X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fum%2Fdrivers%2Fubd_kern.c;h=49c047b75cc556cbda484a5c6166d23d5b137f7c;hb=refs%2Fheads%2Fvserver;hp=0c3890b3ea127163310ea654a48323951e941afe;hpb=5273a3df6485dc2ad6aa7ddd441b9a21970f003b;p=linux-2.6.git diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 0c3890b3e..49c047b75 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -1,4 +1,4 @@ -/* +/* * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) * Licensed under the GPL */ @@ -8,17 +8,22 @@ * 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" @@ -28,6 +33,7 @@ #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" @@ -40,38 +46,101 @@ #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 }; + +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; -static spinlock_t ubd_io_lock = SPIN_LOCK_UNLOCKED; -static spinlock_t ubd_lock = SPIN_LOCK_UNLOCKED; + 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); -static void (*do_ubd)(void); +/* 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 (8) +#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 = 0; +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 }) @@ -86,7 +155,9 @@ static struct gendisk *fake_gendisk[MAX_DEV]; 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; @@ -95,14 +166,18 @@ struct cow { }; struct ubd { + /* name (and fd, below) of the file opened for writing, either the + * backing or the cow file. */ char *file; - int is_dir; int count; int fd; __u64 size; struct openflags boot_openflags; struct openflags openflags; + unsigned shared:1; + unsigned no_cow:1; struct cow cow; + struct platform_device pdev; }; #define DEFAULT_COW { \ @@ -115,25 +190,17 @@ struct ubd { #define DEFAULT_UBD { \ .file = NULL, \ - .is_dir = 0, \ .count = 0, \ .fd = -1, \ .size = -1, \ .boot_openflags = OPEN_FLAGS, \ .openflags = OPEN_FLAGS, \ + .no_cow = 0, \ + .shared = 0, \ .cow = DEFAULT_COW, \ } -struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; - -static int ubd0_init(void) -{ - if(ubd_dev[0].file == NULL) - ubd_dev[0].file = "root_fs"; - return(0); -} - -__initcall(ubd0_init); +struct ubd ubd_devs[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; /* Only changed by fake_ide_setup which is a setup */ static int fake_ide = 0; @@ -142,7 +209,7 @@ static struct proc_dir_entry *proc_ide = NULL; static void make_proc_ide(void) { - proc_ide_root = proc_mkdir("ide", 0); + proc_ide_root = proc_mkdir("ide", NULL); proc_ide = proc_mkdir("ide0", proc_ide_root); } @@ -196,104 +263,147 @@ __uml_help(fake_ide_setup, " 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); +} + +/* If *index_out == -1 at exit, the passed option was a general one; + * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it + * should not be freed on exit. + */ 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; + int n, err, i; if(index_out) *index_out = -1; - n = *str++; + n = *str; if(n == '='){ - static int fake_major_allowed = 1; char *end; int major; + str++; if(!strcmp(str, "sync")){ - global_openflags.s = 1; + global_openflags = of_sync(global_openflags); return(0); } major = simple_strtoul(str, &end, 0); if((*end != '\0') || (end == str)){ - printk(KERN_ERR + printk(KERN_ERR "ubd_setup : didn't parse major number\n"); return(1); } - if(!fake_major_allowed){ - printk(KERN_ERR "Can't assign a fake major twice\n"); - return(1); - } - err = 1; - spin_lock(&ubd_lock); - if(!fake_major_allowed){ + 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; - fake_major_allowed = 0; printk(KERN_INFO "Setting extra ubd major number to %d\n", major); err = 0; out1: - spin_unlock(&ubd_lock); + mutex_unlock(&ubd_lock); return(err); } - if(n < '0'){ - printk(KERN_ERR "ubd_setup : index out of range\n"); } - - if((n >= '0') && (n <= '9')) n -= '0'; - else if((n >= 'a') && (n <= 'z')) n -= 'a'; - else { - printk(KERN_ERR "ubd_setup : device syntax invalid\n"); + n = parse_unit(&str); + if(n < 0){ + printk(KERN_ERR "ubd_setup : couldn't parse unit number " + "'%s'\n", str); return(1); } if(n >= MAX_DEV){ - printk(KERN_ERR "ubd_setup : index out of range " - "(%d devices)\n", MAX_DEV); + printk(KERN_ERR "ubd_setup : index %d out of range " + "(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1); return(1); } err = 1; - spin_lock(&ubd_lock); + mutex_lock(&ubd_lock); - if(ubd_dev[n].file != NULL){ + ubd_dev = &ubd_devs[n]; + if(ubd_dev->file != NULL){ printk(KERN_ERR "ubd_setup : device already configured\n"); - goto out2; + goto out; } - if(index_out) *index_out = n; - - if (*str == 'r'){ - flags.w = 0; - str++; - } - if (*str == 's'){ - flags.s = 1; + 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++ != '='){ + + if (*str == '=') + printk(KERN_ERR "ubd_setup : Too many flags specified\n"); + else printk(KERN_ERR "ubd_setup : Expected '='\n"); - goto out2; - } + goto out; +break_loop: err = 0; backing_file = strchr(str, ','); + + if (!backing_file) { + backing_file = strchr(str, ':'); + } + if(backing_file){ - *backing_file = '\0'; - backing_file++; - } - ubd_dev[n].file = str; - if(ubd_is_dir(ubd_dev[n].file)) - ubd_dev[n].is_dir = 1; - ubd_dev[n].cow.file = backing_file; - ubd_dev[n].boot_openflags = flags; - out2: - spin_unlock(&ubd_lock); + 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); } @@ -305,24 +415,47 @@ static int ubd_setup(char *str) __setup("ubd", ubd_setup); __uml_help(ubd_setup, -"ubd=\n" +"ubd=[(:|,)]\n" " This is used to associate a device with a file in the underlying\n" -" filesystem. Usually, there is a filesystem in the file, but \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" +" machine by running 'dd' on the device. 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' (has to be _after_ 'r', if there is one) will cause data\n" -" to be written to disk on the host immediately.\n\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"); + printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n"); fakehd_set = 1; return 1; } @@ -340,17 +473,17 @@ int thread_fd = -1; /* Changed by ubd_handler, which is serialized because interrupts only * happen on CPU 0. + * XXX: currently unused. */ -int intr_count = 0; +static int intr_count = 0; -static void ubd_finish(struct request *req, int error) +/* call ubd_finish if you need to serialize */ +static void __ubd_finish(struct request *req, int error) { int nsect; if(error){ - spin_lock(&ubd_io_lock); end_request(req, 0); - spin_unlock(&ubd_io_lock); return; } nsect = req->current_nr_sectors; @@ -359,41 +492,49 @@ static void ubd_finish(struct request *req, int error) req->errors = 0; req->nr_sectors -= nsect; req->current_nr_sectors = 0; - spin_lock(&ubd_io_lock); 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 = NULL; + do_ubd = 0; intr_count++; - n = read_ubd_fs(thread_fd, &req, sizeof(req)); + n = os_read_file(thread_fd, &req, sizeof(req)); if(n != sizeof(req)){ printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, " - "errno = %d\n", os_getpid(), -n); + "err = %d\n", os_getpid(), -n); spin_lock(&ubd_io_lock); end_request(rq, 0); spin_unlock(&ubd_io_lock); return; } - - if((req.offset != ((__u64) (rq->sector)) << 9) || - (req.length != (rq->current_nr_sectors) << 9)) - panic("I/O op mismatch"); - + 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 void ubd_intr(int irq, void *dev, struct pt_regs *unused) +static irqreturn_t ubd_intr(int irq, void *dev) { ubd_handler(); + return(IRQ_HANDLED); } /* Only changed by ubd_init, which is an initcall. */ @@ -401,99 +542,123 @@ static int io_pid = -1; void kill_io_thread(void) { - if(io_pid != -1) + 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) +static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) { char *file; - file = dev->cow.file ? dev->cow.file : dev->file; + file = ubd_dev->cow.file ? ubd_dev->cow.file : ubd_dev->file; return(os_file_size(file, size_out)); } -static void ubd_close(struct ubd *dev) +static void ubd_close_dev(struct ubd *ubd_dev) { - os_close_file(dev->fd); - if(dev->cow.file == NULL) + os_close_file(ubd_dev->fd); + if(ubd_dev->cow.file == NULL) return; - os_close_file(dev->cow.fd); - vfree(dev->cow.bitmap); - dev->cow.bitmap = NULL; + os_close_file(ubd_dev->cow.fd); + vfree(ubd_dev->cow.bitmap); + ubd_dev->cow.bitmap = NULL; } -static int ubd_open_dev(struct ubd *dev) +static int ubd_open_dev(struct ubd *ubd_dev) { struct openflags flags; - int err, n, create_cow, *create_ptr; + char **back_ptr; + int err, create_cow, *create_ptr; + int fd; + ubd_dev->openflags = ubd_dev->boot_openflags; create_cow = 0; - create_ptr = (dev->cow.file != NULL) ? &create_cow : NULL; - dev->fd = open_ubd_file(dev->file, &dev->openflags, &dev->cow.file, - &dev->cow.bitmap_offset, &dev->cow.bitmap_len, - &dev->cow.data_offset, create_ptr); - - if((dev->fd == -ENOENT) && create_cow){ - n = dev - ubd_dev; - dev->fd = create_cow_file(dev->file, dev->cow.file, - dev->openflags, 1 << 9, - &dev->cow.bitmap_offset, - &dev->cow.bitmap_len, - &dev->cow.data_offset); - if(dev->fd >= 0){ + create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; + back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; + + 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((fd == -ENOENT) && create_cow){ + 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(fd >= 0){ printk(KERN_INFO "Creating \"%s\" as COW file for " - "\"%s\"\n", dev->file, dev->cow.file); + "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); } } - if(dev->fd < 0) return(dev->fd); + if(fd < 0){ + printk("Failed to open '%s', errno = %d\n", ubd_dev->file, + -fd); + return fd; + } + ubd_dev->fd = fd; - if(dev->cow.file != NULL){ + if(ubd_dev->cow.file != NULL){ err = -ENOMEM; - dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len); - if(dev->cow.bitmap == NULL) goto error; + 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(dev->fd, dev->cow.bitmap, - dev->cow.bitmap_offset, - dev->cow.bitmap_len); - if(err) goto error; + 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 = dev->openflags; + flags = ubd_dev->openflags; flags.w = 0; - err = open_ubd_file(dev->cow.file, &flags, NULL, NULL, NULL, - NULL, NULL); + err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, + NULL, NULL, NULL, NULL); if(err < 0) goto error; - dev->cow.fd = err; + ubd_dev->cow.fd = err; } return(0); error: - os_close_file(dev->fd); + os_close_file(ubd_dev->fd); return(err); } -static int ubd_new_disk(int major, u64 size, int unit, +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) - return -ENOMEM; + if(disk == NULL) + return(-ENOMEM); disk->major = major; disk->first_minor = unit << UBD_SHIFT; disk->fops = &ubd_blops; set_capacity(disk, size / 512); - sprintf(disk->disk_name, "ubd"); - sprintf(disk->devfs_name, "ubd/disc%d", unit); + if(major == MAJOR_NR) + sprintf(disk->disk_name, "ubd%c", 'a' + unit); + 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_dev[unit]; + disk->private_data = &ubd_devs[unit]; disk->queue = ubd_queue; add_disk(disk); @@ -501,30 +666,29 @@ static int ubd_new_disk(int major, u64 size, int unit, return 0; } +#define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9)) + static int ubd_add(int n) { - struct ubd *dev = &ubd_dev[n]; + struct ubd *ubd_dev = &ubd_devs[n]; int err; - if(dev->is_dir) - return(-EISDIR); + err = -ENODEV; + if(ubd_dev->file == NULL) + goto out; - if (!dev->file) - return(-ENODEV); + err = ubd_file_size(ubd_dev, &ubd_dev->size); + if(err < 0) + goto out; - if (ubd_open_dev(dev)) - return(-ENODEV); + ubd_dev->size = ROUND_BLOCK(ubd_dev->size); - err = ubd_file_size(dev, &dev->size); + err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]); if(err) - return(err); + goto out; - err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]); - if(err) - return(err); - - if(fake_major) - ubd_new_disk(fake_major, dev->size, n, + 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 */ @@ -532,95 +696,107 @@ static int ubd_add(int n) if (fake_ide) make_ide_entries(ubd_gendisk[n]->disk_name); - ubd_close(dev); - return 0; + err = 0; +out: + return err; } static int ubd_config(char *str) { - int n, err; + int n, ret; - str = uml_strdup(str); - if(str == NULL){ + str = kstrdup(str, GFP_KERNEL); + if (str == NULL) { printk(KERN_ERR "ubd_config failed to strdup string\n"); - return(1); + ret = 1; + goto out; } - err = ubd_setup_common(str, &n); - if(err){ - kfree(str); - return(-1); + ret = ubd_setup_common(str, &n); + if (ret) { + ret = -1; + goto err_free; + } + if (n == -1) { + ret = 0; + goto err_free; } - if(n == -1) return(0); - spin_lock(&ubd_lock); - err = ubd_add(n); - if(err) - ubd_dev[n].file = NULL; - spin_unlock(&ubd_lock); + mutex_lock(&ubd_lock); + ret = ubd_add(n); + if (ret) + ubd_devs[n].file = NULL; + mutex_unlock(&ubd_lock); - return(err); +out: + return ret; + +err_free: + kfree(str); + goto out; } -static int ubd_get_config(char *dev, char *str, int size, char **error_out) +static int ubd_get_config(char *name, char *str, int size, char **error_out) { - struct ubd *ubd; - char *end; - int major, n = 0; + struct ubd *ubd_dev; + int n, len = 0; - major = simple_strtoul(dev, &end, 0); - if((*end != '\0') || (end == dev)){ - *error_out = "ubd_get_config : didn't parse major number"; + n = parse_unit(&name); + if((n >= MAX_DEV) || (n < 0)){ + *error_out = "ubd_get_config : device number out of range"; return(-1); } - if((major >= MAX_DEV) || (major < 0)){ - *error_out = "ubd_get_config : major number out of range"; - return(-1); - } + ubd_dev = &ubd_devs[n]; + mutex_lock(&ubd_lock); - ubd = &ubd_dev[major]; - spin_lock(&ubd_lock); - - if(ubd->file == NULL){ - CONFIG_CHUNK(str, size, n, "", 1); + if(ubd_dev->file == NULL){ + CONFIG_CHUNK(str, size, len, "", 1); goto out; } - CONFIG_CHUNK(str, size, n, ubd->file, 0); + CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); - if(ubd->cow.file != NULL){ - CONFIG_CHUNK(str, size, n, ",", 0); - CONFIG_CHUNK(str, size, n, ubd->cow.file, 1); + 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, n, "", 1); + else CONFIG_CHUNK(str, size, len, "", 1); out: - spin_unlock(&ubd_lock); - return(n); + mutex_unlock(&ubd_lock); + return(len); } -static int ubd_remove(char *str) +static int ubd_id(char **str, int *start_out, int *end_out) { - struct ubd *dev; - int n, err = -ENODEV; + int n; - if(!isdigit(*str)) - return(err); /* it should be a number 0-7/a-h */ - - n = *str - '0'; - if(n >= MAX_DEV) - return(err); + n = parse_unit(str); + *start_out = 0; + *end_out = MAX_DEV - 1; + return n; +} - dev = &ubd_dev[n]; - if(dev->count > 0) - return(-EBUSY); /* you cannot remove a open disk */ +static int ubd_remove(int n) +{ + struct ubd *ubd_dev; + int err = -ENODEV; - err = 0; - spin_lock(&ubd_lock); + 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; @@ -631,21 +807,24 @@ static int ubd_remove(char *str) fake_gendisk[n] = NULL; } - *dev = ((struct ubd) DEFAULT_UBD); + platform_device_unregister(&ubd_dev->pdev); + *ubd_dev = ((struct ubd) DEFAULT_UBD); err = 0; - out: - spin_unlock(&ubd_lock); - return(err); +out: + mutex_unlock(&ubd_lock); + return err; } +/* All these are called by mconsole in process context and without ubd-specific locks. */ 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) +static int __init ubd_mc_init(void) { mconsole_register_dev(&ubd_mc); return 0; @@ -653,11 +832,27 @@ static int ubd_mc_init(void) __initcall(ubd_mc_init); -int ubd_init(void) +static int __init 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); + +static struct platform_driver ubd_driver = { + .driver = { + .name = DRIVER_NAME, + }, +}; + +static int __init ubd_init(void) { int i; - devfs_mk_dir("ubd"); if (register_blkdev(MAJOR_NR, "ubd")) return -1; @@ -667,45 +862,46 @@ int ubd_init(void) return -1; } - elevator_init(ubd_queue, &elevator_noop); - - if (fake_major != 0) { + if (fake_major != MAJOR_NR) { char name[sizeof("ubd_nnn\0")]; snprintf(name, sizeof(name), "ubd_%d", fake_major); - devfs_mk_dir(name); if (register_blkdev(fake_major, "ubd")) return -1; } - for (i = 0; i < MAX_DEV; i++) + 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){ +static int __init 