Add mirroring support across multiple drives

btrfsck.c

@@ -480,7 +480,6 @@ static int pick_next_pending(struct cache_tree *pending,
 	}
 	return ret;
 }
-static struct extent_buffer reada_buf;
 
 static int run_next_block(struct btrfs_root *root,
 			  struct block_info *bits,
@@ -503,7 +502,6 @@ static int run_next_block(struct btrfs_root *root,
 	struct cache_extent *cache;
 	int reada_bits;
 
-	u64 last_block = 0;
 	ret = pick_next_pending(pending, reada, nodes, *last, bits,
 				bits_nr, &reada_bits);
 	if (ret == 0) {
@@ -511,14 +509,9 @@ static int run_next_block(struct btrfs_root *root,
 	}
 	if (!reada_bits) {
 		for(i = 0; i < ret; i++) {
-			u64 offset;
 			insert_cache_extent(reada, bits[i].start,
 					    bits[i].size);
-			btrfs_map_bh_to_logical(root, &reada_buf,
-						bits[i].start);
-			offset = reada_buf.dev_bytenr;
-			last_block = bits[i].start;
-			readahead(reada_buf.fd, offset, bits[i].size);
+			readahead_tree_block(root, bits[i].start, bits[i].size);
 		}
 	}
 	*last = bits[0].start;

ctree.h

@@ -406,6 +406,7 @@ struct btrfs_csum_item {
 #define BTRFS_BLOCK_GROUP_SYSTEM   (1 << 1)
 #define BTRFS_BLOCK_GROUP_METADATA (1 << 2)
 #define BTRFS_BLOCK_GROUP_RAID0    (1 << 3)
+#define BTRFS_BLOCK_GROUP_RAID1    (1 << 4)
 
 struct btrfs_block_group_item {
 	__le64 used;

disk-io.c

@@ -18,6 +18,7 @@
 
 #define _XOPEN_SOURCE 600
 #define __USE_XOPEN2K
+#define _GNU_SOURCE 1
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
@@ -33,22 +34,6 @@
 #include "crc32c.h"
 #include "utils.h"
 
-int btrfs_map_bh_to_logical(struct btrfs_root *root, struct extent_buffer *buf,
-			    u64 logical)
-{
-	u64 physical;
-	u64 length;
-	struct btrfs_device *device;
-	int ret;
-
-	ret = btrfs_map_block(&root->fs_info->mapping_tree, logical, &physical,
-			      &length, &device);
-	BUG_ON(ret);
-	buf->fd = device->fd;
-	buf->dev_bytenr = physical;
-	return 0;
-}
-
 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
 {
 	if (buf->start != btrfs_header_bytenr(buf))
@@ -110,6 +95,28 @@ struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 
 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize)
 {
+	int ret;
+	int total_devs = 1;
+	int dev_nr;
+	struct extent_buffer *eb;
+	u64 physical;
+	u64 length;
+	struct btrfs_device *device;
+
+	eb = btrfs_find_tree_block(root, bytenr, blocksize);
+	if (eb && btrfs_buffer_uptodate(eb)) {
+		free_extent_buffer(eb);
+		return 0;
+	}
+
+	dev_nr = 0;
+	ret = btrfs_map_block(&root->fs_info->mapping_tree, READ, dev_nr,
+			      bytenr, &physical, &length, &device,
+			      &total_devs);
+	BUG_ON(ret);
+	device->total_ios++;
+	blocksize = min(blocksize, (u32)(64 * 1024));
+	readahead(device->fd, physical, blocksize);
 	return 0;
 }
 
@@ -117,35 +124,69 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 				     u32 blocksize)
 {
 	int ret;
+	int total_devs = 1;
+	int dev_nr;
 	struct extent_buffer *eb;
+	u64 physical;
+	u64 length;
+	struct btrfs_device *device;
 
 	eb = btrfs_find_create_tree_block(root, bytenr, blocksize);
 	if (!eb)
 		return NULL;
-	if (!btrfs_buffer_uptodate(eb)) {
-		btrfs_map_bh_to_logical(root, eb, eb->start);
-		ret = read_extent_from_disk(eb);
-		if (ret) {
-			free_extent_buffer(eb);
-			return NULL;
-		}
-		btrfs_set_buffer_uptodate(eb);
+
+	if (btrfs_buffer_uptodate(eb))
+		return eb;
+
+	dev_nr = 0;
+	ret = btrfs_map_block(&root->fs_info->mapping_tree, READ, dev_nr,
+			      eb->start, &physical, &length, &device,
+			      &total_devs);
+	BUG_ON(ret);
+	eb->fd = device->fd;
+	device->total_ios++;
+	eb->dev_bytenr = physical;
+	ret = read_extent_from_disk(eb);
+	if (ret) {
+		free_extent_buffer(eb);
+		return NULL;
 	}
+	btrfs_set_buffer_uptodate(eb);
 	return eb;
 }
 
