fatfs: add FAT_IOCTL_GET_VOLUME_ID
This patch, originally from Android kernel, adds vfat ioctl command
FAT_IOCTL_GET_VOLUME_ID, with this command we can get the vfat volume ID
using following code:
ioctl(fd, 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.
Android uses vfat volume ID to identify different sd card, when a new sd
card is inserted to device, android can scan the media on it and pop up
new contents.
Signed-off-by: Bintian Wang <bintian.wang@linaro.org>
Cc: dmitry pervushin <dpervushin@gmail.com>
Cc: Mike Lockwood <lockwood@android.com>
Cc: Colin Cross <ccross@android.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Sean McNeil <sean@mcneil.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/uapi/linux/msdos_fs.h b/include/uapi/linux/msdos_fs.h
index f055e58..e284ff9 100644
--- a/include/uapi/linux/msdos_fs.h
+++ b/include/uapi/linux/msdos_fs.h
@@ -104,6 +104,8 @@
/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
#define FAT_IOCTL_GET_ATTRIBUTES _IOR('r', 0x10, __u32)
#define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32)
+/*Android kernel has used 0x12, so we use 0x13*/
+#define FAT_IOCTL_GET_VOLUME_ID _IOR('r', 0x13, __u32)
struct fat_boot_sector {
__u8 ignored[3]; /* Boot strap short or near jump */
@@ -128,6 +130,10 @@
__u8 drive_number; /* Physical drive number */
__u8 state; /* undocumented, but used
for mount state. */
+ __u8 signature; /* extended boot signature */
+ __u8 vol_id[4]; /* volume ID */
+ __u8 vol_label[11]; /* volume label */
+ __u8 fs_type[8]; /* file system type */
/* other fiealds are not added here */
} fat16;
@@ -147,6 +153,10 @@
__u8 drive_number; /* Physical drive number */
__u8 state; /* undocumented, but used
for mount state. */
+ __u8 signature; /* extended boot signature */
+ __u8 vol_id[4]; /* volume ID */
+ __u8 vol_label[11]; /* volume label */
+ __u8 fs_type[8]; /* file system type */
/* other fiealds are not added here */
} fat32;
};