* Re: [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps
@ 2007-03-26 4:05 Hiroyuki Machida
2007-03-26 15:31 ` OGAWA Hirofumi
0 siblings, 1 reply; 6+ messages in thread
From: Hiroyuki Machida @ 2007-03-26 4:05 UTC (permalink / raw)
To: OGAWA Hirofumi, Paul Collins; +Cc: linux-kernel
HI OGAWA-san and Paul-san,
Sorry late response,
I'm not famillar with recent fat code, but code itself looks good for
just turn on/off time adjusting. On the other hand, I feel we need more
consideration on use cases/requirements. I feel that turning off
time adjustment is a just ad-hoc solution to issues like Paul san
brought up.
Thanks,
Hiroyuki
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote on 2007/03/19 23:31:06:
> Paul Collins <paul@briny.ondioline.org> writes:
>
> > Hello,
>
> Hello,
>
> > Here is a patch that adds a mount option named "posixtime" that, when
> > enabled, causes the fat/vfat code to not adjust timestamps as they are
> > read/written to/from disk. The intent of the adjustment as performed
> > by the existing code appears to be to present correct timestamps to
> > Windows and friends, which treat the timestamp values as local time.
> >
> > However, the systems that I use to update my FAT32 filesystems are all
> > running Linux, and as such will process POSIX timestamps correctly.
> > (The filesystems are on disks in digital audio players, which do not
> > process timestamps except to check if they have changed.) Due to the
> > aforementioned adjustment on read/write, after a Daylight Savings
> > transition I must update the file timestamps on the filesystems so
> > that rsync does not needlessly re-copy files.
> >
> > Please review and consider applying this patch.
>
> Thanks. Looks good to me as start. IIRC, Machida-san did this few
> years ago. Machida-san, do you have any comment?
>
> > diff --git a/fs/fat/dir.c b/fs/fat/dir.c
> > index c16af24..d6c0a7f 100644
> > --- a/fs/fat/dir.c
> > +++ b/fs/fat/dir.c
> > @@ -1064,7 +1064,7 @@ int fat_alloc_new_dir(struct inode *dir, struct
> timespec *ts)
> > goto error_free;
> > }
> >
> > - fat_date_unix2dos(ts->tv_sec, &time, &date);
> > + fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.adjust);
> >
> > de = (struct msdos_dir_entry *)bhs[0]->b_data;
> > /* filling the new directory slots ("." and ".." entries) */
> > diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> > index a9e4688..02d9225 100644
> > --- a/fs/fat/inode.c
> > +++ b/fs/fat/inode.c
> > @@ -374,17 +374,20 @@ static int fat_fill_inode(struct inode *inode,
> struct msdos_dir_entry *de)
> > inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
> > & ~((loff_t)sbi->cluster_size - 1)) >> 9;
> > inode->i_mtime.tv_sec =
> > - date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date));
> > + date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date),
> > + sbi->options.adjust);
> > inode->i_mtime.tv_nsec = 0;
> > if (sbi->options.isvfat) {
> > int secs = de->ctime_cs / 100;
> > int csecs = de->ctime_cs % 100;
> > inode->i_ctime.tv_sec =
> > date_dos2unix(le16_to_cpu(de->ctime),
> > - le16_to_cpu(de->cdate)) + secs;
> > + le16_to_cpu(de->cdate),
> > + sbi->options.adjust) + secs;
> > inode->i_ctime.tv_nsec = csecs * 10000000;
> > inode->i_atime.tv_sec =
> > - date_dos2unix(0, le16_to_cpu(de->adate));
> > + date_dos2unix(0, le16_to_cpu(de->adate),
> > + sbi->options.adjust);
> > inode->i_atime.tv_nsec = 0;
> > } else
> > inode->i_ctime = inode->i_atime = inode->i_mtime;
> > @@ -592,11 +595,14 @@ retry:
> > raw_entry->attr = fat_attr(inode);
> > raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
> > raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
> > - fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time,
> &raw_entry->date);
> > + fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time,
> &raw_entry->date,
> > + sbi->options.adjust);
> > if (sbi->options.isvfat) {
> > __le16 atime;
> > -
> fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cd
> ate);
> > - fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
> > +
> fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cd
> ate,
> > + sbi->options.adjust);
> > + fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate,
> > + sbi->options.adjust);
> > raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
> > inode->i_ctime.tv_nsec / 10000000;
> > }
> > @@ -854,7 +860,7 @@ enum {
> > Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
> > Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
> > Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
> > - Opt_obsolate, Opt_flush, Opt_err,
> > + Opt_obsolate, Opt_flush, Opt_posixtime, Opt_err,
> > };
> >
> > static match_table_t fat_tokens = {
> > @@ -887,6 +893,7 @@ static match_table_t fat_tokens = {
> > {Opt_obsolate, "cvf_options=%100s"},
> > {Opt_obsolate, "posix"},
> > {Opt_flush, "flush"},
> > + {Opt_posixtime, "posixtime"},
> > {Opt_err, NULL},
> > };
> > static match_table_t msdos_tokens = {
> > @@ -950,6 +957,7 @@ static int parse_options(char *options, int
> is_vfat, int silent, int *debug,
> > opts->utf8 = opts->unicode_xlate = 0;
> > opts->numtail = 1;
> > opts->nocase = 0;
> > + opts->adjust = 1;
> > *debug = 0;
> >
> > if (!options)
> > @@ -1032,6 +1040,10 @@ static int parse_options(char *options, int
> is_vfat, int silent, int *debug,
> > opts->flush = 1;
> > break;
> >
> > + case Opt_posixtime:
> > + opts->adjust = 0;
> > + break;
> > +
> > /* msdos specific */
> > case Opt_dots:
> > opts->dotsOK = 1;
> > diff --git a/fs/fat/misc.c b/fs/fat/misc.c
> > index 308f2b6..72a1a29 100644
> > --- a/fs/fat/misc.c
> > +++ b/fs/fat/misc.c
> > @@ -143,7 +143,7 @@ static int day_n[] = {
> > };
> >
> > /* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1
> 70). */
> > -int date_dos2unix(unsigned short time, unsigned short date)
> > +int date_dos2unix(unsigned short time, unsigned short date, int
> adjust)
> > {
> > int month, year, secs;
> >
> > @@ -157,16 +157,18 @@ int date_dos2unix(unsigned short time, unsigned
> short date)
> > ((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0
> &&
> > month < 2 ? 1 : 0)+3653);
> > /* days since 1.1.70 plus 80's leap day */
> > - secs += sys_tz.tz_minuteswest*60;
> > + if (adjust)
> > + secs += sys_tz.tz_minuteswest*60;
> > return secs;
> > }
> >
> > /* Convert linear UNIX date to a MS-DOS time/date pair. */
> > -void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date)
> > +void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date,
> int adjust)
> > {
> > int day, year, nl_day, month;
> >
> > - unix_date -= sys_tz.tz_minuteswest*60;
> > + if (adjust)
> > + unix_date -= sys_tz.tz_minuteswest*60;
> >
> > /* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
> > if (unix_date < 315532800)
> > diff --git a/fs/vfat/namei.c b/fs/vfat/namei.c
> > index 0afd745..7e5487b 100644
> > --- a/fs/vfat/namei.c
> > +++ b/fs/vfat/namei.c
> > @@ -626,7 +626,7 @@ shortname:
> > memcpy(de->name, msdos_name, MSDOS_NAME);
> > de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
> > de->lcase = lcase;
> > - fat_date_unix2dos(ts->tv_sec, &time, &date);
> > + fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.adjust);
> > de->time = de->ctime = time;
