| Message ID | 20220503152536.2503003-2-cccheng@synology.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v6,1/4] fat: split fat_truncate_time() into separate functions | expand |
Chung-Chiang Cheng <cccheng@synology.com> writes: > 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. Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Thanks. > Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com> > --- > fs/fat/inode.c | 11 ++++------- > 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 bf6051bdf1d1..16d5a52116d3 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 @@ static int __fat_write_inode(struct inode *inode, int wait) > &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 63160e47be00..85bb9dc3af2d 100644 > --- a/fs/fat/misc.c > +++ b/fs/fat/misc.c > @@ -341,10 +341,13 @@ 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; > }
diff --git a/fs/fat/inode.c b/fs/fat/inode.c index bf6051bdf1d1..16d5a52116d3 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 @@ static int __fat_write_inode(struct inode *inode, int wait) &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 63160e47be00..85bb9dc3af2d 100644 --- a/fs/fat/misc.c +++ b/fs/fat/misc.c @@ -341,10 +341,13 @@ 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; }
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. Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com> --- fs/fat/inode.c | 11 ++++------- fs/fat/misc.c | 9 ++++++--- 2 files changed, 10 insertions(+), 10 deletions(-)