The FAT filesystem partition volume label can be read with
FAT_IOCTL_GET_VOLUME_LABEL and written with FAT_IOCTL_SET_VOLUME_LABEL.
v3:
1. write volume label both boot sector and root directory.
v2:
1. add filesystem version check.
2. add diretory permissions check.
3. add volume label string check.
4. fixed part of return value.
5. fixed some indent issue.
6. remove sync_dirty_buffer().
Chen Guanqiao (2):
fs: fat: add fat filesystem partition volume label in local structure
fs: fat: add ioctl method in fat filesystem driver
fs/fat/fat.h | 1 +
fs/fat/file.c | 116 ++++++++++++++++++++++++++++++++++++++++++
fs/fat/inode.c | 15 ++++--
include/uapi/linux/msdos_fs.h | 2 +
4 files changed, 131 insertions(+), 3 deletions(-)
--
2.15.1
Signed-off-by: Chen Guanqiao <[email protected]>
---
fs/fat/fat.h | 1 +
fs/fat/inode.c | 15 ++++++++++++---
include/uapi/linux/msdos_fs.h | 2 ++
3 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 8fc1093da47d..204012c94421 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -86,6 +86,7 @@ struct msdos_sb_info {
int dir_per_block; /* dir entries per block */
int dir_per_block_bits; /* log2(dir_per_block) */
unsigned int vol_id; /*volume ID*/
+ char vol_label[11]; /*volume label*/
int fatent_shift;
const struct fatent_operations *fatent_ops;
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 20a0a89eaca5..a97b6314ef33 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -45,12 +45,14 @@ struct fat_bios_param_block {
u8 fat16_state;
u32 fat16_vol_id;
+ u8 fat16_vol_label[11];
u32 fat32_length;
u32 fat32_root_cluster;
u16 fat32_info_sector;
u8 fat32_state;
u32 fat32_vol_id;
+ u8 fat32_vol_label[11];
};
static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
@@ -1460,12 +1462,16 @@ static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
bpb->fat16_state = b->fat16.state;
bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
+ memcpy(bpb->fat16_vol_label, b->fat16.vol_label,
+ sizeof(bpb->fat16_vol_label));
bpb->fat32_length = le32_to_cpu(b->fat32.length);
bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
bpb->fat32_state = b->fat32.state;
bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
+ memcpy(bpb->fat32_vol_label, b->fat32.vol_label,
+ sizeof(bpb->fat32_vol_label));
/* Validate this looks like a FAT filesystem BPB */
if (!bpb->fat_reserved) {
@@ -1723,11 +1729,14 @@ 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)
+ /* interpret volume ID and label as a little endian 32 bit integer */
+ if (sbi->fat_bits == 32) {
sbi->vol_id = bpb.fat32_vol_id;
- else /* fat 16 or 12 */
+ memcpy(sbi->vol_label, bpb.fat32_vol_label, sizeof(sbi->vol_label));
+ } else { /* fat 16 or 12 */
sbi->vol_id = bpb.fat16_vol_id;
+ memcpy(sbi->vol_label, bpb.fat16_vol_label, sizeof(sbi->vol_label));
+ }
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 a45d0754102e..90d2d6f3d908 100644
--- a/include/uapi/linux/msdos_fs.h
+++ b/include/uapi/linux/msdos_fs.h
@@ -107,6 +107,8 @@ struct __fat_dirent {
#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)
+#define FAT_IOCTL_GET_VOLUME_LABEL _IOR('r', 0x14, __u8[11])
+#define FAT_IOCTL_SET_VOLUME_LABEL _IOW('r', 0x15, __u8[11])
struct fat_boot_sector {
__u8 ignored[3]; /* Boot strap short or near jump */
--
2.15.1
Signed-off-by: Chen Guanqiao <[email protected]>
---
fs/fat/file.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 116 insertions(+)
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 4724cc9ad650..972f9aed5b46 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -20,6 +20,25 @@
static long fat_fallocate(struct file *file, int mode,
loff_t offset, loff_t len);
+static int fat_check_volume_label(const char *label)
+{
+ int i;
+
+ for (i=0; i<11; ++i) {
+ switch (label[i]) {
+ case 0x20:
+ case 'A' ... 'Z':
+ case '0' ... '9':
+ continue;
+ case 0:
+ return 0;
+ default:
+ return -EINVAL;
+ }
+ }
+ return -EINVAL;
+}
+
static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
{
u32 attr;
@@ -121,10 +140,103 @@ static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
return put_user(sbi->vol_id, user_attr);
}
+static int fat_ioctl_get_volume_label(struct inode *inode,
+ u8 __user *vol_label)
+{
+ int ret = 0;
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+
+ if (copy_to_user(vol_label, sbi->vol_label, sizeof(sbi->vol_label)))
+ ret = -EFAULT;