> > de->date = de->cdate = de->adate = date;
> > de->ctime_cs = 0;
> > diff --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h
> > index 24a9ef1..b3eeec8 100644
> > --- a/include/linux/msdos_fs.h
> > +++ b/include/linux/msdos_fs.h
> > @@ -205,7 +205,8 @@ struct fat_mount_options {
> > numtail:1, /* Does first alias have a numeric '~1' type
> tail? */
> > atari:1, /* Use Atari GEMDOS variation of MS-DOS fs */
> > flush:1, /* write things quickly */
> > - nocase:1; /* Does this need case conversion? 0=need case
> conversion*/
> > + nocase:1, /* Does this need case conversion? 0=need case
> conversion*/
> > + adjust:1; /* Adjust time and date based on sys_tz?*/
> > };
> >
> > #define FAT_HASH_BITS 8
> > @@ -421,8 +422,8 @@ extern int fat_flush_inodes(struct super_block
> *sb, struct inode *i1,
> > extern void fat_fs_panic(struct super_block *s, const char *fmt,
> ...);
> > extern void fat_clusters_flush(struct super_block *sb);
> > extern int fat_chain_add(struct inode *inode, int new_dclus, int
> nr_cluster);
> > -extern int date_dos2unix(unsigned short time, unsigned short date);
> > -extern void fat_date_unix2dos(int unix_date, __le16 *time, __le16
> *date);
> > +extern int date_dos2unix(unsigned short time, unsigned short date,
> int adjust);
> > +extern void fat_date_unix2dos(int unix_date, __le16 *time, __le16
> *date, int adjust);
> > extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
> >
> > int fat_cache_init(void);
> --
> OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps
2007-03-26 4:05 [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps Hiroyuki Machida
@ 2007-03-26 15:31 ` OGAWA Hirofumi
2007-03-27 9:52 ` Paul Collins
0 siblings, 1 reply; 6+ messages in thread
From: OGAWA Hirofumi @ 2007-03-26 15:31 UTC (permalink / raw)
To: Hiroyuki Machida; +Cc: Paul Collins, linux-kernel
Hiroyuki Machida <Hiroyuki_Machida@hq.scei.sony.co.jp> writes:
> I'm not famillar with recent fat code, but code itself looks good for
> just turn on/off time adjusting. On the other hand, I feel we need more
> consideration on use cases/requirements. I feel that turning off
> time adjustment is a just ad-hoc solution to issues like Paul san
> brought up.
Thank you. I see. So we need "timezone" option to specify adjusted
time? If so, I feel we can add it as "timezone=utc", then it'll can
be improved later...
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps
2007-03-26 15:31 ` OGAWA Hirofumi
@ 2007-03-27 9:52 ` Paul Collins
2007-03-27 15:40 ` OGAWA Hirofumi
0 siblings, 1 reply; 6+ messages in thread
From: Paul Collins @ 2007-03-27 9:52 UTC (permalink / raw)
To: OGAWA Hirofumi; +Cc: Hiroyuki Machida, linux-kernel
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> writes:
> Hiroyuki Machida <Hiroyuki_Machida@hq.scei.sony.co.jp> writes:
>
>> I'm not famillar with recent fat code, but code itself looks good for
>> just turn on/off time adjusting. On the other hand, I feel we need more
>> consideration on use cases/requirements. I feel that turning off
>> time adjustment is a just ad-hoc solution to issues like Paul san
>> brought up.
>
> Thank you. I see. So we need "timezone" option to specify adjusted
> time? If so, I feel we can add it as "timezone=utc", then it'll can
> be improved later...
I am happy to change the patch as needed. However, since the kernel
does not have access to a timezone database and therefore cannot
convert timezone names to offsets, perhaps the mount option should be
something like "tzoffset=0", "tzoffset=1200" etc., with "tzoffset=0"
being equivalent to the "posixtime" option implemented by my patch.
