* 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
#include "mconsole_kern.h"
#include "init.h"
#include "irq_user.h"
+#include "irq_kern.h"
#include "ubd_user.h"
#include "2_5compat.h"
#include "os.h"
+#include "mem.h"
+#include "mem_kern.h"
static spinlock_t ubd_io_lock = SPIN_LOCK_UNLOCKED;
static spinlock_t ubd_lock = SPIN_LOCK_UNLOCKED;
#define MAX_DEV (8)
+/* Changed in early boot */
+static int ubd_do_mmap = 0;
+#define UBD_MMAP_BLOCK_SIZE PAGE_SIZE
+
static struct block_device_operations ubd_blops = {
.owner = THIS_MODULE,
.open = ubd_open,
static request_queue_t *ubd_queue;
/* Protected by ubd_lock */
-static int fake_major = 0;
+static int fake_major = MAJOR_NR;
static struct gendisk *ubd_gendisk[MAX_DEV];
static struct gendisk *fake_gendisk[MAX_DEV];
struct ubd {
char *file;
- int is_dir;
int count;
int fd;
__u64 size;
struct openflags boot_openflags;
struct openflags openflags;
+ int no_cow;
struct cow cow;
+
+ int map_writes;
+ int map_reads;
+ int nomap_writes;
+ int nomap_reads;
+ int write_maps;
};
#define DEFAULT_COW { \
#define DEFAULT_UBD { \
.file = NULL, \
- .is_dir = 0, \
.count = 0, \
.fd = -1, \
.size = -1, \
.boot_openflags = OPEN_FLAGS, \
.openflags = OPEN_FLAGS, \
+ .no_cow = 0, \
.cow = DEFAULT_COW, \
+ .map_writes = 0, \
+ .map_reads = 0, \
+ .nomap_writes = 0, \
+ .nomap_reads = 0, \
+ .write_maps = 0, \
}
struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD };
static int ubd0_init(void)
{
- if(ubd_dev[0].file == NULL)
- ubd_dev[0].file = "root_fs";
+ struct ubd *dev = &ubd_dev[0];
+
+ if(dev->file == NULL)
+ dev->file = "root_fs";
return(0);
}
" 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;
if(index_out) *index_out = -1;
- n = *str++;
+ n = *str;
if(n == '='){
- static int fake_major_allowed = 1;
char *end;
int major;
+ str++;
+ if(!strcmp(str, "mmap")){
+ CHOOSE_MODE(printk("mmap not supported by the ubd "
+ "driver in tt mode\n"),
+ ubd_do_mmap = 1);
+ return(0);
+ }
+
if(!strcmp(str, "sync")){
global_openflags.s = 1;
return(0);
return(1);
}
- if(!fake_major_allowed){
- printk(KERN_ERR "Can't assign a fake major twice\n");
- return(1);
- }
-
err = 1;
spin_lock(&ubd_lock);
- if(!fake_major_allowed){
+ if(fake_major != MAJOR_NR){
printk(KERN_ERR "Can't assign a fake major twice\n");
goto out1;
}
fake_major = major;
- fake_major_allowed = 0;
printk(KERN_INFO "Setting extra ubd major number to %d\n",
major);
return(err);
}
- if(n < '0'){
- printk(KERN_ERR "ubd_setup : index out of range\n"); }
-
- if((n >= '0') && (n <= '9')) n -= '0';
- else if((n >= 'a') && (n <= 'z')) n -= 'a';
- else {
- printk(KERN_ERR "ubd_setup : device syntax invalid\n");
+ 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 out of range "
- "(%d devices)\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);
- if(ubd_dev[n].file != NULL){
+ dev = &ubd_dev[n];
+ if(dev->file != NULL){
printk(KERN_ERR "ubd_setup : device already configured\n");
goto out2;
}
flags.s = 1;
str++;
}
+ if (*str == 'd'){
+ dev->no_cow = 1;
+ str++;
+ }
+
if(*str++ != '='){
printk(KERN_ERR "ubd_setup : Expected '='\n");
goto out2;
err = 0;
backing_file = strchr(str, ',');
if(backing_file){
- *backing_file = '\0';
- backing_file++;
- }
- ubd_dev[n].file = str;
- if(ubd_is_dir(ubd_dev[n].file))
- ubd_dev[n].is_dir = 1;
- ubd_dev[n].cow.file = backing_file;
- ubd_dev[n].boot_openflags = flags;
+ 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;
out2:
spin_unlock(&ubd_lock);
