linux/arch/um/drivers/ubd_kern.c

1439 lines
33 KiB
C
Raw Normal View History

/*
* 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 UBD_SHIFT 4
#include "linux/kernel.h"
#include "linux/module.h"
#include "linux/blkdev.h"
#include "linux/ata.h"
#include "linux/hdreg.h"
#include "linux/init.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 "linux/platform_device.h"
#include "linux/scatterlist.h"
#include "asm/segment.h"
#include "asm/uaccess.h"
#include "asm/irq.h"
#include "asm/types.h"
#include "asm/tlbflush.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 {
struct request *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;
};
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_MUTEX(ubd_lock);
static int ubd_open(struct block_device *bdev, fmode_t mode);
static int ubd_release(struct gendisk *disk, fmode_t mode);
static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg);
static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
#define MAX_DEV (16)
static struct block_device_operations ubd_blops = {
.owner = THIS_MODULE,
.open = ubd_open,
.release = ubd_release,
.ioctl = ubd_ioctl,
.getgeo = ubd_getgeo,
};
/* Protected by ubd_lock */
static int fake_major = UBD_MAJOR;
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
static struct openflags global_openflags = OPEN_FLAGS;
struct cow {
/* backing file name */
char *file;
/* backing file fd */
int fd;
unsigned long *bitmap;
unsigned long bitmap_len;
int bitmap_offset;
int data_offset;
};
#define MAX_SG 64
struct ubd {
struct list_head restart;
/* name (and fd, below) of the file opened for writing, either the
* backing or the cow file. */
char *file;
int count;
int fd;
__u64 size;
struct openflags boot_openflags;
struct openflags openflags;
unsigned shared:1;
unsigned no_cow:1;
struct cow cow;
struct platform_device pdev;
struct request_queue *queue;
spinlock_t lock;
struct scatterlist sg[MAX_SG];
struct request *request;
int start_sg, end_sg;
};
#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, \
.shared = 0, \
.cow = DEFAULT_COW, \
.lock = SPIN_LOCK_UNLOCKED, \
.request = NULL, \
.start_sg = 0, \
.end_sg = 0, \
}
/* Protected by ubd_lock */
static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
/* 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(const 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->data = NULL;
ent->read_proc = proc_ide_read_media;
ent->write_proc = NULL;
snprintf(name, sizeof(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 <= 'z')) {
n = *str - 'a';
str++;
*ptr = str;
}
return n;
}
/* If *index_out == -1 at exit, the passed option was a general one;
* otherwise, the str pointer is used (and owned) inside ubd_devs array, so it
* should not be freed on exit.
*/
static int ubd_setup_common(char *str, int *index_out, char **error_out)
{
struct ubd *ubd_dev;
struct openflags flags = global_openflags;
char *backing_file;
int n, err = 0, 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);
goto out1;
}
err = -EINVAL;
major = simple_strtoul(str, &end, 0);
if((*end != '\0') || (end == str)){
*error_out = "Didn't parse major number";
goto out1;
}
mutex_lock(&ubd_lock);
if (fake_major != UBD_MAJOR) {
*error_out = "Can't assign a fake major twice";
goto out1;
}
fake_major = major;
printk(KERN_INFO "Setting extra ubd major number to %d\n",
major);
err = 0;
out1:
mutex_unlock(&ubd_lock);
return err;
}
n = parse_unit(&str);
if(n < 0){
*error_out = "Couldn't parse device number";
return -EINVAL;
}
if(n >= MAX_DEV){
*error_out = "Device number out of range";
return 1;
}
err = -EBUSY;
mutex_lock(&ubd_lock);
ubd_dev = &ubd_devs[n];
if(ubd_dev->file != NULL){
*error_out = "Device is already configured";
