[PATCH v2 02/10] btrfs-progs: Merge btrfs_alloc_data_chunk into btrfs_alloc_chunk

[Qu Wenruo <wqu@suse.com>]

We used to have two chunk allocators, btrfs_alloc_chunk() and
btrfs_alloc_data_chunk(), the former is the more generic one, while the
later is only used in mkfs and convert, to allocate SINGLE data chunk.

Although btrfs_alloc_data_chunk() has some special hacks to cooperate
with convert, it's quite simple to integrity it into the generic chunk
allocator.

So merge them into one btrfs_alloc_chunk(), with extra @convert
parameter and necessary comment, to make code less duplicated and less
thing to maintain.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 convert/main.c |   6 +-
 extent-tree.c  |   2 +-
 mkfs/main.c    |   8 +--
 volumes.c      | 219 ++++++++++++++++++++++-----------------------------------
 volumes.h      |   5 +-
 5 files changed, 94 insertions(+), 146 deletions(-)

diff --git a/convert/main.c b/convert/main.c
index b3ea31d7af43..b2444bb2ff21 100644
--- a/convert/main.c
+++ b/convert/main.c
@@ -910,9 +910,9 @@ static int make_convert_data_block_groups(struct btrfs_trans_handle *trans,
 
 			len = min(max_chunk_size,
 				  cache->start + cache->size - cur);
-			ret = btrfs_alloc_data_chunk(trans, fs_info,
-					&cur_backup, len,
-					BTRFS_BLOCK_GROUP_DATA, 1);
+			ret = btrfs_alloc_chunk(trans, fs_info,
+					&cur_backup, &len,
+					BTRFS_BLOCK_GROUP_DATA, true);
 			if (ret < 0)
 				break;
 			ret = btrfs_make_block_group(trans, fs_info, 0,
diff --git a/extent-tree.c b/extent-tree.c
index e2ae74a7fe66..b085ab0352b3 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -1906,7 +1906,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 		return 0;
 
 	ret = btrfs_alloc_chunk(trans, fs_info, &start, &num_bytes,
-	                        space_info->flags);
+	                        space_info->flags, false);
 	if (ret == -ENOSPC) {
 		space_info->full = 1;
 		return 0;
diff --git a/mkfs/main.c b/mkfs/main.c
index ea65c6d897b2..358395ca0250 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -82,7 +82,7 @@ static int create_metadata_block_groups(struct btrfs_root *root, int mixed,
 		ret = btrfs_alloc_chunk(trans, fs_info,
 					&chunk_start, &chunk_size,
 					BTRFS_BLOCK_GROUP_METADATA |
-					BTRFS_BLOCK_GROUP_DATA);
+					BTRFS_BLOCK_GROUP_DATA, false);
 		if (ret == -ENOSPC) {
 			error("no space to allocate data/metadata chunk");
 			goto err;
@@ -99,7 +99,7 @@ static int create_metadata_block_groups(struct btrfs_root *root, int mixed,
 	} else {
 		ret = btrfs_alloc_chunk(trans, fs_info,
 					&chunk_start, &chunk_size,
-					BTRFS_BLOCK_GROUP_METADATA);
+					BTRFS_BLOCK_GROUP_METADATA, false);
 		if (ret == -ENOSPC) {
 			error("no space to allocate metadata chunk");
 			goto err;
@@ -133,7 +133,7 @@ static int create_data_block_groups(struct btrfs_trans_handle *trans,
 	if (!mixed) {
 		ret = btrfs_alloc_chunk(trans, fs_info,
 					&chunk_start, &chunk_size,
-					BTRFS_BLOCK_GROUP_DATA);
+					BTRFS_BLOCK_GROUP_DATA, false);
 		if (ret == -ENOSPC) {
 			error("no space to allocate data chunk");
 			goto err;
@@ -241,7 +241,7 @@ static int create_one_raid_group(struct btrfs_trans_handle *trans,
 	int ret;
 
 	ret = btrfs_alloc_chunk(trans, fs_info,
-				&chunk_start, &chunk_size, type);
+				&chunk_start, &chunk_size, type, false);
 	if (ret == -ENOSPC) {
 		error("not enough free space to allocate chunk");
 		exit(1);
diff --git a/volumes.c b/volumes.c
index 677d085de96c..9ee4650351c3 100644
--- a/volumes.c
+++ b/volumes.c
@@ -836,9 +836,23 @@ error:
 				- 2 * sizeof(struct btrfs_chunk))	\
 				/ sizeof(struct btrfs_stripe) + 1)
 
