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Subject[PATCH v3 3/7] erofs: use a better form for complicated on-disk fields
Date
As Joe Perches [1] suggested, let's use a better
form to describe complicated on-disk fields.

p.s. it has different tab alignment looking between
the real file and patch file.
p.p.s. due to changing a different form, some lines
have to exceed 80 characters.
[1] https://lore.kernel.org/r/67d6efbbc9ac6db23215660cb970b7ef29dc0c1d.camel@perches.com/
Reported-by: Joe Perches <joe@perches.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
no change.

fs/erofs/erofs_fs.h | 100 ++++++++++++++++++++++----------------------
1 file changed, 50 insertions(+), 50 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 0782ba9da623..fbdaf873d736 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -17,27 +17,27 @@
#define EROFS_REQUIREMENT_LZ4_0PADDING 0x00000001
#define EROFS_ALL_REQUIREMENTS EROFS_REQUIREMENT_LZ4_0PADDING

-struct erofs_super_block {
-/* 0 */__le32 magic; /* in the little endian */
-/* 4 */__le32 checksum; /* crc32c(super_block) */
-/* 8 */__le32 features; /* (aka. feature_compat) */
-/* 12 */__u8 blkszbits; /* support block_size == PAGE_SIZE only */
-/* 13 */__u8 reserved;
-
-/* 14 */__le16 root_nid;
-/* 16 */__le64 inos; /* total valid ino # (== f_files - f_favail) */
-
-/* 24 */__le64 build_time; /* inode v1 time derivation */
-/* 32 */__le32 build_time_nsec;
-/* 36 */__le32 blocks; /* used for statfs */
-/* 40 */__le32 meta_blkaddr;
-/* 44 */__le32 xattr_blkaddr;
-/* 48 */__u8 uuid[16]; /* 128-bit uuid for volume */
-/* 64 */__u8 volume_name[16]; /* volume name */
-/* 80 */__le32 requirements; /* (aka. feature_incompat) */
-
-/* 84 */__u8 reserved2[44];
-} __packed; /* 128 bytes */
+struct erofs_super_block { /* off description */
+ __le32 magic; /* 0 file system magic number */
+ __le32 checksum; /* 4 crc32c(super_block) */
+ __le32 features; /* 8 (aka. feature_compat) */
+ __u8 blkszbits; /* 12 support PAGE_SIZE only currently */
+ __u8 reserved; /* 13 */
+
+ __le16 root_nid; /* 14 nid of root directory */
+ __le64 inos; /* 16 total valid ino # (== f_files - f_favail) */
+
+ __le64 build_time; /* 24 inode v1 time derivation */
+ __le32 build_time_nsec; /* 32 inode v1 time derivation in nano scale */
+ __le32 blocks; /* 36 used for statfs */
+ __le32 meta_blkaddr; /* 40 start block address of metadata area */
+ __le32 xattr_blkaddr; /* 44 start block address of shared xattr area */
+ __u8 uuid[16]; /* 48 128-bit uuid for volume */
+ __u8 volume_name[16]; /* 64 volume name */
+ __le32 requirements; /* 80 (aka. feature_incompat) */
+
+ __u8 reserved2[44]; /* 84 */
+} __packed; /* 128 bytes */

/*
* erofs inode data mapping:
@@ -73,16 +73,16 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
#define EROFS_I_VERSION_BIT 0
#define EROFS_I_DATA_MAPPING_BIT 1

-struct erofs_inode_v1 {
-/* 0 */__le16 i_advise;
+struct erofs_inode_v1 { /* off description */
+ __le16 i_advise; /* 0 file hints */

/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
-/* 2 */__le16 i_xattr_icount;
-/* 4 */__le16 i_mode;
-/* 6 */__le16 i_nlink;
-/* 8 */__le32 i_size;
-/* 12 */__le32 i_reserved;
-/* 16 */union {
+ __le16 i_xattr_icount; /* 2 encoding for xattr ibody size */
+ __le16 i_mode; /* 4 */
+ __le16 i_nlink; /* 6 */
+ __le32 i_size; /* 8 */
+ __le32 i_reserved; /* 12 */
+ union { /* 16 */
/* file total compressed blocks for data mapping 1 */
__le32 compressed_blocks;
__le32 raw_blkaddr;
@@ -90,26 +90,26 @@ struct erofs_inode_v1 {
/* for device files, used to indicate old/new device # */
__le32 rdev;
} i_u __packed;
-/* 20 */__le32 i_ino; /* only used for 32-bit stat compatibility */
-/* 24 */__le16 i_uid;
-/* 26 */__le16 i_gid;
-/* 28 */__le32 i_reserved2;
-} __packed;
+ __le32 i_ino; /* 20 only used for 32-bit stat compatibility */
+ __le16 i_uid; /* 24 */
+ __le16 i_gid; /* 26 */
+ __le32 i_reserved2; /* 28 */
+} __packed; /* 32 bytes */

/* 32 bytes on-disk inode */
#define EROFS_INODE_LAYOUT_V1 0
/* 64 bytes on-disk inode */
#define EROFS_INODE_LAYOUT_V2 1

-struct erofs_inode_v2 {
-/* 0 */__le16 i_advise;
+struct erofs_inode_v2 { /* off description */
+ __le16 i_advise; /* 0 file hints */

/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
-/* 2 */__le16 i_xattr_icount;
-/* 4 */__le16 i_mode;
-/* 6 */__le16 i_reserved;
-/* 8 */__le64 i_size;
-/* 16 */union {
+ __le16 i_xattr_icount; /* 2 encoding for xattr ibody size */
+ __le16 i_mode; /* 4 */
+ __le16 i_reserved; /* 6 */
+ __le64 i_size; /* 8 */
+ union { /* 16 */
/* file total compressed blocks for data mapping 1 */
__le32 compressed_blocks;
__le32 raw_blkaddr;
@@ -119,15 +119,15 @@ struct erofs_inode_v2 {
} i_u __packed;

/* only used for 32-bit stat compatibility */
-/* 20 */__le32 i_ino;
-
-/* 24 */__le32 i_uid;
-/* 28 */__le32 i_gid;
-/* 32 */__le64 i_ctime;
-/* 40 */__le32 i_ctime_nsec;
-/* 44 */__le32 i_nlink;
-/* 48 */__u8 i_reserved2[16];
-} __packed; /* 64 bytes */
+ __le32 i_ino; /* 20 only used for 32-bit stat compatibility */
+
+ __le32 i_uid; /* 24 */
+ __le32 i_gid; /* 28 */
+ __le64 i_ctime; /* 32 */
+ __le32 i_ctime_nsec; /* 40 */
+ __le32 i_nlink; /* 44 */
+ __u8 i_reserved2[16]; /* 48 */
+} __packed; /* 64 bytes */

#define EROFS_MAX_SHARED_XATTRS (128)
/* h_shared_count between 129 ... 255 are special # */
--
2.17.1
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