);

  out_op:
  	if (op->error == 0) {
  		inode = &op->file[1].vnode->vfs_inode;
  		op->file[1].vnode = NULL;

  	}

  	if (op->file[0].scb.have_status)
  		dentry->d_fsdata = (void *)(unsigned long)op->file[0].scb.status.data_version;
  	else
  		dentry->d_fsdata = (void *)(unsigned long)op->file[0].dv_before;
  	ret = afs_put_operation(op);

  out:
  	kfree(cookie);

  	_leave("");
  	return inode ?: ERR_PTR(ret);

  }
  
  /*

   * Look up an entry in a directory with @sys substitution.
   */
  static struct dentry *afs_lookup_atsys(struct inode *dir, struct dentry *dentry,
  				       struct key *key)
  {
  	struct afs_sysnames *subs;
  	struct afs_net *net = afs_i2net(dir);
  	struct dentry *ret;
  	char *buf, *p, *name;
  	int len, i;
  
  	_enter("");
  
  	ret = ERR_PTR(-ENOMEM);
  	p = buf = kmalloc(AFSNAMEMAX, GFP_KERNEL);
  	if (!buf)
  		goto out_p;
  	if (dentry->d_name.len > 4) {
  		memcpy(p, dentry->d_name.name, dentry->d_name.len - 4);
  		p += dentry->d_name.len - 4;
  	}
  
  	/* There is an ordered list of substitutes that we have to try. */
  	read_lock(&net->sysnames_lock);
  	subs = net->sysnames;
  	refcount_inc(&subs->usage);
  	read_unlock(&net->sysnames_lock);
  
  	for (i = 0; i < subs->nr; i++) {
  		name = subs->subs[i];
  		len = dentry->d_name.len - 4 + strlen(name);
  		if (len >= AFSNAMEMAX) {
  			ret = ERR_PTR(-ENAMETOOLONG);
  			goto out_s;
  		}
  
  		strcpy(p, name);
  		ret = lookup_one_len(buf, dentry->d_parent, len);
  		if (IS_ERR(ret) || d_is_positive(ret))
  			goto out_s;
  		dput(ret);
  	}
  
  	/* We don't want to d_add() the @sys dentry here as we don't want to
  	 * the cached dentry to hide changes to the sysnames list.
  	 */
  	ret = NULL;
  out_s:
  	afs_put_sysnames(subs);
  	kfree(buf);
  out_p:
  	key_put(key);
  	return 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 *dvnode = AFS_FS_I(dir);

  	struct afs_fid fid = {};

  	struct inode *inode;

  	struct dentry *d;

  	struct key *key;

  	int ret;

  	_enter("{%llx:%llu},%p{%pd},",

  	       dvnode->fid.vid, dvnode->fid.vnode, dentry, dentry);

  	ASSERTCMP(d_inode(dentry), ==, NULL);

  	if (dentry->d_name.len >= AFSNAMEMAX) {

  		_leave(" = -ENAMETOOLONG");
  		return ERR_PTR(-ENAMETOOLONG);
  	}

  	if (test_bit(AFS_VNODE_DELETED, &dvnode->flags)) {

  		_leave(" = -ESTALE");
  		return ERR_PTR(-ESTALE);
  	}

  	key = afs_request_key(dvnode->volume->cell);

  	if (IS_ERR(key)) {
  		_leave(" = %ld [key]", PTR_ERR(key));

  		return ERR_CAST(key);

  	}

  	ret = afs_validate(dvnode, key);

  	if (ret < 0) {
  		key_put(key);
  		_leave(" = %d [val]", ret);
  		return ERR_PTR(ret);
  	}

  	if (dentry->d_name.len >= 4 &&
  	    dentry->d_name.name[dentry->d_name.len - 4] == '@' &&
  	    dentry->d_name.name[dentry->d_name.len - 3] == 's' &&
  	    dentry->d_name.name[dentry->d_name.len - 2] == 'y' &&
  	    dentry->d_name.name[dentry->d_name.len - 1] == 's')
  		return afs_lookup_atsys(dir, dentry, key);

  	afs_stat_v(dvnode, n_lookup);

  	inode = afs_do_lookup(dir, dentry, key);

  	key_put(key);

  	if (inode == ERR_PTR(-ENOENT))

  		inode = afs_try_auto_mntpt(dentry, dir);

  
  	if (!IS_ERR_OR_NULL(inode))
  		fid = AFS_FS_I(inode)->fid;

