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authorMike Lockwood <lockwood@android.com>2013-07-08 16:00:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-09 10:33:25 -0700
commit6e5b93ee55d401f1619092fb675b57c28c9ed7ec (patch)
treed6d9627ec023d7375d8dc996523509ee45d082bd
parent4e80b1880c5a31d051d1e4a7377dec0a20701c23 (diff)
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>
-rw-r--r--fs/fat/fat.h1
-rw-r--r--fs/fat/file.c8
-rw-r--r--fs/fat/inode.c12
-rw-r--r--include/uapi/linux/msdos_fs.h10
4 files changed, 31 insertions, 0 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 21664fcf3616..4241e6f39e86 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 b0b632e50ddb..9b104f543056 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 5d4513cb1b3c..11b51bb55b42 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 f055e58b3147..e284ff919d6e 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;
};