btrfs-progs: introduce global config
[platform/upstream/btrfs-progs.git] / utils.c
diff --git a/utils.c b/utils.c
index 2af10c4..1adcc84 100644 (file)
--- a/utils.c
+++ b/utils.c
@@ -38,6 +38,8 @@
 #include <sys/statfs.h>
 #include <linux/magic.h>
 #include <getopt.h>
+#include <sys/utsname.h>
+#include <linux/version.h>
 
 #include "kerncompat.h"
 #include "radix-tree.h"
@@ -58,6 +60,11 @@ static int btrfs_scan_done = 0;
 
 static char argv0_buf[ARGV0_BUF_SIZE] = "btrfs";
 
+static int rand_seed_initlized = 0;
+static unsigned short rand_seed[3];
+
+struct btrfs_config bconf;
+
 const char *get_argv0_buf(void)
 {
        return argv0_buf;
@@ -179,7 +186,873 @@ int test_uuid_unique(char *fs_uuid)
 }
 
 /*
+ * Reserve space from free_tree.
+ * The algorithm is very simple, find the first cache_extent with enough space
+ * and allocate from its beginning.
+ */
+static int reserve_free_space(struct cache_tree *free_tree, u64 len,
+                             u64 *ret_start)
+{
+       struct cache_extent *cache;
+       int found = 0;
+
+       ASSERT(ret_start != NULL);
+       cache = first_cache_extent(free_tree);
+       while (cache) {
+               if (cache->size > len) {
+                       found = 1;
+                       *ret_start = cache->start;
+
+                       cache->size -= len;
+                       if (cache->size == 0) {
+                               remove_cache_extent(free_tree, cache);
+                               free(cache);
+                       } else {
+                               cache->start += len;
+                       }
+                       break;
+               }
+               cache = next_cache_extent(cache);
+       }
+       if (!found)
+               return -ENOSPC;
+       return 0;
+}
+
+static inline int write_temp_super(int fd, struct btrfs_super_block *sb,
+                                  u64 sb_bytenr)
+{
+       u32 crc = ~(u32)0;
+       int ret;
+
+       crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, crc,
+                             BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
+       btrfs_csum_final(crc, &sb->csum[0]);
+       ret = pwrite(fd, sb, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
+       if (ret < BTRFS_SUPER_INFO_SIZE)
+               ret = (ret < 0 ? -errno : -EIO);
+       else
+               ret = 0;
+       return ret;
+}
+
+/*
+ * Setup temporary superblock at cfg->super_bynter
+ * Needed info are extracted from cfg, and root_bytenr, chunk_bytenr
+ *
+ * For now sys chunk array will be empty and dev_item is empty too.
+ * They will be re-initialized at temp chunk tree setup.
+ *
+ * The superblock signature is not valid, denotes a partially created
+ * filesystem, needs to be finalized.
+ */
+static int setup_temp_super(int fd, struct btrfs_mkfs_config *cfg,
+                           u64 root_bytenr, u64 chunk_bytenr)
+{
+       unsigned char chunk_uuid[BTRFS_UUID_SIZE];
+       char super_buf[BTRFS_SUPER_INFO_SIZE];
+       struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
+       int ret;
+
+       memset(super_buf, 0, BTRFS_SUPER_INFO_SIZE);
+       cfg->num_bytes = round_down(cfg->num_bytes, cfg->sectorsize);
+
+       if (*cfg->fs_uuid) {
+               if (uuid_parse(cfg->fs_uuid, super->fsid) != 0) {
+                       error("cound not parse UUID: %s", cfg->fs_uuid);
+                       ret = -EINVAL;
+                       goto out;
+               }
+               if (!test_uuid_unique(cfg->fs_uuid)) {
+                       error("non-unique UUID: %s", cfg->fs_uuid);
+                       ret = -EINVAL;
+                       goto out;
+               }
+       } else {
+               uuid_generate(super->fsid);
+               uuid_unparse(super->fsid, cfg->fs_uuid);
+       }
+       uuid_generate(chunk_uuid);
+       uuid_unparse(chunk_uuid, cfg->chunk_uuid);
+
+       btrfs_set_super_bytenr(super, cfg->super_bytenr);
+       btrfs_set_super_num_devices(super, 1);
+       btrfs_set_super_magic(super, BTRFS_MAGIC_PARTIAL);
+       btrfs_set_super_generation(super, 1);
+       btrfs_set_super_root(super, root_bytenr);
+       btrfs_set_super_chunk_root(super, chunk_bytenr);
+       btrfs_set_super_total_bytes(super, cfg->num_bytes);
+       /*
+        * Temporary filesystem will only have 6 tree roots:
+        * chunk tree, root tree, extent_tree, device tree, fs tree
+        * and csum tree.
+        */
+       btrfs_set_super_bytes_used(super, 6 * cfg->nodesize);
+       btrfs_set_super_sectorsize(super, cfg->sectorsize);
+       btrfs_set_super_leafsize(super, cfg->nodesize);
+       btrfs_set_super_nodesize(super, cfg->nodesize);
+       btrfs_set_super_stripesize(super, cfg->stripesize);
+       btrfs_set_super_csum_type(super, BTRFS_CSUM_TYPE_CRC32);
+       btrfs_set_super_chunk_root(super, chunk_bytenr);
+       btrfs_set_super_cache_generation(super, -1);
+       btrfs_set_super_incompat_flags(super, cfg->features);
+       if (cfg->label)
+               __strncpy_null(super->label, cfg->label, BTRFS_LABEL_SIZE - 1);
+
+       /* Sys chunk array will be re-initialized at chunk tree init time */
+       super->sys_chunk_array_size = 0;
+
+       ret = write_temp_super(fd, super, cfg->super_bytenr);
+out:
+       return ret;
+}
+
+/*
+ * Setup an extent buffer for tree block.
+ */
+static int setup_temp_extent_buffer(struct extent_buffer *buf,
+                                   struct btrfs_mkfs_config *cfg,
+                                   u64 bytenr, u64 owner)
+{
+       unsigned char fsid[BTRFS_FSID_SIZE];
+       unsigned char chunk_uuid[BTRFS_UUID_SIZE];
+       int ret;
+
+       ret = uuid_parse(cfg->fs_uuid, fsid);
+       if (ret)
+               return -EINVAL;
+       ret = uuid_parse(cfg->chunk_uuid, chunk_uuid);
+       if (ret)
+               return -EINVAL;
+
+       memset(buf->data, 0, cfg->nodesize);
+       buf->len = cfg->nodesize;
+       btrfs_set_header_bytenr(buf, bytenr);
+       btrfs_set_header_generation(buf, 1);
+       btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
+       btrfs_set_header_owner(buf, owner);
+       btrfs_set_header_flags(buf, BTRFS_HEADER_FLAG_WRITTEN);
+       write_extent_buffer(buf, chunk_uuid, btrfs_header_chunk_tree_uuid(buf),
+                           BTRFS_UUID_SIZE);
+       write_extent_buffer(buf, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
+       return 0;
+}
+
+static inline int write_temp_extent_buffer(int fd, struct extent_buffer *buf,
+                                          u64 bytenr)
+{
+       int ret;
+
+       csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
+
+       /* Temporary extent buffer is always mapped 1:1 on disk */
+       ret = pwrite(fd, buf->data, buf->len, bytenr);
+       if (ret < buf->len)
+               ret = (ret < 0 ? ret : -EIO);
+       else
+               ret = 0;
+       return ret;
+}
+
+/*
+ * Insert a root item for temporary tree root
+ *
+ * Only used in make_btrfs_v2().
+ */
+static void insert_temp_root_item(struct extent_buffer *buf,
+                                 struct btrfs_mkfs_config *cfg,
+                                 int *slot, u32 *itemoff, u64 objectid,
+                                 u64 bytenr)
+{
+       struct btrfs_root_item root_item;
+       struct btrfs_inode_item *inode_item;
+       struct btrfs_disk_key disk_key;
+
+       btrfs_set_header_nritems(buf, *slot + 1);
+       (*itemoff) -= sizeof(root_item);
+       memset(&root_item, 0, sizeof(root_item));
+       inode_item = &root_item.inode;
+       btrfs_set_stack_inode_generation(inode_item, 1);
+       btrfs_set_stack_inode_size(inode_item, 3);
+       btrfs_set_stack_inode_nlink(inode_item, 1);
+       btrfs_set_stack_inode_nbytes(inode_item, cfg->nodesize);
+       btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
+       btrfs_set_root_refs(&root_item, 1);
+       btrfs_set_root_used(&root_item, cfg->nodesize);
+       btrfs_set_root_generation(&root_item, 1);
+       btrfs_set_root_bytenr(&root_item, bytenr);
+
+       memset(&disk_key, 0, sizeof(disk_key));
+       btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
+       btrfs_set_disk_key_objectid(&disk_key, objectid);
+       btrfs_set_disk_key_offset(&disk_key, 0);
+
+       btrfs_set_item_key(buf, &disk_key, *slot);
+       btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+       btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(root_item));
+       write_extent_buffer(buf, &root_item,
+                           btrfs_item_ptr_offset(buf, *slot),
+                           sizeof(root_item));
+       (*slot)++;
+}
+
+static int setup_temp_root_tree(int fd, struct btrfs_mkfs_config *cfg,
+                               u64 root_bytenr, u64 extent_bytenr,
+                               u64 dev_bytenr, u64 fs_bytenr, u64 csum_bytenr)
+{
+       struct extent_buffer *buf = NULL;
+       u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+       int slot = 0;
+       int ret;
+
+       /*
+        * Provided bytenr must in ascending order, or tree root will have a
+        * bad key order.
+        */
+       if (!(root_bytenr < extent_bytenr && extent_bytenr < dev_bytenr &&
+             dev_bytenr < fs_bytenr && fs_bytenr < csum_bytenr)) {
+               error("bad tree bytenr order: "
+                               "root < extent %llu < %llu, "
+                               "extent < dev %llu < %llu, "
+                               "dev < fs %llu < %llu, "
+                               "fs < csum %llu < %llu",
+                               (unsigned long long)root_bytenr,
+                               (unsigned long long)extent_bytenr,
+                               (unsigned long long)extent_bytenr,
+                               (unsigned long long)dev_bytenr,
+                               (unsigned long long)dev_bytenr,
+                               (unsigned long long)fs_bytenr,
+                               (unsigned long long)fs_bytenr,
+                               (unsigned long long)csum_bytenr);
+               return -EINVAL;
+       }
+       buf = malloc(sizeof(*buf) + cfg->nodesize);
+       if (!buf)
+               return -ENOMEM;
+
+       ret = setup_temp_extent_buffer(buf, cfg, root_bytenr,
+                                      BTRFS_ROOT_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+
+       insert_temp_root_item(buf, cfg, &slot, &itemoff,
+                             BTRFS_EXTENT_TREE_OBJECTID, extent_bytenr);
+       insert_temp_root_item(buf, cfg, &slot, &itemoff,
+                             BTRFS_DEV_TREE_OBJECTID, dev_bytenr);
+       insert_temp_root_item(buf, cfg, &slot, &itemoff,
+                             BTRFS_FS_TREE_OBJECTID, fs_bytenr);
+       insert_temp_root_item(buf, cfg, &slot, &itemoff,
+                             BTRFS_CSUM_TREE_OBJECTID, csum_bytenr);
+
+       ret = write_temp_extent_buffer(fd, buf, root_bytenr);
+out:
+       free(buf);
+       return ret;
+}
+
+static int insert_temp_dev_item(int fd, struct extent_buffer *buf,
+                               struct btrfs_mkfs_config *cfg,
+                               int *slot, u32 *itemoff)
+{
+       struct btrfs_disk_key disk_key;
+       struct btrfs_dev_item *dev_item;
+       char super_buf[BTRFS_SUPER_INFO_SIZE];
+       unsigned char dev_uuid[BTRFS_UUID_SIZE];
+       unsigned char fsid[BTRFS_FSID_SIZE];
+       struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
+       int ret;
+
+       ret = pread(fd, super_buf, BTRFS_SUPER_INFO_SIZE, cfg->super_bytenr);
+       if (ret < BTRFS_SUPER_INFO_SIZE) {
+               ret = (ret < 0 ? -errno : -EIO);
+               goto out;
+       }
+
+       btrfs_set_header_nritems(buf, *slot + 1);
+       (*itemoff) -= sizeof(*dev_item);
+       /* setup device item 1, 0 is for replace case */