return(err);
static int fakehd_set = 0;
static int fakehd(char *str)
{
- printk(KERN_INFO
- "fakehd : Changing ubd name to \"hd\".\n");
+ printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n");
fakehd_set = 1;
return 1;
}
*/
int intr_count = 0;
-static void ubd_finish(struct request *req, int error)
+/* call ubd_finish if you need to serialize */
+static void __ubd_finish(struct request *req, int error)
{
int nsect;
if(error){
- spin_lock(&ubd_io_lock);
end_request(req, 0);
- spin_unlock(&ubd_io_lock);
return;
}
nsect = req->current_nr_sectors;
req->errors = 0;
req->nr_sectors -= nsect;
req->current_nr_sectors = 0;
- spin_lock(&ubd_io_lock);
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;
+ int n, err;
do_ubd = NULL;
intr_count++;
n = read_ubd_fs(thread_fd, &req, sizeof(req));
if(n != sizeof(req)){
printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, "
- "errno = %d\n", os_getpid(), -n);
+ "err = %d\n", os_getpid(), -n);
spin_lock(&ubd_io_lock);
end_request(rq, 0);
spin_unlock(&ubd_io_lock);
return;
}
- if((req.offset != ((__u64) (rq->sector)) << 9) ||
- (req.length != (rq->current_nr_sectors) << 9))
+ if((req.op != UBD_MMAP) &&
+ ((req.offset != ((__u64) (rq->sector)) << 9) ||
+ (req.length != (rq->current_nr_sectors) << 9)))
panic("I/O op mismatch");
+ if(req.map_fd != -1){
+ err = physmem_subst_mapping(req.buffer, req.map_fd,
+ req.map_offset, 1);
+ if(err)
+ printk("ubd_handler - physmem_subst_mapping failed, "
+ "err = %d\n", -err);
+ }
+
ubd_finish(rq, req.error);
reactivate_fd(thread_fd, UBD_IRQ);
do_ubd_request(ubd_queue);
}
-static void ubd_intr(int irq, void *dev, struct pt_regs *unused)
+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 void ubd_close(struct ubd *dev)
{
+ if(ubd_do_mmap)
+ physmem_forget_descriptor(dev->fd);
os_close_file(dev->fd);
if(dev->cow.file == NULL)
return;
+ if(ubd_do_mmap)
+ physmem_forget_descriptor(dev->cow.fd);
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;
- int err, n, create_cow, *create_ptr;
+ 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;
- dev->fd = open_ubd_file(dev->file, &dev->openflags, &dev->cow.file,
+ 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){
- n = dev - ubd_dev;
dev->fd = create_cow_file(dev->file, dev->cow.file,
- dev->openflags, 1 << 9,
+ dev->openflags, 1 << 9, PAGE_SIZE,
&dev->cow.bitmap_offset,
&dev->cow.bitmap_len,
&dev->cow.data_offset);
if(dev->cow.file != NULL){
err = -ENOMEM;
dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len);
- if(dev->cow.bitmap == NULL) goto error;
+ 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) goto error;
+ if(err < 0)
+ goto error;
flags = dev->openflags;
flags.w = 0;
{
struct gendisk *disk;
+ char from[sizeof("ubd/nnnnn\0")], to[sizeof("discnnnnn/disc\0")];
+ int err;
disk = alloc_disk(1 << UBD_SHIFT);
- if (!disk)
- return -ENOMEM;
+ if(disk == NULL)
+ return(-ENOMEM);
disk->major = major;
disk->first_minor = unit << UBD_SHIFT;
disk->fops = &ubd_blops;
set_capacity(disk, size / 512);
- sprintf(disk->disk_name, "ubd");
- sprintf(disk->devfs_name, "ubd/disc%d", unit);
+ 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);
+ }
disk->private_data = &ubd_dev[unit];
disk->queue = ubd_queue;
struct ubd *dev = &ubd_dev[n];
int err;
- if(dev->is_dir)
- return(-EISDIR);
-
- if (!dev->file)
+ if(dev->file == NULL)
return(-ENODEV);
if (ubd_open_dev(dev))
return(-ENODEV);
err = ubd_file_size(dev, &dev->size);
- if(err)
+ if(err < 0)
return(err);
