Re: [RFC][patch] filesystem: Vmufat filesystem, version 4

Pavel Machek
2009-04-24T22:12:09Z

On Mon 2009-04-13 21:32:48, Adrian McMenamin wrote:
> I know this still has issues that others have raised but I wanted to
> post a version before the end of the long weekend...
>
> As before - some documentation about the filesystem:
> http://mc.pp.se/dc/vms/flashmem.html
>
> A shell filesystem (eg for mount over loopback) available here:
> http://newgolddream.dyndns.info/pristine
>
> A few people commented that this is a bit long for a single file - but
> it is comparable to other files in the filesystem hierarchy - comments
> welcome.
>
> The filesystem is hardware independent but is also written on the basis
> that this is most likely to be used with a Dreamcast VMU - though it may
> be of more use to emulator writers in the end.
>
> fs/Kconfig | 1 +
> fs/Makefile | 1 +
> fs/vmufat/Kconfig | 14 +
> fs/vmufat/Makefile | 7 +
> fs/vmufat/inode.c | 1362 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 1385 insertions(+), 0 deletions(-)
>
> Signed-off-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
> ---
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 9f7270f..b7cb23d 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -176,6 +176,7 @@ source "fs/romfs/Kconfig"
> source "fs/sysv/Kconfig"
> source "fs/ufs/Kconfig"
> source "fs/exofs/Kconfig"
> +source "fs/vmufat/Kconfig"
>
> config NILFS2_FS
> tristate "NILFS2 file system support (EXPERIMENTAL)"
> diff --git a/fs/Makefile b/fs/Makefile
> index af6d047..9d2d469 100644
> --- a/fs/Makefile
> +++ b/fs/Makefile
> @@ -124,3 +124,4 @@ obj-$(CONFIG_OCFS2_FS) += ocfs2/
> obj-$(CONFIG_BTRFS_FS) += btrfs/
> obj-$(CONFIG_GFS2_FS) += gfs2/
> obj-$(CONFIG_EXOFS_FS) += exofs/
> +obj-$(CONFIG_VMUFAT_FS) += vmufat/
> diff --git a/fs/vmufat/Kconfig b/fs/vmufat/Kconfig
> new file mode 100644
> index 0000000..bdad4c6
> --- /dev/null
> +++ b/fs/vmufat/Kconfig
> @@ -0,0 +1,14 @@
> +config VMUFAT_FS
> + tristate "Dreamcast VMU FAT filesystem"
> + depends on BLOCK
> + help
> + This implements the simple FAT type filesystem found on SEGA
> + Dreamcast visual memory units.
> +
> + Dreamcast users who want to mount their VMUs to view the native
> + filesystem will say 'Y' here. The filesystem is hardware independent
> + but is not recommended for any serious use in other circumstances, so
> + just about everyone else should say 'N'.
> +
> + To compile this as a module say 'M' here. The module will be called
> + vmufat

"vmufat.ko." ?

> +static unsigned long vmufat_save_bcd(char *bh, int z)
> +{
> + unsigned char day, year, century, nl_day, month;
> + unsigned char u8year;

u8year? Should this be "u8 u8year"?

> + unsigned long unix_date = CURRENT_TIME.tv_sec;
> +
> + day = unix_date / 86400 - 3652;
> + year = day / 365;
> +
> + if ((year + 3) / 4 + 365 * year > day)
> + year--;
> +
> + day -= (year + 3) / 4 + 365 * year;
> + if (day == 59 && !(year & 3)) {
> + nl_day = day;
> + month = 2;
> + } else {
> + nl_day = (year & 3) || day <= 59 ? day : day - 1;
> + for (month = 0; month < 12; month++)
> + if (day_n[month] > nl_day)
> + break;
> + }
> +
> + century = 19;
> + if (year > 19)
> + century = 20;
> +
> + bh[z + 0x10] = bin2bcd(century);
> + u8year = year + 80;
> + if (u8year > 99)
> + u8year = u8year - 100;

It would be nice to document when this stops working.

> + bh[z + 0x11] = bin2bcd(u8year);
> + bh[z + 0x12] = bin2bcd(month);
> + bh[z + 0x13] =
> + bin2bcd(day - day_n[month - 1] + 1);
> + bh[z + 0x14] =
> + bin2bcd((unix_date / 3600) % 24);
> + bh[z + 0x15] = bin2bcd((unix_date / 60) % 60);
> + bh[z + 0x16] = bin2bcd(unix_date % 60);
> + return unix_date;
> +}
--
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