From: Jeff Dike <jdike@addtoit.com>
The code is still there but it's not built. Below is a patch which removes
it totally.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/um/Kconfig_block | 12
25-akpm/arch/um/drivers/Makefile | 1
25-akpm/arch/um/drivers/cow_kern.c | 630 -------------------------------------
3 files changed, 1 insertion(+), 642 deletions(-)
diff -puN arch/um/drivers/cow_kern.c~uml-remove-cow-driver arch/um/drivers/cow_kern.c
--- 25/arch/um/drivers/cow_kern.c~uml-remove-cow-driver Tue Aug 17 15:52:00 2004
+++ 25-akpm/arch/um/drivers/cow_kern.c Tue Aug 17 15:52:00 2004
@@ -1,630 +0,0 @@
-#define COW_MAJOR 60
-#define MAJOR_NR COW_MAJOR
-
-#include <linux/stddef.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/stat.h>
-#include <linux/vmalloc.h>
-#include <linux/blkdev.h>
-#include <linux/blk.h>
-#include <linux/fs.h>
-#include <linux/genhd.h>
-#include <linux/devfs_fs.h>
-#include <asm/uaccess.h>
-#include "2_5compat.h"
-#include "cow.h"
-#include "ubd_user.h"
-
-#define COW_SHIFT 4
-
-struct cow {
- int count;
- char *cow_path;
- dev_t cow_dev;
- struct block_device *cow_bdev;
- char *backing_path;
- dev_t backing_dev;
- struct block_device *backing_bdev;
- int sectorsize;
- unsigned long *bitmap;
- unsigned long bitmap_len;
- int bitmap_offset;
- int data_offset;
- devfs_handle_t devfs;
- struct semaphore sem;
- struct semaphore io_sem;
- atomic_t working;
- spinlock_t io_lock;
- struct buffer_head *bh;
- struct buffer_head *bhtail;
- void *end_io;
-};
-
-#define DEFAULT_COW { \
- .count = 0, \
- .cow_path = NULL, \
- .cow_dev = 0, \
- .backing_path = NULL, \
- .backing_dev = 0, \
- .bitmap = NULL, \
- .bitmap_len = 0, \
- .bitmap_offset = 0, \
- .data_offset = 0, \
- .devfs = NULL, \
- .working = ATOMIC_INIT(0), \
- .io_lock = SPIN_LOCK_UNLOCKED, \
-}
-
-#define MAX_DEV (8)
-#define MAX_MINOR (MAX_DEV << COW_SHIFT)
-
-struct cow cow_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_COW };
-
-/* Not modified by this driver */
-static int blk_sizes[MAX_MINOR] = { [ 0 ... MAX_MINOR - 1 ] = BLOCK_SIZE };
-static int hardsect_sizes[MAX_MINOR] = { [ 0 ... MAX_MINOR - 1 ] = 512 };
-
-/* Protected by cow_lock */
-static int sizes[MAX_MINOR] = { [ 0 ... MAX_MINOR - 1 ] = 0 };
-
-static struct hd_struct cow_part[MAX_MINOR] =
- { [ 0 ... MAX_MINOR - 1 ] = { 0, 0, 0 } };
-
-/* Protected by io_request_lock */
-static request_queue_t *cow_queue;
-
-static int cow_open(struct inode *inode, struct file *filp);
-static int cow_release(struct inode * inode, struct file * file);
-static int cow_ioctl(struct inode * inode, struct file * file,
- unsigned int cmd, unsigned long arg);
-static int cow_revalidate(kdev_t rdev);
-
-static struct block_device_operations cow_blops = {
- .open = cow_open,
- .release = cow_release,
- .ioctl = cow_ioctl,
- .revalidate = cow_revalidate,
-};
-
-/* Initialized in an initcall, and unchanged thereafter */
-devfs_handle_t cow_dir_handle;
-
-#define INIT_GENDISK(maj, name, parts, shift, bsizes, max, blops) \
-{ \
- .major = maj, \
- .major_name = name, \
- .minor_shift = shift, \
