Block groups can be balanced and relocated. Today the relocation happens
by following back references and forcing COW on all of the extents
that live inside a given block group.
Other the long term relocation code will be added that blindly shifts
extents around without changing their logical addresses. That way it won't
have to follow the backreferences at all.
This code has the advantage of heavily testing the backrefs, and it
can restripe into new RAID levels. When two or more snapshots
have references on an extent, the extent is COW'd only once and all
of the reference holders are updated to point to the new location.
Signed-off-by: Chris Mason <chris.mason@xxxxxxxxxx>
--- a/fs/btrfs/extent-tree.c 2009-01-08 09:56:07.321458970 -0500
+++ b/fs/btrfs/extent-tree.c 2009-01-08 09:50:24.557586920 -0500
@@ -1881,6 +1881,54 @@
return flags;
}
+static int do_chunk_alloc(struct btrfs_trans_handle *trans,
+ struct btrfs_root *extent_root, u64 alloc_bytes,
+ u64 flags, int force)
+{
+ struct btrfs_space_info *space_info;
+ u64 thresh;
+ int ret = 0;
+
+ mutex_lock(&extent_root->fs_info->chunk_mutex);
+
+ flags = btrfs_reduce_alloc_profile(extent_root, flags);
+
+ space_info = __find_space_info(extent_root->fs_info, flags);
+ if (!space_info) {
+ ret = update_space_info(extent_root->fs_info, flags,
+ 0, 0, &space_info);
+ BUG_ON(ret);
+ }
+ BUG_ON(!space_info);
+
+ spin_lock(&space_info->lock);
+ if (space_info->force_alloc) {
+ force = 1;
+ space_info->force_alloc = 0;
+ }
+ if (space_info->full) {
+ spin_unlock(&space_info->lock);
+ goto out;
+ }
+
+ thresh = space_info->total_bytes - space_info->bytes_readonly;
+ thresh = div_factor(thresh, 6);
+ if (!force &&
+ (space_info->bytes_used + space_info->bytes_pinned +
+ space_info->bytes_reserved + alloc_bytes) < thresh) {
+ spin_unlock(&space_info->lock);
+ goto out;
+ }
+ spin_unlock(&space_info->lock);
+
+ ret = btrfs_alloc_chunk(trans, extent_root, flags);
+ if (ret)
+ space_info->full = 1;
+out:
+ mutex_unlock(&extent_root->fs_info->chunk_mutex);
+ return ret;
+}
+
static int update_block_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 bytenr, u64 num_bytes, int alloc,
@@ -3829,3 +3877,2110 @@
return ret;
}
+int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *node,
+ struct extent_buffer *parent)
+{
+ struct btrfs_path *path;
+ int level;
+ int parent_level;
+ int ret = 0;
+ int wret;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+
+ BUG_ON(!btrfs_tree_locked(parent));
+ parent_level = btrfs_header_level(parent);
+ extent_buffer_get(parent);
+ path->nodes[parent_level] = parent;
+ path->slots[parent_level] = btrfs_header_nritems(parent);
+
+ BUG_ON(!btrfs_tree_locked(node));
+ level = btrfs_header_level(node);
+ extent_buffer_get(node);
+ path->nodes[level] = node;
+ path->slots[level] = 0;
+
+ while (1) {
+ wret = walk_down_subtree(trans, root, path, &level);
+ if (wret < 0)
+ ret = wret;
+ if (wret != 0)
+ break;
+
+ wret = walk_up_tree(trans, root, path, &level, parent_level);
+ if (wret < 0)
+ ret = wret;
+ if (wret != 0)
+ break;
+ }
+
+ btrfs_free_path(path);
+ return ret;
+}
+
+static unsigned long calc_ra(unsigned long start, unsigned long last,
+ unsigned long nr)
+{
+ return min(last, start + nr - 1);
+}
+
+static noinline int relocate_inode_pages(struct inode *inode, u64 start,
+ u64 len)
+{
+ u64 page_start;
+ u64 page_end;
+ unsigned long first_index;
+ unsigned long last_index;
+ unsigned long i;
+ struct page *page;
+ struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+ struct file_ra_state *ra;
+ struct btrfs_ordered_extent *ordered;
+ unsigned int total_read = 0;
+ unsigned int total_dirty = 0;
+ int ret = 0;
+
+ ra = kzalloc(sizeof(*ra), GFP_NOFS);
+
+ mutex_lock(&inode->i_mutex);
+ first_index = start >> PAGE_CACHE_SHIFT;
+ last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
+
+ /* make sure the dirty trick played by the caller work */
+ ret = invalidate_inode_pages2_range(inode->i_mapping,
+ first_index, last_index);
+ if (ret)
+ goto out_unlock;
+
+ file_ra_state_init(ra, inode->i_mapping);
+
+ for (i = first_index ; i <= last_index; i++) {
+ if (total_read % ra->ra_pages == 0) {
+ btrfs_force_ra(inode->i_mapping, ra, NULL, i,
+ calc_ra(i, last_index, ra->ra_pages));
+ }
+ total_read++;
+again:
+ if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
+ BUG_ON(1);
+ page = grab_cache_page(inode->i_mapping, i);
+ if (!page) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+ if (!PageUptodate(page)) {
+ btrfs_readpage(NULL, page);
+ lock_page(page);
+ if (!PageUptodate(page)) {
+ unlock_page(page);
+ page_cache_release(page);
+ ret = -EIO;
+ goto out_unlock;
+ }
+ }
+ wait_on_page_writeback(page);
+
+ page_start = (u64)page->index << PAGE_CACHE_SHIFT;
+ page_end = page_start + PAGE_CACHE_SIZE - 1;
+ lock_extent(io_tree, page_start, page_end, GFP_NOFS);
+
+ ordered = btrfs_lookup_ordered_extent(inode, page_start);
+ if (ordered) {
+ unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+ unlock_page(page);
+ page_cache_release(page);
+ btrfs_start_ordered_extent(inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ goto again;
+ }
+ set_page_extent_mapped(page);
+
+ if (i == first_index)
+ set_extent_bits(io_tree, page_start, page_end,
+ EXTENT_BOUNDARY, GFP_NOFS);
+ btrfs_set_extent_delalloc(inode, page_start, page_end);
+
+ set_page_dirty(page);
+ total_dirty++;
+
+ unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+
+out_unlock:
+ kfree(ra);
+ mutex_unlock(&inode->i_mutex);
+ balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
+ return ret;
+}
+
+static noinline int relocate_data_extent(struct inode *reloc_inode,
+ struct btrfs_key *extent_key,
+ u64 offset)
+{
+ struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
+ struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
+ struct extent_map *em;
+ u64 start = extent_key->objectid - offset;
+ u64 end = start + extent_key->offset - 1;
+
+ em = alloc_extent_map(GFP_NOFS);
+ BUG_ON(!em || IS_ERR(em));
+
+ em->start = start;
+ em->len = extent_key->offset;
+ em->block_len = extent_key->offset;
+ em->block_start = extent_key->objectid;
+ em->bdev = root->fs_info->fs_devices->latest_bdev;
+ set_bit(EXTENT_FLAG_PINNED, &em->flags);
+
+ /* setup extent map to cheat btrfs_readpage */
+ lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
+ while (1) {
+ int ret;
+ spin_lock(&em_tree->lock);
+ ret = add_extent_mapping(em_tree, em);
+ spin_unlock(&em_tree->lock);
+ if (ret != -EEXIST) {
+ free_extent_map(em);
+ break;
+ }
+ btrfs_drop_extent_cache(reloc_inode, start, end, 0);
+ }
+ unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
+
+ return relocate_inode_pages(reloc_inode, start, extent_key->offset);
+}
+
+struct btrfs_ref_path {
+ u64 extent_start;
+ u64 nodes[BTRFS_MAX_LEVEL];
+ u64 root_objectid;
+ u64 root_generation;
+ u64 owner_objectid;