  	_debug("splice %p", dentry->d_inode);

  	d = d_splice_alias(inode, dentry);

  	if (!IS_ERR_OR_NULL(d)) {

  		d->d_fsdata = dentry->d_fsdata;

  		trace_afs_lookup(dvnode, &d->d_name, &fid);

  	} else {

  		trace_afs_lookup(dvnode, &dentry->d_name, &fid);

  	}

  	_leave("");

  	return d;

  }

  /*

   * Check the validity of a dentry under RCU conditions.
   */
  static int afs_d_revalidate_rcu(struct dentry *dentry)
  {
  	struct afs_vnode *dvnode, *vnode;
  	struct dentry *parent;
  	struct inode *dir, *inode;
  	long dir_version, de_version;
  
  	_enter("%p", dentry);
  
  	/* Check the parent directory is still valid first. */
  	parent = READ_ONCE(dentry->d_parent);
  	dir = d_inode_rcu(parent);
  	if (!dir)
  		return -ECHILD;
  	dvnode = AFS_FS_I(dir);
  	if (test_bit(AFS_VNODE_DELETED, &dvnode->flags))
  		return -ECHILD;
  
  	if (!afs_check_validity(dvnode))
  		return -ECHILD;
  
  	/* We only need to invalidate a dentry if the server's copy changed
  	 * behind our back.  If we made the change, it's no problem.  Note that
  	 * on a 32-bit system, we only have 32 bits in the dentry to store the
  	 * version.
  	 */
  	dir_version = (long)READ_ONCE(dvnode->status.data_version);
  	de_version = (long)READ_ONCE(dentry->d_fsdata);
  	if (de_version != dir_version) {
  		dir_version = (long)READ_ONCE(dvnode->invalid_before);
  		if (de_version - dir_version < 0)
  			return -ECHILD;
  	}
  
  	/* Check to see if the vnode referred to by the dentry still
  	 * has a callback.
  	 */
  	if (d_really_is_positive(dentry)) {
  		inode = d_inode_rcu(dentry);
  		if (inode) {
  			vnode = AFS_FS_I(inode);
  			if (!afs_check_validity(vnode))
  				return -ECHILD;
  		}
  	}
  
  	return 1; /* Still valid */
  }
  
  /*

   * 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 fid;

  	struct dentry *parent;

  	struct inode *inode;

  	struct key *key;

  	afs_dataversion_t dir_version, invalid_before;

  	long de_version;

  	int ret;

  	if (flags & LOOKUP_RCU)

  		return afs_d_revalidate_rcu(dentry);

  	if (d_really_is_positive(dentry)) {
  		vnode = AFS_FS_I(d_inode(dentry));

  		_enter("{v={%llx:%llu} n=%pd fl=%lx},",

  		       vnode->fid.vid, vnode->fid.vnode, dentry,

  		       vnode->flags);

  	} else {

  		_enter("{neg n=%pd}", dentry);

  	}

  	key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);

  	if (IS_ERR(key))
  		key = NULL;

  	if (d_really_is_positive(dentry)) {
  		inode = d_inode(dentry);
  		if (inode) {
  			vnode = AFS_FS_I(inode);
  			afs_validate(vnode, key);
  			if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
  				goto out_bad;
  		}
  	}

  	/* lock down the parent dentry so we can peer at it */

  	parent = dget_parent(dentry);

  	dir = AFS_FS_I(d_inode(parent));

  	/* validate the parent directory */

  	afs_validate(dir, key);

  
  	if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {

  		_debug("%pd: parent dir deleted", dentry);

  		goto out_bad_parent;

