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-rw-r--r--fs/fat/fat.h1
-rw-r--r--fs/fat/file.c8
-rw-r--r--fs/fat/inode.c12
3 files changed, 21 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;