Btrfs: Make the resizer work based on shrinking and growing devices

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 57 insertions, 88 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c49592c5127a..6540095544e8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -187,6 +187,7 @@ static int noinline find_search_start(struct btrfs_root *root,
 
         if (!cache)
                 goto out;
+
         total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
         free_space_cache = &root->fs_info->free_space_cache;
 
@@ -196,7 +197,7 @@ again:
                 goto out;
 
         last = max(search_start, cache->key.objectid);
-        if (!block_group_bits(cache, data)) {
+        if (!block_group_bits(cache, data) || cache->ro) {
                 goto new_group;
         }
 
@@ -221,6 +222,8 @@ again:
                         continue;
                 }
                 spin_unlock_irq(&free_space_cache->lock);
+                if (cache->ro)
+                        goto new_group;
                 if (start + num > cache->key.objectid + cache->key.offset)
                         goto new_group;
                 if (start + num  > total_fs_bytes)
@@ -319,7 +322,7 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
         if (search_start && search_start < total_fs_bytes) {
                 struct btrfs_block_group_cache *shint;
                 shint = btrfs_lookup_block_group(info, search_start);
-                if (shint && block_group_bits(shint, data)) {
+                if (shint && block_group_bits(shint, data) && !shint->ro) {
                         used = btrfs_block_group_used(&shint->item);
                         if (used + shint->pinned <
                             div_factor(shint->key.offset, factor)) {
@@ -327,7 +330,7 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
                         }
                 }
         }
-        if (hint && block_group_bits(hint, data) &&
+        if (hint && !hint->ro && block_group_bits(hint, data) &&
             hint->key.objectid < total_fs_bytes) {
                 used = btrfs_block_group_used(&hint->item);
                 if (used + hint->pinned <
@@ -364,7 +367,7 @@ again:
                 if (cache->key.objectid > total_fs_bytes)
                         break;
 
-                if (block_group_bits(cache, data)) {
+                if (!cache->ro && block_group_bits(cache, data)) {
                         if (full_search)
                                 free_check = cache->key.offset;
                         else
@@ -1020,6 +1023,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
         if (found) {
                 found->total_bytes += total_bytes;
                 found->bytes_used += bytes_used;
+                found->full = 0;
                 WARN_ON(found->total_bytes < found->bytes_used);
                 *space_info = found;
                 return 0;
@@ -1700,7 +1704,6 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
         u64 super_used;
         u64 root_used;
         u64 search_start = 0;
-        u64 new_hint;
         u64 alloc_profile;
         u32 sizes[2];
         struct btrfs_fs_info *info = root->fs_info;
@@ -1724,7 +1727,7 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
         }
 again:
-        if (root->ref_cows) {
+        if (root != root->fs_info->extent_root) {
                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
                                              2 * 1024 * 1024,
@@ -1738,10 +1741,6 @@ again:
                 BUG_ON(ret);
         }
 
-        new_hint = max(hint_byte, root->fs_info->alloc_start);
-        if (new_hint < btrfs_super_total_bytes(&info->super_copy))
-                hint_byte = new_hint;
-
         WARN_ON(num_bytes < root->sectorsize);
         ret = find_free_extent(trans, root, num_bytes, empty_size,
                                search_start, search_end, hint_byte, ins,
@@ -2473,15 +2472,16 @@ out:
         return ret;
 }
 
-int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
+int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
 {
         struct btrfs_trans_handle *trans;
         struct btrfs_root *tree_root = root->fs_info->tree_root;
         struct btrfs_path *path;
         u64 cur_byte;
         u64 total_found;
+        u64 shrink_last_byte;
+        struct btrfs_block_group_cache *shrink_block_group;
         struct btrfs_fs_info *info = root->fs_info;
-        struct extent_io_tree *block_group_cache;
         struct btrfs_key key;
         struct btrfs_key found_key;
         struct extent_buffer *leaf;
@@ -2489,17 +2489,29 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
         int ret;
         int progress = 0;
 
-        btrfs_set_super_total_bytes(&info->super_copy, new_size);
-        clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
-                           GFP_NOFS);
-        block_group_cache = &info->block_group_cache;
+        shrink_block_group = btrfs_lookup_block_group(root->fs_info,
+                                                      shrink_start);
+        BUG_ON(!shrink_block_group);
+
+        shrink_last_byte = shrink_start + shrink_block_group->key.offset;
+
+        shrink_block_group->space_info->total_bytes -=
+                shrink_block_group->key.offset;
+printk("shrink_extent_tree %Lu -> %Lu type %Lu\n", shrink_start, shrink_last_byte, shrink_block_group->flags);
         path = btrfs_alloc_path();
         root = root->fs_info->extent_root;
         path->reada = 2;
 
 again:
+        trans = btrfs_start_transaction(root, 1);
+        do_chunk_alloc(trans, root->fs_info->extent_root,
+                        btrfs_block_group_used(&shrink_block_group->item) +
+                        2 * 1024 * 1024, shrink_block_group->flags);
+        btrfs_end_transaction(trans, root);
+        shrink_block_group->ro = 1;
+
         total_found = 0;
-        key.objectid = new_size;
+        key.objectid = shrink_start;
         key.offset = 0;
         key.type = 0;
         cur_byte = key.objectid;
@@ -2511,10 +2523,12 @@ again:
         ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
         if (ret < 0)
                 goto out;
+
         if (ret == 0) {
                 leaf = path->nodes[0];
                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
-                if (found_key.objectid + found_key.offset > new_size) {
+                if (found_key.objectid + found_key.offset > shrink_start &&
+                    found_key.objectid < shrink_last_byte) {
                         cur_byte = found_key.objectid;
                         key.objectid = cur_byte;
                 }
@@ -2543,6 +2557,9 @@ next:
 
