1670 lines
39 KiB
C
1670 lines
39 KiB
C
/*
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* Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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/* 2001-09-28...2002-04-17
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* Partition stuff by James_McMechan@hotmail.com
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* old style ubd by setting UBD_SHIFT to 0
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* 2002-09-27...2002-10-18 massive tinkering for 2.5
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* partitions have changed in 2.5
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* 2003-01-29 more tinkering for 2.5.59-1
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* This should now address the sysfs problems and has
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* the symlink for devfs to allow for booting with
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* the common /dev/ubd/discX/... names rather than
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* only /dev/ubdN/discN this version also has lots of
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* clean ups preparing for ubd-many.
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* James McMechan
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*/
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#define MAJOR_NR UBD_MAJOR
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#define UBD_SHIFT 4
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#include "linux/config.h"
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#include "linux/module.h"
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#include "linux/blkdev.h"
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#include "linux/hdreg.h"
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#include "linux/init.h"
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#include "linux/devfs_fs_kernel.h"
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#include "linux/cdrom.h"
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#include "linux/proc_fs.h"
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#include "linux/ctype.h"
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#include "linux/capability.h"
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#include "linux/mm.h"
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#include "linux/vmalloc.h"
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#include "linux/blkpg.h"
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#include "linux/genhd.h"
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#include "linux/spinlock.h"
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#include "asm/segment.h"
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#include "asm/uaccess.h"
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#include "asm/irq.h"
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#include "asm/types.h"
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#include "asm/tlbflush.h"
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#include "user_util.h"
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#include "mem_user.h"
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#include "kern_util.h"
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#include "kern.h"
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#include "mconsole_kern.h"
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#include "init.h"
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#include "irq_user.h"
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#include "irq_kern.h"
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#include "ubd_user.h"
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#include "2_5compat.h"
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#include "os.h"
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#include "mem.h"
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#include "mem_kern.h"
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#include "cow.h"
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enum ubd_req { UBD_READ, UBD_WRITE, UBD_MMAP };
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struct io_thread_req {
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enum ubd_req op;
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int fds[2];
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unsigned long offsets[2];
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unsigned long long offset;
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unsigned long length;
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char *buffer;
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int sectorsize;
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unsigned long sector_mask;
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unsigned long long cow_offset;
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unsigned long bitmap_words[2];
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int map_fd;
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unsigned long long map_offset;
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int error;
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};
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extern int open_ubd_file(char *file, struct openflags *openflags,
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char **backing_file_out, int *bitmap_offset_out,
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unsigned long *bitmap_len_out, int *data_offset_out,
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int *create_cow_out);
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extern int create_cow_file(char *cow_file, char *backing_file,
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struct openflags flags, int sectorsize,
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int alignment, int *bitmap_offset_out,
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unsigned long *bitmap_len_out,
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int *data_offset_out);
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extern int read_cow_bitmap(int fd, void *buf, int offset, int len);
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extern void do_io(struct io_thread_req *req);
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static inline int ubd_test_bit(__u64 bit, unsigned char *data)
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{
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__u64 n;
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int bits, off;
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bits = sizeof(data[0]) * 8;
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n = bit / bits;
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off = bit % bits;
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return((data[n] & (1 << off)) != 0);
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}
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static inline void ubd_set_bit(__u64 bit, unsigned char *data)
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{
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__u64 n;
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int bits, off;
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bits = sizeof(data[0]) * 8;
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n = bit / bits;
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off = bit % bits;
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data[n] |= (1 << off);
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}
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/*End stuff from ubd_user.h*/
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#define DRIVER_NAME "uml-blkdev"
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static DEFINE_SPINLOCK(ubd_io_lock);
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static DEFINE_SPINLOCK(ubd_lock);
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static void (*do_ubd)(void);
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static int ubd_open(struct inode * inode, struct file * filp);
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static int ubd_release(struct inode * inode, struct file * file);
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static int ubd_ioctl(struct inode * inode, struct file * file,
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unsigned int cmd, unsigned long arg);
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#define MAX_DEV (8)
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/* Changed in early boot */
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static int ubd_do_mmap = 0;
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#define UBD_MMAP_BLOCK_SIZE PAGE_SIZE
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static struct block_device_operations ubd_blops = {
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.owner = THIS_MODULE,
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.open = ubd_open,
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.release = ubd_release,
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.ioctl = ubd_ioctl,
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};
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/* Protected by the queue_lock */
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static request_queue_t *ubd_queue;
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/* Protected by ubd_lock */
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static int fake_major = MAJOR_NR;
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static struct gendisk *ubd_gendisk[MAX_DEV];
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static struct gendisk *fake_gendisk[MAX_DEV];
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#ifdef CONFIG_BLK_DEV_UBD_SYNC
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#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
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.cl = 1 })
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#else
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#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
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.cl = 1 })
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#endif
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/* Not protected - changed only in ubd_setup_common and then only to
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* to enable O_SYNC.