+       btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_ITEM_KEY);
+       btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_ITEMS_OBJECTID);
+       btrfs_set_disk_key_offset(&disk_key, 1);
+       btrfs_set_item_key(buf, &disk_key, *slot);
+       btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+       btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(*dev_item));
+
+       dev_item = btrfs_item_ptr(buf, *slot, struct btrfs_dev_item);
+       /* Generate device uuid */
+       uuid_generate(dev_uuid);
+       write_extent_buffer(buf, dev_uuid,
+                       (unsigned long)btrfs_device_uuid(dev_item),
+                       BTRFS_UUID_SIZE);
+       uuid_parse(cfg->fs_uuid, fsid);
+       write_extent_buffer(buf, fsid,
+                       (unsigned long)btrfs_device_fsid(dev_item),
+                       BTRFS_FSID_SIZE);
+       btrfs_set_device_id(buf, dev_item, 1);
+       btrfs_set_device_generation(buf, dev_item, 0);
+       btrfs_set_device_total_bytes(buf, dev_item, cfg->num_bytes);
+       /*
+        * The number must match the initial SYSTEM and META chunk size
+        */
+       btrfs_set_device_bytes_used(buf, dev_item,
+                       BTRFS_MKFS_SYSTEM_GROUP_SIZE +
+                       BTRFS_CONVERT_META_GROUP_SIZE);
+       btrfs_set_device_io_align(buf, dev_item, cfg->sectorsize);
+       btrfs_set_device_io_width(buf, dev_item, cfg->sectorsize);
+       btrfs_set_device_sector_size(buf, dev_item, cfg->sectorsize);
+       btrfs_set_device_type(buf, dev_item, 0);
+
+       /* Super dev_item is not complete, copy the complete one to sb */
+       read_extent_buffer(buf, &super->dev_item, (unsigned long)dev_item,
+                          sizeof(*dev_item));
+       ret = write_temp_super(fd, super, cfg->super_bytenr);
+       (*slot)++;
+out:
+       return ret;
+}
+
+static int insert_temp_chunk_item(int fd, struct extent_buffer *buf,
+                                 struct btrfs_mkfs_config *cfg,
+                                 int *slot, u32 *itemoff, u64 start, u64 len,
+                                 u64 type)
+{
+       struct btrfs_chunk *chunk;
+       struct btrfs_disk_key disk_key;
+       char super_buf[BTRFS_SUPER_INFO_SIZE];
+       struct btrfs_super_block *sb = (struct btrfs_super_block *)super_buf;
+       int ret = 0;
+
+       ret = pread(fd, super_buf, BTRFS_SUPER_INFO_SIZE,
+                   cfg->super_bytenr);
+       if (ret < BTRFS_SUPER_INFO_SIZE) {
+               ret = (ret < 0 ? ret : -EIO);
+               return ret;
+       }
+
+       btrfs_set_header_nritems(buf, *slot + 1);
+       (*itemoff) -= btrfs_chunk_item_size(1);
+       btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
+       btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+       btrfs_set_disk_key_offset(&disk_key, start);
+       btrfs_set_item_key(buf, &disk_key, *slot);
+       btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+       btrfs_set_item_size(buf, btrfs_item_nr(*slot),
+                           btrfs_chunk_item_size(1));
+
+       chunk = btrfs_item_ptr(buf, *slot, struct btrfs_chunk);
+       btrfs_set_chunk_length(buf, chunk, len);
+       btrfs_set_chunk_owner(buf, chunk, BTRFS_EXTENT_TREE_OBJECTID);
+       btrfs_set_chunk_stripe_len(buf, chunk, 64 * 1024);
+       btrfs_set_chunk_type(buf, chunk, type);
+       btrfs_set_chunk_io_align(buf, chunk, cfg->sectorsize);
+       btrfs_set_chunk_io_width(buf, chunk, cfg->sectorsize);
+       btrfs_set_chunk_sector_size(buf, chunk, cfg->sectorsize);
+       btrfs_set_chunk_num_stripes(buf, chunk, 1);
+       /* TODO: Support DUP profile for system chunk */
+       btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
+       /* We are doing 1:1 mapping, so start is its dev offset */
+       btrfs_set_stripe_offset_nr(buf, chunk, 0, start);
+       write_extent_buffer(buf, &sb->dev_item.uuid,
+                           (unsigned long)btrfs_stripe_dev_uuid_nr(chunk, 0),
+                           BTRFS_UUID_SIZE);
+       (*slot)++;
+
+       /*
+        * If it's system chunk, also copy it to super block.
+        */
+       if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
+               char *cur;
+               u32 array_size;
+
+               cur = (char *)sb->sys_chunk_array
+                       + btrfs_super_sys_array_size(sb);
+               memcpy(cur, &disk_key, sizeof(disk_key));
+               cur += sizeof(disk_key);
+               read_extent_buffer(buf, cur, (unsigned long int)chunk,
+                                  btrfs_chunk_item_size(1));
+               array_size = btrfs_super_sys_array_size(sb);
+               array_size += btrfs_chunk_item_size(1) +
+                                           sizeof(disk_key);
+               btrfs_set_super_sys_array_size(sb, array_size);
+
+               ret = write_temp_super(fd, sb, cfg->super_bytenr);
+       }
+       return ret;
+}
+
+static int setup_temp_chunk_tree(int fd, struct btrfs_mkfs_config *cfg,
+                                u64 sys_chunk_start, u64 meta_chunk_start,
+                                u64 chunk_bytenr)
+{
+       struct extent_buffer *buf = NULL;
+       u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+       int slot = 0;
+       int ret;
+
+       /* Must ensure SYS chunk starts before META chunk */
+       if (meta_chunk_start < sys_chunk_start) {
+               error("wrong chunk order: meta < system %llu < %llu",
+                               (unsigned long long)meta_chunk_start,
+                               (unsigned long long)sys_chunk_start);
+               return -EINVAL;
+       }
+       buf = malloc(sizeof(*buf) + cfg->nodesize);
+       if (!buf)
+               return -ENOMEM;
+       ret = setup_temp_extent_buffer(buf, cfg, chunk_bytenr,
+                                      BTRFS_CHUNK_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+
+       ret = insert_temp_dev_item(fd, buf, cfg, &slot, &itemoff);
+       if (ret < 0)
+               goto out;
+       ret = insert_temp_chunk_item(fd, buf, cfg, &slot, &itemoff,
+                                    sys_chunk_start,
+                                    BTRFS_MKFS_SYSTEM_GROUP_SIZE,
+                                    BTRFS_BLOCK_GROUP_SYSTEM);
+       if (ret < 0)
+               goto out;
+       ret = insert_temp_chunk_item(fd, buf, cfg, &slot, &itemoff,
+                                    meta_chunk_start,
+                                    BTRFS_CONVERT_META_GROUP_SIZE,
+                                    BTRFS_BLOCK_GROUP_METADATA);
+       if (ret < 0)
+               goto out;
+       ret = write_temp_extent_buffer(fd, buf, chunk_bytenr);
+
+out:
+       free(buf);
+       return ret;
+}
+
+static void insert_temp_dev_extent(struct extent_buffer *buf,
+                                  int *slot, u32 *itemoff, u64 start, u64 len)
+{
+       struct btrfs_dev_extent *dev_extent;
+       struct btrfs_disk_key disk_key;
+
+       btrfs_set_header_nritems(buf, *slot + 1);
+       (*itemoff) -= sizeof(*dev_extent);
+       btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
+       btrfs_set_disk_key_objectid(&disk_key, 1);
+       btrfs_set_disk_key_offset(&disk_key, start);
+       btrfs_set_item_key(buf, &disk_key, *slot);
+       btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+       btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(*dev_extent));
+
+       dev_extent = btrfs_item_ptr(buf, *slot, struct btrfs_dev_extent);
+       btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
+                                           BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+       btrfs_set_dev_extent_length(buf, dev_extent, len);
+       btrfs_set_dev_extent_chunk_offset(buf, dev_extent, start);
+       btrfs_set_dev_extent_chunk_tree(buf, dev_extent,
+                                       BTRFS_CHUNK_TREE_OBJECTID);
+       (*slot)++;
+}
+
+static int setup_temp_dev_tree(int fd, struct btrfs_mkfs_config *cfg,
+                              u64 sys_chunk_start, u64 meta_chunk_start,
+                              u64 dev_bytenr)
+{
+       struct extent_buffer *buf = NULL;
+       u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+       int slot = 0;
+       int ret;
+
+       /* Must ensure SYS chunk starts before META chunk */
+       if (meta_chunk_start < sys_chunk_start) {
+               error("wrong chunk order: meta < system %llu < %llu",
+                               (unsigned long long)meta_chunk_start,
+                               (unsigned long long)sys_chunk_start);
+               return -EINVAL;
+       }
+       buf = malloc(sizeof(*buf) + cfg->nodesize);
+       if (!buf)
+               return -ENOMEM;
+       ret = setup_temp_extent_buffer(buf, cfg, dev_bytenr,
+                                      BTRFS_DEV_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+       insert_temp_dev_extent(buf, &slot, &itemoff, sys_chunk_start,
+                              BTRFS_MKFS_SYSTEM_GROUP_SIZE);
+       insert_temp_dev_extent(buf, &slot, &itemoff, meta_chunk_start,
+                              BTRFS_CONVERT_META_GROUP_SIZE);
+       ret = write_temp_extent_buffer(fd, buf, dev_bytenr);
+out:
+       free(buf);
+       return ret;
+}
+
+static int setup_temp_fs_tree(int fd, struct btrfs_mkfs_config *cfg,
+                             u64 fs_bytenr)
+{
+       struct extent_buffer *buf = NULL;
+       int ret;
+
+       buf = malloc(sizeof(*buf) + cfg->nodesize);
+       if (!buf)
+               return -ENOMEM;
+       ret = setup_temp_extent_buffer(buf, cfg, fs_bytenr,
+                                      BTRFS_FS_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+       /*
+        * Temporary fs tree is completely empty.
+        */
+       ret = write_temp_extent_buffer(fd, buf, fs_bytenr);
+out:
+       free(buf);
+       return ret;
+}
+
+static int setup_temp_csum_tree(int fd, struct btrfs_mkfs_config *cfg,
+                               u64 csum_bytenr)
+{
+       struct extent_buffer *buf = NULL;
+       int ret;
+
+       buf = malloc(sizeof(*buf) + cfg->nodesize);
+       if (!buf)
+               return -ENOMEM;
+       ret = setup_temp_extent_buffer(buf, cfg, csum_bytenr,
+                                      BTRFS_CSUM_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+       /*
+        * Temporary csum tree is completely empty.
+        */
+       ret = write_temp_extent_buffer(fd, buf, csum_bytenr);
+out:
+       free(buf);
+       return ret;
+}
+
+/*
+ * Insert one temporary extent item.
+ *
+ * NOTE: if skinny_metadata is not enabled, this function must be called
+ * after all other trees are initialized.
+ * Or fs without skinny-metadata will be screwed up.
+ */
+static int insert_temp_extent_item(int fd, struct extent_buffer *buf,
+                                  struct btrfs_mkfs_config *cfg,
+                                  int *slot, u32 *itemoff, u64 bytenr,
+                                  u64 ref_root)
+{
+       struct extent_buffer *tmp;
+       struct btrfs_extent_item *ei;
+       struct btrfs_extent_inline_ref *iref;
+       struct btrfs_disk_key disk_key;
+       struct btrfs_disk_key tree_info_key;
+       struct btrfs_tree_block_info *info;
+       int itemsize;
+       int skinny_metadata = cfg->features &
+                             BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA;
+       int ret;
+
+       if (skinny_metadata)
+               itemsize = sizeof(*ei) + sizeof(*iref);
+       else
+               itemsize = sizeof(*ei) + sizeof(*iref) +
+                          sizeof(struct btrfs_tree_block_info);
+
+       btrfs_set_header_nritems(buf, *slot + 1);
+       *(itemoff) -= itemsize;
+
+       if (skinny_metadata) {
