[PATCH v2] erofs: rename ctime to mtime

From: Gao Xiang
Date: Thu Mar 17 2022 - 07:50:08 EST


From: David Anderson <dvander@xxxxxxxxxx>

EROFS images should inherit modification time rather than change time,
since users and host tooling have no easy way to control change time.

To reflect the new timestamp meaning, i_ctime and i_ctime_nsec are
renamed to i_mtime and i_mtime_nsec.

Signed-off-by: David Anderson <dvander@xxxxxxxxxx>
[ Gao Xiang: update document as well. ]
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
---
If no other concerns, I will apply it for 5.18.

Documentation/filesystems/erofs.rst | 2 +-
fs/erofs/erofs_fs.h | 5 +++--
fs/erofs/inode.c | 4 ++--
3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/Documentation/filesystems/erofs.rst b/Documentation/filesystems/erofs.rst
index 7119aa213be7..bef6d3040ce4 100644
--- a/Documentation/filesystems/erofs.rst
+++ b/Documentation/filesystems/erofs.rst
@@ -40,7 +40,7 @@ Here is the main features of EROFS:
Inode metadata size 32 bytes 64 bytes
Max file size 4 GB 16 EB (also limited by max. vol size)
Max uids/gids 65536 4294967296
- File change time no yes (64 + 32-bit timestamp)
+ Per-inode timestamp no yes (64 + 32-bit timestamp)
Max hardlinks 65536 4294967296
Metadata reserved 4 bytes 14 bytes
===================== ============ =====================================
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 3ea62c6fb00a..1238ca104f09 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -12,6 +12,7 @@
#define EROFS_SUPER_OFFSET 1024

#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001
+#define EROFS_FEATURE_COMPAT_MTIME 0x00000002

/*
* Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
@@ -186,8 +187,8 @@ struct erofs_inode_extended {

__le32 i_uid;
__le32 i_gid;
- __le64 i_ctime;
- __le32 i_ctime_nsec;
+ __le64 i_mtime;
+ __le32 i_mtime_nsec;
__le32 i_nlink;
__u8 i_reserved2[16];
};
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index ff62f84f47d3..e8b37ba5e9ad 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -113,8 +113,8 @@ static void *erofs_read_inode(struct erofs_buf *buf,
set_nlink(inode, le32_to_cpu(die->i_nlink));

/* extended inode has its own timestamp */
- inode->i_ctime.tv_sec = le64_to_cpu(die->i_ctime);
- inode->i_ctime.tv_nsec = le32_to_cpu(die->i_ctime_nsec);
+ inode->i_ctime.tv_sec = le64_to_cpu(die->i_mtime);
+ inode->i_ctime.tv_nsec = le32_to_cpu(die->i_mtime_nsec);

inode->i_size = le64_to_cpu(die->i_size);

--
2.24.4