/* * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) * Licensed under the GPL */ /* 2001-09-28...2002-04-17 * Partition stuff by James_McMechan@hotmail.com * old style ubd by setting UBD_SHIFT to 0 * 2002-09-27...2002-10-18 massive tinkering for 2.5 * partitions have changed in 2.5 * 2003-01-29 more tinkering for 2.5.59-1 * This should now address the sysfs problems and has * the symlink for devfs to allow for booting with * the common /dev/ubd/discX/... names rather than * only /dev/ubdN/discN this version also has lots of * clean ups preparing for ubd-many. * James McMechan */ #define MAJOR_NR UBD_MAJOR #define UBD_SHIFT 4 #include "linux/module.h" #include "linux/blkdev.h" #include "linux/hdreg.h" #include "linux/init.h" #include "linux/cdrom.h" #include "linux/proc_fs.h" #include "linux/ctype.h" #include "linux/capability.h" #include "linux/mm.h" #include "linux/vmalloc.h" #include "linux/blkpg.h" #include "linux/genhd.h" #include "linux/spinlock.h" #include "linux/platform_device.h" #include "asm/segment.h" #include "asm/uaccess.h" #include "asm/irq.h" #include "asm/types.h" #include "asm/tlbflush.h" #include "user_util.h" #include "mem_user.h" #include "kern_util.h" #include "kern.h" #include "mconsole_kern.h" #include "init.h" #include "irq_user.h" #include "irq_kern.h" #include "ubd_user.h" #include "os.h" #include "mem.h" #include "mem_kern.h" #include "cow.h" enum ubd_req { UBD_READ, UBD_WRITE }; struct io_thread_req { enum ubd_req op; int fds[2]; unsigned long offsets[2]; unsigned long long offset; unsigned long length; char *buffer; int sectorsize; unsigned long sector_mask; unsigned long long cow_offset; unsigned long bitmap_words[2]; int error; }; extern int open_ubd_file(char *file, struct openflags *openflags, int shared, char **backing_file_out, int *bitmap_offset_out, unsigned long *bitmap_len_out, int *data_offset_out, int *create_cow_out); extern int create_cow_file(char *cow_file, char *backing_file, struct openflags flags, int sectorsize, int alignment, int *bitmap_offset_out, unsigned long *bitmap_len_out, int *data_offset_out); extern int read_cow_bitmap(int fd, void *buf, int offset, int len); extern void do_io(struct io_thread_req *req); static inline int ubd_test_bit(__u64 bit, unsigned char *data) { __u64 n; int bits, off; bits = sizeof(data[0]) * 8; n = bit / bits; off = bit % bits; return((data[n] & (1 << off)) != 0); } static inline void ubd_set_bit(__u64 bit, unsigned char *data) { __u64 n; int bits, off; bits = sizeof(data[0]) * 8; n = bit / bits; off = bit % bits; data[n] |= (1 << off); } /*End stuff from ubd_user.h*/ #define DRIVER_NAME "uml-blkdev" /* Can be taken in interrupt context, and is passed to the block layer to lock * the request queue. Kernel side code knows that. */ static DEFINE_SPINLOCK(ubd_io_lock); static DEFINE_MUTEX(ubd_lock); /* XXX - this made sense in 2.4 days, now it's only used as a boolean, and * probably it doesn't make sense even for that. */ static int do_ubd; static int ubd_open(struct inode * inode, struct file * filp); static int ubd_release(struct inode * inode, struct file * file); static int ubd_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg); static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); #define MAX_DEV (16) static struct block_device_operations ubd_blops = { .owner = THIS_MODULE, .open = ubd_open, .release = ubd_release, .ioctl = ubd_ioctl, .getgeo = ubd_getgeo, }; /* Protected by the queue_lock */ static request_queue_t *ubd_queue; /* Protected by ubd_lock */ static int fake_major = MAJOR_NR; static struct gendisk *ubd_gendisk[MAX_DEV]; static struct gendisk *fake_gendisk[MAX_DEV]; #ifdef CONFIG_BLK_DEV_UBD_SYNC #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ .cl = 1 }) #else #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ .cl = 1 }) #endif /* Not protected - changed only in ubd_setup_common and then only to * to enable O_SYNC. */ static struct openflags global_openflags = OPEN_FLAGS; struct cow { /* backing file name */ char *file; /* backing file fd */ int fd; unsigned long *bitmap; unsigned long bitmap_len; int bitmap_offset; int data_offset; }; struct ubd { /* name (and fd, below) of the file opened for writing, either the * backing or the cow file. */ char *file; int count; int fd; __u64 size; struct openflags boot_openflags; struct openflags openflags; int shared; int no_cow; struct cow cow; struct platform_device pdev; }; #define DEFAULT_COW { \ .file = NULL, \ .fd = -1, \ .bitmap = NULL, \ .bitmap_offset = 0, \ .data_offset = 0, \ } #define DEFAULT_UBD { \ .file = NULL, \ .count = 0, \ .fd = -1, \ .size = -1, \ .boot_openflags = OPEN_FLAGS, \ .openflags = OPEN_FLAGS, \ .no_cow = 0, \ .shared = 0, \ .cow = DEFAULT_COW, \ } struct ubd ubd_devs[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; static int ubd0_init(void) { struct ubd *ubd_dev = &ubd_devs[0]; if(ubd_dev->file == NULL) ubd_dev->file = "root_fs"; return(0); } __initcall(ubd0_init); /* Only changed by fake_ide_setup which is a setup */ static int fake_ide = 0; static struct proc_dir_entry *proc_ide_root = NULL; static struct proc_dir_entry *proc_ide = NULL; static void make_proc_ide(void) { proc_ide_root = proc_mkdir("ide", NULL); proc_ide = proc_mkdir("ide0", proc_ide_root); } static int proc_ide_read_media(char *page, char **start, off_t off, int count, int *eof, void *data) { int len; strcpy(page, "disk\n"); len = strlen("disk\n"); len -= off; if (len < count){ *eof = 1; if (len <= 0) return 0; } else len = count; *start = page + off; return len; } static void make_ide_entries(char *dev_name) { struct proc_dir_entry *dir, *ent; char name[64]; if(proc_ide_root == NULL) make_proc_ide(); dir = proc_mkdir(dev_name, proc_ide); if(!dir) return; ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir); if(!ent) return; ent->nlink = 1; ent->data = NULL; ent->read_proc = proc_ide_read_media; ent->write_proc = NULL; sprintf(name,"ide0/%s", dev_name); proc_symlink(dev_name, proc_ide_root, name); } static int fake_ide_setup(char *str) { fake_ide = 1; return(1); } __setup("fake_ide", fake_ide_setup); __uml_help(fake_ide_setup, "fake_ide\n" " Create ide0 entries that map onto ubd devices.\n\n" ); static int parse_unit(char **ptr) { char *str = *ptr, *end; int n = -1; if(isdigit(*str)) { n = simple_strtoul(str, &end, 0); if(end == str) return(-1); *ptr = end; } else if (('a' <= *str) && (*str <= 'z')) { n = *str - 'a'; str++; *ptr = str; } return(n); } static int ubd_setup_common(char *str, int *index_out) { struct ubd *ubd_dev; struct openflags flags = global_openflags; char *backing_file; int n, err, i; if(index_out) *index_out = -1; n = *str; if(n == '='){ char *end; int major; str++; if(!strcmp(str, "sync")){ global_openflags = of_sync(global_openflags); return(0); } major = simple_strtoul(str, &end, 0); if((*end != '\0') || (end == str)){ printk(KERN_ERR "ubd_setup : didn't parse major number\n"); return(1); } err = 1; mutex_lock(&ubd_lock); if(fake_major != MAJOR_NR){ printk(KERN_ERR "Can't assign a fake major twice\n"); goto out1; } fake_major = major; printk(KERN_INFO "Setting extra ubd major number to %d\n", major); err = 0; out1: mutex_unlock(&ubd_lock); return(err); } n = parse_unit(&str); if(n < 0){ printk(KERN_ERR "ubd_setup : couldn't parse unit number " "'%s'\n", str); return(1); } if(n >= MAX_DEV){ printk(KERN_ERR "ubd_setup : index %d out of range " "(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1); return(1); } err = 1; mutex_lock(&ubd_lock); ubd_dev = &ubd_devs[n]; if(ubd_dev->file != NULL){ printk(KERN_ERR "ubd_setup : device already configured\n"); goto out; } if (index_out) *index_out = n; for (i = 0; i < sizeof("rscd="); i++) { switch (*str) { case 'r': flags.w = 0; break; case 's': flags.s = 1; break; case 'd': ubd_dev->no_cow = 1; break; case 'c': ubd_dev->shared = 1; break; case '=': str++; goto break_loop; default: printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r, s, c, or d)\n"); goto out; } str++; } if (*str == '=') printk(KERN_ERR "ubd_setup : Too many flags specified\n"); else printk(KERN_ERR "ubd_setup : Expected '='\n"); goto out; break_loop: err = 0; backing_file = strchr(str, ','); if (!backing_file) { backing_file = strchr(str, ':'); } if(backing_file){ if(ubd_dev->no_cow) printk(KERN_ERR "Can't specify both 'd' and a " "cow file\n"); else { *backing_file = '\0'; backing_file++; } } ubd_dev->file = str; ubd_dev->cow.file = backing_file; ubd_dev->boot_openflags = flags; out: mutex_unlock(&ubd_lock); return(err); } static int ubd_setup(char *str) { ubd_setup_common(str, NULL); return(1); } __setup("ubd", ubd_setup); __uml_help(ubd_setup, "ubd<n><flags>=<filename>[(:|,)<filename2>]\n" " This is used to associate a device with a file in the underlying\n" " filesystem. When specifying two filenames, the first one is the\n" " COW name and the second is the backing file name. As separator you can\n" " use either a ':' or a ',': the first one allows writing things like;\n" " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" " while with a ',' the shell would not expand the 2nd '~'.\n" " When using only one filename, UML will detect whether to thread it like\n" " a COW file or a backing file. To override this detection, add the 'd'\n" " flag:\n" " ubd0d=BackingFile\n" " Usually, there is a filesystem in the file, but \n" " that's not required. Swap devices containing swap files can be\n" " specified like this. Also, a file which doesn't contain a\n" " filesystem can have its contents read in the virtual \n" " machine by running 'dd' on the device. <n> must be in the range\n" " 0 to 7. Appending an 'r' to the number will cause that device\n" " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" " an 's' will cause data to be written to disk on the host immediately.\n\n" ); static int udb_setup(char *str) { printk("udb%s specified on command line is almost certainly a ubd -> " "udb TYPO\n", str); return(1); } __setup("udb", udb_setup); __uml_help(udb_setup, "udb\n" " This option is here solely to catch ubd -> udb typos, which can be\n" " to impossible to catch visually unless you specifically look for\n" " them. The only result of any option starting with 'udb' is an error\n" " in the boot output.\n\n" ); static int fakehd_set = 0; static int fakehd(char *str) { printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n"); fakehd_set = 1; return 1; } __setup("fakehd", fakehd); __uml_help(fakehd, "fakehd\n" " Change the ubd device name to \"hd\".\n\n" ); static void do_ubd_request(request_queue_t * q); /* Only changed by ubd_init, which is an initcall. */ int thread_fd = -1; /* Changed by ubd_handler, which is serialized because interrupts only * happen on CPU 0. */ int intr_count = 0; /* call ubd_finish if you need to serialize */ static void __ubd_finish(struct request *req, int error) { int nsect; if(error){ end_request(req, 0); return; } nsect = req->current_nr_sectors; req->sector += nsect; req->buffer += nsect << 9; req->errors = 0; req->nr_sectors -= nsect; req->current_nr_sectors = 0; end_request(req, 1); } /* Callable only from interrupt context - otherwise you need to do * spin_lock_irq()/spin_lock_irqsave() */ static inline void ubd_finish(struct request *req, int error) { spin_lock(&ubd_io_lock); __ubd_finish(req, error); spin_unlock(&ubd_io_lock); } /* XXX - move this inside ubd_intr. */ /* Called without ubd_io_lock held, and only in interrupt context. */ static void