+               btrfs_set_disk_key_type(&disk_key, BTRFS_METADATA_ITEM_KEY);
+               btrfs_set_disk_key_offset(&disk_key, 0);
+       } else {
+               btrfs_set_disk_key_type(&disk_key, BTRFS_EXTENT_ITEM_KEY);
+               btrfs_set_disk_key_offset(&disk_key, cfg->nodesize);
+       }
+       btrfs_set_disk_key_objectid(&disk_key, bytenr);
+
+       btrfs_set_item_key(buf, &disk_key, *slot);
+       btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+       btrfs_set_item_size(buf, btrfs_item_nr(*slot), itemsize);
+
+       ei = btrfs_item_ptr(buf, *slot, struct btrfs_extent_item);
+       btrfs_set_extent_refs(buf, ei, 1);
+       btrfs_set_extent_generation(buf, ei, 1);
+       btrfs_set_extent_flags(buf, ei, BTRFS_EXTENT_FLAG_TREE_BLOCK);
+
+       if (skinny_metadata) {
+               iref = (struct btrfs_extent_inline_ref *)(ei + 1);
+       } else {
+               info = (struct btrfs_tree_block_info *)(ei + 1);
+               iref = (struct btrfs_extent_inline_ref *)(info + 1);
+       }
+       btrfs_set_extent_inline_ref_type(buf, iref,
+                                        BTRFS_TREE_BLOCK_REF_KEY);
+       btrfs_set_extent_inline_ref_offset(buf, iref, ref_root);
+
+       (*slot)++;
+       if (skinny_metadata)
+               return 0;
+
+       /*
+        * Lastly, check the tree block key by read the tree block
+        * Since we do 1:1 mapping for convert case, we can directly
+        * read the bytenr from disk
+        */
+       tmp = malloc(sizeof(*tmp) + cfg->nodesize);
+       if (!tmp)
+               return -ENOMEM;
+       ret = setup_temp_extent_buffer(tmp, cfg, bytenr, ref_root);
+       if (ret < 0)
+               goto out;
+       ret = pread(fd, tmp->data, cfg->nodesize, bytenr);
+       if (ret < cfg->nodesize) {
+               ret = (ret < 0 ? -errno : -EIO);
+               goto out;
+       }
+       if (btrfs_header_nritems(tmp) == 0) {
+               btrfs_set_disk_key_type(&tree_info_key, 0);
+               btrfs_set_disk_key_objectid(&tree_info_key, 0);
+               btrfs_set_disk_key_offset(&tree_info_key, 0);
+       } else {
+               btrfs_item_key(tmp, &tree_info_key, 0);
+       }
+       btrfs_set_tree_block_key(buf, info, &tree_info_key);
+
+out:
+       free(tmp);
+       return ret;
+}
+
+static void insert_temp_block_group(struct extent_buffer *buf,
+                                  struct btrfs_mkfs_config *cfg,
+                                  int *slot, u32 *itemoff,
+                                  u64 bytenr, u64 len, u64 used, u64 flag)
+{
+       struct btrfs_block_group_item bgi;
+       struct btrfs_disk_key disk_key;
+
+       btrfs_set_header_nritems(buf, *slot + 1);
+       (*itemoff) -= sizeof(bgi);
+       btrfs_set_disk_key_type(&disk_key, BTRFS_BLOCK_GROUP_ITEM_KEY);
+       btrfs_set_disk_key_objectid(&disk_key, bytenr);
+       btrfs_set_disk_key_offset(&disk_key, len);
+       btrfs_set_item_key(buf, &disk_key, *slot);
+       btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+       btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(bgi));
+
+       btrfs_set_block_group_flags(&bgi, flag);
+       btrfs_set_block_group_used(&bgi, used);
+       btrfs_set_block_group_chunk_objectid(&bgi,
+                       BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+       write_extent_buffer(buf, &bgi, btrfs_item_ptr_offset(buf, *slot),
+                           sizeof(bgi));
+       (*slot)++;
+}
+
+static int setup_temp_extent_tree(int fd, struct btrfs_mkfs_config *cfg,
+                                 u64 chunk_bytenr, u64 root_bytenr,
+                                 u64 extent_bytenr, u64 dev_bytenr,
+                                 u64 fs_bytenr, u64 csum_bytenr)
+{
+       struct extent_buffer *buf = NULL;
+       u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+       int slot = 0;
+       int ret;
+
+       /*
+        * We must ensure provided bytenr are in ascending order,
+        * or extent tree key order will be broken.
+        */
+       if (!(chunk_bytenr < root_bytenr && root_bytenr < extent_bytenr &&
+             extent_bytenr < dev_bytenr && dev_bytenr < fs_bytenr &&
+             fs_bytenr < csum_bytenr)) {
+               error("bad tree bytenr order: "
+                               "chunk < root %llu < %llu, "
+                               "root < extent %llu < %llu, "
+                               "extent < dev %llu < %llu, "
+                               "dev < fs %llu < %llu, "
+                               "fs < csum %llu < %llu",
+                               (unsigned long long)chunk_bytenr,
+                               (unsigned long long)root_bytenr,
+                               (unsigned long long)root_bytenr,
+                               (unsigned long long)extent_bytenr,
+                               (unsigned long long)extent_bytenr,
+                               (unsigned long long)dev_bytenr,
+                               (unsigned long long)dev_bytenr,
+                               (unsigned long long)fs_bytenr,
+                               (unsigned long long)fs_bytenr,
+                               (unsigned long long)csum_bytenr);
+               return -EINVAL;
+       }
+       buf = malloc(sizeof(*buf) + cfg->nodesize);
+       if (!buf)
+               return -ENOMEM;
+
+       ret = setup_temp_extent_buffer(buf, cfg, extent_bytenr,
+                                      BTRFS_EXTENT_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+
+       ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+                       chunk_bytenr, BTRFS_CHUNK_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+
+       insert_temp_block_group(buf, cfg, &slot, &itemoff, chunk_bytenr,
+                       BTRFS_MKFS_SYSTEM_GROUP_SIZE, cfg->nodesize,
+                       BTRFS_BLOCK_GROUP_SYSTEM);
+
+       ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+                       root_bytenr, BTRFS_ROOT_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+
+       /* 5 tree block used, root, extent, dev, fs and csum*/
+       insert_temp_block_group(buf, cfg, &slot, &itemoff, root_bytenr,
+                       BTRFS_CONVERT_META_GROUP_SIZE, cfg->nodesize * 5,
+                       BTRFS_BLOCK_GROUP_METADATA);
+
+       ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+                       extent_bytenr, BTRFS_EXTENT_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+       ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+                       dev_bytenr, BTRFS_DEV_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+       ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+                       fs_bytenr, BTRFS_FS_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+       ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+                       csum_bytenr, BTRFS_CSUM_TREE_OBJECTID);
+       if (ret < 0)
+               goto out;
+
+       ret = write_temp_extent_buffer(fd, buf, extent_bytenr);
+out:
+       free(buf);
+       return ret;
+}
+
+/*
+ * Improved version of make_btrfs().
+ *
+ * This one will
+ * 1) Do chunk allocation to avoid used data
+ *    And after this function, extent type matches chunk type
+ * 2) Better structured code
+ *    No super long hand written codes to initialized all tree blocks
+ *    Split into small blocks and reuse codes.
+ *    TODO: Reuse tree operation facilities by introducing new flags
+ */
+int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
+                             struct btrfs_convert_context *cctx)
+{
+       struct cache_tree *free = &cctx->free;
+       struct cache_tree *used = &cctx->used;
+       u64 sys_chunk_start;
+       u64 meta_chunk_start;
+       /* chunk tree bytenr, in system chunk */
+       u64 chunk_bytenr;
+       /* metadata trees bytenr, in metadata chunk */
+       u64 root_bytenr;
+       u64 extent_bytenr;
+       u64 dev_bytenr;
+       u64 fs_bytenr;
+       u64 csum_bytenr;
+       int ret;
+
+       /* Shouldn't happen */
+       BUG_ON(cache_tree_empty(used));
+
+       /*
+        * reserve space for temporary superblock first
+        * Here we allocate a little larger space, to keep later
+        * free space will be STRIPE_LEN aligned
+        */
+       ret = reserve_free_space(free, BTRFS_STRIPE_LEN,
+                                &cfg->super_bytenr);
+       if (ret < 0)
+               goto out;
+
+       /*
+        * Then reserve system chunk space
+        * TODO: Change system group size depending on cctx->total_bytes.
+        * If using current 4M, it can only handle less than one TB for
+        * worst case and then run out of sys space.
+        */
+       ret = reserve_free_space(free, BTRFS_MKFS_SYSTEM_GROUP_SIZE,
+                                &sys_chunk_start);
+       if (ret < 0)
+               goto out;
+       ret = reserve_free_space(free, BTRFS_CONVERT_META_GROUP_SIZE,
+                                &meta_chunk_start);
+       if (ret < 0)
+               goto out;
+
+       /*
+        * Allocated meta/sys chunks will be mapped 1:1 with device offset.
+        *
+        * Inside the allocated metadata chunk, the layout will be:
+        *  | offset            | contents      |
+        *  -------------------------------------
+        *  | +0                | tree root     |
+        *  | +nodesize         | extent root   |
+        *  | +nodesize * 2     | device root   |
+        *  | +nodesize * 3     | fs tree       |
+        *  | +nodesize * 4     | csum tree     |
+        *  -------------------------------------
+        * Inside the allocated system chunk, the layout will be:
+        *  | offset            | contents      |
+        *  -------------------------------------
+        *  | +0                | chunk root    |
+        *  -------------------------------------
+        */
+       chunk_bytenr = sys_chunk_start;
+       root_bytenr = meta_chunk_start;
+       extent_bytenr = meta_chunk_start + cfg->nodesize;
+       dev_bytenr = meta_chunk_start + cfg->nodesize * 2;
+       fs_bytenr = meta_chunk_start + cfg->nodesize * 3;
+       csum_bytenr = meta_chunk_start + cfg->nodesize * 4;
+
+       ret = setup_temp_super(fd, cfg, root_bytenr, chunk_bytenr);
+       if (ret < 0)
+               goto out;
+
+       ret = setup_temp_root_tree(fd, cfg, root_bytenr, extent_bytenr,
+                                  dev_bytenr, fs_bytenr, csum_bytenr);
+       if (ret < 0)
+               goto out;
+       ret = setup_temp_chunk_tree(fd, cfg, sys_chunk_start, meta_chunk_start,
+                                   chunk_bytenr);
+       if (ret < 0)
+               goto out;
+       ret = setup_temp_dev_tree(fd, cfg, sys_chunk_start, meta_chunk_start,
+                                 dev_bytenr);
+       if (ret < 0)
+               goto out;
+       ret = setup_temp_fs_tree(fd, cfg, fs_bytenr);
+       if (ret < 0)
+               goto out;
+       ret = setup_temp_csum_tree(fd, cfg, csum_bytenr);
+       if (ret < 0)
+               goto out;
+       /*
+        * Setup extent tree last, since it may need to read tree block key
+        * for non-skinny metadata case.
+        */
+       ret = setup_temp_extent_tree(fd, cfg, chunk_bytenr, root_bytenr,
+                                    extent_bytenr, dev_bytenr, fs_bytenr,
+                                    csum_bytenr);
+out:
+       return ret;
+}
+
+/*
  * @fs_uuid - if NULL, generates a UUID, returns back the new filesystem UUID
+ *
+ * The superblock signature is not valid, denotes a partially created
+ * filesystem, needs to be finalized.
  */
 int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 {
@@ -216,29 +1089,27 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
        memset(&super, 0, sizeof(super));
 
