[PATCH v7 0/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[PATCH v7 0/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[Ethan Ferguson]

Add support for reading / writing to the exfat volume label from the
FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls.

Implemented in similar ways to other fs drivers, namely btrfs and ext4,
where the ioctls are performed on file inodes.

v7:
Accepted changes from Yuezhang Mo <Yuezhang.Mo@sony.com>
* More accurate hint femp setting
* Logic simplification
* Reduced buffer_head usage
v6:
Moved creating new volume label dentry out of
exfat_get_volume_label_ptrs.
Use exfat_find_empty_entry to allocate new volume label dentry.
Better usage of hint_femp.
Use ALLOC_FAT_CHAIN in root directory.
Only allocate new volume label dentry when the label length > 0.
Link: https://lore.kernel.org/all/20250908164028.31711-1-ethan.ferguson@zetier.com/
v5:
Change behavior to only allocate new cluster when no useable dentries
exist.
Leverage exfat_find_empty_entry to handle this behavior, and to set
inode size.
Update inode hint_femp to speed up later search efforts.
Link: https://lore.kernel.org/all/20250903183322.191136-1-ethan.ferguson@zetier.com/
v4:
Implement allocating a new cluster when the current dentry cluster would
be full as a result of inserting a volume label dentry.
Link: https://lore.kernel.org/all/20250822202010.232922-1-ethan.ferguson@zetier.com/
v3:
Add lazy-loading of volume label into superblock.
Use better UTF-16 conversions to detect invalid characters.
If no volume label entry exists, overwrite a deleted dentry,
or create a new dentry if the cluster has space.
Link: https://lore.kernel.org/all/20250821150926.1025302-1-ethan.ferguson@zetier.com/
v2:
Fix endianness conversion as reported by kernel test robot
Link: https://lore.kernel.org/all/20250817003046.313497-1-ethan.ferguson@zetier.com/
v1:
Link: https://lore.kernel.org/all/20250815171056.103751-1-ethan.ferguson@zetier.com/

Ethan Ferguson (1):
  exfat: Add support for FS_IOC_{GET,SET}FSLABEL

 fs/exfat/dir.c       | 158 +++++++++++++++++++++++++++++++++++++++++++
 fs/exfat/exfat_fs.h  |   7 ++
 fs/exfat/exfat_raw.h |   6 ++
 fs/exfat/file.c      |  52 ++++++++++++++
 fs/exfat/namei.c     |   2 +-
 5 files changed, 224 insertions(+), 1 deletion(-)

-- 
2.34.1

[PATCH v7 1/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[Ethan Ferguson]

Add support for reading / writing to the exfat volume label from the
FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls

Co-developed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Ethan Ferguson <ethan.ferguson@zetier.com>
---
 fs/exfat/dir.c       | 158 +++++++++++++++++++++++++++++++++++++++++++
 fs/exfat/exfat_fs.h  |   7 ++
 fs/exfat/exfat_raw.h |   6 ++
 fs/exfat/file.c      |  52 ++++++++++++++
 fs/exfat/namei.c     |   2 +-
 5 files changed, 224 insertions(+), 1 deletion(-)

diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index ee060e26f51d..55d826f6475d 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -1244,3 +1244,161 @@ int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
 