goto out;
}
if (index_out)
*index_out = n;
err = -EINVAL;
for (i = 0; i < sizeof("rscd="); i++) {
switch (*str) {
case 'r':
flags.w = 0;
break;
case 's':
flags.s = 1;
break;
case 'd':
ubd_dev->no_cow = 1;
break;
case 'c':
ubd_dev->shared = 1;
break;
case '=':
str++;
goto break_loop;
default:
*error_out = "Expected '=' or flag letter "
"(r, s, c, or d)";
goto out;
}
str++;
}
if (*str == '=')
*error_out = "Too many flags specified";
else
*error_out = "Missing '='";
goto out;
break_loop:
backing_file = strchr(str, ',');
if (backing_file == NULL)
backing_file = strchr(str, ':');
if(backing_file != NULL){
if(ubd_dev->no_cow){
*error_out = "Can't specify both 'd' and a cow file";
goto out;
}
else {
*backing_file = '\0';
backing_file++;
}
}
err = 0;
ubd_dev->file = str;
ubd_dev->cow.file = backing_file;
ubd_dev->boot_openflags = flags;
out:
mutex_unlock(&ubd_lock);
return err;
}
static int ubd_setup(char *str)
{
char *error;
int err;
err = ubd_setup_common(str, NULL, &error);
if(err)
printk(KERN_ERR "Failed to initialize device with \"%s\" : "
"%s\n", str, error);
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 treat 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"
" 'c' will cause the device to be treated as being shared between multiple\n"
" UMLs and file locking will be turned off - this is appropriate for a\n"
" cluster filesystem and inappropriate at almost all other times.\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 void do_ubd_request(struct request_queue * q);
/* Only changed by ubd_init, which is an initcall. */
static int thread_fd = -1;
static LIST_HEAD(restart);
/* XXX - move this inside ubd_intr. */
/* Called without dev->lock held, and only in interrupt context. */
static void ubd_handler(void)
{
struct io_thread_req *req;
struct ubd *ubd;
struct list_head *list, *next_ele;
unsigned long flags;
int n;
while(1){
n = os_read_file(thread_fd, &req,
sizeof(struct io_thread_req *));
if(n != sizeof(req)){
if(n == -EAGAIN)
break;
printk(KERN_ERR "spurious interrupt in ubd_handler, "
"err = %d\n", -n);
return;
}
blk_end_request(req->req, 0, req->length);
kfree(req);
}
reactivate_fd(thread_fd, UBD_IRQ);
list_for_each_safe(list, next_ele, &restart){
ubd = container_of(list, struct ubd, restart);
list_del_init(&ubd->restart);
spin_lock_irqsave(&ubd->lock, flags);
do_ubd_request(ubd->queue);
spin_unlock_irqrestore(&ubd->lock, flags);
}
}
static irqreturn_t ubd_intr(int irq, void *dev)
{
ubd_handler();
return IRQ_HANDLED;
}
/* Only changed by ubd_init, which is an initcall. */
static int io_pid = -1;
static void kill_io_thread(void)
{
if(io_pid != -1)
os_kill_process(io_pid, 1);
}
__uml_exitcall(kill_io_thread);
static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out)
{
char *file;
file = ubd_dev->cow.file ? ubd_dev->cow.file : ubd_dev->file;
return os_file_size(file, size_out);
}
static 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;
}
static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
{
unsigned long modtime;
unsigned long long actual;
int err;
err = os_file_modtime(file, &modtime);
if (err < 0) {
printk(KERN_ERR "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(KERN_ERR "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(KERN_ERR "Size mismatch (%llu vs %llu) of COW header "
"vs backing file\n", (unsigned long long) size, actual);
return -EINVAL;
}
if (modtime != mtime) {
printk(KERN_ERR "mtime mismatch (%ld vs %ld) of COW header vs "
"backing file\n", mtime, modtime);
return -EINVAL;
}
return 0;
}
static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
{
struct uml_stat buf1, buf2;
int err;
if (from_cmdline == NULL)
return 0;
if (!strcmp(from_cmdline, from_cow))