        num_bytes = (cfg->num_bytes / cfg->sectorsize) * cfg->sectorsize;
-       if (cfg->fs_uuid && *cfg->fs_uuid) {
+       if (*cfg->fs_uuid) {
                if (uuid_parse(cfg->fs_uuid, super.fsid) != 0) {
-                       fprintf(stderr, "could not parse UUID: %s\n",
-                               cfg->fs_uuid);
+                       error("cannot not parse UUID: %s", cfg->fs_uuid);
                        ret = -EINVAL;
                        goto out;
                }
                if (!test_uuid_unique(cfg->fs_uuid)) {
-                       fprintf(stderr, "non-unique UUID: %s\n", cfg->fs_uuid);
+                       error("non-unique UUID: %s", cfg->fs_uuid);
                        ret = -EBUSY;
                        goto out;
                }
        } else {
                uuid_generate(super.fsid);
-               if (cfg->fs_uuid)
-                       uuid_unparse(super.fsid, cfg->fs_uuid);
+               uuid_unparse(super.fsid, cfg->fs_uuid);
        }
        uuid_generate(super.dev_item.uuid);
        uuid_generate(chunk_tree_uuid);
 
        btrfs_set_super_bytenr(&super, cfg->blocks[0]);
        btrfs_set_super_num_devices(&super, 1);
-       btrfs_set_super_magic(&super, BTRFS_MAGIC);
+       btrfs_set_super_magic(&super, BTRFS_MAGIC_PARTIAL);
        btrfs_set_super_generation(&super, 1);
        btrfs_set_super_root(&super, cfg->blocks[1]);
        btrfs_set_super_chunk_root(&super, cfg->blocks[3]);
@@ -352,8 +1223,21 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
                if (!skinny_metadata)
                        item_size += sizeof(struct btrfs_tree_block_info);
 