 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		     struct extent_buffer *eb)
 {
+	int ret;
+	int total_devs = 1;
+	int dev_nr;
+	u64 physical;
+	u64 length;
+	struct btrfs_device *device;
+
 	if (check_tree_block(root, eb))
 		BUG();
 	if (!btrfs_buffer_uptodate(eb))
 		BUG();
 
 	btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
-	btrfs_map_bh_to_logical(root, eb, eb->start);
 	csum_tree_block(root, eb, 0);
-	return write_extent_to_disk(eb);
+
+	dev_nr = 0;
+	while(dev_nr < total_devs) {
+		ret = btrfs_map_block(&root->fs_info->mapping_tree, WRITE,
+				      dev_nr, eb->start, &physical, &length,
+				      &device, &total_devs);
+		BUG_ON(ret);
+		eb->fd = device->fd;
+		eb->dev_bytenr = physical;
+		dev_nr++;
+		device->total_ios++;
+		ret = write_extent_to_disk(eb);
+		BUG_ON(ret);
+	}
+	return 0;
 }
 
 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,

extent-tree.c

@@ -1620,8 +1620,12 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 	struct btrfs_key keys[2];
 	int extra_alloc_flags = 0;
 
-	if (btrfs_super_num_devices(&info->super_copy) > 1)
-		extra_alloc_flags = BTRFS_BLOCK_GROUP_RAID0;
+	if (0 && btrfs_super_num_devices(&info->super_copy) > 1) {
+		if (data)
+			extra_alloc_flags = BTRFS_BLOCK_GROUP_RAID0;
+		else
+			extra_alloc_flags = BTRFS_BLOCK_GROUP_RAID1;
+	}
 
 	if (data) {
 		data = BTRFS_BLOCK_GROUP_DATA | extra_alloc_flags;

kerncompat.h

@@ -25,6 +25,12 @@
 #include <endian.h>
 #include <byteswap.h>
 
+#ifndef READ
+#define READ 0
+#define WRITE 1
+#define READA 2
+#endif
+
 #define gfp_t int
 #define get_cpu_var(p) (p)
 #define __get_cpu_var(p) (p)

mkfs.c

@@ -163,6 +163,8 @@ int main(int ac, char **av)
 	char *file;
 	u64 block_count = 0;
 	u64 dev_block_count = 0;
+	u64 chunk_start;
+	u64 chunk_size;
 	int fd;
 	int first_fd;
 	int ret;
@@ -295,6 +297,29 @@ int main(int ac, char **av)
 		close(fd);
 		btrfs_register_one_device(file);
 	}
+
+	ret = btrfs_alloc_chunk(trans, root->fs_info->extent_root,
+				&chunk_start, &chunk_size,
+				BTRFS_BLOCK_GROUP_METADATA |
+				BTRFS_BLOCK_GROUP_RAID1);
+	BUG_ON(ret);
+	ret = btrfs_make_block_group(trans, root->fs_info->extent_root, 0,
+				     BTRFS_BLOCK_GROUP_METADATA |
+				     BTRFS_BLOCK_GROUP_RAID1,
+				     BTRFS_CHUNK_TREE_OBJECTID,
+				     chunk_start, chunk_size);
+	BUG_ON(ret);
+	ret = btrfs_alloc_chunk(trans, root->fs_info->extent_root,
+				&chunk_start, &chunk_size,
+				BTRFS_BLOCK_GROUP_DATA |
+				BTRFS_BLOCK_GROUP_RAID0);
+	BUG_ON(ret);
+	ret = btrfs_make_block_group(trans, root->fs_info->extent_root, 0,
+				     BTRFS_BLOCK_GROUP_DATA |
+				     BTRFS_BLOCK_GROUP_RAID0,
+				     BTRFS_CHUNK_TREE_OBJECTID,
+				     chunk_start, chunk_size);
+	BUG_ON(ret);
 	btrfs_commit_transaction(trans, root);
 	ret = close_ctree(root);
 	BUG_ON(ret);

utils.c

@@ -404,31 +404,40 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
 {
 	struct btrfs_super_block *disk_super;
 	struct btrfs_super_block *super = &root->fs_info->super_copy;
-	struct btrfs_device device;
+	struct btrfs_device *device;
 	struct btrfs_dev_item *dev_item;
 	char *buf;
 	u64 total_bytes;
 	u64 num_devs;
 	int ret;
 