 	return count;
 }
+
+static int exfat_get_volume_label_dentry(struct super_block *sb,
+		struct exfat_entry_set_cache *es)
+{
+	int i;
+	int dentry = 0;
+	unsigned int type;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_hint_femp hint_femp;
+	struct exfat_inode_info *ei = EXFAT_I(sb->s_root->d_inode);
+	struct exfat_chain clu;
+	struct exfat_dentry *ep;
+	struct buffer_head *bh;
+
+	hint_femp.eidx = EXFAT_HINT_NONE;
+	exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+
+	while (clu.dir != EXFAT_EOF_CLUSTER) {
+		for (i = 0; i < sbi->dentries_per_clu; i++, dentry++) {
+			ep = exfat_get_dentry(sb, &clu, i, &bh);
+			if (!ep)
+				return -EIO;
+
+			type = exfat_get_entry_type(ep);
+			if (hint_femp.eidx == EXFAT_HINT_NONE) {
+				if (type == TYPE_DELETED || type == TYPE_UNUSED) {
+					hint_femp.cur = clu;
+					hint_femp.eidx = dentry;
+					hint_femp.count = 1;
+				}
+			}
+
+			if (type == TYPE_UNUSED) {
+				brelse(bh);
+				goto not_found;
+			}
+
+			if (type != TYPE_VOLUME) {
+				brelse(bh);
+				continue;
+			}
+
+			memset(es, 0, sizeof(*es));
+			es->sb = sb;
+			es->bh = es->__bh;
+			es->bh[0] = bh;
+			es->num_bh = 1;
+			es->start_off = EXFAT_DEN_TO_B(i) % sb->s_blocksize;
+
+			return 0;
+		}
+
+		if (exfat_get_next_cluster(sb, &(clu.dir)))
+			return -EIO;
+	}
+
+not_found:
+	if (hint_femp.eidx == EXFAT_HINT_NONE) {
+		hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
+		hint_femp.eidx = dentry;
+		hint_femp.count = 0;
+	}
+
+	ei->hint_femp = hint_femp;
+
+	return -ENOENT;
+}
+
+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 exfat_entry_set_cache es;
+	struct exfat_dentry *ep;
+
+	mutex_lock(&sbi->s_lock);
+
+	memset(label_out, 0, sizeof(*label_out));
+	ret = exfat_get_volume_label_dentry(sb, &es);
+	if (ret < 0) {
+		/*
+		 * 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)
+			ret = 0;
+
+		goto unlock;
+	}
+
+	ep = exfat_get_dentry_cached(&es, 0);
+	label_out->name_len = ep->dentry.volume_label.char_count;
+	if (label_out->name_len > EXFAT_VOLUME_LABEL_LEN) {
+		ret = -EIO;
+		goto unlock;
+	}
+
+	for (i = 0; i < label_out->name_len; i++)
+		label_out->name[i] = le16_to_cpu(ep->dentry.volume_label.volume_label[i]);
+
+unlock:
+	mutex_unlock(&sbi->s_lock);
+	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 inode *root_inode = sb->s_root->d_inode;
+	struct exfat_entry_set_cache es;
+	struct exfat_chain clu;
+	struct exfat_dentry *ep;
+
+	if (label->name_len > EXFAT_VOLUME_LABEL_LEN)
+		return -EINVAL;
+
+	mutex_lock(&sbi->s_lock);
+
+	ret = exfat_get_volume_label_dentry(sb, &es);
+	if (ret == -ENOENT) {
+		if (label->name_len == 0) {
+			/* No volume label dentry, no need to clear */
+			ret = 0;
+			goto unlock;
+		}
+
+		ret = exfat_find_empty_entry(root_inode, &clu, 1, &es);
+	}
+
+	if (ret < 0)
+		goto unlock;
+
+	ep = exfat_get_dentry_cached(&es, 0);
+
+	if (label->name_len == 0 && ep->dentry.volume_label.char_count == 0) {
+		/* volume label had been cleared */
+		exfat_put_dentry_set(&es, 0);
+		goto unlock;
+	}
+
+	memset(ep, 0, sizeof(*ep));
+	ep->type = EXFAT_VOLUME;
+
+	for (i = 0; i < label->name_len; i++)
+		ep->dentry.volume_label.volume_label[i] =
+			cpu_to_le16(label->name[i]);
+
+	ep->dentry.volume_label.char_count = label->name_len;
+	es.modified = true;
+
+	ret = exfat_put_dentry_set(&es, IS_DIRSYNC(root_inode));
+
+unlock:
+	mutex_unlock(&sbi->s_lock);
+	return ret;
+}
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index f8ead4d47ef0..329697c89d09 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -477,6 +477,9 @@ 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);
@@ -517,6 +520,10 @@ int exfat_get_empty_dentry_set(struct exfat_entry_set_cache *es,
 		unsigned int num_entries);
 int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync);
 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
+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);
 
 /* inode.c */
 extern const struct inode_operations exfat_file_inode_operations;
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..f246cf439588 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -486,6 +486,54 @@ 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 label[FSLABEL_MAX] = {0};
+	struct exfat_uni_name uniname;
+
+	ret = exfat_read_volume_label(sb, &uniname);
+	if (ret < 0)
+		return ret;
+
+	ret = exfat_utf16_to_nls(sb, &uniname, label, uniname.name_len);
+	if (ret < 0)
+		return ret;
+
+	if (copy_to_user((char __user *)arg, label, ret + 1))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int exfat_ioctl_set_volume_label(struct super_block *sb,
+					unsigned long arg)
+{
+	int ret = 0, lossy;
+	char label[FSLABEL_MAX];
+	struct exfat_uni_name uniname;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(label, (char __user *)arg, FSLABEL_MAX))
+		return -EFAULT;
+
+	memset(&uniname, 0, sizeof(uniname));
+	if (label[0]) {
+		ret = exfat_nls_to_utf16(sb, label, FSLABEL_MAX,
+					 &uniname, &lossy);
+		if (ret < 0)
+			return ret;
+		else if (lossy & NLS_NAME_LOSSY)
+			return -EINVAL;
+	}
+
+	uniname.name_len = ret;
+
+	return exfat_write_volume_label(sb, &uniname);
+}
+
 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
@@ -500,6 +548,10 @@ 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)
 {
-- 
2.34.1

RE: [PATCH v7 1/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[Sungjong Seo]

> Add support for reading / writing to the exfat volume label from the
> FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls
> 
> Co-developed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
> Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
> Signed-off-by: Ethan Ferguson <ethan.ferguson@zetier.com>

