On 12/21/2017 02:51 PM, Qu Wenruo wrote:
On 2017年12月20日 16:37, Qu Wenruo wrote:
On 2017年12月20日 16:21, Su Yue wrote:
On 12/20/2017 01:41 PM, Qu Wenruo wrote:
On 2017年12月20日 12:57, Su Yue wrote:
Introduce create_chunk_and_block_block_group() to allocate new chunk
and corresponding block group.
The new function force_cow_in_new_chunk() first allocates new chunk
and records its start.
Then it modifies all metadata block groups cached and full.
Finally it marks the new block group uncached and unfree.
In the next CoW, extents states will be updated automatically by
cache_block_group().
Suggested-by: Qu Wenruo <w...@suse.com>
Signed-off-by: Su Yue <suy.f...@cn.fujitsu.com>
---
cmds-check.c | 80
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 80 insertions(+)
diff --git a/cmds-check.c b/cmds-check.c
index d98d4bda7357..311c8a9f45e8 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -10911,6 +10911,86 @@ out:
return ret;
}
+static int create_chunk_and_block_group(struct btrfs_fs_info
*fs_info,
+ u64 flags, u64 *start, u64 *nbytes)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root = fs_info->extent_root;
+ int ret;
+
+ if ((flags & BTRFS_BLOCK_GROUP_TYPE_MASK) == 0)
+ return -EINVAL;
+
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ error("error starting transaction %s", strerror(-ret));
+ return ret;
+ }
+ ret = btrfs_alloc_chunk(trans, fs_info, start, nbytes, flags);
+ if (ret) {
+ error("fail to allocate new chunk %s", strerror(-ret));
+ goto out;
+ }
+ ret = btrfs_make_block_group(trans, fs_info, 0, flags,
+ BTRFS_FIRST_CHUNK_TREE_OBJECTID, *start, *nbytes);
+ if (ret) {
+ error("fail to make block group for chunk %llu %llu %s",
+ *start, *nbytes, strerror(-ret));
+ goto out;
+ }
+out:
+ btrfs_commit_transaction(trans, root);
+ return ret;
+}
+
+static int force_cow_in_new_chunk(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_block_group_cache *bg;
+ u64 start;
+ u64 nbytes;
+ u64 alloc_profile;
+ u64 flags;
+ int ret;
+
+ alloc_profile = (fs_info->avail_metadata_alloc_bits &
+ fs_info->metadata_alloc_profile);
+ flags = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
+ if (btrfs_fs_incompat(fs_info, MIXED_GROUPS))
+ flags |= BTRFS_BLOCK_GROUP_DATA;
+
+ ret = create_chunk_and_block_group(fs_info, flags, &start,
&nbytes);
Why bother allocating a new chunk by yourself?
Just mark all block groups full and that's all.
Any later tree block allocation like btrfs_search_slot() with @cow = 1
will trigger chunk allocation automatically.
Tried to let it happen but BUG_ON with -ENOSPC.
Then fix it.
It's not a normal behavior in this case.
Thanks,
Qu
And I think the fix to allow btrfs_reserve_extent() to allocate new
chunk will solve a lot of strange BUG_ON().
it just occurred to me that, a lot of use cases relies on the assumption
that btrfs_reserve_extent() will try to allocate new chunks.
Yes, it has many dependency so I considered to do chunk allocation
manually in the patchset. If fix is not good enough, many funtions
of btrfs-progs will behave abnormal.
Since you ask it, I will go to fix it.
Thanks,
Su
Especially for case like convert, certain btrfs check --repair, some
rescue tools.
So this would be a quite nice start point for such fix.
Thanks,
Qu
Do you mean do_chunk_alloc() in btrfs_reserve_extent() which is called
while doing CoW?> In progs, allocation of new chunk during CoW depends
@root->ref_cows.
However, @root->ref_cows should be set only if @root is root of a fs
trees.
Thanks,
Su
Thanks,
Qu
+ if (!ret)
+ printf("Create new chunk %llu %llu\n", start, nbytes);
+ else
+ goto err;
+
+ flags = BTRFS_BLOCK_GROUP_METADATA;
+ /* Mark all metadata block groups cached and full in free space*/
+ ret = modify_block_groups_cache(fs_info, flags, 1);
+ if (ret)
+ goto clear_bg_cache;
+
+ bg = btrfs_lookup_block_group(fs_info, start);
+ if (!bg) {
+ ret = -ENOENT;
+ error("fail to look up block group %llu %llu", start, nbytes);
+ goto clear_bg_cache;
+ }
+
+ /* Clear block group cache just allocated */
+ ret = modify_block_group_cache(fs_info, bg, 0);
+ if (ret)
+ goto clear_bg_cache;
+
+ return 0;
+
+clear_bg_cache:
+ modify_block_groups_cache(fs_info, flags, 0);
+err:
+ return ret;
+}
+
static int check_extent_refs(struct btrfs_root *root,
struct cache_tree *extent_cache)
{
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