Add support for reading / writing to the exfat volume label from the
FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls
Signed-off-by: Ethan Ferguson <ethan.ferguson@xxxxxxxxxx>
---
fs/exfat/exfat_fs.h | 7 ++
fs/exfat/exfat_raw.h | 6 ++
fs/exfat/file.c | 80 +++++++++++++++++++++
fs/exfat/namei.c | 2 +-
fs/exfat/super.c | 165 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 259 insertions(+), 1 deletion(-)
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index f8ead4d47ef0..a11a086c9d09 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -431,6 +431,10 @@ static inline loff_t exfat_ondisk_size(const struct inode *inode)
/* super.c */
int exfat_set_volume_dirty(struct super_block *sb);
int exfat_clear_volume_dirty(struct super_block *sb);
+int exfat_read_volume_label(struct super_block *sb,
+ struct exfat_uni_name *label_out);
+int exfat_write_volume_label(struct super_block *sb,
+ struct exfat_uni_name *label);
/* fatent.c */
#define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
@@ -477,6 +481,9 @@ int exfat_force_shutdown(struct super_block *sb, u32 flags);
/* namei.c */
extern const struct dentry_operations exfat_dentry_ops;
extern const struct dentry_operations exfat_utf8_dentry_ops;
+int exfat_find_empty_entry(struct inode *inode,
+ struct exfat_chain *p_dir, int num_entries,
+ struct exfat_entry_set_cache *es);
/* cache.c */
int exfat_cache_init(void);
diff --git a/fs/exfat/exfat_raw.h b/fs/exfat/exfat_raw.h
index 971a1ccd0e89..4082fa7b8c14 100644
--- a/fs/exfat/exfat_raw.h
+++ b/fs/exfat/exfat_raw.h
@@ -80,6 +80,7 @@
#define BOOTSEC_OLDBPB_LEN 53
#define EXFAT_FILE_NAME_LEN 15
+#define EXFAT_VOLUME_LABEL_LEN 11
#define EXFAT_MIN_SECT_SIZE_BITS 9
#define EXFAT_MAX_SECT_SIZE_BITS 12
@@ -159,6 +160,11 @@ struct exfat_dentry {
__le32 start_clu;
__le64 size;
} __packed upcase; /* up-case table directory entry */
+ struct {
+ __u8 char_count;
+ __le16 volume_label[EXFAT_VOLUME_LABEL_LEN];
+ __u8 reserved[8];
+ } __packed volume_label; /* volume label directory entry */
struct {
__u8 flags;
__u8 vendor_guid[16];
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 538d2b6ac2ec..c44928c02474 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -486,6 +486,82 @@ static int exfat_ioctl_shutdown(struct super_block *sb, unsigned long arg)
return exfat_force_shutdown(sb, flags);
}
+static int exfat_ioctl_get_volume_label(struct super_block *sb, unsigned long arg)
+{
+ int ret;
+ char utf8[FSLABEL_MAX] = {0};
+ struct exfat_uni_name *uniname;
+
+ uniname = kmalloc(sizeof(struct exfat_uni_name), GFP_KERNEL);
+ if (!uniname)
+ return -ENOMEM;
+
+ ret = exfat_read_volume_label(sb, uniname);
+ if (ret < 0)
+ goto cleanup;
+
+ ret = exfat_utf16_to_nls(sb, uniname, utf8, FSLABEL_MAX);
+ if (ret < 0)
+ goto cleanup;
+
+ if (copy_to_user((char __user *)arg, utf8, FSLABEL_MAX)) {
+ ret = -EFAULT;
+ goto cleanup;
+ }
+
+ ret = 0;
+
+cleanup:
+ kfree(uniname);
+ return ret;
+}
+
+static int exfat_ioctl_set_volume_label(struct super_block *sb,