--
Paul Collins
Wellington, New Zealand
Dag vijandelijk luchtschip de huismeester is dood
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps
2007-03-27 9:52 ` Paul Collins
@ 2007-03-27 15:40 ` OGAWA Hirofumi
0 siblings, 0 replies; 6+ messages in thread
From: OGAWA Hirofumi @ 2007-03-27 15:40 UTC (permalink / raw)
To: Paul Collins; +Cc: Hiroyuki Machida, linux-kernel
Paul Collins <paul@briny.ondioline.org> writes:
> OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> writes:
>
>> Thank you. I see. So we need "timezone" option to specify adjusted
>> time? If so, I feel we can add it as "timezone=utc", then it'll can
>> be improved later...
>
> I am happy to change the patch as needed. However, since the kernel
> does not have access to a timezone database and therefore cannot
> convert timezone names to offsets, perhaps the mount option should be
> something like "tzoffset=0", "tzoffset=1200" etc., with "tzoffset=0"
> being equivalent to the "posixtime" option implemented by my patch.
Looks sane. The mount command would be able to convert the string
timezone to it if needed.
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps
2007-03-19 11:35 Paul Collins
@ 2007-03-19 14:31 ` OGAWA Hirofumi
0 siblings, 0 replies; 6+ messages in thread
From: OGAWA Hirofumi @ 2007-03-19 14:31 UTC (permalink / raw)
To: Paul Collins; +Cc: linux-kernel, Hiroyuki_Machida
Paul Collins <paul@briny.ondioline.org> writes:
> Hello,
Hello,
> Here is a patch that adds a mount option named "posixtime" that, when
> enabled, causes the fat/vfat code to not adjust timestamps as they are
> read/written to/from disk. The intent of the adjustment as performed
> by the existing code appears to be to present correct timestamps to
> Windows and friends, which treat the timestamp values as local time.
>
> However, the systems that I use to update my FAT32 filesystems are all
> running Linux, and as such will process POSIX timestamps correctly.
> (The filesystems are on disks in digital audio players, which do not
> process timestamps except to check if they have changed.) Due to the
> aforementioned adjustment on read/write, after a Daylight Savings
> transition I must update the file timestamps on the filesystems so
> that rsync does not needlessly re-copy files.
>
> Please review and consider applying this patch.
Thanks. Looks good to me as start. IIRC, Machida-san did this few
years ago. Machida-san, do you have any comment?
> diff --git a/fs/fat/dir.c b/fs/fat/dir.c
> index c16af24..d6c0a7f 100644
> --- a/fs/fat/dir.c
> +++ b/fs/fat/dir.c
> @@ -1064,7 +1064,7 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
> goto error_free;
> }
>
> - fat_date_unix2dos(ts->tv_sec, &time, &date);
> + fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.adjust);
>
> de = (struct msdos_dir_entry *)bhs[0]->b_data;
> /* filling the new directory slots ("." and ".." entries) */
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index a9e4688..02d9225 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -374,17 +374,20 @@ static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
> inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
> & ~((loff_t)sbi->cluster_size - 1)) >> 9;
> inode->i_mtime.tv_sec =
> - date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date));
> + date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date),
> + sbi->options.adjust);
> inode->i_mtime.tv_nsec = 0;
> if (sbi->options.isvfat) {
> int secs = de->ctime_cs / 100;
> int csecs = de->ctime_cs % 100;
> inode->i_ctime.tv_sec =
> date_dos2unix(le16_to_cpu(de->ctime),
> - le16_to_cpu(de->cdate)) + secs;
> + le16_to_cpu(de->cdate),
> + sbi->options.adjust) + secs;
> inode->i_ctime.tv_nsec = csecs * 10000000;
> inode->i_atime.tv_sec =
> - date_dos2unix(0, le16_to_cpu(de->adate));
> + date_dos2unix(0, le16_to_cpu(de->adate),
> + sbi->options.adjust);
> inode->i_atime.tv_nsec = 0;
> } else
> inode->i_ctime = inode->i_atime = inode->i_mtime;
> @@ -592,11 +595,14 @@ retry:
> raw_entry->attr = fat_attr(inode);
> raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
> raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
> - fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
> + fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date,
> + sbi->options.adjust);
> if (sbi->options.isvfat) {
> __le16 atime;
> - fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
> - fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
> + fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate,
> + sbi->options.adjust);
> + fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate,
> + sbi->options.adjust);
> raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