ubd_handler(void) { struct io_thread_req req; struct request *rq = elv_next_request(ubd_queue); int n; do_ubd = 0; intr_count++; n = os_read_file(thread_fd, &req, sizeof(req)); if(n != sizeof(req)){ printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, " "err = %d\n", os_getpid(), -n); spin_lock(&ubd_io_lock); end_request(rq, 0); spin_unlock(&ubd_io_lock); return; } ubd_finish(rq, req.error); reactivate_fd(thread_fd, UBD_IRQ); spin_lock(&ubd_io_lock); do_ubd_request(ubd_queue); spin_unlock(&ubd_io_lock); } static irqreturn_t ubd_intr(int irq, void *dev) { ubd_handler(); return(IRQ_HANDLED); } /* Only changed by ubd_init, which is an initcall. */ static int io_pid = -1; 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 *ubd_dev, __u64 *size_out) { char *file; file = ubd_dev->cow.file ? ubd_dev->cow.file : ubd_dev->file; return(os_file_size(file, size_out)); } static void ubd_close_dev(struct ubd *ubd_dev) { os_close_file(ubd_dev->fd); if(ubd_dev->cow.file == NULL) return; os_close_file(ubd_dev->cow.fd); vfree(ubd_dev->cow.bitmap); ubd_dev->cow.bitmap = NULL; } static int ubd_open_dev(struct ubd *ubd_dev) { struct openflags flags; char **back_ptr; int err, create_cow, *create_ptr; ubd_dev->openflags = ubd_dev->boot_openflags; create_cow = 0; create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; ubd_dev->fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared, back_ptr, &ubd_dev->cow.bitmap_offset, &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset, create_ptr); if((ubd_dev->fd == -ENOENT) && create_cow){ ubd_dev->fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file, ubd_dev->openflags, 1 << 9, PAGE_SIZE, &ubd_dev->cow.bitmap_offset, &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset); if(ubd_dev->fd >= 0){ printk(KERN_INFO "Creating \"%s\" as COW file for " "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); } } if(ubd_dev->fd < 0){ printk("Failed to open '%s', errno = %d\n", ubd_dev->file, -ubd_dev->fd); return(ubd_dev->fd); } if(ubd_dev->cow.file != NULL){ err = -ENOMEM; ubd_dev->cow.bitmap = (void *) vmalloc(ubd_dev->cow.bitmap_len); if(ubd_dev->cow.bitmap == NULL){ printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); goto error; } flush_tlb_kernel_vm(); err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap, ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len); if(err < 0) goto error; flags = ubd_dev->openflags; flags.w = 0; err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, NULL, NULL, NULL, NULL); if(err < 0) goto error; ubd_dev->cow.fd = err; } return(0); error: os_close_file(ubd_dev->fd); return(err); } static int ubd_disk_register(int major, u64 size, int unit, struct gendisk **disk_out) { struct gendisk *disk; disk = alloc_disk(1 << UBD_SHIFT); if(disk == NULL) return(-ENOMEM); disk->major = major; disk->first_minor = unit << UBD_SHIFT; disk->fops = &ubd_blops; set_capacity(disk, size / 512); if(major == MAJOR_NR) sprintf(disk->disk_name, "ubd%c", 'a' + unit); else sprintf(disk->disk_name, "ubd_fake%d", unit); /* sysfs register (not for ide fake devices) */ if (major == MAJOR_NR) { ubd_devs[unit].pdev.id = unit; ubd_devs[unit].pdev.name = DRIVER_NAME; platform_device_register(&ubd_devs[unit].pdev); disk->driverfs_dev = &ubd_devs[unit].pdev.dev; } disk->private_data = &ubd_devs[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 *ubd_dev = &ubd_devs[n]; int err; err = -ENODEV; if(ubd_dev->file == NULL) goto out; err = ubd_file_size(ubd_dev, &ubd_dev->size); if(err < 0) goto out; ubd_dev->size = ROUND_BLOCK(ubd_dev->size); err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]); if(err) goto out; if(fake_major != MAJOR_NR) ubd_disk_register(fake_major, ubd_dev->size, n, &fake_gendisk[n]); /* perhaps this should also be under the "if (fake_major)" above */ /* using the