diff options
Diffstat (limited to 'drivers/staging/vboxsf/file.c')
-rw-r--r-- | drivers/staging/vboxsf/file.c | 370 |
1 files changed, 0 insertions, 370 deletions
diff --git a/drivers/staging/vboxsf/file.c b/drivers/staging/vboxsf/file.c deleted file mode 100644 index 4b61ccf83fca..000000000000 --- a/drivers/staging/vboxsf/file.c +++ /dev/null @@ -1,370 +0,0 @@ -// SPDX-License-Identifier: MIT -/* - * VirtualBox Guest Shared Folders support: Regular file inode and file ops. - * - * Copyright (C) 2006-2018 Oracle Corporation - */ - -#include <linux/mm.h> -#include <linux/page-flags.h> -#include <linux/pagemap.h> -#include <linux/highmem.h> -#include <linux/sizes.h> -#include "vfsmod.h" - -struct vboxsf_handle { - u64 handle; - u32 root; - u32 access_flags; - struct kref refcount; - struct list_head head; -}; - -static int vboxsf_file_open(struct inode *inode, struct file *file) -{ - struct vboxsf_inode *sf_i = VBOXSF_I(inode); - struct shfl_createparms params = {}; - struct vboxsf_handle *sf_handle; - u32 access_flags = 0; - int err; - - sf_handle = kmalloc(sizeof(*sf_handle), GFP_KERNEL); - if (!sf_handle) - return -ENOMEM; - - /* - * We check the value of params.handle afterwards to find out if - * the call succeeded or failed, as the API does not seem to cleanly - * distinguish error and informational messages. - * - * Furthermore, we must set params.handle to SHFL_HANDLE_NIL to - * make the shared folders host service use our mode parameter. - */ - params.handle = SHFL_HANDLE_NIL; - if (file->f_flags & O_CREAT) { - params.create_flags |= SHFL_CF_ACT_CREATE_IF_NEW; - /* - * We ignore O_EXCL, as the Linux kernel seems to call create - * beforehand itself, so O_EXCL should always fail. - */ - if (file->f_flags & O_TRUNC) - params.create_flags |= SHFL_CF_ACT_OVERWRITE_IF_EXISTS; - else - params.create_flags |= SHFL_CF_ACT_OPEN_IF_EXISTS; - } else { - params.create_flags |= SHFL_CF_ACT_FAIL_IF_NEW; - if (file->f_flags & O_TRUNC) - params.create_flags |= SHFL_CF_ACT_OVERWRITE_IF_EXISTS; - } - - switch (file->f_flags & O_ACCMODE) { - case O_RDONLY: - access_flags |= SHFL_CF_ACCESS_READ; - break; - - case O_WRONLY: - access_flags |= SHFL_CF_ACCESS_WRITE; - break; - - case O_RDWR: - access_flags |= SHFL_CF_ACCESS_READWRITE; - break; - - default: - WARN_ON(1); - } - - if (file->f_flags & O_APPEND) - access_flags |= SHFL_CF_ACCESS_APPEND; - - params.create_flags |= access_flags; - params.info.attr.mode = inode->i_mode; - - err = vboxsf_create_at_dentry(file_dentry(file), ¶ms); - if (err == 0 && params.handle == SHFL_HANDLE_NIL) - err = (params.result == SHFL_FILE_EXISTS) ? -EEXIST : -ENOENT; - if (err) { - kfree(sf_handle); - return err; - } - - /* the host may have given us different attr then requested */ - sf_i->force_restat = 1; - - /* init our handle struct and add it to the inode's handles list */ - sf_handle->handle = params.handle; - sf_handle->root = VBOXSF_SBI(inode->i_sb)->root; - sf_handle->access_flags = access_flags; - kref_init(&sf_handle->refcount); - - mutex_lock(&sf_i->handle_list_mutex); - list_add(&sf_handle->head, &sf_i->handle_list); - mutex_unlock(&sf_i->handle_list_mutex); - - file->private_data = sf_handle; - return 0; -} - -static void vboxsf_handle_release(struct kref *refcount) -{ - struct vboxsf_handle *sf_handle = - container_of(refcount, struct vboxsf_handle, refcount); - - vboxsf_close(sf_handle->root, sf_handle->handle); - kfree(sf_handle); -} - -static int