From: Mike Lockwood <[email protected]>
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.
Cc: dmitry pervushin <[email protected]>
Cc: Mike Lockwood <[email protected]>
Cc: Colin Cross <[email protected]>
Cc: Android Kernel Team <[email protected]>
Cc: OGAWA Hirofumi <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Sean McNeil <[email protected]>
Signed-off-by: Bintian Wang <[email protected]>
---
fs/fat/fat.h | 1 +
fs/fat/file.c | 8 ++++++++
fs/fat/inode.c | 12 ++++++++++++
include/uapi/linux/msdos_fs.h | 10 ++++++++++
4 files changed, 31 insertions(+)
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 21664fc..4241e6f 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -86,6 +86,7 @@ struct msdos_sb_info {
const void *dir_ops; /* Opaque; default directory operations */
int dir_per_block; /* dir entries per block */
int dir_per_block_bits; /* log2(dir_per_block) */
+ unsigned int vol_id; /*volume ID*/
int fatent_shift;
struct fatent_operations *fatent_ops;
diff --git a/fs/fat/file.c b/fs/fat/file.c
index b0b632e..9b104f5 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -114,6 +114,12 @@ out:
return err;
}
+static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ return put_user(sbi->vol_id, user_attr);
+}
+
long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -124,6 +130,8 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return fat_ioctl_get_attributes(inode, user_attr);
case FAT_IOCTL_SET_ATTRIBUTES:
return fat_ioctl_set_attributes(filp, user_attr);
+ case FAT_IOCTL_GET_VOLUME_ID:
+ return fat_ioctl_get_volume_id(inode, user_attr);
default:
return -ENOTTY; /* Inappropriate ioctl for device */
}
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 5d4513c..11b51bb 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1415,6 +1415,18 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
brelse(fsinfo_bh);
}
+ /* interpret volume ID as a little endian 32 bit integer */
+ if (sbi->fat_bits == 32)
+ sbi->vol_id = (((u32)b->fat32.vol_id[0]) |
+ ((u32)b->fat32.vol_id[1] << 8) |
+ ((u32)b->fat32.vol_id[2] << 16) |
+ ((u32)b->fat32.vol_id[3] << 24));
+ else /* fat 16 or 12 */
+ sbi->vol_id = (((u32)b->fat16.vol_id[0]) |
+ ((u32)b->fat16.vol_id[1] << 8) |
+ ((u32)b->fat16.vol_id[2] << 16) |
+ ((u32)b->fat16.vol_id[3] << 24));
+
sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
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 @@ struct __fat_dirent {
/* <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 @@ struct fat_boot_sector {
__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 @@ struct fat_boot_sector {
__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;
};
--
1.7.9.5
[email protected] writes:
> From: Mike Lockwood <[email protected]>
>
> 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.
Acked-by: OGAWA Hirofumi <[email protected]>
Thanks.
> Cc: dmitry pervushin <[email protected]>
> Cc: Mike Lockwood <[email protected]>
> Cc: Colin Cross <[email protected]>
> Cc: Android Kernel Team <[email protected]>
> Cc: OGAWA Hirofumi <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: John Stultz <[email protected]>
> Cc: Sean McNeil <[email protected]>
>
> Signed-off-by: Bintian Wang <[email protected]>
> ---
> fs/fat/fat.h | 1 +
> fs/fat/file.c | 8 ++++++++
> fs/fat/inode.c | 12 ++++++++++++
> include/uapi/linux/msdos_fs.h | 10 ++++++++++
> 4 files changed, 31 insertions(+)
>
> diff --git a/fs/fat/fat.h b/fs/fat/fat.h
> index 21664fc..4241e6f 100644
> --- a/fs/fat/fat.h
> +++ b/fs/fat/fat.h
> @@ -86,6 +86,7 @@ struct msdos_sb_info {
> const void *dir_ops; /* Opaque; default directory operations */
> int dir_per_block; /* dir entries per block */
> int dir_per_block_bits; /* log2(dir_per_block) */
> + unsigned int vol_id; /*volume ID*/
>
> int fatent_shift;
> struct fatent_operations *fatent_ops;
> diff --git a/fs/fat/file.c b/fs/fat/file.c
> index b0b632e..9b104f5 100644
> --- a/fs/fat/file.c
> +++ b/fs/fat/file.c
> @@ -114,6 +114,12 @@ out:
> return err;
> }
>
> +static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
> +{
> + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
> + return put_user(sbi->vol_id, user_attr);
> +}
> +
> long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> struct inode *inode = file_inode(filp);
> @@ -124,6 +130,8 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> return fat_ioctl_get_attributes(inode, user_attr);
> case FAT_IOCTL_SET_ATTRIBUTES:
> return fat_ioctl_set_attributes(filp, user_attr);
> + case FAT_IOCTL_GET_VOLUME_ID:
> + return fat_ioctl_get_volume_id(inode, user_attr);
> default:
> return -ENOTTY; /* Inappropriate ioctl for device */
> }
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index 5d4513c..11b51bb 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -1415,6 +1415,18 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
> brelse(fsinfo_bh);
> }
>
> + /* interpret volume ID as a little endian 32 bit integer */
> + if (sbi->fat_bits == 32)
> + sbi->vol_id = (((u32)b->fat32.vol_id[0]) |
> + ((u32)b->fat32.vol_id[1] << 8) |
> + ((u32)b->fat32.vol_id[2] << 16) |
> + ((u32)b->fat32.vol_id[3] << 24));
> + else /* fat 16 or 12 */
> + sbi->vol_id = (((u32)b->fat16.vol_id[0]) |
> + ((u32)b->fat16.vol_id[1] << 8) |
> + ((u32)b->fat16.vol_id[2] << 16) |
> + ((u32)b->fat16.vol_id[3] << 24));
> +
> sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
> sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
>
> 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 @@ struct __fat_dirent {
> /* <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 @@ struct fat_boot_sector {
> __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 @@ struct fat_boot_sector {
> __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;
> };
--
OGAWA Hirofumi <[email protected]>