> inode->i_ctime.tv_nsec / 10000000;
> }
> @@ -854,7 +860,7 @@ enum {
> Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
> Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
> Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
> - Opt_obsolate, Opt_flush, Opt_err,
> + Opt_obsolate, Opt_flush, Opt_posixtime, Opt_err,
> };
>
> static match_table_t fat_tokens = {
> @@ -887,6 +893,7 @@ static match_table_t fat_tokens = {
> {Opt_obsolate, "cvf_options=%100s"},
> {Opt_obsolate, "posix"},
> {Opt_flush, "flush"},
> + {Opt_posixtime, "posixtime"},
> {Opt_err, NULL},
> };
> static match_table_t msdos_tokens = {
> @@ -950,6 +957,7 @@ static int parse_options(char *options, int is_vfat, int silent, int *debug,
> opts->utf8 = opts->unicode_xlate = 0;
> opts->numtail = 1;
> opts->nocase = 0;
> + opts->adjust = 1;
> *debug = 0;
>
> if (!options)
> @@ -1032,6 +1040,10 @@ static int parse_options(char *options, int is_vfat, int silent, int *debug,
> opts->flush = 1;
> break;
>
> + case Opt_posixtime:
> + opts->adjust = 0;
> + break;
> +
> /* msdos specific */
> case Opt_dots:
> opts->dotsOK = 1;
> diff --git a/fs/fat/misc.c b/fs/fat/misc.c
> index 308f2b6..72a1a29 100644
> --- a/fs/fat/misc.c
> +++ b/fs/fat/misc.c
> @@ -143,7 +143,7 @@ static int day_n[] = {
> };
>
> /* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */
> -int date_dos2unix(unsigned short time, unsigned short date)
> +int date_dos2unix(unsigned short time, unsigned short date, int adjust)
> {
> int month, year, secs;
>
> @@ -157,16 +157,18 @@ int date_dos2unix(unsigned short time, unsigned short date)
> ((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 &&
> month < 2 ? 1 : 0)+3653);
> /* days since 1.1.70 plus 80's leap day */
> - secs += sys_tz.tz_minuteswest*60;
> + if (adjust)
> + secs += sys_tz.tz_minuteswest*60;
> return secs;
> }
>
> /* Convert linear UNIX date to a MS-DOS time/date pair. */
> -void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date)
> +void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date, int adjust)
> {
> int day, year, nl_day, month;
>
> - unix_date -= sys_tz.tz_minuteswest*60;
> + if (adjust)
> + unix_date -= sys_tz.tz_minuteswest*60;
>
> /* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
> if (unix_date < 315532800)
> diff --git a/fs/vfat/namei.c b/fs/vfat/namei.c
> index 0afd745..7e5487b 100644
> --- a/fs/vfat/namei.c
> +++ b/fs/vfat/namei.c
> @@ -626,7 +626,7 @@ shortname:
> memcpy(de->name, msdos_name, MSDOS_NAME);
> de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
> de->lcase = lcase;
> - fat_date_unix2dos(ts->tv_sec, &time, &date);
> + fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.adjust);
> de->time = de->ctime = time;
> de->date = de->cdate = de->adate = date;
> de->ctime_cs = 0;
> diff --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h
> index 24a9ef1..b3eeec8 100644
> --- a/include/linux/msdos_fs.h
> +++ b/include/linux/msdos_fs.h
> @@ -205,7 +205,8 @@ struct fat_mount_options {
> numtail:1, /* Does first alias have a numeric '~1' type tail? */
> atari:1, /* Use Atari GEMDOS variation of MS-DOS fs */
> flush:1, /* write things quickly */
> - nocase:1; /* Does this need case conversion? 0=need case conversion*/
> + nocase:1, /* Does this need case conversion? 0=need case conversion*/
> + adjust:1; /* Adjust time and date based on sys_tz?*/
> };
>
> #define FAT_HASH_BITS 8
> @@ -421,8 +422,8 @@ extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
> extern void fat_fs_panic(struct super_block *s, const char *fmt, ...);
> extern void fat_clusters_flush(struct super_block *sb);
> extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
> -extern int date_dos2unix(unsigned short time, unsigned short date);
> -extern void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date);
> +extern int date_dos2unix(unsigned short time, unsigned short date, int adjust);
> +extern void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date, int adjust);
> extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
>
> int fat_cache_init(void);
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps
@ 2007-03-19 11:35 Paul Collins
2007-03-19 14:31 ` OGAWA Hirofumi
0 siblings, 1 reply; 6+ messages in thread
From: Paul Collins @ 2007-03-19 11:35 UTC (permalink / raw)
To: OGAWA Hirofumi; +Cc: linux-kernel
Hello,
Here is a patch that adds a mount option named "posixtime" that, when
enabled, causes the fat/vfat code to not adjust timestamps as they are
read/written to/from disk. The intent of the adjustment as performed
by the existing code appears to be to present correct timestamps to
Windows and friends, which treat the timestamp values as local time.
