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"
43 #include "kern_util.h"
45 #include "mconsole_kern.h"
55 enum ubd_req
{ UBD_READ
, UBD_WRITE
};
57 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_MUTEX(ubd_lock
);
111 static int ubd_open(struct inode
* inode
, struct file
* filp
);
112 static int ubd_release(struct inode
* inode
, struct file
* file
);
113 static int ubd_ioctl(struct inode
* inode
, struct file
* file
,
114 unsigned int cmd
, unsigned long arg
);
115 static int ubd_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
);
119 static struct block_device_operations ubd_blops
= {
120 .owner
= THIS_MODULE
,
122 .release
= ubd_release
,
124 .getgeo
= ubd_getgeo
,
127 /* Protected by ubd_lock */
128 static int fake_major
= MAJOR_NR
;
129 static struct gendisk
*ubd_gendisk
[MAX_DEV
];
130 static struct gendisk
*fake_gendisk
[MAX_DEV
];
132 #ifdef CONFIG_BLK_DEV_UBD_SYNC
133 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
136 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
139 static struct openflags global_openflags
= OPEN_FLAGS
;
142 /* backing file name */
144 /* backing file fd */
146 unsigned long *bitmap
;
147 unsigned long bitmap_len
;
155 struct list_head restart
;
156 /* name (and fd, below) of the file opened for writing, either the
157 * backing or the cow file. */
162 struct openflags boot_openflags
;
163 struct openflags openflags
;
167 struct platform_device pdev
;
168 struct request_queue
*queue
;
170 struct scatterlist sg
[MAX_SG
];
171 struct request
*request
;
172 int start_sg
, end_sg
;
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, \
193 .lock = SPIN_LOCK_UNLOCKED, \
199 /* Protected by ubd_lock */
200 struct ubd ubd_devs
[MAX_DEV
] = { [ 0 ... MAX_DEV
- 1 ] = DEFAULT_UBD
};
202 /* Only changed by fake_ide_setup which is a setup */
203 static int fake_ide
= 0;
204 static struct proc_dir_entry
*proc_ide_root
= NULL
;
205 static struct proc_dir_entry
*proc_ide
= NULL
;
207 static void make_proc_ide(void)
209 proc_ide_root
= proc_mkdir("ide", NULL
);
210 proc_ide
= proc_mkdir("ide0", proc_ide_root
);
213 static int proc_ide_read_media(char *page
, char **start
, off_t off
, int count
,
214 int *eof
, void *data
)
218 strcpy(page
, "disk\n");
219 len
= strlen("disk\n");
223 if (len
<= 0) return 0;
230 static void make_ide_entries(char *dev_name
)
232 struct proc_dir_entry
*dir
, *ent
;
235 if(proc_ide_root
== NULL
) make_proc_ide();
237 dir
= proc_mkdir(dev_name
, proc_ide
);
240 ent
= create_proc_entry("media", S_IFREG
|S_IRUGO
, dir
);
243 ent
->read_proc
= proc_ide_read_media
;
244 ent
->write_proc
= NULL
;
245 sprintf(name
,"ide0/%s", dev_name
);
246 proc_symlink(dev_name
, proc_ide_root
, name
);
249 static int fake_ide_setup(char *str
)
255 __setup("fake_ide", fake_ide_setup
);
257 __uml_help(fake_ide_setup
,
259 " Create ide0 entries that map onto ubd devices.\n\n"
262 static int parse_unit(char **ptr
)
264 char *str
= *ptr
, *end
;
268 n
= simple_strtoul(str
, &end
, 0);
273 else if (('a' <= *str
) && (*str
<= 'z')) {
281 /* If *index_out == -1 at exit, the passed option was a general one;
282 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it
283 * should not be freed on exit.
