2 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
6 /* 2001-09-28...2002-04-17
7 * Partition stuff by James_McMechan@hotmail.com
8 * old style ubd by setting UBD_SHIFT to 0
9 * 2002-09-27...2002-10-18 massive tinkering for 2.5
10 * partitions have changed in 2.5
11 * 2003-01-29 more tinkering for 2.5.59-1
12 * This should now address the sysfs problems and has
13 * the symlink for devfs to allow for booting with
14 * the common /dev/ubd/discX/... names rather than
15 * only /dev/ubdN/discN this version also has lots of
16 * clean ups preparing for ubd-many.
20 #define MAJOR_NR UBD_MAJOR
23 #include "linux/module.h"
24 #include "linux/blkdev.h"
25 #include "linux/hdreg.h"
26 #include "linux/init.h"
27 #include "linux/cdrom.h"
28 #include "linux/proc_fs.h"
29 #include "linux/ctype.h"
30 #include "linux/capability.h"
32 #include "linux/vmalloc.h"
33 #include "linux/blkpg.h"
34 #include "linux/genhd.h"
35 #include "linux/spinlock.h"
36 #include "linux/platform_device.h"
37 #include "asm/segment.h"
38 #include "asm/uaccess.h"
40 #include "asm/types.h"
41 #include "asm/tlbflush.h"
42 #include "user_util.h"
44 #include "kern_util.h"
46 #include "mconsole_kern.h"
56 enum ubd_req
{ UBD_READ
, UBD_WRITE
};
58 struct io_thread_req
{
61 unsigned long offsets
[2];
62 unsigned long long offset
;
66 unsigned long sector_mask
;
67 unsigned long long cow_offset
;
68 unsigned long bitmap_words
[2];
72 extern int open_ubd_file(char *file
, struct openflags
*openflags
, int shared
,
73 char **backing_file_out
, int *bitmap_offset_out
,
74 unsigned long *bitmap_len_out
, int *data_offset_out
,
76 extern int create_cow_file(char *cow_file
, char *backing_file
,
77 struct openflags flags
, int sectorsize
,
78 int alignment
, int *bitmap_offset_out
,
79 unsigned long *bitmap_len_out
,
80 int *data_offset_out
);
81 extern int read_cow_bitmap(int fd
, void *buf
, int offset
, int len
);
82 extern void do_io(struct io_thread_req
*req
);
84 static inline int ubd_test_bit(__u64 bit
, unsigned char *data
)
89 bits
= sizeof(data
[0]) * 8;
92 return((data
[n
] & (1 << off
)) != 0);
95 static inline void ubd_set_bit(__u64 bit
, unsigned char *data
)
100 bits
= sizeof(data
[0]) * 8;
103 data
[n
] |= (1 << off
);
105 /*End stuff from ubd_user.h*/
107 #define DRIVER_NAME "uml-blkdev"
109 static DEFINE_SPINLOCK(ubd_io_lock
);
110 static DEFINE_SPINLOCK(ubd_lock
);
112 static void (*do_ubd
)(void);
114 static int ubd_open(struct inode
* inode
, struct file
* filp
);
115 static int ubd_release(struct inode
* inode
, struct file
* file
);
116 static int ubd_ioctl(struct inode
* inode
, struct file
* file
,
117 unsigned int cmd
, unsigned long arg
);
118 static int ubd_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
);
122 static struct block_device_operations ubd_blops
= {
123 .owner
= THIS_MODULE
,
125 .release
= ubd_release
,
127 .getgeo
= ubd_getgeo
,
130 /* Protected by the queue_lock */
131 static request_queue_t
*ubd_queue
;
133 /* Protected by ubd_lock */
134 static int fake_major
= MAJOR_NR
;
136 static struct gendisk
*ubd_gendisk
[MAX_DEV
];
137 static struct gendisk
*fake_gendisk
[MAX_DEV
];
139 #ifdef CONFIG_BLK_DEV_UBD_SYNC
140 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
143 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
147 /* Not protected - changed only in ubd_setup_common and then only to
150 static struct openflags global_openflags
= OPEN_FLAGS
;
153 /* This is the backing file, actually */
156 unsigned long *bitmap
;
157 unsigned long bitmap_len
;
