text: // 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 inode		**inodes;
  	struct afs_status_cb	*statuses;
  	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\n",
  			       __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\n",
  		dvnode->fid.vid, dvnode->fid.vnode,
  		req->file_size, req->len, req->actual_len, req->remain);
  	pr_warn("DIR %llx %x %x %x\n",
  		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\n", 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;
  
  			set_page_private(req->pages[i], 1);
  			SetPagePrivate(req->pages[i]);
  			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[0].vnode	= ino;
  		cookie->fids[0].unique	= dtype;
  		cookie->found = 1;
  		if (cookie->one_only)
  			return -1;
  	}
  
  	ret = cookie->nr_fids >= 50 ? -1 : 0;
  	_leave(" = %d", ret);
  	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_cb_interest *dcbi, *cbi = NULL;
  	struct afs_super_info *as = dir->i_sb->s_fs_info;
  	struct afs_status_cb *scb;
  	struct afs_iget_data iget_data;
  	struct afs_fs_cursor fc;
  	struct afs_server *server;
  	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);
  	int ret, 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);
  
  	cookie->ctx.actor = afs_lookup_filldir;
  	cookie->name = dentry->d_name;
  	cookie->nr_fids = 1; /* slot 0 is saved for the fid we actually want */
  
  	read_seqlock_excl(&dvnode->cb_lock);
  	dcbi = rcu_dereference_protected(dvnode->cb_interest,
  					 lockdep_is_held(&dvnode->cb_lock.lock));
  	if (dcbi) {
  		server = dcbi->server;
  		if (server &&
  		    test_bit(AFS_SERVER_FL_NO_IBULK, &server->flags))
  			cookie->one_only = true;
  	}
  	read_sequnlock_excl(&dvnode->cb_lock);
  
  	for (i = 0; i < 50; i++)
  		cookie->fids[i].vid = as->volume->vid;
  
  	/* search the directory */
  	ret = afs_dir_iterate(dir, &cookie->ctx, key, &data_version);
  	if (ret < 0) {
  		inode = ERR_PTR(ret);
  		goto out;
  	}
  
  	dentry->d_fsdata = (void *)(unsigned long)data_version;
  
  	inode = ERR_PTR(-ENOENT);
  	if (!cookie->found)
  		goto out;
  
  	/* Check to see if we already have an inode for the primary fid. */
  	iget_data.fid = cookie->fids[0];
  	iget_data.volume = dvnode->volume;
  	iget_data.cb_v_break = dvnode->volume->cb_v_break;
  	iget_data.cb_s_break = 0;
  	inode = ilookup5(dir->i_sb, cookie->fids[0].vnode,
  			 afs_iget5_test, &iget_data);
  	if (inode)
  		goto out;
  
  	/* Need space for examining all the selected files */
  	inode = ERR_PTR(-ENOMEM);
  	cookie->statuses = kvcalloc(cookie->nr_fids, sizeof(struct afs_status_cb),
  				    GFP_KERNEL);
  	if (!cookie->statuses)
  		goto out;
  
  	cookie->inodes = kcalloc(cookie->nr_fids, sizeof(struct inode *),
  				 GFP_KERNEL);
  	if (!cookie->inodes)
  		goto out_s;
  
  	for (i = 1; i < cookie->nr_fids; i++) {
  		scb = &cookie->statuses[i];
  
  		/* Find any inodes that already exist and get their
  		 * callback counters.
  		 */
  		iget_data.fid = cookie->fids[i];
  		ti = ilookup5_nowait(dir->i_sb, iget_data.fid.vnode,
  				     afs_iget5_test, &iget_data);
  		if (!IS_ERR_OR_NULL(ti)) {
  			vnode = AFS_FS_I(ti);
  			scb->cb_break = afs_calc_vnode_cb_break(vnode);
  			cookie->inodes[i] = ti;
  		}
  	}
  
