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linux/arch/um/drivers/ubd_kern.c

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/*
* Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
/* 2001-09-28...2002-04-17
* Partition stuff by James_McMechan@hotmail.com
* old style ubd by setting UBD_SHIFT to 0
* 2002-09-27...2002-10-18 massive tinkering for 2.5
* partitions have changed in 2.5
* 2003-01-29 more tinkering for 2.5.59-1
* This should now address the sysfs problems and has
* the symlink for devfs to allow for booting with
* the common /dev/ubd/discX/... names rather than
* only /dev/ubdN/discN this version also has lots of
* clean ups preparing for ubd-many.
* James McMechan
*/
#define MAJOR_NR UBD_MAJOR
#define UBD_SHIFT 4
#include "linux/config.h"
#include "linux/module.h"
#include "linux/blkdev.h"
#include "linux/hdreg.h"
#include "linux/init.h"
#include "linux/devfs_fs_kernel.h"
#include "linux/cdrom.h"
#include "linux/proc_fs.h"
#include "linux/ctype.h"
#include "linux/capability.h"
#include "linux/mm.h"
#include "linux/vmalloc.h"
#include "linux/blkpg.h"
#include "linux/genhd.h"
#include "linux/spinlock.h"
#include "asm/segment.h"
#include "asm/uaccess.h"
#include "asm/irq.h"
#include "asm/types.h"
#include "asm/tlbflush.h"
#include "user_util.h"
#include "mem_user.h"
#include "kern_util.h"
#include "kern.h"
#include "mconsole_kern.h"
#include "init.h"
#include "irq_user.h"
#include "irq_kern.h"
#include "ubd_user.h"
#include "os.h"
#include "mem.h"
#include "mem_kern.h"
#include "cow.h"
enum ubd_req { UBD_READ, UBD_WRITE };
struct io_thread_req {
enum ubd_req op;
int fds[2];
unsigned long offsets[2];
unsigned long long offset;
unsigned long length;
char *buffer;
int sectorsize;
unsigned long sector_mask;
unsigned long long cow_offset;
unsigned long bitmap_words[2];
int error;
};
extern int open_ubd_file(char *file, struct openflags *openflags,
char **backing_file_out, int *bitmap_offset_out,
unsigned long *bitmap_len_out, int *data_offset_out,
int *create_cow_out);
extern int create_cow_file(char *cow_file, char *backing_file,
struct openflags flags, int sectorsize,
int alignment, int *bitmap_offset_out,
unsigned long *bitmap_len_out,
int *data_offset_out);
extern int read_cow_bitmap(int fd, void *buf, int offset, int len);
extern void do_io(struct io_thread_req *req);
static inline int ubd_test_bit(__u64 bit, unsigned char *data)
{
__u64 n;
int bits, off;
bits = sizeof(data[0]) * 8;
n = bit / bits;
off = bit % bits;
return((data[n] & (1 << off)) != 0);
}
static inline void ubd_set_bit(__u64 bit, unsigned char *data)
{
__u64 n;
int bits, off;
bits = sizeof(data[0]) * 8;
n = bit / bits;
off = bit % bits;
data[n] |= (1 << off);
}
/*End stuff from ubd_user.h*/
#define DRIVER_NAME "uml-blkdev"
static DEFINE_SPINLOCK(ubd_io_lock);
static DEFINE_SPINLOCK(ubd_lock);
static void (*do_ubd)(void);
static int ubd_open(struct inode * inode, struct file * filp);
static int ubd_release(struct inode * inode, struct file * file);
static int ubd_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg);
#define MAX_DEV (8)
static struct block_device_operations ubd_blops = {
.owner = THIS_MODULE,
.open = ubd_open,
.release = ubd_release,
.ioctl = ubd_ioctl,
};
/* Protected by the queue_lock */
static request_queue_t *ubd_queue;
/* Protected by ubd_lock */
static int fake_major = MAJOR_NR;
static struct gendisk *ubd_gendisk[MAX_DEV];
static struct gendisk *fake_gendisk[MAX_DEV];
#ifdef CONFIG_BLK_DEV_UBD_SYNC
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
.cl = 1 })
#else
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
.cl = 1 })
#endif
/* Not protected - changed only in ubd_setup_common and then only to
* to enable O_SYNC.
