diff options
Diffstat (limited to 'arch/um/drivers/ubd_kern.c')
| -rw-r--r-- | arch/um/drivers/ubd_kern.c | 1607 |
1 files changed, 1607 insertions, 0 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c new file mode 100644 index 000000000..f4c1e6e97 --- /dev/null +++ b/arch/um/drivers/ubd_kern.c @@ -0,0 +1,1607 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Cambridge Greys Ltd + * Copyright (C) 2015-2016 Anton Ivanov (aivanov@brocade.com) + * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) + */ + +/* 2001-09-28...2002-04-17 + * Partition stuff by James_McMechan@hotmail.com + * old style ubd by setting UBD_SHIFT to 0 + * 2002-09-27...2002-10-18 massive tinkering for 2.5 + * partitions have changed in 2.5 + * 2003-01-29 more tinkering for 2.5.59-1 + * This should now address the sysfs problems and has + * the symlink for devfs to allow for booting with + * the common /dev/ubd/discX/... names rather than + * only /dev/ubdN/discN this version also has lots of + * clean ups preparing for ubd-many. + * James McMechan + */ + +#define UBD_SHIFT 4 + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/blkdev.h> +#include <linux/blk-mq.h> +#include <linux/ata.h> +#include <linux/hdreg.h> +#include <linux/major.h> +#include <linux/cdrom.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/ctype.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/platform_device.h> +#include <linux/scatterlist.h> +#include <asm/tlbflush.h> +#include <kern_util.h> +#include "mconsole_kern.h" +#include <init.h> +#include <irq_kern.h> +#include "ubd.h" +#include <os.h> +#include "cow.h" + +/* Max request size is determined by sector mask - 32K */ +#define UBD_MAX_REQUEST (8 * sizeof(long)) + +struct io_desc { + char *buffer; + unsigned long length; + unsigned long sector_mask; + unsigned long long cow_offset; + unsigned long bitmap_words[2]; +}; + +struct io_thread_req { + struct request *req; + int fds[2]; + unsigned long offsets[2]; + unsigned long long offset; + int sectorsize; + int error; + + int desc_cnt; + /* io_desc has to be the last element of the struct */ + struct io_desc io_desc[]; +}; + + +static struct io_thread_req * (*irq_req_buffer)[]; +static struct io_thread_req *irq_remainder; +static int irq_remainder_size; + +static struct io_thread_req * (*io_req_buffer)[]; +static struct io_thread_req *io_remainder; +static int io_remainder_size; + + + +static inline int ubd_test_bit(__u64 bit, unsigned char *data) +{ + __u64 n; + int bits, off; + + bits = sizeof(data[0]) * 8; + n = bit / bits; + off = bit % bits; + return (data[n] & (1 << off)) != 0; +} + +static inline void ubd_set_bit(__u64 bit, unsigned char *data) +{ + __u64 n; + int bits, off; + + bits = sizeof(data[0]) * 8; + n = bit / bits; + off = bit % bits; + data[n] |= (1 << off); +} +/*End stuff from ubd_user.h*/ + +#define DRIVER_NAME "uml-blkdev" + +static DEFINE_MUTEX(ubd_lock); +static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */ + +static int ubd_open(struct block_device *bdev, fmode_t mode); +static void ubd_release(struct gendisk *disk, fmode_t mode); +static int ubd_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg); +static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); + +#define MAX_DEV (16) + +static const struct block_device_operations ubd_blops = { + .owner = THIS_MODULE, + .open = ubd_open, + .release = ubd_release, + .ioctl = ubd_ioctl, + .compat_ioctl = blkdev_compat_ptr_ioctl, + .getgeo = ubd_getgeo, +}; + +/* Protected by ubd_lock */ +static struct gendisk *ubd_gendisk[MAX_DEV]; + +#ifdef CONFIG_BLK_DEV_UBD_SYNC +#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ + .cl = 1 }) +#else +#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ + .cl = 1 }) +#endif +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; + int bitmap_offset; + int data_offset; +}; + +#define MAX_SG 64 + +struct ubd { + /* name (and fd, below) of the file opened for writing, either the + * backing or the cow file. */ + char *file; + char *serial; + int count; + int fd; + __u64 size; + struct openflags boot_openflags; + struct openflags openflags; + unsigned shared:1; + unsigned no_cow:1; + unsigned no_trim:1; + struct cow cow; + struct platform_device pdev; + struct request_queue *queue; + struct blk_mq_tag_set tag_set; + spinlock_t lock; +}; + +#define DEFAULT_COW { \ + .file = NULL, \ + .fd = -1, \ + .bitmap = NULL, \ + .bitmap_offset = 0, \ + .data_offset = 0, \ +} + +#define DEFAULT_UBD { \ + .file = NULL, \ + .serial = NULL, \ + .count = 0, \ + .fd = -1, \ + .size = -1, \ + .boot_openflags = OPEN_FLAGS, \ + .openflags = OPEN_FLAGS, \ + .no_cow = 0, \ + .no_trim = 0, \ + .shared = 0, \ + .cow = DEFAULT_COW, \ + .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \ +} + +/* Protected by ubd_lock */ +static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD }; + +static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd); + +static int fake_ide_setup(char *str) +{ + pr_warn("The fake_ide option has been removed\n"); + return 1; +} +__setup("fake_ide", fake_ide_setup); + +__uml_help(fake_ide_setup, +"fake_ide\n" +" Obsolete stub.\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, char **error_out) +{ + struct ubd *ubd_dev; + struct openflags flags = global_openflags; + char *file, *backing_file, *serial; + int n, err = 0, i; + + if(index_out) *index_out = -1; + n = *str; + if(n == '='){ + str++; + if(!strcmp(str, "sync")){ + global_openflags = of_sync(global_openflags); + return err; + } + + pr_warn("fake major not supported any more\n"); + return 0; + } + + n = parse_unit(&str); + if(n < 0){ + *error_out = "Couldn't parse device number"; + return -EINVAL; + } + if(n >= MAX_DEV){ + *error_out = "Device number out of range"; + return 1; + } + + err = -EBUSY; + mutex_lock(&ubd_lock); + + ubd_dev = &ubd_devs[n]; + if(ubd_dev->file != NULL){ + *error_out = "Device is already configured"; + goto out; + } + + if (index_out) + *index_out = n; + + err = -EINVAL; + for (i = 0; i < sizeof("rscdt="); 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 't': + ubd_dev->no_trim = 1; + break; + case '=': + str++; + goto break_loop; + default: + *error_out = "Expected '=' or flag letter " + "(r, s, c, t or d)"; + goto out; + } + str++; + } + + if (*str == '=') + *error_out = "Too many flags specified"; + else + *error_out = "Missing '='"; + goto out; + +break_loop: + file = strsep(&str, ",:"); + if (*file == '\0') + file = NULL; + + backing_file = strsep(&str, ",:"); + if (backing_file && *backing_file == '\0') + backing_file = NULL; + + serial = strsep(&str, ",:"); + if (serial && *serial == '\0') + serial = NULL; + + if (backing_file && ubd_dev->no_cow) { + *error_out = "Can't specify both 'd' and a cow file"; + goto out; + } + + err = 0; + ubd_dev->file = file; + ubd_dev->cow.file = backing_file; + ubd_dev->serial = serial; + ubd_dev->boot_openflags = flags; +out: + mutex_unlock(&ubd_lock); + return err; +} + +static int ubd_setup(char *str) +{ + char *error; + int err; + + err = ubd_setup_common(str, NULL, &error); + if(err) + printk(KERN_ERR "Failed to initialize device with \"%s\" : " + "%s\n", str, error); + return 1; +} + +__setup("ubd", ubd_setup); +__uml_help(ubd_setup, +"ubd<n><flags>=<filename>[(:|,)<filename2>][(:|,)<serial>]\n" +" This is used to associate a device with a file in the underlying\n" +" filesystem. When specifying two filenames, the first one is the\n" +" COW name and the second is the backing file name. As separator you can\n" +" use either a ':' or a ',': the first one allows writing things like;\n" +" ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" +" while with a ',' the shell would not expand the 2nd '~'.