Thread (7 messages) 7 messages, 3 authors, 2021-11-04
STALE1695d

[PATCH 1/3] btrfs-progs: unify sizeof(struct btrfs_super_block) and BTRFS_SUPER_INFO_SIZE

From: Qu Wenruo <hidden>
Date: 2021-10-21 01:40:45
Subsystem: the rest · Maintainer: Linus Torvalds

Just like kernel change, pad struct btrfs_super_block to 4096 bytes.

Signed-off-by: Qu Wenruo <redacted>
---
 kernel-shared/ctree.h   | 7 +++++++
 kernel-shared/disk-io.h | 3 ---
 2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel-shared/ctree.h b/kernel-shared/ctree.h
index 563ea50b3587..6451690ce4fa 100644
--- a/kernel-shared/ctree.h
+++ b/kernel-shared/ctree.h
@@ -406,6 +406,9 @@ struct btrfs_root_backup {
 	u8 unused_8[10];
 } __attribute__ ((__packed__));
 
+#define BTRFS_SUPER_INFO_OFFSET SZ_64K
+#define BTRFS_SUPER_INFO_SIZE 4096
+
 /*
  * the super block basically lists the main trees of the FS
  * it currently lacks any block count etc etc
@@ -456,8 +459,12 @@ struct btrfs_super_block {
 	__le64 reserved[28];
 	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
 	struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
+	/* Padded to 4096 bytes */
+	u8 padding[565];
 } __attribute__ ((__packed__));
 
+static_assert(sizeof(struct btrfs_super_block) == BTRFS_SUPER_INFO_SIZE);
+
 /*
  * Compat flags that we support.  If any incompat flags are set other than the
  * ones specified below then we will fail to mount
diff --git a/kernel-shared/disk-io.h b/kernel-shared/disk-io.h
index e113d842c906..823e5af37e75 100644
--- a/kernel-shared/disk-io.h
+++ b/kernel-shared/disk-io.h
@@ -23,9 +23,6 @@
 #include "kernel-shared/ctree.h"
 #include "kernel-lib/sizes.h"
 
-#define BTRFS_SUPER_INFO_OFFSET SZ_64K
-#define BTRFS_SUPER_INFO_SIZE 4096
-
 #define BTRFS_SUPER_MIRROR_MAX	 3
 #define BTRFS_SUPER_MIRROR_SHIFT 12
 
-- 
2.33.0
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