285 static int ubd_setup_common(char *str
, int *index_out
, char **error_out
)
288 struct openflags flags
= global_openflags
;
292 if(index_out
) *index_out
= -1;
299 if(!strcmp(str
, "sync")){
300 global_openflags
= of_sync(global_openflags
);
305 major
= simple_strtoul(str
, &end
, 0);
306 if((*end
!= '\0') || (end
== str
)){
307 *error_out
= "Didn't parse major number";
311 mutex_lock(&ubd_lock
);
312 if(fake_major
!= MAJOR_NR
){
313 *error_out
= "Can't assign a fake major twice";
319 printk(KERN_INFO
"Setting extra ubd major number to %d\n",
323 mutex_unlock(&ubd_lock
);
327 n
= parse_unit(&str
);
329 *error_out
= "Couldn't parse device number";
333 *error_out
= "Device number out of range";
338 mutex_lock(&ubd_lock
);
340 ubd_dev
= &ubd_devs
[n
];
341 if(ubd_dev
->file
!= NULL
){
342 *error_out
= "Device is already configured";
350 for (i
= 0; i
< sizeof("rscd="); i
++) {
368 *error_out
= "Expected '=' or flag letter "
376 *error_out
= "Too many flags specified";
378 *error_out
= "Missing '='";
382 backing_file
= strchr(str
, ',');
384 if (backing_file
== NULL
)
385 backing_file
= strchr(str
, ':');
387 if(backing_file
!= NULL
){
389 *error_out
= "Can't specify both 'd' and a cow file";
393 *backing_file
= '\0';
399 ubd_dev
->cow
.file
= backing_file
;
400 ubd_dev
->boot_openflags
= flags
;
402 mutex_unlock(&ubd_lock
);
406 static int ubd_setup(char *str
)
411 err
= ubd_setup_common(str
, NULL
, &error
);
413 printk(KERN_ERR
"Failed to initialize device with \"%s\" : "
418 __setup("ubd", ubd_setup
);
419 __uml_help(ubd_setup
,
420 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
421 " This is used to associate a device with a file in the underlying\n"
422 " filesystem. When specifying two filenames, the first one is the\n"
423 " COW name and the second is the backing file name. As separator you can\n"
424 " use either a ':' or a ',': the first one allows writing things like;\n"
425 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
426 " while with a ',' the shell would not expand the 2nd '~'.\n"
427 " When using only one filename, UML will detect whether to treat it like\n"
428 " a COW file or a backing file. To override this detection, add the 'd'\n"
430 " ubd0d=BackingFile\n"
431 " Usually, there is a filesystem in the file, but \n"
432 " that's not required. Swap devices containing swap files can be\n"
433 " specified like this. Also, a file which doesn't contain a\n"
434 " filesystem can have its contents read in the virtual \n"
435 " machine by running 'dd' on the device. <n> must be in the range\n"
436 " 0 to 7. Appending an 'r' to the number will cause that device\n"
437 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
438 " an 's' will cause data to be written to disk on the host immediately.\n\n"
441 static int udb_setup(char *str
)
443 printk("udb%s specified on command line is almost certainly a ubd -> "
448 __setup("udb", udb_setup
);
449 __uml_help(udb_setup
,
451 " This option is here solely to catch ubd -> udb typos, which can be\n"
452 " to impossible to catch visually unless you specifically look for\n"
453 " them. The only result of any option starting with 'udb' is an error\n"
454 " in the boot output.\n\n"
457 static int fakehd_set
= 0;
458 static int fakehd(char *str
)
460 printk(KERN_INFO
"fakehd : Changing ubd name to \"hd\".\n");
465 __setup("fakehd", fakehd
);
468 " Change the ubd device name to \"hd\".\n\n"
471 static void do_ubd_request(request_queue_t
* q
);
473 /* Only changed by ubd_init, which is an initcall. */
476 static void ubd_end_request(struct request
*req
, int bytes
, int uptodate
)
478 if (!end_that_request_first(req
, uptodate
, bytes
>> 9)) {
479 struct ubd
*dev
= req
->rq_disk
->private_data
;