+
+ return ret;
+}
+
+static int fat_ioctl_set_volume_label(struct file *file,
+ u8 __user *vol_label)
+{
+ int err;
+ u8 label[11];
+ struct buffer_head *bh;
+ struct fat_boot_sector *b;
+ struct msdos_dir_entry *entry;
+ struct inode *inode = file_inode(file);
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ if (copy_from_user(label, vol_label, sizeof(label))) {
+ err = -EFAULT;
+ goto out;
+ }
+
+ if (fat_check_volume_label(label)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ err = mnt_want_write_file(file);
+ if (err)
+ goto out;
+
+ inode_lock(inode);
+
+ if (sb_rdonly(inode->i_sb)) {
+ err = -EROFS;
+ goto out_unlock_inode;
+ }
+
+ /* handling sector's vol_label */
+ bh = sb_bread(inode->i_sb, 0);
+ if (bh == NULL) {
+ fat_msg(inode->i_sb, KERN_ERR,
+ "unable to read boot sector to write volume label");
+ err = -EFAULT;
+ goto out_unlock_inode;
+ }
+
+ b = (struct fat_boot_sector *) bh->b_data;
+
+ if (b->fat16.signature == 0x28 || b->fat32.signature == 0x28) {
+ fat_msg(inode->i_sb, KERN_ERR,
+ "volume label supported since OS/2 1.2 and MS-DOS 4.0 "
+ "and higher");
+ err = -EFAULT;
+ goto out_unlock_inode;
+ }
+
+ lock_buffer(bh);
+ if (sbi->fat_bits == 32)
+ memcpy(b->fat32.vol_label, label, sizeof(label));
+ else
+ memcpy(b->fat16.vol_label, label, sizeof(label));
+
+ mark_buffer_dirty(bh);
+ unlock_buffer(bh);
+ brelse(bh);
+
+ /* handling root directory's vol_label */
+ bh = sb_bread(sb, sbi->dir_start);
+ entry = &((struct msdos_dir_entry *)(bh->b_data))[0];
+
+ lock_buffer(bh);
+ memcpy(entry->name, label, sizeof(entry->name));
+ mark_buffer_dirty(bh);
+ unlock_buffer(bh);
+ brelse(bh);
+
+ memcpy(sbi->vol_label, label, sizeof(sbi->vol_label));
+
+ out_unlock_inode:
+ inode_unlock(inode);
+ out:
+ return err;
+}
+
long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
u32 __user *user_attr = (u32 __user *)arg;
+ u8 __user *user_vol_label = (u8 __user *)arg;
switch (cmd) {
case FAT_IOCTL_GET_ATTRIBUTES:
@@ -133,6 +245,10 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return fat_ioctl_set_attributes(filp, user_attr);
case FAT_IOCTL_GET_VOLUME_ID:
return fat_ioctl_get_volume_id(inode, user_attr);
+ case FAT_IOCTL_GET_VOLUME_LABEL:
+ return fat_ioctl_get_volume_label(inode, user_vol_label);
+ case FAT_IOCTL_SET_VOLUME_LABEL:
+ return fat_ioctl_set_volume_label(filp, user_vol_label);
default:
return -ENOTTY; /* Inappropriate ioctl for device */
}
--
2.15.1
Chen Guanqiao <[email protected]> writes:
> +static int fat_check_volume_label(const char *label)
> +{
> + int i;
> +
> + for (i=0; i<11; ++i) {
> + switch (label[i]) {
> + case 0x20:
> + case 'A' ... 'Z':
> + case '0' ... '9':
> + continue;
> + case 0:
> + return 0;
> + default:
> + return -EINVAL;
> + }
> + }
> + return -EINVAL;
> +}
This check is really work? Especially what Windows show if '\0' is
included in label?
> +static int fat_ioctl_get_volume_label(struct inode *inode,
> + u8 __user *vol_label)
> +{
> + int ret = 0;
> + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
> +
> + if (copy_to_user(vol_label, sbi->vol_label, sizeof(sbi->vol_label)))
> + ret = -EFAULT;
> +
> + return ret;
> +}
This should handle the label in root dir too.
> + inode_lock(inode);
Lock is not enough.
> + if (sb_rdonly(inode->i_sb)) {
> + err = -EROFS;
> + goto out_unlock_inode;
> + }
mnt_want_write_file() checks it already.
> + /* handling sector's vol_label */
> + bh = sb_bread(inode->i_sb, 0);
> + if (bh == NULL) {
> + fat_msg(inode->i_sb, KERN_ERR,
> + "unable to read boot sector to write volume label");
> + err = -EFAULT;
-EIO
> + if (b->fat16.signature == 0x28 || b->fat32.signature == 0x28) {
> + fat_msg(inode->i_sb, KERN_ERR,
> + "volume label supported since OS/2 1.2 and MS-DOS 4.0 "
> + "and higher");
> + err = -EFAULT;
> + goto out_unlock_inode;
> + }
I don't know though, is this check necessary?
> + /* handling root directory's vol_label */
> + bh = sb_bread(sb, sbi->dir_start);
> + entry = &((struct msdos_dir_entry *)(bh->b_data))[0];
> +
> + lock_buffer(bh);
> + memcpy(entry->name, label, sizeof(entry->name));
> + mark_buffer_dirty(bh);
> + unlock_buffer(bh);
> + brelse(bh);
This totally doesn't work. Please check other implementations how to
handle label.
> + out_unlock_inode:
> + inode_unlock(inode);
Missing release mnt_want_write_file().
Thanks.