However, the systems that I use to update my FAT32 filesystems are all
running Linux, and as such will process POSIX timestamps correctly.
(The filesystems are on disks in digital audio players, which do not
process timestamps except to check if they have changed.) Due to the
aforementioned adjustment on read/write, after a Daylight Savings
transition I must update the file timestamps on the filesystems so
that rsync does not needlessly re-copy files.
Please review and consider applying this patch.
Signed-off-by: Paul Collins <paul@ondioline.org>
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index c16af24..d6c0a7f 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -1064,7 +1064,7 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
goto error_free;
}
- fat_date_unix2dos(ts->tv_sec, &time, &date);
+ fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.adjust);
de = (struct msdos_dir_entry *)bhs[0]->b_data;
/* filling the new directory slots ("." and ".." entries) */
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index a9e4688..02d9225 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -374,17 +374,20 @@ static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
& ~((loff_t)sbi->cluster_size - 1)) >> 9;
inode->i_mtime.tv_sec =
- date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date));
+ date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date),
+ sbi->options.adjust);
inode->i_mtime.tv_nsec = 0;
if (sbi->options.isvfat) {
int secs = de->ctime_cs / 100;
int csecs = de->ctime_cs % 100;
inode->i_ctime.tv_sec =
date_dos2unix(le16_to_cpu(de->ctime),
- le16_to_cpu(de->cdate)) + secs;
+ le16_to_cpu(de->cdate),
+ sbi->options.adjust) + secs;
inode->i_ctime.tv_nsec = csecs * 10000000;
inode->i_atime.tv_sec =
- date_dos2unix(0, le16_to_cpu(de->adate));
+ date_dos2unix(0, le16_to_cpu(de->adate),
+ sbi->options.adjust);
inode->i_atime.tv_nsec = 0;
} else
inode->i_ctime = inode->i_atime = inode->i_mtime;
@@ -592,11 +595,14 @@ retry:
raw_entry->attr = fat_attr(inode);
raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
- fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
+ fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date,
+ sbi->options.adjust);
if (sbi->options.isvfat) {
__le16 atime;
- fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
- fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
+ fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate,
+ sbi->options.adjust);
+ fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate,
+ sbi->options.adjust);
raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
inode->i_ctime.tv_nsec / 10000000;
}
@@ -854,7 +860,7 @@ enum {
Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
- Opt_obsolate, Opt_flush, Opt_err,
+ Opt_obsolate, Opt_flush, Opt_posixtime, Opt_err,
};
static match_table_t fat_tokens = {
@@ -887,6 +893,7 @@ static match_table_t fat_tokens = {
{Opt_obsolate, "cvf_options=%100s"},
{Opt_obsolate, "posix"},
{Opt_flush, "flush"},
+ {Opt_posixtime, "posixtime"},
{Opt_err, NULL},
};
static match_table_t msdos_tokens = {
@@ -950,6 +957,7 @@ static int parse_options(char *options, int is_vfat, int silent, int *debug,
opts->utf8 = opts->unicode_xlate = 0;
opts->numtail = 1;
opts->nocase = 0;
+ opts->adjust = 1;
*debug = 0;
if (!options)
@@ -1032,6 +1040,10 @@ static int parse_options(char *options, int is_vfat, int silent, int *debug,
opts->flush = 1;
break;
+ case Opt_posixtime:
+ opts->adjust = 0;
+ break;
+
