[V2,3/3] mdadm: add support for new lockless bitmap

Commit Message

Yu Kuai Nov. 7, 2024, 12:58 p.m. UTC

From: Yu Kuai <[e-mail]>

A new major number 6 is used for the new bitmap.

Noted that for the kernel that doesn't support lockless bitmap, create
such array will fail:

md0: invalid bitmap file superblock: unrecognized superblock version.

Signed-off-by: Yu Kuai <[e-mail]>
---
 Create.c | 5 ++++-
 Grow.c   | 3 ++-
 bitmap.h | 1 +
 mdadm.c  | 9 ++++++++-
 mdadm.h  | 1 +
 5 files changed, 16 insertions(+), 3 deletions(-)

Patch

diff --git a/Create.c b/Create.c
index ade677cd..ad9e31a3 100644
--- a/Create.c
+++ b/Create.c
@@ -541,6 +541,8 @@  int Create(struct supertype *st, struct mddev_ident *ident, int subdevs,
 			pr_err("At least 2 nodes are needed for cluster-md\n");
 			return 1;
 		}
+	} else if (s->btype == BitmapLockless) {
+		major_num = BITMAP_MAJOR_LOCKLESS;
 	}
 
 	memset(&info, 0, sizeof(info));
@@ -1195,7 +1197,8 @@  int Create(struct supertype *st, struct mddev_ident *ident, int subdevs,
 	 * to stop another mdadm from finding and using those devices.
 	 */
 
-	if (s->btype == BitmapInternal || s->btype == BitmapCluster) {
+	if (s->btype == BitmapInternal || s->btype == BitmapCluster ||
+	    s->btype == BitmapLockless) {
 		if (!st->ss->add_internal_bitmap) {
 			pr_err("internal bitmaps not supported with %s metadata\n",
 				st->ss->name);
diff --git a/Grow.c b/Grow.c
index cc1be6cc..3905f64c 100644
--- a/Grow.c
+++ b/Grow.c
@@ -383,7 +383,8 @@  int Grow_addbitmap(char *devname, int fd, struct context *c, struct shape *s)
 		free(mdi);
 	}
 
-	if (s->btype == BitmapInternal || s->btype == BitmapCluster) {
+	if (s->btype == BitmapInternal || s->btype == BitmapCluster ||
+	    s->btype == BitmapLockless) {
 		int rv;
 		int d;
 		int offset_setable = 0;
diff --git a/bitmap.h b/bitmap.h
index 7b1f80f2..4b5d2d93 100644
--- a/bitmap.h
+++ b/bitmap.h
@@ -13,6 +13,7 @@ 
 #define BITMAP_MAJOR_HI 4
 #define	BITMAP_MAJOR_HOSTENDIAN 3
 #define	BITMAP_MAJOR_CLUSTERED 5
+#define	BITMAP_MAJOR_LOCKLESS 6
 
 #define BITMAP_MINOR 39
 
diff --git a/mdadm.c b/mdadm.c
index 605ccec9..eaffe84d 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -56,6 +56,12 @@  static mdadm_status_t set_bitmap_value(struct shape *s, struct context *c, char
 		return MDADM_STATUS_SUCCESS;
 	}
 
+	if (strcmp(val, "lockless") == 0) {
+		s->btype = BitmapLockless;
+		pr_info("Experimental lockless bitmap, use at your own disk!\n");
+		return MDADM_STATUS_SUCCESS;
+	}
+
 	if (strcmp(val, "clustered") == 0) {
 		s->btype = BitmapCluster;
 		/* Set the default number of cluster nodes
@@ -1251,7 +1257,8 @@  int main(int argc, char *argv[])
 			pr_err("--bitmap is required for consistency policy: %s\n",
 			       map_num_s(consistency_policies, s.consistency_policy));
 			exit(2);
-		} else if ((s.btype == BitmapInternal || s.btype == BitmapCluster) &&
+		} else if ((s.btype == BitmapInternal || s.btype == BitmapCluster ||
+			    s.btype == BitmapLockless) &&
 			   s.consistency_policy != CONSISTENCY_POLICY_BITMAP &&
 			   s.consistency_policy != CONSISTENCY_POLICY_JOURNAL) {
 			pr_err("--bitmap is not compatible with consistency policy: %s\n",
diff --git a/mdadm.h b/mdadm.h
index af54a6ab..5e35d78c 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -607,6 +607,7 @@  enum bitmap_type {
 	BitmapNone,
 	BitmapInternal,
 	BitmapCluster,
+	BitmapLockless,
 	BitmapUnknown,
 };