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-rw-r--r--arch/um/drivers/ubd_kern.c1599
1 files changed, 1599 insertions, 0 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
new file mode 100644
index 0000000000..50206feac5
--- /dev/null
+++ b/arch/um/drivers/ubd_kern.c
@@ -0,0 +1,1599 @@
+// 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 gendisk *disk, blk_mode_t mode);
+static void ubd_release(struct gendisk *disk);
+static int ubd_ioctl(struct block_device *bdev, blk_mode_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, &sector_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, &sectorsize, &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 gendisk *disk, blk_mode_t mode)
+{
+ 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);
+out:
+ mutex_unlock(&ubd_mutex);
+ return err;
+}
+
+static void ubd_release(struct gendisk *disk)
+{
+ 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, blk_mode_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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-07 23:04:07 +0000