diff options
Diffstat (limited to 'arch/um/drivers/ubd_kern.c')
| -rw-r--r-- | arch/um/drivers/ubd_kern.c | 1669 |
1 files changed, 1669 insertions, 0 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c new file mode 100644 index 00000000000..4d8b165bfa4 --- /dev/null +++ b/arch/um/drivers/ubd_kern.c @@ -0,0 +1,1669 @@ +/* + * 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/config.h" +#include "linux/module.h" +#include "linux/blkdev.h" +#include "linux/hdreg.h" +#include "linux/init.h" +#include "linux/devfs_fs_kernel.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 "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 "2_5compat.h" +#include "os.h" +#include "mem.h" +#include "mem_kern.h" +#include "cow.h" + +enum ubd_req { UBD_READ, UBD_WRITE, UBD_MMAP }; + +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 map_fd; + unsigned long long map_offset; + int error; +}; + +extern 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); +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" + +static DEFINE_SPINLOCK(ubd_io_lock); +static DEFINE_SPINLOCK(ubd_lock); + +static void (*do_ubd)(void); + +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); + +#define MAX_DEV (8) + +/* Changed in early boot */ +static int ubd_do_mmap = 0; +#define UBD_MMAP_BLOCK_SIZE PAGE_SIZE + +static struct block_device_operations ubd_blops = { + .owner = THIS_MODULE, + .open = ubd_open, + .release = ubd_release, + .ioctl = ubd_ioctl, +}; + +/* 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 { + char *file; + int fd; + unsigned long *bitmap; + unsigned long bitmap_len; + int bitmap_offset; + int data_offset; +}; + +struct ubd { + char *file; + int count; + int fd; + __u64 size; + struct openflags boot_openflags; + struct openflags openflags; + int no_cow; + struct cow cow; + struct platform_device pdev; + + int map_writes; + int map_reads; + int nomap_writes; + int nomap_reads; + int write_maps; +}; + +#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, \ + .cow = DEFAULT_COW, \ + .map_writes = 0, \ + .map_reads = 0, \ + .nomap_writes = 0, \ + .nomap_reads = 0, \ + .write_maps = 0, \ +} + +struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; + +static int ubd0_init(void) +{ + struct ubd *dev = &ubd_dev[0]; + + if(dev->file == NULL) + 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 <= 'h')) { + n = *str - 'a'; + str++; + *ptr = str; + } + return(n); +} + +static int ubd_setup_common(char *str, int *index_out) +{ + struct ubd *dev; + struct openflags flags = global_openflags; + char *backing_file; + int n, err, i; + + if(index_out) *index_out = -1; + n = *str; + if(n == '='){ + char *end; + int major; + + str++; + if(!strcmp(str, "mmap")){ + CHOOSE_MODE(printk("mmap not supported by the ubd " + "driver in tt mode\n"), + ubd_do_mmap = 1); + return(0); + } + + if(!strcmp(str, "sync")){ + global_openflags = 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; + spin_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: + spin_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; + spin_lock(&ubd_lock); + + dev = &ubd_dev[n]; + if(dev->file != NULL){ + printk(KERN_ERR "ubd_setup : device already configured\n"); + goto out; + } + + if (index_out) + *index_out = n; + + for (i = 0; i < 4; i++) { + switch (*str) { + case 'r': + flags.w = 0; + break; + case 's': + flags.s = 1; + break; + case 'd': + dev->no_cow = 1; + break; + case '=': + str++; + goto break_loop; + default: + printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r,s 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(dev->no_cow) + printk(KERN_ERR "Can't specify both 'd' and a " + "cow file\n"); + else { + *backing_file = '\0'; + backing_file++; + } + } + dev->file = str; + dev->cow.file = backing_file; + dev->boot_openflags = flags; +out: + spin_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\n" +" to impossible to catch visually unless you specifically look for\n\n" +" them. The only result of any option starting with 'udb' is an error\n\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); +} + +static inline void ubd_finish(struct request *req, int error) +{ + spin_lock(&ubd_io_lock); + __ubd_finish(req, error); + spin_unlock(&ubd_io_lock); +} + +/* Called without ubd_io_lock held */ +static void ubd_handler(void) +{ + struct io_thread_req req; + struct request *rq = elv_next_request(ubd_queue); + int n, err; + + do_ubd = NULL; + 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; + } + + 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: + */ |