+ u32 num_refs;
+ int lowest_level;
+ int current_level;
+ int shared_level;
+
+ struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
+ u64 new_nodes[BTRFS_MAX_LEVEL];
+};
+
+struct disk_extent {
+ u64 ram_bytes;
+ u64 disk_bytenr;
+ u64 disk_num_bytes;
+ u64 offset;
+ u64 num_bytes;
+ u8 compression;
+ u8 encryption;
+ u16 other_encoding;
+};
+
+static int is_cowonly_root(u64 root_objectid)
+{
+ if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
+ root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
+ root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
+ root_objectid == BTRFS_DEV_TREE_OBJECTID ||
+ root_objectid == BTRFS_TREE_LOG_OBJECTID ||
+ root_objectid == BTRFS_CSUM_TREE_OBJECTID)
+ return 1;
+ return 0;
+}
+
+static noinline int __next_ref_path(struct btrfs_trans_handle *trans,
+ struct btrfs_root *extent_root,
+ struct btrfs_ref_path *ref_path,
+ int first_time)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_path *path;
+ struct btrfs_extent_ref *ref;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ u64 bytenr;
+ u32 nritems;
+ int level;
+ int ret = 1;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ if (first_time) {
+ ref_path->lowest_level = -1;
+ ref_path->current_level = -1;
+ ref_path->shared_level = -1;
+ goto walk_up;
+ }
+walk_down:
+ level = ref_path->current_level - 1;
+ while (level >= -1) {
+ u64 parent;
+ if (level < ref_path->lowest_level)
+ break;
+
+ if (level >= 0)
+ bytenr = ref_path->nodes[level];
+ else
+ bytenr = ref_path->extent_start;
+ BUG_ON(bytenr == 0);
+
+ parent = ref_path->nodes[level + 1];
+ ref_path->nodes[level + 1] = 0;
+ ref_path->current_level = level;
+ BUG_ON(parent == 0);
+
+ key.objectid = bytenr;
+ key.offset = parent + 1;
+ key.type = BTRFS_EXTENT_REF_KEY;
+
+ ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret == 0);
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(extent_root, path);
+ if (ret < 0)
+ goto out;
+ if (ret > 0)
+ goto next;
+ leaf = path->nodes[0];
+ }
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.objectid == bytenr &&
+ found_key.type == BTRFS_EXTENT_REF_KEY) {
+ if (level < ref_path->shared_level)
+ ref_path->shared_level = level;
+ goto found;
+ }
+next:
+ level--;
+ btrfs_release_path(extent_root, path);
+ cond_resched();
+ }
+ /* reached lowest level */
+ ret = 1;
+ goto out;
+walk_up:
+ level = ref_path->current_level;
+ while (level < BTRFS_MAX_LEVEL - 1) {
+ u64 ref_objectid;
+
+ if (level >= 0)
+ bytenr = ref_path->nodes[level];
+ else
+ bytenr = ref_path->extent_start;
+
+ BUG_ON(bytenr == 0);
+
+ key.objectid = bytenr;
+ key.offset = 0;
+ key.type = BTRFS_EXTENT_REF_KEY;
+
+ ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(extent_root, path);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ /* the extent was freed by someone */
+ if (ref_path->lowest_level == level)
+ goto out;
+ btrfs_release_path(extent_root, path);
+ goto walk_down;
+ }
+ leaf = path->nodes[0];
+ }
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.objectid != bytenr ||
+ found_key.type != BTRFS_EXTENT_REF_KEY) {
+ /* the extent was freed by someone */
+ if (ref_path->lowest_level == level) {
+ ret = 1;
+ goto out;
+ }
+ btrfs_release_path(extent_root, path);
+ goto walk_down;
+ }
+found:
+ ref = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_ref);
+ ref_objectid = btrfs_ref_objectid(leaf, ref);
+ if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
+ if (first_time) {
+ level = (int)ref_objectid;
+ BUG_ON(level >= BTRFS_MAX_LEVEL);
+ ref_path->lowest_level = level;
+ ref_path->current_level = level;
+ ref_path->nodes[level] = bytenr;
+ } else {
+ WARN_ON(ref_objectid != level);
+ }
+ } else {
+ WARN_ON(level != -1);
+ }
+ first_time = 0;
+
+ if (ref_path->lowest_level == level) {
+ ref_path->owner_objectid = ref_objectid;
+ ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
+ }
+
+ /*
+ * the block is tree root or the block isn't in reference
+ * counted tree.
+ */
+ if (found_key.objectid == found_key.offset ||
+ is_cowonly_root(btrfs_ref_root(leaf, ref))) {
+ ref_path->root_objectid = btrfs_ref_root(leaf, ref);
+ ref_path->root_generation =
+ btrfs_ref_generation(leaf, ref);
+ if (level < 0) {
+ /* special reference from the tree log */
+ ref_path->nodes[0] = found_key.offset;
+ ref_path->current_level = 0;
+ }
+ ret = 0;
+ goto out;
+ }
+
+ level++;
+ BUG_ON(ref_path->nodes[level] != 0);
+ ref_path->nodes[level] = found_key.offset;
+ ref_path->current_level = level;
+
+ /*
+ * the reference was created in the running transaction,
+ * no need to continue walking up.
+ */
+ if (btrfs_ref_generation(leaf, ref) == trans->transid) {
+ ref_path->root_objectid = btrfs_ref_root(leaf, ref);
+ ref_path->root_generation =
+ btrfs_ref_generation(leaf, ref);
+ ret = 0;
+ goto out;
+ }
+
+ btrfs_release_path(extent_root, path);
+ cond_resched();
+ }
+ /* reached max tree level, but no tree root found. */
+ BUG();
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
+ struct btrfs_root *extent_root,
+ struct btrfs_ref_path *ref_path,
+ u64 extent_start)
+{
+ memset(ref_path, 0, sizeof(*ref_path));
+ ref_path->extent_start = extent_start;
+
+ return __next_ref_path(trans, extent_root, ref_path, 1);
+}
+
+static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
+ struct btrfs_root *extent_root,
+ struct btrfs_ref_path *ref_path)
+{
+ return __next_ref_path(trans, extent_root, ref_path, 0);
+}
+
+static noinline int get_new_locations(struct inode *reloc_inode,
+ struct btrfs_key *extent_key,
+ u64 offset, int no_fragment,
+ struct disk_extent **extents,
+ int *nr_extents)
+{
+ struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
+ struct btrfs_path *path;
+ struct btrfs_file_extent_item *fi;
+ struct extent_buffer *leaf;
+ struct disk_extent *exts = *extents;
+ struct btrfs_key found_key;
+ u64 cur_pos;
+ u64 last_byte;
+ u32 nritems;
+ int nr = 0;
+ int max = *nr_extents;
+ int ret;
+
+ WARN_ON(!no_fragment && *extents);
+ if (!exts) {
+ max = 1;
+ exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
+ if (!exts)
+ return -ENOMEM;
+ }
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+
+ cur_pos = extent_key->objectid - offset;
+ last_byte = extent_key->objectid + extent_key->offset;
+ ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
+ cur_pos, 0);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ while (1) {
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto out;
+ if (ret > 0)
+ break;
+ leaf = path->nodes[0];
+ }
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.offset != cur_pos ||
+ found_key.type != BTRFS_EXTENT_DATA_KEY ||
+ found_key.objectid != reloc_inode->i_ino)
+ break;
+
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) !=
+ BTRFS_FILE_EXTENT_REG ||
+ btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
+ break;
+
+ if (nr == max) {
+ struct disk_extent *old = exts;
