[v4,1/9] btrfs: add raid stripe tree definitions

Commit Message

Johannes Thumshirn Dec. 7, 2022, 2:22 p.m. UTC

Add definitions for the raid stripe tree. This tree will hold information
about the on-disk layout of the stripes in a RAID set.

Each stripe extent has a 1:1 relationship with an on-disk extent item and
is doing the logical to per-drive physical address translation for the
extent item in question.

Signed-off-by: Johannes Thumshirn <[e-mail]>
---
 fs/btrfs/accessors.h            | 29 +++++++++++++++++++++++++++++
 include/uapi/linux/btrfs_tree.h | 20 ++++++++++++++++++--
 2 files changed, 47 insertions(+), 2 deletions(-)

Patch

diff --git a/fs/btrfs/accessors.h b/fs/btrfs/accessors.h
index ceadfc5d6c66..6e753b63faae 100644
--- a/fs/btrfs/accessors.h
+++ b/fs/btrfs/accessors.h
@@ -306,6 +306,35 @@  BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
 BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
 BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec, nsec, 32);
 
+BTRFS_SETGET_FUNCS(raid_stride_devid, struct btrfs_raid_stride, devid, 64);
+BTRFS_SETGET_FUNCS(raid_stride_physical, struct btrfs_raid_stride, physical, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_raid_stride_devid, struct btrfs_raid_stride, devid, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_raid_stride_physical, struct btrfs_raid_stride, physical, 64);
+
+static inline struct btrfs_raid_stride *btrfs_raid_stride_nr(
+					 struct btrfs_stripe_extent *dps, int nr)
+{
+	unsigned long offset = (unsigned long)dps;
+
+	offset += offsetof(struct btrfs_stripe_extent, strides);
+	offset += nr * sizeof(struct btrfs_raid_stride);
+	return (struct btrfs_raid_stride *)offset;
+}
+
+static inline u64 btrfs_raid_stride_devid_nr(const struct extent_buffer *eb,
+					       struct btrfs_stripe_extent *dps,
+					       int nr)
+{
+	return btrfs_raid_stride_devid(eb, btrfs_raid_stride_nr(dps, nr));
+}
+
+static inline u64 btrfs_raid_stride_physical_nr(const struct extent_buffer *eb,
+						  struct btrfs_stripe_extent *dps,
+						  int nr)
+{
+	return btrfs_raid_stride_physical(eb, btrfs_raid_stride_nr(dps, nr));
+}
+
 /* struct btrfs_dev_extent */
 BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent, chunk_tree, 64);
 BTRFS_SETGET_FUNCS(dev_extent_chunk_objectid, struct btrfs_dev_extent,
diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
index ab38d0f411fa..64e6bf2a10d8 100644
--- a/include/uapi/linux/btrfs_tree.h
+++ b/include/uapi/linux/btrfs_tree.h
@@ -4,9 +4,8 @@ 
 
 #include <linux/btrfs.h>
 #include <linux/types.h>
-#ifdef __KERNEL__
 #include <linux/stddef.h>
-#else
+#ifndef __KERNEL__
 #include <stddef.h>
 #endif
 
@@ -73,6 +72,9 @@ 
 /* Holds the block group items for extent tree v2. */
 #define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL
 
+/* tracks RAID stripes in block groups. */
+#define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
+
 /* device stats in the device tree */
 #define BTRFS_DEV_STATS_OBJECTID 0ULL
 
@@ -281,6 +283,8 @@ 
  */
 #define BTRFS_QGROUP_RELATION_KEY       246
 
+#define BTRFS_RAID_STRIPE_KEY		247
+
 /*
  * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY.
  */
@@ -715,6 +719,18 @@  struct btrfs_free_space_header {
 	__le64 num_bitmaps;
 } __attribute__ ((__packed__));
 
+struct btrfs_raid_stride {
+	/* btrfs device-id this raid extent lives on */
+	__le64 devid;
+	/* physical location on disk */
+	__le64 physical;
+};
+
+struct btrfs_stripe_extent {
+	/* array of raid strides this stripe is composed of */
+	__DECLARE_FLEX_ARRAY(struct btrfs_raid_stride, strides);
+};
+
 #define BTRFS_HEADER_FLAG_WRITTEN	(1ULL << 0)
 #define BTRFS_HEADER_FLAG_RELOC		(1ULL << 1)