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*/
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static struct openflags global_openflags = OPEN_FLAGS;
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struct cow {
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char *file;
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int fd;
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unsigned long *bitmap;
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unsigned long bitmap_len;
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int bitmap_offset;
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int data_offset;
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};
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struct ubd {
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char *file;
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int count;
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int fd;
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__u64 size;
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struct openflags boot_openflags;
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struct openflags openflags;
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int no_cow;
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struct cow cow;
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struct platform_device pdev;
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int map_writes;
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int map_reads;
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int nomap_writes;
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int nomap_reads;
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int write_maps;
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};
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#define DEFAULT_COW { \
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.file = NULL, \
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.fd = -1, \
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.bitmap = NULL, \
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.bitmap_offset = 0, \
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.data_offset = 0, \
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}
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#define DEFAULT_UBD { \
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.file = NULL, \
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.count = 0, \
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.fd = -1, \
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.size = -1, \
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.boot_openflags = OPEN_FLAGS, \
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.openflags = OPEN_FLAGS, \
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.no_cow = 0, \
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.cow = DEFAULT_COW, \
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.map_writes = 0, \
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.map_reads = 0, \
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.nomap_writes = 0, \
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.nomap_reads = 0, \
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.write_maps = 0, \
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}
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struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD };
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static int ubd0_init(void)
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{
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struct ubd *dev = &ubd_dev[0];
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if(dev->file == NULL)
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dev->file = "root_fs";
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return(0);
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}
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__initcall(ubd0_init);
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/* Only changed by fake_ide_setup which is a setup */
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static int fake_ide = 0;
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static struct proc_dir_entry *proc_ide_root = NULL;
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static struct proc_dir_entry *proc_ide = NULL;
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static void make_proc_ide(void)
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{
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proc_ide_root = proc_mkdir("ide", NULL);
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proc_ide = proc_mkdir("ide0", proc_ide_root);
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}
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static int proc_ide_read_media(char *page, char **start, off_t off, int count,
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int *eof, void *data)
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{
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int len;
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strcpy(page, "disk\n");
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len = strlen("disk\n");
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len -= off;
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if (len < count){
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*eof = 1;
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if (len <= 0) return 0;
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}
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else len = count;
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*start = page + off;
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return len;
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}
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static void make_ide_entries(char *dev_name)
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{
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struct proc_dir_entry *dir, *ent;
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char name[64];
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if(proc_ide_root == NULL) make_proc_ide();
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dir = proc_mkdir(dev_name, proc_ide);
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if(!dir) return;
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ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir);
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if(!ent) return;
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ent->nlink = 1;
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ent->data = NULL;
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ent->read_proc = proc_ide_read_media;
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ent->write_proc = NULL;
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sprintf(name,"ide0/%s", dev_name);
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proc_symlink(dev_name, proc_ide_root, name);
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}
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static int fake_ide_setup(char *str)
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{
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fake_ide = 1;
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return(1);
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}
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__setup("fake_ide", fake_ide_setup);
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__uml_help(fake_ide_setup,
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"fake_ide\n"
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" Create ide0 entries that map onto ubd devices.\n\n"
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);
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static int parse_unit(char **ptr)
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{
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char *str = *ptr, *end;
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int n = -1;
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if(isdigit(*str)) {
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n = simple_strtoul(str, &end, 0);
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if(end == str)
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return(-1);
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*ptr = end;
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}
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else if (('a' <= *str) && (*str <= 'h')) {
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n = *str - 'a';