482 add_disk_randomness(req
->rq_disk
);
483 spin_lock_irqsave(&dev
->lock
, flags
);
484 end_that_request_last(req
, uptodate
);
485 spin_unlock_irqrestore(&dev
->lock
, flags
);
489 /* Callable only from interrupt context - otherwise you need to do
490 * spin_lock_irq()/spin_lock_irqsave() */
491 static inline void ubd_finish(struct request
*req
, int bytes
)
494 ubd_end_request(req
, 0, 0);
497 ubd_end_request(req
, bytes
, 1);
500 static LIST_HEAD(restart
);
502 /* XXX - move this inside ubd_intr. */
503 /* Called without dev->lock held, and only in interrupt context. */
504 static void ubd_handler(void)
506 struct io_thread_req req
;
509 struct list_head
*list
, *next_ele
;
514 n
= os_read_file_k(thread_fd
, &req
, sizeof(req
));
515 if(n
!= sizeof(req
)){
518 printk(KERN_ERR
"spurious interrupt in ubd_handler, "
524 rq
->nr_sectors
-= req
.length
>> 9;
525 if(rq
->nr_sectors
== 0)
526 ubd_finish(rq
, rq
->hard_nr_sectors
<< 9);
528 reactivate_fd(thread_fd
, UBD_IRQ
);
530 list_for_each_safe(list
, next_ele
, &restart
){
531 ubd
= container_of(list
, struct ubd
, restart
);
532 list_del_init(&ubd
->restart
);
533 spin_lock_irqsave(&ubd
->lock
, flags
);
534 do_ubd_request(ubd
->queue
);
535 spin_unlock_irqrestore(&ubd
->lock
, flags
);
539 static irqreturn_t
ubd_intr(int irq
, void *dev
)
545 /* Only changed by ubd_init, which is an initcall. */
546 static int io_pid
= -1;
548 void kill_io_thread(void)
551 os_kill_process(io_pid
, 1);
554 __uml_exitcall(kill_io_thread
);
556 static inline int ubd_file_size(struct ubd
*ubd_dev
, __u64
*size_out
)
560 file
= ubd_dev
->cow
.file
? ubd_dev
->cow
.file
: ubd_dev
->file
;
561 return(os_file_size(file
, size_out
));
564 static void ubd_close_dev(struct ubd
*ubd_dev
)
566 os_close_file(ubd_dev
->fd
);
567 if(ubd_dev
->cow
.file
== NULL
)
570 os_close_file(ubd_dev
->cow
.fd
);
571 vfree(ubd_dev
->cow
.bitmap
);
572 ubd_dev
->cow
.bitmap
= NULL
;
575 static int ubd_open_dev(struct ubd
*ubd_dev
)
577 struct openflags flags
;
579 int err
, create_cow
, *create_ptr
;
582 ubd_dev
->openflags
= ubd_dev
->boot_openflags
;
584 create_ptr
= (ubd_dev
->cow
.file
!= NULL
) ? &create_cow
: NULL
;
585 back_ptr
= ubd_dev
->no_cow
? NULL
: &ubd_dev
->cow
.file
;
587 fd
= open_ubd_file(ubd_dev
->file
, &ubd_dev
->openflags
, ubd_dev
->shared
,
588 back_ptr
, &ubd_dev
->cow
.bitmap_offset
,
589 &ubd_dev
->cow
.bitmap_len
, &ubd_dev
->cow
.data_offset
,
592 if((fd
== -ENOENT
) && create_cow
){
593 fd
= create_cow_file(ubd_dev
->file
, ubd_dev
->cow
.file
,
594 ubd_dev
->openflags
, 1 << 9, PAGE_SIZE
,
595 &ubd_dev
->cow
.bitmap_offset
,
596 &ubd_dev
->cow
.bitmap_len
,
597 &ubd_dev
->cow
.data_offset
);
599 printk(KERN_INFO
"Creating \"%s\" as COW file for "
600 "\"%s\"\n", ubd_dev
->file
, ubd_dev
->cow
.file
);
605 printk("Failed to open '%s', errno = %d\n", ubd_dev
->file
,
611 if(ubd_dev
->cow
.file
!= NULL
){
613 ubd_dev
->cow
.bitmap
= (void *) vmalloc(ubd_dev
->cow
.bitmap_len
);
614 if(ubd_dev
->cow
.bitmap
== NULL
){
615 printk(KERN_ERR
"Failed to vmalloc COW bitmap\n");
618 flush_tlb_kernel_vm();
620 err
= read_cow_bitmap(ubd_dev
->fd
, ubd_dev
->cow
.bitmap
,
621 ubd_dev
->cow
.bitmap_offset
,
622 ubd_dev
->cow
.bitmap_len
);
626 flags
= ubd_dev
->openflags
;
628 err
= open_ubd_file(ubd_dev
->cow
.file
, &flags
, ubd_dev
->shared
, NULL
,
629 NULL
, NULL
, NULL
, NULL
);
630 if(err
< 0) goto error
;
631 ubd_dev
->cow
.fd
= err
;
635 os_close_file(ubd_dev
->fd
);
639 static void ubd_device_release(struct device
*dev
)
641 struct ubd
*ubd_dev
= dev
->driver_data
;
643 blk_cleanup_queue(ubd_dev
->queue
);
644 *ubd_dev
= ((struct ubd
) DEFAULT_UBD
);
647 static int ubd_disk_register(int major
, u64 size
, int unit
,
648 struct gendisk
**disk_out
)
