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/kernel.h"
24 #include "linux/module.h"
25 #include "linux/blkdev.h"
26 #include "linux/hdreg.h"
27 #include "linux/init.h"
28 #include "linux/cdrom.h"
29 #include "linux/proc_fs.h"
30 #include "linux/ctype.h"
31 #include "linux/capability.h"
33 #include "linux/vmalloc.h"
34 #include "linux/blkpg.h"
35 #include "linux/genhd.h"
36 #include "linux/spinlock.h"
37 #include "linux/platform_device.h"
38 #include "linux/scatterlist.h"
39 #include "asm/segment.h"
40 #include "asm/uaccess.h"
42 #include "asm/types.h"
43 #include "asm/tlbflush.h"
45 #include "kern_util.h"
47 #include "mconsole_kern.h"
57 enum ubd_req
{ UBD_READ
, UBD_WRITE
};
59 struct io_thread_req
{
63 unsigned long offsets
[2];
64 unsigned long long offset
;
68 unsigned long sector_mask
;
69 unsigned long long cow_offset
;
70 unsigned long bitmap_words
[2];
74 extern int open_ubd_file(char *file
, struct openflags
*openflags
, int shared
,
75 char **backing_file_out
, int *bitmap_offset_out
,
76 unsigned long *bitmap_len_out
, int *data_offset_out
,
78 extern int create_cow_file(char *cow_file
, char *backing_file
,
79 struct openflags flags
, int sectorsize
,
80 int alignment
, int *bitmap_offset_out
,
81 unsigned long *bitmap_len_out
,
82 int *data_offset_out
);
83 extern int read_cow_bitmap(int fd
, void *buf
, int offset
, int len
);
84 extern void do_io(struct io_thread_req
*req
);
86 static inline int ubd_test_bit(__u64 bit
, unsigned char *data
)
91 bits
= sizeof(data
[0]) * 8;
94 return (data
[n
] & (1 << off
)) != 0;
97 static inline void ubd_set_bit(__u64 bit
, unsigned char *data
)
102 bits
= sizeof(data
[0]) * 8;
105 data
[n
] |= (1 << off
);
107 /*End stuff from ubd_user.h*/
109 #define DRIVER_NAME "uml-blkdev"
111 static DEFINE_MUTEX(ubd_lock
);
113 static int ubd_open(struct inode
* inode
, struct file
* filp
);
114 static int ubd_release(struct inode
* inode
, struct file
* file
);
115 static int ubd_ioctl(struct inode
* inode
, struct file
* file
,
116 unsigned int cmd
, unsigned long arg
);
117 static int ubd_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
);
121 static struct block_device_operations ubd_blops
= {
122 .owner
= THIS_MODULE
,
124 .release
= ubd_release
,
126 .getgeo
= ubd_getgeo
,
129 /* Protected by ubd_lock */
130 static int fake_major
= MAJOR_NR
;
131 static struct gendisk
*ubd_gendisk
[MAX_DEV
];
132 static struct gendisk
*fake_gendisk
[MAX_DEV
];
134 #ifdef CONFIG_BLK_DEV_UBD_SYNC
135 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
138 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
141 static struct openflags global_openflags
= OPEN_FLAGS
;
144 /* backing file name */
146 /* backing file fd */
148 unsigned long *bitmap
;
149 unsigned long bitmap_len
;
157 struct list_head restart
;
158 /* name (and fd, below) of the file opened for writing, either the
159 * backing or the cow file. */
164 struct openflags boot_openflags
;
165 struct openflags openflags
;
169 struct platform_device pdev
;
170 struct request_queue
*queue
;
172 struct scatterlist sg
[MAX_SG
];
173 struct request
*request
;
174 int start_sg
, end_sg
;
177 #define DEFAULT_COW { \
181 .bitmap_offset = 0, \
185 #define DEFAULT_UBD { \
190 .boot_openflags = OPEN_FLAGS, \
191 .openflags = OPEN_FLAGS, \
194 .cow = DEFAULT_COW, \
195 .lock = SPIN_LOCK_UNLOCKED, \
201 /* Protected by ubd_lock */
202 struct ubd ubd_devs
[MAX_DEV
] = { [ 0 ... MAX_DEV
- 1 ] = DEFAULT_UBD
};
204 /* Only changed by fake_ide_setup which is a setup */
205 static int fake_ide
= 0;
206 static struct proc_dir_entry
*proc_ide_root
= NULL
;
207 static struct proc_dir_entry
*proc_ide
= NULL
;
209 static void make_proc_ide(void)
211 proc_ide_root
= proc_mkdir("ide", NULL
);
212 proc_ide
= proc_mkdir("ide0", proc_ide_root
);
215 static int proc_ide_read_media(char *page
, char **start
, off_t off
, int count
,
216 int *eof
, void *data
)
220 strcpy(page
, "disk\n");
221 len
= strlen("disk\n");
225 if (len
<= 0) return 0;
232 static void make_ide_entries(char *dev_name
)
234 struct proc_dir_entry
*dir
, *ent
;
237 if(proc_ide_root
== NULL
) make_proc_ide();
239 dir
= proc_mkdir(dev_name
, proc_ide
);
242 ent
= create_proc_entry("media", S_IFREG
|S_IRUGO
, dir
);
245 ent
->read_proc
= proc_ide_read_media
;
246 ent
->write_proc
= NULL
;
247 sprintf(name
,"ide0/%s", dev_name
);
248 proc_symlink(dev_name
, proc_ide_root
, name
);
251 static int fake_ide_setup(char *str
)
257 __setup("fake_ide", fake_ide_setup
);
259 __uml_help(fake_ide_setup
,
261 " Create ide0 entries that map onto ubd devices.\n\n"
264 static int parse_unit(char **ptr
)
266 char *str
= *ptr
, *end
;
270 n
= simple_strtoul(str
, &end
, 0);
275 else if (('a' <= *str
) && (*str
<= 'z')) {
283 /* If *index_out == -1 at exit, the passed option was a general one;
284 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it
285 * should not be freed on exit.