*/
static struct openflags global_openflags = OPEN_FLAGS;
struct cow {
/* This is the backing file, actually */
char *file;
int fd;
unsigned long *bitmap;
unsigned long bitmap_len;
int bitmap_offset;
int data_offset;
};
struct ubd {
char *file;
int count;
int fd;
__u64 size;
struct openflags boot_openflags;
struct openflags openflags;
int no_cow;
struct cow cow;
struct platform_device pdev;
};
#define DEFAULT_COW { \
.file = NULL, \
.fd = -1, \
.bitmap = NULL, \
.bitmap_offset = 0, \
.data_offset = 0, \
}
#define DEFAULT_UBD { \
.file = NULL, \
.count = 0, \
.fd = -1, \
.size = -1, \
.boot_openflags = OPEN_FLAGS, \
.openflags = OPEN_FLAGS, \
.no_cow = 0, \
.cow = DEFAULT_COW, \
}
struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD };
static int ubd0_init(void)
{
struct ubd *dev = &ubd_dev[0];
if(dev->file == NULL)
dev->file = "root_fs";
return(0);
}
__initcall(ubd0_init);
/* Only changed by fake_ide_setup which is a setup */
static int fake_ide = 0;
static struct proc_dir_entry *proc_ide_root = NULL;
static struct proc_dir_entry *proc_ide = NULL;
static void make_proc_ide(void)
{
proc_ide_root = proc_mkdir("ide", NULL);
proc_ide = proc_mkdir("ide0", proc_ide_root);
}
static int proc_ide_read_media(char *page, char **start, off_t off, int count,
int *eof, void *data)
{
int len;
strcpy(page, "disk\n");
len = strlen("disk\n");
len -= off;
if (len < count){
*eof = 1;
if (len <= 0) return 0;
}
else len = count;
*start = page + off;
return len;
}
static void make_ide_entries(char *dev_name)
{
struct proc_dir_entry *dir, *ent;
char name[64];
if(proc_ide_root == NULL) make_proc_ide();
dir = proc_mkdir(dev_name, proc_ide);
if(!dir) return;
ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir);
if(!ent) return;
ent->nlink = 1;
ent->data = NULL;
ent->read_proc = proc_ide_read_media;
ent->write_proc = NULL;
sprintf(name,"ide0/%s", dev_name);
proc_symlink(dev_name, proc_ide_root, name);
}
static int fake_ide_setup(char *str)
{
fake_ide = 1;
return(1);
}
__setup("fake_ide", fake_ide_setup);
__uml_help(fake_ide_setup,
"fake_ide\n"
" Create ide0 entries that map onto ubd devices.\n\n"
);
static int parse_unit(char **ptr)
{
char *str = *ptr, *end;
int n = -1;
if(isdigit(*str)) {
n = simple_strtoul(str, &end, 0);
if(end == str)
return(-1);
*ptr = end;
}
else if (('a' <= *str) && (*str <= 'h')) {
n = *str - 'a';
str++;
*ptr = str;
}
return(n);
}
static int ubd_setup_common(char *str, int *index_out)
{
struct ubd *dev;
struct openflags flags = global_openflags;
char *backing_file;
int n, err, i;
if(index_out) *index_out = -1;
n = *str;
if(n == '='){
char *end;
int major;
str++;
if(!strcmp(str, "sync")){
global_openflags = of_sync(global_openflags);
return(0);
}
major = simple_strtoul(str, &end, 0);
if((*end != '\0') || (end == str)){
printk(KERN_ERR
"ubd_setup : didn't parse major number\n");
return(1);
}
err = 1;
spin_lock(&ubd_lock);
if(fake_major != MAJOR_NR){
printk(KERN_ERR "Can't assign a fake major twice\n");
goto out1;
}
fake_major = major;
printk(KERN_INFO "Setting extra ubd major number to %d\n",
major);
err = 0;
out1:
spin_unlock(&ubd_lock);
return(err);
}
n = parse_unit(&str);
if(n < 0){
printk(KERN_ERR "ubd_setup : couldn't parse unit number "
"'%s'\n", str);
return(1);
}
if(n >= MAX_DEV){
printk(KERN_ERR "ubd_setup : index %d out of range "
"(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1);
return(1);
}
err = 1;
spin_lock(&ubd_lock);
dev = &ubd_dev[n];
if(dev->file != NULL){
printk(KERN_ERR "ubd_setup : device already configured\n");
goto out;
}
if (index_out)
*index_out = n;
for (i = 0; i < 4; i++) {
switch (*str) {
case 'r':
flags.w = 0;
break;
case 's':
flags.s = 1;
break;
case 'd':
dev->no_cow = 1;
break;
case '=':
str++;
goto break_loop;