+ max *= 2;
+ exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
+ memcpy(exts, old, sizeof(*exts) * nr);
+ if (old != *extents)
+ kfree(old);
+ }
+
+ exts[nr].disk_bytenr =
+ btrfs_file_extent_disk_bytenr(leaf, fi);
+ exts[nr].disk_num_bytes =
+ btrfs_file_extent_disk_num_bytes(leaf, fi);
+ exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
+ exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+ exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
+ exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
+ exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
+ exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
+ fi);
+ BUG_ON(exts[nr].offset > 0);
+ BUG_ON(exts[nr].compression || exts[nr].encryption);
+ BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
+
+ cur_pos += exts[nr].num_bytes;
+ nr++;
+
+ if (cur_pos + offset >= last_byte)
+ break;
+
+ if (no_fragment) {
+ ret = 1;
+ goto out;
+ }
+ path->slots[0]++;
+ }
+
+ BUG_ON(cur_pos + offset > last_byte);
+ if (cur_pos + offset < last_byte) {
+ ret = -ENOENT;
+ goto out;
+ }
+ ret = 0;
+out:
+ btrfs_free_path(path);
+ if (ret) {
+ if (exts != *extents)
+ kfree(exts);
+ } else {
+ *extents = exts;
+ *nr_extents = nr;
+ }
+ return ret;
+}
+
+static noinline int replace_one_extent(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *extent_key,
+ struct btrfs_key *leaf_key,
+ struct btrfs_ref_path *ref_path,
+ struct disk_extent *new_extents,
+ int nr_extents)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_file_extent_item *fi;
+ struct inode *inode = NULL;
+ struct btrfs_key key;
+ u64 lock_start = 0;
+ u64 lock_end = 0;
+ u64 num_bytes;
+ u64 ext_offset;
+ u64 first_pos;
+ u32 nritems;
+ int nr_scaned = 0;
+ int extent_locked = 0;
+ int extent_type;
+ int ret;
+
+ memcpy(&key, leaf_key, sizeof(key));
+ first_pos = INT_LIMIT(loff_t) - extent_key->offset;
+ if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
+ if (key.objectid < ref_path->owner_objectid ||
+ (key.objectid == ref_path->owner_objectid &&
+ key.type < BTRFS_EXTENT_DATA_KEY)) {
+ key.objectid = ref_path->owner_objectid;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = 0;
+ }
+ }
+
+ while (1) {
+ ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+ if (ret < 0)
+ goto out;
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+next:
+ if (extent_locked && ret > 0) {
+ /*
+ * the file extent item was modified by someone
+ * before the extent got locked.
+ */
+ unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
+ lock_end, GFP_NOFS);
+ extent_locked = 0;
+ }
+
+ if (path->slots[0] >= nritems) {
+ if (++nr_scaned > 2)
+ break;
+
+ BUG_ON(extent_locked);
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto out;
+ if (ret > 0)
+ break;
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
+ if ((key.objectid > ref_path->owner_objectid) ||
+ (key.objectid == ref_path->owner_objectid &&
+ key.type > BTRFS_EXTENT_DATA_KEY) ||
+ (key.offset >= first_pos + extent_key->offset))
+ break;
+ }
+
+ if (inode && key.objectid != inode->i_ino) {
+ BUG_ON(extent_locked);
+ btrfs_release_path(root, path);
+ mutex_unlock(&inode->i_mutex);
+ iput(inode);
+ inode = NULL;
+ continue;
+ }
+
+ if (key.type != BTRFS_EXTENT_DATA_KEY) {
+ path->slots[0]++;
+ ret = 1;
+ goto next;
+ }
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ extent_type = btrfs_file_extent_type(leaf, fi);
+ if ((extent_type != BTRFS_FILE_EXTENT_REG &&
+ extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
+ (btrfs_file_extent_disk_bytenr(leaf, fi) !=
+ extent_key->objectid)) {
+ path->slots[0]++;
+ ret = 1;
+ goto next;
+ }
+
+ num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+ ext_offset = btrfs_file_extent_offset(leaf, fi);
+
+ if (first_pos > key.offset - ext_offset)
+ first_pos = key.offset - ext_offset;
+
+ if (!extent_locked) {
+ lock_start = key.offset;
+ lock_end = lock_start + num_bytes - 1;
+ } else {
+ if (lock_start > key.offset ||
+ lock_end + 1 < key.offset + num_bytes) {
+ unlock_extent(&BTRFS_I(inode)->io_tree,
+ lock_start, lock_end, GFP_NOFS);
+ extent_locked = 0;
+ }
+ }
+
+ if (!inode) {
+ btrfs_release_path(root, path);
+
+ inode = btrfs_iget_locked(root->fs_info->sb,
+ key.objectid, root);
+ if (inode->i_state & I_NEW) {
+ BTRFS_I(inode)->root = root;
+ BTRFS_I(inode)->location.objectid =
+ key.objectid;
+ BTRFS_I(inode)->location.type =
+ BTRFS_INODE_ITEM_KEY;
+ BTRFS_I(inode)->location.offset = 0;
+ btrfs_read_locked_inode(inode);
+ unlock_new_inode(inode);
+ }
+ /*
+ * some code call btrfs_commit_transaction while
+ * holding the i_mutex, so we can't use mutex_lock
+ * here.
+ */
+ if (is_bad_inode(inode) ||
+ !mutex_trylock(&inode->i_mutex)) {
+ iput(inode);
+ inode = NULL;
+ key.offset = (u64)-1;
+ goto skip;
+ }
+ }
+
+ if (!extent_locked) {
+ struct btrfs_ordered_extent *ordered;
+
+ btrfs_release_path(root, path);
+
+ lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
+ lock_end, GFP_NOFS);
+ ordered = btrfs_lookup_first_ordered_extent(inode,
+ lock_end);
+ if (ordered &&
+ ordered->file_offset <= lock_end &&
+ ordered->file_offset + ordered->len > lock_start) {
+ unlock_extent(&BTRFS_I(inode)->io_tree,
+ lock_start, lock_end, GFP_NOFS);
+ btrfs_start_ordered_extent(inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ key.offset += num_bytes;
+ goto skip;
+ }
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+
+ extent_locked = 1;
+ continue;
+ }
+
+ if (nr_extents == 1) {
+ /* update extent pointer in place */
+ btrfs_set_file_extent_disk_bytenr(leaf, fi,
+ new_extents[0].disk_bytenr);
+ btrfs_set_file_extent_disk_num_bytes(leaf, fi,
+ new_extents[0].disk_num_bytes);
+ btrfs_mark_buffer_dirty(leaf);
+
+ btrfs_drop_extent_cache(inode, key.offset,
+ key.offset + num_bytes - 1, 0);
+
+ ret = btrfs_inc_extent_ref(trans, root,
+ new_extents[0].disk_bytenr,
+ new_extents[0].disk_num_bytes,
+ leaf->start,
+ root->root_key.objectid,
+ trans->transid,
+ key.objectid);
+ BUG_ON(ret);
+
+ ret = btrfs_free_extent(trans, root,
+ extent_key->objectid,
+ extent_key->offset,
+ leaf->start,
+ btrfs_header_owner(leaf),
+ btrfs_header_generation(leaf),
+ key.objectid, 0);
+ BUG_ON(ret);
+
+ btrfs_release_path(root, path);
+ key.offset += num_bytes;
+ } else {
+ BUG_ON(1);
+#if 0
+ u64 alloc_hint;
+ u64 extent_len;
+ int i;
+ /*
+ * drop old extent pointer at first, then insert the
+ * new pointers one bye one
+ */
+ btrfs_release_path(root, path);
+ ret = btrfs_drop_extents(trans, root, inode, key.offset,
+ key.offset + num_bytes,
+ key.offset, &alloc_hint);
+ BUG_ON(ret);
+
+ for (i = 0; i < nr_extents; i++) {
+ if (ext_offset >= new_extents[i].num_bytes) {
+ ext_offset -= new_extents[i].num_bytes;
+ continue;
+ }
+ extent_len = min(new_extents[i].num_bytes -
+ ext_offset, num_bytes);
+
+ ret = btrfs_insert_empty_item(trans, root,
+ path, &key,
