search for: check_system_chunk

...+ num_dev = root->fs_info->fs_devices->rw_devices; + else if (type & BTRFS_BLOCK_GROUP_RAID1) + num_dev = 2; + else + num_dev = 1; /* DUP or single */ + + /* metadata for updating devices and chunk tree */ + return btrfs_calc_trans_metadata_size(root, num_dev + 1); +} + +static void check_system_chunk(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 type) +{ + struct btrfs_space_info *info; + u64 left; + u64 thresh; + + info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM); + spin_lock(&info->lock); + left = info->total_bytes - info->bytes_use...

An user reported that he has hit an annoying deadlock while playing with ceph based on btrfs. Current updating device tree requires space from METADATA chunk, so we -may- need to do a recursive chunk allocation when adding/updating dev extent, that is where the deadlock comes from. If we use SYSTEM metadata to update device tree, we can avoid the recursive stuff. Reported-by: Jim Schutt