167 struct openflags boot_openflags
;
168 struct openflags openflags
;
172 struct platform_device pdev
;
175 #define DEFAULT_COW { \
179 .bitmap_offset = 0, \
183 #define DEFAULT_UBD { \
188 .boot_openflags = OPEN_FLAGS, \
189 .openflags = OPEN_FLAGS, \
192 .cow = DEFAULT_COW, \
195 struct ubd ubd_dev
[MAX_DEV
] = { [ 0 ... MAX_DEV
- 1 ] = DEFAULT_UBD
};
197 static int ubd0_init(void)
199 struct ubd
*dev
= &ubd_dev
[0];
201 if(dev
->file
== NULL
)
202 dev
->file
= "root_fs";
206 __initcall(ubd0_init
);
208 /* Only changed by fake_ide_setup which is a setup */
209 static int fake_ide
= 0;
210 static struct proc_dir_entry
*proc_ide_root
= NULL
;
211 static struct proc_dir_entry
*proc_ide
= NULL
;
213 static void make_proc_ide(void)
215 proc_ide_root
= proc_mkdir("ide", NULL
);
216 proc_ide
= proc_mkdir("ide0", proc_ide_root
);
219 static int proc_ide_read_media(char *page
, char **start
, off_t off
, int count
,
220 int *eof
, void *data
)
224 strcpy(page
, "disk\n");
225 len
= strlen("disk\n");
229 if (len
<= 0) return 0;
236 static void make_ide_entries(char *dev_name
)
238 struct proc_dir_entry
*dir
, *ent
;
241 if(proc_ide_root
== NULL
) make_proc_ide();
243 dir
= proc_mkdir(dev_name
, proc_ide
);
246 ent
= create_proc_entry("media", S_IFREG
|S_IRUGO
, dir
);
250 ent
->read_proc
= proc_ide_read_media
;
251 ent
->write_proc
= NULL
;
252 sprintf(name
,"ide0/%s", dev_name
);
253 proc_symlink(dev_name
, proc_ide_root
, name
);
256 static int fake_ide_setup(char *str
)
262 __setup("fake_ide", fake_ide_setup
);
264 __uml_help(fake_ide_setup
,
266 " Create ide0 entries that map onto ubd devices.\n\n"
269 static int parse_unit(char **ptr
)
271 char *str
= *ptr
, *end
;
275 n
= simple_strtoul(str
, &end
, 0);
280 else if (('a' <= *str
) && (*str
<= 'h')) {
288 static int ubd_setup_common(char *str
, int *index_out
)
291 struct openflags flags
= global_openflags
;
295 if(index_out
) *index_out
= -1;
302 if(!strcmp(str
, "sync")){
303 global_openflags
= of_sync(global_openflags
);
306 major
= simple_strtoul(str
, &end
, 0);
307 if((*end
!= '\0') || (end
== str
)){
309 "ubd_setup : didn't parse major number\n");
314 spin_lock(&ubd_lock
);
315 if(fake_major
!= MAJOR_NR
){
316 printk(KERN_ERR
"Can't assign a fake major twice\n");
322 printk(KERN_INFO
"Setting extra ubd major number to %d\n",
326 spin_unlock(&ubd_lock
);
330 n
= parse_unit(&str
);
332 printk(KERN_ERR
"ubd_setup : couldn't parse unit number "
337 printk(KERN_ERR
"ubd_setup : index %d out of range "
338 "(%d devices, from 0 to %d)\n", n
, MAX_DEV
, MAX_DEV
- 1);
343 spin_lock(&ubd_lock
);
346 if(dev
->file
!= NULL
){
347 printk(KERN_ERR
"ubd_setup : device already configured\n");
354 for (i
= 0; i
< sizeof("rscd="); i
++) {
372 printk(KERN_ERR
"ubd_setup : Expected '=' or flag letter (r, s, c, or d)\n");
379 printk(KERN_ERR
"ubd_setup : Too many flags specified\n");
381 printk(KERN_ERR
"ubd_setup : Expected '='\n");
386 backing_file
= strchr(str
, ',');
389 backing_file
= strchr(str
, ':');
394 printk(KERN_ERR
"Can't specify both 'd' and a "
397 *backing_file
= '\0';
402 dev
->cow
.file
= backing_file
;
403 dev
->boot_openflags
= flags
;
405 spin_unlock(&ubd_lock
);
409 static int ubd_setup(char *str
)
411 ubd_setup_common(str
, NULL
);
415 __setup("ubd", ubd_setup
);
416 __uml_help(ubd_setup
,
417 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
418 " This is used to associate a device with a file in the underlying\n"
419 " filesystem. When specifying two filenames, the first one is the\n"