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"); - return(0); + printk(KERN_INFO "ubd: Synchronous mode\n"); + /* Letting ubd=sync be like using ubd#s= instead of ubd#= is + * enough. So use anyway the io thread. */ } stack = alloc_stack(0, 0); - io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), + io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), &thread_fd); if(io_pid < 0){ - printk(KERN_ERR + 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); + 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); @@ -713,28 +909,26 @@ 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 = -EISDIR; - - if(dev->is_dir == 1) - goto out; + struct ubd *ubd_dev = disk->private_data; + int err = 0; - err = 0; - if(dev->count == 0){ - dev->openflags = dev->boot_openflags; - - err = ubd_open_dev(dev); + 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, dev->file, -err); + disk->disk_name, ubd_dev->file, -err); goto out; } } - dev->count++; - if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){ - if(--dev->count == 0) ubd_close(dev); + 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); } @@ -742,98 +936,114 @@ static int ubd_open(struct inode *inode, struct file *filp) static int ubd_release(struct inode * inode, struct file * file) { struct gendisk *disk = inode->i_bdev->bd_disk; - struct ubd *dev = disk->private_data; + struct ubd *ubd_dev = disk->private_data; - if(--dev->count == 0) - ubd_close(dev); + if(--ubd_dev->count == 0) + ubd_close_dev(ubd_dev); return(0); } -void cowify_req(struct io_thread_req *req, struct ubd *dev) +static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, + __u64 *cow_offset, unsigned long *bitmap, + __u64 bitmap_offset, unsigned long *bitmap_words, + __u64 bitmap_len) +{ + __u64 sector = io_offset >> 9; + int i, update_bitmap = 0; + + for(i = 0; i < length >> 9; i++){ + if(cow_mask != NULL) + ubd_set_bit(i, (unsigned char *) cow_mask); + if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) + continue; + + update_bitmap = 1; + ubd_set_bit(sector + i, (unsigned char *) bitmap); + } + + if(!update_bitmap) + return; + + *cow_offset = sector / (sizeof(unsigned long) * 8); + + /* This takes care of the case where we're exactly at the end of the + * device, and *cow_offset + 1 is off the end. So, just back it up + * by one word. Thanks to Lynn Kerby for the fix and James McMechan + * for the original diagnosis. + */ + if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) / + sizeof(unsigned long) - 1)) + (*cow_offset)--; + + bitmap_words[0] = bitmap[*cow_offset]; + bitmap_words[1] = bitmap[*cow_offset + 1]; + + *cow_offset *= sizeof(unsigned long); + *cow_offset += bitmap_offset; +} + +static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, + __u64 bitmap_offset, __u64 bitmap_len) { - int i, update_bitmap, sector = req->offset >> 9; + __u64 sector = req->offset >> 9; + int i; if(req->length > (sizeof(req->sector_mask) * 8) << 9) panic("Operation too long"); + if(req->op == UBD_READ) { for(i = 0; i < req->length >> 9; i++){ - if(ubd_test_bit(sector + i, (unsigned char *) - dev->cow.bitmap)){ - ubd_set_bit(i, (unsigned char *) + if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) + ubd_set_bit(i, (unsigned char *) &req->sector_mask); - } } - } - else { - update_bitmap = 0; - for(i = 0; i < req->length >> 9; i++){ - ubd_set_bit(i, (unsigned char *) - &req->sector_mask); - if(!ubd_test_bit(sector + i, (unsigned char *) - dev->cow.bitmap)) - update_bitmap = 1; - ubd_set_bit(sector + i, (unsigned char *) - dev->cow.bitmap); - } - if(update_bitmap){ - req->cow_offset = sector / (sizeof(unsigned long) * 8); - req->bitmap_words[0] = - dev->cow.bitmap[req->cow_offset]; - req->bitmap_words[1] = - dev->cow.bitmap[req->cow_offset + 1]; - req->cow_offset *= sizeof(unsigned long); - req->cow_offset += dev->cow.bitmap_offset; - } } + else cowify_bitmap(req->offset, req->length, &req->sector_mask, + &req->cow_offset, bitmap, bitmap_offset, + req->bitmap_words, bitmap_len); } +/* Called with ubd_io_lock held */ static int prepare_request(struct