vboxsf_file_release(struct inode *inode, struct file *file) -{ - struct vboxsf_inode *sf_i = VBOXSF_I(inode); - struct vboxsf_handle *sf_handle = file->private_data; - - /* - * When a file is closed on our (the guest) side, we want any subsequent - * accesses done on the host side to see all changes done from our side. - */ - filemap_write_and_wait(inode->i_mapping); - - mutex_lock(&sf_i->handle_list_mutex); - list_del(&sf_handle->head); - mutex_unlock(&sf_i->handle_list_mutex); - - kref_put(&sf_handle->refcount, vboxsf_handle_release); - return 0; -} - -/* - * Write back dirty pages now, because there may not be any suitable - * open files later - */ -static void vboxsf_vma_close(struct vm_area_struct *vma) -{ - filemap_write_and_wait(vma->vm_file->f_mapping); -} - -static const struct vm_operations_struct vboxsf_file_vm_ops = { - .close = vboxsf_vma_close, - .fault = filemap_fault, - .map_pages = filemap_map_pages, -}; - -static int vboxsf_file_mmap(struct file *file, struct vm_area_struct *vma) -{ - int err; - - err = generic_file_mmap(file, vma); - if (!err) - vma->vm_ops = &vboxsf_file_vm_ops; - - return err; -} - -/* - * Note that since we are accessing files on the host's filesystem, files - * may always be changed underneath us by the host! - * - * The vboxsf API between the guest and the host does not offer any functions - * to deal with this. There is no inode-generation to check for changes, no - * events / callback on changes and no way to lock files. - * - * To avoid returning stale data when a file gets *opened* on our (the guest) - * side, we do a "stat" on the host side, then compare the mtime with the - * last known mtime and invalidate the page-cache if they differ. - * This is done from vboxsf_inode_revalidate(). - * - * When reads are done through the read_iter fop, it is possible to do - * further cache revalidation then, there are 3 options to deal with this: - * - * 1) Rely solely on the revalidation done at open time - * 2) Do another "stat" and compare mtime again. Unfortunately the vboxsf - * host API does not allow stat on handles, so we would need to use - * file->f_path.dentry and the stat will then fail if the file was unlinked - * or renamed (and there is no thing like NFS' silly-rename). So we get: - * 2a) "stat" and compare mtime, on stat failure invalidate the cache - * 2b) "stat" and compare mtime, on stat failure do nothing - * 3) Simply always call invalidate_inode_pages2_range on the range of the read - * - * Currently we are keeping things KISS and using option 1. this allows - * directly using generic_file_read_iter without wrapping it. - * - * This means that only data written on the host side before open() on - * the guest side is guaranteed to be seen by the guest. If necessary - * we may provide other read-cache strategies in the future and make this - * configurable through a mount option. - */ -const struct file_operations vboxsf_reg_fops = { - .llseek = generic_file_llseek, - .read_iter = generic_file_read_iter, - .write_iter = generic_file_write_iter, - .mmap = vboxsf_file_mmap, - .open = vboxsf_file_open, - .release = vboxsf_file_release, - .fsync = noop_fsync, - .splice_read = generic_file_splice_read, -}; - -const struct inode_operations vboxsf_reg_iops = { - .getattr = vboxsf_getattr, - .setattr = vboxsf_setattr -}; - -static int vboxsf_readpage(struct file *file, struct page *page) -{ - struct vboxsf_handle *sf_handle = file->private_data; - loff_t off = page_offset(page); - u32 nread = PAGE_SIZE; - u8 *buf; - int err; - - buf = kmap(page); - - err = vboxsf_read(sf_handle->root, sf_handle->handle, off, &nread, buf); - if (err == 0) { - memset(&buf[nread], 0, PAGE_SIZE - nread); - flush_dcache_page(page); - SetPageUptodate(page); - } else { - SetPageError(page); - } - - kunmap(page); - unlock_page(page); - return err; -} - -static struct vboxsf_handle *vboxsf_get_write_handle(struct vboxsf_inode *sf_i) -{ - struct vboxsf_handle *h, *sf_handle = NULL; - - mutex_lock(&sf_i->handle_list_mutex); - list_for_each_entry(h, &sf_i->handle_list, head) { - if (h->access_flags == SHFL_CF_ACCESS_WRITE || - h->access_flags == SHFL_CF_ACCESS_READWRITE) { - kref_get(&h->refcount); - sf_handle = h; - break; - } - } - mutex_unlock(&sf_i->handle_list_mutex); - - return sf_handle; -} - -static int vboxsf_writepage(struct page *page, struct writeback_control *wbc) -{ - struct inode *inode = page->mapping->host; - struct vboxsf_inode *sf_i = VBOXSF_I(inode); - struct vboxsf_handle *sf_handle; - loff_t off = page_offset(page); - loff_t size = i_size_read(inode); - u32 nwrite = PAGE_SIZE; - u8 *buf; - int err; - - if (off + PAGE_SIZE > size) - nwrite = size & ~PAGE_MASK; - - sf_handle = vboxsf_get_write_handle(sf_i); - if (!sf_handle) - return -EBADF; - - buf = kmap(page); - err = vboxsf_write(sf_handle->root, sf_handle->handle, - off, &nwrite, buf); - kunmap(page); - - kref_put(&sf_handle->refcount, vboxsf_handle_release); - - if (err == 0) { - ClearPageError(page); - /* mtime changed */ - sf_i->force_restat = 1; - } else { - ClearPageUptodate(page); - } - - unlock_page(page); - return err; -} - -static int vboxsf_write_end(struct file *file, struct address_space *mapping, - loff_t pos, unsigned int len, unsigned int copied, - struct page *page, void *fsdata) -{ - struct inode *inode = mapping->host; - struct vboxsf_handle *sf_handle = file->private_data; - unsigned int from = pos & ~PAGE_MASK; - u32 nwritten = len; - u8 *buf; - int err; - - buf = kmap(page); - err = vboxsf_write(sf_handle->root, sf_handle->handle, - pos, &nwritten, buf + from); - kunmap(page); - - if (err) { - nwritten = 0; - goto out; - } - - /* mtime changed */ - VBOXSF_I(inode)->force_restat = 1; - - if (!PageUptodate(page) && nwritten == PAGE_SIZE) - SetPageUptodate(page); - - pos += nwritten; - if (pos > inode->i_size) - i_size_write(inode, pos); - -out: - unlock_page(page); - put_page(page); - - return nwritten; -} - -const struct address_space_operations vboxsf_reg_aops = { - .readpage = vboxsf_readpage, - .writepage = vboxsf_writepage, - .set_page_dirty = __set_page_dirty_nobuffers, - .write_begin = simple_write_begin, - .write_end = vboxsf_write_end, -}; - -static const char *vboxsf_get_link(struct dentry *dentry, struct inode *inode, - struct delayed_call *done) -{ - struct vboxsf_sbi *sbi = VBOXSF_SBI(inode->i_sb); - struct shfl_string *path; - char *link; - int err; - - if (!dentry) - return ERR_PTR(-ECHILD); - - path = vboxsf_path_from_dentry(sbi, dentry); - if (IS_ERR(path)) - return (char *)path; - - link = kzalloc(PATH_MAX, GFP_KERNEL); - if (!link) { - __putname(path); - return ERR_PTR(-ENOMEM); - } - - err = vboxsf_readlink(sbi->root, path, PATH_MAX, link); - __putname(path); - if (err) { - kfree(link); - return ERR_PTR(err); - } - - set_delayed_call(done, kfree_link, link); - return link; -} - -const struct inode_operations vboxsf_lnk_iops = { - .get_link = vboxsf_get_link -}; |