\n" +" When using only one filename, UML will detect whether to treat it like\n" +" a COW file or a backing file. To override this detection, add the 'd'\n" +" flag:\n" +" ubd0d=BackingFile\n" +" Usually, there is a filesystem in the file, but \n" +" that's not required. Swap devices containing swap files can be\n" +" specified like this. Also, a file which doesn't contain a\n" +" filesystem can have its contents read in the virtual \n" +" machine by running 'dd' on the device. <n> must be in the range\n" +" 0 to 7. Appending an 'r' to the number will cause that device\n" +" to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" +" an 's' will cause data to be written to disk on the host immediately.\n" +" 'c' will cause the device to be treated as being shared between multiple\n" +" UMLs and file locking will be turned off - this is appropriate for a\n" +" cluster filesystem and inappropriate at almost all other times.\n\n" +" 't' will disable trim/discard support on the device (enabled by default).\n\n" +" An optional device serial number can be exposed using the serial parameter\n" +" on the cmdline which is exposed as a sysfs entry. This is particularly\n" +" useful when a unique number should be given to the device. Note when\n" +" specifying a label, the filename2 must be also presented. It can be\n" +" an empty string, in which case the backing file is not used:\n" +" ubd0=File,,Serial\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" +); + +/* Only changed by ubd_init, which is an initcall. */ +static int thread_fd = -1; + +/* Function to read several request pointers at a time +* handling fractional reads if (and as) needed +*/ + +static int bulk_req_safe_read( + int fd, + struct io_thread_req * (*request_buffer)[], + struct io_thread_req **remainder, + int *remainder_size, + int max_recs + ) +{ + int n = 0; + int res = 0; + + if (*remainder_size > 0) { + memmove( + (char *) request_buffer, + (char *) remainder, *remainder_size + ); + n = *remainder_size; + } + + res = os_read_file( + fd, + ((char *) request_buffer) + *remainder_size, + sizeof(struct io_thread_req *)*max_recs + - *remainder_size + ); + if (res > 0) { + n += res; + if ((n % sizeof(struct io_thread_req *)) > 0) { + /* + * Read somehow returned not a multiple of dword + * theoretically possible, but never observed in the + * wild, so read routine must be able to handle it + */ + *remainder_size = n % sizeof(struct io_thread_req *); + WARN(*remainder_size > 0, "UBD IPC read returned a partial result"); + memmove( + remainder, + ((char *) request_buffer) + + (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *), + *remainder_size + ); + n = n - *remainder_size; + } + } else { + n = res; + } + return n; +} + +/* Called without dev->lock held, and only in interrupt context. */ +static void ubd_handler(void) +{ + int n; + int count; + + while(1){ + n = bulk_req_safe_read( + thread_fd, + irq_req_buffer, + &irq_remainder, + &irq_remainder_size, + UBD_REQ_BUFFER_SIZE + ); + if (n < 0) { + if(n == -EAGAIN) + break; + printk(KERN_ERR "spurious interrupt in ubd_handler, " + "err = %d\n", -n); + return; + } + for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { + struct io_thread_req *io_req = (*irq_req_buffer)[count]; + + if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) { + blk_queue_max_discard_sectors(io_req->req->q, 0); + blk_queue_max_write_zeroes_sectors(io_req->req->q, 0); + } + blk_mq_end_request(io_req->req, io_req->error); + kfree(io_req); + } + } +} + +static irqreturn_t ubd_intr(int irq, void *dev) +{ + ubd_handler(); + return IRQ_HANDLED; +} + +/* Only changed by ubd_init, which is an initcall. */ +static int io_pid = -1; + +static void kill_io_thread(void) +{ + if(io_pid != -1) + os_kill_process(io_pid, 1); +} + +__uml_exitcall(kill_io_thread); + +static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) +{ + char *file; + int fd; + int err; + + __u32 version; + __u32 align; + char *backing_file; + time64_t mtime; + unsigned long long size; + int sector_size; + int bitmap_offset; + + if (ubd_dev->file && ubd_dev->cow.file) { + file = ubd_dev->cow.file; + + goto out; + } + + fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0); + if (fd < 0) + return fd; + + err = read_cow_header(file_reader, &fd, &version, &backing_file, \ + &mtime, &size, §or_size, &align, &bitmap_offset); + os_close_file(fd); + + if(err == -EINVAL) + file = ubd_dev->file; + else + file = backing_file; + +out: + return os_file_size(file, size_out); +} + +static int read_cow_bitmap(int fd, void *buf, int offset, int len) +{ + int err; + + err = os_pread_file(fd, buf, len, offset); + if (err < 0) + return err; + + return 0; +} + +static int backing_file_mismatch(char *file, __u64 size, time64_t mtime) +{ + time64_t modtime; + unsigned long long actual; + int err; + + err = os_file_modtime(file, &modtime); + if (err < 0) { + printk(KERN_ERR "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(KERN_ERR "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(KERN_ERR "Size mismatch (%llu vs %llu) of COW header " + "vs backing file\n", (unsigned long long) size, actual); + return -EINVAL; + } + if (modtime != mtime) { + printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs " + "backing file\n", mtime, modtime); + return -EINVAL; + } + return 0; +} + +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(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline, + -err); + return 0; + } + err = os_stat_file(from_cow, &buf2); + if (err < 0) { + printk(KERN_ERR "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(KERN_ERR "Backing file mismatch - \"%s\" requested, " + "\"%s\" specified in COW header of \"%s\"\n", + from_cmdline, from_cow, cow); + return 1; +} + +static 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) +{ + time64_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(KERN_INFO "Not locking \"%s\" on the host\n", file); + else { + err = os_lock_file(fd, openflags->w); + if (err < 0) { + printk(KERN_ERR "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(KERN_ERR "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(KERN_ERR "Switching backing file to '%s'\n", + *backing_file_out); + err = write_cow_header(file, fd, *backing_file_out, + sectorsize, align, &size); + if (err) { + printk(KERN_ERR "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; +} + +static 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(KERN_ERR "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 void ubd_close_dev(struct ubd *ubd_dev) +{ + os_close_file(ubd_dev->fd); + if(ubd_dev->cow.file == NULL) + return; + + os_close_file(ubd_dev->cow.fd); + vfree(ubd_dev->cow.bitmap); + ubd_dev->cow.bitmap = NULL; +} + +static int ubd_open_dev(struct ubd *ubd_dev) +{ + struct openflags flags; + char **back_ptr; + int err, create_cow, *create_ptr; + int fd; + + ubd_dev->openflags = ubd_dev->boot_openflags; + create_cow = 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, SECTOR_SIZE, 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", ubd_dev->file, ubd_dev->cow.file); + } + } + + if(fd < 0){ + printk("Failed to open '%s', errno = %d\n", ubd_dev->file, + -fd); + return fd; + } + ubd_dev->fd = fd; + + if(ubd_dev->cow.file != NULL){ + blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long)); + + err = -ENOMEM; + ubd_dev->cow.bitmap = 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(ubd_dev->fd, ubd_dev->cow.bitmap, + ubd_dev->cow.bitmap_offset, + ubd_dev->cow.bitmap_len); + if(err < 0) + goto error; + + flags = ubd_dev->openflags; + flags.w = 0; + err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, + NULL, NULL, NULL, NULL); + if(err < 0) goto error; + ubd_dev->cow.fd = err; + } + if (ubd_dev->no_trim == 0) { + ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE; + blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST); + blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST); + } + blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue); + return 0; + error: + os_close_file(ubd_dev->fd); + return err; +} + +static void ubd_device_release(struct device *dev) +{ + struct ubd *ubd_dev = dev_get_drvdata(dev); + + blk_mq_free_tag_set(&ubd_dev->tag_set); + *ubd_dev = ((struct ubd) DEFAULT_UBD); +} + +static