+ unsigned long arg)
+{
+ int ret, lossy;
+ char utf8[FSLABEL_MAX];
+ struct exfat_uni_name *uniname;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ uniname = kmalloc(sizeof(struct exfat_uni_name), GFP_KERNEL);
+ if (!uniname)
+ return -ENOMEM;
+
+ if (copy_from_user(utf8, (char __user *)arg, FSLABEL_MAX)) {
+ ret = -EFAULT;
+ goto cleanup;
+ }
+
+ if (utf8[0]) {
+ ret = exfat_nls_to_utf16(sb, utf8, strnlen(utf8, FSLABEL_MAX),
+ uniname, &lossy);
+ if (ret < 0) {
+ goto cleanup;
+ } else if (lossy & NLS_NAME_LOSSY) {
+ ret = -EINVAL;
+ goto cleanup;
+ }
+ } else {
+ uniname->name[0] = 0x0000;
+ uniname->name_len = 0;
+ }
+
+ if (uniname->name_len > EXFAT_VOLUME_LABEL_LEN) {
+ exfat_info(sb, "Volume label length too long, truncating");
+ uniname->name_len = EXFAT_VOLUME_LABEL_LEN;
+ uniname->name[EXFAT_VOLUME_LABEL_LEN] = 0x0000;
+ }
+
+ ret = exfat_write_volume_label(sb, uniname);
+
+cleanup:
+ kfree(uniname);
+ return ret;
+}
+
long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -500,6 +576,10 @@ long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return exfat_ioctl_shutdown(inode->i_sb, arg);
case FITRIM:
return exfat_ioctl_fitrim(inode, arg);
+ case FS_IOC_GETFSLABEL:
+ return exfat_ioctl_get_volume_label(inode->i_sb, arg);
+ case FS_IOC_SETFSLABEL:
+ return exfat_ioctl_set_volume_label(inode->i_sb, arg);
default:
return -ENOTTY;
}
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index f5f1c4e8a29f..eaa781d6263c 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -300,7 +300,7 @@ static int exfat_check_max_dentries(struct inode *inode)
* the directory entry index in p_dir is returned on succeeds
* -error code is returned on failure
*/
-static int exfat_find_empty_entry(struct inode *inode,
+int exfat_find_empty_entry(struct inode *inode,
struct exfat_chain *p_dir, int num_entries,
struct exfat_entry_set_cache *es)
{
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 8926e63f5bb7..0374e41b48a5 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -573,6 +573,171 @@ static int exfat_verify_boot_region(struct super_block *sb)
return 0;
}
+static int exfat_get_volume_label_ptrs(struct super_block *sb,
+ struct buffer_head **out_bh,
+ struct exfat_dentry **out_dentry,
+ bool create)
+{
+ int i, ret;
+ unsigned int type;
+ struct exfat_sb_info *sbi = EXFAT_SB(sb);
+ struct inode *root_inode = sb->s_root->d_inode;
+ struct exfat_inode_info *ei = EXFAT_I(root_inode);
+ struct exfat_entry_set_cache es;
+ struct exfat_chain clu;
+ struct exfat_dentry *ep, *overwrite_ep = NULL;
+ struct buffer_head *bh, *overwrite_bh = NULL;
+
+ clu.dir = sbi->root_dir;
+ clu.flags = ALLOC_FAT_CHAIN;
+
+ while (clu.dir != EXFAT_EOF_CLUSTER) {
+ for (i = 0; i < sbi->dentries_per_clu; i++) {
+ ep = exfat_get_dentry(sb, &clu, i, &bh);
+
+ if (!ep) {
+ ret = -EIO;
+ goto error;
+ }
+
+ type = exfat_get_entry_type(ep);
+ if ((type == TYPE_DELETED || type == TYPE_UNUSED)
+ && !overwrite_ep && create) {