  	/* Try FS.InlineBulkStatus first.  Abort codes for the individual
  	 * lookups contained therein are stored in the reply without aborting
  	 * the whole operation.
  	 */
  	if (cookie->one_only)
  		goto no_inline_bulk_status;
  
  	inode = ERR_PTR(-ERESTARTSYS);
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		while (afs_select_fileserver(&fc)) {
  			if (test_bit(AFS_SERVER_FL_NO_IBULK,
  				      &fc.cbi->server->flags)) {
  				fc.ac.abort_code = RX_INVALID_OPERATION;
  				fc.ac.error = -ECONNABORTED;
  				break;
  			}
  			iget_data.cb_v_break = dvnode->volume->cb_v_break;
  			iget_data.cb_s_break = fc.cbi->server->cb_s_break;
  			afs_fs_inline_bulk_status(&fc,
  						  afs_v2net(dvnode),
  						  cookie->fids,
  						  cookie->statuses,
  						  cookie->nr_fids, NULL);
  		}
  
  		if (fc.ac.error == 0)
  			cbi = afs_get_cb_interest(fc.cbi);
  		if (fc.ac.abort_code == RX_INVALID_OPERATION)
  			set_bit(AFS_SERVER_FL_NO_IBULK, &fc.cbi->server->flags);
  		inode = ERR_PTR(afs_end_vnode_operation(&fc));
  	}
  
  	if (!IS_ERR(inode))
  		goto success;
  	if (fc.ac.abort_code != RX_INVALID_OPERATION)
  		goto out_c;
  
  no_inline_bulk_status:
  	/* 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 just the primary fid.
  	 */
  	inode = ERR_PTR(-ERESTARTSYS);
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		while (afs_select_fileserver(&fc)) {
  			iget_data.cb_v_break = dvnode->volume->cb_v_break;
  			iget_data.cb_s_break = fc.cbi->server->cb_s_break;
  			scb = &cookie->statuses[0];
  			afs_fs_fetch_status(&fc,
  					    afs_v2net(dvnode),
  					    cookie->fids,
  					    scb,
  					    NULL);
  		}
  
  		if (fc.ac.error == 0)
  			cbi = afs_get_cb_interest(fc.cbi);
  		inode = ERR_PTR(afs_end_vnode_operation(&fc));
  	}
  
  	if (IS_ERR(inode))
  		goto out_c;
  
  success:
  	/* Turn all the files into inodes and save the first one - which is the
  	 * one we actually want.
  	 */
  	scb = &cookie->statuses[0];
  	if (scb->status.abort_code != 0)
  		inode = ERR_PTR(afs_abort_to_error(scb->status.abort_code));
  
  	for (i = 0; i < cookie->nr_fids; i++) {
  		struct afs_status_cb *scb = &cookie->statuses[i];
  
  		if (!scb->have_status && !scb->have_error)
  			continue;
  
  		if (cookie->inodes[i]) {
  			struct afs_vnode *iv = AFS_FS_I(cookie->inodes[i]);
  
  			if (test_bit(AFS_VNODE_UNSET, &iv->flags))
  				continue;
  
  			afs_vnode_commit_status(&fc, iv,
  						scb->cb_break, NULL, scb);
  			continue;
  		}
  
  		if (scb->status.abort_code != 0)
  			continue;
  
  		iget_data.fid = cookie->fids[i];
  		ti = afs_iget(dir->i_sb, key, &iget_data, scb, cbi, dvnode);
  		if (!IS_ERR(ti))
  			afs_cache_permit(AFS_FS_I(ti), key,
  					 0 /* Assume vnode->cb_break is 0 */ +
  					 iget_data.cb_v_break,
  					 scb);
  		if (i == 0) {
  			inode = ti;
  		} else {
  			if (!IS_ERR(ti))
  				iput(ti);
  		}
  	}
  
  out_c:
  	afs_put_cb_interest(afs_v2net(dvnode), cbi);
  	if (cookie->inodes) {
  		for (i = 0; i < cookie->nr_fids; i++)
  			iput(cookie->inodes[i]);
  		kfree(cookie->inodes);
  	}
  out_s:
  	kvfree(cookie->statuses);
  out:
  	kfree(cookie);
  	return inode;
  }
  