420 " COW name and the second is the backing file name. As separator you can\n"
421 " use either a ':' or a ',': the first one allows writing things like;\n"
422 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
423 " while with a ',' the shell would not expand the 2nd '~'.\n"
424 " When using only one filename, UML will detect whether to thread it like\n"
425 " a COW file or a backing file. To override this detection, add the 'd'\n"
427 " ubd0d=BackingFile\n"
428 " Usually, there is a filesystem in the file, but \n"
429 " that's not required. Swap devices containing swap files can be\n"
430 " specified like this. Also, a file which doesn't contain a\n"
431 " filesystem can have its contents read in the virtual \n"
432 " machine by running 'dd' on the device. <n> must be in the range\n"
433 " 0 to 7. Appending an 'r' to the number will cause that device\n"
434 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
435 " an 's' will cause data to be written to disk on the host immediately.\n\n"
438 static int udb_setup(char *str
)
440 printk("udb%s specified on command line is almost certainly a ubd -> "
445 __setup("udb", udb_setup
);
446 __uml_help(udb_setup
,
448 " This option is here solely to catch ubd -> udb typos, which can be\n"
449 " to impossible to catch visually unless you specifically look for\n"
450 " them. The only result of any option starting with 'udb' is an error\n"
451 " in the boot output.\n\n"
454 static int fakehd_set
= 0;
455 static int fakehd(char *str
)
457 printk(KERN_INFO
"fakehd : Changing ubd name to \"hd\".\n");
462 __setup("fakehd", fakehd
);
465 " Change the ubd device name to \"hd\".\n\n"
468 static void do_ubd_request(request_queue_t
* q
);
470 /* Only changed by ubd_init, which is an initcall. */
473 /* Changed by ubd_handler, which is serialized because interrupts only
478 /* call ubd_finish if you need to serialize */
479 static void __ubd_finish(struct request
*req
, int error
)
487 nsect
= req
->current_nr_sectors
;
488 req
->sector
+= nsect
;
489 req
->buffer
+= nsect
<< 9;
491 req
->nr_sectors
-= nsect
;
492 req
->current_nr_sectors
= 0;
496 static inline void ubd_finish(struct request
*req
, int error
)
498 spin_lock(&ubd_io_lock
);
499 __ubd_finish(req
, error
);
500 spin_unlock(&ubd_io_lock
);
503 /* Called without ubd_io_lock held */
504 static void ubd_handler(void)
506 struct io_thread_req req
;
507 struct request
*rq
= elv_next_request(ubd_queue
);
512 n
= os_read_file(thread_fd
, &req
, sizeof(req
));
513 if(n
!= sizeof(req
)){
514 printk(KERN_ERR
"Pid %d - spurious interrupt in ubd_handler, "
515 "err = %d\n", os_getpid(), -n
);
516 spin_lock(&ubd_io_lock
);
518 spin_unlock(&ubd_io_lock
);
522 ubd_finish(rq
, req
.error
);
523 reactivate_fd(thread_fd
, UBD_IRQ
);
524 do_ubd_request(ubd_queue
);
527 static irqreturn_t
ubd_intr(int irq
, void *dev
, struct pt_regs
*unused
)
533 /* Only changed by ubd_init, which is an initcall. */
534 static int io_pid
= -1;
536 void kill_io_thread(void)
539 os_kill_process(io_pid
, 1);
542 __uml_exitcall(kill_io_thread
);
544 static int ubd_file_size(struct ubd
*dev
, __u64
*size_out
)
548 file
= dev
->cow
.file
? dev
->cow
.file
: dev
->file
;
549 return(os_file_size(file
, size_out
));
552 static void ubd_close(struct ubd
*dev
)
554 os_close_file(dev
->fd
);
555 if(dev
->cow
.file
== NULL
)
558 os_close_file(dev
->cow
.fd
);
559 vfree(dev
->cow
.bitmap
);
560 dev
->cow
.bitmap
= NULL
;
563 static int ubd_open_dev(struct ubd
*dev
)
565 struct openflags flags
;
567 int err
, create_cow