err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]);
if(err)
return(err);
- if(fake_major)
+ if(fake_major != MAJOR_NR)
ubd_new_disk(fake_major, dev->size, n,
&fake_gendisk[n]);
return(err);
}
-static int ubd_get_config(char *dev, char *str, int size, char **error_out)
+static int ubd_get_config(char *name, char *str, int size, char **error_out)
{
- struct ubd *ubd;
+ struct ubd *dev;
char *end;
- int major, n = 0;
+ int n, len = 0;
- major = simple_strtoul(dev, &end, 0);
- if((*end != '\0') || (end == dev)){
- *error_out = "ubd_get_config : didn't parse major number";
+ n = simple_strtoul(name, &end, 0);
+ if((*end != '\0') || (end == name)){
+ *error_out = "ubd_get_config : didn't parse device number";
return(-1);
}
- if((major >= MAX_DEV) || (major < 0)){
- *error_out = "ubd_get_config : major number out of range";
+ if((n >= MAX_DEV) || (n < 0)){
+ *error_out = "ubd_get_config : device number out of range";
return(-1);
}
- ubd = &ubd_dev[major];
+ dev = &ubd_dev[n];
spin_lock(&ubd_lock);
- if(ubd->file == NULL){
- CONFIG_CHUNK(str, size, n, "", 1);
+ if(dev->file == NULL){
+ CONFIG_CHUNK(str, size, len, "", 1);
goto out;
}
- CONFIG_CHUNK(str, size, n, ubd->file, 0);
+ CONFIG_CHUNK(str, size, len, dev->file, 0);
- if(ubd->cow.file != NULL){
- CONFIG_CHUNK(str, size, n, ",", 0);
- CONFIG_CHUNK(str, size, n, ubd->cow.file, 1);
+ 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, n, "", 1);
+ else CONFIG_CHUNK(str, size, len, "", 1);
out:
spin_unlock(&ubd_lock);
- return(n);
+ return(len);
}
static int ubd_remove(char *str)
struct ubd *dev;
int n, err = -ENODEV;
- if(!isdigit(*str))
- return(err); /* it should be a number 0-7/a-h */
+ n = parse_unit(&str);
- n = *str - '0';
- if(n >= MAX_DEV)
+ if((n < 0) || (n >= MAX_DEV))
return(err);
dev = &ubd_dev[n];
return -1;
}
- elevator_init(ubd_queue, &elevator_noop);
-
- if (fake_major != 0) {
+ if (fake_major != MAJOR_NR) {
char name[sizeof("ubd_nnn\0")];
snprintf(name, sizeof(name), "ubd_%d", fake_major);
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");
- return(0);
+ 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 *),
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);
+ if(err != 0)
+ printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
return(err);
}
{
struct gendisk *disk = inode->i_bdev->bd_disk;
struct ubd *dev = disk->private_data;
- int err = -EISDIR;
-
- if(dev->is_dir == 1)
- goto out;
+ int err = 0;
- err = 0;
if(dev->count == 0){
- dev->openflags = dev->boot_openflags;
-
err = ubd_open_dev(dev);
if(err){
printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
return(0);
}
-void cowify_req(struct io_thread_req *req, struct ubd *dev)
+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)
{
- int i, update_bitmap, sector = req->offset >> 9;
+ __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 *)
- dev->cow.bitmap)){
+ if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
ubd_set_bit(i, (unsigned char *)
&req->sector_mask);
- }
}
- }
- else {
- update_bitmap = 0;
- for(i = 0; i < req->length >> 9; i++){
- ubd_set_bit(i, (unsigned char *)
- &req->sector_mask);
- if(!ubd_test_bit(sector + i, (unsigned char *)
- dev->cow.bitmap))
- update_bitmap = 1;
- ubd_set_bit(sector + i, (unsigned char *)
- dev->cow.bitmap);
- }
- if(update_bitmap){
- req->cow_offset = sector / (sizeof(unsigned long) * 8);
- req->bitmap_words[0] =
- dev->cow.bitmap[req->cow_offset];
- req->bitmap_words[1] =