+ sizeof(*fi));
+ BUG_ON(ret);
+
+ leaf = path->nodes[0];
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_generation(leaf, fi,
+ trans->transid);
+ btrfs_set_file_extent_type(leaf, fi,
+ BTRFS_FILE_EXTENT_REG);
+ btrfs_set_file_extent_disk_bytenr(leaf, fi,
+ new_extents[i].disk_bytenr);
+ btrfs_set_file_extent_disk_num_bytes(leaf, fi,
+ new_extents[i].disk_num_bytes);
+ btrfs_set_file_extent_ram_bytes(leaf, fi,
+ new_extents[i].ram_bytes);
+
+ btrfs_set_file_extent_compression(leaf, fi,
+ new_extents[i].compression);
+ btrfs_set_file_extent_encryption(leaf, fi,
+ new_extents[i].encryption);
+ btrfs_set_file_extent_other_encoding(leaf, fi,
+ new_extents[i].other_encoding);
+
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ extent_len);
+ ext_offset += new_extents[i].offset;
+ btrfs_set_file_extent_offset(leaf, fi,
+ ext_offset);
+ btrfs_mark_buffer_dirty(leaf);
+
+ btrfs_drop_extent_cache(inode, key.offset,
+ key.offset + extent_len - 1, 0);
+
+ ret = btrfs_inc_extent_ref(trans, root,
+ new_extents[i].disk_bytenr,
+ new_extents[i].disk_num_bytes,
+ leaf->start,
+ root->root_key.objectid,
+ trans->transid, key.objectid);
+ BUG_ON(ret);
+ btrfs_release_path(root, path);
+
+ inode_add_bytes(inode, extent_len);
+
+ ext_offset = 0;
+ num_bytes -= extent_len;
+ key.offset += extent_len;
+
+ if (num_bytes == 0)
+ break;
+ }
+ BUG_ON(i >= nr_extents);
+#endif
+ }
+
+ if (extent_locked) {
+ unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
+ lock_end, GFP_NOFS);
+ extent_locked = 0;
+ }
+skip:
+ if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
+ key.offset >= first_pos + extent_key->offset)
+ break;
+
+ cond_resched();
+ }
+ ret = 0;
+out:
+ btrfs_release_path(root, path);
+ if (inode) {
+ mutex_unlock(&inode->i_mutex);
+ if (extent_locked) {
+ unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
+ lock_end, GFP_NOFS);
+ }
+ iput(inode);
+ }
+ return ret;
+}
+
+int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf, u64 orig_start)
+{
+ int level;
+ int ret;
+
+ BUG_ON(btrfs_header_generation(buf) != trans->transid);
+ BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
+
+ level = btrfs_header_level(buf);
+ if (level == 0) {
+ struct btrfs_leaf_ref *ref;
+ struct btrfs_leaf_ref *orig_ref;
+
+ orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
+ if (!orig_ref)
+ return -ENOENT;
+
+ ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
+ if (!ref) {
+ btrfs_free_leaf_ref(root, orig_ref);
+ return -ENOMEM;
+ }
+
+ ref->nritems = orig_ref->nritems;
+ memcpy(ref->extents, orig_ref->extents,
+ sizeof(ref->extents[0]) * ref->nritems);
+
+ btrfs_free_leaf_ref(root, orig_ref);
+
+ ref->root_gen = trans->transid;
+ ref->bytenr = buf->start;
+ ref->owner = btrfs_header_owner(buf);
+ ref->generation = btrfs_header_generation(buf);
+ ret = btrfs_add_leaf_ref(root, ref, 0);
+ WARN_ON(ret);
+ btrfs_free_leaf_ref(root, ref);
+ }
+ return 0;
+}
+
+static noinline int invalidate_extent_cache(struct btrfs_root *root,
+ struct extent_buffer *leaf,
+ struct btrfs_block_group_cache *group,
+ struct btrfs_root *target_root)
+{
+ struct btrfs_key key;
+ struct inode *inode = NULL;
+ struct btrfs_file_extent_item *fi;
+ u64 num_bytes;
+ u64 skip_objectid = 0;
+ u32 nritems;
+ u32 i;
+
+ nritems = btrfs_header_nritems(leaf);
+ for (i = 0; i < nritems; i++) {
+ btrfs_item_key_to_cpu(leaf, &key, i);
+ if (key.objectid == skip_objectid ||
+ key.type != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE)
+ continue;
+ if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
+ continue;
+ if (!inode || inode->i_ino != key.objectid) {
+ iput(inode);
+ inode = btrfs_ilookup(target_root->fs_info->sb,
+ key.objectid, target_root, 1);
+ }
+ if (!inode) {
+ skip_objectid = key.objectid;
+ continue;
+ }
+ num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+
+ lock_extent(&BTRFS_I(inode)->io_tree, key.offset,
+ key.offset + num_bytes - 1, GFP_NOFS);
+ btrfs_drop_extent_cache(inode, key.offset,
+ key.offset + num_bytes - 1, 1);
+ unlock_extent(&BTRFS_I(inode)->io_tree, key.offset,
+ key.offset + num_bytes - 1, GFP_NOFS);
+ cond_resched();
+ }
+ iput(inode);
+ return 0;
+}
+
+static noinline int replace_extents_in_leaf(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *leaf,
+ struct btrfs_block_group_cache *group,
+ struct inode *reloc_inode)
+{
+ struct btrfs_key key;
+ struct btrfs_key extent_key;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_leaf_ref *ref;
+ struct disk_extent *new_extent;
+ u64 bytenr;
+ u64 num_bytes;
+ u32 nritems;
+ u32 i;
+ int ext_index;
+ int nr_extent;
+ int ret;
+
+ new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
+ BUG_ON(!new_extent);
+
+ ref = btrfs_lookup_leaf_ref(root, leaf->start);
+ BUG_ON(!ref);
+
+ ext_index = -1;
+ nritems = btrfs_header_nritems(leaf);
+ for (i = 0; i < nritems; i++) {
+ btrfs_item_key_to_cpu(leaf, &key, i);
+ if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE)
+ continue;
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ if (bytenr == 0)
+ continue;
+
+ ext_index++;
+ if (bytenr >= group->key.objectid + group->key.offset ||
+ bytenr + num_bytes <= group->key.objectid)
+ continue;
+
+ extent_key.objectid = bytenr;
+ extent_key.offset = num_bytes;
+ extent_key.type = BTRFS_EXTENT_ITEM_KEY;
+ nr_extent = 1;
+ ret = get_new_locations(reloc_inode, &extent_key,
+ group->key.objectid, 1,
+ &new_extent, &nr_extent);
+ if (ret > 0)
+ continue;
+ BUG_ON(ret < 0);
+
+ BUG_ON(ref->extents[ext_index].bytenr != bytenr);
+ BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
+ ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
+ ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
+
+ btrfs_set_file_extent_disk_bytenr(leaf, fi,
+ new_extent->disk_bytenr);
+ btrfs_set_file_extent_disk_num_bytes(leaf, fi,
+ new_extent->disk_num_bytes);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = btrfs_inc_extent_ref(trans, root,
+ new_extent->disk_bytenr,
+ new_extent->disk_num_bytes,
+ leaf->start,
+ root->root_key.objectid,
+ trans->transid, key.objectid);
+ BUG_ON(ret);
+ ret = btrfs_free_extent(trans, root,
+ bytenr, num_bytes, leaf->start,
+ btrfs_header_owner(leaf),
+ btrfs_header_generation(leaf),
+ key.objectid, 0);
+ BUG_ON(ret);
+ cond_resched();
+ }
+ kfree(new_extent);
+ BUG_ON(ext_index + 1 != ref->nritems);
+ btrfs_free_leaf_ref(root, ref);
+ return 0;
+}
+
+int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root)
+{
+ struct btrfs_root *reloc_root;
+ int ret;
+
+ if (root->reloc_root) {
+ reloc_root = root->reloc_root;
+ root->reloc_root = NULL;
+ list_add(&reloc_root->dead_list,
+ &root->fs_info->dead_reloc_roots);
+
+ btrfs_set_root_bytenr(&reloc_root->root_item,
+ reloc_root->node->start);
+ btrfs_set_root_level(&root->root_item,
+ btrfs_header_level(reloc_root->node));
+ memset(&reloc_root->root_item.drop_progress, 0,