287 static int ubd_setup_common(char *str
, int *index_out
, char **error_out
)
290 struct openflags flags
= global_openflags
;
294 if(index_out
) *index_out
= -1;
301 if(!strcmp(str
, "sync")){
302 global_openflags
= of_sync(global_openflags
);
307 major
= simple_strtoul(str
, &end
, 0);
308 if((*end
!= '\0') || (end
== str
)){
309 *error_out
= "Didn't parse major number";
313 mutex_lock(&ubd_lock
);
314 if(fake_major
!= MAJOR_NR
){
315 *error_out
= "Can't assign a fake major twice";
321 printk(KERN_INFO
"Setting extra ubd major number to %d\n",
325 mutex_unlock(&ubd_lock
);
329 n
= parse_unit(&str
);
331 *error_out
= "Couldn't parse device number";
335 *error_out
= "Device number out of range";
340 mutex_lock(&ubd_lock
);
342 ubd_dev
= &ubd_devs
[n
];
343 if(ubd_dev
->file
!= NULL
){
344 *error_out
= "Device is already configured";
352 for (i
= 0; i
< sizeof("rscd="); i
++) {
370 *error_out
= "Expected '=' or flag letter "
378 *error_out
= "Too many flags specified";
380 *error_out
= "Missing '='";
384 backing_file
= strchr(str
, ',');
386 if (backing_file
== NULL
)
387 backing_file
= strchr(str
, ':');
389 if(backing_file
!= NULL
){
391 *error_out
= "Can't specify both 'd' and a cow file";
395 *backing_file
= '\0';
401 ubd_dev
->cow
.file
= backing_file
;
402 ubd_dev
->boot_openflags
= flags
;
404 mutex_unlock(&ubd_lock
);
408 static int ubd_setup(char *str
)
413 err
= ubd_setup_common(str
, NULL
, &error
);
415 printk(KERN_ERR
"Failed to initialize device with \"%s\" : "
420 __setup("ubd", ubd_setup
);
421 __uml_help(ubd_setup
,
422 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
423 " This is used to associate a device with a file in the underlying\n"
424 " filesystem. When specifying two filenames, the first one is the\n"
425 " COW name and the second is the backing file name. As separator you can\n"
426 " use either a ':' or a ',': the first one allows writing things like;\n"
427 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
428 " while with a ',' the shell would not expand the 2nd '~'.\n"
429 " When using only one filename, UML will detect whether to treat it like\n"
430 " a COW file or a backing file. To override this detection, add the 'd'\n"
432 " ubd0d=BackingFile\n"
433 " Usually, there is a filesystem in the file, but \n"
434 " that's not required. Swap devices containing swap files can be\n"
435 " specified like this. Also, a file which doesn't contain a\n"
436 " filesystem can have its contents read in the virtual \n"
437 " machine by running 'dd' on the device. <n> must be in the range\n"
438 " 0 to 7. Appending an 'r' to the number will cause that device\n"
439 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
440 " an 's' will cause data to be written to disk on the host immediately.\n\n"
443 static int udb_setup(char *str
)
445 printk("udb%s specified on command line is almost certainly a ubd -> "
450 __setup("udb", udb_setup
);
451 __uml_help(udb_setup
,
453 " This option is here solely to catch ubd -> udb typos, which can be\n"
454 " to impossible to catch visually unless you specifically look for\n"
455 " them. The only result of any option starting with 'udb' is an error\n"
456 " in the boot output.\n\n"
459 static int fakehd_set
= 0;
460 static int fakehd(char *str
)
462 printk(KERN_INFO
"fakehd : Changing ubd name to \"hd\".\n");
467 __setup("fakehd", fakehd
);
470 " Change the ubd device name to \"hd\".\n\n"
473 static void do_ubd_request(struct request_queue
* q
);
475 /* Only changed by ubd_init, which is an initcall. */
478 static void ubd_end_request(struct request
*req
, int bytes
, int uptodate
)
480 if (!end_that_request_first(req
, uptodate
, bytes
>> 9)) {
481 struct ubd
*dev
= req