650 struct gendisk
*disk
;
652 disk
= alloc_disk(1 << UBD_SHIFT
);
657 disk
->first_minor
= unit
<< UBD_SHIFT
;
658 disk
->fops
= &ubd_blops
;
659 set_capacity(disk
, size
/ 512);
660 if(major
== MAJOR_NR
)
661 sprintf(disk
->disk_name
, "ubd%c", 'a' + unit
);
663 sprintf(disk
->disk_name
, "ubd_fake%d", unit
);
665 /* sysfs register (not for ide fake devices) */
666 if (major
== MAJOR_NR
) {
667 ubd_devs
[unit
].pdev
.id
= unit
;
668 ubd_devs
[unit
].pdev
.name
= DRIVER_NAME
;
669 ubd_devs
[unit
].pdev
.dev
.release
= ubd_device_release
;
670 ubd_devs
[unit
].pdev
.dev
.driver_data
= &ubd_devs
[unit
];
671 platform_device_register(&ubd_devs
[unit
].pdev
);
672 disk
->driverfs_dev
= &ubd_devs
[unit
].pdev
.dev
;
675 disk
->private_data
= &ubd_devs
[unit
];
676 disk
->queue
= ubd_devs
[unit
].queue
;
683 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9))
685 static int ubd_add(int n
, char **error_out
)
687 struct ubd
*ubd_dev
= &ubd_devs
[n
];
690 if(ubd_dev
->file
== NULL
)
693 err
= ubd_file_size(ubd_dev
, &ubd_dev
->size
);
695 *error_out
= "Couldn't determine size of device's file";
699 ubd_dev
->size
= ROUND_BLOCK(ubd_dev
->size
);
701 INIT_LIST_HEAD(&ubd_dev
->restart
);
704 ubd_dev
->queue
= blk_init_queue(do_ubd_request
, &ubd_dev
->lock
);
705 if (ubd_dev
->queue
== NULL
) {
706 *error_out
= "Failed to initialize device queue";
709 ubd_dev
->queue
->queuedata
= ubd_dev
;
711 blk_queue_max_hw_segments(ubd_dev
->queue
, MAX_SG
);
712 err
= ubd_disk_register(MAJOR_NR
, ubd_dev
->size
, n
, &ubd_gendisk
[n
]);
714 *error_out
= "Failed to register device";
718 if(fake_major
!= MAJOR_NR
)
719 ubd_disk_register(fake_major
, ubd_dev
->size
, n
,
722 /* perhaps this should also be under the "if (fake_major)" above */
723 /* using the fake_disk->disk_name and also the fakehd_set name */
725 make_ide_entries(ubd_gendisk
[n
]->disk_name
);
732 blk_cleanup_queue(ubd_dev
->queue
);
736 static int ubd_config(char *str
, char **error_out
)
740 /* This string is possibly broken up and stored, so it's only
741 * freed if ubd_setup_common fails, or if only general options
744 str
= kstrdup(str
, GFP_KERNEL
);
746 *error_out
= "Failed to allocate memory";
750 ret
= ubd_setup_common(str
, &n
, error_out
);
759 mutex_lock(&ubd_lock
);
760 ret
= ubd_add(n
, error_out
);
762 ubd_devs
[n
].file
= NULL
;
763 mutex_unlock(&ubd_lock
);
773 static int ubd_get_config(char *name
, char *str
, int size
, char **error_out
)
778 n
= parse_unit(&name
);
779 if((n
>= MAX_DEV
) || (n
< 0)){
780 *error_out
= "ubd_get_config : device number out of range";
784 ubd_dev
= &ubd_devs
[n
];
785 mutex_lock(&ubd_lock
);
787 if(ubd_dev
->file
== NULL
){
788 CONFIG_CHUNK(str
, size
, len
, "", 1);
792 CONFIG_CHUNK(str
, size
, len
, ubd_dev
->file
, 0);
794 if(ubd_dev
->cow
.file
!= NULL
){
795 CONFIG_CHUNK(str
, size
, len
, ",", 0);
796 CONFIG_CHUNK(str
, size
, len
, ubd_dev
->cow
.file
, 1);
798 else CONFIG_CHUNK(str
, size
, len
, "", 1);
801 mutex_unlock(&ubd_lock
);
805 static int ubd_id(char **str
, int *start_out
, int *end_out
)
811 *end_out
= MAX_DEV
- 1;
815 static int ubd_remove(int n
, char **error_out
)
817 struct gendisk
*disk
= ubd_gendisk
[n
];
821 mutex_lock(&ubd_lock
);
823 ubd_dev
= &ubd_devs
[n
];
825 if(ubd_dev
->file
== NULL
)
828 /* you cannot remove a open disk */
830 if(ubd_dev
->count
> 0)
833 ubd_gendisk
[n
] = NULL
;
839 if(fake_gendisk
[n
] != NULL
){
840 del_gendisk(fake_gendisk
[n
]);
841 put_disk(fake_gendisk
[n
]);
842 fake_gendisk
[n
] = NULL
;
846 platform_device_unregister(&ubd_dev
->pdev
);
848 mutex_unlock(&ubd_lock
);
852 /* All these are called by mconsole in process context and without
853 * ubd-specific locks. The structure itself is const except for .list.