  	}

  	/* We only need to invalidate a dentry if the server's copy changed
  	 * behind our back.  If we made the change, it's no problem.  Note that
  	 * on a 32-bit system, we only have 32 bits in the dentry to store the
  	 * version.
  	 */

  	dir_version = dir->status.data_version;

  	de_version = (long)dentry->d_fsdata;

  	if (de_version == (long)dir_version)

  		goto out_valid_noupdate;

  	invalid_before = dir->invalid_before;
  	if (de_version - (long)invalid_before >= 0)

  		goto out_valid;

  	_debug("dir modified");

  	afs_stat_v(dir, n_reval);

  
  	/* search the directory for this vnode */

  	ret = afs_do_lookup_one(&dir->vfs_inode, dentry, &fid, key, &dir_version);

  	switch (ret) {
  	case 0:
  		/* the filename maps to something */

  		if (d_really_is_negative(dentry))

  			goto out_bad_parent;
  		inode = d_inode(dentry);
  		if (is_bad_inode(inode)) {

  			printk("kAFS: afs_d_revalidate: %pd2 has bad inode
  ",
  			       dentry);

  			goto out_bad_parent;

  		}

  		vnode = AFS_FS_I(inode);

  		/* if the vnode ID has changed, then the dirent points to a
  		 * different file */

  		if (fid.vnode != vnode->fid.vnode) {

  			_debug("%pd: dirent changed [%llu != %llu]",

  			       dentry, 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("%pd: file deleted (uq %u -> %u I:%u)",
  			       dentry, fid.unique,

  			       vnode->fid.unique,

  			       vnode->vfs_inode.i_generation);
  			write_seqlock(&vnode->cb_lock);

  			set_bit(AFS_VNODE_DELETED, &vnode->flags);

  			write_sequnlock(&vnode->cb_lock);

  			goto not_found;

  		}

  		goto out_valid;

  	case -ENOENT:
  		/* the filename is unknown */

  		_debug("%pd: dirent not found", dentry);

  		if (d_really_is_positive(dentry))

  			goto not_found;
  		goto out_valid;

  	default:

  		_debug("failed to iterate dir %pd: %d",
  		       parent, ret);

  		goto out_bad_parent;

  	}

  out_valid:

  	dentry->d_fsdata = (void *)(unsigned long)dir_version;

  out_valid_noupdate:

  	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_parent:

  	_debug("dropping dentry %pd2", dentry);

  	dput(parent);

  out_bad:

  	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("%pd", dentry);

  
  	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
  		goto zap;

  	if (d_really_is_positive(dentry) &&
  	    (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(d_inode(dentry))->flags) ||
  	     test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(d_inode(dentry))->flags)))

  		goto zap;

  
  	_leave(" = 0 [keep]");
  	return 0;

  zap:

  	_leave(" = 1 [zap]");
  	return 1;

  }

  
  /*

   * Clean up sillyrename files on dentry removal.
   */
  static void afs_d_iput(struct dentry *dentry, struct inode *inode)
  {
  	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
  		afs_silly_iput(dentry, inode);
  	iput(inode);
  }
  
  /*

   * handle dentry release
   */

  void afs_d_release(struct dentry *dentry)

  {

  	_enter("%pd", dentry);

  }

  void afs_check_for_remote_deletion(struct afs_operation *op)
  {
  	struct afs_vnode *vnode = op->file[0].vnode;
  
  	switch (op->ac.abort_code) {
  	case VNOVNODE:
  		set_bit(AFS_VNODE_DELETED, &vnode->flags);
  		afs_break_callback(vnode, afs_cb_break_for_deleted);
  	}
  }

  /*

   * Create a new inode for create/mkdir/symlink
   */

  static void afs_vnode_new_inode(struct afs_operation *op)

  {

  	struct afs_vnode_param *vp = &op->file[1];

  	struct afs_vnode *vnode;

  	struct inode *inode;

  	_enter("");
  
  	ASSERTCMP(op->error, ==, 0);

  	inode = afs_iget(op, vp);

  	if (IS_ERR(inode)) {
  		/* ENOMEM or EINTR at a really inconvenient time - just abandon
  		 * the new directory on the server.
  		 */

  		op->error = PTR_ERR(inode);

  		return;
  	}

  	vnode = AFS_FS_I(inode);
  	set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);

  	if (!op->error)
  		afs_cache_permit(vnode, op->key, vnode->cb_break, &vp->scb);
  	d_instantiate(op->dentry, inode);