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str++;
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*ptr = str;
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}
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return(n);
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}
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static int ubd_setup_common(char *str, int *index_out)
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{
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struct ubd *dev;
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struct openflags flags = global_openflags;
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char *backing_file;
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int n, err, i;
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if(index_out) *index_out = -1;
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n = *str;
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if(n == '='){
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char *end;
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int major;
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str++;
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if(!strcmp(str, "mmap")){
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CHOOSE_MODE(printk("mmap not supported by the ubd "
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"driver in tt mode\n"),
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ubd_do_mmap = 1);
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return(0);
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}
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if(!strcmp(str, "sync")){
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global_openflags = of_sync(global_openflags);
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return(0);
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}
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major = simple_strtoul(str, &end, 0);
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if((*end != '\0') || (end == str)){
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printk(KERN_ERR
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"ubd_setup : didn't parse major number\n");
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return(1);
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}
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err = 1;
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spin_lock(&ubd_lock);
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if(fake_major != MAJOR_NR){
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printk(KERN_ERR "Can't assign a fake major twice\n");
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goto out1;
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}
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fake_major = major;
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printk(KERN_INFO "Setting extra ubd major number to %d\n",
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major);
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err = 0;
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out1:
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spin_unlock(&ubd_lock);
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return(err);
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}
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n = parse_unit(&str);
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if(n < 0){
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printk(KERN_ERR "ubd_setup : couldn't parse unit number "
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"'%s'\n", str);
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return(1);
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}
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if(n >= MAX_DEV){
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printk(KERN_ERR "ubd_setup : index %d out of range "
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"(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1);
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return(1);
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}
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err = 1;
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spin_lock(&ubd_lock);
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dev = &ubd_dev[n];
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if(dev->file != NULL){
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printk(KERN_ERR "ubd_setup : device already configured\n");
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goto out;
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}
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if (index_out)
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*index_out = n;
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for (i = 0; i < 4; i++) {
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switch (*str) {
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case 'r':
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flags.w = 0;
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break;
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case 's':
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flags.s = 1;
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break;
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case 'd':
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dev->no_cow = 1;
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break;
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case '=':
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str++;
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goto break_loop;
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default:
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printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r,s or d)\n");
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goto out;
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}
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str++;
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}
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if (*str == '=')
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printk(KERN_ERR "ubd_setup : Too many flags specified\n");
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else
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printk(KERN_ERR "ubd_setup : Expected '='\n");
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goto out;
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break_loop:
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err = 0;
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backing_file = strchr(str, ',');
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if (!backing_file) {
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backing_file = strchr(str, ':');
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}
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if(backing_file){
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if(dev->no_cow)
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printk(KERN_ERR "Can't specify both 'd' and a "
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"cow file\n");
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else {
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*backing_file = '\0';
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backing_file++;
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}
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}
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dev->file = str;
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dev->cow.file = backing_file;
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dev->boot_openflags = flags;
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out:
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spin_unlock(&ubd_lock);
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return(err);
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}
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static int ubd_setup(char *str)
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{
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ubd_setup_common(str, NULL);
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return(1);
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}
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__setup("ubd", ubd_setup);
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__uml_help(ubd_setup,
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"ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
