separate partition format handling from generic code
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/block/partition-generic.c b/block/partition-generic.c
new file mode 100644
index 0000000..d06ec1c
--- /dev/null
+++ b/block/partition-generic.c
@@ -0,0 +1,537 @@
+/*
+ * Code extracted from drivers/block/genhd.c
+ * Copyright (C) 1991-1998 Linus Torvalds
+ * Re-organised Feb 1998 Russell King
+ *
+ * We now have independent partition support from the
+ * block drivers, which allows all the partition code to
+ * be grouped in one location, and it to be mostly self
+ * contained.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/kmod.h>
+#include <linux/ctype.h>
+#include <linux/genhd.h>
+#include <linux/blktrace_api.h>
+
+#include "partitions/check.h"
+
+#ifdef CONFIG_BLK_DEV_MD
+extern void md_autodetect_dev(dev_t dev);
+#endif
+
+/*
+ * disk_name() is used by partition check code and the genhd driver.
+ * It formats the devicename of the indicated disk into
+ * the supplied buffer (of size at least 32), and returns
+ * a pointer to that same buffer (for convenience).
+ */
+
+char *disk_name(struct gendisk *hd, int partno, char *buf)
+{
+ if (!partno)
+ snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
+ else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
+ snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
+ else
+ snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
+
+ return buf;
+}
+
+const char *bdevname(struct block_device *bdev, char *buf)
+{
+ return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
+}
+
+EXPORT_SYMBOL(bdevname);
+
+/*
+ * There's very little reason to use this, you should really
+ * have a struct block_device just about everywhere and use
+ * bdevname() instead.
+ */
+const char *__bdevname(dev_t dev, char *buffer)
+{
+ scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
+ MAJOR(dev), MINOR(dev));
+ return buffer;
+}
+
+EXPORT_SYMBOL(__bdevname);
+
+static ssize_t part_partition_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+
+ return sprintf(buf, "%d\n", p->partno);
+}
+
+static ssize_t part_start_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+
+ return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
+}
+
+ssize_t part_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
+}
+
+static ssize_t part_ro_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ return sprintf(buf, "%d\n", p->policy ? 1 : 0);
+}
+
+static ssize_t part_alignment_offset_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
+}
+
+static ssize_t part_discard_alignment_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ return sprintf(buf, "%u\n", p->discard_alignment);
+}
+
+ssize_t part_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ int cpu;
+
+ cpu = part_stat_lock();
+ part_round_stats(cpu, p);
+ part_stat_unlock();
+ return sprintf(buf,
+ "%8lu %8lu %8llu %8u "
+ "%8lu %8lu %8llu %8u "
+ "%8u %8u %8u"
+ "\n",
+ part_stat_read(p, ios[READ]),
+ part_stat_read(p, merges[READ]),
+ (unsigned long long)part_stat_read(p, sectors[READ]),
+ jiffies_to_msecs(part_stat_read(p, ticks[READ])),
+ part_stat_read(p, ios[WRITE]),
+ part_stat_read(p, merges[WRITE]),
+ (unsigned long long)part_stat_read(p, sectors[WRITE]),
+ jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
+ part_in_flight(p),
+ jiffies_to_msecs(part_stat_read(p, io_ticks)),
+ jiffies_to_msecs(part_stat_read(p, time_in_queue)));
+}
+
+ssize_t part_inflight_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+
+ return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
+ atomic_read(&p->in_flight[1]));
+}
+
+#ifdef CONFIG_FAIL_MAKE_REQUEST
+ssize_t part_fail_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+
+ return sprintf(buf, "%d\n", p->make_it_fail);
+}
+
+ssize_t part_fail_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ int i;
+
+ if (count > 0 && sscanf(buf, "%d", &i) > 0)
+ p->make_it_fail = (i == 0) ? 0 : 1;
+
+ return count;
+}
+#endif
+
+static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
+static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
+static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
+static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
+static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
+static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
+ NULL);