default:
printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r,s or d)\n");
goto out;
}
str++;
}
if (*str == '=')
printk(KERN_ERR "ubd_setup : Too many flags specified\n");
else
printk(KERN_ERR "ubd_setup : Expected '='\n");
goto out;
break_loop:
err = 0;
backing_file = strchr(str, ',');
if (!backing_file) {
backing_file = strchr(str, ':');
}
if(backing_file){
if(dev->no_cow)
printk(KERN_ERR "Can't specify both 'd' and a "
"cow file\n");
else {
*backing_file = '\0';
backing_file++;
}
}
dev->file = str;
dev->cow.file = backing_file;
dev->boot_openflags = flags;
out:
spin_unlock(&ubd_lock);
return(err);
}
static int ubd_setup(char *str)
{
ubd_setup_common(str, NULL);
return(1);
}
__setup("ubd", ubd_setup);
__uml_help(ubd_setup,
"ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
" This is used to associate a device with a file in the underlying\n"
" filesystem. When specifying two filenames, the first one is the\n"
" COW name and the second is the backing file name. As separator you can\n"
" use either a ':' or a ',': the first one allows writing things like;\n"
" ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
" while with a ',' the shell would not expand the 2nd '~'.\n"
" When using only one filename, UML will detect whether to thread it like\n"
" a COW file or a backing file. To override this detection, add the 'd'\n"
" flag:\n"
" ubd0d=BackingFile\n"
" Usually, there is a filesystem in the file, but \n"
" that's not required. Swap devices containing swap files can be\n"
" specified like this. Also, a file which doesn't contain a\n"
" filesystem can have its contents read in the virtual \n"
" machine by running 'dd' on the device. <n> must be in the range\n"
" 0 to 7. Appending an 'r' to the number will cause that device\n"
" to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
" an 's' will cause data to be written to disk on the host immediately.\n\n"
);
static int udb_setup(char *str)
{
printk("udb%s specified on command line is almost certainly a ubd -> "
"udb TYPO\n", str);
return(1);
}
__setup("udb", udb_setup);
__uml_help(udb_setup,
"udb\n"
" This option is here solely to catch ubd -> udb typos, which can be\n"
" to impossible to catch visually unless you specifically look for\n"
" them. The only result of any option starting with 'udb' is an error\n"
" in the boot output.\n\n"
);
static int fakehd_set = 0;
static int fakehd(char *str)
{
printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n");
fakehd_set = 1;
return 1;
}
__setup("fakehd", fakehd);
__uml_help(fakehd,
"fakehd\n"
" Change the ubd device name to \"hd\".\n\n"
);
static void do_ubd_request(request_queue_t * q);
/* Only changed by ubd_init, which is an initcall. */
int thread_fd = -1;
/* Changed by ubd_handler, which is serialized because interrupts only
* happen on CPU 0.
*/
int intr_count = 0;
/* call ubd_finish if you need to serialize */
static void __ubd_finish(struct request *req, int error)
{
int nsect;
if(error){
end_request(req, 0);
return;
}
nsect = req->current_nr_sectors;
req->sector += nsect;
req->buffer += nsect << 9;
req->errors = 0;
req->nr_sectors -= nsect;
req->current_nr_sectors = 0;
end_request(req, 1);
}
static inline void ubd_finish(struct request *req, int error)
{
spin_lock(&ubd_io_lock);
__ubd_finish(req, error);
spin_unlock(&ubd_io_lock);
}
/* Called without ubd_io_lock held */
static void ubd_handler(void)
{
struct io_thread_req req;
struct request *rq = elv_next_request(ubd_queue);
int n;
do_ubd = NULL;
intr_count++;
n = os_read_file(thread_fd, &req, sizeof(req));
if(n != sizeof(req)){
printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, "
"err = %d\n", os_getpid(), -n);
spin_lock(&ubd_io_lock);
end_request(rq, 0);
spin_unlock(&ubd_io_lock);
