On Fri, Jan 29, 2016 at 01:03:31PM +0800, Qu Wenruo wrote:
> Before this patch, btrfs-convert only rely on large enough initial
> system/metadata chunk size to ensure no newer system/meta chunk will be
> created.
>
> But that's not safe enough. So add two new members in fs_info,
> avoid_sys/meta_chunk_alloc flags to prevent any newer system or meta
> chunks to be created before init_btrfs_v2().
>
> Signed-off-by: Qu Wenruo <[email protected]>
> Signed-off-by: David Sterba <[email protected]>
> ---
> btrfs-convert.c | 9 +++++++++
> ctree.h | 3 +++
> extent-tree.c | 10 ++++++++++
> 3 files changed, 22 insertions(+)
>
> diff --git a/btrfs-convert.c b/btrfs-convert.c
> index efa3b02..333f413 100644
> --- a/btrfs-convert.c
> +++ b/btrfs-convert.c
> @@ -2322,6 +2322,13 @@ static int init_btrfs_v2(struct btrfs_mkfs_config
> *cfg, struct btrfs_root *root,
> struct btrfs_fs_info *fs_info = root->fs_info;
> int ret;
>
> + /*
> + * Don't alloc any metadata/system chunk, as we don't want
> + * any meta/sys chunk allcated before all data chunks are inserted.
> + * Or we screw up the chunk layout just like the old implement.
> + */
I don't get this, with this patch set, we can allocate data from DATA chunk,
allocate metadata from METADATA chunk, but then we're not allowed to allocate
new chunks?
Thanks,
-liubo
> + fs_info->avoid_sys_chunk_alloc = 1;
> + fs_info->avoid_meta_chunk_alloc = 1;
> trans = btrfs_start_transaction(root, 1);
> BUG_ON(!trans);
> ret = btrfs_fix_block_accounting(trans, root);
> @@ -2359,6 +2366,8 @@ static int init_btrfs_v2(struct btrfs_mkfs_config *cfg,
> struct btrfs_root *root,
> goto err;
>
> ret = btrfs_commit_transaction(trans, root);
> + fs_info->avoid_sys_chunk_alloc = 0;
> + fs_info->avoid_meta_chunk_alloc = 0;
> err:
> return ret;
> }
> diff --git a/ctree.h b/ctree.h
> index 1443746..187bd27 100644
> --- a/ctree.h
> +++ b/ctree.h
> @@ -1030,6 +1030,9 @@ struct btrfs_fs_info {
> unsigned int quota_enabled:1;
> unsigned int suppress_check_block_errors:1;
> unsigned int ignore_fsid_mismatch:1;
> + unsigned int avoid_meta_chunk_alloc:1;
> + unsigned int avoid_sys_chunk_alloc:1;
> +
>
> int (*free_extent_hook)(struct btrfs_trans_handle *trans,
> struct btrfs_root *root,
> diff --git a/extent-tree.c b/extent-tree.c
> index 93b1945..e7c61b1 100644
> --- a/extent-tree.c
> +++ b/extent-tree.c
> @@ -1904,6 +1904,16 @@ static int do_chunk_alloc(struct btrfs_trans_handle
> *trans,
> thresh)
> return 0;
>
> + /*
> + * Avoid allocating given chunk type
> + */
> + if (extent_root->fs_info->avoid_meta_chunk_alloc &&
> + (flags & BTRFS_BLOCK_GROUP_METADATA))
> + return 0;
> + if (extent_root->fs_info->avoid_sys_chunk_alloc &&
> + (flags & BTRFS_BLOCK_GROUP_SYSTEM))
> + return 0;
> +
> ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes,
> space_info->flags);
> if (ret == -ENOSPC) {
> --
> 2.7.0
>
>
>
> --
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