1 // SPDX-License-Identifier: MIT
3  * VirtualBox Guest Shared Folders support: Regular file inode and file ops.
5  * Copyright (C) 2006-2018 Oracle Corporation
9 #include <linux/page-flags.h>
31 		return ERR_PTR(-ENOMEM);  in vboxsf_create_sf_handle()
34 	sf_i->force_restat = 1;  in vboxsf_create_sf_handle()
37 	sf_handle->handle = handle;  in vboxsf_create_sf_handle()
38 	sf_handle->root = VBOXSF_SBI(inode->i_sb)->root;  in vboxsf_create_sf_handle()
39 	sf_handle->access_flags = access_flags;  in vboxsf_create_sf_handle()
40 	kref_init(&sf_handle->refcount);  in vboxsf_create_sf_handle()
42 	mutex_lock(&sf_i->handle_list_mutex);  in vboxsf_create_sf_handle()
43 	list_add(&sf_handle->head, &sf_i->handle_list);  in vboxsf_create_sf_handle()
44 	mutex_unlock(&sf_i->handle_list_mutex);  in vboxsf_create_sf_handle()
51 	struct vboxsf_sbi *sbi = VBOXSF_SBI(inode->i_sb);  in vboxsf_file_open()
66 	if (file->f_flags & O_CREAT) {  in vboxsf_file_open()
72 		if (file->f_flags & O_TRUNC)  in vboxsf_file_open()
78 		if (file->f_flags & O_TRUNC)  in vboxsf_file_open()
82 	switch (file->f_flags & O_ACCMODE) {  in vboxsf_file_open()
99 	if (file->f_flags & O_APPEND)  in vboxsf_file_open()
103 	params.info.attr.mode = inode->i_mode;  in vboxsf_file_open()
107 		err = (params.result == SHFL_FILE_EXISTS) ? -EEXIST : -ENOENT;  in vboxsf_file_open()
113 		vboxsf_close(sbi->root, params.handle);  in vboxsf_file_open()
117 	file->private_data = sf_handle;  in vboxsf_file_open()
126 	vboxsf_close(sf_handle->root, sf_handle->handle);  in vboxsf_handle_release()
134 	mutex_lock(&sf_i->handle_list_mutex);  in vboxsf_release_sf_handle()
135 	list_del(&sf_handle->head);  in vboxsf_release_sf_handle()
136 	mutex_unlock(&sf_i->handle_list_mutex);  in vboxsf_release_sf_handle()
138 	kref_put(&sf_handle->refcount, vboxsf_handle_release);  in vboxsf_release_sf_handle()
144 	 * When a file is closed on our (the guest) side, we want any subsequent  in vboxsf_file_release()
145 	 * accesses done on the host side to see all changes done from our side.  in vboxsf_file_release()
147 	filemap_write_and_wait(inode->i_mapping);  in vboxsf_file_release()
149 	vboxsf_release_sf_handle(inode, file->private_data);  in vboxsf_file_release()
159 	filemap_write_and_wait(vma->vm_file->f_mapping);  in vboxsf_vma_close()
174 		vma->vm_ops = &vboxsf_file_vm_ops;  in vboxsf_file_mmap()
183  * The vboxsf API between the guest and the host does not offer any functions
184  * to deal with this. There is no inode-generation to check for changes, no
187  * To avoid returning stale data when a file gets *opened* on our (the guest)
188  * side, we do a "stat" on the host side, then compare the mtime with the
189  * last known mtime and invalidate the page-cache if they differ.
198  *     file->f_path.dentry and the stat will then fail if the file was unlinked
199  *     or renamed (and there is no thing like NFS' silly-rename). So we get:
207  * This means that only data written on the host side before open() on
208  * the guest side is guaranteed to be seen by the guest. If necessary
209  * we may provide other read-cache strategies in the future and make this
231 	struct vboxsf_handle *sf_handle = file->private_data;  in vboxsf_read_folio()
239 	err = vboxsf_read(sf_handle->root, sf_handle->handle, off, &nread, buf);  in vboxsf_read_folio()
251 	mutex_lock(&sf_i->handle_list_mutex);  in vboxsf_get_write_handle()
252 	list_for_each_entry(h, &sf_i->handle_list, head) {  in vboxsf_get_write_handle()
253 		if (h->access_flags == SHFL_CF_ACCESS_WRITE ||  in vboxsf_get_write_handle()
254 		    h->access_flags == SHFL_CF_ACCESS_READWRITE) {  in vboxsf_get_write_handle()
255 			kref_get(&h->refcount);  in vboxsf_get_write_handle()
260 	mutex_unlock(&sf_i->handle_list_mutex);  in vboxsf_get_write_handle()
267 	struct inode *inode = page->mapping->host;  in vboxsf_writepage()
281 		return -EBADF;  in vboxsf_writepage()
284 	err = vboxsf_write(sf_handle->root, sf_handle->handle,  in vboxsf_writepage()
288 	kref_put(&sf_handle->refcount, vboxsf_handle_release);  in vboxsf_writepage()
292 		sf_i->force_restat = 1;  in vboxsf_writepage()
305 	struct inode *inode = mapping->host;  in vboxsf_write_end()
306 	struct vboxsf_handle *sf_handle = file->private_data;  in vboxsf_write_end()
314 		folio_zero_range(folio, from + copied, len - copied);  in vboxsf_write_end()
316 	buf = kmap(&folio->page);  in vboxsf_write_end()
317 	err = vboxsf_write(sf_handle->root, sf_handle->handle,  in vboxsf_write_end()
319 	kunmap(&folio->page);  in vboxsf_write_end()
327 	VBOXSF_I(inode)->force_restat = 1;  in vboxsf_write_end()
333 	if (pos > inode->i_size)  in vboxsf_write_end()
359 	struct vboxsf_sbi *sbi = VBOXSF_SBI(inode->i_sb);  in vboxsf_get_link()
365 		return ERR_PTR(-ECHILD);  in vboxsf_get_link()
374 		return ERR_PTR(-ENOMEM);  in vboxsf_get_link()
377 	err = vboxsf_readlink(sbi->root, path, PATH_MAX, link);  in vboxsf_get_link()