+/*
+ * Alloc a chunk, will insert dev extents, chunk item.
+ * NOTE: This function will not insert block group item nor mark newly
+ * allocated chunk available for later allocation.
+ * Block group item and free space update is handled by btrfs_make_block_group()
+ *
+ * @start:	return value of allocated chunk start bytenr.
+ * @num_bytes:	return value of allocated chunk size
+ * @type:	chunk type (including both profile and type)
+ * @convert:	if the chunk is allocated for convert case.
+ * 		If @convert is true, chunk allocator will skip device extent
+ * 		search, but use *start and *num_bytes as chunk start/num_bytes
+ * 		and devive offset, to build a 1:1 chunk mapping for convert.
+ */
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 		      struct btrfs_fs_info *info, u64 *start,
-		      u64 *num_bytes, u64 type)
+		      u64 *num_bytes, u64 type, bool convert)
 {
 	u64 dev_offset;
 	struct btrfs_root *extent_root = info->extent_root;
@@ -868,10 +882,38 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	struct btrfs_key key;
 	u64 offset;
 
-	if (list_empty(dev_list)) {
+	if (list_empty(dev_list))
 		return -ENOSPC;
+
+	if (convert) {
+		/* For convert, profile must be SINGLE */
+		if (type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
+			error("convert only suports SINGLE profile");
+			return -EINVAL;
+		}
+		if (!IS_ALIGNED(*start, info->sectorsize)) {
+			error("chunk start not aligned, start=%llu sectorsize=%u",
+				*start, info->sectorsize);
+			return -EINVAL;
+		}
+		if (!IS_ALIGNED(*num_bytes, info->sectorsize)) {
+			error("chunk size not aligned, size=%llu sectorsize=%u",
+				*num_bytes, info->sectorsize);
+			return -EINVAL;
+		}
+		calc_size = *num_bytes;
+		offset = *start;
+		/*
+		 * For convert, we use 1:1 chunk mapping specified by @start and
+		 * @num_bytes, so there is no need to go through dev_extent
+		 * searching.
+		 */
+		goto alloc_chunk;
 	}
 
+	/*
+	 * Chunk size calculation part.
+	 */
 	if (type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
 		if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
 			calc_size = SZ_8M;
@@ -942,6 +984,9 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	percent_max = div_factor(btrfs_super_total_bytes(info->super_copy), 1);
 	max_chunk_size = min(percent_max, max_chunk_size);
 
+	/*
+	 * Reserve space from each device.
+	 */
 again:
 	if (chunk_bytes_by_type(type, calc_size, num_stripes, sub_stripes) >
 	    max_chunk_size) {
@@ -972,7 +1017,8 @@ again:
 			return ret;
 		cur = cur->next;
 		if (avail >= min_free) {
-			list_move_tail(&device->dev_list, &private_devs);
+			list_move_tail(&device->dev_list,
+				       &private_devs);
 			index++;
 			if (type & BTRFS_BLOCK_GROUP_DUP)
 				index++;
@@ -999,9 +1045,16 @@ again:
 		}
 		return -ENOSPC;
 	}
-	ret = find_next_chunk(info, &offset);
-	if (ret)
-		return ret;
+
+	/*
+	 * Fill chunk mapping and chunk stripes
+	 */
+alloc_chunk:
+	if (!convert) {
+		ret = find_next_chunk(info, &offset);
+		if (ret)
+			return ret;
+	}
 	key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
 	key.type = BTRFS_CHUNK_ITEM_KEY;
 	key.offset = offset;
@@ -1022,17 +1075,31 @@ again:
 	index = 0;
 	while(index < num_stripes) {
 		struct btrfs_stripe *stripe;
-		BUG_ON(list_empty(&private_devs));
-		cur = private_devs.next;
-		device = list_entry(cur, struct btrfs_device, dev_list);
 
-		/* loop over this device again if we're doing a dup group */
-		if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
-		    (index == num_stripes - 1))
-			list_move_tail(&device->dev_list, dev_list);
+		if (!convert) {
+			if (list_empty(&private_devs))
+				return -ENODEV;
+			cur = private_devs.next;
+			device = list_entry(cur, struct btrfs_device, dev_list);
+			if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
+			    (index == num_stripes - 1)) {
+				/*
+				 * loop over this device again if we're doing a
+				 * dup group
+				 */
+				list_move_tail(&device->dev_list, dev_list);
+			}
+		} else {
+			/* Only SINGLE is accepted in convert case */
+			BUG_ON(num_stripes > 1);
+			device = list_entry(dev_list->next, struct btrfs_device,
+					    dev_list);
+			key.offset = *start;
+			dev_offset = *start;
+		}
 
 		ret = btrfs_alloc_dev_extent(trans, device, key.offset,
-			     calc_size, &dev_offset, 0);
+			     calc_size, &dev_offset, convert);
 		if (ret < 0)
 			goto out_chunk_map;
 
@@ -1049,7 +1116,7 @@ again:
 		memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
 		index++;
 	}
-	BUG_ON(!list_empty(&private_devs));
+	BUG_ON(!convert && !list_empty(&private_devs));
 
 	/* key was set above */
 	btrfs_set_stack_chunk_length(chunk, *num_bytes);
@@ -1069,6 +1136,9 @@ again:
 	map->num_stripes = num_stripes;
 	map->sub_stripes = sub_stripes;
 