return 0;
err = os_stat_file(from_cmdline, &buf1);
if (err < 0) {
printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline,
-err);
return 0;
}
err = os_stat_file(from_cow, &buf2);
if (err < 0) {
printk(KERN_ERR "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 0;
printk(KERN_ERR "Backing file mismatch - \"%s\" requested, "
"\"%s\" specified in COW header of \"%s\"\n",
from_cmdline, from_cow, cow);
return 1;
}
static int open_ubd_file(char *file, struct openflags *openflags, int shared,
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, asked_switch, 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;
}
if (shared)
printk(KERN_INFO "Not locking \"%s\" on the host\n", file);
else {
err = os_lock_file(fd, openflags->w);
if (err < 0) {
printk(KERN_ERR "Failed to lock '%s', err = %d\n",
file, -err);
goto out_close;
}
}
/* Successful return case! */
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(KERN_ERR "Failed to read COW header from COW file "
"\"%s\", errno = %d\n", file, -err);
goto out_close;
}
if (err)
return fd;
asked_switch = path_requires_switch(*backing_file_out, backing_file,
file);
/* Allow switching only if no mismatch. */
if (asked_switch && !backing_file_mismatch(*backing_file_out, size,
mtime)) {
printk(KERN_ERR "Switching backing file to '%s'\n",
*backing_file_out);
err = write_cow_header(file, fd, *backing_file_out,
sectorsize, align, &size);
if (err) {
printk(KERN_ERR "Switch failed, errno = %d\n", -err);
goto out_close;
}
} 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;
}
static 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, 0, NULL, NULL, NULL, NULL, NULL);
if (fd < 0) {
err = fd;
printk(KERN_ERR "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 void ubd_close_dev(struct ubd *ubd_dev)
{
os_close_file(ubd_dev->fd);
if(ubd_dev->cow.file == NULL)
return;
os_close_file(ubd_dev->cow.fd);
vfree(ubd_dev->cow.bitmap);
ubd_dev->cow.bitmap = NULL;
}
static int ubd_open_dev(struct ubd *ubd_dev)
{
struct openflags flags;
char **back_ptr;
int err, create_cow, *create_ptr;
int fd;
ubd_dev->openflags = ubd_dev->boot_openflags;
create_cow = 0;
create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL;
back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file;
fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared,
back_ptr, &ubd_dev->cow.bitmap_offset,
&ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset,
create_ptr);
if((fd == -ENOENT) && create_cow){
fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file,
ubd_dev->openflags, 1 << 9, PAGE_SIZE,
&ubd_dev->cow.bitmap_offset,
&ubd_dev->cow.bitmap_len,
&ubd_dev->cow.data_offset);
if(fd >= 0){
printk(KERN_INFO "Creating \"%s\" as COW file for "
"\"%s\"\n", ubd_dev->file, ubd_dev->cow.file);
}
}
if(fd < 0){
printk("Failed to open '%s', errno = %d\n", ubd_dev->file,
-fd);
return fd;
}
ubd_dev->fd = fd;
if(ubd_dev->cow.file != NULL){
blk_queue_max_sectors(ubd_dev->queue, 8 * sizeof(long));
err = -ENOMEM;
ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len);
if(ubd_dev->cow.bitmap == NULL){
printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
goto error;
}
flush_tlb_kernel_vm();
err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
ubd_dev->cow.bitmap_offset,
ubd_dev->cow.bitmap_len);
if(err < 0)
goto error;
flags = ubd_dev->openflags;
flags.w = 0;
err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL,
NULL, NULL, NULL, NULL);
if(err < 0) goto error;
ubd_dev->cow.fd = err;
}
return 0;
error:
os_close_file(ubd_dev->fd);
return err;
}
static void ubd_device_release(struct device *dev)
{
struct ubd *ubd_dev = dev->driver_data;
blk_cleanup_queue(ubd_dev->queue);
*ubd_dev = ((struct ubd) DEFAULT_UBD);