  /*
   * 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;
  
  	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);
  	}
  	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 uninitialized_var(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\n",
  			       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);
  }
  
  /*
   * Create a new inode for create/mkdir/symlink
   */
  static void afs_vnode_new_inode(struct afs_fs_cursor *fc,
  				struct dentry *new_dentry,
  				struct afs_iget_data *new_data,
  				struct afs_status_cb *new_scb)
  {
  	struct afs_vnode *vnode;
  	struct inode *inode;
  
  	if (fc->ac.error < 0)
  		return;
  
  	inode = afs_iget(fc->vnode->vfs_inode.i_sb, fc->key,
  			 new_data, new_scb, fc->cbi, fc->vnode);
  	if (IS_ERR(inode)) {
  		/* ENOMEM or EINTR at a really inconvenient time - just abandon
  		 * the new directory on the server.
  		 */
  		fc->ac.error = PTR_ERR(inode);
  		return;
  	}
  
  	vnode = AFS_FS_I(inode);
  	set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
  	if (fc->ac.error == 0)
  		afs_cache_permit(vnode, fc->key, vnode->cb_break, new_scb);
  	d_instantiate(new_dentry, inode);
  }
  
  static void afs_prep_for_new_inode(struct afs_fs_cursor *fc,
  				   struct afs_iget_data *iget_data)
  {
  	iget_data->volume = fc->vnode->volume;
  	iget_data->cb_v_break = fc->vnode->volume->cb_v_break;
  	iget_data->cb_s_break = fc->cbi->server->cb_s_break;
  }
  
  /*
   * Note that a dentry got changed.  We need to set d_fsdata to the data version
   * number derived from the result of the operation.  It doesn't matter if
   * d_fsdata goes backwards as we'll just revalidate.
   */
  static void afs_update_dentry_version(struct afs_fs_cursor *fc,
  				      struct dentry *dentry,
  				      struct afs_status_cb *scb)
  {
  	if (fc->ac.error == 0)
  		dentry->d_fsdata =
  			(void *)(unsigned long)scb->status.data_version;
  }
  
  /*
   * create a directory on an AFS filesystem
   */
  static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
  {
  	struct afs_iget_data iget_data;
  	struct afs_status_cb *scb;
  	struct afs_fs_cursor fc;
  	struct afs_vnode *dvnode = AFS_FS_I(dir);
  	struct key *key;
  	afs_dataversion_t data_version;
  	int ret;
  
  	mode |= S_IFDIR;
  
  	_enter("{%llx:%llu},{%pd},%ho",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
  
  	ret = -ENOMEM;
  	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
  	if (!scb)
  		goto error;
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error_scb;
  	}
  
  	ret = -ERESTARTSYS;
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		data_version = dvnode->status.data_version + 1;
  
  		while (afs_select_fileserver(&fc)) {
  			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
  			afs_prep_for_new_inode(&fc, &iget_data);
  			afs_fs_create(&fc, dentry->d_name.name, mode,
  				      &scb[0], &iget_data.fid, &scb[1]);
  		}
  
  		afs_check_for_remote_deletion(&fc, dvnode);
  		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
  					&data_version, &scb[0]);
  		afs_update_dentry_version(&fc, dentry, &scb[0]);
  		afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
  		ret = afs_end_vnode_operation(&fc);
  		if (ret < 0)
  			goto error_key;
  	} else {
  		goto error_key;
  	}
  
  	if (ret == 0) {
  		down_write(&dvnode->validate_lock);
  		if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  		    dvnode->status.data_version == data_version)
  			afs_edit_dir_add(dvnode, &dentry->d_name, &iget_data.fid,
  					 afs_edit_dir_for_create);
  		up_write(&dvnode->validate_lock);
  	}
  
  	key_put(key);
  	kfree(scb);
  	_leave(" = 0");
  	return 0;
  
  error_key:
  	key_put(key);
  error_scb:
  	kfree(scb);
  error:
  	d_drop(dentry);
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * 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);
  	}
  }
  