+static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
+static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
+#ifdef CONFIG_FAIL_MAKE_REQUEST
+static struct device_attribute dev_attr_fail =
+ __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
+#endif
+
+static struct attribute *part_attrs[] = {
+ &dev_attr_partition.attr,
+ &dev_attr_start.attr,
+ &dev_attr_size.attr,
+ &dev_attr_ro.attr,
+ &dev_attr_alignment_offset.attr,
+ &dev_attr_discard_alignment.attr,
+ &dev_attr_stat.attr,
+ &dev_attr_inflight.attr,
+#ifdef CONFIG_FAIL_MAKE_REQUEST
+ &dev_attr_fail.attr,
+#endif
+ NULL
+};
+
+static struct attribute_group part_attr_group = {
+ .attrs = part_attrs,
+};
+
+static const struct attribute_group *part_attr_groups[] = {
+ &part_attr_group,
+#ifdef CONFIG_BLK_DEV_IO_TRACE
+ &blk_trace_attr_group,
+#endif
+ NULL
+};
+
+static void part_release(struct device *dev)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ free_part_stats(p);
+ free_part_info(p);
+ kfree(p);
+}
+
+struct device_type part_type = {
+ .name = "partition",
+ .groups = part_attr_groups,
+ .release = part_release,
+};
+
+static void delete_partition_rcu_cb(struct rcu_head *head)
+{
+ struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
+
+ part->start_sect = 0;
+ part->nr_sects = 0;
+ part_stat_set_all(part, 0);
+ put_device(part_to_dev(part));
+}
+
+void __delete_partition(struct hd_struct *part)
+{
+ call_rcu(&part->rcu_head, delete_partition_rcu_cb);
+}
+
+void delete_partition(struct gendisk *disk, int partno)
+{
+ struct disk_part_tbl *ptbl = disk->part_tbl;
+ struct hd_struct *part;
+
+ if (partno >= ptbl->len)
+ return;
+
+ part = ptbl->part[partno];
+ if (!part)
+ return;
+
+ blk_free_devt(part_devt(part));
+ rcu_assign_pointer(ptbl->part[partno], NULL);
+ rcu_assign_pointer(ptbl->last_lookup, NULL);
+ kobject_put(part->holder_dir);
+ device_del(part_to_dev(part));
+
+ hd_struct_put(part);
+}
+
+static ssize_t whole_disk_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return 0;
+}
+static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
+ whole_disk_show, NULL);
+
+struct hd_struct *add_partition(struct gendisk *disk, int partno,
+ sector_t start, sector_t len, int flags,
+ struct partition_meta_info *info)
+{
+ struct hd_struct *p;
+ dev_t devt = MKDEV(0, 0);
+ struct device *ddev = disk_to_dev(disk);
+ struct device *pdev;
+ struct disk_part_tbl *ptbl;
+ const char *dname;
+ int err;
+
+ err = disk_expand_part_tbl(disk, partno);
+ if (err)
+ return ERR_PTR(err);
+ ptbl = disk->part_tbl;
+
+ if (ptbl->part[partno])
+ return ERR_PTR(-EBUSY);
+
+ p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return ERR_PTR(-EBUSY);
+
+ if (!init_part_stats(p)) {
+ err = -ENOMEM;
+ goto out_free;
+ }
+ pdev = part_to_dev(p);
+
+ p->start_sect = start;
+ p->alignment_offset =
+ queue_limit_alignment_offset(&disk->queue->limits, start);
+ p->discard_alignment =
+ queue_limit_discard_alignment(&disk->queue->limits, start);
+ p->nr_sects = len;
+ p->partno = partno;
+ p->policy = get_disk_ro(disk);
+
+ if (info) {
+ struct partition_meta_info *pinfo = alloc_part_info(disk);
+ if (!pinfo)
+ goto out_free_stats;
+ memcpy(pinfo, info, sizeof(*info));
+ p->info = pinfo;
+ }
+
+ dname = dev_name(ddev);
+ if (isdigit(dname[strlen(dname) - 1]))
+ dev_set_name(pdev, "%sp%d", dname, partno);
+ else
+ dev_set_name(pdev, "%s%d", dname, partno);
+
+ device_initialize(pdev);
+ pdev->class = &block_class;
+ pdev->type = &part_type;
+ pdev->parent = ddev;
+
+ err = blk_alloc_devt(p, &devt);
+ if (err)
+ goto out_free_info;
+ pdev->devt = devt;
+
+ /* delay uevent until 'holders' subdir is created */
+ dev_set_uevent_suppress(pdev, 1);
+ err = device_add(pdev);
+ if (err)
+ goto out_put;
+
+ err = -ENOMEM;
+ p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
+ if (!p->holder_dir)
+ goto out_del;
+
+ dev_set_uevent_suppress(pdev, 0);
+ if (flags & ADDPART_FLAG_WHOLEDISK) {
+ err = device_create_file(pdev, &dev_attr_whole_disk);
+ if (err)
+ goto out_del;
+ }
+
+ /* everything is up and running, commence */
+ rcu_assign_pointer(ptbl->part[partno], p);
+
+ /* suppress uevent if the disk suppresses it */
+ if (!dev_get_uevent_suppress(ddev))
+ kobject_uevent(&pdev->kobj, KOBJ_ADD);
+
+ hd_ref_init(p);
+ return p;
+
+out_free_info:
+ free_part_info(p);
+out_free_stats:
+ free_part_stats(p);
+out_free:
+ kfree(p);
