vfsmod.c revision c161379f4055372228230517aa1700c47e3b9b7f
6a67d144095c31bbafed93cec1619590157335eajvergara * vboxsf -- VirtualBox Guest Additions for Linux:
6a67d144095c31bbafed93cec1619590157335eajvergara * Virtual File System for VirtualBox Shared Folders
6a67d144095c31bbafed93cec1619590157335eajvergara * Superblock reading
6a67d144095c31bbafed93cec1619590157335eajvergara * Few utility functions
6a67d144095c31bbafed93cec1619590157335eajvergara * Copyright (C) 2006-2010 Oracle Corporation
6a67d144095c31bbafed93cec1619590157335eajvergara * This file is part of VirtualBox Open Source Edition (OSE), as
6a67d144095c31bbafed93cec1619590157335eajvergara * available from http://www.virtualbox.org. This file is free software;
6a67d144095c31bbafed93cec1619590157335eajvergara * you can redistribute it and/or modify it under the terms of the GNU
6a67d144095c31bbafed93cec1619590157335eajvergara * General Public License (GPL) as published by the Free Software
6a67d144095c31bbafed93cec1619590157335eajvergara * Foundation, in version 2 as it comes in the "COPYING" file of the
6a67d144095c31bbafed93cec1619590157335eajvergara * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
6a67d144095c31bbafed93cec1619590157335eajvergara * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
6a67d144095c31bbafed93cec1619590157335eajvergara * @note Anyone wishing to make changes here might wish to take a look at
6a67d144095c31bbafed93cec1619590157335eajvergara * http://www.atnf.csiro.au/people/rgooch/linux/vfs.txt
6a67d144095c31bbafed93cec1619590157335eajvergara * which seems to be the closest there is to official documentation on
6a67d144095c31bbafed93cec1619590157335eajvergara * writing filesystem drivers for Linux.
6a67d144095c31bbafed93cec1619590157335eajvergaraMODULE_DESCRIPTION(VBOX_PRODUCT " VFS Module for Host File System Access");
6a67d144095c31bbafed93cec1619590157335eajvergaraMODULE_VERSION(VBOX_VERSION_STRING " (interface " RT_XSTR(VMMDEV_VERSION) ")");
6a67d144095c31bbafed93cec1619590157335eajvergara/* globals */
6a67d144095c31bbafed93cec1619590157335eajvergara/* forward declarations */
6a67d144095c31bbafed93cec1619590157335eajvergara/* allocate global info, try to map host share */
6a67d144095c31bbafed93cec1619590157335eajvergarastatic int sf_glob_alloc(struct vbsf_mount_info_new *info, struct sf_glob_info **sf_gp)
6a67d144095c31bbafed93cec1619590157335eajvergara LogRelFunc(("could not allocate memory for global info\n"));
6a67d144095c31bbafed93cec1619590157335eajvergara || info->signature[0] != VBSF_MOUNT_SIGNATURE_BYTE_0
6a67d144095c31bbafed93cec1619590157335eajvergara || info->signature[1] != VBSF_MOUNT_SIGNATURE_BYTE_1
6a67d144095c31bbafed93cec1619590157335eajvergara || info->signature[2] != VBSF_MOUNT_SIGNATURE_BYTE_2)
6a67d144095c31bbafed93cec1619590157335eajvergara /* An old version of mount.vboxsf made the syscall. Translate the
6a67d144095c31bbafed93cec1619590157335eajvergara * old parameters to the new structure. */
6a67d144095c31bbafed93cec1619590157335eajvergara struct vbsf_mount_info_old *info_old = (struct vbsf_mount_info_old *)info;
6a67d144095c31bbafed93cec1619590157335eajvergara memcpy(&info->name, &info_old->name, MAX_HOST_NAME);
6a67d144095c31bbafed93cec1619590157335eajvergara memcpy(&info->nls_name, &info_old->nls_name, MAX_NLS_NAME);
6a67d144095c31bbafed93cec1619590157335eajvergara info->length = offsetof(struct vbsf_mount_info_new, dmode);