-               BUG_ON(cfg->blocks[i] < first_free);
-               BUG_ON(cfg->blocks[i] < cfg->blocks[i - 1]);
+               if (cfg->blocks[i] < first_free) {
+                       error("block[%d] below first free: %llu < %llu",
+                                       i, (unsigned long long)cfg->blocks[i],
+                                       (unsigned long long)first_free);
+                       ret = -EINVAL;
+                       goto out;
+               }
+               if (cfg->blocks[i] < cfg->blocks[i - 1]) {
+                       error("blocks %d and %d in reverse order: %llu < %llu",
+                               i, i - 1,
+                               (unsigned long long)cfg->blocks[i],
+                               (unsigned long long)cfg->blocks[i - 1]);
+                       ret = -EINVAL;
+                       goto out;
+               }
 
                /* create extent item */
                itemoff -= item_size;
@@ -553,7 +1437,6 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
        }
 
        /* and write out the super block */
-       BUG_ON(sizeof(super) > cfg->sectorsize);
        memset(buf->data, 0, BTRFS_SUPER_INFO_SIZE);
        memcpy(buf->data, &super, sizeof(super));
        buf->len = BTRFS_SUPER_INFO_SIZE;
@@ -571,20 +1454,65 @@ out:
        return ret;
 }
 
+#define VERSION_TO_STRING3(a,b,c)      #a "." #b "." #c, KERNEL_VERSION(a,b,c)
+#define VERSION_TO_STRING2(a,b)                #a "." #b, KERNEL_VERSION(a,b,0)
+
+/*
+ * Feature stability status and versions: compat <= safe <= default
+ */
 static const struct btrfs_fs_feature {
        const char *name;
        u64 flag;
+       const char *sysfs_name;
+       /*
+        * Compatibility with kernel of given version. Filesystem can be
+        * mounted.
+        */
+       const char *compat_str;
+       u32 compat_ver;
+       /*
+        * Considered safe for use, but is not on by default, even if the
+        * kernel supports the feature.
+        */
+       const char *safe_str;
+       u32 safe_ver;
+       /*
+        * Considered safe for use and will be turned on by default if
+        * supported by the running kernel.
+        */
+       const char *default_str;
+       u32 default_ver;
        const char *desc;
 } mkfs_features[] = {
        { "mixed-bg", BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS,
+               "mixed_groups",
+               VERSION_TO_STRING3(2,6,37),
+               VERSION_TO_STRING3(2,6,37),
+               NULL, 0,
                "mixed data and metadata block groups" },
        { "extref", BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF,
+               "extended_iref",
+               VERSION_TO_STRING2(3,7),
+               VERSION_TO_STRING2(3,12),
+               VERSION_TO_STRING2(3,12),
                "increased hardlink limit per file to 65536" },
        { "raid56", BTRFS_FEATURE_INCOMPAT_RAID56,
+               "raid56",
+               VERSION_TO_STRING2(3,9),
+               NULL, 0,
+               NULL, 0,
                "raid56 extended format" },
        { "skinny-metadata", BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA,
+               "skinny_metadata",
+               VERSION_TO_STRING2(3,10),
+               VERSION_TO_STRING2(3,18),
+               VERSION_TO_STRING2(3,18),
                "reduced-size metadata extent refs" },
        { "no-holes", BTRFS_FEATURE_INCOMPAT_NO_HOLES,
+               "no_holes",
+               VERSION_TO_STRING2(3,14),
+               VERSION_TO_STRING2(4,0),
+               NULL, 0,
                "no explicit hole extents for files" },
        /* Keep this one last */
        { "list-all", BTRFS_FEATURE_LIST_ALL, NULL }
@@ -643,17 +1571,19 @@ void btrfs_list_all_fs_features(u64 mask_disallowed)
 
        fprintf(stderr, "Filesystem features available:\n");
        for (i = 0; i < ARRAY_SIZE(mkfs_features) - 1; i++) {
-               char *is_default = "";
+               const struct btrfs_fs_feature *feat = &mkfs_features[i];
 
-               if (mkfs_features[i].flag & mask_disallowed)
+               if (feat->flag & mask_disallowed)
                        continue;
-               if (mkfs_features[i].flag & BTRFS_MKFS_DEFAULT_FEATURES)
-                       is_default = ", default";
-               fprintf(stderr, "%-20s- %s (0x%llx%s)\n",
-                               mkfs_features[i].name,
-                               mkfs_features[i].desc,
-                               mkfs_features[i].flag,
-                               is_default);
+               fprintf(stderr, "%-20s- %s (0x%llx", feat->name, feat->desc,
+                               feat->flag);
+               if (feat->compat_ver)
+                       fprintf(stderr, ", compat=%s", feat->compat_str);
+               if (feat->safe_ver)
+                       fprintf(stderr, ", safe=%s", feat->safe_str);
+               if (feat->default_ver)
+                       fprintf(stderr, ", default=%s", feat->default_str);
+               fprintf(stderr, ")\n");
        }
 }
 
@@ -676,6 +1606,53 @@ char* btrfs_parse_fs_features(char *namelist, u64 *flags)
        return NULL;
 }
 
+void print_kernel_version(FILE *stream, u32 version)
+{
+       u32 v[3];
+
+       v[0] = version & 0xFF;
+       v[1] = (version >> 8) & 0xFF;
+       v[2] = version >> 16;
+       fprintf(stream, "%u.%u", v[2], v[1]);
+       if (v[0])
+               fprintf(stream, ".%u", v[0]);
+}
+
+u32 get_running_kernel_version(void)
+{
+       struct utsname utsbuf;
+       char *tmp;
+       char *saveptr = NULL;
+       u32 version;
+
+       uname(&utsbuf);
+       if (strcmp(utsbuf.sysname, "Linux") != 0) {
+               error("unsupported system: %s", utsbuf.sysname);
+               exit(1);
+       }
+       /* 1.2.3-4-name */
+       tmp = strchr(utsbuf.release, '-');
+       if (tmp)
+               *tmp = 0;
+
+       tmp = strtok_r(utsbuf.release, ".", &saveptr);
+       if (!string_is_numerical(tmp))
+               return (u32)-1;
+       version = atoi(tmp) << 16;
+       tmp = strtok_r(NULL, ".", &saveptr);
+       if (!string_is_numerical(tmp))
+               return (u32)-1;
+       version |= atoi(tmp) << 8;
+       tmp = strtok_r(NULL, ".", &saveptr);
+       if (tmp) {
+               if (!string_is_numerical(tmp))
+                       return (u32)-1;
+               version |= atoi(tmp);
+       }
+
+       return version;
+}
+
 u64 btrfs_device_size(int fd, struct stat *st)
 {
        u64 size;
@@ -727,7 +1704,7 @@ static int zero_dev_clamped(int fd, off_t start, ssize_t len, u64 dev_size)
 }
 
 int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
-                     struct btrfs_root *root, int fd, char *path,
+                     struct btrfs_root *root, int fd, const char *path,
                      u64 device_total_bytes, u32 io_width, u32 io_align,
                      u32 sectorsize)
 {
@@ -742,13 +1719,16 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
 
        device_total_bytes = (device_total_bytes / sectorsize) * sectorsize;
 