return;
}
ubd_finish(rq, req.error);
reactivate_fd(thread_fd, UBD_IRQ);
do_ubd_request(ubd_queue);
}
static irqreturn_t ubd_intr(int irq, void *dev, struct pt_regs *unused)
{
ubd_handler();
return(IRQ_HANDLED);
}
/* Only changed by ubd_init, which is an initcall. */
static int io_pid = -1;
void kill_io_thread(void)
{
if(io_pid != -1)
os_kill_process(io_pid, 1);
}
__uml_exitcall(kill_io_thread);
static int ubd_file_size(struct ubd *dev, __u64 *size_out)
{
char *file;
file = dev->cow.file ? dev->cow.file : dev->file;
return(os_file_size(file, size_out));
}
static void ubd_close(struct ubd *dev)
{
os_close_file(dev->fd);
if(dev->cow.file == NULL)
return;
os_close_file(dev->cow.fd);
vfree(dev->cow.bitmap);
dev->cow.bitmap = NULL;
}
static int ubd_open_dev(struct ubd *dev)
{
struct openflags flags;
char **back_ptr;
int err, create_cow, *create_ptr;
dev->openflags = dev->boot_openflags;
create_cow = 0;
create_ptr = (dev->cow.file != NULL) ? &create_cow : NULL;
back_ptr = dev->no_cow ? NULL : &dev->cow.file;
dev->fd = open_ubd_file(dev->file, &dev->openflags, back_ptr,
&dev->cow.bitmap_offset, &dev->cow.bitmap_len,
&dev->cow.data_offset, create_ptr);
if((dev->fd == -ENOENT) && create_cow){
dev->fd = create_cow_file(dev->file, dev->cow.file,
dev->openflags, 1 << 9, PAGE_SIZE,
&dev->cow.bitmap_offset,
&dev->cow.bitmap_len,
&dev->cow.data_offset);
if(dev->fd >= 0){
printk(KERN_INFO "Creating \"%s\" as COW file for "
"\"%s\"\n", dev->file, dev->cow.file);
}
}
if(dev->fd < 0){
printk("Failed to open '%s', errno = %d\n", dev->file,
-dev->fd);
return(dev->fd);
}
if(dev->cow.file != NULL){
err = -ENOMEM;
dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len);
if(dev->cow.bitmap == NULL){
printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
goto error;
}
flush_tlb_kernel_vm();
err = read_cow_bitmap(dev->fd, dev->cow.bitmap,
dev->cow.bitmap_offset,
dev->cow.bitmap_len);
if(err < 0)
goto error;
flags = dev->openflags;
flags.w = 0;
err = open_ubd_file(dev->cow.file, &flags, NULL, NULL, NULL,
NULL, NULL);
if(err < 0) goto error;
dev->cow.fd = err;
}
return(0);
error:
os_close_file(dev->fd);
return(err);
}
static int ubd_new_disk(int major, u64 size, int unit,
struct gendisk **disk_out)
{
struct gendisk *disk;
char from[sizeof("ubd/nnnnn\0")], to[sizeof("discnnnnn/disc\0")];
int err;
disk = alloc_disk(1 << UBD_SHIFT);
if(disk == NULL)
return(-ENOMEM);
disk->major = major;
disk->first_minor = unit << UBD_SHIFT;
disk->fops = &ubd_blops;
set_capacity(disk, size / 512);
if(major == MAJOR_NR){
sprintf(disk->disk_name, "ubd%c", 'a' + unit);
sprintf(disk->devfs_name, "ubd/disc%d", unit);
sprintf(from, "ubd/%d", unit);
sprintf(to, "disc%d/disc", unit);
err = devfs_mk_symlink(from, to);
if(err)
printk("ubd_new_disk failed to make link from %s to "
"%s, error = %d\n", from, to, err);
}
else {
sprintf(disk->disk_name, "ubd_fake%d", unit);
sprintf(disk->devfs_name, "ubd_fake/disc%d", unit);
}
/* sysfs register (not for ide fake devices) */
if (major == MAJOR_NR) {
ubd_dev[unit].pdev.id = unit;
ubd_dev[unit].pdev.name = DRIVER_NAME;
platform_device_register(&ubd_dev[unit].pdev);
disk->driverfs_dev = &ubd_dev[unit].pdev.dev;
}
disk->private_data = &ubd_dev[unit];
disk->queue = ubd_queue;
add_disk(disk);
*disk_out = disk;
return 0;
}
#define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9))
static int ubd_add(int n)
{
struct ubd *dev = &ubd_dev[n];
int err;
if(dev->file == NULL)
return(-ENODEV);
if (ubd_open_dev(dev))
return(-ENODEV);
err = ubd_file_size(dev, &dev->size);
if(err < 0)
return(err);
dev->size = ROUND_BLOCK(dev->size);
err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]);
if(err)
return(err);
if(fake_major != MAJOR_NR)
ubd_new_disk(fake_major, dev->size, n,