  /*
   * remove a directory from an AFS filesystem
   */
  static int afs_rmdir(struct inode *dir, struct dentry *dentry)
  {
  	struct afs_status_cb *scb;
  	struct afs_fs_cursor fc;
  	struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode = NULL;
  	struct key *key;
  	afs_dataversion_t data_version;
  	int ret;
  
  	_enter("{%llx:%llu},{%pd}",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry);
  
  	scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL);
  	if (!scb)
  		return -ENOMEM;
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error;
  	}
  
  	/* 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, key);
  		if (ret < 0)
  			goto error_key;
  	}
  
  	if (vnode) {
  		ret = down_write_killable(&vnode->rmdir_lock);
  		if (ret < 0)
  			goto error_key;
  	}
  
  	ret = -ERESTARTSYS;
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		data_version = dvnode->status.data_version + 1;
  
  		while (afs_select_fileserver(&fc)) {
  			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
  			afs_fs_remove(&fc, vnode, dentry->d_name.name, true, scb);
  		}
  
  		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
  					&data_version, scb);
  		afs_update_dentry_version(&fc, dentry, scb);
  		ret = afs_end_vnode_operation(&fc);
  		if (ret == 0) {
  			afs_dir_remove_subdir(dentry);
  			down_write(&dvnode->validate_lock);
  			if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  			    dvnode->status.data_version == data_version)
  				afs_edit_dir_remove(dvnode, &dentry->d_name,
  						    afs_edit_dir_for_rmdir);
  			up_write(&dvnode->validate_lock);
  		}
  	}
  
  	if (vnode)
  		up_write(&vnode->rmdir_lock);
  error_key:
  	key_put(key);
  error:
  	kfree(scb);
  	return ret;
  }
  
  /*
   * 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 int afs_dir_remove_link(struct afs_vnode *dvnode, struct dentry *dentry,
  			       struct key *key)
  {
  	int ret = 0;
  
  	if (d_really_is_positive(dentry)) {
  		struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
  
  		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);
  			ret = 0;
  		} else {
  			afs_break_callback(vnode, afs_cb_break_for_unlink);
  
  			if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
  				kdebug("AFS_VNODE_DELETED");
  
  			ret = afs_validate(vnode, key);
  			if (ret == -ESTALE)
  				ret = 0;
  		}
  		_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
  	}
  
  	return ret;
  }
  
  /*
   * Remove a file or symlink from an AFS filesystem.
   */
  static int afs_unlink(struct inode *dir, struct dentry *dentry)
  {
  	struct afs_fs_cursor fc;
  	struct afs_status_cb *scb;
  	struct afs_vnode *dvnode = AFS_FS_I(dir);
  	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
  	struct key *key;
  	bool need_rehash = false;
  	int ret;
  
  	_enter("{%llx:%llu},{%pd}",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry);
  
  	if (dentry->d_name.len >= AFSNAMEMAX)
  		return -ENAMETOOLONG;
  
  	ret = -ENOMEM;
  	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
  	if (!scb)
  		goto error;
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error_scb;
  	}
  
  	/* Try to make sure we have a callback promise on the victim. */
  	ret = afs_validate(vnode, key);
  	if (ret < 0)
  		goto error_key;
  