6a67d144095c31bbafed93cec1619590157335eajvergara str_len = offsetof(SHFLSTRING, String.utf8) + name_len + 1;
6a67d144095c31bbafed93cec1619590157335eajvergara LogRelFunc(("could not allocate memory for host name\n"));
6a67d144095c31bbafed93cec1619590157335eajvergara memcpy(str_name->String.utf8, info->name, name_len + 1);
6a67d144095c31bbafed93cec1619590157335eajvergara if (info->nls_name[0] && strcmp(info->nls_name, "utf8"))
6a67d144095c31bbafed93cec1619590157335eajvergara LogFunc(("failed to load nls %s\n", info->nls_name));
6a67d144095c31bbafed93cec1619590157335eajvergara rc = vboxCallMapFolder(&client_handle, str_name, &sf_g->map);
6a67d144095c31bbafed93cec1619590157335eajvergara if ((unsigned)info->length >= sizeof(struct vbsf_mount_info_new))
6a67d144095c31bbafed93cec1619590157335eajvergara /* new fields */
6a67d144095c31bbafed93cec1619590157335eajvergara/* unmap the share and free global info [sf_g] */
6a67d144095c31bbafed93cec1619590157335eajvergara rc = vboxCallUnmapFolder(&client_handle, &sf_g->map);
6a67d144095c31bbafed93cec1619590157335eajvergara LogFunc(("vboxCallUnmapFolder failed rc=%d\n", rc));
6a67d144095c31bbafed93cec1619590157335eajvergara * This is called (by sf_read_super_[24|26] when vfs mounts the fs and
6a67d144095c31bbafed93cec1619590157335eajvergara * wants to read super_block.
6a67d144095c31bbafed93cec1619590157335eajvergara * calls [sf_glob_alloc] to map the folder and allocate global
6a67d144095c31bbafed93cec1619590157335eajvergara * information structure.
6a67d144095c31bbafed93cec1619590157335eajvergara * initializes [sb], initializes root inode and dentry.
6a67d144095c31bbafed93cec1619590157335eajvergara * should respect [flags]
6a67d144095c31bbafed93cec1619590157335eajvergarastatic int sf_read_super_aux(struct super_block *sb, void *data, int flags)
6a67d144095c31bbafed93cec1619590157335eajvergara LogRelFunc(("could not allocate memory for root inode info\n"));
6a67d144095c31bbafed93cec1619590157335eajvergara sf_i->path = kmalloc(sizeof(SHFLSTRING) + 1, GFP_KERNEL);
6a67d144095c31bbafed93cec1619590157335eajvergara LogRelFunc(("could not allocate memory for root inode path\n"));
6a67d144095c31bbafed93cec1619590157335eajvergara err = sf_stat(__func__, sf_g, sf_i->path, &fsinfo, 0);
6a67d144095c31bbafed93cec1619590157335eajvergara /* Required for seek/sendfile.
6a67d144095c31bbafed93cec1619590157335eajvergara * Must by less than or equal to INT64_MAX despite the fact that the
6a67d144095c31bbafed93cec1619590157335eajvergara * declaration of this variable is unsigned long long. See determination
6a67d144095c31bbafed93cec1619590157335eajvergara * of 'loff_t max' in fs/read_write.c / do_sendfile(). I don't know the
6a67d144095c31bbafed93cec1619590157335eajvergara * correct limit but MAX_LFS_FILESIZE (8TB-1 on 32-bit boxes) takes the
6a67d144095c31bbafed93cec1619590157335eajvergara * page cache into account and is the suggested limit. */
6a67d144095c31bbafed93cec1619590157335eajvergarastatic struct super_block *
6a67d144095c31bbafed93cec1619590157335eajvergarasf_read_super_24(struct super_block *sb, void *data, int flags)
6a67d144095c31bbafed93cec1619590157335eajvergara/* this is called when vfs is about to destroy the [inode]. all
6a67d144095c31bbafed93cec1619590157335eajvergara resources associated with this [inode] must be cleared here */
6a67d144095c31bbafed93cec1619590157335eajvergara/* this is called by vfs when it wants to populate [inode] with data.