+ sizeof(struct btrfs_disk_key));
+ reloc_root->root_item.drop_level = 0;
+
+ ret = btrfs_update_root(trans, root->fs_info->tree_root,
+ &reloc_root->root_key,
+ &reloc_root->root_item);
+ BUG_ON(ret);
+ }
+ return 0;
+}
+
+int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *reloc_root;
+ struct btrfs_root *prev_root = NULL;
+ struct list_head dead_roots;
+ int ret;
+ unsigned long nr;
+
+ INIT_LIST_HEAD(&dead_roots);
+ list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
+
+ while (!list_empty(&dead_roots)) {
+ reloc_root = list_entry(dead_roots.prev,
+ struct btrfs_root, dead_list);
+ list_del_init(&reloc_root->dead_list);
+
+ BUG_ON(reloc_root->commit_root != NULL);
+ while (1) {
+ trans = btrfs_join_transaction(root, 1);
+ BUG_ON(!trans);
+
+ mutex_lock(&root->fs_info->drop_mutex);
+ ret = btrfs_drop_snapshot(trans, reloc_root);
+ if (ret != -EAGAIN)
+ break;
+ mutex_unlock(&root->fs_info->drop_mutex);
+
+ nr = trans->blocks_used;
+ ret = btrfs_end_transaction(trans, root);
+ BUG_ON(ret);
+ btrfs_btree_balance_dirty(root, nr);
+ }
+
+ free_extent_buffer(reloc_root->node);
+
+ ret = btrfs_del_root(trans, root->fs_info->tree_root,
+ &reloc_root->root_key);
+ BUG_ON(ret);
+ mutex_unlock(&root->fs_info->drop_mutex);
+
+ nr = trans->blocks_used;
+ ret = btrfs_end_transaction(trans, root);
+ BUG_ON(ret);
+ btrfs_btree_balance_dirty(root, nr);
+
+ kfree(prev_root);
+ prev_root = reloc_root;
+ }
+ if (prev_root) {
+ btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
+ kfree(prev_root);
+ }
+ return 0;
+}
+
+int btrfs_add_dead_reloc_root(struct btrfs_root *root)
+{
+ list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
+ return 0;
+}
+
+int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
+{
+ struct btrfs_root *reloc_root;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_key location;
+ int found;
+ int ret;
+
+ mutex_lock(&root->fs_info->tree_reloc_mutex);
+ ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
+ BUG_ON(ret);
+ found = !list_empty(&root->fs_info->dead_reloc_roots);
+ mutex_unlock(&root->fs_info->tree_reloc_mutex);
+
+ if (found) {
+ trans = btrfs_start_transaction(root, 1);
+ BUG_ON(!trans);
+ ret = btrfs_commit_transaction(trans, root);
+ BUG_ON(ret);
+ }
+
+ location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
+ location.offset = (u64)-1;
+ location.type = BTRFS_ROOT_ITEM_KEY;
+
+ reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
+ BUG_ON(!reloc_root);
+ btrfs_orphan_cleanup(reloc_root);
+ return 0;
+}
+
+static noinline int init_reloc_tree(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root)
+{
+ struct btrfs_root *reloc_root;
+ struct extent_buffer *eb;
+ struct btrfs_root_item *root_item;
+ struct btrfs_key root_key;
+ int ret;
+
+ BUG_ON(!root->ref_cows);
+ if (root->reloc_root)
+ return 0;
+
+ root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
+ BUG_ON(!root_item);
+
+ ret = btrfs_copy_root(trans, root, root->commit_root,
+ &eb, BTRFS_TREE_RELOC_OBJECTID);
+ BUG_ON(ret);
+
+ root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
+ root_key.offset = root->root_key.objectid;
+ root_key.type = BTRFS_ROOT_ITEM_KEY;
+
+ memcpy(root_item, &root->root_item, sizeof(root_item));
+ btrfs_set_root_refs(root_item, 0);
+ btrfs_set_root_bytenr(root_item, eb->start);
+ btrfs_set_root_level(root_item, btrfs_header_level(eb));
+ btrfs_set_root_generation(root_item, trans->transid);
+
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+
+ ret = btrfs_insert_root(trans, root->fs_info->tree_root,
+ &root_key, root_item);
+ BUG_ON(ret);
+ kfree(root_item);
+
+ reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
+ &root_key);
+ BUG_ON(!reloc_root);
+ reloc_root->last_trans = trans->transid;
+ reloc_root->commit_root = NULL;
+ reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
+
+ root->reloc_root = reloc_root;
+ return 0;
+}
+
+/*
+ * Core function of space balance.
+ *
+ * The idea is using reloc trees to relocate tree blocks in reference
+ * counted roots. There is one reloc tree for each subvol, and all
+ * reloc trees share same root key objectid. Reloc trees are snapshots
+ * of the latest committed roots of subvols (root->commit_root).
+ *
+ * To relocate a tree block referenced by a subvol, there are two steps.
+ * COW the block through subvol's reloc tree, then update block pointer
+ * in the subvol to point to the new block. Since all reloc trees share
+ * same root key objectid, doing special handing for tree blocks owned
+ * by them is easy. Once a tree block has been COWed in one reloc tree,
+ * we can use the resulting new block directly when the same block is
+ * required to COW again through other reloc trees. By this way, relocated
+ * tree blocks are shared between reloc trees, so they are also shared
+ * between subvols.
+ */
+static noinline int relocate_one_path(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *first_key,
+ struct btrfs_ref_path *ref_path,
+ struct btrfs_block_group_cache *group,
+ struct inode *reloc_inode)
+{
+ struct btrfs_root *reloc_root;
+ struct extent_buffer *eb = NULL;
+ struct btrfs_key *keys;
+ u64 *nodes;
+ int level;
+ int shared_level;
+ int lowest_level = 0;
+ int ret;
+
+ if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
+ lowest_level = ref_path->owner_objectid;
+
+ if (!root->ref_cows) {
+ path->lowest_level = lowest_level;
+ ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
+ BUG_ON(ret < 0);
+ path->lowest_level = 0;
+ btrfs_release_path(root, path);
+ return 0;
+ }
+
+ mutex_lock(&root->fs_info->tree_reloc_mutex);
+ ret = init_reloc_tree(trans, root);
+ BUG_ON(ret);
+ reloc_root = root->reloc_root;
+
+ shared_level = ref_path->shared_level;
+ ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
+
+ keys = ref_path->node_keys;
+ nodes = ref_path->new_nodes;
+ memset(&keys[shared_level + 1], 0,
+ sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
+ memset(&nodes[shared_level + 1], 0,
+ sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
+
+ if (nodes[lowest_level] == 0) {
+ path->lowest_level = lowest_level;
+ ret = btrfs_search_slot(trans, reloc_root, first_key, path,
+ 0, 1);
+ BUG_ON(ret);
+ for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
+ eb = path->nodes[level];
+ if (!eb || eb == reloc_root->node)
+ break;
+ nodes[level] = eb->start;
+ if (level == 0)
+ btrfs_item_key_to_cpu(eb, &keys[level], 0);
+ else
+ btrfs_node_key_to_cpu(eb, &keys[level], 0);
+ }
+ if (nodes[0] &&
+ ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
+ eb = path->nodes[0];
+ ret = replace_extents_in_leaf(trans, reloc_root, eb,
+ group, reloc_inode);
+ BUG_ON(ret);
+ }
+ btrfs_release_path(reloc_root, path);
+ } else {
+ ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
+ lowest_level);
+ BUG_ON(ret);
+ }
+
+ /*
+ * replace tree blocks in the fs tree with tree blocks in
+ * the reloc tree.