  	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);
  		ret = afs_sillyrename(dvnode, vnode, dentry, key);
  		goto error_key;
  	}
  	if (!d_unhashed(dentry)) {
  		/* Prevent a race with RCU lookup. */
  		__d_drop(dentry);
  		need_rehash = true;
  	}
  	spin_unlock(&dentry->d_lock);
  
  	ret = -ERESTARTSYS;
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		afs_dataversion_t data_version = dvnode->status.data_version + 1;
  		afs_dataversion_t data_version_2 = vnode->status.data_version;
  
  		while (afs_select_fileserver(&fc)) {
  			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
  			fc.cb_break_2 = afs_calc_vnode_cb_break(vnode);
  
  			if (test_bit(AFS_SERVER_FL_IS_YFS, &fc.cbi->server->flags) &&
  			    !test_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags)) {
  				yfs_fs_remove_file2(&fc, vnode, dentry->d_name.name,
  						    &scb[0], &scb[1]);
  				if (fc.ac.error != -ECONNABORTED ||
  				    fc.ac.abort_code != RXGEN_OPCODE)
  					continue;
  				set_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags);
  			}
  
  			afs_fs_remove(&fc, vnode, dentry->d_name.name, false, &scb[0]);
  		}
  
  		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
  					&data_version, &scb[0]);
  		afs_vnode_commit_status(&fc, vnode, fc.cb_break_2,
  					&data_version_2, &scb[1]);
  		afs_update_dentry_version(&fc, dentry, &scb[0]);
  		ret = afs_end_vnode_operation(&fc);
  		if (ret == 0 && !(scb[1].have_status || scb[1].have_error))
  			ret = afs_dir_remove_link(dvnode, dentry, key);
  
  		if (ret == 0) {
  			down_write(&dvnode->validate_lock);
  			if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  			    dvnode->status.data_version == data_version)
  				afs_edit_dir_remove(dvnode, &dentry->d_name,
  						    afs_edit_dir_for_unlink);
  			up_write(&dvnode->validate_lock);
  		}
  	}
  
  	if (need_rehash && ret < 0 && ret != -ENOENT)
  		d_rehash(dentry);
  
  error_key:
  	key_put(key);
  error_scb:
  	kfree(scb);
  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_iget_data iget_data;
  	struct afs_fs_cursor fc;
  	struct afs_status_cb *scb;
  	struct afs_vnode *dvnode = AFS_FS_I(dir);
  	struct key *key;
  	afs_dataversion_t data_version;
  	int ret;
  
  	mode |= S_IFREG;
  
  	_enter("{%llx:%llu},{%pd},%ho,",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
  
  	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;
  	}
  
  	ret = -ENOMEM;
  	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
  	if (!scb)
  		goto error_scb;
  
  	ret = -ERESTARTSYS;
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		data_version = dvnode->status.data_version + 1;
  
  		while (afs_select_fileserver(&fc)) {
  			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
  			afs_prep_for_new_inode(&fc, &iget_data);
  			afs_fs_create(&fc, dentry->d_name.name, mode,
  				      &scb[0], &iget_data.fid, &scb[1]);
  		}
  
  		afs_check_for_remote_deletion(&fc, dvnode);
  		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
  					&data_version, &scb[0]);
  		afs_update_dentry_version(&fc, dentry, &scb[0]);
  		afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
  		ret = afs_end_vnode_operation(&fc);
  		if (ret < 0)
  			goto error_key;
  	} else {
  		goto error_key;
  	}
  
  	down_write(&dvnode->validate_lock);
  	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  	    dvnode->status.data_version == data_version)
  		afs_edit_dir_add(dvnode, &dentry->d_name, &iget_data.fid,
  				 afs_edit_dir_for_create);
  	up_write(&dvnode->validate_lock);
  
  	kfree(scb);
  	key_put(key);
  	_leave(" = 0");
  	return 0;
  
  error_scb:
  	kfree(scb);
  error_key:
  	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_fs_cursor fc;
  	struct afs_status_cb *scb;
  	struct afs_vnode *dvnode = AFS_FS_I(dir);
  	struct afs_vnode *vnode = AFS_FS_I(d_inode(from));
  	struct key *key;
  	afs_dataversion_t data_version;
  	int ret;
  
