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| author | Chung-Chiang Cheng <cccheng@synology.com> | 2022-05-03 23:25:34 +0800 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-05-19 14:10:31 -0700 |
| commit | 0f9d148167c53a7029aba29cdc45072027033b72 (patch) | |
| tree | 67496eb9b879b5090d8761e84274f18ce5f067f5 | |
| parent | 4dcc3f96e7439f9a3a6e47d7fc147aad1338ddc4 (diff) | |
| download | linux-stable-0f9d148167c53a7029aba29cdc45072027033b72.tar.gz linux-stable-0f9d148167c53a7029aba29cdc45072027033b72.tar.bz2 linux-stable-0f9d148167c53a7029aba29cdc45072027033b72.zip | |
fat: ignore ctime updates, and keep ctime identical to mtime in memory
FAT supports creation time but not change time, and there was no
corresponding timestamp for creation time in previous VFS. The original
implementation took the compromise of saving the in-memory change time
into the on-disk creation time field, but this would lead to compatibility
issues with non-linux systems.
To address this issue, this patch changes the behavior of ctime. It will
no longer be loaded and stored from the creation time on disk. Instead of
that, it'll be consistent with the in-memory mtime and share the same
on-disk field. All updates to mtime will also be applied to ctime in
memory, while all updates to ctime will be ignored.
Link: https://lkml.kernel.org/r/20220503152536.2503003-2-cccheng@synology.com
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | fs/fat/inode.c | 11 | ||||
| -rw-r--r-- | fs/fat/misc.c | 9 |
2 files changed, 10 insertions, 10 deletions
diff --git a/fs/fat/inode.c b/fs/fat/inode.c index cb698a827c9a..d0371913f496 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -567,12 +567,11 @@ int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) & ~((loff_t)sbi->cluster_size - 1)) >> 9; fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0); - if (sbi->options.isvfat) { - fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime, - de->cdate, de->ctime_cs); + inode->i_ctime = inode->i_mtime; + if (sbi->options.isvfat) fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0); - } else - fat_truncate_time(inode, &inode->i_mtime, S_ATIME|S_CTIME); + else + inode->i_atime = fat_truncate_atime(sbi, &inode->i_mtime); return 0; } @@ -888,8 +887,6 @@ retry: &raw_entry->date, NULL); if (sbi->options.isvfat) { __le16 atime; - fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime, - &raw_entry->cdate, &raw_entry->ctime_cs); fat_time_unix2fat(sbi, &inode->i_atime, &atime, &raw_entry->adate, NULL); } diff --git a/fs/fat/misc.c b/fs/fat/misc.c index 80c6f8b3dc75..8ebe49e315ab 100644 --- a/fs/fat/misc.c +++ b/fs/fat/misc.c @@ -347,10 +347,13 @@ int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags) if (flags & S_ATIME) inode->i_atime = fat_truncate_atime(sbi, now); - if (flags & S_CTIME) - inode->i_ctime = fat_truncate_crtime(sbi, now); + /* + * ctime and mtime share the same on-disk field, and should be + * identical in memory. all mtime updates will be applied to ctime, + * but ctime updates are ignored. + */ if (flags & S_MTIME) - inode->i_mtime = fat_truncate_mtime(sbi, now); + inode->i_mtime = inode->i_ctime = fat_truncate_mtime(sbi, now); return 0; } |