Btrfs: bail out if block group has different mixed flag

Currently we allow inconsistence about mixed flag
 (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA).

We'd get ENOSPC if block group has mixed flag and btrfs doesn't.
If that happens, we have one space_info with mixed flag and another
space_info only with BTRFS_BLOCK_GROUP_METADATA, and
global_block_rsv.space_info points to the latter one, but all bytes
from block_group contributes to the mixed space_info, thus all the
allocation will fail with ENOSPC.

This adds a check for the above case.

Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
[ updated message ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 6ccddbfbec42fa1e7f4a6531deb7ac7a9bf032c9..dd357b5fd59bd13561207644c33ad3020bbcd9a2 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -10125,6 +10125,11 @@ int btrfs_read_block_groups(struct btrfs_root *root)
        struct extent_buffer *leaf;
        int need_clear = 0;
        u64 cache_gen;
+       u64 feature;
+       int mixed;
+
+       feature = btrfs_super_incompat_flags(info->super_copy);
+       mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
 
        root = info->extent_root;
        key.objectid = 0;
@@ -10178,6 +10183,15 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                                   btrfs_item_ptr_offset(leaf, path->slots[0]),
                                   sizeof(cache->item));
                cache->flags = btrfs_block_group_flags(&cache->item);
+               if (!mixed &&
+                   ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
+                   (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
+                       btrfs_err(info,
+"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
+                                 cache->key.objectid);
+                       ret = -EINVAL;
+                       goto error;
+               }
 
                key.objectid = found_key.objectid + found_key.offset;
                btrfs_release_path(path);