}
static int ubd_disk_register(int major, u64 size, int unit,
struct gendisk **disk_out)
{
struct gendisk *disk;
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 == UBD_MAJOR)
sprintf(disk->disk_name, "ubd%c", 'a' + unit);
else
sprintf(disk->disk_name, "ubd_fake%d", unit);
/* sysfs register (not for ide fake devices) */
if (major == UBD_MAJOR) {
ubd_devs[unit].pdev.id = unit;
ubd_devs[unit].pdev.name = DRIVER_NAME;
ubd_devs[unit].pdev.dev.release = ubd_device_release;
ubd_devs[unit].pdev.dev.driver_data = &ubd_devs[unit];
platform_device_register(&ubd_devs[unit].pdev);
disk->driverfs_dev = &ubd_devs[unit].pdev.dev;
}
disk->private_data = &ubd_devs[unit];
disk->queue = ubd_devs[unit].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, char **error_out)
{
struct ubd *ubd_dev = &ubd_devs[n];
int err = 0;
if(ubd_dev->file == NULL)
goto out;
err = ubd_file_size(ubd_dev, &ubd_dev->size);
if(err < 0){
*error_out = "Couldn't determine size of device's file";
goto out;
}
ubd_dev->size = ROUND_BLOCK(ubd_dev->size);
INIT_LIST_HEAD(&ubd_dev->restart);
sg_init_table(ubd_dev->sg, MAX_SG);
err = -ENOMEM;
ubd_dev->queue = blk_init_queue(do_ubd_request, &ubd_dev->lock);
if (ubd_dev->queue == NULL) {
*error_out = "Failed to initialize device queue";
goto out;
}
ubd_dev->queue->queuedata = ubd_dev;
blk_queue_max_hw_segments(ubd_dev->queue, MAX_SG);
err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
if(err){
*error_out = "Failed to register device";
goto out_cleanup;
}
if (fake_major != UBD_MAJOR)
ubd_disk_register(fake_major, ubd_dev->size, n,
&fake_gendisk[n]);
/*
* Perhaps this should also be under the "if (fake_major)" above
* using the fake_disk->disk_name
*/
if (fake_ide)
make_ide_entries(ubd_gendisk[n]->disk_name);
err = 0;
out:
return err;
out_cleanup:
blk_cleanup_queue(ubd_dev->queue);
goto out;
}
static int ubd_config(char *str, char **error_out)
{
int n, ret;
/* This string is possibly broken up and stored, so it's only
* freed if ubd_setup_common fails, or if only general options
* were set.
*/
str = kstrdup(str, GFP_KERNEL);
if (str == NULL) {
*error_out = "Failed to allocate memory";
return -ENOMEM;
}
ret = ubd_setup_common(str, &n, error_out);
if (ret)
goto err_free;
if (n == -1) {
ret = 0;
goto err_free;
}
mutex_lock(&ubd_lock);
ret = ubd_add(n, error_out);
if (ret)
ubd_devs[n].file = NULL;
mutex_unlock(&ubd_lock);
out:
return ret;
err_free:
kfree(str);
goto out;
}
static int ubd_get_config(char *name, char *str, int size, char **error_out)
{
struct ubd *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;
}
ubd_dev = &ubd_devs[n];
mutex_lock(&ubd_lock);
if(ubd_dev->file == NULL){
CONFIG_CHUNK(str, size, len, "", 1);
goto out;
}
CONFIG_CHUNK(str, size, len, ubd_dev->file, 0);
if(ubd_dev->cow.file != NULL){
CONFIG_CHUNK(str, size, len, ",", 0);
CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1);
}
else CONFIG_CHUNK(str, size, len, "", 1);
out:
mutex_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, char **error_out)
{
struct gendisk *disk = ubd_gendisk[n];
struct ubd *ubd_dev;
int err = -ENODEV;
mutex_lock(&ubd_lock);
ubd_dev = &ubd_devs[n];
if(ubd_dev->file == NULL)
goto out;
/* you cannot remove a open disk */
err = -EBUSY;
if(ubd_dev->count > 0)
goto out;
ubd_gendisk[n] = NULL;
if(disk != NULL){
del_gendisk(disk);
put_disk(disk);
}
if(fake_gendisk[n] != NULL){
del_gendisk(fake_gendisk[n]);
put_disk(fake_gendisk[n]);
fake_gendisk[n] = NULL;
}
err = 0;
platform_device_unregister(&ubd_dev->pdev);
out:
mutex_unlock(&ubd_lock);
return err;
}
/* All these are called by mconsole in process context and without
* ubd-specific locks. The structure itself is const except for .list.
