btrfs: Separate space_info create/update

Currently the struct space_info creation code is intermixed in the
udpate_space_info function. There are well-defined points at which the
we actually want to create brand-new space_info structs (e.g. during
mount of the filesystem as well as sometimes when adding/initialising
new chunks). In such cases update_space_info is called with 0 as the
bytes parameter. All of this makes for spaghetti code.

Fix it by factoring out the creation code in a separate
create_space_info structure. This also allows to simplify the internals.
Also remove BUG_ON from do_alloc_chunk since the callers handle errors.
Furthermore it will make the update_space_info function not fail,
allowing us to remove error handling in callers. This will come in a
follow up patch.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index da8e49e04eb00886593888940c100acb76036e17..4e88df0b3f0a5681caf8f6a745e4b5c592bb9ded 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3925,15 +3925,60 @@ static const char *alloc_name(u64 flags)
        };
 }
 
+static int create_space_info(struct btrfs_fs_info *info, u64 flags,
+                            struct btrfs_space_info **new)
+{
+
+       struct btrfs_space_info *space_info;
+       int i;
+       int ret;
+
+       space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
+       if (!space_info)
+               return -ENOMEM;
+
+       ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
+                                GFP_KERNEL);
+       if (ret) {
+               kfree(space_info);
+               return ret;
+       }
+
+       for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
+               INIT_LIST_HEAD(&space_info->block_groups[i]);
+       init_rwsem(&space_info->groups_sem);
+       spin_lock_init(&space_info->lock);
+       space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
+       space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
+       init_waitqueue_head(&space_info->wait);
+       INIT_LIST_HEAD(&space_info->ro_bgs);
+       INIT_LIST_HEAD(&space_info->tickets);
+       INIT_LIST_HEAD(&space_info->priority_tickets);
+
+       ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
+                                   info->space_info_kobj, "%s",
+                                   alloc_name(space_info->flags));
+       if (ret) {
+               percpu_counter_destroy(&space_info->total_bytes_pinned);
+               kfree(space_info);
+               return ret;
+       }
+
+       *new = space_info;
+       list_add_rcu(&space_info->list, &info->space_info);
+       if (flags & BTRFS_BLOCK_GROUP_DATA)
+               info->data_sinfo = space_info;
+
+       return ret;
+}
+
 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
                             u64 total_bytes, u64 bytes_used,
                             u64 bytes_readonly,
                             struct btrfs_space_info **space_info)
 {
        struct btrfs_space_info *found;
-       int i;
        int factor;
-       int ret;
 
        if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
                     BTRFS_BLOCK_GROUP_RAID10))
@@ -3957,54 +4002,6 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
                *space_info = found;
                return 0;
        }
-       found = kzalloc(sizeof(*found), GFP_NOFS);
-       if (!found)
-               return -ENOMEM;
-
-       ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
-       if (ret) {
-               kfree(found);
-               return ret;
-       }
-
-       for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
-               INIT_LIST_HEAD(&found->block_groups[i]);
-       init_rwsem(&found->groups_sem);
-       spin_lock_init(&found->lock);
-       found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
-       found->total_bytes = total_bytes;
-       found->disk_total = total_bytes * factor;
-       found->bytes_used = bytes_used;
-       found->disk_used = bytes_used * factor;
-       found->bytes_pinned = 0;
-       found->bytes_reserved = 0;
-       found->bytes_readonly = bytes_readonly;
-       found->bytes_may_use = 0;
-       found->full = 0;
-       found->max_extent_size = 0;
-       found->force_alloc = CHUNK_ALLOC_NO_FORCE;
-       found->chunk_alloc = 0;
-       found->flush = 0;
-       init_waitqueue_head(&found->wait);
-       INIT_LIST_HEAD(&found->ro_bgs);
-       INIT_LIST_HEAD(&found->tickets);
-       INIT_LIST_HEAD(&found->priority_tickets);
-
-       ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
-                                   info->space_info_kobj, "%s",
-                                   alloc_name(found->flags));
-       if (ret) {
-               percpu_counter_destroy(&found->total_bytes_pinned);
-               kfree(found);
-               return ret;
-       }
-
-       *space_info = found;
-       list_add_rcu(&found->list, &info->space_info);
-       if (flags & BTRFS_BLOCK_GROUP_DATA)
-               info->data_sinfo = found;
-
-       return ret;
 }
 
 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
@@ -4521,10 +4518,10 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 
        space_info = __find_space_info(fs_info, flags);
        if (!space_info) {
-               ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
-               BUG_ON(ret); /* -ENOMEM */
+               ret = create_space_info(fs_info, flags, &space_info);
+               if (ret)
+                       return ret;
        }
-       BUG_ON(!space_info); /* Logic error */
 
 again:
        spin_lock(&space_info->lock);
@@ -10225,16 +10222,19 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
        }
 #endif
        /*
-        * Call to ensure the corresponding space_info object is created and
-        * assigned to our block group, but don't update its counters just yet.
-        * We want our bg to be added to the rbtree with its ->space_info set.
+        * Ensure the corresponding space_info object is created and
+        * assigned to our block group. We want our bg to be added to the rbtree
+        * with its ->space_info set.
         */
-       ret = update_space_info(fs_info, cache->flags, 0, 0, 0,
-                               &cache->space_info);
-       if (ret) {
-               btrfs_remove_free_space_cache(cache);
-               btrfs_put_block_group(cache);
-               return ret;
+       cache->space_info = __find_space_info(fs_info, cache->flags);
+       if (!cache->space_info) {
+               ret = create_space_info(fs_info, cache->flags,
+                                      &cache->space_info);
+               if (ret) {
+                       btrfs_remove_free_space_cache(cache);
+                       btrfs_put_block_group(cache);
+                       return ret;
+               }
        }
 
        ret = btrfs_add_block_group_cache(fs_info, cache);
@@ -10808,21 +10808,21 @@ int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
                mixed = 1;
 
        flags = BTRFS_BLOCK_GROUP_SYSTEM;
-       ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
+       ret = create_space_info(fs_info, flags, &space_info);
        if (ret)
                goto out;
 
        if (mixed) {
                flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
-               ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
+               ret = create_space_info(fs_info, flags, &space_info);
        } else {
                flags = BTRFS_BLOCK_GROUP_METADATA;
-               ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
+               ret = create_space_info(fs_info, flags, &space_info);
                if (ret)
                        goto out;
 
                flags = BTRFS_BLOCK_GROUP_DATA;
-               ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
+               ret = create_space_info(fs_info, flags, &space_info);
        }
 out:
        return ret;