&fake_gendisk[n]);
/* perhaps this should also be under the "if (fake_major)" above */
/* using the fake_disk->disk_name and also the fakehd_set name */
if (fake_ide)
make_ide_entries(ubd_gendisk[n]->disk_name);
ubd_close(dev);
return 0;
}
static int ubd_config(char *str)
{
int n, err;
str = uml_strdup(str);
if(str == NULL){
printk(KERN_ERR "ubd_config failed to strdup string\n");
return(1);
}
err = ubd_setup_common(str, &n);
if(err){
kfree(str);
return(-1);
}
if(n == -1) return(0);
spin_lock(&ubd_lock);
err = ubd_add(n);
if(err)
ubd_dev[n].file = NULL;
spin_unlock(&ubd_lock);
return(err);
}
static int ubd_get_config(char *name, char *str, int size, char **error_out)
{
struct ubd *dev;
int n, len = 0;
n = parse_unit(&name);
if((n >= MAX_DEV) || (n < 0)){
*error_out = "ubd_get_config : device number out of range";
return(-1);
}
dev = &ubd_dev[n];
spin_lock(&ubd_lock);
if(dev->file == NULL){
CONFIG_CHUNK(str, size, len, "", 1);
goto out;
}
CONFIG_CHUNK(str, size, len, dev->file, 0);
if(dev->cow.file != NULL){
CONFIG_CHUNK(str, size, len, ",", 0);
CONFIG_CHUNK(str, size, len, dev->cow.file, 1);
}
else CONFIG_CHUNK(str, size, len, "", 1);
out:
spin_unlock(&ubd_lock);
return(len);
}
static int ubd_id(char **str, int *start_out, int *end_out)
{
int n;
n = parse_unit(str);
*start_out = 0;
*end_out = MAX_DEV - 1;
return n;
}
static int ubd_remove(int n)
{
struct ubd *dev;
int err = -ENODEV;
spin_lock(&ubd_lock);
if(ubd_gendisk[n] == NULL)
goto out;
dev = &ubd_dev[n];
if(dev->file == NULL)
goto out;
/* you cannot remove a open disk */
err = -EBUSY;
if(dev->count > 0)
goto out;
del_gendisk(ubd_gendisk[n]);
put_disk(ubd_gendisk[n]);
ubd_gendisk[n] = NULL;
if(fake_gendisk[n] != NULL){
del_gendisk(fake_gendisk[n]);
put_disk(fake_gendisk[n]);
fake_gendisk[n] = NULL;
}
platform_device_unregister(&dev->pdev);
*dev = ((struct ubd) DEFAULT_UBD);
err = 0;
out:
spin_unlock(&ubd_lock);
return err;
}
static struct mc_device ubd_mc = {
.name = "ubd",
.config = ubd_config,
.get_config = ubd_get_config,
.id = ubd_id,
.remove = ubd_remove,
};
static int ubd_mc_init(void)
{
mconsole_register_dev(&ubd_mc);
return 0;
}
__initcall(ubd_mc_init);
static struct device_driver ubd_driver = {
.name = DRIVER_NAME,
.bus = &platform_bus_type,
};
int ubd_init(void)
{
int i;
devfs_mk_dir("ubd");
if (register_blkdev(MAJOR_NR, "ubd"))
return -1;
ubd_queue = blk_init_queue(do_ubd_request, &ubd_io_lock);
if (!ubd_queue) {
unregister_blkdev(MAJOR_NR, "ubd");
return -1;
}
if (fake_major != MAJOR_NR) {
char name[sizeof("ubd_nnn\0")];
snprintf(name, sizeof(name), "ubd_%d", fake_major);
devfs_mk_dir(name);
if (register_blkdev(fake_major, "ubd"))
return -1;
}
driver_register(&ubd_driver);
for (i = 0; i < MAX_DEV; i++)
ubd_add(i);
return 0;
}
late_initcall(ubd_init);
int ubd_driver_init(void){
unsigned long stack;
int err;
/* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
if(global_openflags.s){
printk(KERN_INFO "ubd: Synchronous mode\n");
/* Letting ubd=sync be like using ubd#s= instead of ubd#= is
* enough. So use anyway the io thread. */
}
stack = alloc_stack(0, 0);
io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
&thread_fd);
if(io_pid < 0){
printk(KERN_ERR
"ubd : Failed to start I/O thread (errno = %d) - "
"falling back to synchronous I/O\n", -io_pid);
io_pid = -1;
return(0);
}
err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
SA_INTERRUPT, "ubd", ubd_dev);
if(err != 0)
printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
return(err);
}
device_initcall(ubd_driver_init);
static int ubd_open(struct inode *inode, struct file *filp)
{
struct gendisk *disk = inode->i_bdev->bd_disk;
struct ubd *dev = disk->private_data;
int err = 0;
if(dev->count == 0){
err = ubd_open_dev(dev);