*/
static struct mc_device ubd_mc = {
.list = LIST_HEAD_INIT(ubd_mc.list),
.name = "ubd",
.config = ubd_config,
.get_config = ubd_get_config,
.id = ubd_id,
.remove = ubd_remove,
};
static int __init ubd_mc_init(void)
{
mconsole_register_dev(&ubd_mc);
return 0;
}
__initcall(ubd_mc_init);
static int __init ubd0_init(void)
{
struct ubd *ubd_dev = &ubd_devs[0];
mutex_lock(&ubd_lock);
if(ubd_dev->file == NULL)
ubd_dev->file = "root_fs";
mutex_unlock(&ubd_lock);
return 0;
}
__initcall(ubd0_init);
/* Used in ubd_init, which is an initcall */
static struct platform_driver ubd_driver = {
.driver = {
.name = DRIVER_NAME,
},
};
static int __init ubd_init(void)
{
char *error;
int i, err;
if (register_blkdev(UBD_MAJOR, "ubd"))
return -1;
if (fake_major != UBD_MAJOR) {
char name[sizeof("ubd_nnn\0")];
snprintf(name, sizeof(name), "ubd_%d", fake_major);
if (register_blkdev(fake_major, "ubd"))
return -1;
}
platform_driver_register(&ubd_driver);
mutex_lock(&ubd_lock);
for (i = 0; i < MAX_DEV; i++){
err = ubd_add(i, &error);
if(err)
printk(KERN_ERR "Failed to initialize ubd device %d :"
"%s\n", i, error);
}
mutex_unlock(&ubd_lock);
return 0;
}
late_initcall(ubd_init);
static int __init 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,
IRQF_DISABLED, "ubd", ubd_devs);
if(err != 0)
printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
return 0;
}
device_initcall(ubd_driver_init);
static int ubd_open(struct block_device *bdev, fmode_t mode)
{
struct gendisk *disk = bdev->bd_disk;
struct ubd *ubd_dev = disk->private_data;
int err = 0;
if(ubd_dev->count == 0){
err = ubd_open_dev(ubd_dev);
if(err){
printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
disk->disk_name, ubd_dev->file, -err);
goto out;
}
}
ubd_dev->count++;
set_disk_ro(disk, !ubd_dev->openflags.w);
/* This should no more be needed. And it didn't work anyway to exclude
* read-write remounting of filesystems.*/
/*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){
if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
err = -EROFS;
}*/
out:
return err;
}
static int ubd_release(struct gendisk *disk, fmode_t mode)
{
struct ubd *ubd_dev = disk->private_data;
if(--ubd_dev->count == 0)
ubd_close_dev(ubd_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 == (DIV_ROUND_UP(bitmap_len,
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 dev->lock held */
static void prepare_request(struct request *req, struct io_thread_req *io_req,
unsigned long long offset, int page_offset,
int len, struct page *page)
{
struct gendisk *disk = req->rq_disk;
struct ubd *ubd_dev = disk->private_data;
io_req->req = req;
io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd :
ubd_dev->fd;
io_req->fds[1] = ubd_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] = ubd_dev->cow.data_offset;
io_req->buffer = page_address(page) + page_offset;
io_req->sectorsize = 1 << 9;
if(ubd_dev->cow.file != NULL)
cowify_req(io_req, ubd_dev->cow.bitmap,
ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len);
}
/* Called with dev->lock held */
static void do_ubd_request(struct request_queue *q)
{
struct io_thread_req *io_req;
struct request *req;
sector_t sector;
int n;
while(1){
struct ubd *dev = q->queuedata;
if(dev->end_sg == 0){
block: implement and enforce request peek/start/fetch Till now block layer allowed two separate modes of request execution. A request is always acquired from the request queue via elv_next_request(). After that, drivers are free to either dequeue it or process it without dequeueing. Dequeue allows elv_next_request() to return the next request so that multiple requests can be in flight. Executing requests without dequeueing has its merits mostly in allowing drivers for simpler devices which can't do sg to deal with segments only without considering request boundary. However, the benefit this brings is dubious and declining while the cost of the API ambiguity is increasing. Segment based drivers are usually for very old or limited devices and as converting to dequeueing model isn't difficult, it doesn't justify the API overhead it puts on block layer and its more modern