  }

  static void afs_create_success(struct afs_operation *op)

  {

  	_enter("op=%08x", op->debug_id);

  	op->ctime = op->file[0].scb.status.mtime_client;

  	afs_vnode_commit_status(op, &op->file[0]);
  	afs_update_dentry_version(op, &op->file[0], op->dentry);
  	afs_vnode_new_inode(op);

  }

  static void afs_create_edit_dir(struct afs_operation *op)

  {

  	struct afs_vnode_param *dvp = &op->file[0];
  	struct afs_vnode_param *vp = &op->file[1];
  	struct afs_vnode *dvnode = dvp->vnode;
  
  	_enter("op=%08x", op->debug_id);
  
  	down_write(&dvnode->validate_lock);
  	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  	    dvnode->status.data_version == dvp->dv_before + dvp->dv_delta)
  		afs_edit_dir_add(dvnode, &op->dentry->d_name, &vp->fid,
  				 op->create.reason);
  	up_write(&dvnode->validate_lock);

  }

  static void afs_create_put(struct afs_operation *op)
  {
  	_enter("op=%08x", op->debug_id);
  
  	if (op->error)
  		d_drop(op->dentry);
  }
  
  static const struct afs_operation_ops afs_mkdir_operation = {
  	.issue_afs_rpc	= afs_fs_make_dir,
  	.issue_yfs_rpc	= yfs_fs_make_dir,
  	.success	= afs_create_success,

  	.aborted	= afs_check_for_remote_deletion,

  	.edit_dir	= afs_create_edit_dir,
  	.put		= afs_create_put,
  };

  /*

   * create a directory on an AFS filesystem
   */

  static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)

  {

  	struct afs_operation *op;

  	struct afs_vnode *dvnode = AFS_FS_I(dir);

  	_enter("{%llx:%llu},{%pd},%ho",

  	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);

  	op = afs_alloc_operation(NULL, dvnode->volume);
  	if (IS_ERR(op)) {
  		d_drop(dentry);
  		return PTR_ERR(op);

  	}

  	afs_op_set_vnode(op, 0, dvnode);
  	op->file[0].dv_delta = 1;

  	op->file[0].update_ctime = true;

  	op->dentry	= dentry;
  	op->create.mode	= S_IFDIR | mode;
  	op->create.reason = afs_edit_dir_for_mkdir;
  	op->ops		= &afs_mkdir_operation;
  	return afs_do_sync_operation(op);

  }
  
  /*

   * Remove a subdir from a directory.
   */
  static void afs_dir_remove_subdir(struct dentry *dentry)
  {
  	if (d_really_is_positive(dentry)) {
  		struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
  
  		clear_nlink(&vnode->vfs_inode);
  		set_bit(AFS_VNODE_DELETED, &vnode->flags);
  		clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);

  		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);

  	}
  }

  static void afs_rmdir_success(struct afs_operation *op)
  {
  	_enter("op=%08x", op->debug_id);

  	op->ctime = op->file[0].scb.status.mtime_client;

  	afs_vnode_commit_status(op, &op->file[0]);
  	afs_update_dentry_version(op, &op->file[0], op->dentry);
  }
  
  static void afs_rmdir_edit_dir(struct afs_operation *op)
  {
  	struct afs_vnode_param *dvp = &op->file[0];
  	struct afs_vnode *dvnode = dvp->vnode;
  
  	_enter("op=%08x", op->debug_id);
  	afs_dir_remove_subdir(op->dentry);
  
  	down_write(&dvnode->validate_lock);
  	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  	    dvnode->status.data_version == dvp->dv_before + dvp->dv_delta)
  		afs_edit_dir_remove(dvnode, &op->dentry->d_name,
  				    afs_edit_dir_for_rmdir);
  	up_write(&dvnode->validate_lock);
  }
  
  static void afs_rmdir_put(struct afs_operation *op)
  {
  	_enter("op=%08x", op->debug_id);
  	if (op->file[1].vnode)
  		up_write(&op->file[1].vnode->rmdir_lock);
  }
  
  static const struct afs_operation_ops afs_rmdir_operation = {
  	.issue_afs_rpc	= afs_fs_remove_dir,
  	.issue_yfs_rpc	= yfs_fs_remove_dir,
  	.success	= afs_rmdir_success,

