On Fri, Apr 01, 2016 at 02:35:00PM +0800, Qu Wenruo wrote:
> Core implement for inband de-duplication.
> It reuse the async_cow_start() facility to do the calculate dedupe hash.
> And use dedupe hash to do inband de-duplication at extent level.
>
> The work flow is as below:
> 1) Run delalloc range for an inode
> 2) Calculate hash for the delalloc range at the unit of dedupe_bs
> 3) For hash match(duplicated) case, just increase source extent ref
> and insert file extent.
> For hash mismatch case, go through the normal cow_file_range()
> fallback, and add hash into dedupe_tree.
> Compress for hash miss case is not supported yet.
>
> Current implement restore all dedupe hash in memory rb-tree, with LRU
> behavior to control the limit.
>
> Signed-off-by: Wang Xiaoguang <wangxg.f...@cn.fujitsu.com>
> Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
> ---
> fs/btrfs/extent-tree.c | 18 ++++
> fs/btrfs/inode.c | 235
> ++++++++++++++++++++++++++++++++++++++++++-------
> fs/btrfs/relocation.c | 16 ++++
> 3 files changed, 236 insertions(+), 33 deletions(-)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 53e1297..dabd721 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -37,6 +37,7 @@
> #include "math.h"
> #include "sysfs.h"
> #include "qgroup.h"
> +#include "dedupe.h"
>
> #undef SCRAMBLE_DELAYED_REFS
>
> @@ -2399,6 +2400,8 @@ static int run_one_delayed_ref(struct
> btrfs_trans_handle *trans,
>
> if (btrfs_delayed_ref_is_head(node)) {
> struct btrfs_delayed_ref_head *head;
> + struct btrfs_fs_info *fs_info = root->fs_info;
> +
> /*
> * we've hit the end of the chain and we were supposed
> * to insert this extent into the tree. But, it got
> @@ -2413,6 +2416,15 @@ static int run_one_delayed_ref(struct
> btrfs_trans_handle *trans,
> btrfs_pin_extent(root, node->bytenr,
> node->num_bytes, 1);
> if (head->is_data) {
> + /*
> + * If insert_reserved is given, it means
> + * a new extent is revered, then deleted
> + * in one tran, and inc/dec get merged to 0.
> + *
> + * In this case, we need to remove its dedup
> + * hash.
> + */
> + btrfs_dedupe_del(trans, fs_info, node->bytenr);
> ret = btrfs_del_csums(trans, root,
> node->bytenr,
> node->num_bytes);
> @@ -6713,6 +6725,12 @@ static int __btrfs_free_extent(struct
> btrfs_trans_handle *trans,
> btrfs_release_path(path);
>
> if (is_data) {
> + ret = btrfs_dedupe_del(trans, info, bytenr);
> + if (ret < 0) {
> + btrfs_abort_transaction(trans, extent_root,
> + ret);
I don't see why an error here should lead to a readonly fs.
--Mark
--
Mark Fasheh
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