-	buf = malloc(sectorsize);
+	device = kmalloc(sizeof(*device), GFP_NOFS);
+	if (!device)
+		return -ENOMEM;
+	buf = kmalloc(sectorsize, GFP_NOFS);
+	if (!buf) {
+		kfree(device);
+		return -ENOMEM;
+	}
 	BUG_ON(sizeof(*disk_super) > sectorsize);
 	memset(buf, 0, sectorsize);
 
 	disk_super = (struct btrfs_super_block *)buf;
 	dev_item = &disk_super->dev_item;
 
-	uuid_generate(device.uuid);
-	device.devid = 0;
-	device.type = 0;
-	device.io_width = io_width;
-	device.io_align = io_align;
-	device.sector_size = sectorsize;
-	device.fd = 0;
-	device.total_bytes = block_count;
-	device.bytes_used = 0;
+	uuid_generate(device->uuid);
+	device->devid = 0;
+	device->type = 0;
+	device->io_width = io_width;
+	device->io_align = io_align;
+	device->sector_size = sectorsize;
+	device->fd = 0;
+	device->total_bytes = block_count;
+	device->bytes_used = 0;
+	device->total_ios = 0;
+	device->dev_root = root->fs_info->dev_root;
 
-	ret = btrfs_add_device(trans, root, &device);
+	ret = btrfs_add_device(trans, root, device);
 	BUG_ON(ret);
 
 	total_bytes = btrfs_super_total_bytes(super) + block_count;
@@ -439,20 +448,21 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
 
 	memcpy(disk_super, super, sizeof(*disk_super));
 
-	printf("adding device id %llu\n", (unsigned long long)device.devid);
-	btrfs_set_stack_device_id(dev_item, device.devid);
-	btrfs_set_stack_device_type(dev_item, device.type);
-	btrfs_set_stack_device_io_align(dev_item, device.io_align);
-	btrfs_set_stack_device_io_width(dev_item, device.io_width);
-	btrfs_set_stack_device_sector_size(dev_item, device.sector_size);
-	btrfs_set_stack_device_total_bytes(dev_item, device.total_bytes);
-	btrfs_set_stack_device_bytes_used(dev_item, device.bytes_used);
-	memcpy(&dev_item->uuid, device.uuid, BTRFS_DEV_UUID_SIZE);
+	printf("adding device id %llu\n", (unsigned long long)device->devid);
+	btrfs_set_stack_device_id(dev_item, device->devid);
+	btrfs_set_stack_device_type(dev_item, device->type);
+	btrfs_set_stack_device_io_align(dev_item, device->io_align);
+	btrfs_set_stack_device_io_width(dev_item, device->io_width);
+	btrfs_set_stack_device_sector_size(dev_item, device->sector_size);
+	btrfs_set_stack_device_total_bytes(dev_item, device->total_bytes);
+	btrfs_set_stack_device_bytes_used(dev_item, device->bytes_used);
+	memcpy(&dev_item->uuid, device->uuid, BTRFS_DEV_UUID_SIZE);
 
 	ret = pwrite(fd, buf, sectorsize, BTRFS_SUPER_INFO_OFFSET);
 	BUG_ON(ret != sectorsize);
 
-	free(buf);
+	kfree(buf);
+	list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
 	return 0;
 }
 

volumes.c

@@ -232,6 +232,10 @@ static int find_free_dev_extent(struct btrfs_trans_handle *trans,
 
 	/* FIXME use last free of some kind */
 
+	/* we don't want to overwrite the superblock on the drive,
+	 * so we make sure to start at an offset of at least 1MB
+	 */
+	search_start = max((u64)1024 * 1024, search_start);
 	key.objectid = device->devid;
 	key.offset = search_start;
 	key.type = BTRFS_DEV_EXTENT_KEY;
@@ -578,12 +582,15 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	if (list_empty(dev_list))
 		return -ENOSPC;
 
