At 06/02/2016 06:08 AM, Mark Fasheh wrote:
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
Because such deletion error can lead to corruption.
For example, extent A is already in hash pool.
And when freeing extent A, we need to delete its hash, of course.
But if such deletion fails, which means the hash is still in the pool,
even the extent A no longer exists in extent tree.
If we don't abort trans here, next dedupe write may points to the
non-exist extent A, and cause corruption.
Thanks,
Qu
--
Mark Fasheh
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