->rq_disk
->private_data
;
484 add_disk_randomness(req
->rq_disk
);
485 spin_lock_irqsave(&dev
->lock
, flags
);
486 end_that_request_last(req
, uptodate
);
487 spin_unlock_irqrestore(&dev
->lock
, flags
);
491 /* Callable only from interrupt context - otherwise you need to do
492 * spin_lock_irq()/spin_lock_irqsave() */
493 static inline void ubd_finish(struct request
*req
, int bytes
)
496 ubd_end_request(req
, 0, 0);
499 ubd_end_request(req
, bytes
, 1);
502 static LIST_HEAD(restart
);
504 /* XXX - move this inside ubd_intr. */
505 /* Called without dev->lock held, and only in interrupt context. */
506 static void ubd_handler(void)
508 struct io_thread_req
*req
;
511 struct list_head
*list
, *next_ele
;
516 n
= os_read_file(thread_fd
, &req
,
517 sizeof(struct io_thread_req
*));
518 if(n
!= sizeof(req
)){
521 printk(KERN_ERR
"spurious interrupt in ubd_handler, "
527 rq
->nr_sectors
-= req
->length
>> 9;
528 if(rq
->nr_sectors
== 0)
529 ubd_finish(rq
, rq
->hard_nr_sectors
<< 9);
532 reactivate_fd(thread_fd
, UBD_IRQ
);
534 list_for_each_safe(list
, next_ele
, &restart
){
535 ubd
= container_of(list
, struct ubd
, restart
);
536 list_del_init(&ubd
->restart
);
537 spin_lock_irqsave(&ubd
->lock
, flags
);
538 do_ubd_request(ubd
->queue
);
539 spin_unlock_irqrestore(&ubd
->lock
, flags
);
543 static irqreturn_t
ubd_intr(int irq
, void *dev
)
549 /* Only changed by ubd_init, which is an initcall. */
550 static int io_pid
= -1;
552 void kill_io_thread(void)
555 os_kill_process(io_pid
, 1);
558 __uml_exitcall(kill_io_thread
);
560 static inline int ubd_file_size(struct ubd
*ubd_dev
, __u64
*size_out
)
564 file
= ubd_dev
->cow
.file
? ubd_dev
->cow
.file
: ubd_dev
->file
;
565 return os_file_size(file
, size_out
);
568 static void ubd_close_dev(struct ubd
*ubd_dev
)
570 os_close_file(ubd_dev
->fd
);
571 if(ubd_dev
->cow
.file
== NULL
)
574 os_close_file(ubd_dev
->cow
.fd
);
575 vfree(ubd_dev
->cow
.bitmap
);
576 ubd_dev
->cow
.bitmap
= NULL
;
579 static int ubd_open_dev(struct ubd
*ubd_dev
)
581 struct openflags flags
;
583 int err
, create_cow
, *create_ptr
;
586 ubd_dev
->openflags
= ubd_dev
->boot_openflags
;
588 create_ptr
= (ubd_dev
->cow
.file
!= NULL
) ? &create_cow
: NULL
;
589 back_ptr
= ubd_dev
->no_cow
? NULL
: &ubd_dev
->cow
.file
;
591 fd
= open_ubd_file(ubd_dev
->file
, &ubd_dev
->openflags
, ubd_dev
->shared
,
592 back_ptr
, &ubd_dev
->cow
.bitmap_offset
,
593 &ubd_dev
->cow
.bitmap_len
, &ubd_dev
->cow
.data_offset
,
596 if((fd
== -ENOENT
) && create_cow
){
597 fd
= create_cow_file(ubd_dev
->file
, ubd_dev
->cow
.file
,
598 ubd_dev
->openflags
, 1 << 9, PAGE_SIZE
,
599 &ubd_dev
->cow
.bitmap_offset
,
600 &ubd_dev
->cow
.bitmap_len
,
601 &ubd_dev
->cow
.data_offset
);
603 printk(KERN_INFO
"Creating \"%s\" as COW file for "
604 "\"%s\"\n", ubd_dev
->file
, ubd_dev
->cow
.file
);
609 printk("Failed to open '%s', errno = %d\n", ubd_dev
->file
,
615 if(ubd_dev
->cow
.file
!= NULL
){
616 blk_queue_max_sectors(ubd_dev
->queue
, 8 * sizeof(long));
619 ubd_dev
->cow
.bitmap
= vmalloc(ubd_dev
->cow
.bitmap_len
);
620 if(ubd_dev
->cow
.bitmap
== NULL
){
621 printk(KERN_ERR
"Failed to vmalloc COW bitmap\n");
624 flush_tlb_kernel_vm();
626 err
= read_cow_bitmap(ubd_dev
->fd
, ubd_dev
->cow
.bitmap
,
627 ubd_dev
->cow
.bitmap_offset
,
628 ubd_dev
->cow
.bitmap_len
);
632 flags
= ubd_dev
->openflags
;
634 err
= open_ubd_file(ubd_dev
->cow
.file
, &flags
, ubd_dev
->shared
, NULL
,
635 NULL
, NULL
, NULL
, NULL
);
636 if(err
< 0) goto error
;
637 ubd_dev
->cow
.fd
= err
;
641 os_close_file(ubd_dev
->fd
);
645 static void ubd_device_release(struct device
*dev
)
647 struct ubd
*ubd_dev
= dev
->driver_data
;
649 blk_cleanup_queue(ubd_dev
->queue
