MD: support initial bitmap creation in-kernel
Add bitmap support to the device-mapper specific metadata area.
This patch allows the creation of the bitmap metadata area upon
initial array creation via device-mapper.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 70bd738..f0769b3 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -534,6 +534,82 @@
kunmap_atomic(sb, KM_USER0);
}
+/*
+ * bitmap_new_disk_sb
+ * @bitmap
+ *
+ * This function is somewhat the reverse of bitmap_read_sb. bitmap_read_sb
+ * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
+ * This function verifies 'bitmap_info' and populates the on-disk bitmap
+ * structure, which is to be written to disk.
+ *
+ * Returns: 0 on success, -Exxx on error
+ */
+static int bitmap_new_disk_sb(struct bitmap *bitmap)
+{
+ bitmap_super_t *sb;
+ unsigned long chunksize, daemon_sleep, write_behind;
+ int err = -EINVAL;
+
+ bitmap->sb_page = alloc_page(GFP_KERNEL);
+ if (IS_ERR(bitmap->sb_page)) {
+ err = PTR_ERR(bitmap->sb_page);
+ bitmap->sb_page = NULL;
+ return err;
+ }
+ bitmap->sb_page->index = 0;
+
+ sb = kmap_atomic(bitmap->sb_page, KM_USER0);
+
+ sb->magic = cpu_to_le32(BITMAP_MAGIC);
+ sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
+
+ chunksize = bitmap->mddev->bitmap_info.chunksize;
+ BUG_ON(!chunksize);
+ if (!is_power_of_2(chunksize)) {
+ kunmap_atomic(sb, KM_USER0);
+ printk(KERN_ERR "bitmap chunksize not a power of 2\n");
+ return -EINVAL;
+ }
+ sb->chunksize = cpu_to_le32(chunksize);
+
+ daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
+ if (!daemon_sleep ||
+ (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
+ printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
+ daemon_sleep = 5 * HZ;
+ }
+ sb->daemon_sleep = cpu_to_le32(daemon_sleep);
+ bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
+
+ /*
+ * FIXME: write_behind for RAID1. If not specified, what
+ * is a good choice? We choose COUNTER_MAX / 2 arbitrarily.
+ */
+ write_behind = bitmap->mddev->bitmap_info.max_write_behind;
+ if (write_behind > COUNTER_MAX)
+ write_behind = COUNTER_MAX / 2;
+ sb->write_behind = cpu_to_le32(write_behind);
+ bitmap->mddev->bitmap_info.max_write_behind = write_behind;
+
+ /* keep the array size field of the bitmap superblock up to date */
+ sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
+
+ memcpy(sb->uuid, bitmap->mddev->uuid, 16);
+
+ bitmap->flags |= BITMAP_STALE;
+ sb->state |= cpu_to_le32(BITMAP_STALE);
+ bitmap->events_cleared = bitmap->mddev->events;
+ sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+
+ bitmap->flags |= BITMAP_HOSTENDIAN;
+ sb->version = cpu_to_le32(BITMAP_MAJOR_HOSTENDIAN);
+
+ kunmap_atomic(sb, KM_USER0);
+
+ return 0;
+}
+
/* read the superblock from the bitmap file and initialize some bitmap fields */
static int bitmap_read_sb(struct bitmap *bitmap)
{
@@ -1076,8 +1152,8 @@
}
printk(KERN_INFO "%s: bitmap initialized from disk: "
- "read %lu/%lu pages, set %lu bits\n",
- bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
+ "read %lu/%lu pages, set %lu of %lu bits\n",
+ bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, chunks);
return 0;
@@ -1728,9 +1804,16 @@
vfs_fsync(file, 1);
}
/* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
- if (!mddev->bitmap_info.external)
- err = bitmap_read_sb(bitmap);
- else {
+ if (!mddev->bitmap_info.external) {
+ /*
+ * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
+ * instructing us to create a new on-disk bitmap instance.
+ */
+ if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
+ err = bitmap_new_disk_sb(bitmap);
+ else
+ err = bitmap_read_sb(bitmap);
+ } else {
err = 0;
if (mddev->bitmap_info.chunksize == 0 ||
mddev->bitmap_info.daemon_sleep == 0)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 5e35535..1c26c7a 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -124,6 +124,7 @@
#define MD_CHANGE_DEVS 0 /* Some device status has changed */
#define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
#define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */
+#define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */
int suspended;
atomic_t active_io;