- dev->cow.bitmap[req->cow_offset + 1];
- req->cow_offset *= sizeof(unsigned long);
- req->cow_offset += dev->cow.bitmap_offset;
+ }
+ else cowify_bitmap(req->offset, req->length, &req->sector_mask,
+ &req->cow_offset, bitmap, bitmap_offset,
+ req->bitmap_words, bitmap_len);
+}
+
+static int mmap_fd(struct request *req, struct ubd *dev, __u64 offset)
+{
+ __u64 sector;
+ unsigned char *bitmap;
+ int bit, i;
+
+ /* mmap must have been requested on the command line */
+ if(!ubd_do_mmap)
+ return(-1);
+
+ /* The buffer must be page aligned */
+ if(((unsigned long) req->buffer % UBD_MMAP_BLOCK_SIZE) != 0)
+ return(-1);
+
+ /* The request must be a page long */
+ if((req->current_nr_sectors << 9) != PAGE_SIZE)
+ return(-1);
+
+ if(dev->cow.file == NULL)
+ return(dev->fd);
+
+ sector = offset >> 9;
+ bitmap = (unsigned char *) dev->cow.bitmap;
+ bit = ubd_test_bit(sector, bitmap);
+
+ for(i = 1; i < req->current_nr_sectors; i++){
+ if(ubd_test_bit(sector + i, bitmap) != bit)
+ return(-1);
+ }
+
+ if(bit || (rq_data_dir(req) == WRITE))
+ offset += dev->cow.data_offset;
+
+ /* The data on disk must be page aligned */
+ if((offset % UBD_MMAP_BLOCK_SIZE) != 0)
+ return(-1);
+
+ return(bit ? dev->fd : dev->cow.fd);
+}
+
+static int prepare_mmap_request(struct ubd *dev, int fd, __u64 offset,
+ struct request *req,
+ struct io_thread_req *io_req)
+{
+ int err;
+
+ if(rq_data_dir(req) == WRITE){
+ /* Writes are almost no-ops since the new data is already in the
+ * host page cache
+ */
+ dev->map_writes++;
+ if(dev->cow.file != NULL)
+ cowify_bitmap(io_req->offset, io_req->length,
+ &io_req->sector_mask, &io_req->cow_offset,
+ dev->cow.bitmap, dev->cow.bitmap_offset,
+ io_req->bitmap_words,
+ dev->cow.bitmap_len);
+ }
+ else {
+ int w;
+
+ if((dev->cow.file != NULL) && (fd == dev->cow.fd))
+ w = 0;
+ else w = dev->openflags.w;
+
+ if((dev->cow.file != NULL) && (fd == dev->fd))
+ offset += dev->cow.data_offset;
+
+ err = physmem_subst_mapping(req->buffer, fd, offset, w);
+ if(err){
+ printk("physmem_subst_mapping failed, err = %d\n",
+ -err);
+ return(1);
}
+ dev->map_reads++;
}
+ io_req->op = UBD_MMAP;
+ io_req->buffer = req->buffer;
+ return(0);
}
+/* 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 block;
- int nsect;
+ __u64 offset;
+ int len, fd;
if(req->rq_status == RQ_INACTIVE) return(1);
- if(dev->is_dir){
- strcpy(req->buffer, "HOSTFS:");
- strcat(req->buffer, dev->file);
- spin_lock(&ubd_io_lock);
- end_request(req, 1);
- spin_unlock(&ubd_io_lock);
- return(1);
- }
-
if((rq_data_dir(req) == WRITE) && !dev->openflags.w){
printk("Write attempted on readonly ubd device %s\n",
disk->disk_name);
- spin_lock(&ubd_io_lock);
end_request(req, 0);
- spin_unlock(&ubd_io_lock);
return(1);
}
- block = req->sector;
- nsect = req->current_nr_sectors;
+ offset = ((__u64) req->sector) << 9;
+ len = req->current_nr_sectors << 9;
- io_req->op = rq_data_dir(req) == READ ? UBD_READ : UBD_WRITE;
io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd;
io_req->fds[1] = dev->fd;
+ io_req->map_fd = -1;
+ io_req->cow_offset = -1;
+ io_req->offset = offset;
+ io_req->length = len;
+ io_req->error = 0;
+ io_req->sector_mask = 0;
+
+ fd = mmap_fd(req, dev, io_req->offset);
+ if(fd > 0){
+ /* If mmapping is otherwise OK, but the first access to the
+ * page is a write, then it's not mapped in yet. So we have
+ * to write the data to disk first, then we can map the disk
+ * page in and continue normally from there.