/* msdos specific */
case Opt_dots:
opts->dotsOK = 1;
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index 308f2b6..72a1a29 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -143,7 +143,7 @@ static int day_n[] = {
};
/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */
-int date_dos2unix(unsigned short time, unsigned short date)
+int date_dos2unix(unsigned short time, unsigned short date, int adjust)
{
int month, year, secs;
@@ -157,16 +157,18 @@ int date_dos2unix(unsigned short time, unsigned short date)
((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 &&
month < 2 ? 1 : 0)+3653);
/* days since 1.1.70 plus 80's leap day */
- secs += sys_tz.tz_minuteswest*60;
+ if (adjust)
+ secs += sys_tz.tz_minuteswest*60;
return secs;
}
/* Convert linear UNIX date to a MS-DOS time/date pair. */
-void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date)
+void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date, int adjust)
{
int day, year, nl_day, month;
- unix_date -= sys_tz.tz_minuteswest*60;
+ if (adjust)
+ unix_date -= sys_tz.tz_minuteswest*60;
/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
if (unix_date < 315532800)
diff --git a/fs/vfat/namei.c b/fs/vfat/namei.c
index 0afd745..7e5487b 100644
--- a/fs/vfat/namei.c
+++ b/fs/vfat/namei.c
@@ -626,7 +626,7 @@ shortname:
memcpy(de->name, msdos_name, MSDOS_NAME);
de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
de->lcase = lcase;
- fat_date_unix2dos(ts->tv_sec, &time, &date);
+ fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.adjust);
de->time = de->ctime = time;
de->date = de->cdate = de->adate = date;
de->ctime_cs = 0;
diff --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h
index 24a9ef1..b3eeec8 100644
--- a/include/linux/msdos_fs.h
+++ b/include/linux/msdos_fs.h
@@ -205,7 +205,8 @@ struct fat_mount_options {
numtail:1, /* Does first alias have a numeric '~1' type tail? */
atari:1, /* Use Atari GEMDOS variation of MS-DOS fs */
flush:1, /* write things quickly */
- nocase:1; /* Does this need case conversion? 0=need case conversion*/
+ nocase:1, /* Does this need case conversion? 0=need case conversion*/
+ adjust:1; /* Adjust time and date based on sys_tz?*/
};
#define FAT_HASH_BITS 8
@@ -421,8 +422,8 @@ extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
extern void fat_fs_panic(struct super_block *s, const char *fmt, ...);
extern void fat_clusters_flush(struct super_block *sb);
extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
-extern int date_dos2unix(unsigned short time, unsigned short date);
-extern void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date);
+extern int date_dos2unix(unsigned short time, unsigned short date, int adjust);
+extern void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date, int adjust);
extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
int fat_cache_init(void);
--
Paul Collins
Wellington, New Zealand
Dag vijandelijk luchtschip de huismeester is dood
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2007-03-27 15:40 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-03-26 4:05 [PATCH] fat/vfat: optionally ignore system timezone offset when reading/writing timestamps Hiroyuki Machida
2007-03-26 15:31 ` OGAWA Hirofumi
2007-03-27 9:52 ` Paul Collins
2007-03-27 15:40 ` OGAWA Hirofumi
-- strict thread matches above, loose matches on Subject: below --
2007-03-19 11:35 Paul Collins
2007-03-19 14:31 ` OGAWA Hirofumi
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