855 static struct mc_device ubd_mc
= {
856 .list
= LIST_HEAD_INIT(ubd_mc
.list
),
858 .config
= ubd_config
,
859 .get_config
= ubd_get_config
,
861 .remove
= ubd_remove
,
864 static int __init
ubd_mc_init(void)
866 mconsole_register_dev(&ubd_mc
);
870 __initcall(ubd_mc_init
);
872 static int __init
ubd0_init(void)
874 struct ubd
*ubd_dev
= &ubd_devs
[0];
876 mutex_lock(&ubd_lock
);
877 if(ubd_dev
->file
== NULL
)
878 ubd_dev
->file
= "root_fs";
879 mutex_unlock(&ubd_lock
);
884 __initcall(ubd0_init
);
886 /* Used in ubd_init, which is an initcall */
887 static struct platform_driver ubd_driver
= {
893 static int __init
ubd_init(void)
898 if (register_blkdev(MAJOR_NR
, "ubd"))
901 if (fake_major
!= MAJOR_NR
) {
902 char name
[sizeof("ubd_nnn\0")];
904 snprintf(name
, sizeof(name
), "ubd_%d", fake_major
);
905 if (register_blkdev(fake_major
, "ubd"))
908 platform_driver_register(&ubd_driver
);
909 mutex_lock(&ubd_lock
);
910 for (i
= 0; i
< MAX_DEV
; i
++){
911 err
= ubd_add(i
, &error
);
913 printk(KERN_ERR
"Failed to initialize ubd device %d :"
916 mutex_unlock(&ubd_lock
);
920 late_initcall(ubd_init
);
922 static int __init
ubd_driver_init(void){
926 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
927 if(global_openflags
.s
){
928 printk(KERN_INFO
"ubd: Synchronous mode\n");
929 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
930 * enough. So use anyway the io thread. */
932 stack
= alloc_stack(0, 0);
933 io_pid
= start_io_thread(stack
+ PAGE_SIZE
- sizeof(void *),
937 "ubd : Failed to start I/O thread (errno = %d) - "
938 "falling back to synchronous I/O\n", -io_pid
);
942 err
= um_request_irq(UBD_IRQ
, thread_fd
, IRQ_READ
, ubd_intr
,
943 IRQF_DISABLED
, "ubd", ubd_devs
);
945 printk(KERN_ERR
"um_request_irq failed - errno = %d\n", -err
);
949 device_initcall(ubd_driver_init
);
951 static int ubd_open(struct inode
*inode
, struct file
*filp
)
953 struct gendisk
*disk
= inode
->i_bdev
->bd_disk
;
954 struct ubd
*ubd_dev
= disk
->private_data
;
957 if(ubd_dev
->count
== 0){
958 err
= ubd_open_dev(ubd_dev
);
960 printk(KERN_ERR
"%s: Can't open \"%s\": errno = %d\n",
961 disk
->disk_name
, ubd_dev
->file
, -err
);
966 set_disk_ro(disk
, !ubd_dev
->openflags
.w
);
968 /* This should no more be needed. And it didn't work anyway to exclude
969 * read-write remounting of filesystems.*/
970 /*if((filp->f_mode & FMODE_WRITE) && !ubd_dev->openflags.w){
971 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
978 static int ubd_release(struct inode
* inode
, struct file
* file
)
980 struct gendisk
*disk
= inode
->i_bdev
->bd_disk
;
981 struct ubd
*ubd_dev
= disk
->private_data
;
983 if(--ubd_dev
->count
== 0)
984 ubd_close_dev(ubd_dev
);
988 static void cowify_bitmap(__u64 io_offset
, int length
, unsigned long *cow_mask
,
989 __u64
*cow_offset
, unsigned long *bitmap
,
990 __u64 bitmap_offset
, unsigned long *bitmap_words
,
993 __u64 sector
= io_offset
>> 9;
994 int i
, update_bitmap
= 0;
996 for(i
= 0; i
< length
>> 9; i
++){
998 ubd_set_bit(i
, (unsigned char *) cow_mask
);
999 if(ubd_test_bit(sector
+ i
, (unsigned char *) bitmap
))
1003 ubd_set_bit(sector
+ i
, (unsigned char *) bitmap
);
1009 *cow_offset
= sector
/ (sizeof(unsigned long) * 8);
1011 /* This takes care of the case where we're exactly at the end of the
1012 * device, and *cow_offset + 1 is off the end. So, just back it up
1013 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
1014 * for the original diagnosis.