-	if (type & BTRFS_BLOCK_GROUP_RAID0)
+	if (type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1)) {
+		calc_size = 1024 * 1024 * 1024;
+	}
+	if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
+		num_stripes = min_t(u64, 2,
+				  btrfs_super_num_devices(&info->super_copy));
+	}
+	if (type & (BTRFS_BLOCK_GROUP_RAID0))
 		num_stripes = btrfs_super_num_devices(&info->super_copy);
-	if (type & BTRFS_BLOCK_GROUP_DATA)
-		stripe_len = 64 * 1024;
-	if (type & (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_SYSTEM))
-		stripe_len = 32 * 1024;
 again:
 	INIT_LIST_HEAD(&private_devs);
 	cur = dev_list->next;
@@ -628,7 +635,11 @@ again:
 
 	stripes = &chunk->stripe;
 
-	*num_bytes = calc_size * num_stripes;
+	if (type & BTRFS_BLOCK_GROUP_RAID1)
+		*num_bytes = calc_size;
+	else
+		*num_bytes = calc_size * num_stripes;
+
 	index = 0;
 	while(index < num_stripes) {
 		BUG_ON(list_empty(&private_devs));
@@ -695,9 +706,9 @@ void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
 	cache_tree_init(&tree->cache_tree);
 }
 
-int btrfs_map_block(struct btrfs_mapping_tree *map_tree,
-		    u64 logical, u64 *phys, u64 *length,
-		    struct btrfs_device **dev)
+int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
+		    int dev_nr, u64 logical, u64 *phys, u64 *length,
+		    struct btrfs_device **dev, int *total_devs)
 {
 	struct cache_extent *ce;
 	struct map_lookup *map;
@@ -725,20 +736,28 @@ int btrfs_map_block(struct btrfs_mapping_tree *map_tree,
 	/* stripe_offset is the offset of this block in its stripe*/
 	stripe_offset = offset - stripe_offset;
 
-	/*
-	 * after this do_div call, stripe_nr is the number of stripes
-	 * on this device we have to walk to find the data, and
-	 * stripe_index is the number of our device in the stripe array
-	 */
-	stripe_index = stripe_nr % map->num_stripes;
-	stripe_nr = stripe_nr / map->num_stripes;
-
+	if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
+		stripe_index = dev_nr;
+		if (rw == WRITE)
+			*total_devs = map->num_stripes;
+		else {
+			stripe_index = stripe_nr % map->num_stripes;
+			*total_devs = 1;
+		}
+	} else {
+		/*
+		 * after this do_div call, stripe_nr is the number of stripes
+		 * on this device we have to walk to find the data, and
+		 * stripe_index is the number of our device in the stripe array
+		 */
+		stripe_index = stripe_nr % map->num_stripes;
+		stripe_nr = stripe_nr / map->num_stripes;
+	}
 	BUG_ON(stripe_index >= map->num_stripes);
-
 	*phys = map->stripes[stripe_index].physical + stripe_offset +
 		stripe_nr * map->stripe_len;
 
-	if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
+	if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1)) {
 		/* we limit the length of each bio to what fits in a stripe */
 		*length = min_t(u64, ce->size - offset,
 			      map->stripe_len - stripe_offset);
@@ -846,6 +865,7 @@ static int read_one_dev(struct btrfs_root *root,
 		device = kmalloc(sizeof(*device), GFP_NOFS);
 		if (!device)
 			return -ENOMEM;
+		device->total_ios = 0;
 		list_add(&device->dev_list,
 			 &root->fs_info->fs_devices->devices);
 	}

volumes.h

@@ -22,6 +22,8 @@ struct btrfs_device {
 	struct list_head dev_list;
 	struct btrfs_root *dev_root;
 
+	u64 total_ios;
+
 	int fd;
 
 	char *name;
@@ -67,9 +69,9 @@ struct btrfs_fs_devices {
 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 			   struct btrfs_device *device,
 			   u64 owner, u64 num_bytes, u64 *start);
-int btrfs_map_block(struct btrfs_mapping_tree *map_tree,
+int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw, int stripe_nr,
 		    u64 logical, u64 *phys, u64 *length,
-		    struct btrfs_device **dev);
+		    struct btrfs_device **dev, int *total_stripes);
 int btrfs_read_sys_array(struct btrfs_root *root);
 int btrfs_read_chunk_tree(struct btrfs_root *root);
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,