ssize_t serial_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + struct ubd *ubd_dev = disk->private_data; + + if (!ubd_dev) + return 0; + + return sprintf(buf, "%s", ubd_dev->serial); +} + +static DEVICE_ATTR_RO(serial); + +static struct attribute *ubd_attrs[] = { + &dev_attr_serial.attr, + NULL, +}; + +static umode_t ubd_attrs_are_visible(struct kobject *kobj, + struct attribute *a, int n) +{ + return a->mode; +} + +static const struct attribute_group ubd_attr_group = { + .attrs = ubd_attrs, + .is_visible = ubd_attrs_are_visible, +}; + +static const struct attribute_group *ubd_attr_groups[] = { + &ubd_attr_group, + NULL, +}; + +static int ubd_disk_register(int major, u64 size, int unit, + struct gendisk *disk) +{ + disk->major = major; + disk->first_minor = unit << UBD_SHIFT; + disk->minors = 1 << UBD_SHIFT; + disk->fops = &ubd_blops; + set_capacity(disk, size / 512); + sprintf(disk->disk_name, "ubd%c", 'a' + unit); + + ubd_devs[unit].pdev.id = unit; + ubd_devs[unit].pdev.name = DRIVER_NAME; + ubd_devs[unit].pdev.dev.release = ubd_device_release; + dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]); + platform_device_register(&ubd_devs[unit].pdev); + + disk->private_data = &ubd_devs[unit]; + disk->queue = ubd_devs[unit].queue; + return device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups); +} + +#define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE)) + +static const struct blk_mq_ops ubd_mq_ops = { + .queue_rq = ubd_queue_rq, +}; + +static int ubd_add(int n, char **error_out) +{ + struct ubd *ubd_dev = &ubd_devs[n]; + struct gendisk *disk; + int err = 0; + + if(ubd_dev->file == NULL) + goto out; + + err = ubd_file_size(ubd_dev, &ubd_dev->size); + if(err < 0){ + *error_out = "Couldn't determine size of device's file"; + goto out; + } + + ubd_dev->size = ROUND_BLOCK(ubd_dev->size); + + ubd_dev->tag_set.ops = &ubd_mq_ops; + ubd_dev->tag_set.queue_depth = 64; + ubd_dev->tag_set.numa_node = NUMA_NO_NODE; + ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; + ubd_dev->tag_set.driver_data = ubd_dev; + ubd_dev->tag_set.nr_hw_queues = 1; + + err = blk_mq_alloc_tag_set(&ubd_dev->tag_set); + if (err) + goto out; + + disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev); + if (IS_ERR(disk)) { + err = PTR_ERR(disk); + goto out_cleanup_tags; + } + ubd_dev->queue = disk->queue; + + blk_queue_write_cache(ubd_dev->queue, true, false); + blk_queue_max_segments(ubd_dev->queue, MAX_SG); + blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1); + err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, disk); + if (err) + goto out_cleanup_disk; + + ubd_gendisk[n] = disk; + return 0; + +out_cleanup_disk: + put_disk(disk); +out_cleanup_tags: + blk_mq_free_tag_set(&ubd_dev->tag_set); +out: + return err; +} + +static int ubd_config(char *str, char **error_out) +{ + int n, ret; + + /* This string is possibly broken up and stored, so it's only + * freed if ubd_setup_common fails, or if only general options + * were set. + */ + str = kstrdup(str, GFP_KERNEL); + if (str == NULL) { + *error_out = "Failed to allocate memory"; + return -ENOMEM; + } + + ret = ubd_setup_common(str, &n, error_out); + if (ret) + goto err_free; + + if (n == -1) { + ret = 0; + goto err_free; + } + + mutex_lock(&ubd_lock); + ret = ubd_add(n, error_out); + if (ret) + ubd_devs[n].file = NULL; + mutex_unlock(&ubd_lock); + +out: + return ret; + +err_free: + kfree(str); + goto out; +} + +static int ubd_get_config(char *name, char *str, int size, char **error_out) +{ + struct ubd *ubd_dev; + int n, len = 0; + + n = parse_unit(&name); + if((n >= MAX_DEV) || (n < 0)){ + *error_out = "ubd_get_config : device number out of range"; + return -1; + } + + ubd_dev = &ubd_devs[n]; + mutex_lock(&ubd_lock); + + if(ubd_dev->file == NULL){ + CONFIG_CHUNK(str, size, len, "", 1); + goto out; + } + + CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); + + 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, len, "", 