);
650 *ubd_dev
= ((struct ubd
) DEFAULT_UBD
);
653 static int ubd_disk_register(int major
, u64 size
, int unit
,
654 struct gendisk
**disk_out
)
656 struct gendisk
*disk
;
658 disk
= alloc_disk(1 << UBD_SHIFT
);
663 disk
->first_minor
= unit
<< UBD_SHIFT
;
664 disk
->fops
= &ubd_blops
;
665 set_capacity(disk
, size
/ 512);
666 if(major
== MAJOR_NR
)
667 sprintf(disk
->disk_name
, "ubd%c", 'a' + unit
);
669 sprintf(disk
->disk_name
, "ubd_fake%d", unit
);
671 /* sysfs register (not for ide fake devices) */
672 if (major
== MAJOR_NR
) {
673 ubd_devs
[unit
].pdev
.id
= unit
;
674 ubd_devs
[unit
].pdev
.name
= DRIVER_NAME
;
675 ubd_devs
[unit
].pdev
.dev
.release
= ubd_device_release
;
676 ubd_devs
[unit
].pdev
.dev
.driver_data
= &ubd_devs
[unit
];
677 platform_device_register(&ubd_devs
[unit
].pdev
);
678 disk
->driverfs_dev
= &ubd_devs
[unit
].pdev
.dev
;
681 disk
->private_data
= &ubd_devs
[unit
];
682 disk
->queue
= ubd_devs
[unit
].queue
;
689 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9))
691 static int ubd_add(int n
, char **error_out
)
693 struct ubd
*ubd_dev
= &ubd_devs
[n
];
696 if(ubd_dev
->file
== NULL
)
699 err
= ubd_file_size(ubd_dev
, &ubd_dev
->size
);
701 *error_out
= "Couldn't determine size of device's file";
705 ubd_dev
->size
= ROUND_BLOCK(ubd_dev
->size
);
707 INIT_LIST_HEAD(&ubd_dev
->restart
);
708 sg_init_table(ubd_dev
->sg
, MAX_SG
);
711 ubd_dev
->queue
= blk_init_queue(do_ubd_request
, &ubd_dev
->lock
);
712 if (ubd_dev
->queue
== NULL
) {
713 *error_out
= "Failed to initialize device queue";
716 ubd_dev
->queue
->queuedata
= ubd_dev
;
718 blk_queue_max_hw_segments(ubd_dev
->queue
, MAX_SG
);
719 err
= ubd_disk_register(MAJOR_NR
, ubd_dev
->size
, n
, &ubd_gendisk
[n
]);
721 *error_out
= "Failed to register device";
725 if(fake_major
!= MAJOR_NR
)
726 ubd_disk_register(fake_major
, ubd_dev
->size
, n
,
729 /* perhaps this should also be under the "if (fake_major)" above */
730 /* using the fake_disk->disk_name and also the fakehd_set name */
732 make_ide_entries(ubd_gendisk
[n
]->disk_name
);
739 blk_cleanup_queue(ubd_dev
->queue
);
743 static int ubd_config(char *str
, char **error_out
)
747 /* This string is possibly broken up and stored, so it's only
748 * freed if ubd_setup_common fails, or if only general options
751 str
= kstrdup(str
, GFP_KERNEL
);
753 *error_out
= "Failed to allocate memory";
757 ret
= ubd_setup_common(str
, &n
, error_out
);
766 mutex_lock(&ubd_lock
);
767 ret
= ubd_add(n
, error_out
);
769 ubd_devs
[n
].file
= NULL
;
770 mutex_unlock(&ubd_lock
);
780 static int ubd_get_config(char *name
, char *str
, int size
, char **error_out
)
785 n
= parse_unit(&name
);
786 if((n
>= MAX_DEV
) || (n
< 0)){
787 *error_out
= "ubd_get_config : device number out of range";
791 ubd_dev
= &ubd_devs
[n
];
792 mutex_lock(&ubd_lock
);
794 if(ubd_dev
->file
== NULL
){
795 CONFIG_CHUNK(str
, size
, len
, "", 1);
799 CONFIG_CHUNK(str
, size
, len
, ubd_dev
->file
, 0);
801 if(ubd_dev
->cow
.file
!= NULL
){
802 CONFIG_CHUNK(str
, size
, len
, ",", 0);
803 CONFIG_CHUNK(str
, size
, len
, ubd_dev
->cow
.file
, 1);
805 else CONFIG_CHUNK(str
, size
, len
, "", 1);
808 mutex_unlock(&ubd_lock
);
812 static int ubd_id(char **str
, int *start_out
, int *end_out
)
818 *end_out
= MAX_DEV
- 1;
822 static int ubd_remove(int n
, char **error_out
)
824 struct gendisk
*disk
= ubd_gendisk
[n
];
828 mutex_lock(&ubd_lock
);
830 ubd_dev
= &ubd_devs
[n
];
832 if(ubd_dev
->file
== NULL
)
835 /* you cannot remove a open disk */
837 if(ubd_dev
->count
> 0)
840 ubd_gendisk
[n
] = NULL
;
846 if(fake_gendisk
[n
] != NULL
){
847 del_gendisk(fake_gendisk
[n
]);
848 put_disk(fake_gendisk
[n
]);
849 fake_gendisk
[n
] = NULL
;