+ return ERR_PTR(err);
+out_del:
+ kobject_put(p->holder_dir);
+ device_del(pdev);
+out_put:
+ put_device(pdev);
+ blk_free_devt(devt);
+ return ERR_PTR(err);
+}
+
+static bool disk_unlock_native_capacity(struct gendisk *disk)
+{
+ const struct block_device_operations *bdops = disk->fops;
+
+ if (bdops->unlock_native_capacity &&
+ !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
+ printk(KERN_CONT "enabling native capacity\n");
+ bdops->unlock_native_capacity(disk);
+ disk->flags |= GENHD_FL_NATIVE_CAPACITY;
+ return true;
+ } else {
+ printk(KERN_CONT "truncated\n");
+ return false;
+ }
+}
+
+int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+ struct parsed_partitions *state = NULL;
+ struct disk_part_iter piter;
+ struct hd_struct *part;
+ int p, highest, res;
+rescan:
+ if (state && !IS_ERR(state)) {
+ kfree(state);
+ state = NULL;
+ }
+
+ if (bdev->bd_part_count)
+ return -EBUSY;
+ res = invalidate_partition(disk, 0);
+ if (res)
+ return res;
+
+ disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
+ while ((part = disk_part_iter_next(&piter)))
+ delete_partition(disk, part->partno);
+ disk_part_iter_exit(&piter);
+
+ if (disk->fops->revalidate_disk)
+ disk->fops->revalidate_disk(disk);
+ check_disk_size_change(disk, bdev);
+ bdev->bd_invalidated = 0;
+ if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
+ return 0;
+ if (IS_ERR(state)) {
+ /*
+ * I/O error reading the partition table. If any
+ * partition code tried to read beyond EOD, retry
+ * after unlocking native capacity.
+ */
+ if (PTR_ERR(state) == -ENOSPC) {
+ printk(KERN_WARNING "%s: partition table beyond EOD, ",
+ disk->disk_name);
+ if (disk_unlock_native_capacity(disk))
+ goto rescan;
+ }
+ return -EIO;
+ }
+ /*
+ * If any partition code tried to read beyond EOD, try
+ * unlocking native capacity even if partition table is
+ * successfully read as we could be missing some partitions.
+ */
+ if (state->access_beyond_eod) {
+ printk(KERN_WARNING
+ "%s: partition table partially beyond EOD, ",
+ disk->disk_name);
+ if (disk_unlock_native_capacity(disk))
+ goto rescan;
+ }
+
+ /* tell userspace that the media / partition table may have changed */
+ kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+
+ /* Detect the highest partition number and preallocate
+ * disk->part_tbl. This is an optimization and not strictly
+ * necessary.
+ */
+ for (p = 1, highest = 0; p < state->limit; p++)
+ if (state->parts[p].size)
+ highest = p;
+
+ disk_expand_part_tbl(disk, highest);
+
+ /* add partitions */
+ for (p = 1; p < state->limit; p++) {
+ sector_t size, from;
+ struct partition_meta_info *info = NULL;
+
+ size = state->parts[p].size;
+ if (!size)
+ continue;
+
+ from = state->parts[p].from;
+ if (from >= get_capacity(disk)) {
+ printk(KERN_WARNING
+ "%s: p%d start %llu is beyond EOD, ",
+ disk->disk_name, p, (unsigned long long) from);
+ if (disk_unlock_native_capacity(disk))
+ goto rescan;
+ continue;
+ }
+
+ if (from + size > get_capacity(disk)) {
+ printk(KERN_WARNING
+ "%s: p%d size %llu extends beyond EOD, ",
+ disk->disk_name, p, (unsigned long long) size);
+
+ if (disk_unlock_native_capacity(disk)) {
+ /* free state and restart */
+ goto rescan;
+ } else {
+ /*
+ * we can not ignore partitions of broken tables
+ * created by for example camera firmware, but
+ * we limit them to the end of the disk to avoid
+ * creating invalid block devices
+ */
+ size = get_capacity(disk) - from;
+ }
+ }
+
+ if (state->parts[p].has_info)
+ info = &state->parts[p].info;
+ part = add_partition(disk, p, from, size,
+ state->parts[p].flags,
+ &state->parts[p].info);
+ if (IS_ERR(part)) {
+ printk(KERN_ERR " %s: p%d could not be added: %ld\n",
+ disk->disk_name, p, -PTR_ERR(part));
+ continue;
+ }
+#ifdef CONFIG_BLK_DEV_MD
+ if (state->parts[p].flags & ADDPART_FLAG_RAID)
+ md_autodetect_dev(part_to_dev(part)->devt);
+#endif
+ }
+ kfree(state);
+ return 0;
+}
+
+unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
+{
+ struct address_space *mapping = bdev->bd_inode->i_mapping;
+ struct page *page;
+
+ page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
+ NULL);
+ if (!IS_ERR(page)) {
+ if (PageError(page))
+ goto fail;
+ p->v = page;
+ return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
+fail:
+ page_cache_release(page);
+ }
+ p->v = NULL;
+ return NULL;
+}
+
+EXPORT_SYMBOL(read_dev_sector);