  	_enter("{%llx:%llu},{%llx:%llu},{%pd}",
  	       vnode->fid.vid, vnode->fid.vnode,
  	       dvnode->fid.vid, dvnode->fid.vnode,
  	       dentry);
  
  	ret = -ENAMETOOLONG;
  	if (dentry->d_name.len >= AFSNAMEMAX)
  		goto error;
  
  	ret = -ENOMEM;
  	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
  	if (!scb)
  		goto error;
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error_scb;
  	}
  
  	ret = -ERESTARTSYS;
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		data_version = dvnode->status.data_version + 1;
  
  		if (mutex_lock_interruptible_nested(&vnode->io_lock, 1) < 0) {
  			afs_end_vnode_operation(&fc);
  			goto error_key;
  		}
  
  		while (afs_select_fileserver(&fc)) {
  			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
  			fc.cb_break_2 = afs_calc_vnode_cb_break(vnode);
  			afs_fs_link(&fc, vnode, dentry->d_name.name,
  				    &scb[0], &scb[1]);
  		}
  
  		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
  					&data_version, &scb[0]);
  		afs_vnode_commit_status(&fc, vnode, fc.cb_break_2,
  					NULL, &scb[1]);
  		ihold(&vnode->vfs_inode);
  		afs_update_dentry_version(&fc, dentry, &scb[0]);
  		d_instantiate(dentry, &vnode->vfs_inode);
  
  		mutex_unlock(&vnode->io_lock);
  		ret = afs_end_vnode_operation(&fc);
  		if (ret < 0)
  			goto error_key;
  	} else {
  		goto error_key;
  	}
  
  	down_write(&dvnode->validate_lock);
  	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  	    dvnode->status.data_version == data_version)
  		afs_edit_dir_add(dvnode, &dentry->d_name, &vnode->fid,
  				 afs_edit_dir_for_link);
  	up_write(&dvnode->validate_lock);
  
  	key_put(key);
  	kfree(scb);
  	_leave(" = 0");
  	return 0;
  
  error_key:
  	key_put(key);
  error_scb:
  	kfree(scb);
  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_iget_data iget_data;
  	struct afs_fs_cursor fc;
  	struct afs_status_cb *scb;
  	struct afs_vnode *dvnode = AFS_FS_I(dir);
  	struct key *key;
  	afs_dataversion_t data_version;
  	int ret;
  
  	_enter("{%llx:%llu},{%pd},%s",
  	       dvnode->fid.vid, dvnode->fid.vnode, dentry,
  	       content);
  
  	ret = -ENAMETOOLONG;
  	if (dentry->d_name.len >= AFSNAMEMAX)
  		goto error;
  
  	ret = -EINVAL;
  	if (strlen(content) >= AFSPATHMAX)
  		goto error;
  
  	ret = -ENOMEM;
  	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
  	if (!scb)
  		goto error;
  
  	key = afs_request_key(dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error_scb;
  	}
  
  	ret = -ERESTARTSYS;
  	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
  		data_version = dvnode->status.data_version + 1;
  
  		while (afs_select_fileserver(&fc)) {
  			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
  			afs_prep_for_new_inode(&fc, &iget_data);
  			afs_fs_symlink(&fc, dentry->d_name.name, content,
  				       &scb[0], &iget_data.fid, &scb[1]);
  		}
  
  		afs_check_for_remote_deletion(&fc, dvnode);
  		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
  					&data_version, &scb[0]);
  		afs_update_dentry_version(&fc, dentry, &scb[0]);
  		afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
  		ret = afs_end_vnode_operation(&fc);
  		if (ret < 0)
  			goto error_key;
  	} else {
  		goto error_key;
  	}
  
  	down_write(&dvnode->validate_lock);
  	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
  	    dvnode->status.data_version == data_version)
  		afs_edit_dir_add(dvnode, &dentry->d_name, &iget_data.fid,
  				 afs_edit_dir_for_symlink);
  	up_write(&dvnode->validate_lock);
  
  	key_put(key);
  	kfree(scb);
  	_leave(" = 0");
  	return 0;
  
  error_key:
  	key_put(key);
  error_scb:
  	kfree(scb);
  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,
  		      unsigned int flags)
  {
  	struct afs_fs_cursor fc;
  	struct afs_status_cb *scb;
  	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
  	struct dentry *tmp = NULL, *rehash = NULL;
  	struct inode *new_inode;
  	struct key *key;
  	afs_dataversion_t orig_data_version;
  	afs_dataversion_t new_data_version;
  	bool new_negative = d_is_negative(new_dentry);
  	int ret;
  
  	if (flags)
  		return -EINVAL;
  