if(err){
printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
disk->disk_name, dev->file, -err);
goto out;
}
}
dev->count++;
set_disk_ro(disk, !dev->openflags.w);
/* This should no more be needed. And it didn't work anyway to exclude
* read-write remounting of filesystems.*/
/*if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){
if(--dev->count == 0) ubd_close(dev);
err = -EROFS;
}*/
out:
return(err);
}
static int ubd_release(struct inode * inode, struct file * file)
{
struct gendisk *disk = inode->i_bdev->bd_disk;
struct ubd *dev = disk->private_data;
if(--dev->count == 0)
ubd_close(dev);
return(0);
}
static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
__u64 *cow_offset, unsigned long *bitmap,
__u64 bitmap_offset, unsigned long *bitmap_words,
__u64 bitmap_len)
{
__u64 sector = io_offset >> 9;
int i, update_bitmap = 0;
for(i = 0; i < length >> 9; i++){
if(cow_mask != NULL)
ubd_set_bit(i, (unsigned char *) cow_mask);
if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
continue;
update_bitmap = 1;
ubd_set_bit(sector + i, (unsigned char *) bitmap);
}
if(!update_bitmap)
return;
*cow_offset = sector / (sizeof(unsigned long) * 8);
/* This takes care of the case where we're exactly at the end of the
* device, and *cow_offset + 1 is off the end. So, just back it up
* by one word. Thanks to Lynn Kerby for the fix and James McMechan
* for the original diagnosis.
*/
if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) /
sizeof(unsigned long) - 1))
(*cow_offset)--;
bitmap_words[0] = bitmap[*cow_offset];
bitmap_words[1] = bitmap[*cow_offset + 1];
*cow_offset *= sizeof(unsigned long);
*cow_offset += bitmap_offset;
}
static void cowify_req(struct io_thread_req *req, unsigned long *bitmap,
__u64 bitmap_offset, __u64 bitmap_len)
{
__u64 sector = req->offset >> 9;
int i;
if(req->length > (sizeof(req->sector_mask) * 8) << 9)
panic("Operation too long");
if(req->op == UBD_READ) {
for(i = 0; i < req->length >> 9; i++){
if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
ubd_set_bit(i, (unsigned char *)
&req->sector_mask);
}
}
else cowify_bitmap(req->offset, req->length, &req->sector_mask,
&req->cow_offset, bitmap, bitmap_offset,
req->bitmap_words, bitmap_len);
}
/* Called with ubd_io_lock held */
static int prepare_request(struct request *req, struct io_thread_req *io_req)
{
struct gendisk *disk = req->rq_disk;
struct ubd *dev = disk->private_data;
__u64 offset;
int len;
if(req->rq_status == RQ_INACTIVE) return(1);
/* This should be impossible now */
if((rq_data_dir(req) == WRITE) && !dev->openflags.w){
printk("Write attempted on readonly ubd device %s\n",
disk->disk_name);
end_request(req, 0);
return(1);
}
offset = ((__u64) req->sector) << 9;
len = req->current_nr_sectors << 9;
io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd;
io_req->fds[1] = dev->fd;
io_req->cow_offset = -1;
io_req->offset = offset;
io_req->length = len;
io_req->error = 0;
io_req->sector_mask = 0;
io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE;
io_req->offsets[0] = 0;
io_req->offsets[1] = dev->cow.data_offset;
io_req->buffer = req->buffer;
io_req->sectorsize = 1 << 9;
if(dev->cow.file != NULL)
cowify_req(io_req, dev->cow.bitmap, dev->cow.bitmap_offset,
dev->cow.bitmap_len);
return(0);
}
/* Called with ubd_io_lock held */
static void do_ubd_request(request_queue_t *q)
{
struct io_thread_req io_req;
struct request *req;
int err, n;
if(thread_fd == -1){
while((req = elv_next_request(q)) != NULL){
err = prepare_request(req, &io_req);
if(!err){
do_io(&io_req);
__ubd_finish(req, io_req.error);
}
}
}
else {
if(do_ubd || (req = elv_next_request(q)) == NULL)
return;
err = prepare_request(req, &io_req);
if(!err){
do_ubd = ubd_handler;
n = os_write_file(thread_fd, (char *) &io_req,