users. Previous patches converted all block low level drivers to dequeueing model. This patch completes the API transition by... * renaming elv_next_request() to blk_peek_request() * renaming blkdev_dequeue_request() to blk_start_request() * adding blk_fetch_request() which is combination of peek and start * disallowing completion of queued (not started) requests * applying new API to all LLDs Renamings are for consistency and to break out of tree code so that it's apparent that out of tree drivers need updating. [ Impact: block request issue API cleanup, no functional change ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Mike Miller <mike.miller@hp.com> Cc: unsik Kim <donari75@gmail.com> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Cc: David S. Miller <davem@davemloft.net> Cc: Laurent Vivier <Laurent@lvivier.info> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: Pierre Ossman <drzeus@drzeus.cx> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Markus Lidel <Markus.Lidel@shadowconnect.com> Cc: Stefan Weinhuber <wein@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-08 02:54:16 +00:00
struct request *req = blk_fetch_request(q);
if(req == NULL)
return;
dev->request = req;
dev->start_sg = 0;
dev->end_sg = blk_rq_map_sg(q, req, dev->sg);
}
req = dev->request;
block: convert to pos and nr_sectors accessors With recent cleanups, there is no place where low level driver directly manipulates request fields. This means that the 'hard' request fields always equal the !hard fields. Convert all rq->sectors, nr_sectors and current_nr_sectors references to accessors. While at it, drop superflous blk_rq_pos() < 0 test in swim.c. [ Impact: use pos and nr_sectors accessors ] Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Tested-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Grant Likely <grant.likely@secretlab.ca> Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Mike Miller <mike.miller@hp.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Dario Ballabio <ballabio_dario@emc.com> Cc: David S. Miller <davem@davemloft.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: unsik Kim <donari75@gmail.com> Cc: Laurent Vivier <Laurent@lvivier.info> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-07 13:24:39 +00:00
sector = blk_rq_pos(req);
while(dev->start_sg < dev->end_sg){
struct scatterlist *sg = &dev->sg[dev->start_sg];
io_req = kmalloc(sizeof(struct io_thread_req),
GFP_ATOMIC);
if(io_req == NULL){
if(list_empty(&dev->restart))
list_add(&dev->restart, &restart);
return;
}
prepare_request(req, io_req,
(unsigned long long)sector << 9,
sg->offset, sg->length, sg_page(sg));
sector += sg->length >> 9;
n = os_write_file(thread_fd, &io_req,
sizeof(struct io_thread_req *));
if(n != sizeof(struct io_thread_req *)){
if(n != -EAGAIN)
printk("write to io thread failed, "
"errno = %d\n", -n);
else if(list_empty(&dev->restart))
list_add(&dev->restart, &restart);
kfree(io_req);
return;
}
dev->start_sg++;
}
dev->end_sg = 0;
dev->request = NULL;
}
}
static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct ubd *ubd_dev = bdev->bd_disk->private_data;
geo->heads = 128;
geo->sectors = 32;
geo->cylinders = ubd_dev->size / (128 * 32 * 512);
return 0;
}
static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct ubd *ubd_dev = bdev->bd_disk->private_data;
u16 ubd_id[ATA_ID_WORDS];
switch (cmd) {
struct cdrom_volctrl volume;
case HDIO_GET_IDENTITY:
memset(&ubd_id, 0, ATA_ID_WORDS * 2);
ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512);
ubd_id[ATA_ID_HEADS] = 128;
ubd_id[ATA_ID_SECTORS] = 32;
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 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;
}
static 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. XXX: currently unused. */
static 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(struct io_thread_req *));
if(n != sizeof(struct io_thread_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(struct io_thread_req *));
if(n != sizeof(struct io_thread_req *))
printk("io_thread - write failed, fd = %d, err = %d\n",
kernel_fd, -n);
}
return 0;
}