+	/*
+	 * Insert chunk item and chunk mapping.
+	 */
 	ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
 				btrfs_chunk_item_size(num_stripes));
 	BUG_ON(ret);
@@ -1098,125 +1168,6 @@ out_chunk:
 	return ret;
 }
 
-/*
- * Alloc a DATA chunk with SINGLE profile.
- *
- * If 'convert' is set, it will alloc a chunk with 1:1 mapping
- * (btrfs logical bytenr == on-disk bytenr)
- * For that case, caller must make sure the chunk and dev_extent are not
- * occupied.
- */
-int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
-			   struct btrfs_fs_info *info, u64 *start,
-			   u64 num_bytes, u64 type, int convert)
-{
-	u64 dev_offset;
-	struct btrfs_root *extent_root = info->extent_root;
-	struct btrfs_root *chunk_root = info->chunk_root;
-	struct btrfs_stripe *stripes;
-	struct btrfs_device *device = NULL;
-	struct btrfs_chunk *chunk;
-	struct list_head *dev_list = &info->fs_devices->devices;
-	struct list_head *cur;
-	struct map_lookup *map;
-	u64 calc_size = SZ_8M;
-	int num_stripes = 1;
-	int sub_stripes = 0;
-	int ret;
-	int index;
-	int stripe_len = BTRFS_STRIPE_LEN;
-	struct btrfs_key key;
-
-	key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
-	key.type = BTRFS_CHUNK_ITEM_KEY;
-	if (convert) {
-		if (*start != round_down(*start, info->sectorsize)) {
-			error("DATA chunk start not sectorsize aligned: %llu",
-					(unsigned long long)*start);
-			return -EINVAL;
-		}
-		key.offset = *start;
-		dev_offset = *start;
-	} else {
-		u64 tmp;
-
-		ret = find_next_chunk(info, &tmp);
-		key.offset = tmp;
-		if (ret)
-			return ret;
-	}
-
-	chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
-	if (!chunk)
-		return -ENOMEM;
-
-	map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
-	if (!map) {
-		kfree(chunk);
-		return -ENOMEM;
-	}
-
-	stripes = &chunk->stripe;
-	calc_size = num_bytes;
-
-	index = 0;
-	cur = dev_list->next;
-	device = list_entry(cur, struct btrfs_device, dev_list);
-
-	while (index < num_stripes) {
-		struct btrfs_stripe *stripe;
-
-		ret = btrfs_alloc_dev_extent(trans, device, key.offset,
-			     calc_size, &dev_offset, convert);
-		BUG_ON(ret);
-
-		device->bytes_used += calc_size;
-		ret = btrfs_update_device(trans, device);
-		BUG_ON(ret);
-
-		map->stripes[index].dev = device;
-		map->stripes[index].physical = dev_offset;
-		stripe = stripes + index;
-		btrfs_set_stack_stripe_devid(stripe, device->devid);
-		btrfs_set_stack_stripe_offset(stripe, dev_offset);
-		memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
-		index++;
-	}
-
-	/* key was set above */
-	btrfs_set_stack_chunk_length(chunk, num_bytes);
-	btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
-	btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
-	btrfs_set_stack_chunk_type(chunk, type);
-	btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
-	btrfs_set_stack_chunk_io_align(chunk, stripe_len);
-	btrfs_set_stack_chunk_io_width(chunk, stripe_len);
-	btrfs_set_stack_chunk_sector_size(chunk, info->sectorsize);
-	btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
-	map->sector_size = info->sectorsize;
-	map->stripe_len = stripe_len;
-	map->io_align = stripe_len;
-	map->io_width = stripe_len;
-	map->type = type;
-	map->num_stripes = num_stripes;
-	map->sub_stripes = sub_stripes;
-
-	ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
-				btrfs_chunk_item_size(num_stripes));
-	BUG_ON(ret);
-	if (!convert)
-		*start = key.offset;
-
-	map->ce.start = key.offset;
-	map->ce.size = num_bytes;
-
-	ret = insert_cache_extent(&info->mapping_tree.cache_tree, &map->ce);
-	BUG_ON(ret);
-
-	kfree(chunk);
-	return ret;
-}
-
 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 {
 	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
diff --git a/volumes.h b/volumes.h
index 11572e78c04f..7bbdf615d31a 100644
--- a/volumes.h
+++ b/volumes.h
@@ -208,10 +208,7 @@ int btrfs_read_sys_array(struct btrfs_fs_info *fs_info);
 int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 		      struct btrfs_fs_info *fs_info, u64 *start,
-		      u64 *num_bytes, u64 type);
-int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
-			   struct btrfs_fs_info *fs_info, u64 *start,
-			   u64 num_bytes, u64 type, int convert);
+		      u64 *num_bytes, u64 type, bool convert);
 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 		       int flags);
 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
-- 
2.16.1