- .max_p = 1 << shift, \
- .part = parts, \
- .sizes = bsizes, \
- .nr_real = max, \
- .real_devices = NULL, \
- .next = NULL, \
- .fops = blops, \
- .de_arr = NULL, \
- .flags = 0 \
-}
-
-static spinlock_t cow_lock = SPIN_LOCK_UNLOCKED;
-
-static struct gendisk cow_gendisk = INIT_GENDISK(MAJOR_NR, "cow", cow_part,
- COW_SHIFT, sizes, MAX_DEV,
- &cow_blops);
-
-static int cow_add(int n)
-{
- struct cow *dev = &cow_dev[n];
- char name[sizeof("nnnnnn\0")];
- int err = -ENODEV;
-
- if(dev->cow_path == NULL)
- goto out;
-
- sprintf(name, "%d", n);
- dev->devfs = devfs_register(cow_dir_handle, name, DEVFS_FL_REMOVABLE,
- MAJOR_NR, n << COW_SHIFT, S_IFBLK |
- S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP,
- &cow_blops, NULL);
-
- init_MUTEX_LOCKED(&dev->sem);
- init_MUTEX(&dev->io_sem);
-
- return(0);
-
- out:
- return(err);
-}
-
-/*
- * Add buffer_head to back of pending list
- */
-static void cow_add_bh(struct cow *cow, struct buffer_head *bh)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&cow->io_lock, flags);
- if(cow->bhtail != NULL){
- cow->bhtail->b_reqnext = bh;
- cow->bhtail = bh;
- }
- else {
- cow->bh = bh;
- cow->bhtail = bh;
- }
- spin_unlock_irqrestore(&cow->io_lock, flags);
-}
-
-/*
-* Grab first pending buffer
-*/
-static struct buffer_head *cow_get_bh(struct cow *cow)
-{
- struct buffer_head *bh;
-
- spin_lock_irq(&cow->io_lock);
- bh = cow->bh;
- if(bh != NULL){
- if(bh == cow->bhtail)
- cow->bhtail = NULL;
- cow->bh = bh->b_reqnext;
- bh->b_reqnext = NULL;
- }
- spin_unlock_irq(&cow->io_lock);
-
- return(bh);
-}
-
-static void cow_handle_bh(struct cow *cow, struct buffer_head *bh,
- struct buffer_head **cow_bh, int ncow_bh)
-{
- int i;
-
- if(ncow_bh > 0)
- ll_rw_block(WRITE, ncow_bh, cow_bh);
-
- for(i = 0; i < ncow_bh ; i++){
- wait_on_buffer(cow_bh[i]);
- brelse(cow_bh[i]);
- }
-
- ll_rw_block(WRITE, 1, &bh);
- brelse(bh);
-}
-
-static struct buffer_head *cow_new_bh(struct cow *dev, int sector)
-{
- struct buffer_head *bh;
-
- sector = (dev->bitmap_offset + sector / 8) / dev->sectorsize;
- bh = getblk(dev->cow_dev, sector, dev->sectorsize);
- memcpy(bh->b_data, dev->bitmap + sector / (8 * sizeof(dev->bitmap[0])),
- dev->sectorsize);
- return(bh);
-}
-
-/* Copied from loop.c, needed to avoid deadlocking in make_request. */
-
-static int cow_thread(void *data)
-{
- struct cow *dev = data;
- struct buffer_head *bh;
-
- daemonize();
- exit_files(current);
-
- sprintf(current->comm, "cow%d", dev - cow_dev);
-
- spin_lock_irq(¤t->sigmask_lock);
- sigfillset(¤t->blocked);
- flush_signals(current);
- spin_unlock_irq(¤t->sigmask_lock);
-
- atomic_inc(&dev->working);
-
- current->policy = SCHED_OTHER;
- current->nice = -20;
-
- current->flags |= PF_NOIO;
-
- /*
- * up sem, we are running
- */
- up(&dev->sem);
-
- for(;;){
- int start, len, nbh, i, update_bitmap = 0;
- struct buffer_head *cow_bh[2];
-
- down_interruptible(&dev->io_sem);
- /*
- * could be upped because of tear-down, not because of
- * pending work
- */
- if(!atomic_read(&dev->working))
- break;
-
- bh = cow_get_bh(dev);