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" This is used to associate a device with a file in the underlying\n"
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" filesystem. When specifying two filenames, the first one is the\n"
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" COW name and the second is the backing file name. As separator you can\n"
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" use either a ':' or a ',': the first one allows writing things like;\n"
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" ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
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" while with a ',' the shell would not expand the 2nd '~'.\n"
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" When using only one filename, UML will detect whether to thread it like\n"
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" a COW file or a backing file. To override this detection, add the 'd'\n"
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" flag:\n"
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" ubd0d=BackingFile\n"
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" Usually, there is a filesystem in the file, but \n"
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" that's not required. Swap devices containing swap files can be\n"
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" specified like this. Also, a file which doesn't contain a\n"
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" filesystem can have its contents read in the virtual \n"
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" machine by running 'dd' on the device. <n> must be in the range\n"
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" 0 to 7. Appending an 'r' to the number will cause that device\n"
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" to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
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" an 's' will cause data to be written to disk on the host immediately.\n\n"
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);
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static int udb_setup(char *str)
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{
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printk("udb%s specified on command line is almost certainly a ubd -> "
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"udb TYPO\n", str);
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return(1);
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}
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__setup("udb", udb_setup);
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__uml_help(udb_setup,
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"udb\n"
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" This option is here solely to catch ubd -> udb typos, which can be\n\n"
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" to impossible to catch visually unless you specifically look for\n\n"
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" them. The only result of any option starting with 'udb' is an error\n\n"
|
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" in the boot output.\n\n"
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);
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|
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static int fakehd_set = 0;
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static int fakehd(char *str)
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{
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printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n");
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fakehd_set = 1;
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return 1;
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}
|
|
|
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__setup("fakehd", fakehd);
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__uml_help(fakehd,
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|
"fakehd\n"
|
|
" Change the ubd device name to \"hd\".\n\n"
|
|
);
|
|
|
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static void do_ubd_request(request_queue_t * q);
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|
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/* Only changed by ubd_init, which is an initcall. */
|
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int thread_fd = -1;
|
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|
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/* Changed by ubd_handler, which is serialized because interrupts only
|
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* happen on CPU 0.
|
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*/
|
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int intr_count = 0;
|
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|
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/* call ubd_finish if you need to serialize */
|
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static void __ubd_finish(struct request *req, int error)
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{
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int nsect;
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|
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if(error){
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end_request(req, 0);
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return;
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}
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nsect = req->current_nr_sectors;
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req->sector += nsect;
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req->buffer += nsect << 9;
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req->errors = 0;
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req->nr_sectors -= nsect;
|
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req->current_nr_sectors = 0;
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end_request(req, 1);
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}
|
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|
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static inline void ubd_finish(struct request *req, int error)
|
|
{
|
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spin_lock(&ubd_io_lock);
|
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__ubd_finish(req, error);
|
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spin_unlock(&ubd_io_lock);
|
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}
|
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|
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/* Called without ubd_io_lock held */
|
|
static void ubd_handler(void)
|
|
{
|
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struct io_thread_req req;
|
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struct request *rq = elv_next_request(ubd_queue);
|
|
int n, err;
|
|
|
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do_ubd = NULL;
|
|
intr_count++;
|
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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;
|
|
}
|
|
|
|
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 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)
|
|
{
|
|
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;
|
|
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_remove(char *str)
|
|
{
|
|
struct ubd *dev;
|
|
int n, err = -ENODEV;
|
|
|
|
n = parse_unit(&str);
|
|
|
|
if((n < 0) || (n >= MAX_DEV))
|
|
return(err);
|
|
|
|
dev = &ubd_dev[n];
|
|
if(dev->count > 0)
|
|
return(-EBUSY); /* you cannot remove a open disk */
|
|
|
|
err = 0;
|
|
spin_lock(&ubd_lock);
|
|
|
|
if(ubd_gendisk[n] == NULL)
|
|
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,
|
|
.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++;
|
|
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);
|
|
}
|
|
|
|
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 offset;
|
|
int len, fd;
|
|
|
|
if(req->rq_status == RQ_INACTIVE) return(1);
|
|
|
|
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->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->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 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);
|
|
|
|
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, §orsize, &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;
|
|
|
|
if(req->op == UBD_MMAP){
|
|
/* Touch the page to force the host to do any necessary IO to
|
|
* get it into memory
|
|
*/
|
|
n = *((volatile int *) req->buffer);
|
|
req->error = update_bitmap(req);
|
|
return;
|
|
}
|
|
|
|
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:
|
|
*/
|