1016 if(*cow_offset
== ((bitmap_len
+ sizeof(unsigned long) - 1) /
1017 sizeof(unsigned long) - 1))
1020 bitmap_words
[0] = bitmap
[*cow_offset
];
1021 bitmap_words
[1] = bitmap
[*cow_offset
+ 1];
1023 *cow_offset
*= sizeof(unsigned long);
1024 *cow_offset
+= bitmap_offset
;
1027 static void cowify_req(struct io_thread_req
*req
, unsigned long *bitmap
,
1028 __u64 bitmap_offset
, __u64 bitmap_len
)
1030 __u64 sector
= req
->offset
>> 9;
1033 if(req
->length
> (sizeof(req
->sector_mask
) * 8) << 9)
1034 panic("Operation too long");
1036 if(req
->op
== UBD_READ
) {
1037 for(i
= 0; i
< req
->length
>> 9; i
++){
1038 if(ubd_test_bit(sector
+ i
, (unsigned char *) bitmap
))
1039 ubd_set_bit(i
, (unsigned char *)
1043 else cowify_bitmap(req
->offset
, req
->length
, &req
->sector_mask
,
1044 &req
->cow_offset
, bitmap
, bitmap_offset
,
1045 req
->bitmap_words
, bitmap_len
);
1048 /* Called with dev->lock held */
1049 static void prepare_request(struct request
*req
, struct io_thread_req
*io_req
,
1050 unsigned long long offset
, int page_offset
,
1051 int len
, struct page
*page
)
1053 struct gendisk
*disk
= req
->rq_disk
;
1054 struct ubd
*ubd_dev
= disk
->private_data
;
1057 io_req
->fds
[0] = (ubd_dev
->cow
.file
!= NULL
) ? ubd_dev
->cow
.fd
:
1059 io_req
->fds
[1] = ubd_dev
->fd
;
1060 io_req
->cow_offset
= -1;
1061 io_req
->offset
= offset
;
1062 io_req
->length
= len
;
1064 io_req
->sector_mask
= 0;
1066 io_req
->op
= (rq_data_dir(req
) == READ
) ? UBD_READ
: UBD_WRITE
;
1067 io_req
->offsets
[0] = 0;
1068 io_req
->offsets
[1] = ubd_dev
->cow
.data_offset
;
1069 io_req
->buffer
= page_address(page
) + page_offset
;
1070 io_req
->sectorsize
= 1 << 9;
1072 if(ubd_dev
->cow
.file
!= NULL
)
1073 cowify_req(io_req
, ubd_dev
->cow
.bitmap
,
1074 ubd_dev
->cow
.bitmap_offset
, ubd_dev
->cow
.bitmap_len
);
1078 /* Called with dev->lock held */
1079 static void do_ubd_request(request_queue_t
*q
)
1081 struct io_thread_req io_req
;
1082 struct request
*req
;
1086 struct ubd
*dev
= q
->queuedata
;
1087 if(dev
->end_sg
== 0){
1088 struct request
*req
= elv_next_request(q
);
1093 blkdev_dequeue_request(req
);
1095 dev
->end_sg
= blk_rq_map_sg(q
, req
, dev
->sg
);
1099 while(dev
->start_sg
< dev
->end_sg
){
1100 struct scatterlist
*sg
= &dev
->sg
[dev
->start_sg
];
1102 prepare_request(req
, &io_req
,
1103 (unsigned long long) req
->sector
<< 9,
1104 sg
->offset
, sg
->length
, sg
->page
);
1106 n
= os_write_file_k(thread_fd
, (char *) &io_req
,
1108 if(n
!= sizeof(io_req
)){
1110 printk("write to io thread failed, "
1111 "errno = %d\n", -n
);
1112 else if(list_empty(&dev
->restart
))
1113 list_add(&dev
->restart
, &restart
);
1117 req
->sector
+= sg
->length
>> 9;
1121 dev
->request
= NULL
;
1125 static int ubd_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
1127 struct ubd
*ubd_dev
= bdev
->bd_disk
->private_data
;
1131 geo
->cylinders
= ubd_dev
->size
/ (128 * 32 * 512);
1135 static int ubd_ioctl(struct inode
* inode
, struct file
* file
,
1136 unsigned int cmd
, unsigned long arg
)
1138 struct ubd
*ubd_dev
= inode
->i_bdev
->bd_disk
->private_data
;
1139 struct hd_driveid ubd_id
= {
1146 struct cdrom_volctrl volume
;
1147 case HDIO_GET_IDENTITY