- if(bh == NULL){
- printk(KERN_ERR "cow: missing bh\n");
- continue;
- }
-
- start = bh->b_blocknr * bh->b_size / dev->sectorsize;
- len = bh->b_size / dev->sectorsize;
- for(i = 0; i < len ; i++){
- if(ubd_test_bit(start + i,
- (unsigned char *) dev->bitmap))
- continue;
-
- update_bitmap = 1;
- ubd_set_bit(start + i, (unsigned char *) dev->bitmap);
- }
-
- cow_bh[0] = NULL;
- cow_bh[1] = NULL;
- nbh = 0;
- if(update_bitmap){
- cow_bh[0] = cow_new_bh(dev, start);
- nbh++;
- if(start / dev->sectorsize !=
- (start + len) / dev->sectorsize){
- cow_bh[1] = cow_new_bh(dev, start + len);
- nbh++;
- }
- }
-
- bh->b_dev = dev->cow_dev;
- bh->b_blocknr += dev->data_offset / dev->sectorsize;
-
- cow_handle_bh(dev, bh, cow_bh, nbh);
-
- /*
- * upped both for pending work and tear-down, lo_pending
- * will hit zero then
- */
- if(atomic_dec_and_test(&dev->working))
- break;
- }
-
- up(&dev->sem);
- return(0);
-}
-
-static int cow_make_request(request_queue_t *q, int rw, struct buffer_head *bh)
-{
- struct cow *dev;
- int n, minor;
-
- minor = MINOR(bh->b_rdev);
- n = minor >> COW_SHIFT;
- dev = &cow_dev[n];
-
- dev->end_io = NULL;
- if(ubd_test_bit(bh->b_rsector, (unsigned char *) dev->bitmap)){
- bh->b_rdev = dev->cow_dev;
- bh->b_rsector += dev->data_offset / dev->sectorsize;
- }
- else if(rw == WRITE){
- bh->b_dev = dev->cow_dev;
- bh->b_blocknr += dev->data_offset / dev->sectorsize;
-
- cow_add_bh(dev, bh);
- up(&dev->io_sem);
- return(0);
- }
- else {
- bh->b_rdev = dev->backing_dev;
- }
-
- return(1);
-}
-
-int cow_init(void)
-{
- int i;
-
- cow_dir_handle = devfs_mk_dir (NULL, "cow", NULL);
- if (devfs_register_blkdev(MAJOR_NR, "cow", &cow_blops)) {
- printk(KERN_ERR "cow: unable to get major %d\n", MAJOR_NR);
- return -1;
- }
- read_ahead[MAJOR_NR] = 8; /* 8 sector (4kB) read-ahead */
- blksize_size[MAJOR_NR] = blk_sizes;
- blk_size[MAJOR_NR] = sizes;
- INIT_HARDSECT(hardsect_size, MAJOR_NR, hardsect_sizes);
-
- cow_queue = BLK_DEFAULT_QUEUE(MAJOR_NR);
- blk_init_queue(cow_queue, NULL);
- INIT_ELV(cow_queue, &cow_queue->elevator);
- blk_queue_make_request(cow_queue, cow_make_request);
-
- add_gendisk(&cow_gendisk);
-
- for(i=0;i<MAX_DEV;i++)
- cow_add(i);
-
- return(0);
-}
-
-__initcall(cow_init);
-
-static int reader(__u64 start, char *buf, int count, void *arg)
-{
- dev_t dev = *((dev_t *) arg);
- struct buffer_head *bh;
- __u64 block;
- int cur, offset, left, n, blocksize = get_hardsect_size(dev);
-
- if(blocksize == 0)
- panic("Zero blocksize");
-
- block = start / blocksize;
- offset = start % blocksize;
- left = count;
- cur = 0;
- while(left > 0){
- n = (left > blocksize) ? blocksize : left;
-
- bh = bread(dev, block, (n < 512) ? 512 : n);
- if(bh == NULL)
- return(-EIO);
-
- n -= offset;
- memcpy(&buf[cur], bh->b_data + offset, n);
- block++;
- left -= n;
- cur += n;
- offset = 0;
- brelse(bh);
- }
-
- return(count);
-}
-
-static int cow_open(struct inode *inode, struct file *filp)
-{
- int (*dev_ioctl)(struct inode *, struct file *, unsigned int,
- unsigned long);
- mm_segment_t fs;
- struct cow *dev;