fake_disk->disk_name and also the fakehd_set name */ if (fake_ide) make_ide_entries(ubd_gendisk[n]->disk_name); err = 0; out: return err; } static int ubd_config(char *str) { int n, err; str = kstrdup(str, GFP_KERNEL); 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); mutex_lock(&ubd_lock); err = ubd_add(n); if(err) ubd_devs[n].file = NULL; mutex_unlock(&ubd_lock); return(err); } static int ubd_get_config(char *name, char *str, int size, char **error_out) { struct ubd *ubd_dev; int n, len = 0; n = parse_unit(&name); if((n >= MAX_DEV) || (n < 0)){ *error_out = "ubd_get_config : device number out of range"; return(-1); } ubd_dev = &ubd_devs[n]; mutex_lock(&ubd_lock); if(ubd_dev->file == NULL){ CONFIG_CHUNK(str, size, len, "", 1); goto out; } CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); if(ubd_dev->cow.file != NULL){ CONFIG_CHUNK(str, size, len, ",", 0); CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1); } else CONFIG_CHUNK(str, size, len, "", 1); out: mutex_unlock(&ubd_lock); return(len); } static int ubd_id(char **str, int *start_out, int *end_out) { int n; n = parse_unit(str); *start_out = 0; *end_out = MAX_DEV - 1; return n; } static int ubd_remove(int n) { struct ubd *ubd_dev; int err = -ENODEV; mutex_lock(&ubd_lock); if(ubd_gendisk[n] == NULL) goto out; ubd_dev = &ubd_devs[n]; if(ubd_dev->file == NULL) goto out; /* you cannot remove a open disk */ err = -EBUSY; if(ubd_dev->count > 0) goto out; 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(&ubd_dev->pdev); *ubd_dev = ((struct ubd) DEFAULT_UBD); err = 0; out: mutex_unlock(&ubd_lock); return err; } static struct mc_device ubd_mc = { .name = "ubd", .config = ubd_config, .get_config = ubd_get_config, .id = ubd_id, .remove = ubd_remove, }; static int ubd_mc_init(void) { mconsole_register_dev(&ubd_mc); return 0; } __initcall(ubd_mc_init); static struct platform_driver ubd_driver = { .driver = { .name = DRIVER_NAME, }, }; int ubd_init(void) { int i; 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); if (register_blkdev(fake_major, "ubd")) return -1; } platform_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, IRQF_DISABLED, "ubd", ubd_devs); if(err != 0) printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); return 0; } device_initcall(ubd_driver_init); static int ubd_open(struct inode *inode, struct file *filp) { struct gendisk *disk = inode->i_bdev->bd_disk; struct ubd *ubd_dev = disk->private_data; int err = 0; if(ubd_dev->count == 0){ err = ubd_open_dev(ubd_dev); if(err){ printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", disk->disk_name, ubd_dev->file, -err); goto out; } } ubd_dev->count++; set_disk_ro(disk, !ubd_dev->openflags.w); /* This should no more be needed. And it didn't work anyway to exclude * read-write remounting of filesystems.*/ /*if((filp->f_mode & FMODE_WRITE) && !ubd_dev->openflags.w){ if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); err = -EROFS; }*/ out: return(err); } static int ubd_release(struct inode * inode, struct file * file) { struct gendisk *disk = inode->i_bdev->bd_disk; struct ubd *ubd_dev = disk->private_data; if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); return(0); } static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, __u64 *cow_offset, unsigned long *bitmap, __u64 bitmap_offset, unsigned long *bitmap_words, __u64 bitmap_len) { __u64 sector = io_offset >> 9; int i, update_bitmap = 0; for(i = 0; i < length >> 9; i++){ if(cow_mask != NULL) ubd_set_bit(i, (unsigned char *) cow_mask); if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) continue; update_bitmap = 1; ubd_set_bit(sector + i, (unsigned char *) bitmap); } if(!update_bitmap) return; *cow_offset = sector / (sizeof(unsigned long) * 8); /* This takes care of the case where we're exactly at the end of the * device, and *cow_offset + 1 is off the end. So, just back it up * by one word. Thanks to Lynn Kerby for the fix and James McMechan * for the original diagnosis. */ if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) / sizeof(unsigned long) - 1)) (*cow_offset)--; bitmap_words[0] = bitmap[*cow_offset]; bitmap_words[1] = bitmap[*cow_offset + 1]; *cow_offset *= sizeof(unsigned long); *cow_offset += bitmap_offset; } static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, __u64 bitmap_offset, __u64 bitmap_len) { __u64 sector = req->offset >> 9; int i; if(req->length > (sizeof(req->sector_mask) * 8) << 9) panic("Operation too long"); if(req->op == UBD_READ) { for(i = 0; i < req->length >> 9; i++){ if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) ubd_set_bit(i, (unsigned char *) &req->sector_mask); } } else cowify_bitmap(req->offset, req->length, &req->sector_mask, &req->cow_offset, bitmap, bitmap_offset, req->bitmap_words, bitmap_len); } /* Called with ubd_io_lock held */ static int prepare_request(struct request *req, struct io_thread_req *io_req) { struct gendisk *disk = req->rq_disk; struct ubd *ubd_dev = disk->private_data; __u64 offset; int len; /* This should be impossible now */ if((rq_data_dir(req) == WRITE) && !ubd_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] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd : ubd_dev->fd; io_req->fds[1] = ubd_dev->fd; io_req->cow_offset = -1; io_req->offset = offset; io_req->length = len; io_req->error = 0; io_req->sector_mask = 0; io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; io_req->offsets[0] = 0; io_req->offsets[1] = ubd_dev->cow.data_offset; io_req->buffer = req->buffer; io_req->sectorsize = 1 << 9; if(ubd_dev->cow.file != NULL) cowify_req(io_req, ubd_dev->cow.bitmap, ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len); 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 = 1; 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_getgeo(struct block_device *bdev, struct hd_geometry *geo) { struct ubd *ubd_dev = bdev->bd_disk->private_data; geo->heads = 128; geo->sectors = 32; geo->cylinders = ubd_dev->size / (128 * 32 * 512); return 0; } static int ubd_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg) { struct ubd *ubd_dev = inode->i_bdev->bd_disk->private_data; struct hd_driveid ubd_id = { .cyls = 0, .heads = 128, .sectors = 32, }; switch (cmd) { struct cdrom_volctrl volume; case HDIO_GET_IDENTITY: ubd_id.cyls = ubd_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 path_requires_switch(char *from_cmdline, char *from_cow, char *cow) { struct uml_stat buf1, buf2; int err; if(from_cmdline == NULL) return 0; if(!strcmp(from_cmdline, from_cow)) return 0; err = os_stat_file(from_cmdline, &buf1); if(err < 0){ printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err); return 0; } 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 0; printk("Backing file mismatch - \"%s\" requested,\n" "\"%s\" specified in COW header of \"%s\"\n", from_cmdline, from_cow, cow); return 1; } static int backing_file_mismatch(char *file, __u64 size, time_t mtime) { unsigned long modtime; unsigned long long actual; int err; err = os_file_modtime(file, &modtime); if(err < 0){ printk("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, int shared, char **backing_file_out, int *bitmap_offset_out, unsigned long *bitmap_len_out, int *data_offset_out, int *create_cow_out) { time_t mtime; unsigned long long size; __u32 version, align; char *backing_file; int fd, err, sectorsize, asked_switch, mode = 0644; fd = os_open_file(file, *openflags, mode); if (fd < 0) { if ((fd == -ENOENT) && (create_cow_out != NULL)) *create_cow_out = 1; if (!openflags->w || ((fd != -EROFS) && (fd != -EACCES))) return fd; openflags->w = 0; fd = os_open_file(file, *openflags, mode); if (fd < 0) return