  	.aborted	= afs_check_for_remote_deletion,

  	.edit_dir	= afs_rmdir_edit_dir,
  	.put		= afs_rmdir_put,
  };

  /*

   * remove a directory from an AFS filesystem
   */
  static int afs_rmdir(struct inode *dir, struct dentry *dentry)
  {

  	struct afs_operation *op;

  	struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode = NULL;

  	int ret;

  	_enter("{%llx:%llu},{%pd}",

  	       dvnode->fid.vid, dvnode->fid.vnode, dentry);

  	op = afs_alloc_operation(NULL, dvnode->volume);
  	if (IS_ERR(op))
  		return PTR_ERR(op);

  	afs_op_set_vnode(op, 0, dvnode);
  	op->file[0].dv_delta = 1;

  	op->file[0].update_ctime = true;

  
  	op->dentry	= dentry;
  	op->ops		= &afs_rmdir_operation;

  	/* Try to make sure we have a callback promise on the victim. */
  	if (d_really_is_positive(dentry)) {
  		vnode = AFS_FS_I(d_inode(dentry));

  		ret = afs_validate(vnode, op->key);

  		if (ret < 0)

  			goto error;

  	}

  	if (vnode) {
  		ret = down_write_killable(&vnode->rmdir_lock);
  		if (ret < 0)

  			goto error;
  		op->file[1].vnode = vnode;

  	}

  	return afs_do_sync_operation(op);

  error:

  	return afs_put_operation(op);

  }
  
  /*

   * Remove a link to a file or symlink from a directory.
   *
   * If the file was not 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...
   */

  static void afs_dir_remove_link(struct afs_operation *op)

  {

  	struct afs_vnode *dvnode = op->file[0].vnode;
  	struct afs_vnode *vnode = op->file[1].vnode;
  	struct dentry *dentry = op->dentry;
  	int ret;

  	if (op->error != 0 ||
  	    (op->file[1].scb.have_status && op->file[1].scb.have_error))
  		return;
  	if (d_really_is_positive(dentry))
  		return;

  	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
  		/* Already done */
  	} else if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {
  		write_seqlock(&vnode->cb_lock);
  		drop_nlink(&vnode->vfs_inode);
  		if (vnode->vfs_inode.i_nlink == 0) {
  			set_bit(AFS_VNODE_DELETED, &vnode->flags);
  			__afs_break_callback(vnode, afs_cb_break_for_unlink);
  		}
  		write_sequnlock(&vnode->cb_lock);
  	} else {
  		afs_break_callback(vnode, afs_cb_break_for_unlink);

  		if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
  			_debug("AFS_VNODE_DELETED");

  		ret = afs_validate(vnode, op->key);
  		if (ret != -ESTALE)
  			op->error = ret;

  	}

  	_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, op->error);
  }
  
  static void afs_unlink_success(struct afs_operation *op)
  {
  	_enter("op=%08x", op->debug_id);

  	op->ctime = op->file[0].scb.status.mtime_client;

  	afs_check_dir_conflict(op, &op->file[0]);

  	afs_vnode_commit_status(op, &op->file[0]);
  	afs_vnode_commit_status(op, &op->file[1]);
  	afs_update_dentry_version(op, &op->file[0], op->dentry);
  	afs_dir_remove_link(op);
  }
  
  static void afs_unlink_edit_dir(struct afs_operation *op)
  {
  	struct afs_vnode_param *dvp = &op->file[0];
  	struct afs_vnode *dvnode = dvp->vnode;
  
  	_enter("op=%08x", op->debug_id);
  	down_write(&dvnode->validate_lock);
  	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  	    dvnode->status.data_version == dvp->dv_before + dvp->dv_delta)
  		afs_edit_dir_remove(dvnode, &op->dentry->d_name,
  				    afs_edit_dir_for_unlink);
  	up_write(&dvnode->validate_lock);