6a67d144095c31bbafed93cec1619590157335eajvergara the only thing that is known about inode at this point is its index
6a67d144095c31bbafed93cec1619590157335eajvergara hence we can't do anything here, and let lookup/whatever with the
6a67d144095c31bbafed93cec1619590157335eajvergara job to properly fill then [inode] */
6a67d144095c31bbafed93cec1619590157335eajvergara/* vfs is done with [sb] (umount called) call [sf_glob_free] to unmap
6a67d144095c31bbafed93cec1619590157335eajvergara the folder and free [sf_g] */
6a67d144095c31bbafed93cec1619590157335eajvergarastatic int sf_statfs(struct super_block *sb, STRUCT_STATFS *stat)
6a67d144095c31bbafed93cec1619590157335eajvergarastatic int sf_statfs(struct dentry *dentry, STRUCT_STATFS *stat)
6a67d144095c31bbafed93cec1619590157335eajvergarastatic int sf_remount_fs(struct super_block *sb, int *flags, char *data)
6a67d144095c31bbafed93cec1619590157335eajvergarastatic DECLARE_FSTYPE(vboxsf_fs_type, "vboxsf", sf_read_super_24, 0);
6a67d144095c31bbafed93cec1619590157335eajvergarasf_read_super_26(struct super_block *sb, void *data, int flags)
6a67d144095c31bbafed93cec1619590157335eajvergara printk(KERN_DEBUG "sf_read_super_aux err=%d\n", err);
6a67d144095c31bbafed93cec1619590157335eajvergarastatic struct super_block *sf_get_sb(struct file_system_type *fs_type, int flags,
6a67d144095c31bbafed93cec1619590157335eajvergara return get_sb_nodev(fs_type, flags, data, sf_read_super_26);
6a67d144095c31bbafed93cec1619590157335eajvergarastatic int sf_get_sb(struct file_system_type *fs_type, int flags,
6a67d144095c31bbafed93cec1619590157335eajvergara const char *dev_name, void *data, struct vfsmount *mnt)
6a67d144095c31bbafed93cec1619590157335eajvergara return get_sb_nodev(fs_type, flags, data, sf_read_super_26, mnt);
6a67d144095c31bbafed93cec1619590157335eajvergarastatic int follow_symlinks = 0;
6a67d144095c31bbafed93cec1619590157335eajvergaraMODULE_PARM_DESC(follow_symlinks, "Let host resolve symlinks rather than showing them");
6a67d144095c31bbafed93cec1619590157335eajvergara/* Module initialization/finalization handlers */
6a67d144095c31bbafed93cec1619590157335eajvergara if (sizeof(struct vbsf_mount_info_new) > PAGE_SIZE)
6a67d144095c31bbafed93cec1619590157335eajvergara "Mount information structure is too large %lu\n"
6a67d144095c31bbafed93cec1619590157335eajvergara "Must be less than or equal to %lu\n",
6a67d144095c31bbafed93cec1619590157335eajvergara (unsigned long)sizeof (struct vbsf_mount_info_new),
6a67d144095c31bbafed93cec1619590157335eajvergara (unsigned long)PAGE_SIZE);
6a67d144095c31bbafed93cec1619590157335eajvergara LogRelFunc(("vboxConnect failed, rc=%d\n", rcVBox));
6a67d144095c31bbafed93cec1619590157335eajvergara LogRelFunc(("vboxCallSetUtf8 failed, rc=%d\n", rcVBox));
6a67d144095c31bbafed93cec1619590157335eajvergara "vboxsf: Host unable to show symlinks, rc=%d\n",
6a67d144095c31bbafed93cec1619590157335eajvergara "vboxsf: Successfully loaded version " VBOX_VERSION_STRING
6a67d144095c31bbafed93cec1619590157335eajvergara/* C++ hack */