-       device = kzalloc(sizeof(*device), GFP_NOFS);
-       if (!device)
-               goto err_nomem;
-       buf = kzalloc(sectorsize, GFP_NOFS);
-       if (!buf)
-               goto err_nomem;
-       BUG_ON(sizeof(*disk_super) > sectorsize);
+       device = calloc(1, sizeof(*device));
+       if (!device) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       buf = calloc(1, sectorsize);
+       if (!buf) {
+               ret = -ENOMEM;
+               goto out;
+       }
 
        disk_super = (struct btrfs_super_block *)buf;
        dev_item = &disk_super->dev_item;
@@ -766,12 +1746,15 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
        device->total_ios = 0;
        device->dev_root = root->fs_info->dev_root;
        device->name = strdup(path);
-       if (!device->name)
-               goto err_nomem;
+       if (!device->name) {
+               ret = -ENOMEM;
+               goto out;
+       }
 
        INIT_LIST_HEAD(&device->dev_list);
        ret = btrfs_add_device(trans, root, device);
-       BUG_ON(ret);
+       if (ret)
+               goto out;
 
        fs_total_bytes = btrfs_super_total_bytes(super) + device_total_bytes;
        btrfs_set_super_total_bytes(super, fs_total_bytes);
@@ -794,15 +1777,15 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
        ret = pwrite(fd, buf, sectorsize, BTRFS_SUPER_INFO_OFFSET);
        BUG_ON(ret != sectorsize);
 
-       kfree(buf);
+       free(buf);
        list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
        device->fs_devices = root->fs_info->fs_devices;
        return 0;
 
-err_nomem:
-       kfree(device);
-       kfree(buf);
-       return -ENOMEM;
+out:
+       free(device);
+       free(buf);
+       return ret;
 }
 
 static int btrfs_wipe_existing_sb(int fd)
@@ -856,8 +1839,8 @@ out:
        return ret;
 }
 
-int btrfs_prepare_device(int fd, const char *file, int zero_end,
-               u64 *block_count_ret, u64 max_block_count, int discard)
+int btrfs_prepare_device(int fd, const char *file, u64 *block_count_ret,
+               u64 max_block_count, unsigned opflags)
 {
        u64 block_count;
        struct stat st;
@@ -877,15 +1860,16 @@ int btrfs_prepare_device(int fd, const char *file, int zero_end,
        if (max_block_count)
                block_count = min(block_count, max_block_count);
 
-       if (discard) {
+       if (opflags & PREP_DEVICE_DISCARD) {
                /*
                 * We intentionally ignore errors from the discard ioctl.  It
                 * is not necessary for the mkfs functionality but just an
                 * optimization.
                 */
                if (discard_range(fd, 0, 0) == 0) {
-                       printf("Performing full device TRIM (%s) ...\n",
-                               pretty_size(block_count));
+                       if (opflags & PREP_DEVICE_VERBOSE)
+                               printf("Performing full device TRIM %s (%s) ...\n",
+                                               file, pretty_size(block_count));
                        discard_blocks(fd, 0, block_count);
                }
        }
@@ -894,7 +1878,7 @@ int btrfs_prepare_device(int fd, const char *file, int zero_end,
        for (i = 0 ; !ret && i < BTRFS_SUPER_MIRROR_MAX; i++)
                ret = zero_dev_clamped(fd, btrfs_sb_offset(i),
                                       BTRFS_SUPER_INFO_SIZE, block_count);
-       if (!ret && zero_end)
+       if (!ret && (opflags & PREP_DEVICE_ZERO_END))
                ret = zero_dev_clamped(fd, block_count - ZERO_DEV_BYTES,
                                       ZERO_DEV_BYTES, block_count);
 
@@ -932,7 +1916,7 @@ int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
        btrfs_set_stack_timespec_nsec(&inode_item.ctime, 0);
        btrfs_set_stack_timespec_sec(&inode_item.mtime, now);
        btrfs_set_stack_timespec_nsec(&inode_item.mtime, 0);
-       btrfs_set_stack_timespec_sec(&inode_item.otime, 0);
+       btrfs_set_stack_timespec_sec(&inode_item.otime, now);
        btrfs_set_stack_timespec_nsec(&inode_item.otime, 0);
 
        if (root->fs_info->tree_root == root)
@@ -1445,12 +2429,12 @@ int check_mounted_where(int fd, const char *file, char *where, int size,
 
        /* scan the initial device */
        ret = btrfs_scan_one_device(fd, file, &fs_devices_mnt,
-                                   &total_devs, BTRFS_SUPER_INFO_OFFSET, 0);
+                   &total_devs, BTRFS_SUPER_INFO_OFFSET, SBREAD_DEFAULT);
        is_btrfs = (ret >= 0);
 
        /* scan other devices */
        if (is_btrfs && total_devs > 1) {
-               ret = btrfs_scan_lblkid();
+               ret = btrfs_scan_devices();
                if (ret)
                        return ret;
        }
@@ -1530,7 +2514,7 @@ int btrfs_register_one_device(const char *fname)
 
 /*
  * Register all devices in the fs_uuid list created in the user
- * space. Ensure btrfs_scan_lblkid() is called before this func.
+ * space. Ensure btrfs_scan_devices() is called before this func.
  */
 int btrfs_register_all_devices(void)
 {
@@ -1573,7 +2557,12 @@ int btrfs_device_already_in_root(struct btrfs_root *root, int fd,
 
        ret = 0;
        disk_super = (struct btrfs_super_block *)buf;
-       if (btrfs_super_magic(disk_super) != BTRFS_MAGIC)
+       /*
+        * Accept devices from the same filesystem, allow partially created
+        * structures.
+        */
+       if (btrfs_super_magic(disk_super) != BTRFS_MAGIC &&
+                       btrfs_super_magic(disk_super) != BTRFS_MAGIC_PARTIAL)
                goto brelse;
 
        if (!memcmp(disk_super->fsid, root->fs_info->super_copy->fsid,
@@ -1616,12 +2605,19 @@ int pretty_size_snprintf(u64 size, char *str, size_t str_size, unsigned unit_mod
        int mult = 0;
        const char** suffix = NULL;
        u64 last_size;
+       int negative;
 
        if (str_size == 0)
                return 0;
 
+       negative = !!(unit_mode & UNITS_NEGATIVE);
+       unit_mode &= ~UNITS_NEGATIVE;
+
        if ((unit_mode & ~UNITS_MODE_MASK) == UNITS_RAW) {
-               snprintf(str, str_size, "%llu", size);
+               if (negative)
+                       snprintf(str, str_size, "%lld", size);
+               else
+                       snprintf(str, str_size, "%llu", size);
                return 0;
        }
 
@@ -1656,10 +2652,22 @@ int pretty_size_snprintf(u64 size, char *str, size_t str_size, unsigned unit_mod
                           num_divs = 0;
                           break;
        default:
-               while (size >= mult) {
-                       last_size = size;
-                       size /= mult;
-                       num_divs++;
+               if (negative) {
+                       s64 ssize = (s64)size;
+                       s64 last_ssize = ssize;
+
+                       while ((ssize < 0 ? -ssize : ssize) >= mult) {
+                               last_ssize = ssize;
+                               ssize /= mult;
+                               num_divs++;
+                       }
+                       last_size = (u64)last_ssize;
+               } else {
+                       while (size >= mult) {
+                               last_size = size;
+                               size /= mult;
+                               num_divs++;
+                       }
                }
                /*
                 * If the value is smaller than base, we didn't do any
@@ -1677,7 +2685,12 @@ int pretty_size_snprintf(u64 size, char *str, size_t str_size, unsigned unit_mod
                assert(0);
                return -1;
        }
-       fraction = (float)last_size / base;
+
+       if (negative) {
+               fraction = (float)(s64)last_size / base;
+       } else {
+               fraction = (float)last_size / base;
+       }
 
        return snprintf(str, str_size, "%.2f%s", fraction, suffix[num_divs]);
 }
@@ -1713,8 +2726,8 @@ static int check_label(const char *input)
        int len = strlen(input);
 
        if (len > BTRFS_LABEL_SIZE - 1) {
-               fprintf(stderr, "ERROR: Label %s is too long (max %d)\n",
-                       input, BTRFS_LABEL_SIZE - 1);
+               error("label %s is too long (max %d)", input,
+                               BTRFS_LABEL_SIZE - 1);
                return -1;
        }
 
@@ -1729,12 +2742,11 @@ static int set_label_unmounted(const char *dev, const char *label)
 
        ret = check_mounted(dev);
        if (ret < 0) {
-              fprintf(stderr, "FATAL: error checking %s mount status\n", dev);
+              error("checking mount status of %s failed: %d", dev, ret);
               return -1;
        }
        if (ret > 0) {
-               fprintf(stderr, "ERROR: dev %s is mounted, use mount point\n",
-                       dev);
+               error("device %s is mounted, use mount point", dev);
                return -1;
        }
 
@@ -1762,15 +2774,15 @@ static int set_label_mounted(const char *mount_path, const char *labelp)
 
        fd = open(mount_path, O_RDONLY | O_NOATIME);
        if (fd < 0) {
-               fprintf(stderr, "ERROR: unable to access '%s'\n", mount_path);
+               error("unable to access %s: %s", mount_path, strerror(errno));
                return -1;
        }
 
        memset(label, 0, sizeof(label));
        __strncpy_null(label, labelp, BTRFS_LABEL_SIZE - 1);
        if (ioctl(fd, BTRFS_IOC_SET_FSLABEL, label) < 0) {
-               fprintf(stderr, "ERROR: unable to set label %s\n",
-                       strerror(errno));
+               error("unable to set label of %s: %s", mount_path,
+                               strerror(errno));
                close(fd);
                return -1;
        }
@@ -1786,7 +2798,7 @@ int get_label_unmounted(const char *dev, char *label)
 
        ret = check_mounted(dev);
        if (ret < 0) {
-              fprintf(stderr, "FATAL: error checking %s mount status\n", dev);
+              error("checking mount status of %s failed: %d", dev, ret);
               return -1;
        }
 
