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From: Johannes Thumshirn <jth@kernel.org>
Date: Mon, 10 Jun 2024 10:40:25 +0200
Subject: [PATCH 1/3] btrfs: rst: remove encoding field from stripe_extent
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Message-Id: <20240610-b4-rst-updates-v1-1-179c1eec08f2@kernel.org>
References: <20240610-b4-rst-updates-v1-0-179c1eec08f2@kernel.org>
In-Reply-To: <20240610-b4-rst-updates-v1-0-179c1eec08f2@kernel.org>
To: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>, 
 David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, 
 Johannes Thumshirn <johannes.thumshirn@wdc.com>

From: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Remove the encoding field from 'struct btrfs_stripe_extent'. It was
originally intended to encode the RAID type as well as if we're a data
or a parity stripe.

But the RAID type can be inferred form the block-group and the data vs.
parity differentiation can be done easier with adding a new key type
for parity stripes in the RAID stripe tree.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/accessors.h            |  3 ---
 fs/btrfs/print-tree.c           |  5 -----
 fs/btrfs/raid-stripe-tree.c     | 13 -------------
 fs/btrfs/raid-stripe-tree.h     |  3 +--
 fs/btrfs/tree-checker.c         | 19 -------------------
 include/uapi/linux/btrfs_tree.h | 14 +-------------
 6 files changed, 2 insertions(+), 55 deletions(-)

diff --git a/fs/btrfs/accessors.h b/fs/btrfs/accessors.h
index 6c3deaa3e878..b2eb9cde2c5d 100644
--- a/fs/btrfs/accessors.h
+++ b/fs/btrfs/accessors.h
@@ -315,11 +315,8 @@ 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(stripe_extent_encoding, struct btrfs_stripe_extent, encoding, 8);
 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_stripe_extent_encoding,
-			 struct btrfs_stripe_extent, encoding, 8);
 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);
 
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index 7e46aa8a0444..9f1e5e11bf71 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -208,11 +208,6 @@ static void print_raid_stripe_key(const struct extent_buffer *eb, u32 item_size,
 				  struct btrfs_stripe_extent *stripe)
 {
 	const int num_stripes = btrfs_num_raid_stripes(item_size);
-	const u8 encoding = btrfs_stripe_extent_encoding(eb, stripe);
-
-	pr_info("\t\t\tencoding: %s\n",
-		(encoding && encoding < BTRFS_NR_RAID_TYPES) ?
-		btrfs_raid_array[encoding].raid_name : "unknown");
 
 	for (int i = 0; i < num_stripes; i++)
 		pr_info("\t\t\tstride %d devid %llu physical %llu\n",
diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
index 6af6b4b9a32e..e6f7a234b8f6 100644
--- a/fs/btrfs/raid-stripe-tree.c
+++ b/fs/btrfs/raid-stripe-tree.c
@@ -80,7 +80,6 @@ static int btrfs_insert_one_raid_extent(struct btrfs_trans_handle *trans,
 	struct btrfs_key stripe_key;
 	struct btrfs_root *stripe_root = fs_info->stripe_root;
 	const int num_stripes = btrfs_bg_type_to_factor(bioc->map_type);
-	u8 encoding = btrfs_bg_flags_to_raid_index(bioc->map_type);
 	struct btrfs_stripe_extent *stripe_extent;
 	const size_t item_size = struct_size(stripe_extent, strides, num_stripes);
 	int ret;
@@ -94,7 +93,6 @@ static int btrfs_insert_one_raid_extent(struct btrfs_trans_handle *trans,
 
 	trace_btrfs_insert_one_raid_extent(fs_info, bioc->logical, bioc->size,
 					   num_stripes);
-	btrfs_set_stack_stripe_extent_encoding(stripe_extent, encoding);
 	for (int i = 0; i < num_stripes; i++) {
 		u64 devid = bioc->stripes[i].dev->devid;
 		u64 physical = bioc->stripes[i].physical;
@@ -159,7 +157,6 @@ int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
 	struct extent_buffer *leaf;
 	const u64 end = logical + *length;
 	int num_stripes;
-	u8 encoding;
 	u64 offset;
 	u64 found_logical;
 	u64 found_length;
@@ -222,16 +219,6 @@ int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
 