- __u64 size;
- __u32 version, align;
- time_t mtime;
- char *backing_file;
- int n, offset, err = 0;
-
- n = DEVICE_NR(inode->i_rdev);
- if(n >= MAX_DEV)
- return(-ENODEV);
- dev = &cow_dev[n];
- offset = n << COW_SHIFT;
-
- spin_lock(&cow_lock);
-
- if(dev->count == 0){
- dev->cow_dev = name_to_kdev_t(dev->cow_path);
- if(dev->cow_dev == 0){
- printk(KERN_ERR "cow_open - name_to_kdev_t(\"%s\") "
- "failed\n", dev->cow_path);
- err = -ENODEV;
- }
-
- dev->backing_dev = name_to_kdev_t(dev->backing_path);
- if(dev->backing_dev == 0){
- printk(KERN_ERR "cow_open - name_to_kdev_t(\"%s\") "
- "failed\n", dev->backing_path);
- err = -ENODEV;
- }
-
- if(err)
- goto out;
-
- dev->cow_bdev = bdget(dev->cow_dev);
- if(dev->cow_bdev == NULL){
- printk(KERN_ERR "cow_open - bdget(\"%s\") failed\n",
- dev->cow_path);
- err = -ENOMEM;
- }
- dev->backing_bdev = bdget(dev->backing_dev);
- if(dev->backing_bdev == NULL){
- printk(KERN_ERR "cow_open - bdget(\"%s\") failed\n",
- dev->backing_path);
- err = -ENOMEM;
- }
-
- if(err)
- goto out;
-
- err = blkdev_get(dev->cow_bdev, FMODE_READ|FMODE_WRITE, 0,
- BDEV_RAW);
- if(err){
- printk("cow_open - blkdev_get of COW device failed, "
- "error = %d\n", err);
- goto out;
- }
-
- err = blkdev_get(dev->backing_bdev, FMODE_READ, 0, BDEV_RAW);
- if(err){
- printk("cow_open - blkdev_get of backing device "
- "failed, error = %d\n", err);
- goto out;
- }
-
- err = read_cow_header(reader, &dev->cow_dev, &version,
- &backing_file, &mtime, &size,
- &dev->sectorsize, &align,
- &dev->bitmap_offset);
- if(err){
- printk(KERN_ERR "cow_open - read_cow_header failed, "
- "err = %d\n", err);
- goto out;
- }
-
- cow_sizes(version, size, dev->sectorsize, align,
- dev->bitmap_offset, &dev->bitmap_len,
- &dev->data_offset);
- dev->bitmap = (void *) vmalloc(dev->bitmap_len);
- if(dev->bitmap == NULL){
- err = -ENOMEM;
- printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
- goto out;
- }
- flush_tlb_kernel_vm();
-
- err = reader(dev->bitmap_offset, (char *) dev->bitmap,
- dev->bitmap_len, &dev->cow_dev);
- if(err < 0){
- printk(KERN_ERR "Failed to read COW bitmap\n");
- vfree(dev->bitmap);
- goto out;
- }
-
- dev_ioctl = dev->backing_bdev->bd_op->ioctl;
- fs = get_fs();
- set_fs(KERNEL_DS);
- err = (*dev_ioctl)(inode, filp, BLKGETSIZE,
- (unsigned long) &sizes[offset]);
- set_fs(fs);
- if(err){
- printk(KERN_ERR "cow_open - BLKGETSIZE failed, "
- "error = %d\n", err);
- goto out;
- }
-
- kernel_thread(cow_thread, dev,
- CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
- down(&dev->sem);
- }
- dev->count++;
- out:
- spin_unlock(&cow_lock);
- return(err);
-}
-
-static int cow_release(struct inode * inode, struct file * file)
-{
- struct cow *dev;
- int n, err;
-
- n = DEVICE_NR(inode->i_rdev);
- if(n >= MAX_DEV)
- return(-ENODEV);
- dev = &cow_dev[n];
-
- spin_lock(&cow_lock);
-
- if(--dev->count > 0)
- goto out;
-
- err = blkdev_put(dev->cow_bdev, BDEV_RAW);
- if(err)
- printk("cow_release - blkdev_put of cow device failed, "
- "error = %d\n", err);
- bdput(dev->cow_bdev);
- dev->cow_bdev = 0;