  	/* Don't allow silly-rename files be moved around. */
  	if (old_dentry->d_flags & DCACHE_NFSFS_RENAMED)
  		return -EINVAL;
  
  	vnode = AFS_FS_I(d_inode(old_dentry));
  	orig_dvnode = AFS_FS_I(old_dir);
  	new_dvnode = AFS_FS_I(new_dir);
  
  	_enter("{%llx:%llu},{%llx:%llu},{%llx:%llu},{%pd}",
  	       orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
  	       vnode->fid.vid, vnode->fid.vnode,
  	       new_dvnode->fid.vid, new_dvnode->fid.vnode,
  	       new_dentry);
  
  	ret = -ENOMEM;
  	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
  	if (!scb)
  		goto error;
  
  	key = afs_request_key(orig_dvnode->volume->cell);
  	if (IS_ERR(key)) {
  		ret = PTR_ERR(key);
  		goto error_scb;
  	}
  
  	/* For non-directories, check whether the target is busy and if so,
  	 * 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 (d_is_positive(new_dentry) && !d_is_dir(new_dentry)) {
  		/* To prevent any new references to the target during the
  		 * rename, we unhash the dentry in advance.
  		 */
  		if (!d_unhashed(new_dentry)) {
  			d_drop(new_dentry);
  			rehash = new_dentry;
  		}
  
  		if (d_count(new_dentry) > 2) {
  			/* copy the target dentry's name */
  			ret = -ENOMEM;
  			tmp = d_alloc(new_dentry->d_parent,
  				      &new_dentry->d_name);
  			if (!tmp)
  				goto error_rehash;
  
  			ret = afs_sillyrename(new_dvnode,
  					      AFS_FS_I(d_inode(new_dentry)),
  					      new_dentry, key);
  			if (ret)
  				goto error_rehash;
  
  			new_dentry = tmp;
  			rehash = NULL;
  			new_negative = true;
  		}
  	}
  
  	/* This bit is potentially nasty as there's a potential race with
  	 * afs_d_revalidate{,_rcu}().  We have to change d_fsdata on the dentry
  	 * to reflect it's new parent's new data_version after the op, but
  	 * d_revalidate may see old_dentry between the op having taken place
  	 * and the version being updated.
  	 *
  	 * So drop the old_dentry for now to make other threads go through
  	 * lookup instead - which we hold a lock against.
  	 */
  	d_drop(old_dentry);
  
  	ret = -ERESTARTSYS;
  	if (afs_begin_vnode_operation(&fc, orig_dvnode, key, true)) {
  		orig_data_version = orig_dvnode->status.data_version + 1;
  
  		if (orig_dvnode != new_dvnode) {
  			if (mutex_lock_interruptible_nested(&new_dvnode->io_lock, 1) < 0) {
  				afs_end_vnode_operation(&fc);
  				goto error_rehash_old;
  			}
  			new_data_version = new_dvnode->status.data_version + 1;
  		} else {
  			new_data_version = orig_data_version;
  		}
  
  		while (afs_select_fileserver(&fc)) {
  			fc.cb_break = afs_calc_vnode_cb_break(orig_dvnode);
  			fc.cb_break_2 = afs_calc_vnode_cb_break(new_dvnode);
  			afs_fs_rename(&fc, old_dentry->d_name.name,
  				      new_dvnode, new_dentry->d_name.name,
  				      &scb[0], &scb[1]);
  		}
  