+ */
+ if((rq_data_dir(req) == WRITE) && !is_remapped(req->buffer)){
+ io_req->map_fd = dev->fd;
+ io_req->map_offset = io_req->offset +
+ dev->cow.data_offset;
+ dev->write_maps++;
+ }
+ else return(prepare_mmap_request(dev, fd, io_req->offset, req,
+ io_req));
+ }
+
+ if(rq_data_dir(req) == READ)
+ dev->nomap_reads++;
+ else dev->nomap_writes++;
+
+ 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->offset = ((__u64) block) << 9;
- io_req->length = nsect << 9;
io_req->buffer = req->buffer;
io_req->sectorsize = 1 << 9;
- io_req->sector_mask = 0;
- io_req->cow_offset = -1;
- io_req->error = 0;
- if(dev->cow.file != NULL) cowify_req(io_req, dev);
+ 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;
int err, n;
if(thread_fd == -1){
- while(!list_empty(&q->queue_head)){
- req = elv_next_request(q);
+ 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);
+ __ubd_finish(req, io_req.error);
}
}
}
else {
- if(do_ubd || list_empty(&q->queue_head)) return;
- req = elv_next_request(q);
+ if(do_ubd || (req = elv_next_request(q)) == NULL)
+ return;
err = prepare_request(req, &io_req);
if(!err){
do_ubd = ubd_handler;
{
struct hd_geometry *loc = (struct hd_geometry *) arg;
struct ubd *dev = inode->i_bdev->bd_disk->private_data;
- int err;
struct hd_driveid ubd_id = {
.cyls = 0,
.heads = 128,
g.heads = 128;
g.sectors = 32;
g.cylinders = dev->size / (128 * 32 * 512);
- g.start = 2;
+ g.start = get_start_sect(inode->i_bdev);
return(copy_to_user(loc, &g, sizeof(g)) ? -EFAULT : 0);
- case HDIO_SET_UNMASKINTR:
- if(!capable(CAP_SYS_ADMIN)) return(-EACCES);
- if((arg > 1) || (inode->i_bdev->bd_contains != inode->i_bdev))
- return(-EINVAL);
- return(0);
-
- case HDIO_GET_UNMASKINTR:
- if(!arg) return(-EINVAL);
- err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
- if(err)
- return(err);
- return(0);
-
- case HDIO_GET_MULTCOUNT:
- if(!arg) return(-EINVAL);
- err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
- if(err)
- return(err);
- return(0);
-
- case HDIO_SET_MULTCOUNT:
- if(!capable(CAP_SYS_ADMIN)) return(-EACCES);
- if(inode->i_bdev->bd_contains != inode->i_bdev)
- return(-EINVAL);
- return(0);
-
case HDIO_GET_IDENTITY:
ubd_id.cyls = dev->size / (128 * 32 * 512);
if(copy_to_user((char *) arg, (char *) &ubd_id,
return(-EINVAL);
}
+static int ubd_check_remapped(int fd, unsigned long address, int is_write,
+ __u64 offset)
+{
+ __u64 bitmap_offset;
+ unsigned long new_bitmap[2];
+ int i, err, n;
+
+ /* If it's not a write access, we can't do anything about it */
+ if(!is_write)
+ return(0);
+
+ /* We have a write */
+ for(i = 0; i < sizeof(ubd_dev) / sizeof(ubd_dev[0]); i++){
+ struct ubd *dev = &ubd_dev[i];
+
+ if((dev->fd != fd) && (dev->cow.fd != fd))
+ continue;
+
+ /* It's a write to a ubd device */
+
+ if(!dev->openflags.w){
+ /* It's a write access on a read-only device - probably
+ * shouldn't happen. If the kernel is trying to change
+ * something with no intention of writing it back out,
+ * then this message will clue us in that this needs
+ * fixing
+ */
+ printk("Write access to mapped page from readonly ubd "
+ "device %d\n", i);
+ return(0);
+ }
+
+ /* It's a write to a writeable ubd device - it must be COWed
+ * because, otherwise, the page would have been mapped in
+ * writeable
+ */
+
+ if(!dev->cow.file)
+ panic("Write fault on writeable non-COW ubd device %d",
+ i);
+
+ /* It should also be an access to the backing file since the
+ * COW pages should be mapped in read-write
+ */
+
+ if(fd == dev->fd)
+ panic("Write fault on a backing page of ubd "
+ "device %d\n", i);
+
+ /* So, we do the write, copying the backing data to the COW
+ * file...