, *create_ptr
;
569 dev
->openflags
= dev
->boot_openflags
;
571 create_ptr
= (dev
->cow
.file
!= NULL
) ? &create_cow
: NULL
;
572 back_ptr
= dev
->no_cow
? NULL
: &dev
->cow
.file
;
573 dev
->fd
= open_ubd_file(dev
->file
, &dev
->openflags
, dev
->shared
,
574 back_ptr
, &dev
->cow
.bitmap_offset
,
575 &dev
->cow
.bitmap_len
, &dev
->cow
.data_offset
,
578 if((dev
->fd
== -ENOENT
) && create_cow
){
579 dev
->fd
= create_cow_file(dev
->file
, dev
->cow
.file
,
580 dev
->openflags
, 1 << 9, PAGE_SIZE
,
581 &dev
->cow
.bitmap_offset
,
582 &dev
->cow
.bitmap_len
,
583 &dev
->cow
.data_offset
);
585 printk(KERN_INFO
"Creating \"%s\" as COW file for "
586 "\"%s\"\n", dev
->file
, dev
->cow
.file
);
591 printk("Failed to open '%s', errno = %d\n", dev
->file
,
596 if(dev
->cow
.file
!= NULL
){
598 dev
->cow
.bitmap
= (void *) vmalloc(dev
->cow
.bitmap_len
);
599 if(dev
->cow
.bitmap
== NULL
){
600 printk(KERN_ERR
"Failed to vmalloc COW bitmap\n");
603 flush_tlb_kernel_vm();
605 err
= read_cow_bitmap(dev
->fd
, dev
->cow
.bitmap
,
606 dev
->cow
.bitmap_offset
,
607 dev
->cow
.bitmap_len
);
611 flags
= dev
->openflags
;
613 err
= open_ubd_file(dev
->cow
.file
, &flags
, dev
->shared
, NULL
,
614 NULL
, NULL
, NULL
, NULL
);
615 if(err
< 0) goto error
;
620 os_close_file(dev
->fd
);
624 static int ubd_new_disk(int major
, u64 size
, int unit
,
625 struct gendisk
**disk_out
)
628 struct gendisk
*disk
;
630 disk
= alloc_disk(1 << UBD_SHIFT
);
635 disk
->first_minor
= unit
<< UBD_SHIFT
;
636 disk
->fops
= &ubd_blops
;
637 set_capacity(disk
, size
/ 512);
638 if(major
== MAJOR_NR
)
639 sprintf(disk
->disk_name
, "ubd%c", 'a' + unit
);
641 sprintf(disk
->disk_name
, "ubd_fake%d", unit
);
643 /* sysfs register (not for ide fake devices) */
644 if (major
== MAJOR_NR
) {
645 ubd_dev
[unit
].pdev
.id
= unit
;
646 ubd_dev
[unit
].pdev
.name
= DRIVER_NAME
;
647 platform_device_register(&ubd_dev
[unit
].pdev
);
648 disk
->driverfs_dev
= &ubd_dev
[unit
].pdev
.dev
;
651 disk
->private_data
= &ubd_dev
[unit
];
652 disk
->queue
= ubd_queue
;
659 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9))
661 static int ubd_add(int n
)
663 struct ubd
*dev
= &ubd_dev
[n
];
667 if(dev
->file
== NULL
)
670 err
= ubd_file_size(dev
, &dev
->size
);
674 dev
->size
= ROUND_BLOCK(dev
->size
);
676 err
= ubd_new_disk(MAJOR_NR
, dev
->size
, n
, &ubd_gendisk
[n
]);
680 if(fake_major
!= MAJOR_NR
)
681 ubd_new_disk(fake_major
, dev
->size
, n
,
684 /* perhaps this should also be under the "if (fake_major)" above */
685 /* using the fake_disk->disk_name and also the fakehd_set name */
687 make_ide_entries(ubd_gendisk
[n
]->disk_name
);
694 static int ubd_config(char *str
)
698 str
= kstrdup(str
, GFP_KERNEL
);
700 printk(KERN_ERR
"ubd_config failed to strdup string\n");
703 err
= ubd_setup_common(str
, &n
);
708 if(n
== -1) return(0);
710 spin_lock(&ubd_lock
);
713 ubd_dev
[n
].file
= NULL
;
714 spin_unlock(&ubd_lock
);
719 static int ubd_get_config(char *name
, char *str
, int size
, char **error_out
)
724 n
= parse_unit(&name
);
725 if((n
>= MAX_DEV
) || (n
< 0)){
726 *error_out
= "ubd_get_config : device number out of range";
731 spin_lock(&ubd_lock
);
733 if(dev
->file
== NULL
){
734 CONFIG_CHUNK(str
, size
, len
, "", 1);
738 CONFIG_CHUNK(str
, size
, len
, dev
->file
, 0);
740 if(dev
->cow
.file
!= NULL
){
741 CONFIG_CHUNK(str
, size
, len
, ",", 0);
742 CONFIG_CHUNK(str
, size
, len
, dev
->cow
.file
, 1);
744 else CONFIG_CHUNK(str
, size
, len
, "", 1);
747 spin_unlock(&ubd_lock
);