1); + + out: + mutex_unlock(&ubd_lock); + return len; +} + +static int ubd_id(char **str, int *start_out, int *end_out) +{ + int n; + + n = parse_unit(str); + *start_out = 0; + *end_out = MAX_DEV - 1; + return n; +} + +static int ubd_remove(int n, char **error_out) +{ + struct gendisk *disk = ubd_gendisk[n]; + struct ubd *ubd_dev; + int err = -ENODEV; + + mutex_lock(&ubd_lock); + + 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; + + ubd_gendisk[n] = NULL; + if(disk != NULL){ + del_gendisk(disk); + put_disk(disk); + } + + err = 0; + platform_device_unregister(&ubd_dev->pdev); +out: + mutex_unlock(&ubd_lock); + return err; +} + +/* All these are called by mconsole in process context and without + * ubd-specific locks. The structure itself is const except for .list. + */ +static struct mc_device ubd_mc = { + .list = LIST_HEAD_INIT(ubd_mc.list), + .name = "ubd", + .config = ubd_config, + .get_config = ubd_get_config, + .id = ubd_id, + .remove = ubd_remove, +}; + +static int __init ubd_mc_init(void) +{ + mconsole_register_dev(&ubd_mc); + return 0; +} + +__initcall(ubd_mc_init); + +static int __init ubd0_init(void) +{ + struct ubd *ubd_dev = &ubd_devs[0]; + + mutex_lock(&ubd_lock); + if(ubd_dev->file == NULL) + ubd_dev->file = "root_fs"; + mutex_unlock(&ubd_lock); + + return 0; +} + +__initcall(ubd0_init); + +/* Used in ubd_init, which is an initcall */ +static struct platform_driver ubd_driver = { + .driver = { + .name = DRIVER_NAME, + }, +}; + +static int __init ubd_init(void) +{ + char *error; + int i, err; + + if (register_blkdev(UBD_MAJOR, "ubd")) + return -1; + + irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, + sizeof(struct io_thread_req *), + GFP_KERNEL + ); + irq_remainder = 0; + + if (irq_req_buffer == NULL) { + printk(KERN_ERR "Failed to initialize ubd buffering\n"); + return -1; + } + io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, + sizeof(struct io_thread_req *), + GFP_KERNEL + ); + + io_remainder = 0; + + if (io_req_buffer == NULL) { + printk(KERN_ERR "Failed to initialize ubd buffering\n"); + return -1; + } + platform_driver_register(&ubd_driver); + mutex_lock(&ubd_lock); + for (i = 0; i < MAX_DEV; i++){ + err = ubd_add(i, &error); + if(err) + printk(KERN_ERR "Failed to initialize ubd device %d :" + "%s\n", i, error); + } + mutex_unlock(&ubd_lock); + return 0; +} + +late_initcall(ubd_init); + +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"); + /* 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, &thread_fd); + if(io_pid < 0){ + printk(KERN_ERR + "ubd : Failed to start I/O thread (errno = %d) - " + "falling back to synchronous I/O\n", -io_pid); + io_pid = -1; + return 0; + } + err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, + 0, "ubd", ubd_devs); + if(err < 0) + printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); + return 0; +} + +device_initcall(ubd_driver_init); + +static int ubd_open(struct block_device *bdev, fmode_t mode) +{ + struct gendisk *disk = bdev->bd_disk; + struct ubd *ubd_dev = disk->private_data; + int err = 0; + + mutex_lock(&ubd_mutex); + 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, ubd_dev->file, -err); + goto out; + } + } + 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((mode & FMODE_WRITE) && !ubd_dev->openflags.w){ + if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); + err = -EROFS; + }*/ +out: + mutex_unlock(&ubd_mutex); + return err; +} + +static void ubd_release(struct gendisk *disk, fmode_t mode) +{ + struct ubd *ubd_dev = disk->private_data; + + mutex_lock(&ubd_mutex); + if(--ubd_dev->count == 0) + ubd_close_dev(ubd_dev); + mutex_unlock(&ubd_mutex); +} + +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 >> SECTOR_SHIFT; + int i, update_bitmap = 0; + + for (i = 0; i < length >> SECTOR_SHIFT; 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 == (DIV_ROUND_UP(bitmap_len, + 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, struct io_desc *segment, + unsigned long offset, unsigned