+ */
+ ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
+ BUG_ON(ret < 0);
+
+ if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
+ ret = btrfs_search_slot(trans, reloc_root, first_key, path,
+ 0, 0);
+ BUG_ON(ret);
+ extent_buffer_get(path->nodes[0]);
+ eb = path->nodes[0];
+ btrfs_release_path(reloc_root, path);
+ ret = invalidate_extent_cache(reloc_root, eb, group, root);
+ BUG_ON(ret);
+ free_extent_buffer(eb);
+ }
+
+ mutex_unlock(&root->fs_info->tree_reloc_mutex);
+ path->lowest_level = 0;
+ return 0;
+}
+
+static noinline int relocate_tree_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *first_key,
+ struct btrfs_ref_path *ref_path)
+{
+ int ret;
+
+ ret = relocate_one_path(trans, root, path, first_key,
+ ref_path, NULL, NULL);
+ BUG_ON(ret);
+
+ if (root == root->fs_info->extent_root)
+ btrfs_extent_post_op(trans, root);
+
+ return 0;
+}
+
+static noinline int del_extent_zero(struct btrfs_trans_handle *trans,
+ struct btrfs_root *extent_root,
+ struct btrfs_path *path,
+ struct btrfs_key *extent_key)
+{
+ int ret;
+
+ ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
+ if (ret)
+ goto out;
+ ret = btrfs_del_item(trans, extent_root, path);
+out:
+ btrfs_release_path(extent_root, path);
+ return ret;
+}
+
+static noinline struct btrfs_root *read_ref_root(struct btrfs_fs_info *fs_info,
+ struct btrfs_ref_path *ref_path)
+{
+ struct btrfs_key root_key;
+
+ root_key.objectid = ref_path->root_objectid;
+ root_key.type = BTRFS_ROOT_ITEM_KEY;
+ if (is_cowonly_root(ref_path->root_objectid))
+ root_key.offset = 0;
+ else
+ root_key.offset = (u64)-1;
+
+ return btrfs_read_fs_root_no_name(fs_info, &root_key);
+}
+
+static noinline int relocate_one_extent(struct btrfs_root *extent_root,
+ struct btrfs_path *path,
+ struct btrfs_key *extent_key,
+ struct btrfs_block_group_cache *group,
+ struct inode *reloc_inode, int pass)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *found_root;
+ struct btrfs_ref_path *ref_path = NULL;
+ struct disk_extent *new_extents = NULL;
+ int nr_extents = 0;
+ int loops;
+ int ret;
+ int level;
+ struct btrfs_key first_key;
+ u64 prev_block = 0;
+
+
+ trans = btrfs_start_transaction(extent_root, 1);
+ BUG_ON(!trans);
+
+ if (extent_key->objectid == 0) {
+ ret = del_extent_zero(trans, extent_root, path, extent_key);
+ goto out;
+ }
+
+ ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
+ if (!ref_path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ for (loops = 0; ; loops++) {
+ if (loops == 0) {
+ ret = btrfs_first_ref_path(trans, extent_root, ref_path,
+ extent_key->objectid);
+ } else {
+ ret = btrfs_next_ref_path(trans, extent_root, ref_path);
+ }
+ if (ret < 0)
+ goto out;
+ if (ret > 0)
+ break;
+
+ if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
+ ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
+ continue;
+
+ found_root = read_ref_root(extent_root->fs_info, ref_path);
+ BUG_ON(!found_root);
+ /*
+ * for reference counted tree, only process reference paths
+ * rooted at the latest committed root.
+ */
+ if (found_root->ref_cows &&
+ ref_path->root_generation != found_root->root_key.offset)
+ continue;
+
+ if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
+ if (pass == 0) {
+ /*
+ * copy data extents to new locations
+ */
+ u64 group_start = group->key.objectid;
+ ret = relocate_data_extent(reloc_inode,
+ extent_key,
+ group_start);
+ if (ret < 0)
+ goto out;
+ break;
+ }
+ level = 0;
+ } else {
+ level = ref_path->owner_objectid;
+ }
+
+ if (prev_block != ref_path->nodes[level]) {
+ struct extent_buffer *eb;
+ u64 block_start = ref_path->nodes[level];
+ u64 block_size = btrfs_level_size(found_root, level);
+
+ eb = read_tree_block(found_root, block_start,
+ block_size, 0);
+ btrfs_tree_lock(eb);
+ BUG_ON(level != btrfs_header_level(eb));
+
+ if (level == 0)
+ btrfs_item_key_to_cpu(eb, &first_key, 0);
+ else
+ btrfs_node_key_to_cpu(eb, &first_key, 0);
+
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+ prev_block = block_start;
+ }
+
+ btrfs_record_root_in_trans(found_root);
+ if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
+ /*
+ * try to update data extent references while
+ * keeping metadata shared between snapshots.
+ */
+ if (pass == 1) {
+ ret = relocate_one_path(trans, found_root,
+ path, &first_key, ref_path,
+ group, reloc_inode);
+ if (ret < 0)
+ goto out;
+ continue;
+ }
+ /*
+ * use fallback method to process the remaining
+ * references.