+ */
+
+ err = os_seek_file(dev->fd, offset + dev->cow.data_offset);
+ if(err < 0)
+ panic("Couldn't seek to %lld in COW file of ubd "
+ "device %d, err = %d",
+ offset + dev->cow.data_offset, i, -err);
+
+ n = os_write_file(dev->fd, (void *) address, PAGE_SIZE);
+ if(n != PAGE_SIZE)
+ panic("Couldn't copy data to COW file of ubd "
+ "device %d, err = %d", i, -n);
+
+ /* ... updating the COW bitmap... */
+
+ cowify_bitmap(offset, PAGE_SIZE, NULL, &bitmap_offset,
+ dev->cow.bitmap, dev->cow.bitmap_offset,
+ new_bitmap, dev->cow.bitmap_len);
+
+ err = os_seek_file(dev->fd, bitmap_offset);
+ if(err < 0)
+ panic("Couldn't seek to %lld in COW file of ubd "
+ "device %d, err = %d", bitmap_offset, i, -err);
+
+ n = os_write_file(dev->fd, new_bitmap, sizeof(new_bitmap));
+ if(n != sizeof(new_bitmap))
+ panic("Couldn't update bitmap of ubd device %d, "
+ "err = %d", i, -n);
+
+ /* Maybe we can map the COW page in, and maybe we can't. If
+ * it is a pre-V3 COW file, we can't, since the alignment will
+ * be wrong. If it is a V3 or later COW file which has been
+ * moved to a system with a larger page size, then maybe we
+ * can't, depending on the exact location of the page.
+ */
+
+ offset += dev->cow.data_offset;
+
+ /* Remove the remapping, putting the original anonymous page
+ * back. If the COW file can be mapped in, that is done.
+ * Otherwise, the COW page is read in.
+ */
+
+ if(!physmem_remove_mapping((void *) address))
+ panic("Address 0x%lx not remapped by ubd device %d",
+ address, i);
+ if((offset % UBD_MMAP_BLOCK_SIZE) == 0)
+ physmem_subst_mapping((void *) address, dev->fd,
+ offset, 1);
+ else {
+ err = os_seek_file(dev->fd, offset);
+ if(err < 0)
+ panic("Couldn't seek to %lld in COW file of "
+ "ubd device %d, err = %d", offset, i,
+ -err);
+
+ n = os_read_file(dev->fd, (void *) address, PAGE_SIZE);
+ if(n != PAGE_SIZE)
+ panic("Failed to read page from offset %llx of "
+ "COW file of ubd device %d, err = %d",
+ offset, i, -n);
+ }
+
+ return(1);
+ }
+
+ /* It's not a write on a ubd device */
+ return(0);
+}
+
+static struct remapper ubd_remapper = {
+ .list = LIST_HEAD_INIT(ubd_remapper.list),
+ .proc = ubd_check_remapped,
+};
+
+static int ubd_remapper_setup(void)
+{
+ if(ubd_do_mmap)
+ register_remapper(&ubd_remapper);
+
+ return(0);
+}
+
+__initcall(ubd_remapper_setup);
+
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
git://git.onelab.eu / linux-2.6.git / blobdiff