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FAT: Add new ioctl VFAT_IOCTL_GET_VOLUME_ID for reading the volume ID.

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Signed-off-by: Brian Swetland <swetland@google.com>
This commit is contained in:
Mike Lockwood
2008-03-15 13:29:36 -04:00
committed by Colin Cross
parent 807e5f6486
commit ac7333371d
4 changed files with 31 additions and 0 deletions
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9
fs/fat/dir.c
View File

@@ -754,6 +754,13 @@ static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
return ret; return ret;
} }
static int fat_ioctl_volume_id(struct inode *dir)
{
struct super_block *sb = dir->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
return sbi->vol_id;
}
static long fat_dir_ioctl(struct file *filp, unsigned int cmd, static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg) unsigned long arg)
{ {
@@ -770,6 +777,8 @@ static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
short_only = 0; short_only = 0;
both = 1; both = 1;
break; break;
case VFAT_IOCTL_GET_VOLUME_ID:
return fat_ioctl_volume_id(inode);
default: default:
return fat_generic_ioctl(filp, cmd, arg); return fat_generic_ioctl(filp, cmd, arg);
} }

1
fs/fat/fat.h
View File

@@ -78,6 +78,7 @@ struct msdos_sb_info {
const void *dir_ops; /* Opaque; default directory operations */ const void *dir_ops; /* Opaque; default directory operations */
int dir_per_block; /* dir entries per block */ int dir_per_block; /* dir entries per block */
int dir_per_block_bits; /* log2(dir_per_block) */ int dir_per_block_bits; /* log2(dir_per_block) */
unsigned long vol_id; /* volume ID */
int fatent_shift; int fatent_shift;
struct fatent_operations *fatent_ops; struct fatent_operations *fatent_ops;

9
fs/fat/inode.c
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@@ -1245,6 +1245,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
struct inode *root_inode = NULL, *fat_inode = NULL; struct inode *root_inode = NULL, *fat_inode = NULL;
struct buffer_head *bh; struct buffer_head *bh;
struct fat_boot_sector *b; struct fat_boot_sector *b;
struct fat_boot_bsx *bsx;
struct msdos_sb_info *sbi; struct msdos_sb_info *sbi;
u16 logical_sector_size; u16 logical_sector_size;
u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
@@ -1390,6 +1391,8 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
goto out_fail; goto out_fail;
} }
bsx = (struct fat_boot_bsx *)(bh->b_data + FAT32_BSX_OFFSET);
fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
if (!IS_FSINFO(fsinfo)) { if (!IS_FSINFO(fsinfo)) {
fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: " fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
@@ -1405,8 +1408,14 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
} }
brelse(fsinfo_bh); brelse(fsinfo_bh);
} else {
bsx = (struct fat_boot_bsx *)(bh->b_data + FAT16_BSX_OFFSET);
} }
/* interpret volume ID as a little endian 32 bit integer */
sbi->vol_id = (((u32)bsx->vol_id[0]) | ((u32)bsx->vol_id[1] << 8) |
((u32)bsx->vol_id[2] << 16) | ((u32)bsx->vol_id[3] << 24));
sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;

12
include/linux/msdos_fs.h
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@@ -101,6 +101,7 @@ struct __fat_dirent {
/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */ /* <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_GET_ATTRIBUTES _IOR('r', 0x10, __u32)
#define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32) #define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32)
#define VFAT_IOCTL_GET_VOLUME_ID _IOR('r', 0x12, __u32)
struct fat_boot_sector { struct fat_boot_sector {
__u8 ignored[3]; /* Boot strap short or near jump */ __u8 ignored[3]; /* Boot strap short or near jump */
@@ -138,6 +139,17 @@ struct fat_boot_fsinfo {
__le32 reserved2[4]; __le32 reserved2[4];
}; };
struct fat_boot_bsx {
__u8 drive; /* drive number */
__u8 reserved1;
__u8 signature; /* extended boot signature */
__u8 vol_id[4]; /* volume ID */
__u8 vol_label[11]; /* volume label */
__u8 type[8]; /* file system type */
};
#define FAT16_BSX_OFFSET 36 /* offset of fat_boot_bsx in FAT12 and FAT16 */
#define FAT32_BSX_OFFSET 64 /* offset of fat_boot_bsx in FAT32 */
struct msdos_dir_entry { struct msdos_dir_entry {
__u8 name[MSDOS_NAME];/* name and extension */ __u8 name[MSDOS_NAME];/* name and extension */
__u8 attr; /* attribute bits */ __u8 attr; /* attribute bits */