+ */
+ if (!new_extents) {
+ u64 group_start = group->key.objectid;
+ new_extents = kmalloc(sizeof(*new_extents),
+ GFP_NOFS);
+ nr_extents = 1;
+ ret = get_new_locations(reloc_inode,
+ extent_key,
+ group_start, 1,
+ &new_extents,
+ &nr_extents);
+ if (ret)
+ goto out;
+ }
+ ret = replace_one_extent(trans, found_root,
+ path, extent_key,
+ &first_key, ref_path,
+ new_extents, nr_extents);
+ } else {
+ ret = relocate_tree_block(trans, found_root, path,
+ &first_key, ref_path);
+ }
+ if (ret < 0)
+ goto out;
+ }
+ ret = 0;
+out:
+ btrfs_end_transaction(trans, extent_root);
+ kfree(new_extents);
+ kfree(ref_path);
+ return ret;
+}
+
+static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
+{
+ u64 num_devices;
+ u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
+ BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
+
+ num_devices = root->fs_info->fs_devices->rw_devices;
+ if (num_devices == 1) {
+ stripped |= BTRFS_BLOCK_GROUP_DUP;
+ stripped = flags & ~stripped;
+
+ /* turn raid0 into single device chunks */
+ if (flags & BTRFS_BLOCK_GROUP_RAID0)
+ return stripped;
+
+ /* turn mirroring into duplication */
+ if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
+ BTRFS_BLOCK_GROUP_RAID10))
+ return stripped | BTRFS_BLOCK_GROUP_DUP;
+ return flags;
+ } else {
+ /* they already had raid on here, just return */
+ if (flags & stripped)
+ return flags;
+
+ stripped |= BTRFS_BLOCK_GROUP_DUP;
+ stripped = flags & ~stripped;
+
+ /* switch duplicated blocks with raid1 */
+ if (flags & BTRFS_BLOCK_GROUP_DUP)
+ return stripped | BTRFS_BLOCK_GROUP_RAID1;
+
+ /* turn single device chunks into raid0 */
+ return stripped | BTRFS_BLOCK_GROUP_RAID0;
+ }
+ return flags;
+}
+
+static int __alloc_chunk_for_shrink(struct btrfs_root *root,
+ struct btrfs_block_group_cache *shrink_block_group,
+ int force)
+{
+ struct btrfs_trans_handle *trans;
+ u64 new_alloc_flags;
+ u64 calc;
+
+ spin_lock(&shrink_block_group->lock);
+ if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
+ spin_unlock(&shrink_block_group->lock);
+
+ trans = btrfs_start_transaction(root, 1);
+ spin_lock(&shrink_block_group->lock);
+
+ new_alloc_flags = update_block_group_flags(root,
+ shrink_block_group->flags);
+ if (new_alloc_flags != shrink_block_group->flags) {
+ calc =
+ btrfs_block_group_used(&shrink_block_group->item);
+ } else {
+ calc = shrink_block_group->key.offset;
+ }
+ spin_unlock(&shrink_block_group->lock);
+
+ do_chunk_alloc(trans, root->fs_info->extent_root,
+ calc + 2 * 1024 * 1024, new_alloc_flags, force);
+
+ btrfs_end_transaction(trans, root);
+ } else
+ spin_unlock(&shrink_block_group->lock);
+ return 0;
+}
+
+static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ u64 objectid, u64 size)
+{
+ struct btrfs_path *path;
+ struct btrfs_inode_item *item;
+ struct extent_buffer *leaf;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = btrfs_insert_empty_inode(trans, root, path, objectid);
+ if (ret)
+ goto out;
+
+ leaf = path->nodes[0];
+ item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
+ memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
+ btrfs_set_inode_generation(leaf, item, 1);
+ btrfs_set_inode_size(leaf, item, size);
+ btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
+ btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
+ btrfs_mark_buffer_dirty(leaf);
+ btrfs_release_path(root, path);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static noinline struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
+ struct btrfs_block_group_cache *group)
+{
+ struct inode *inode = NULL;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root;
+ struct btrfs_key root_key;
+ u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
+ int err = 0;
+
+ root_key.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
+ root_key.type = BTRFS_ROOT_ITEM_KEY;
+ root_key.offset = (u64)-1;
+ root = btrfs_read_fs_root_no_name(fs_info, &root_key);
+ if (IS_ERR(root))
+ return ERR_CAST(root);
+
+ trans = btrfs_start_transaction(root, 1);
+ BUG_ON(!trans);
+
+ err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
+ if (err)
+ goto out;
+
+ err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
+ BUG_ON(err);
+
+ err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
+ group->key.offset, 0, group->key.offset,
+ 0, 0, 0);
+ BUG_ON(err);
+
+ inode = btrfs_iget_locked(root->fs_info->sb, objectid, root);
+ if (inode->i_state & I_NEW) {
+ BTRFS_I(inode)->root = root;
+ BTRFS_I(inode)->location.objectid = objectid;
+ BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
+ BTRFS_I(inode)->location.offset = 0;
+ btrfs_read_locked_inode(inode);
+ unlock_new_inode(inode);
+ BUG_ON(is_bad_inode(inode));
+ } else {
+ BUG_ON(1);
+ }
+ BTRFS_I(inode)->index_cnt = group->key.objectid;
+
+ err = btrfs_orphan_add(trans, inode);
+out:
+ btrfs_end_transaction(trans, root);
+ if (err) {
+ if (inode)
+ iput(inode);
+ inode = ERR_PTR(err);
+ }
+ return inode;
+}
+
+int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
+{
+
+ struct btrfs_ordered_sum *sums;
+ struct btrfs_sector_sum *sector_sum;
+ struct btrfs_ordered_extent *ordered;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct list_head list;
+ size_t offset;
+ int ret;
+ u64 disk_bytenr;
+
+ INIT_LIST_HEAD(&list);
+
+ ordered = btrfs_lookup_ordered_extent(inode, file_pos);
+ BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
+
+ disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
+ ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
+ disk_bytenr + len - 1, &list);
+
+ while (!list_empty(&list)) {
+ sums = list_entry(list.next, struct btrfs_ordered_sum, list);
+ list_del_init(&sums->list);
+
+ sector_sum = sums->sums;
+ sums->bytenr = ordered->start;
+
+ offset = 0;
+ while (offset < sums->len) {
+ sector_sum->bytenr += ordered->start - disk_bytenr;
+ sector_sum++;
+ offset += root->sectorsize;
+ }
+
+ btrfs_add_ordered_sum(inode, ordered, sums);
+ }
+ btrfs_put_ordered_extent(ordered);
+ return 0;
+}
+
+int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_path *path;
+ struct btrfs_fs_info *info = root->fs_info;
+ struct extent_buffer *leaf;
+ struct inode *reloc_inode;
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_key key;
+ u64 skipped;
+ u64 cur_byte;
+ u64 total_found;
+ u32 nritems;
+ int ret;
+ int progress;
+ int pass = 0;
+
+ root = root->fs_info->extent_root;
+
+ block_group = btrfs_lookup_block_group(info, group_start);
+ BUG_ON(!block_group);
+
+ printk(KERN_INFO "btrfs relocating block group %llu flags %llu\n",
+ (unsigned long long)block_group->key.objectid,
+ (unsigned long long)block_group->flags);
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+
+ reloc_inode = create_reloc_inode(info, block_group);
+ BUG_ON(IS_ERR(reloc_inode));
+
+ __alloc_chunk_for_shrink(root, block_group, 1);
+ set_block_group_readonly(block_group);
+
+ btrfs_start_delalloc_inodes(info->tree_root);
+ btrfs_wait_ordered_extents(info->tree_root, 0);
+again:
+ skipped = 0;
+ total_found = 0;
+ progress = 0;
+ key.objectid = block_group->key.objectid;
+ key.offset = 0;
+ key.type = 0;
+ cur_byte = key.objectid;
+
+ trans = btrfs_start_transaction(info->tree_root, 1);
+ btrfs_commit_transaction(trans, info->tree_root);
+
+ mutex_lock(&root->fs_info->cleaner_mutex);
+ btrfs_clean_old_snapshots(info->tree_root);
+ btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
+ mutex_unlock(&root->fs_info->cleaner_mutex);
+
+ while (1) {
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+next:
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto out;
+ if (ret == 1) {
+ ret = 0;
+ break;
+ }
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ if (key.objectid >= block_group->key.objectid +