751 static int ubd_id(char **str
, int *start_out
, int *end_out
)
757 *end_out
= MAX_DEV
- 1;
761 static int ubd_remove(int n
)
766 spin_lock(&ubd_lock
);
768 if(ubd_gendisk
[n
] == NULL
)
773 if(dev
->file
== NULL
)
776 /* you cannot remove a open disk */
781 del_gendisk(ubd_gendisk
[n
]);
782 put_disk(ubd_gendisk
[n
]);
783 ubd_gendisk
[n
] = NULL
;
785 if(fake_gendisk
[n
] != NULL
){
786 del_gendisk(fake_gendisk
[n
]);
787 put_disk(fake_gendisk
[n
]);
788 fake_gendisk
[n
] = NULL
;
791 platform_device_unregister(&dev
->pdev
);
792 *dev
= ((struct ubd
) DEFAULT_UBD
);
795 spin_unlock(&ubd_lock
);
799 static struct mc_device ubd_mc
= {
801 .config
= ubd_config
,
802 .get_config
= ubd_get_config
,
804 .remove
= ubd_remove
,
807 static int ubd_mc_init(void)
809 mconsole_register_dev(&ubd_mc
);
813 __initcall(ubd_mc_init
);
815 static struct platform_driver ubd_driver
= {
825 if (register_blkdev(MAJOR_NR
, "ubd"))
828 ubd_queue
= blk_init_queue(do_ubd_request
, &ubd_io_lock
);
830 unregister_blkdev(MAJOR_NR
, "ubd");
834 if (fake_major
!= MAJOR_NR
) {
835 char name
[sizeof("ubd_nnn\0")];
837 snprintf(name
, sizeof(name
), "ubd_%d", fake_major
);
838 if (register_blkdev(fake_major
, "ubd"))
841 platform_driver_register(&ubd_driver
);
842 for (i
= 0; i
< MAX_DEV
; i
++)
847 late_initcall(ubd_init
);
849 int ubd_driver_init(void){
853 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
854 if(global_openflags
.s
){
855 printk(KERN_INFO
"ubd: Synchronous mode\n");
856 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
857 * enough. So use anyway the io thread. */
859 stack
= alloc_stack(0, 0);
860 io_pid
= start_io_thread(stack
+ PAGE_SIZE
- sizeof(void *),
864 "ubd : Failed to start I/O thread (errno = %d) - "
865 "falling back to synchronous I/O\n", -io_pid
);
869 err
= um_request_irq(UBD_IRQ
, thread_fd
, IRQ_READ
, ubd_intr
,
870 IRQF_DISABLED
, "ubd", ubd_dev
);
872 printk(KERN_ERR
"um_request_irq failed - errno = %d\n", -err
);
876 device_initcall(ubd_driver_init
);
878 static int ubd_open(struct inode
*inode
, struct file
*filp
)
880 struct gendisk
*disk
= inode
->i_bdev
->bd_disk
;
881 struct ubd
*dev
= disk
->private_data
;
885 err
= ubd_open_dev(dev
);
887 printk(KERN_ERR
"%s: Can't open \"%s\": errno = %d\n",
888 disk
->disk_name
, dev
->file
, -err
);
893 set_disk_ro(disk
, !dev
->openflags
.w
);
895 /* This should no more be needed. And it didn't work anyway to exclude
896 * read-write remounting of filesystems.*/
897 /*if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){
898 if(--dev->count == 0) ubd_close(dev);
905 static int ubd_release(struct inode
* inode
, struct file
* file
)
907 struct gendisk
*disk
= inode
->i_bdev
->bd_disk
;
908 struct ubd
*dev
= disk
->private_data
;
910 if(--dev
->count
== 0)
915 static void cowify_bitmap(__u64 io_offset
, int length
, unsigned long *cow_mask
,
916 __u64
*cow_offset
, unsigned long *bitmap
,
917 __u64 bitmap_offset
, unsigned long *bitmap_words
,
920 __u64 sector
= io_offset
>> 9;
921 int i
, update_bitmap
= 0;
923 for(i
= 0; i
< length
>> 9; i
++){
925 ubd_set_bit(i
, (unsigned char *) cow_mask
);
926 if(ubd_test_bit(sector
+ i
, (unsigned char *) bitmap
))
930 ubd_set_bit(sector
+ i
, (unsigned char *) bitmap
);
936 *cow_offset
= sector
/ (sizeof(unsigned long) * 8);
938 /* This takes care of the case where we're exactly at the end of the
939 * device, and *cow_offset + 1 is off the end. So, just back it up
940 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
941 * for the original diagnosis.