request *req, struct io_thread_req *io_req) { struct gendisk *disk = req->rq_disk; - struct ubd *dev = disk->private_data; - __u64 block; - int nsect; - - if(req->rq_status == RQ_INACTIVE) return(1); - - if(dev->is_dir){ - strcpy(req->buffer, "HOSTFS:"); - strcat(req->buffer, dev->file); - spin_lock(&ubd_io_lock); - end_request(req, 1); - spin_unlock(&ubd_io_lock); - return(1); - } + struct ubd *ubd_dev = disk->private_data; + __u64 offset; + int len; - if((rq_data_dir(req) == WRITE) && !dev->openflags.w){ - printk("Write attempted on readonly ubd device %s\n", + /* 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); - spin_lock(&ubd_io_lock); end_request(req, 0); - spin_unlock(&ubd_io_lock); return(1); } - block = req->sector; - nsect = req->current_nr_sectors; + offset = ((__u64) req->sector) << 9; + len = req->current_nr_sectors << 9; + + io_req->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->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd; - io_req->fds[1] = dev->fd; + io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; io_req->offsets[0] = 0; - io_req->offsets[1] = dev->cow.data_offset; - io_req->offset = ((__u64) block) << 9; - io_req->length = nsect << 9; + io_req->offsets[1] = ubd_dev->cow.data_offset; io_req->buffer = req->buffer; io_req->sectorsize = 1 << 9; - io_req->sector_mask = 0; - io_req->cow_offset = -1; - io_req->error = 0; - if(dev->cow.file != NULL) cowify_req(io_req, dev); + if(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; @@ -841,22 +1051,21 @@ static void do_ubd_request(request_queue_t *q) int err, n; if(thread_fd == -1){ - while(!list_empty(&q->queue_head)){ - req = elv_next_request(q); + while((req = elv_next_request(q)) != NULL){ err = prepare_request(req, &io_req); if(!err){ do_io(&io_req); - ubd_finish(req, io_req.error); + __ubd_finish(req, io_req.error); } } } else { - if(do_ubd || list_empty(&q->queue_head)) return; - req = elv_next_request(q); + if(do_ubd || (req = elv_next_request(q)) == NULL) + return; err = prepare_request(req, &io_req); if(!err){ - do_ubd = ubd_handler; - n = write_ubd_fs(thread_fd, (char *) &io_req, + 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, " @@ -865,12 +1074,20 @@ static void do_ubd_request(request_queue_t *q) } } +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 hd_geometry *loc = (struct hd_geometry *) arg; - struct ubd *dev = inode->i_bdev->bd_disk->private_data; - int err; + struct ubd *ubd_dev = inode->i_bdev->bd_disk->private_data; struct hd_driveid ubd_id = { .cyls = 0, .heads = 128, @@ -878,70 +1095,323 @@ static int ubd_ioctl(struct inode * inode, struct file * file, }; 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 = 2; - return(copy_to_user(loc, &g, sizeof(g)) ? -EFAULT : 0); - - case HDIO_SET_UNMASKINTR: - if(!capable(CAP_SYS_ADMIN)) return(-EACCES); - if((arg > 1) || (inode->i_bdev->bd_contains != inode->i_bdev)) - return(-EINVAL); - return(0); - - case HDIO_GET_UNMASKINTR: - if(!arg) return(-EINVAL); - err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long)); - if(err) - return(err); - return(0); - - case HDIO_GET_MULTCOUNT: - if(!arg) return(-EINVAL); - err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long)); - if(err) - return(err); - return(0); - - case HDIO_SET_MULTCOUNT: - if(!capable(CAP_SYS_ADMIN)) return(-EACCES); - if(inode->i_bdev->bd_contains != inode->i_bdev) - return(-EINVAL); - return(0); - case HDIO_GET_IDENTITY: - ubd_id.cyls = dev->size / (128 * 32 * 512); - if(copy_to_user((char *) arg, (char *) &ubd_id, + 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 *) arg, sizeof(volume))) + 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 *) arg, &volume, sizeof(volume))) + if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) return(-EFAULT); return(0); } return(-EINVAL); } -/* - * 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: +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. XXX: currently unused. */ +static 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; +}