+ block_group->key.offset)
+ break;
+
+ if (progress && need_resched()) {
+ btrfs_release_path(root, path);
+ cond_resched();
+ progress = 0;
+ continue;
+ }
+ progress = 1;
+
+ if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY ||
+ key.objectid + key.offset <= cur_byte) {
+ path->slots[0]++;
+ goto next;
+ }
+
+ total_found++;
+ cur_byte = key.objectid + key.offset;
+ btrfs_release_path(root, path);
+
+ __alloc_chunk_for_shrink(root, block_group, 0);
+ ret = relocate_one_extent(root, path, &key, block_group,
+ reloc_inode, pass);
+ BUG_ON(ret < 0);
+ if (ret > 0)
+ skipped++;
+
+ key.objectid = cur_byte;
+ key.type = 0;
+ key.offset = 0;
+ }
+
+ btrfs_release_path(root, path);
+
+ if (pass == 0) {
+ btrfs_wait_ordered_range(reloc_inode, 0, (u64)-1);
+ invalidate_mapping_pages(reloc_inode->i_mapping, 0, -1);
+ }
+
+ if (total_found > 0) {
+ printk(KERN_INFO "btrfs found %llu extents in pass %d\n",
+ (unsigned long long)total_found, pass);
+ pass++;
+ if (total_found == skipped && pass > 2) {
+ iput(reloc_inode);
+ reloc_inode = create_reloc_inode(info, block_group);
+ pass = 0;
+ }
+ goto again;
+ }
+
+ /* delete reloc_inode */
+ iput(reloc_inode);
+
+ /* unpin extents in this range */
+ trans = btrfs_start_transaction(info->tree_root, 1);
+ btrfs_commit_transaction(trans, info->tree_root);
+
+ spin_lock(&block_group->lock);
+ WARN_ON(block_group->pinned > 0);
+ WARN_ON(block_group->reserved > 0);
+ WARN_ON(btrfs_block_group_used(&block_group->item) > 0);
+ spin_unlock(&block_group->lock);
+ put_block_group(block_group);
+ ret = 0;
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int find_first_block_group(struct btrfs_root *root,
+ struct btrfs_path *path, struct btrfs_key *key)
+{
+ int ret = 0;
+ struct btrfs_key found_key;
+ struct extent_buffer *leaf;
+ int slot;
+
+ ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ while (1) {
+ slot = path->slots[0];
+ leaf = path->nodes[0];
+ if (slot >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret == 0)
+ continue;
+ if (ret < 0)
+ goto out;
+ break;
+ }
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+ if (found_key.objectid >= key->objectid &&
+ found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
+ ret = 0;
+ goto out;
+ }
+ path->slots[0]++;
+ }
+ ret = -ENOENT;
+out:
+ return ret;
+}
+
+int btrfs_free_block_groups(struct btrfs_fs_info *info)
+{
+ struct btrfs_block_group_cache *block_group;
+ struct rb_node *n;
+
+ spin_lock(&info->block_group_cache_lock);
+ while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
+ block_group = rb_entry(n, struct btrfs_block_group_cache,
+ cache_node);
+ rb_erase(&block_group->cache_node,
+ &info->block_group_cache_tree);
+ spin_unlock(&info->block_group_cache_lock);
+
+ btrfs_remove_free_space_cache(block_group);
+ down_write(&block_group->space_info->groups_sem);
+ list_del(&block_group->list);
+ up_write(&block_group->space_info->groups_sem);
+
+ WARN_ON(atomic_read(&block_group->count) != 1);
+ kfree(block_group);
+
+ spin_lock(&info->block_group_cache_lock);
+ }
+ spin_unlock(&info->block_group_cache_lock);
+ return 0;
+}
+
+int btrfs_read_block_groups(struct btrfs_root *root)
+{
+ struct btrfs_path *path;
+ int ret;
+ struct btrfs_block_group_cache *cache;
+ struct btrfs_fs_info *info = root->fs_info;
+ struct btrfs_space_info *space_info;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct extent_buffer *leaf;
+
+ root = info->extent_root;
+ key.objectid = 0;
+ key.offset = 0;
+ btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ while (1) {
+ ret = find_first_block_group(root, path, &key);
+ if (ret > 0) {
+ ret = 0;
+ goto error;
+ }
+ if (ret != 0)
+ goto error;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ cache = kzalloc(sizeof(*cache), GFP_NOFS);
+ if (!cache) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ atomic_set(&cache->count, 1);
+ spin_lock_init(&cache->lock);
+ mutex_init(&cache->alloc_mutex);
+ mutex_init(&cache->cache_mutex);
+ INIT_LIST_HEAD(&cache->list);
+ read_extent_buffer(leaf, &cache->item,
+ btrfs_item_ptr_offset(leaf, path->slots[0]),
+ sizeof(cache->item));
+ memcpy(&cache->key, &found_key, sizeof(found_key));
+
+ key.objectid = found_key.objectid + found_key.offset;
+ btrfs_release_path(root, path);
+ cache->flags = btrfs_block_group_flags(&cache->item);
+
+ ret = update_space_info(info, cache->flags, found_key.offset,
+ btrfs_block_group_used(&cache->item),
+ &space_info);
+ BUG_ON(ret);
+ cache->space_info = space_info;
+ down_write(&space_info->groups_sem);
+ list_add_tail(&cache->list, &space_info->block_groups);
+ up_write(&space_info->groups_sem);
+
+ ret = btrfs_add_block_group_cache(root->fs_info, cache);
+ BUG_ON(ret);
+
+ set_avail_alloc_bits(root->fs_info, cache->flags);
+ if (btrfs_chunk_readonly(root, cache->key.objectid))
+ set_block_group_readonly(cache);
+ }
+ ret = 0;
+error:
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_make_block_group(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, u64 bytes_used,
+ u64 type, u64 chunk_objectid, u64 chunk_offset,
+ u64 size)
+{
+ int ret;
+ struct btrfs_root *extent_root;
+ struct btrfs_block_group_cache *cache;
+
+ extent_root = root->fs_info->extent_root;
+
+ root->fs_info->last_trans_new_blockgroup = trans->transid;
+
+ cache = kzalloc(sizeof(*cache), GFP_NOFS);
+ if (!cache)
+ return -ENOMEM;
+
+ cache->key.objectid = chunk_offset;
+ cache->key.offset = size;
+ cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+ atomic_set(&cache->count, 1);
+ spin_lock_init(&cache->lock);
+ mutex_init(&cache->alloc_mutex);
+ mutex_init(&cache->cache_mutex);
+ INIT_LIST_HEAD(&cache->list);
+
+ btrfs_set_block_group_used(&cache->item, bytes_used);
+ btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
+ cache->flags = type;
+ btrfs_set_block_group_flags(&cache->item, type);
+
+ ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
+ &cache->space_info);
+ BUG_ON(ret);
+ down_write(&cache->space_info->groups_sem);
+ list_add_tail(&cache->list, &cache->space_info->block_groups);
+ up_write(&cache->space_info->groups_sem);
+
+ ret = btrfs_add_block_group_cache(root->fs_info, cache);
+ BUG_ON(ret);
+
+ ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
+ sizeof(cache->item));
+ BUG_ON(ret);
+
+ finish_current_insert(trans, extent_root, 0);
+ ret = del_pending_extents(trans, extent_root, 0);
+ BUG_ON(ret);
+ set_avail_alloc_bits(extent_root->fs_info, type);
+
+ return 0;
+}
+
+int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, u64 group_start)
+{
+ struct btrfs_path *path;
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_key key;
+ int ret;
+
+ root = root->fs_info->extent_root;
+
+ block_group = btrfs_lookup_block_group(root->fs_info, group_start);
+ BUG_ON(!block_group);
+ BUG_ON(!block_group->ro);
+
+ memcpy(&key, &block_group->key, sizeof(key));
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+
+ btrfs_remove_free_space_cache(block_group);
+ rb_erase(&block_group->cache_node,
+ &root->fs_info->block_group_cache_tree);
+ down_write(&block_group->space_info->groups_sem);
+ list_del(&block_group->list);
+ up_write(&block_group->space_info->groups_sem);
+
+ spin_lock(&block_group->space_info->lock);
+ block_group->space_info->total_bytes -= block_group->key.offset;
+ block_group->space_info->bytes_readonly -= block_group->key.offset;
+ spin_unlock(&block_group->space_info->lock);
+ block_group->space_info->full = 0;
+
+ put_block_group(block_group);
+ put_block_group(block_group);
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0)
+ ret = -EIO;
+ if (ret < 0)
+ goto out;
+
+ ret = btrfs_del_item(trans, root, path);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
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