943 if(*cow_offset
== ((bitmap_len
+ sizeof(unsigned long) - 1) /
944 sizeof(unsigned long) - 1))
947 bitmap_words
[0] = bitmap
[*cow_offset
];
948 bitmap_words
[1] = bitmap
[*cow_offset
+ 1];
950 *cow_offset
*= sizeof(unsigned long);
951 *cow_offset
+= bitmap_offset
;
954 static void cowify_req(struct io_thread_req
*req
, unsigned long *bitmap
,
955 __u64 bitmap_offset
, __u64 bitmap_len
)
957 __u64 sector
= req
->offset
>> 9;
960 if(req
->length
> (sizeof(req
->sector_mask
) * 8) << 9)
961 panic("Operation too long");
963 if(req
->op
== UBD_READ
) {
964 for(i
= 0; i
< req
->length
>> 9; i
++){
965 if(ubd_test_bit(sector
+ i
, (unsigned char *) bitmap
))
966 ubd_set_bit(i
, (unsigned char *)
970 else cowify_bitmap(req
->offset
, req
->length
, &req
->sector_mask
,
971 &req
->cow_offset
, bitmap
, bitmap_offset
,
972 req
->bitmap_words
, bitmap_len
);
975 /* Called with ubd_io_lock held */
976 static int prepare_request(struct request
*req
, struct io_thread_req
*io_req
)
978 struct gendisk
*disk
= req
->rq_disk
;
979 struct ubd
*dev
= disk
->private_data
;
983 /* This should be impossible now */
984 if((rq_data_dir(req
) == WRITE
) && !dev
->openflags
.w
){
985 printk("Write attempted on readonly ubd device %s\n",
991 offset
= ((__u64
) req
->sector
) << 9;
992 len
= req
->current_nr_sectors
<< 9;
994 io_req
->fds
[0] = (dev
->cow
.file
!= NULL
) ? dev
->cow
.fd
: dev
->fd
;
995 io_req
->fds
[1] = dev
->fd
;
996 io_req
->cow_offset
= -1;
997 io_req
->offset
= offset
;
998 io_req
->length
= len
;
1000 io_req
->sector_mask
= 0;
1002 io_req
->op
= (rq_data_dir(req
) == READ
) ? UBD_READ
: UBD_WRITE
;
1003 io_req
->offsets
[0] = 0;
1004 io_req
->offsets
[1] = dev
->cow
.data_offset
;
1005 io_req
->buffer
= req
->buffer
;
1006 io_req
->sectorsize
= 1 << 9;
1008 if(dev
->cow
.file
!= NULL
)
1009 cowify_req(io_req
, dev
->cow
.bitmap
, dev
->cow
.bitmap_offset
,
1010 dev
->cow
.bitmap_len
);
1015 /* Called with ubd_io_lock held */
1016 static void do_ubd_request(request_queue_t
*q
)
1018 struct io_thread_req io_req
;
1019 struct request
*req
;
1022 if(thread_fd
== -1){
1023 while((req
= elv_next_request(q
)) != NULL
){
1024 err
= prepare_request(req
, &io_req
);
1027 __ubd_finish(req
, io_req
.error
);
1032 if(do_ubd
|| (req
= elv_next_request(q
)) == NULL
)
1034 err
= prepare_request(req
, &io_req
);
1036 do_ubd
= ubd_handler
;
1037 n
= os_write_file(thread_fd
, (char *) &io_req
,
1039 if(n
!= sizeof(io_req
))
1040 printk("write to io thread failed, "
1041 "errno = %d\n", -n
);
1046 static int ubd_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
1048 struct ubd
*dev
= bdev
->bd_disk
->private_data
;
1052 geo
->cylinders
= dev
->size
/ (128 * 32 * 512);
1056 static int ubd_ioctl(struct inode
* inode
, struct file
* file
,
1057 unsigned int cmd
, unsigned long arg
)
1059 struct ubd
*dev
= inode
->i_bdev
->bd_disk
->private_data
;
1060 struct hd_driveid ubd_id
= {
1067 struct cdrom_volctrl volume
;
1068 case HDIO_GET_IDENTITY
:
1069 ubd_id
.cyls
= dev
->size
/ (128 * 32 * 512);
1070 if(copy_to_user((char __user
*) arg
, (char *) &ubd_id
,