  }

  static void afs_unlink_put(struct afs_operation *op)
  {
  	_enter("op=%08x", op->debug_id);
  	if (op->unlink.need_rehash && op->error < 0 && op->error != -ENOENT)
  		d_rehash(op->dentry);
  }
  
  static const struct afs_operation_ops afs_unlink_operation = {
  	.issue_afs_rpc	= afs_fs_remove_file,
  	.issue_yfs_rpc	= yfs_fs_remove_file,
  	.success	= afs_unlink_success,

  	.aborted	= afs_check_for_remote_deletion,

  	.edit_dir	= afs_unlink_edit_dir,
  	.put		= afs_unlink_put,
  };

  /*
   * Remove a file or symlink from an AFS filesystem.

   */
  static int afs_unlink(struct inode *dir, struct dentry *dentry)
  {

  	struct afs_operation *op;

  	struct afs_vnode *dvnode = AFS_FS_I(dir);
  	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));

  	int ret;

  	_enter("{%llx:%llu},{%pd}",

  	       dvnode->fid.vid, dvnode->fid.vnode, dentry);

  	if (dentry->d_name.len >= AFSNAMEMAX)

  		return -ENAMETOOLONG;

  	op = afs_alloc_operation(NULL, dvnode->volume);
  	if (IS_ERR(op))
  		return PTR_ERR(op);

  	afs_op_set_vnode(op, 0, dvnode);
  	op->file[0].dv_delta = 1;

  	op->file[0].update_ctime = true;

  	/* Try to make sure we have a callback promise on the victim. */

  	ret = afs_validate(vnode, op->key);
  	if (ret < 0) {
  		op->error = ret;
  		goto error;
  	}

  	spin_lock(&dentry->d_lock);

  	if (d_count(dentry) > 1) {

  		spin_unlock(&dentry->d_lock);
  		/* Start asynchronous writeout of the inode */
  		write_inode_now(d_inode(dentry), 0);

  		op->error = afs_sillyrename(dvnode, vnode, dentry, op->key);
  		goto error;

  	}
  	if (!d_unhashed(dentry)) {
  		/* Prevent a race with RCU lookup. */
  		__d_drop(dentry);

  		op->unlink.need_rehash = true;

  	}
  	spin_unlock(&dentry->d_lock);

  	op->file[1].vnode = vnode;

  	op->file[1].update_ctime = true;

  	op->file[1].op_unlinked = true;

  	op->dentry	= dentry;
  	op->ops		= &afs_unlink_operation;

  	afs_begin_vnode_operation(op);
  	afs_wait_for_operation(op);
  
  	/* If there was a conflict with a third party, check the status of the
  	 * unlinked vnode.
  	 */
  	if (op->error == 0 && (op->flags & AFS_OPERATION_DIR_CONFLICT)) {
  		op->file[1].update_ctime = false;
  		op->fetch_status.which = 1;
  		op->ops = &afs_fetch_status_operation;
  		afs_begin_vnode_operation(op);
  		afs_wait_for_operation(op);
  	}
  
  	return afs_put_operation(op);

  error:

  	return afs_put_operation(op);

  }

  static const struct afs_operation_ops afs_create_operation = {
  	.issue_afs_rpc	= afs_fs_create_file,
  	.issue_yfs_rpc	= yfs_fs_create_file,
  	.success	= afs_create_success,

  	.aborted	= afs_check_for_remote_deletion,

  	.edit_dir	= afs_create_edit_dir,
  	.put		= afs_create_put,
  };

  /*
   * 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_operation *op;

  	struct afs_vnode *dvnode = AFS_FS_I(dir);

  	int ret = -ENAMETOOLONG;

  	_enter("{%llx:%llu},{%pd},%ho",

  	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);

  	if (dentry->d_name.len >= AFSNAMEMAX)
  		goto error;

  	op = afs_alloc_operation(NULL, dvnode->volume);
  	if (IS_ERR(op)) {
  		ret = PTR_ERR(op);