long *bitmap, + __u64 bitmap_offset, __u64 bitmap_len) +{ + __u64 sector = offset >> SECTOR_SHIFT; + int i; + + if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT) + panic("Operation too long"); + + if (req_op(req->req) == REQ_OP_READ) { + for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) { + if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) + ubd_set_bit(i, (unsigned char *) + &segment->sector_mask); + } + } else { + cowify_bitmap(offset, segment->length, &segment->sector_mask, + &segment->cow_offset, bitmap, bitmap_offset, + segment->bitmap_words, bitmap_len); + } +} + +static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req, + struct request *req) +{ + struct bio_vec bvec; + struct req_iterator iter; + int i = 0; + unsigned long byte_offset = io_req->offset; + enum req_op op = req_op(req); + + if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) { + io_req->io_desc[0].buffer = NULL; + io_req->io_desc[0].length = blk_rq_bytes(req); + } else { + rq_for_each_segment(bvec, req, iter) { + BUG_ON(i >= io_req->desc_cnt); + + io_req->io_desc[i].buffer = bvec_virt(&bvec); + io_req->io_desc[i].length = bvec.bv_len; + i++; + } + } + + if (dev->cow.file) { + for (i = 0; i < io_req->desc_cnt; i++) { + cowify_req(io_req, &io_req->io_desc[i], byte_offset, + dev->cow.bitmap, dev->cow.bitmap_offset, + dev->cow.bitmap_len); + byte_offset += io_req->io_desc[i].length; + } + + } +} + +static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req, + int desc_cnt) +{ + struct io_thread_req *io_req; + int i; + + io_req = kmalloc(sizeof(*io_req) + + (desc_cnt * sizeof(struct io_desc)), + GFP_ATOMIC); + if (!io_req) + return NULL; + + io_req->req = req; + if (dev->cow.file) + io_req->fds[0] = dev->cow.fd; + else + io_req->fds[0] = dev->fd; + io_req->error = 0; + io_req->sectorsize = SECTOR_SIZE; + io_req->fds[1] = dev->fd; + io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT; + io_req->offsets[0] = 0; + io_req->offsets[1] = dev->cow.data_offset; + + for (i = 0 ; i < desc_cnt; i++) { + io_req->io_desc[i].sector_mask = 0; + io_req->io_desc[i].cow_offset = -1; + } + + return io_req; +} + +static int ubd_submit_request(struct ubd *dev, struct request *req) +{ + int segs = 0; + struct io_thread_req *io_req; + int ret; + enum req_op op = req_op(req); + + if (op == REQ_OP_FLUSH) + segs = 0; + else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) + segs = 1; + else + segs = blk_rq_nr_phys_segments(req); + + io_req = ubd_alloc_req(dev, req, segs); + if (!io_req) + return -ENOMEM; + + io_req->desc_cnt = segs; + if (segs) + ubd_map_req(dev, io_req, req); + + ret = os_write_file(thread_fd, &io_req, sizeof(io_req)); + if (ret != sizeof(io_req)) { + if (ret != -EAGAIN) + pr_err("write to io thread failed: %d\n", -ret); + kfree(io_req); + } + return ret; +} + +static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct ubd *ubd_dev = hctx->queue->queuedata; + struct request *req = bd->rq; + int ret = 0, res = BLK_STS_OK; + + blk_mq_start_request(req); + + spin_lock_irq(&ubd_dev->lock); + + switch (req_op(req)) { + case REQ_OP_FLUSH: + case REQ_OP_READ: + case REQ_OP_WRITE: + case REQ_OP_DISCARD: + case REQ_OP_WRITE_ZEROES: + ret = ubd_submit_request(ubd_dev, req); + break; + default: + WARN_ON_ONCE(1); + res = BLK_STS_NOTSUPP; + } + + spin_unlock_irq(&ubd_dev->lock); + + if (ret < 0) { + if (ret == -ENOMEM) + res = BLK_STS_RESOURCE; + else + res = BLK_STS_DEV_RESOURCE; + } + + return res; +} + +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 block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + struct ubd *ubd_dev = bdev->bd_disk->private_data; + u16 ubd_id[ATA_ID_WORDS]; + + switch (cmd) { + struct cdrom_volctrl volume; + case HDIO_GET_IDENTITY: + memset(&ubd_id, 0, ATA_ID_WORDS * 2); + ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512); + ubd_id[ATA_ID_HEADS] = 128; + ubd_id[ATA_ID_SECTORS] = 32; + if(copy_to_user((char __user *) arg, (char *) &ubd_id, + sizeof(ubd_id))) + return -EFAULT; + return 0; + + case CDROMVOLREAD: + if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) + return -EFAULT; + volume.channel0 = 255; + volume.channel1 = 255; + volume.channel2 = 255; + volume.channel3 = 255; + if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) + return -EFAULT; + return 0; + } + return -EINVAL; +} + +static int map_error(int error_code) +{ + switch (error_code) { + case 0: + return BLK_STS_OK; + case ENOSYS: + case EOPNOTSUPP: + return BLK_STS_NOTSUPP; + case ENOSPC: + return BLK_STS_NOSPC; + } + return BLK_STS_IOERR; +} + +/* + * Everything from here onwards *IS NOT PART OF THE KERNEL* + * + * The following functions are part of UML hypervisor code. + * All functions from here onwards are executed as a helper + * thread and are not allowed to execute any kernel functions. + * + * Any communication must occur strictly via shared memory and IPC. + * + * Do not add printks, locks, kernel memory operations, etc - it + * will result in unpredictable behaviour and/or crashes. + */ + +static int update_bitmap(struct io_thread_req *req, struct io_desc *segment) +{ + int n; + + if (segment->cow_offset == -1) + return map_error(0); + + n = os_pwrite_file(req->fds[1], &segment->bitmap_words, + sizeof(segment->bitmap_words), segment->cow_offset); + if (n != sizeof(segment->bitmap_words)) + return map_error(-n); + + return map_error(0); +} + +static void do_io(struct io_thread_req *req, struct io_desc *desc) +{ + char *buf = NULL; + unsigned long len; + int n, nsectors, start, end, bit; + __u64 off; + + /* FLUSH is really a special case, we cannot "case" it with others */ + + if (req_op(req->req) == REQ_OP_FLUSH) { + /* fds[0] is always either the rw image or our cow file */ + req->error = map_error(-os_sync_file(req->fds[0])); + return; + } + + nsectors = desc->length / req->sectorsize; + start = 0; + do { + bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask); + end = start; + while((end < nsectors) && + (ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit)) + end++; + + off = req->offset + req->offsets[bit] + + start * req->sectorsize; + len = (end - start) * req->sectorsize; + if (desc->buffer != NULL) + buf = &desc->buffer[start * req->sectorsize]; + + switch (req_op(req->req)) { + case REQ_OP_READ: + n = 0; + do { + buf = &buf[n]; + len -= n; + n = os_pread_file(req->fds[bit], buf, len, off); + if (n < 0) { + req->error = map_error(-n); + return; + } + } while((n < len) && (n != 0)); + if (n < len) memset(&buf[n], 0, len - n); + break; + case REQ_OP_WRITE: + n = os_pwrite_file(req->fds[bit], buf, len, off); + if(n != len){ + req->error = map_error(-n); + return; + } + break; + case REQ_OP_DISCARD: + n = os_falloc_punch(req->fds[bit], off, len); + if (n) { + req->error = map_error(-n); + return; + } + break; + case REQ_OP_WRITE_ZEROES: + n = os_falloc_zeroes(req->fds[bit], off, len); + if (n) { + req->error = map_error(-n); + return; + } + break; + default: + WARN_ON_ONCE(1); + req->error = BLK_STS_NOTSUPP; + return; + } + + start = end; + } while(start < nsectors); + + req->offset += len; + req->error = update_bitmap(req, desc); +} + +/* 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; + +int io_thread(void *arg) +{ + int n, count, written, res; + + os_fix_helper_signals(); + + while(1){ + n = bulk_req_safe_read( + kernel_fd, + io_req_buffer, + &io_remainder, + &io_remainder_size, + UBD_REQ_BUFFER_SIZE + ); + if (n <= 0) { + if (n == -EAGAIN) + ubd_read_poll(-1); + + continue; + } + + for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { + struct io_thread_req *req = (*io_req_buffer)[count]; + int i; + + io_count++; + for (i = 0; !req->error && i < req->desc_cnt; i++) + do_io(req, &(req->io_desc[i])); + + } + + written = 0; + + do { + res = os_write_file(kernel_fd, + ((char *) io_req_buffer) + written, + n - written); + if (res >= 0) { + written += res; + } + if (written < n) { + ubd_write_poll(-1); + } + } while (written < n); + } + + return 0; +} |