853 platform_device_unregister(&ubd_dev
->pdev
);
855 mutex_unlock(&ubd_lock
);
859 /* All these are called by mconsole in process context and without
860 * ubd-specific locks. The structure itself is const except for .list.
862 static struct mc_device ubd_mc
= {
863 .list
= LIST_HEAD_INIT(ubd_mc
.list
),
865 .config
= ubd_config
,
866 .get_config
= ubd_get_config
,
868 .remove
= ubd_remove
,
871 static int __init
ubd_mc_init(void)
873 mconsole_register_dev(&ubd_mc
);
877 __initcall(ubd_mc_init
);
879 static int __init
ubd0_init(void)
881 struct ubd
*ubd_dev
= &ubd_devs
[0];
883 mutex_lock(&ubd_lock
);
884 if(ubd_dev
->file
== NULL
)
885 ubd_dev
->file
= "root_fs";
886 mutex_unlock(&ubd_lock
);
891 __initcall(ubd0_init
);
893 /* Used in ubd_init, which is an initcall */
894 static struct platform_driver ubd_driver
= {
900 static int __init
ubd_init(void)
905 if (register_blkdev(MAJOR_NR
, "ubd"))
908 if (fake_major
!= MAJOR_NR
) {
909 char name
[sizeof("ubd_nnn\0")];
911 snprintf(name
, sizeof(name
), "ubd_%d", fake_major
);
912 if (register_blkdev(fake_major
, "ubd"))
915 platform_driver_register(&ubd_driver
);
916 mutex_lock(&ubd_lock
);
917 for (i
= 0; i
< MAX_DEV
; i
++){
918 err
= ubd_add(i
, &error
);
920 printk(KERN_ERR
"Failed to initialize ubd device %d :"
923 mutex_unlock(&ubd_lock
);
927 late_initcall(ubd_init
);
929 static int __init
ubd_driver_init(void){
933 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
934 if(global_openflags
.s
){
935 printk(KERN_INFO
"ubd: Synchronous mode\n");
936 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
937 * enough. So use anyway the io thread. */
939 stack
= alloc_stack(0, 0);
940 io_pid
= start_io_thread(stack
+ PAGE_SIZE
- sizeof(void *),
944 "ubd : Failed to start I/O thread (errno = %d) - "
945 "falling back to synchronous I/O\n", -io_pid
);
949 err
= um_request_irq(UBD_IRQ
, thread_fd
, IRQ_READ
, ubd_intr
,
950 IRQF_DISABLED
, "ubd", ubd_devs
);
952 printk(KERN_ERR
"um_request_irq failed - errno = %d\n", -err
);
956 device_initcall(ubd_driver_init
);
958 static int ubd_open(struct inode
*inode
, struct file
*filp
)
960 struct gendisk
*disk
= inode
->i_bdev
->bd_disk
;
961 struct ubd
*ubd_dev
= disk
->private_data
;
964 if(ubd_dev
->count
== 0){
965 err
= ubd_open_dev(ubd_dev
);
967 printk(KERN_ERR
"%s: Can't open \"%s\": errno = %d\n",
968 disk
->disk_name
, ubd_dev
->file
, -err
);
973 set_disk_ro(disk
, !ubd_dev
->openflags
.w
);
975 /* This should no more be needed. And it didn't work anyway to exclude
976 * read-write remounting of filesystems.*/
977 /*if((filp->f_mode & FMODE_WRITE) && !ubd_dev->openflags.w){
978 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
985 static int ubd_release(struct inode
* inode
, struct file
* file
)
987 struct gendisk
*disk
= inode
->i_bdev
->bd_disk
;
988 struct ubd
*ubd_dev
= disk
->private_data
;
990 if(--ubd_dev
->count
== 0)
991 ubd_close_dev(ubd_dev
);
995 static void cowify_bitmap(__u64 io_offset
, int length
, unsigned long *cow_mask
,
996 __u64
*cow_offset
, unsigned long *bitmap
,
997 __u64 bitmap_offset
, unsigned long *bitmap_words
,
1000 __u64 sector
= io_offset
>> 9;
1001 int i
, update_bitmap
= 0;
1003 for(i
= 0; i
< length
>> 9; i
++){
1004 if(cow_mask
!= NULL
)
1005 ubd_set_bit(i
, (unsigned char *) cow_mask
);
1006 if(ubd_test_bit(sector
+ i
, (unsigned char *) bitmap
))
1010 ubd_set_bit(sector
+ i
, (unsigned char *) bitmap
);
1016 *cow_offset
= sector
/ (sizeof(unsigned long) * 8);
1018 /* This takes care of the case where we're exactly at the end of the
1019 * device, and *cow_offset + 1 is off the end. So, just back it up
1020 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
1021 * for the original diagnosis.