:
1148 ubd_id
.cyls
= ubd_dev
->size
/ (128 * 32 * 512);
1149 if(copy_to_user((char __user
*) arg
, (char *) &ubd_id
,
1155 if(copy_from_user(&volume
, (char __user
*) arg
, sizeof(volume
)))
1157 volume
.channel0
= 255;
1158 volume
.channel1
= 255;
1159 volume
.channel2
= 255;
1160 volume
.channel3
= 255;
1161 if(copy_to_user((char __user
*) arg
, &volume
, sizeof(volume
)))
1168 static int path_requires_switch(char *from_cmdline
, char *from_cow
, char *cow
)
1170 struct uml_stat buf1
, buf2
;
1173 if(from_cmdline
== NULL
)
1175 if(!strcmp(from_cmdline
, from_cow
))
1178 err
= os_stat_file(from_cmdline
, &buf1
);
1180 printk("Couldn't stat '%s', err = %d\n", from_cmdline
, -err
);
1183 err
= os_stat_file(from_cow
, &buf2
);
1185 printk("Couldn't stat '%s', err = %d\n", from_cow
, -err
);
1188 if((buf1
.ust_dev
== buf2
.ust_dev
) && (buf1
.ust_ino
== buf2
.ust_ino
))
1191 printk("Backing file mismatch - \"%s\" requested,\n"
1192 "\"%s\" specified in COW header of \"%s\"\n",
1193 from_cmdline
, from_cow
, cow
);
1197 static int backing_file_mismatch(char *file
, __u64 size
, time_t mtime
)
1199 unsigned long modtime
;
1200 unsigned long long actual
;
1203 err
= os_file_modtime(file
, &modtime
);
1205 printk("Failed to get modification time of backing file "
1206 "\"%s\", err = %d\n", file
, -err
);
1210 err
= os_file_size(file
, &actual
);
1212 printk("Failed to get size of backing file \"%s\", "
1213 "err = %d\n", file
, -err
);
1218 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
1220 printk("Size mismatch (%llu vs %llu) of COW header vs backing "
1221 "file\n", (unsigned long long) size
, actual
);
1224 if(modtime
!= mtime
){
1225 printk("mtime mismatch (%ld vs %ld) of COW header vs backing "
1226 "file\n", mtime
, modtime
);
1232 int read_cow_bitmap(int fd
, void *buf
, int offset
, int len
)
1236 err
= os_seek_file(fd
, offset
);
1240 err
= os_read_file(fd
, buf
, len
);
1247 int open_ubd_file(char *file
, struct openflags
*openflags
, int shared
,
1248 char **backing_file_out
, int *bitmap_offset_out
,
1249 unsigned long *bitmap_len_out
, int *data_offset_out
,
1250 int *create_cow_out
)
1253 unsigned long long size
;
1254 __u32 version
, align
;
1256 int fd
, err
, sectorsize
, asked_switch
, mode
= 0644;
1258 fd
= os_open_file(file
, *openflags
, mode
);
1260 if ((fd
== -ENOENT
) && (create_cow_out
!= NULL
))
1261 *create_cow_out
= 1;
1262 if (!openflags
->w
||
1263 ((fd
!= -EROFS
) && (fd
!= -EACCES
)))
1266 fd
= os_open_file(file
, *openflags
, mode
);
1272 printk("Not locking \"%s\" on the host\n", file
);
1274 err
= os_lock_file(fd
, openflags
->w
);
1276 printk("Failed to lock '%s', err = %d\n", file
, -err
);
1281 /* Successful return case! */
1282 if(backing_file_out
== NULL
)
1285 err
= read_cow_header(file_reader
, &fd
, &version
, &backing_file
, &mtime
,
1286 &size
, §orsize
, &align
, bitmap_offset_out
);
1287 if(err
&& (*backing_file_out
!= NULL
)){
1288 printk("Failed to read COW header from COW file \"%s\", "
1289 "errno = %d\n", file
, -err
);
1295 asked_switch
= path_requires_switch(*backing_file_out
, backing_file
, file
);
1297 /* Allow switching only if no mismatch. */
1298 if (asked_switch
