Messages in this thread | | | From | OGAWA Hirofumi <> | Subject | Re: [PATCH RFC] Add FAT_IOCTL_GET_VOLUME_ID | Date | Mon, 01 Jul 2013 15:12:22 +0900 |
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bintian.wang@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 <hirofumi@mail.parknet.co.jp>
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