1076 if(copy_from_user(&volume
, (char __user
*) arg
, sizeof(volume
)))
1078 volume
.channel0
= 255;
1079 volume
.channel1
= 255;
1080 volume
.channel2
= 255;
1081 volume
.channel3
= 255;
1082 if(copy_to_user((char __user
*) arg
, &volume
, sizeof(volume
)))
1089 static int path_requires_switch(char *from_cmdline
, char *from_cow
, char *cow
)
1091 struct uml_stat buf1
, buf2
;
1094 if(from_cmdline
== NULL
)
1096 if(!strcmp(from_cmdline
, from_cow
))
1099 err
= os_stat_file(from_cmdline
, &buf1
);
1101 printk("Couldn't stat '%s', err = %d\n", from_cmdline
, -err
);
1104 err
= os_stat_file(from_cow
, &buf2
);
1106 printk("Couldn't stat '%s', err = %d\n", from_cow
, -err
);
1109 if((buf1
.ust_dev
== buf2
.ust_dev
) && (buf1
.ust_ino
== buf2
.ust_ino
))
1112 printk("Backing file mismatch - \"%s\" requested,\n"
1113 "\"%s\" specified in COW header of \"%s\"\n",
1114 from_cmdline
, from_cow
, cow
);
1118 static int backing_file_mismatch(char *file
, __u64 size
, time_t mtime
)
1120 unsigned long modtime
;
1121 unsigned long long actual
;
1124 err
= os_file_modtime(file
, &modtime
);
1126 printk("Failed to get modification time of backing file "
1127 "\"%s\", err = %d\n", file
, -err
);
1131 err
= os_file_size(file
, &actual
);
1133 printk("Failed to get size of backing file \"%s\", "
1134 "err = %d\n", file
, -err
);
1139 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
1141 printk("Size mismatch (%llu vs %llu) of COW header vs backing "
1142 "file\n", (unsigned long long) size
, actual
);
1145 if(modtime
!= mtime
){
1146 printk("mtime mismatch (%ld vs %ld) of COW header vs backing "
1147 "file\n", mtime
, modtime
);
1153 int read_cow_bitmap(int fd
, void *buf
, int offset
, int len
)
1157 err
= os_seek_file(fd
, offset
);
1161 err
= os_read_file(fd
, buf
, len
);
1168 int open_ubd_file(char *file
, struct openflags
*openflags
, int shared
,
1169 char **backing_file_out
, int *bitmap_offset_out
,
1170 unsigned long *bitmap_len_out
, int *data_offset_out
,
1171 int *create_cow_out
)
1174 unsigned long long size
;
1175 __u32 version
, align
;
1177 int fd
, err
, sectorsize
, asked_switch
, mode
= 0644;
1179 fd
= os_open_file(file
, *openflags
, mode
);
1181 if ((fd
== -ENOENT
) && (create_cow_out
!= NULL
))
1182 *create_cow_out
= 1;
1183 if (!openflags
->w
||
1184 ((fd
!= -EROFS
) && (fd
!= -EACCES
)))
1187 fd
= os_open_file(file
, *openflags
, mode
);
1193 printk("Not locking \"%s\" on the host\n", file
);
1195 err
= os_lock_file(fd
, openflags
->w
);
1197 printk("Failed to lock '%s', err = %d\n", file
, -err
);
1202 /* Successful return case! */
1203 if(backing_file_out
== NULL
)
1206 err
= read_cow_header(file_reader
, &fd
, &version
, &backing_file
, &mtime
,
1207 &size
, §orsize
, &align
, bitmap_offset_out
);
1208 if(err
&& (*backing_file_out
!= NULL
)){
1209 printk("Failed to read COW header from COW file \"%s\", "
1210 "errno = %d\n", file
, -err
);
1216 asked_switch
= path_requires_switch(*backing_file_out
, backing_file
, file
);
1218 /* Allow switching only if no mismatch. */
1219 if (asked_switch
&& !backing_file_mismatch(*backing_file_out