1023 if(*cow_offset
== ((bitmap_len
+ sizeof(unsigned long) - 1) /
1024 sizeof(unsigned long) - 1))
1027 bitmap_words
[0] = bitmap
[*cow_offset
];
1028 bitmap_words
[1] = bitmap
[*cow_offset
+ 1];
1030 *cow_offset
*= sizeof(unsigned long);
1031 *cow_offset
+= bitmap_offset
;
1034 static void cowify_req(struct io_thread_req
*req
, unsigned long *bitmap
,
1035 __u64 bitmap_offset
, __u64 bitmap_len
)
1037 __u64 sector
= req
->offset
>> 9;
1040 if(req
->length
> (sizeof(req
->sector_mask
) * 8) << 9)
1041 panic("Operation too long");
1043 if(req
->op
== UBD_READ
) {
1044 for(i
= 0; i
< req
->length
>> 9; i
++){
1045 if(ubd_test_bit(sector
+ i
, (unsigned char *) bitmap
))
1046 ubd_set_bit(i
, (unsigned char *)
1050 else cowify_bitmap(req
->offset
, req
->length
, &req
->sector_mask
,
1051 &req
->cow_offset
, bitmap
, bitmap_offset
,
1052 req
->bitmap_words
, bitmap_len
);
1055 /* Called with dev->lock held */
1056 static void prepare_request(struct request
*req
, struct io_thread_req
*io_req
,
1057 unsigned long long offset
, int page_offset
,
1058 int len
, struct page
*page
)
1060 struct gendisk
*disk
= req
->rq_disk
;
1061 struct ubd
*ubd_dev
= disk
->private_data
;
1064 io_req
->fds
[0] = (ubd_dev
->cow
.file
!= NULL
) ? ubd_dev
->cow
.fd
:
1066 io_req
->fds
[1] = ubd_dev
->fd
;
1067 io_req
->cow_offset
= -1;
1068 io_req
->offset
= offset
;
1069 io_req
->length
= len
;
1071 io_req
->sector_mask
= 0;
1073 io_req
->op
= (rq_data_dir(req
) == READ
) ? UBD_READ
: UBD_WRITE
;
1074 io_req
->offsets
[0] = 0;
1075 io_req
->offsets
[1] = ubd_dev
->cow
.data_offset
;
1076 io_req
->buffer
= page_address(page
) + page_offset
;
1077 io_req
->sectorsize
= 1 << 9;
1079 if(ubd_dev
->cow
.file
!= NULL
)
1080 cowify_req(io_req
, ubd_dev
->cow
.bitmap
,
1081 ubd_dev
->cow
.bitmap_offset
, ubd_dev
->cow
.bitmap_len
);
1085 /* Called with dev->lock held */
1086 static void do_ubd_request(struct request_queue
*q
)
1088 struct io_thread_req
*io_req
;
1089 struct request
*req
;
1090 int n
, last_sectors
;
1093 struct ubd
*dev
= q
->queuedata
;
1094 if(dev
->end_sg
== 0){
1095 struct request
*req
= elv_next_request(q
);
1100 blkdev_dequeue_request(req
);
1102 dev
->end_sg
= blk_rq_map_sg(q
, req
, dev
->sg
);
1107 while(dev
->start_sg
< dev
->end_sg
){
1108 struct scatterlist
*sg
= &dev
->sg
[dev
->start_sg
];
1110 req
->sector
+= last_sectors
;
1111 io_req
= kmalloc(sizeof(struct io_thread_req
),
1114 if(list_empty(&dev
->restart
))
1115 list_add(&dev
->restart
, &restart
);
1118 prepare_request(req
, io_req
,
1119 (unsigned long long) req
->sector
<< 9,
1120 sg
->offset
, sg
->length
, sg_page(sg
));
1122 last_sectors
= sg
->length
>> 9;
1123 n
= os_write_file(thread_fd
, &io_req
,
1124 sizeof(struct io_thread_req
*));
1125 if(n
!= sizeof(struct io_thread_req
*)){
1127 printk("write to io thread failed, "
1128 "errno = %d\n", -n
);
1129 else if(list_empty(&dev
->restart
))
1130 list_add(&dev
->restart
, &restart
);
1137 dev
->request
= NULL
;
1141 static int ubd_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
1143 struct ubd
*ubd_dev
= bdev
->bd_disk
->private_data
;
1147 geo
->cylinders
= ubd_dev
->size
/ (128 * 32 * 512);
1151 static int ubd_ioctl(struct inode
* inode
, struct file
* file
,
1152 unsigned int cmd
, unsigned long arg
)
1154 struct ubd