@@ -1818,7 +2830,7 @@ int get_label_mounted(const char *mount_path, char *labelp)
 
        fd = open(mount_path, O_RDONLY | O_NOATIME);
        if (fd < 0) {
-               fprintf(stderr, "ERROR: unable to access '%s'\n", mount_path);
+               error("unable to access %s: %s", mount_path, strerror(errno));
                return -1;
        }
 
@@ -1826,7 +2838,7 @@ int get_label_mounted(const char *mount_path, char *labelp)
        ret = ioctl(fd, BTRFS_IOC_GET_FSLABEL, label);
        if (ret < 0) {
                if (errno != ENOTTY)
-                       fprintf(stderr, "ERROR: unable to get label %s\n",
+                       error("unable to get label of %s: %s", mount_path,
                                        strerror(errno));
                ret = -errno;
                close(fd);
@@ -1889,21 +2901,20 @@ u64 parse_size(char *s)
        u64 ret;
 
        if (!s) {
-               fprintf(stderr, "ERROR: Size value is empty\n");
+               error("size value is empty");
                exit(1);
        }
        if (s[0] == '-') {
-               fprintf(stderr,
-                       "ERROR: Size value '%s' is less equal than 0\n", s);
+               error("size value '%s' is less equal than 0", s);
                exit(1);
        }
        ret = strtoull(s, &endptr, 10);
        if (endptr == s) {
-               fprintf(stderr, "ERROR: Size value '%s' is invalid\n", s);
+               error("size value '%s' is invalid", s);
                exit(1);
        }
        if (endptr[0] && endptr[1]) {
-               fprintf(stderr, "ERROR: Illegal suffix contains character '%c' in wrong position\n",
+               error("illegal suffix contains character '%c' in wrong position",
                        endptr[1]);
                exit(1);
        }
@@ -1912,8 +2923,7 @@ u64 parse_size(char *s)
         * need to call strtoull to get the real size
         */
        if (errno == ERANGE && ret == ULLONG_MAX) {
-               fprintf(stderr,
-                       "ERROR: Size value '%s' is too large for u64\n", s);
+               error("size value '%s' is too large for u64", s);
                exit(1);
        }
        if (endptr[0]) {
@@ -1940,15 +2950,13 @@ u64 parse_size(char *s)
                case 'b':
                        break;
                default:
-                       fprintf(stderr, "ERROR: Unknown size descriptor '%c'\n",
-                               c);
+                       error("unknown size descriptor '%c'", c);
                        exit(1);
                }
        }
        /* Check whether ret * mult overflow */
        if (fls64(ret) + fls64(mult) - 1 > 64) {
-               fprintf(stderr,
-                       "ERROR: Size value '%s' is too large for u64\n", s);
+               error("size value '%s' is too large for u64", s);
                exit(1);
        }
        ret *= mult;
@@ -1993,14 +3001,16 @@ path:
        fd = open(p, O_RDONLY);
        if (fd < 0)
                goto err;
-       ret = lookup_ino_rootid(fd, &id);
+       ret = lookup_path_rootid(fd, &id);
+       if (ret)
+               error("failed to lookup root id: %s", strerror(-ret));
        close(fd);
        if (ret < 0)
                goto err;
        return id;
 
 err:
-       fprintf(stderr, "ERROR: invalid qgroupid or subvolume path: %s\n", p);
+       error("invalid qgroupid or subvolume path: %s", p);
        exit(-1);
 }
 
@@ -2143,13 +3153,13 @@ again:
  *
  * Returns 0 on success, or a negative errno.
  */
-int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
+int get_fs_info(const char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                struct btrfs_ioctl_dev_info_args **di_ret)
 {
        int fd = -1;
        int ret = 0;
        int ndevs = 0;
-       int i = 0;
+       u64 last_devid = 0;
        int replacing = 0;
        struct btrfs_fs_devices *fs_devices_mnt = NULL;
        struct btrfs_ioctl_dev_info_args *di_args;
@@ -2162,7 +3172,6 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
        if (is_block_device(path) == 1) {
                struct btrfs_super_block *disk_super;
                char buf[BTRFS_SUPER_INFO_SIZE];
-               u64 devid;
 
                /* Ensure it's mounted, then set path to the mountpoint */
                fd = open(path, O_RDONLY);
@@ -2190,10 +3199,8 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                        ret = -EIO;
                        goto out;
                }
-               devid = btrfs_stack_device_id(&disk_super->dev_item);
-
-               fi_args->max_id = devid;
-               i = devid;
+               last_devid = btrfs_stack_device_id(&disk_super->dev_item);
+               fi_args->max_id = last_devid;
 
                memcpy(fi_args->fsid, fs_devices_mnt->fsid, BTRFS_FSID_SIZE);
                close(fd);
@@ -2230,8 +3237,8 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                        fi_args->num_devices++;
                        ndevs++;
                        replacing = 1;
-                       if (i == 0)
-                               i++;
+                       if (last_devid == 0)
+                               last_devid++;
                }
        }
 
@@ -2246,8 +3253,8 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
 
        if (replacing)
                memcpy(di_args, &tmp, sizeof(tmp));
-       for (; i <= fi_args->max_id; ++i) {
-               ret = get_device_info(fd, i, &di_args[ndevs]);
+       for (; last_devid <= fi_args->max_id; last_devid++) {
+               ret = get_device_info(fd, last_devid, &di_args[ndevs]);
                if (ret == -ENODEV)
                        continue;
                if (ret)
@@ -2445,6 +3452,7 @@ int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
        u64 dev_cnt, int mixed, int ssd)
 {
        u64 allowed = 0;
+       u64 profile = metadata_profile | data_profile;
 
        switch (dev_cnt) {
        default:
@@ -2459,8 +3467,7 @@ int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
                allowed |= BTRFS_BLOCK_GROUP_DUP;
        }
 
-       if (dev_cnt > 1 &&
-           ((metadata_profile | data_profile) & BTRFS_BLOCK_GROUP_DUP)) {
+       if (dev_cnt > 1 && profile & BTRFS_BLOCK_GROUP_DUP) {
                warning("DUP is not recommended on filesystem with multiple devices");
        }
        if (metadata_profile & ~allowed) {
@@ -2480,6 +3487,12 @@ int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
                return 1;
        }
 
+       if (dev_cnt == 3 && profile & BTRFS_BLOCK_GROUP_RAID6) {
+               warning("RAID6 is not recommended on filesystem with 3 devices only");
+       }
+       if (dev_cnt == 2 && profile & BTRFS_BLOCK_GROUP_RAID5) {
+               warning("RAID5 is not recommended on filesystem with 2 devices only");
+       }
        warning_on(!mixed && (data_profile & BTRFS_BLOCK_GROUP_DUP) && ssd,
                   "DUP may not actually lead to 2 copies on the device, see manual page");
 
@@ -2517,45 +3530,43 @@ int test_dev_for_mkfs(const char *file, int force_overwrite)
 
        ret = is_swap_device(file);
        if (ret < 0) {
-               fprintf(stderr, "ERROR: checking status of %s: %s\n", file,
-                       strerror(-ret));
+               error("checking status of %s: %s", file, strerror(-ret));
                return 1;
        }
        if (ret == 1) {
-               fprintf(stderr, "ERROR: %s is a swap device\n", file);
+               error("%s is a swap device", file);
                return 1;
        }
        if (!force_overwrite) {
                if (check_overwrite(file)) {
-                       fprintf(stderr, "Use the -f option to force overwrite.\n");
+                       error("use the -f option to force overwrite of %s",
+                                       file);
                        return 1;
                }
        }
        ret = check_mounted(file);
        if (ret < 0) {
-               fprintf(stderr, "ERROR: checking mount status of %s: %s\n",
-                       file, strerror(-ret));
+               error("cannot check mount status of %s: %s", file,
+                               strerror(-ret));
                return 1;
        }
        if (ret == 1) {
-               fprintf(stderr, "ERROR: %s is mounted\n", file);
+               error("%s is mounted", file);
                return 1;
        }
        /* check if the device is busy */
        fd = open(file, O_RDWR|O_EXCL);
        if (fd < 0) {
-               fprintf(stderr, "ERROR: unable to open %s: %s\n", file,
-                       strerror(errno));
+               error("unable to open %s: %s", file, strerror(errno));
                return 1;
        }
        if (fstat(fd, &st)) {
-               fprintf(stderr, "ERROR: unable to stat %s: %s\n", file,
-                       strerror(errno));
+               error("unable to stat %s: %s", file, strerror(errno));
                close(fd);
                return 1;
        }
        if (!S_ISBLK(st.st_mode)) {
-               fprintf(stderr, "ERROR: %s is not a block device\n", file);
+               error("%s is not a block device", file);
                close(fd);
                return 1;
        }
@@ -2563,7 +3574,7 @@ int test_dev_for_mkfs(const char *file, int force_overwrite)
        return 0;
 }
 
