[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]> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
