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Diffstat (limited to 'mkfs')
-rw-r--r--mkfs/common.c34
-rw-r--r--mkfs/main.c7
2 files changed, 33 insertions, 8 deletions
diff --git a/mkfs/common.c b/mkfs/common.c
index dd5e7ecf..8e85942e 100644
--- a/mkfs/common.c
+++ b/mkfs/common.c
@@ -100,6 +100,21 @@ static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
*
* The superblock signature is not valid, denotes a partially created
* filesystem, needs to be finalized.
+ *
+ * The temporary fs will have the following chunk layout:
+ * Device extent:
+ * 0 1M 5M ......
+ * | Reserved | dev extent for SYS chunk |
+ *
+ * And chunk mapping will be:
+ * Chunk mapping:
+ * 0 1M 5M
+ * | | System chunk, 1:1 mapped |
+ *
+ * That's to say, there will only be *ONE* system chunk, mapped to
+ * [1M, 5M) physical offset.
+ * And the only chunk is also in logical address [1M, 5M), containing
+ * all essential tree blocks.
*/
int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
{
@@ -154,8 +169,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
cfg->blocks[MKFS_SUPER_BLOCK] = BTRFS_SUPER_INFO_OFFSET;
for (i = 1; i < MKFS_BLOCK_COUNT; i++) {
- cfg->blocks[i] = BTRFS_SUPER_INFO_OFFSET + SZ_1M +
- cfg->nodesize * i;
+ cfg->blocks[i] = BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
+ cfg->nodesize * (i - 1);
}
btrfs_set_super_bytenr(&super, cfg->blocks[MKFS_SUPER_BLOCK]);
@@ -309,7 +324,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
/* then we have chunk 0 */
btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
- btrfs_set_disk_key_offset(&disk_key, 0);
+ btrfs_set_disk_key_offset(&disk_key, BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
btrfs_set_item_key(buf, &disk_key, nritems);
btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
@@ -325,7 +340,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
btrfs_set_chunk_sector_size(buf, chunk, cfg->sectorsize);
btrfs_set_chunk_num_stripes(buf, chunk, 1);
btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
- btrfs_set_stripe_offset_nr(buf, chunk, 0, 0);
+ btrfs_set_stripe_offset_nr(buf, chunk, 0,
+ BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
nritems++;
write_extent_buffer(buf, super.dev_item.uuid,
@@ -363,7 +379,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
sizeof(struct btrfs_dev_extent);
btrfs_set_disk_key_objectid(&disk_key, 1);
- btrfs_set_disk_key_offset(&disk_key, 0);
+ btrfs_set_disk_key_offset(&disk_key, BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
btrfs_set_item_key(buf, &disk_key, nritems);
btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
@@ -374,7 +390,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
BTRFS_CHUNK_TREE_OBJECTID);
btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
BTRFS_FIRST_CHUNK_TREE_OBJECTID);
- btrfs_set_dev_extent_chunk_offset(buf, dev_extent, 0);
+ btrfs_set_dev_extent_chunk_offset(buf, dev_extent,
+ BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
write_extent_buffer(buf, chunk_tree_uuid,
(unsigned long)btrfs_dev_extent_chunk_tree_uuid(dev_extent),
@@ -466,6 +483,8 @@ u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
/*
* Minimal size calculation is complex due to several factors:
+ * 0) Reserved 1M range.
+ *
* 1) Temporary chunk reuse
* If specified chunk profile is SINGLE, we can reuse
* temporary chunks, no need to allocate new chunks.
@@ -484,7 +503,8 @@ u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
* The latter two are all 8M, accroding to @calc_size of
* btrfs_alloc_chunk().
*/
- reserved += BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
+ reserved += BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
+ BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
/*
* For real chunks, we need to select different sizes:
diff --git a/mkfs/main.c b/mkfs/main.c
index 1a3852e4..9bb1f602 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -66,10 +66,15 @@ static int create_metadata_block_groups(struct btrfs_root *root, int mixed,
bytes_used = btrfs_super_bytes_used(fs_info->super_copy);
root->fs_info->system_allocs = 1;
+ /*
+ * First temporary system chunk must match the chunk layout
+ * created in make_btrfs().
+ */
ret = btrfs_make_block_group(trans, fs_info, bytes_used,
BTRFS_BLOCK_GROUP_SYSTEM,
BTRFS_FIRST_CHUNK_TREE_OBJECTID,
- 0, BTRFS_MKFS_SYSTEM_GROUP_SIZE);
+ BTRFS_BLOCK_RESERVED_1M_FOR_SUPER,
+ BTRFS_MKFS_SYSTEM_GROUP_SIZE);
allocation->system += BTRFS_MKFS_SYSTEM_GROUP_SIZE;
if (ret)
return ret;