-
- err = blkdev_put(dev->backing_bdev, BDEV_RAW);
- if(err)
- printk("cow_release - blkdev_put of backing device failed, "
- "error = %d\n", err);
- bdput(dev->backing_bdev);
- dev->backing_bdev = 0;
-
- out:
- spin_unlock(&cow_lock);
- return(0);
-}
-
-static int cow_ioctl(struct inode * inode, struct file * file,
- unsigned int cmd, unsigned long arg)
-{
- struct cow *dev;
- int (*dev_ioctl)(struct inode *, struct file *, unsigned int,
- unsigned long);
- int n;
-
- n = DEVICE_NR(inode->i_rdev);
- if(n >= MAX_DEV)
- return(-ENODEV);
- dev = &cow_dev[n];
-
- dev_ioctl = dev->backing_bdev->bd_op->ioctl;
- return((*dev_ioctl)(inode, file, cmd, arg));
-}
-
-static int cow_revalidate(kdev_t rdev)
-{
- printk(KERN_ERR "Need to implement cow_revalidate\n");
- return(0);
-}
-
-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 cow_setup(char *str)
-{
- struct cow *dev;
- char *cow_name, *backing_name;
- int unit;
-
- unit = parse_unit(&str);
- if(unit < 0){
- printk(KERN_ERR "cow_setup - Couldn't parse unit number\n");
- return(1);
- }
-
- if(*str != '='){
- printk(KERN_ERR "cow_setup - Missing '=' after unit "
- "number\n");
- return(1);
- }
- str++;
-
- cow_name = str;
- backing_name = strchr(str, ',');
- if(backing_name == NULL){
- printk(KERN_ERR "cow_setup - missing backing device name\n");
- return(0);
- }
- *backing_name = '\0';
- backing_name++;
-
- spin_lock(&cow_lock);
-
- dev = &cow_dev[unit];
- dev->cow_path = cow_name;
- dev->backing_path = backing_name;
-
- spin_unlock(&cow_lock);
- return(0);
-}
-
-__setup("cow", cow_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
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff -puN arch/um/drivers/Makefile~uml-remove-cow-driver arch/um/drivers/Makefile
--- 25/arch/um/drivers/Makefile~uml-remove-cow-driver Tue Aug 17 15:52:00 2004
+++ 25-akpm/arch/um/drivers/Makefile Tue Aug 17 15:52:00 2004
@@ -39,7 +39,6 @@ obj-$(CONFIG_PTY_CHAN) += pty.o
obj-$(CONFIG_TTY_CHAN) += tty.o
obj-$(CONFIG_XTERM_CHAN) += xterm.o xterm_kern.o
obj-$(CONFIG_UML_WATCHDOG) += harddog.o
-obj-$(CONFIG_BLK_DEV_COW) += cow_kern.o
obj-$(CONFIG_BLK_DEV_COW_COMMON) += cow_user.o
obj-y += stdio_console.o $(CHAN_OBJS)
diff -puN arch/um/Kconfig_block~uml-remove-cow-driver arch/um/Kconfig_block
--- 25/arch/um/Kconfig_block~uml-remove-cow-driver Tue Aug 17 15:52:00 2004
+++ 25-akpm/arch/um/Kconfig_block Tue Aug 17 15:52:00 2004
@@ -29,19 +29,9 @@ config BLK_DEV_UBD_SYNC
wise choice too. In all other cases (for example, if you're just
playing around with User-Mode Linux) you can choose N.
-# Turn this back on when the driver actually works
-#
-#config BLK_DEV_COW
-# tristate "COW block device"
-# help
-# This is a layered driver which sits above two other block devices.
-# One is read-only, and the other is a read-write layer which stores
-# all changes. This provides the illusion that the read-only layer
-# can be mounted read-write and changed.
-
config BLK_DEV_COW_COMMON
bool
- default BLK_DEV_COW || BLK_DEV_UBD
+ default BLK_DEV_UBD
config BLK_DEV_LOOP
tristate "Loopback device support"
_