bintian.w...@linaro.org writes:
> This patch, originally from Android kernel, adds vfat directory ioctl command
> FAT_IOCTL_GET_VOLUME_ID, with this command we can get the vfat volume ID using
> following code:
>
> ioctl(dirfd(dir), FAT_IOCTL_GET_VOLUME_ID, &volume_ID)
>
> This patch is a modified version of the patch by Mike Lockwood, with changes
> from Dmitry Pervushin, who noticed the original patch makes some volume IDs
> abiguous with error returns: for example, if volume id is 0xFFFFFDAD, that
> matches -ENOIOCTLCMD, we get "FFFFFFFF" from the user space.
>
> So add a parameter to ioctl to get the correct volume ID.
Adding more specific usage example to changelog would help for
understanding this.
> + case FAT_IOCTL_GET_VOLUME_ID:
> + id = fat_ioctl_volume_id(inode);
> + return copy_to_user((unsigned int *)arg, &id, sizeof(id));
> + case FAT_IOCTL_GET_VOLUME_ID:
> + id = fat_ioctl_volume_id(inode);
> + return copy_to_user((unsigned int *)arg, &id, sizeof(id));
This pattern seems to from put_user().
Unnecessary cast of 1st arg. And copy_to_user() returns remaining bytes
when fail (not error code).
> +struct fat_boot_bsx {
> + __u8 drive; /* drive number */
> + __u8 reserved1;
> + __u8 signature; /* extended boot signature */
> + __u8 vol_id[4]; /* volume ID */
> + __u8 vol_label[11]; /* volume label */
> + __u8 type[8]; /* file system type */
> +};
> +#define FAT16_BSX_OFFSET 36 /* offset of fat_boot_bsx in FAT12 and FAT16 */
> +#define FAT32_BSX_OFFSET 64 /* offset of fat_boot_bsx in FAT32 */
There is any issue to merge those to "struct fat_boot_sector"? I guess,
merging it is cleaner way.
Thanks.
--
OGAWA Hirofumi <hirof...@mail.parknet.co.jp>
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