*ubd_dev
= inode
->i_bdev
->bd_disk
->private_data
;
1155 struct hd_driveid ubd_id
= {
1162 struct cdrom_volctrl volume
;
1163 case HDIO_GET_IDENTITY
:
1164 ubd_id
.cyls
= ubd_dev
->size
/ (128 * 32 * 512);
1165 if(copy_to_user((char __user
*) arg
, (char *) &ubd_id
,
1171 if(copy_from_user(&volume
, (char __user
*) arg
, sizeof(volume
)))
1173 volume
.channel0
= 255;
1174 volume
.channel1
= 255;
1175 volume
.channel2
= 255;
1176 volume
.channel3
= 255;
1177 if(copy_to_user((char __user
*) arg
, &volume
, sizeof(volume
)))
1184 static int path_requires_switch(char *from_cmdline
, char *from_cow
, char *cow
)
1186 struct uml_stat buf1
, buf2
;
1189 if(from_cmdline
== NULL
)
1191 if(!strcmp(from_cmdline
, from_cow
))
1194 err
= os_stat_file(from_cmdline
, &buf1
);
1196 printk("Couldn't stat '%s', err = %d\n", from_cmdline
, -err
);
1199 err
= os_stat_file(from_cow
, &buf2
);
1201 printk("Couldn't stat '%s', err = %d\n", from_cow
, -err
);
1204 if((buf1
.ust_dev
== buf2
.ust_dev
) && (buf1
.ust_ino
== buf2
.ust_ino
))
1207 printk("Backing file mismatch - \"%s\" requested,\n"
1208 "\"%s\" specified in COW header of \"%s\"\n",
1209 from_cmdline
, from_cow
, cow
);
1213 static int backing_file_mismatch(char *file
, __u64 size
, time_t mtime
)
1215 unsigned long modtime
;
1216 unsigned long long actual
;
1219 err
= os_file_modtime(file
, &modtime
);
1221 printk("Failed to get modification time of backing file "
1222 "\"%s\", err = %d\n", file
, -err
);
1226 err
= os_file_size(file
, &actual
);
1228 printk("Failed to get size of backing file \"%s\", "
1229 "err = %d\n", file
, -err
);
1234 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
1236 printk("Size mismatch (%llu vs %llu) of COW header vs backing "
1237 "file\n", (unsigned long long) size
, actual
);
1240 if(modtime
!= mtime
){
1241 printk("mtime mismatch (%ld vs %ld) of COW header vs backing "
1242 "file\n", mtime
, modtime
);
1248 int read_cow_bitmap(int fd
, void *buf
, int offset
, int len
)
1252 err
= os_seek_file(fd
, offset
);
1256 err
= os_read_file(fd
, buf
, len
);
1263 int open_ubd_file(char *file
, struct openflags
*openflags
, int shared
,
1264 char **backing_file_out
, int *bitmap_offset_out
,
1265 unsigned long *bitmap_len_out
, int *data_offset_out
,
1266 int *create_cow_out
)
1269 unsigned long long size
;
1270 __u32 version
, align
;
1272 int fd
, err
, sectorsize
, asked_switch
, mode
= 0644;
1274 fd
= os_open_file(file
, *openflags
, mode
);
1276 if ((fd
== -ENOENT
) && (create_cow_out
!= NULL
))
1277 *create_cow_out
= 1;
1278 if (!openflags
->w
||
1279 ((fd
!= -EROFS
) && (fd
!= -EACCES
)))
1282 fd
= os_open_file(file
, *openflags
, mode
);
1288 printk("Not locking \"%s\" on the host\n", file
);
1290 err
= os_lock_file(fd
, openflags
->w
);
1292 printk("Failed to lock '%s', err = %d\n", file
, -err
);
1297 /* Successful return case! */
1298 if(backing_file_out
== NULL
)
1301 err
= read_cow_header(file_reader
, &fd
, &version
, &backing_file
, &mtime
,
1302 &size
, §orsize
, &align
, bitmap_offset_out
);
1303 if(err
&& (*backing_file_out
!= NULL
)){
1304 printk("Failed to read COW header from COW file \"%s\", "
1305 "errno = %d\n", file
, -err
);
1311 asked_switch
= path_requires_switch(*backing_file_out
, backing_file
, file
);
1313 /* Allow switching only if no mismatch. */