sizeof(io_req));
if(n != sizeof(io_req))
printk("write to io thread failed, "
"errno = %d\n", -n);
}
}
}
static int ubd_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg)
{
struct hd_geometry __user *loc = (struct hd_geometry __user *) arg;
struct ubd *dev = inode->i_bdev->bd_disk->private_data;
struct hd_driveid ubd_id = {
.cyls = 0,
.heads = 128,
.sectors = 32,
};
switch (cmd) {
struct hd_geometry g;
struct cdrom_volctrl volume;
case HDIO_GETGEO:
if(!loc) return(-EINVAL);
g.heads = 128;
g.sectors = 32;
g.cylinders = dev->size / (128 * 32 * 512);
g.start = get_start_sect(inode->i_bdev);
return(copy_to_user(loc, &g, sizeof(g)) ? -EFAULT : 0);
case HDIO_GET_IDENTITY:
ubd_id.cyls = dev->size / (128 * 32 * 512);
if(copy_to_user((char __user *) arg, (char *) &ubd_id,
sizeof(ubd_id)))
return(-EFAULT);
return(0);
case CDROMVOLREAD:
if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
return(-EFAULT);
volume.channel0 = 255;
volume.channel1 = 255;
volume.channel2 = 255;
volume.channel3 = 255;
if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
return(-EFAULT);
return(0);
}
return(-EINVAL);
}
static int same_backing_files(char *from_cmdline, char *from_cow, char *cow)
{
struct uml_stat buf1, buf2;
int err;
if(from_cmdline == NULL) return(1);
if(!strcmp(from_cmdline, from_cow)) return(1);
err = os_stat_file(from_cmdline, &buf1);
if(err < 0){
printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err);
return(1);
}
err = os_stat_file(from_cow, &buf2);
if(err < 0){
printk("Couldn't stat '%s', err = %d\n", from_cow, -err);
return(1);
}
if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
return(1);
printk("Backing file mismatch - \"%s\" requested,\n"
"\"%s\" specified in COW header of \"%s\"\n",
from_cmdline, from_cow, cow);
return(0);
}
static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
{
unsigned long modtime;
long long actual;
int err;
err = os_file_modtime(file, &modtime);
if(err < 0){
printk("Failed to get modification time of backing file "
"\"%s\", err = %d\n", file, -err);
return(err);
}
err = os_file_size(file, &actual);
if(err < 0){
printk("Failed to get size of backing file \"%s\", "
"err = %d\n", file, -err);
return(err);
}
if(actual != size){
/*__u64 can be a long on AMD64 and with %lu GCC complains; so
* the typecast.*/
printk("Size mismatch (%llu vs %llu) of COW header vs backing "
"file\n", (unsigned long long) size, actual);
return(-EINVAL);
}
if(modtime != mtime){
printk("mtime mismatch (%ld vs %ld) of COW header vs backing "
"file\n", mtime, modtime);
return(-EINVAL);
}
return(0);
}
int read_cow_bitmap(int fd, void *buf, int offset, int len)
{
int err;
err = os_seek_file(fd, offset);
if(err < 0)
return(err);
err = os_read_file(fd, buf, len);
if(err < 0)
return(err);
return(0);
}
int open_ubd_file(char *file, struct openflags *openflags,
char **backing_file_out, int *bitmap_offset_out,
unsigned long *bitmap_len_out, int *data_offset_out,
int *create_cow_out)
{
time_t mtime;
unsigned long long size;
__u32 version, align;
char *backing_file;
int fd, err, sectorsize, same, mode = 0644;
fd = os_open_file(file, *openflags, mode);
if(fd < 0){
if((fd == -ENOENT) && (create_cow_out != NULL))
*create_cow_out = 1;
if(!openflags->w ||
((fd != -EROFS) && (fd != -EACCES))) return(fd);
openflags->w = 0;
fd = os_open_file(file, *openflags, mode);
if(fd < 0)
return(fd);
}
err = os_lock_file(fd, openflags->w);
if(err < 0){
printk("Failed to lock '%s', err = %d\n", file, -err);
goto out_close;
}
if(backing_file_out == NULL) return(fd);
err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
&size, &sectorsize, &align, bitmap_offset_out);
if(err && (*backing_file_out != NULL)){
printk("Failed to read COW header from COW file \"%s\", "