 	num_stripes = btrfs_num_raid_stripes(btrfs_item_size(leaf, slot));
 	stripe_extent = btrfs_item_ptr(leaf, slot, struct btrfs_stripe_extent);
-	encoding = btrfs_stripe_extent_encoding(leaf, stripe_extent);
-
-	if (encoding != btrfs_bg_flags_to_raid_index(map_type)) {
-		ret = -EUCLEAN;
-		btrfs_handle_fs_error(fs_info, ret,
-				      "on-disk stripe encoding %d doesn't match RAID index %d",
-				      encoding,
-				      btrfs_bg_flags_to_raid_index(map_type));
-		goto out;
-	}
 
 	for (int i = 0; i < num_stripes; i++) {
 		struct btrfs_raid_stride *stride = &stripe_extent->strides[i];
diff --git a/fs/btrfs/raid-stripe-tree.h b/fs/btrfs/raid-stripe-tree.h
index c9c258f84903..1ac1c21aac2f 100644
--- a/fs/btrfs/raid-stripe-tree.h
+++ b/fs/btrfs/raid-stripe-tree.h
@@ -48,8 +48,7 @@ static inline bool btrfs_need_stripe_tree_update(struct btrfs_fs_info *fs_info,
 
 static inline int btrfs_num_raid_stripes(u32 item_size)
 {
-	return (item_size - offsetof(struct btrfs_stripe_extent, strides)) /
-		sizeof(struct btrfs_raid_stride);
+	return item_size / sizeof(struct btrfs_raid_stride);
 }
 
 #endif
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index a2c3651a3d8f..1e140f6dabc6 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1682,9 +1682,6 @@ static int check_inode_ref(struct extent_buffer *leaf,
 static int check_raid_stripe_extent(const struct extent_buffer *leaf,
 				    const struct btrfs_key *key, int slot)
 {
-	struct btrfs_stripe_extent *stripe_extent =
-		btrfs_item_ptr(leaf, slot, struct btrfs_stripe_extent);
-
 	if (unlikely(!IS_ALIGNED(key->objectid, leaf->fs_info->sectorsize))) {
 		generic_err(leaf, slot,
 "invalid key objectid for raid stripe extent, have %llu expect aligned to %u",
@@ -1698,22 +1695,6 @@ static int check_raid_stripe_extent(const struct extent_buffer *leaf,
 		return -EUCLEAN;
 	}
 
-	switch (btrfs_stripe_extent_encoding(leaf, stripe_extent)) {
-	case BTRFS_STRIPE_RAID0:
-	case BTRFS_STRIPE_RAID1:
-	case BTRFS_STRIPE_DUP:
-	case BTRFS_STRIPE_RAID10:
-	case BTRFS_STRIPE_RAID5:
-	case BTRFS_STRIPE_RAID6:
-	case BTRFS_STRIPE_RAID1C3:
-	case BTRFS_STRIPE_RAID1C4:
-		break;
-	default:
-		generic_err(leaf, slot, "invalid raid stripe encoding %u",
-			    btrfs_stripe_extent_encoding(leaf, stripe_extent));
-		return -EUCLEAN;
-	}
-
 	return 0;
 }
 
diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
index d24e8e121507..cb103c76d398 100644
--- a/include/uapi/linux/btrfs_tree.h
+++ b/include/uapi/linux/btrfs_tree.h
@@ -747,21 +747,9 @@ struct btrfs_raid_stride {
 	__le64 physical;
 } __attribute__ ((__packed__));
 
-/* The stripe_extent::encoding, 1:1 mapping of enum btrfs_raid_types. */
-#define BTRFS_STRIPE_RAID0	1
-#define BTRFS_STRIPE_RAID1	2
-#define BTRFS_STRIPE_DUP	3
-#define BTRFS_STRIPE_RAID10	4
-#define BTRFS_STRIPE_RAID5	5
-#define BTRFS_STRIPE_RAID6	6
-#define BTRFS_STRIPE_RAID1C3	7
-#define BTRFS_STRIPE_RAID1C4	8
-
 struct btrfs_stripe_extent {
-	__u8 encoding;
-	__u8 reserved[7];
 	/* An array of raid strides this stripe is composed of. */
-	struct btrfs_raid_stride strides[];
+	__DECLARE_FLEX_ARRAY(struct btrfs_raid_stride, strides);
 } __attribute__ ((__packed__));
 
 #define BTRFS_HEADER_FLAG_WRITTEN	(1ULL << 0)

-- 
2.43.0