[PATCH 3/6] bcache: initialize bcache journal for NVDIMM meta device

[Coly Li <colyli@suse.de>]

The nvm-pages allocator may store and index the NVDIMM pages allocated
for bcache journal. This patch adds the initialization to store bcache
journal space on NVDIMM pages if BCH_FEATURE_INCOMPAT_NVDIMM_META bit is
set by bcache-tools.

If BCH_FEATURE_INCOMPAT_NVDIMM_META is set, get_nvdimm_journal_space()
will return the linear address of NVDIMM pages for bcache journal,
- If there is previously allocated space, find it from nvm-pages owner
  list and return to bch_journal_init().
- If there is no previously allocated space, require a new NVDIMM range
  from the nvm-pages allocator, and return it to bch_journal_init().

And in bch_journal_init(), keys in sb.d[] store the corresponding linear
address from NVDIMM into sb.d[i].ptr[0] where 'i' is the bucket index to
iterate all journal buckets.

Later when bcache journaling code stores the journaling jset, the target
NVDIMM linear address stored (and updated) in sb.d[i].ptr[0] can be used
directly in memory copy from DRAM pages into NVDIMM pages.

Signed-off-by: Coly Li <colyli@suse.de>
Cc: Jianpeng Ma <jianpeng.ma@intel.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
---
 drivers/md/bcache/journal.c | 96 +++++++++++++++++++++++++++++++++++++
 drivers/md/bcache/journal.h |  2 +-
 drivers/md/bcache/super.c   |  9 ++--
 3 files changed, 100 insertions(+), 7 deletions(-)

diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index aefbdb7e003b..3a88092ea14c 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -9,6 +9,8 @@
 #include "btree.h"
 #include "debug.h"
 #include "extents.h"
+#include "nvm-pages.h"
+#include "features.h"
 
 #include <trace/events/bcache.h>
 
@@ -982,3 +984,97 @@ int bch_journal_alloc(struct cache_set *c)
 
 	return 0;
 }
+
+static void *find_journal_nvm_base(struct bch_extent *list, struct cache *ca)
+{
+	void *ret = NULL;
+	struct bch_extent *cur, *next;
+
+	next = list;
+	do {
+		cur = next;
+		/* Match journal area's nvdimm address */
+		if (cur->kaddr == (void *)ca->sb.d[0]) {
+			ret = cur->kaddr;
+			break;
+		}
+		next = list_entry(cur->list.next, struct bch_extent, list);
+	} while (next != list);
+
+	return ret;
+}
+
+static void bch_release_nvm_extent_list(struct bch_extent *list)
+{
+	struct bch_extent *ext;
+	struct list_head *cur, *next;
+
+	list_for_each_safe(cur, next, &list->list) {
+		ext = list_entry(cur, struct bch_extent, list);
+		kfree(ext);
+	}
+}
+
+static void *get_nvdimm_journal_space(struct cache *ca)
+{
+	struct bch_extent *allocated_list = NULL;
+	void *ret = NULL;
+
+	allocated_list = bch_get_allocated_pages(ca->sb.set_uuid);
+	if (allocated_list) {
+		ret = find_journal_nvm_base(allocated_list, ca);
+		bch_release_nvm_extent_list(allocated_list);
+	}
+
+	if (!ret) {
+		int order = ilog2(ca->sb.bucket_size * ca->sb.njournal_buckets /
+				  PAGE_SECTORS);
+
+		ret = bch_nvm_alloc_pages(order, ca->sb.set_uuid);
+		memset(ret, 0, (1 << order) * PAGE_SIZE);
+	}
+
+	return ret;
+}
+
+static int __bch_journal_nvdimm_init(struct cache *ca)
+{
+	int i, ret = 0;
+	void *journal_nvm_base = NULL;
+
+	journal_nvm_base = get_nvdimm_journal_space(ca);
+	if (!journal_nvm_base) {
+		pr_err("Failed to get journal space from nvdimm\n");
+		ret = -1;
+		goto out;
+	}
+
+	/* Iniialized and reloaded from on-disk super block already */
+	if (ca->sb.d[0] != 0)
+		goto out;
+
+	for (i = 0; i < ca->sb.keys; i++)
+		ca->sb.d[i] =
+			(u64)(journal_nvm_base + (ca->sb.bucket_size * i));
+
+out:
+	return ret;
+}
+
+int bch_journal_init(struct cache_set *c)
+{
+	int i, ret = 0;
+	struct cache *ca = c->cache;
+
+	ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
+				2, SB_JOURNAL_BUCKETS);
+
+	if (!bch_has_feature_nvdimm_meta(&ca->sb)) {
+		for (i = 0; i < ca->sb.keys; i++)
+			ca->sb.d[i] = ca->sb.first_bucket + i;
+	} else {
+		ret = __bch_journal_nvdimm_init(ca);
+	}
+
+	return ret;
+}
diff --git a/drivers/md/bcache/journal.h b/drivers/md/bcache/journal.h
index f2ea34d5f431..e3a7fa5a8fda 100644
--- a/drivers/md/bcache/journal.h
+++ b/drivers/md/bcache/journal.h
@@ -179,7 +179,7 @@ void bch_journal_mark(struct cache_set *c, struct list_head *list);
 void bch_journal_meta(struct cache_set *c, struct closure *cl);
 int bch_journal_read(struct cache_set *c, struct list_head *list);
 int bch_journal_replay(struct cache_set *c, struct list_head *list);
-
+int bch_journal_init(struct cache_set *c);
 void bch_journal_free(struct cache_set *c);
 int bch_journal_alloc(struct cache_set *c);
 
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 7fffb6ccfb0c..262dae3ef030 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2071,14 +2071,11 @@ static int run_cache_set(struct cache_set *c)
 		if (bch_journal_replay(c, &journal))
 			goto err;
 	} else {
-		unsigned int j;
-
 		pr_notice("invalidating existing data\n");
-		ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
-					2, SB_JOURNAL_BUCKETS);
 
-		for (j = 0; j < ca->sb.keys; j++)
-			ca->sb.d[j] = ca->sb.first_bucket + j;
+		err = "error initializing journal";
+		if (bch_journal_init(c))
+			goto err;
 
 		bch_initial_gc_finish(c);
 
-- 
2.26.2