, size
, mtime
)) {
1220 printk("Switching backing file to '%s'\n", *backing_file_out
);
1221 err
= write_cow_header(file
, fd
, *backing_file_out
,
1222 sectorsize
, align
, &size
);
1224 printk("Switch failed, errno = %d\n", -err
);
1228 *backing_file_out
= backing_file
;
1229 err
= backing_file_mismatch(*backing_file_out
, size
, mtime
);
1234 cow_sizes(version
, size
, sectorsize
, align
, *bitmap_offset_out
,
1235 bitmap_len_out
, data_offset_out
);
1243 int create_cow_file(char *cow_file
, char *backing_file
, struct openflags flags
,
1244 int sectorsize
, int alignment
, int *bitmap_offset_out
,
1245 unsigned long *bitmap_len_out
, int *data_offset_out
)
1250 fd
= open_ubd_file(cow_file
, &flags
, 0, NULL
, NULL
, NULL
, NULL
, NULL
);
1253 printk("Open of COW file '%s' failed, errno = %d\n", cow_file
,
1258 err
= init_cow_file(fd
, cow_file
, backing_file
, sectorsize
, alignment
,
1259 bitmap_offset_out
, bitmap_len_out
,
1268 static int update_bitmap(struct io_thread_req
*req
)
1272 if(req
->cow_offset
== -1)
1275 n
= os_seek_file(req
->fds
[1], req
->cow_offset
);
1277 printk("do_io - bitmap lseek failed : err = %d\n", -n
);
1281 n
= os_write_file(req
->fds
[1], &req
->bitmap_words
,
1282 sizeof(req
->bitmap_words
));
1283 if(n
!= sizeof(req
->bitmap_words
)){
1284 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n
,
1292 void do_io(struct io_thread_req
*req
)
1296 int n
, nsectors
, start
, end
, bit
;
1300 nsectors
= req
->length
/ req
->sectorsize
;
1303 bit
= ubd_test_bit(start
, (unsigned char *) &req
->sector_mask
);
1305 while((end
< nsectors
) &&
1306 (ubd_test_bit(end
, (unsigned char *)
1307 &req
->sector_mask
) == bit
))
1310 off
= req
->offset
+ req
->offsets
[bit
] +
1311 start
* req
->sectorsize
;
1312 len
= (end
- start
) * req
->sectorsize
;
1313 buf
= &req
->buffer
[start
* req
->sectorsize
];
1315 err
= os_seek_file(req
->fds
[bit
], off
);
1317 printk("do_io - lseek failed : err = %d\n", -err
);
1321 if(req
->op
== UBD_READ
){
1326 n
= os_read_file(req
->fds
[bit
], buf
, len
);
1328 printk("do_io - read failed, err = %d "
1329 "fd = %d\n", -n
, req
->fds
[bit
]);
1333 } while((n
< len
) && (n
!= 0));
1334 if (n
< len
) memset(&buf
[n
], 0, len
- n
);
1336 n
= os_write_file(req
->fds
[bit
], buf
, len
);
1338 printk("do_io - write failed err = %d "
1339 "fd = %d\n", -n
, req
->fds
[bit
]);
1346 } while(start
< nsectors
);
1348 req
->error
= update_bitmap(req
);
1351 /* Changed in start_io_thread, which is serialized by being called only
1352 * from ubd_init, which is an initcall.
1356 /* Only changed by the io thread */
1359 int io_thread(void *arg
)
1361 struct io_thread_req req
;
1364 ignore_sigwinch_sig();
1366 n
= os_read_file(kernel_fd
, &req
, sizeof(req
));
1367 if(n
!= sizeof(req
)){
1369 printk("io_thread - read failed, fd = %d, "
1370 "err = %d\n", kernel_fd
, -n
);
1372 printk("io_thread - short read, fd = %d, "
1373 "length = %d\n", kernel_fd
, n
);
1379 n
= os_write_file(kernel_fd
, &req
, sizeof(req
));
1380 if(n
!= sizeof(req
))
1381 printk("io_thread - write failed, fd = %d, err = %d\n",