                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 
+                if (found_key.objectid >= shrink_last_byte)
+                        break;
+
                 if (progress && need_resched()) {
                         memcpy(&key, &found_key, sizeof(key));
                         mutex_unlock(&root->fs_info->fs_mutex);
@@ -2583,68 +2600,31 @@ next:
                 goto again;
         }
 
+        /*
+         * we've freed all the extents, now remove the block
+         * group item from the tree
+         */
         trans = btrfs_start_transaction(root, 1);
-        key.objectid = new_size;
-        key.offset = 0;
-        key.type = 0;
-        while(1) {
-                u64 ptr;
-
-                ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
-                if (ret < 0)
-                        goto out;
-
-                leaf = path->nodes[0];
-                nritems = btrfs_header_nritems(leaf);
-bg_next:
-                if (path->slots[0] >= nritems) {
-                        ret = btrfs_next_leaf(root, path);
-                        if (ret < 0)
-                                break;
-                        if (ret == 1) {
-                                ret = 0;
-                                break;
-                        }
-                        leaf = path->nodes[0];
-                        btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+        memcpy(&key, &shrink_block_group->key, sizeof(key));
 
-                        /*
-                         * btrfs_next_leaf doesn't cow buffers, we have to
-                         * do the search again
-                         */
-                        memcpy(&key, &found_key, sizeof(key));
-                        btrfs_release_path(root, path);
-                        goto resched_check;
-                }
+        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+        if (ret > 0)
+                ret = -EIO;
+        if (ret < 0)
+                goto out;
 
-                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
-                if (btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
-                        printk("shrinker found key %Lu %u %Lu\n",
-                                found_key.objectid, found_key.type,
-                                found_key.offset);
-                        path->slots[0]++;
-                        goto bg_next;
-                }
-                ret = get_state_private(&info->block_group_cache,
-                                        found_key.objectid, &ptr);
-                if (!ret)
-                        kfree((void *)(unsigned long)ptr);
+        leaf = path->nodes[0];
+        nritems = btrfs_header_nritems(leaf);
+        btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+        kfree(shrink_block_group);
 
-                clear_extent_bits(&info->block_group_cache, found_key.objectid,
-                                  found_key.objectid + found_key.offset - 1,
-                                  (unsigned int)-1, GFP_NOFS);
+        clear_extent_bits(&info->block_group_cache, found_key.objectid,
+                          found_key.objectid + found_key.offset - 1,
+                          (unsigned int)-1, GFP_NOFS);
 
-                key.objectid = found_key.objectid + 1;
-                btrfs_del_item(trans, root, path);
-                btrfs_release_path(root, path);
-resched_check:
-                if (need_resched()) {
-                        mutex_unlock(&root->fs_info->fs_mutex);
-                        cond_resched();
-                        mutex_lock(&root->fs_info->fs_mutex);
-                }
-        }
-        clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
+        btrfs_del_item(trans, root, path);
+        clear_extent_dirty(&info->free_space_cache,
+                           shrink_start, shrink_last_byte - 1,
                            GFP_NOFS);
         btrfs_commit_transaction(trans, root);
 out:
@@ -2652,13 +2632,6 @@ out:
         return ret;
 }
 
-int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
-                           struct btrfs_root *root, u64 new_size)
-{
-        btrfs_set_super_total_bytes(&root->fs_info->super_copy, new_size);
-        return 0;
-}
-
 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
                            struct btrfs_key *key)
 {
@@ -2726,7 +2699,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
 
                 leaf = path->nodes[0];
                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
-                cache = kmalloc(sizeof(*cache), GFP_NOFS);
+                cache = kzalloc(sizeof(*cache), GFP_NOFS);
                 if (!cache) {
                         ret = -ENOMEM;
                         break;
@@ -2736,8 +2709,6 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
                                    sizeof(cache->item));
                 memcpy(&cache->key, &found_key, sizeof(found_key));
-                cache->cached = 0;
-                cache->pinned = 0;
 
                 key.objectid = found_key.objectid + found_key.offset;
                 btrfs_release_path(root, path);
@@ -2789,12 +2760,10 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
         extent_root = root->fs_info->extent_root;
         block_group_cache = &root->fs_info->block_group_cache;
 
-        cache = kmalloc(sizeof(*cache), GFP_NOFS);
+        cache = kzalloc(sizeof(*cache), GFP_NOFS);
         BUG_ON(!cache);
         cache->key.objectid = chunk_offset;
         cache->key.offset = size;
-        cache->cached = 0;
-        cache->pinned = 0;
 
         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
         memset(&cache->item, 0, sizeof(cache->item));