  		afs_vnode_commit_status(&fc, orig_dvnode, fc.cb_break,
  					&orig_data_version, &scb[0]);
  		if (new_dvnode != orig_dvnode) {
  			afs_vnode_commit_status(&fc, new_dvnode, fc.cb_break_2,
  						&new_data_version, &scb[1]);
  			mutex_unlock(&new_dvnode->io_lock);
  		}
  		ret = afs_end_vnode_operation(&fc);
  		if (ret < 0)
  			goto error_rehash_old;
  	}
  
  	if (ret == 0) {
  		if (rehash)
  			d_rehash(rehash);
  		down_write(&orig_dvnode->validate_lock);
  		if (test_bit(AFS_VNODE_DIR_VALID, &orig_dvnode->flags) &&
  		    orig_dvnode->status.data_version == orig_data_version)
  			afs_edit_dir_remove(orig_dvnode, &old_dentry->d_name,
  					    afs_edit_dir_for_rename_0);
  		if (orig_dvnode != new_dvnode) {
  			up_write(&orig_dvnode->validate_lock);
  
  			down_write(&new_dvnode->validate_lock);
  		}
  		if (test_bit(AFS_VNODE_DIR_VALID, &new_dvnode->flags) &&
  		    orig_dvnode->status.data_version == new_data_version) {
  			if (!new_negative)
  				afs_edit_dir_remove(new_dvnode, &new_dentry->d_name,
  						    afs_edit_dir_for_rename_1);
  
  			afs_edit_dir_add(new_dvnode, &new_dentry->d_name,
  					 &vnode->fid, afs_edit_dir_for_rename_2);
  		}
  
  		new_inode = d_inode(new_dentry);
  		if (new_inode) {
  			spin_lock(&new_inode->i_lock);
  			if (new_inode->i_nlink > 0)
  				drop_nlink(new_inode);
  			spin_unlock(&new_inode->i_lock);
  		}
  
  		/* Now we can update d_fsdata on the dentries to reflect their
  		 * new parent's data_version.
  		 *
  		 * Note that if we ever implement RENAME_EXCHANGE, we'll have
  		 * to update both dentries with opposing dir versions.
  		 */
  		afs_update_dentry_version(&fc, old_dentry, &scb[1]);
  		afs_update_dentry_version(&fc, new_dentry, &scb[1]);
  		d_move(old_dentry, new_dentry);
  		up_write(&new_dvnode->validate_lock);
  		goto error_tmp;
  	}
  
  error_rehash_old:
  	d_rehash(new_dentry);
  error_rehash:
  	if (rehash)
  		d_rehash(rehash);
  error_tmp:
  	if (tmp)
  		dput(tmp);
  	key_put(key);
  error_scb:
  	kfree(scb);
  error:
  	_leave(" = %d", ret);
  	return ret;
  }
  
  /*
   * Release a directory page and clean up its private state if it's not busy
   * - return true if the page can now be released, false if not
   */
  static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags)
  {
  	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
  
  	_enter("{{%llx:%llu}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, page->index);
  
  	set_page_private(page, 0);
  	ClearPagePrivate(page);
  
  	/* The directory will need reloading. */
  	if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
  		afs_stat_v(dvnode, n_relpg);
  	return 1;
  }
  
  /*
   * invalidate part or all of a page
   * - release a page and clean up its private data if offset is 0 (indicating
   *   the entire page)
   */
  static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
  				   unsigned int length)
  {
  	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
  
  	_enter("{%lu},%u,%u", page->index, offset, length);
  
  	BUG_ON(!PageLocked(page));
  
  	/* The directory will need reloading. */
  	if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
  		afs_stat_v(dvnode, n_inval);
  
  	/* we clean up only if the entire page is being invalidated */
  	if (offset == 0 && length == PAGE_SIZE) {
  		set_page_private(page, 0);
  		ClearPagePrivate(page);
  	}
  }
  