&& !backing_file_mismatch(*backing_file_out
, size
, mtime
)) {
1299 printk("Switching backing file to '%s'\n", *backing_file_out
);
1300 err
= write_cow_header(file
, fd
, *backing_file_out
,
1301 sectorsize
, align
, &size
);
1303 printk("Switch failed, errno = %d\n", -err
);
1307 *backing_file_out
= backing_file
;
1308 err
= backing_file_mismatch(*backing_file_out
, size
, mtime
);
1313 cow_sizes(version
, size
, sectorsize
, align
, *bitmap_offset_out
,
1314 bitmap_len_out
, data_offset_out
);
1322 int create_cow_file(char *cow_file
, char *backing_file
, struct openflags flags
,
1323 int sectorsize
, int alignment
, int *bitmap_offset_out
,
1324 unsigned long *bitmap_len_out
, int *data_offset_out
)
1329 fd
= open_ubd_file(cow_file
, &flags
, 0, NULL
, NULL
, NULL
, NULL
, NULL
);
1332 printk("Open of COW file '%s' failed, errno = %d\n", cow_file
,
1337 err
= init_cow_file(fd
, cow_file
, backing_file
, sectorsize
, alignment
,
1338 bitmap_offset_out
, bitmap_len_out
,
1347 static int update_bitmap(struct io_thread_req
*req
)
1351 if(req
->cow_offset
== -1)
1354 n
= os_seek_file(req
->fds
[1], req
->cow_offset
);
1356 printk("do_io - bitmap lseek failed : err = %d\n", -n
);
1360 n
= os_write_file_k(req
->fds
[1], &req
->bitmap_words
,
1361 sizeof(req
->bitmap_words
));
1362 if(n
!= sizeof(req
->bitmap_words
)){
1363 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n
,
1371 void do_io(struct io_thread_req
*req
)
1375 int n
, nsectors
, start
, end
, bit
;
1379 nsectors
= req
->length
/ req
->sectorsize
;
1382 bit
= ubd_test_bit(start
, (unsigned char *) &req
->sector_mask
);
1384 while((end
< nsectors
) &&
1385 (ubd_test_bit(end
, (unsigned char *)
1386 &req
->sector_mask
) == bit
))
1389 off
= req
->offset
+ req
->offsets
[bit
] +
1390 start
* req
->sectorsize
;
1391 len
= (end
- start
) * req
->sectorsize
;
1392 buf
= &req
->buffer
[start
* req
->sectorsize
];
1394 err
= os_seek_file(req
->fds
[bit
], off
);
1396 printk("do_io - lseek failed : err = %d\n", -err
);
1400 if(req
->op
== UBD_READ
){
1405 n
= os_read_file_k(req
->fds
[bit
], buf
, len
);
1407 printk("do_io - read failed, err = %d "
1408 "fd = %d\n", -n
, req
->fds
[bit
]);
1412 } while((n
< len
) && (n
!= 0));
1413 if (n
< len
) memset(&buf
[n
], 0, len
- n
);
1415 n
= os_write_file_k(req
->fds
[bit
], buf
, len
);
1417 printk("do_io - write failed err = %d "
1418 "fd = %d\n", -n
, req
->fds
[bit
]);
1425 } while(start
< nsectors
);
1427 req
->error
= update_bitmap(req
);
1430 /* Changed in start_io_thread, which is serialized by being called only
1431 * from ubd_init, which is an initcall.
1435 /* Only changed by the io thread. XXX: currently unused. */
1436 static int io_count
= 0;
1438 int io_thread(void *arg
)
1440 struct io_thread_req req
;
1443 ignore_sigwinch_sig();
1445 n
= os_read_file_k(kernel_fd
, &req
, sizeof(req
));
1446 if(n
!= sizeof(req
)){
1448 printk("io_thread - read failed, fd = %d, "
1449 "err = %d\n", kernel_fd
, -n
);
1451 printk("io_thread - short read, fd = %d, "
1452 "length = %d\n", kernel_fd
, n
);
1458 n
= os_write_file_k(kernel_fd
, &req
, sizeof(req
));
1459 if(n
!= sizeof(req
))
1460 printk("io_thread - write failed, fd = %d, err = %d\n",