+ overwrite_ep = ep;
+ overwrite_bh = bh;
+ continue;
+ }
+
+ if (type == TYPE_VOLUME) {
+ *out_bh = bh;
+ *out_dentry = ep;
+
+ brelse(overwrite_bh);
+ return 0;
+ }
+
+ brelse(bh);
+ }
+
+ if (exfat_get_next_cluster(sb, &(clu.dir))) {
+ ret = -EIO;
+ goto error;
+ }
+ }
+
+ if (!create) {
+ ret = -ENOENT;
+ goto error;
+ }
+
+
+ if (overwrite_ep) {
+ ep = overwrite_ep;
+ bh = overwrite_bh;
+ goto overwrite;
+ }
+
+ ret = exfat_find_empty_entry(root_inode, &clu, 1, &es);
+ if (ret < 0)
+ goto error;
+
+ ei->hint_femp.eidx = 0;
+ ei->hint_femp.count = sbi->dentries_per_clu;
+ ei->hint_femp.cur = clu;
+
+ ep = exfat_get_dentry_cached(&es, 0);
+ bh = es.bh[EXFAT_B_TO_BLK(es.start_off, sb)];
+ /* increment use counter so exfat_put_dentry_set doesn't free */
+ get_bh(bh);
+ ret = exfat_put_dentry_set(&es, false);
+ if (ret < 0) {
+ bforget(bh);
+ goto error;
+ }
+ ei->hint_femp.eidx++;
+ ei->hint_femp.count--;
+
+overwrite:
+
+ memset(ep, 0, sizeof(struct exfat_dentry));
+ ep->type = EXFAT_VOLUME;
+ *out_bh = bh;
+ *out_dentry = ep;
+ return 0;
+
+error:
+ *out_bh = NULL;
+ *out_dentry = NULL;
+ return ret;
+}
+
+int exfat_read_volume_label(struct super_block *sb, struct exfat_uni_name *label_out)
+{
+ int ret, i;
+ struct exfat_sb_info *sbi = EXFAT_SB(sb);
+ struct buffer_head *bh = NULL;
+ struct exfat_dentry *ep = NULL;
+
+ mutex_lock(&sbi->s_lock);
+
+ ret = exfat_get_volume_label_ptrs(sb, &bh, &ep, false);
+ // ENOENT signifies that a volume label dentry doesn't exist
+ // We will treat this as an empty volume label and not fail.
+ if (ret == -ENOENT) {
+ label_out->name[0] = 0x0000;
+ label_out->name_len = 0;
+ ret = 0;
+ } else if (ret < 0) {
+ goto cleanup;
+ } else {
+ for (i = 0; i < EXFAT_VOLUME_LABEL_LEN; i++)
+ label_out->name[i] = le16_to_cpu(ep->dentry.volume_label.volume_label[i]);
+ label_out->name_len = ep->dentry.volume_label.char_count;
+ }
+
+cleanup:
+ mutex_unlock(&sbi->s_lock);
+ brelse(bh);
+ return ret;
+}
+
+int exfat_write_volume_label(struct super_block *sb,
+ struct exfat_uni_name *label)
+{
+ int ret, i;
+ struct exfat_sb_info *sbi = EXFAT_SB(sb);
+ struct buffer_head *bh = NULL;
+ struct exfat_dentry *ep = NULL;
+
+ if (label->name_len > EXFAT_VOLUME_LABEL_LEN)
+ return -EINVAL;
+
+ mutex_lock(&sbi->s_lock);
+
+ ret = exfat_get_volume_label_ptrs(sb, &bh, &ep, true);
+ if (ret < 0)
+ goto cleanup;
+
+ for (i = 0; i < label->name_len; i++)
+ ep->dentry.volume_label.volume_label[i] =
+ cpu_to_le16(label->name[i]);
+ // Fill the rest of the str with 0x0000
+ for (; i < EXFAT_VOLUME_LABEL_LEN; i++)
+ ep->dentry.volume_label.volume_label[i] = 0x0000;
+
+ ep->dentry.volume_label.char_count = label->name_len;
+
+cleanup:
+ mutex_unlock(&sbi->s_lock);
+
+ if (bh) {
+ exfat_update_bh(bh, IS_DIRSYNC(sb->s_root->d_inode));
+ brelse(bh);
+ }
+
+ return ret;
+}
+
/* mount the file system volume */
static int __exfat_fill_super(struct super_block *sb,
struct exfat_chain *root_clu)
--
2.34.1