-int btrfs_scan_lblkid(void)
+int btrfs_scan_devices(void)
 {
        int fd = -1;
        int ret;
@@ -2578,7 +3589,7 @@ int btrfs_scan_lblkid(void)
                return 0;
 
        if (blkid_get_cache(&cache, NULL) < 0) {
-               printf("ERROR: lblkid cache get failed\n");
+               error("blkid cache get failed");
                return 1;
        }
        blkid_probe_all(cache);
@@ -2593,13 +3604,14 @@ int btrfs_scan_lblkid(void)
 
                fd = open(path, O_RDONLY);
                if (fd < 0) {
-                       printf("ERROR: could not open %s\n", path);
+                       error("cannot open %s: %s", path, strerror(errno));
                        continue;
                }
                ret = btrfs_scan_one_device(fd, path, &tmp_devices,
-                               &num_devices, BTRFS_SUPER_INFO_OFFSET, 0);
+                               &num_devices, BTRFS_SUPER_INFO_OFFSET,
+                               SBREAD_DEFAULT);
                if (ret) {
-                       printf("ERROR: could not scan %s\n", path);
+                       error("cannot scan %s: %s", path, strerror(-ret));
                        close (fd);
                        continue;
                }
@@ -2662,34 +3674,6 @@ int ask_user(const char *question)
 }
 
 /*
- * For a given:
- * - file or directory return the containing tree root id
- * - subvolume return its own tree id
- * - BTRFS_EMPTY_SUBVOL_DIR_OBJECTID (directory with ino == 2) the result is
- *   undefined and function returns -1
- */
-int lookup_ino_rootid(int fd, u64 *rootid)
-{
-       struct btrfs_ioctl_ino_lookup_args args;
-       int ret;
-
-       memset(&args, 0, sizeof(args));
-       args.treeid = 0;
-       args.objectid = BTRFS_FIRST_FREE_OBJECTID;
-
-       ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
-       if (ret < 0) {
-               fprintf(stderr, "ERROR: Failed to lookup root id - %s\n",
-                       strerror(errno));
-               return ret;
-       }
-
-       *rootid = args.treeid;
-
-       return 0;
-}
-
-/*
  * return 0 if a btrfs mount point is found
  * return 1 if a mount point is found but not btrfs
  * return <0 if something goes wrong
@@ -2888,6 +3872,10 @@ u64 get_partition_size(const char *dev)
        return result;
 }
 
+/*
+ * Check if the BTRFS_IOC_TREE_SEARCH_V2 ioctl is supported on a given
+ * filesystem, opened at fd
+ */
 int btrfs_tree_search2_ioctl_supported(int fd)
 {
        struct btrfs_ioctl_search_args_v2 *args2;
@@ -2895,10 +3883,6 @@ int btrfs_tree_search2_ioctl_supported(int fd)
        int args2_size = 1024;
        char args2_buf[args2_size];
        int ret;
-       static int v2_supported = -1;
-
-       if (v2_supported != -1)
-               return v2_supported;
 
        args2 = (struct btrfs_ioctl_search_args_v2 *)args2_buf;
        sk = &(args2->key);
@@ -2919,36 +3903,29 @@ int btrfs_tree_search2_ioctl_supported(int fd)
        args2->buf_size = args2_size - sizeof(struct btrfs_ioctl_search_args_v2);
        ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH_V2, args2);
        if (ret == -EOPNOTSUPP)
-               v2_supported = 0;
+               return 0;
        else if (ret == 0)
-               v2_supported = 1;
-       else
-               return ret;
-
-       return v2_supported;
+               return 1;
+       return ret;
 }
 
 int btrfs_check_nodesize(u32 nodesize, u32 sectorsize, u64 features)
 {
        if (nodesize < sectorsize) {
-               fprintf(stderr,
-                       "ERROR: Illegal nodesize %u (smaller than %u)\n",
-                       nodesize, sectorsize);
+               error("illegal nodesize %u (smaller than %u)",
+                               nodesize, sectorsize);
                return -1;
        } else if (nodesize > BTRFS_MAX_METADATA_BLOCKSIZE) {
-               fprintf(stderr,
-                       "ERROR: Illegal nodesize %u (larger than %u)\n",
+               error("illegal nodesize %u (larger than %u)",
                        nodesize, BTRFS_MAX_METADATA_BLOCKSIZE);
                return -1;
        } else if (nodesize & (sectorsize - 1)) {
-               fprintf(stderr,
-                       "ERROR: Illegal nodesize %u (not aligned to %u)\n",
+               error("illegal nodesize %u (not aligned to %u)",
                        nodesize, sectorsize);
                return -1;
        } else if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS &&
                   nodesize != sectorsize) {
-               fprintf(stderr,
-                       "ERROR: Illegal nodesize %u (not equal to %u for mixed block group)\n",
+               error("illegal nodesize %u (not equal to %u for mixed block group)",
                        nodesize, sectorsize);
                return -1;
        }
@@ -3081,6 +4058,8 @@ unsigned int get_unit_mode_from_arg(int *argc, char *argv[], int df_mode)
 
 int string_is_numerical(const char *str)
 {
+       if (!str)
+               return 0;
        if (!(*str >= '0' && *str <= '9'))
                return 0;
        while (*str >= '0' && *str <= '9')
@@ -3116,6 +4095,24 @@ void clean_args_no_options(int argc, char *argv[], const char * const *usagestr)
        }
 }
 
+/*
+ * Same as clean_args_no_options but pass through arguments that could look
+ * like short options. Eg. reisze which takes a negative resize argument like
+ * '-123M' .
+ *
+ * This accepts only two forms:
+ * - "-- option1 option2 ..."
+ * - "option1 option2 ..."
+ */
+void clean_args_no_options_relaxed(int argc, char *argv[], const char * const *usagestr)
+{
+       if (argc <= 1)
+               return;
+
+       if (strcmp(argv[1], "--") == 0)
+               optind = 2;
+}
+
 /* Subvolume helper functions */
 /*
  * test if name is a correct subvolume name
@@ -3209,27 +4206,20 @@ int get_subvol_info(const char *fullpath, struct root_info *get_ri)
                goto out;
 
        ret = btrfs_list_get_path_rootid(fd, &sv_id);
-       if (ret) {
-               error("can't get rootid for '%s'", fullpath);
+       if (ret)
                goto out;
-       }
 
        mntfd = btrfs_open_dir(mnt, &dirstream2, 1);
        if (mntfd < 0)
                goto out;
 
-       if (sv_id == BTRFS_FS_TREE_OBJECTID) {
-               ret = 2;
-               /*
-                * So that caller may decide if thats an error or just fine.
-                */
-               goto out;
-       }
-
        memset(get_ri, 0, sizeof(*get_ri));
        get_ri->root_id = sv_id;
 
-       ret = btrfs_get_subvol(mntfd, get_ri);
+       if (sv_id == BTRFS_FS_TREE_OBJECTID)
+               ret = btrfs_get_toplevel_subvol(mntfd, get_ri);
+       else
+               ret = btrfs_get_subvol(mntfd, get_ri);
        if (ret)
                error("can't find '%s': %d", svpath, ret);
 
@@ -3240,3 +4230,66 @@ out:
 
        return ret;
 }
+
+void init_rand_seed(u64 seed)
+{
+       int i;
+
+       /* only use the last 48 bits */
+       for (i = 0; i < 3; i++) {
+               rand_seed[i] = (unsigned short)(seed ^ (unsigned short)(-1));
+               seed >>= 16;
+       }
+       rand_seed_initlized = 1;
+}
+
+static void __init_seed(void)
+{
+       struct timeval tv;
+       int ret;
+       int fd;
+
+       if(rand_seed_initlized)
+               return;
+       /* Use urandom as primary seed source. */
+       fd = open("/dev/urandom", O_RDONLY);
+       if (fd >= 0) {
+               ret = read(fd, rand_seed, sizeof(rand_seed));
+               close(fd);
+               if (ret < sizeof(rand_seed))
+                       goto fallback;
+       } else {
+fallback:
+               /* Use time and pid as fallback seed */
+               warning("failed to read /dev/urandom, use time and pid as random seed");
+               gettimeofday(&tv, 0);
+               rand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
+               rand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
+               rand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
+       }
+       rand_seed_initlized = 1;
+}
+
+u32 rand_u32(void)
+{
+       __init_seed();
+       /*
+        * Don't use nrand48, its range is [0,2^31) The highest bit will alwasy
+        * be 0.  Use jrand48 to include the highest bit.
+        */
+       return (u32)jrand48(rand_seed);
+}
+
+unsigned int rand_range(unsigned int upper)
+{
+       __init_seed();
+       /*
+        * Use the full 48bits to mod, which would be more uniformly
+        * distributed
+        */
+       return (unsigned int)(jrand48(rand_seed) % upper);
+}
+
+void btrfs_config_init(void)
+{
+}