fd; } if(shared) printk("Not locking \"%s\" on the host\n", file); else { err = os_lock_file(fd, openflags->w); if(err < 0){ printk("Failed to lock '%s', err = %d\n", file, -err); goto out_close; } } /* Successful return case! */ if(backing_file_out == NULL) return(fd); err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, &size, §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); asked_switch = path_requires_switch(*backing_file_out, backing_file, file); /* Allow switching only if no mismatch. */ if (asked_switch && !backing_file_mismatch(*backing_file_out, size, mtime)) { printk("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); goto out_close; } } else { *backing_file_out = backing_file; err = backing_file_mismatch(*backing_file_out, size, mtime); if (err) goto out_close; } cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, bitmap_len_out, data_offset_out); return fd; out_close: os_close_file(fd); return err; } int create_cow_file(char *cow_file, char *backing_file, struct openflags flags, int sectorsize, int alignment, int *bitmap_offset_out, unsigned long *bitmap_len_out, int *data_offset_out) { int err, fd; flags.c = 1; fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); if(fd < 0){ err = fd; printk("Open of COW file '%s' failed, errno = %d\n", cow_file, -err); goto out; } err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, bitmap_offset_out, bitmap_len_out, data_offset_out); if(!err) return(fd); os_close_file(fd); out: return(err); } static int update_bitmap(struct io_thread_req *req) { int n; if(req->cow_offset == -1) return(0); n = os_seek_file(req->fds[1], req->cow_offset); if(n < 0){ printk("do_io - bitmap lseek failed : err = %d\n", -n); return(1); } n = os_write_file(req->fds[1], &req->bitmap_words, sizeof(req->bitmap_words)); if(n != sizeof(req->bitmap_words)){ printk("do_io - bitmap update failed, err = %d fd = %d\n", -n, req->fds[1]); return(1); } return(0); } void do_io(struct io_thread_req *req) { char *buf; unsigned long len; int n, nsectors, start, end, bit; int err; __u64 off; nsectors = req->length / req->sectorsize; start = 0; do { bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask); end = start; while((end < nsectors) && (ubd_test_bit(end, (unsigned char *) &req->sector_mask) == bit)) end++; off = req->offset + req->offsets[bit] + start * req->sectorsize; len = (end - start) * req->sectorsize; buf = &req->buffer[start * req->sectorsize]; err = os_seek_file(req->fds[bit], off); if(err < 0){ printk("do_io - lseek failed : err = %d\n", -err); req->error = 1; return; } if(req->op == UBD_READ){ n = 0; do { buf = &buf[n]; len -= n; n = os_read_file(req->fds[bit], buf, len); if (n < 0) { printk("do_io - read failed, err = %d " "fd = %d\n", -n, req->fds[bit]); req->error = 1; return; } } while((n < len) && (n != 0)); if (n < len) memset(&buf[n], 0, len - n); } else { n = os_write_file(req->fds[bit], buf, len); if(n != len){ printk("do_io - write failed err = %d " "fd = %d\n", -n, req->fds[bit]); req->error = 1; return; } } start = end; } while(start < nsectors); req->error = update_bitmap(req); } /* Changed in start_io_thread, which is serialized by being called only * from ubd_init, which is an initcall. */ int kernel_fd = -1; /* Only changed by the io thread */ int io_count = 0; int io_thread(void *arg) { struct io_thread_req req; int n; ignore_sigwinch_sig(); while(1){ n = os_read_file(kernel_fd, &req, sizeof(req)); if(n != sizeof(req)){ if(n < 0) printk("io_thread - read failed, fd = %d, " "err = %d\n", kernel_fd, -n); else { printk("io_thread - short read, fd = %d, " "length = %d\n", kernel_fd, n); } continue; } io_count++; do_io(&req); n = os_write_file(kernel_fd, &req, sizeof(req)); if(n != sizeof(req)) printk("io_thread - write failed, fd = %d, err = %d\n", kernel_fd, -n); } return 0; }