"errno = %d\n", file, -err);
goto out_close;
}
if(err) return(fd);
if(backing_file_out == NULL) return(fd);
same = same_backing_files(*backing_file_out, backing_file, file);
if(!same && !backing_file_mismatch(*backing_file_out, size, mtime)){
printk("Switching backing file to '%s'\n", *backing_file_out);
err = write_cow_header(file, fd, *backing_file_out,
sectorsize, align, &size);
if(err){
printk("Switch failed, errno = %d\n", -err);
return(err);
}
}
else {
*backing_file_out = backing_file;
err = backing_file_mismatch(*backing_file_out, size, mtime);
if(err) goto out_close;
}
cow_sizes(version, size, sectorsize, align, *bitmap_offset_out,
bitmap_len_out, data_offset_out);
return(fd);
out_close:
os_close_file(fd);
return(err);
}
int create_cow_file(char *cow_file, char *backing_file, struct openflags flags,
int sectorsize, int alignment, int *bitmap_offset_out,
unsigned long *bitmap_len_out, int *data_offset_out)
{
int err, fd;
flags.c = 1;
fd = open_ubd_file(cow_file, &flags, NULL, NULL, NULL, NULL, NULL);
if(fd < 0){
err = fd;
printk("Open of COW file '%s' failed, errno = %d\n", cow_file,
-err);
goto out;
}
err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment,
bitmap_offset_out, bitmap_len_out,
data_offset_out);
if(!err)
return(fd);
os_close_file(fd);
out:
return(err);
}
static int update_bitmap(struct io_thread_req *req)
{
int n;
if(req->cow_offset == -1)
return(0);
n = os_seek_file(req->fds[1], req->cow_offset);
if(n < 0){
printk("do_io - bitmap lseek failed : err = %d\n", -n);
return(1);
}
n = os_write_file(req->fds[1], &req->bitmap_words,
sizeof(req->bitmap_words));
if(n != sizeof(req->bitmap_words)){
printk("do_io - bitmap update failed, err = %d fd = %d\n", -n,
req->fds[1]);
return(1);
}
return(0);
}
void do_io(struct io_thread_req *req)
{
char *buf;
unsigned long len;
int n, nsectors, start, end, bit;
int err;
__u64 off;
nsectors = req->length / req->sectorsize;
start = 0;
do {
bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask);
end = start;
while((end < nsectors) &&
(ubd_test_bit(end, (unsigned char *)
&req->sector_mask) == bit))
end++;
off = req->offset + req->offsets[bit] +
start * req->sectorsize;
len = (end - start) * req->sectorsize;
buf = &req->buffer[start * req->sectorsize];
err = os_seek_file(req->fds[bit], off);
if(err < 0){
printk("do_io - lseek failed : err = %d\n", -err);
req->error = 1;
return;
}
if(req->op == UBD_READ){
n = 0;
do {
buf = &buf[n];
len -= n;
n = os_read_file(req->fds[bit], buf, len);
if (n < 0) {
printk("do_io - read failed, err = %d "
"fd = %d\n", -n, req->fds[bit]);
req->error = 1;
return;
}
} while((n < len) && (n != 0));
if (n < len) memset(&buf[n], 0, len - n);
} else {
n = os_write_file(req->fds[bit], buf, len);
if(n != len){
printk("do_io - write failed err = %d "
"fd = %d\n", -n, req->fds[bit]);
req->error = 1;
return;
}
}
start = end;
} while(start < nsectors);
req->error = update_bitmap(req);
}
/* Changed in start_io_thread, which is serialized by being called only
* from ubd_init, which is an initcall.
*/
int kernel_fd = -1;
/* Only changed by the io thread */
int io_count = 0;
int io_thread(void *arg)
{
struct io_thread_req req;
int n;
ignore_sigwinch_sig();
while(1){
n = os_read_file(kernel_fd, &req, sizeof(req));
if(n != sizeof(req)){
if(n < 0)
printk("io_thread - read failed, fd = %d, "
"err = %d\n", kernel_fd, -n);
else {
printk("io_thread - short read, fd = %d, "
"length = %d\n", kernel_fd, n);
}
continue;
}
io_count++;
do_io(&req);
n = os_write_file(kernel_fd, &req, sizeof(req));
if(n != sizeof(req))
printk("io_thread - write failed, fd = %d, err = %d\n",
kernel_fd, -n);
}
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
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