btrfs-progs: mkfs: Prevent temporary system chunk to use space in reserved 1M range
When creating btrfs, mkfs.btrfs will firstly create a temporary system chunk as basis, and then created needed trees or new devices. However the layout temporary system chunk is hard-coded and uses reserved [0, 1M) range of devid 1. Change the temporary chunk layout from old: 0 1M 4M 5M |<----------- temp chunk -------------->| And it's 1:1 mapped, which means it's a SINGLE chunk, and stripe offset is also 0. to new layout: 0 1M 4M 5M |<----------- temp chunk -------------->| And still keeps the 1:1 mapping. However this also affects btrfs_min_dev_size() which still assume temporary chunks starts at device offset 0. The problem can only be exposed by "-m single" or "-M" where we reuse the temporary chunk. With other meta profiles, system and meta chunks are allocated by later btrfs_alloc_chunk() call, and old SINGLE chunks are removed, so it will be no such problem for other meta profiles. Reported-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> [ folded fix for the minimal device size calculation ] Signed-off-by: David Sterba <dsterba@suse.com>
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@ -100,6 +100,21 @@ static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
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*
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* The superblock signature is not valid, denotes a partially created
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* filesystem, needs to be finalized.
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*
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* The temporary fs will have the following chunk layout:
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* Device extent:
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* 0 1M 5M ......
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* | Reserved | dev extent for SYS chunk |
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*
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* And chunk mapping will be:
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* Chunk mapping:
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* 0 1M 5M
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* | | System chunk, 1:1 mapped |
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*
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* That's to say, there will only be *ONE* system chunk, mapped to
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* [1M, 5M) physical offset.
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* And the only chunk is also in logical address [1M, 5M), containing
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* all essential tree blocks.
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*/
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int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
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{
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@ -154,8 +169,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
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cfg->blocks[MKFS_SUPER_BLOCK] = BTRFS_SUPER_INFO_OFFSET;
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for (i = 1; i < MKFS_BLOCK_COUNT; i++) {
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cfg->blocks[i] = BTRFS_SUPER_INFO_OFFSET + SZ_1M +
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cfg->nodesize * i;
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cfg->blocks[i] = BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
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cfg->nodesize * (i - 1);
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}
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btrfs_set_super_bytenr(&super, cfg->blocks[MKFS_SUPER_BLOCK]);
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@ -309,7 +324,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
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/* then we have chunk 0 */
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btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
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btrfs_set_disk_key_offset(&disk_key, 0);
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btrfs_set_disk_key_offset(&disk_key, BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
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btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
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btrfs_set_item_key(buf, &disk_key, nritems);
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btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
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@ -325,7 +340,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
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btrfs_set_chunk_sector_size(buf, chunk, cfg->sectorsize);
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btrfs_set_chunk_num_stripes(buf, chunk, 1);
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btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
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btrfs_set_stripe_offset_nr(buf, chunk, 0, 0);
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btrfs_set_stripe_offset_nr(buf, chunk, 0,
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BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
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nritems++;
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write_extent_buffer(buf, super.dev_item.uuid,
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@ -363,7 +379,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
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sizeof(struct btrfs_dev_extent);
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btrfs_set_disk_key_objectid(&disk_key, 1);
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btrfs_set_disk_key_offset(&disk_key, 0);
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btrfs_set_disk_key_offset(&disk_key, BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
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btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
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btrfs_set_item_key(buf, &disk_key, nritems);
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btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
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@ -374,7 +390,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
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BTRFS_CHUNK_TREE_OBJECTID);
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btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
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BTRFS_FIRST_CHUNK_TREE_OBJECTID);
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btrfs_set_dev_extent_chunk_offset(buf, dev_extent, 0);
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btrfs_set_dev_extent_chunk_offset(buf, dev_extent,
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BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
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write_extent_buffer(buf, chunk_tree_uuid,
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(unsigned long)btrfs_dev_extent_chunk_tree_uuid(dev_extent),
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@ -466,6 +483,8 @@ u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
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/*
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* Minimal size calculation is complex due to several factors:
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* 0) Reserved 1M range.
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*
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* 1) Temporary chunk reuse
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* If specified chunk profile is SINGLE, we can reuse
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* temporary chunks, no need to allocate new chunks.
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@ -484,7 +503,8 @@ u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
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* The latter two are all 8M, accroding to @calc_size of
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* btrfs_alloc_chunk().
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*/
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reserved += BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
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reserved += BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
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BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
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/*
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* For real chunks, we need to select different sizes:
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@ -66,10 +66,15 @@ static int create_metadata_block_groups(struct btrfs_root *root, int mixed,
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bytes_used = btrfs_super_bytes_used(fs_info->super_copy);
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root->fs_info->system_allocs = 1;
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/*
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* First temporary system chunk must match the chunk layout
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* created in make_btrfs().
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*/
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ret = btrfs_make_block_group(trans, fs_info, bytes_used,
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BTRFS_BLOCK_GROUP_SYSTEM,
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BTRFS_FIRST_CHUNK_TREE_OBJECTID,
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0, BTRFS_MKFS_SYSTEM_GROUP_SIZE);
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BTRFS_BLOCK_RESERVED_1M_FOR_SUPER,
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BTRFS_MKFS_SYSTEM_GROUP_SIZE);
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allocation->system += BTRFS_MKFS_SYSTEM_GROUP_SIZE;
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if (ret)
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return ret;
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