1314 if (asked_switch
&& !backing_file_mismatch(*backing_file_out
, size
, mtime
)) {
1315 printk("Switching backing file to '%s'\n", *backing_file_out
);
1316 err
= write_cow_header(file
, fd
, *backing_file_out
,
1317 sectorsize
, align
, &size
);
1319 printk("Switch failed, errno = %d\n", -err
);
1323 *backing_file_out
= backing_file
;
1324 err
= backing_file_mismatch(*backing_file_out
, size
, mtime
);
1329 cow_sizes(version
, size
, sectorsize
, align
, *bitmap_offset_out
,
1330 bitmap_len_out
, data_offset_out
);
1338 int create_cow_file(char *cow_file
, char *backing_file
, struct openflags flags
,
1339 int sectorsize
, int alignment
, int *bitmap_offset_out
,
1340 unsigned long *bitmap_len_out
, int *data_offset_out
)
1345 fd
= open_ubd_file(cow_file
, &flags
, 0, NULL
, NULL
, NULL
, NULL
, NULL
);
1348 printk("Open of COW file '%s' failed, errno = %d\n", cow_file
,
1353 err
= init_cow_file(fd
, cow_file
, backing_file
, sectorsize
, alignment
,
1354 bitmap_offset_out
, bitmap_len_out
,
1363 static int update_bitmap(struct io_thread_req
*req
)
1367 if(req
->cow_offset
== -1)
1370 n
= os_seek_file(req
->fds
[1], req
->cow_offset
);
1372 printk("do_io - bitmap lseek failed : err = %d\n", -n
);
1376 n
= os_write_file(req
->fds
[1], &req
->bitmap_words
,
1377 sizeof(req
->bitmap_words
));
1378 if(n
!= sizeof(req
->bitmap_words
)){
1379 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n
,
1387 void do_io(struct io_thread_req
*req
)
1391 int n
, nsectors
, start
, end
, bit
;
1395 nsectors
= req
->length
/ req
->sectorsize
;
1398 bit
= ubd_test_bit(start
, (unsigned char *) &req
->sector_mask
);
1400 while((end
< nsectors
) &&
1401 (ubd_test_bit(end
, (unsigned char *)
1402 &req
->sector_mask
) == bit
))
1405 off
= req
->offset
+ req
->offsets
[bit
] +
1406 start
* req
->sectorsize
;
1407 len
= (end
- start
) * req
->sectorsize
;
1408 buf
= &req
->buffer
[start
* req
->sectorsize
];
1410 err
= os_seek_file(req
->fds
[bit
], off
);
1412 printk("do_io - lseek failed : err = %d\n", -err
);
1416 if(req
->op
== UBD_READ
){
1421 n
= os_read_file(req
->fds
[bit
], buf
, len
);
1423 printk("do_io - read failed, err = %d "
1424 "fd = %d\n", -n
, req
->fds
[bit
]);
1428 } while((n
< len
) && (n
!= 0));
1429 if (n
< len
) memset(&buf
[n
], 0, len
- n
);
1431 n
= os_write_file(req
->fds
[bit
], buf
, len
);
1433 printk("do_io - write failed err = %d "
1434 "fd = %d\n", -n
, req
->fds
[bit
]);
1441 } while(start
< nsectors
);
1443 req
->error
= update_bitmap(req
);
1446 /* Changed in start_io_thread, which is serialized by being called only
1447 * from ubd_init, which is an initcall.
1451 /* Only changed by the io thread. XXX: currently unused. */
1452 static int io_count
= 0;
1454 int io_thread(void *arg
)
1456 struct io_thread_req
*req
;
1459 ignore_sigwinch_sig();
1461 n
= os_read_file(kernel_fd
, &req
,
1462 sizeof(struct io_thread_req
*));
1463 if(n
!= sizeof(struct io_thread_req
*)){
1465 printk("io_thread - read failed, fd = %d, "
1466 "err = %d\n", kernel_fd
, -n
);
1468 printk("io_thread - short read, fd = %d, "
1469 "length = %d\n", kernel_fd
, n
);
1475 n
= os_write_file(kernel_fd
, &req
,
1476 sizeof(struct io_thread_req
*));
1477 if(n
!= sizeof(struct io_thread_req
*))
1478 printk("io_thread - write failed, fd = %d, err = %d\n",