Looks great! Thanks.
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>

> ---
>  fs/exfat/dir.c       | 158 +++++++++++++++++++++++++++++++++++++++++++
>  fs/exfat/exfat_fs.h  |   7 ++
>  fs/exfat/exfat_raw.h |   6 ++
>  fs/exfat/file.c      |  52 ++++++++++++++
>  fs/exfat/namei.c     |   2 +-
>  5 files changed, 224 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
> index ee060e26f51d..55d826f6475d 100644
> --- a/fs/exfat/dir.c
> +++ b/fs/exfat/dir.c
> @@ -1244,3 +1244,161 @@ int exfat_count_dir_entries(struct super_block
*sb,
> struct exfat_chain *p_dir)
> 
>  	return count;
>  }
> +
> +static int exfat_get_volume_label_dentry(struct super_block *sb,
> +		struct exfat_entry_set_cache *es)
> +{
> +	int i;
> +	int dentry = 0;
> +	unsigned int type;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_hint_femp hint_femp;
> +	struct exfat_inode_info *ei = EXFAT_I(sb->s_root->d_inode);
> +	struct exfat_chain clu;
> +	struct exfat_dentry *ep;
> +	struct buffer_head *bh;
> +
> +	hint_femp.eidx = EXFAT_HINT_NONE;
> +	exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
> +
> +	while (clu.dir != EXFAT_EOF_CLUSTER) {
> +		for (i = 0; i < sbi->dentries_per_clu; i++, dentry++) {
> +			ep = exfat_get_dentry(sb, &clu, i, &bh);
> +			if (!ep)
> +				return -EIO;
> +
> +			type = exfat_get_entry_type(ep);
> +			if (hint_femp.eidx == EXFAT_HINT_NONE) {
> +				if (type == TYPE_DELETED || type ==
TYPE_UNUSED)
> {
> +					hint_femp.cur = clu;
> +					hint_femp.eidx = dentry;
> +					hint_femp.count = 1;
> +				}
> +			}
> +
> +			if (type == TYPE_UNUSED) {
> +				brelse(bh);
> +				goto not_found;
> +			}
> +
> +			if (type != TYPE_VOLUME) {
> +				brelse(bh);
> +				continue;
> +			}
> +
> +			memset(es, 0, sizeof(*es));
> +			es->sb = sb;
> +			es->bh = es->__bh;
> +			es->bh[0] = bh;
> +			es->num_bh = 1;
> +			es->start_off = EXFAT_DEN_TO_B(i) % sb->s_blocksize;
> +
> +			return 0;
> +		}
> +
> +		if (exfat_get_next_cluster(sb, &(clu.dir)))
> +			return -EIO;
> +	}
> +
> +not_found:
> +	if (hint_femp.eidx == EXFAT_HINT_NONE) {
> +		hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
> +		hint_femp.eidx = dentry;
> +		hint_femp.count = 0;
> +	}
> +
> +	ei->hint_femp = hint_femp;
> +
> +	return -ENOENT;
> +}
> +
> +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 exfat_entry_set_cache es;
> +	struct exfat_dentry *ep;
> +
> +	mutex_lock(&sbi->s_lock);
> +
> +	memset(label_out, 0, sizeof(*label_out));
> +	ret = exfat_get_volume_label_dentry(sb, &es);
> +	if (ret < 0) {
> +		/*
> +		 * 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)
> +			ret = 0;
> +
> +		goto unlock;
> +	}
> +
> +	ep = exfat_get_dentry_cached(&es, 0);
> +	label_out->name_len = ep->dentry.volume_label.char_count;
> +	if (label_out->name_len > EXFAT_VOLUME_LABEL_LEN) {
> +		ret = -EIO;
> +		goto unlock;
> +	}
> +
> +	for (i = 0; i < label_out->name_len; i++)
> +		label_out->name[i] = le16_to_cpu(ep-
> >dentry.volume_label.volume_label[i]);
> +
> +unlock:
> +	mutex_unlock(&sbi->s_lock);
> +	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 inode *root_inode = sb->s_root->d_inode;
> +	struct exfat_entry_set_cache es;
> +	struct exfat_chain clu;
> +	struct exfat_dentry *ep;
> +
> +	if (label->name_len > EXFAT_VOLUME_LABEL_LEN)
> +		return -EINVAL;
> +
> +	mutex_lock(&sbi->s_lock);
> +
> +	ret = exfat_get_volume_label_dentry(sb, &es);
> +	if (ret == -ENOENT) {
> +		if (label->name_len == 0) {
> +			/* No volume label dentry, no need to clear */
> +			ret = 0;
> +			goto unlock;
> +		}
> +
> +		ret = exfat_find_empty_entry(root_inode, &clu, 1, &es);
> +	}
> +
> +	if (ret < 0)
> +		goto unlock;
> +
> +	ep = exfat_get_dentry_cached(&es, 0);
> +
> +	if (label->name_len == 0 && ep->dentry.volume_label.char_count == 0)
> {
> +		/* volume label had been cleared */
> +		exfat_put_dentry_set(&es, 0);
> +		goto unlock;
> +	}
> +
> +	memset(ep, 0, sizeof(*ep));
> +	ep->type = EXFAT_VOLUME;
> +
> +	for (i = 0; i < label->name_len; i++)
> +		ep->dentry.volume_label.volume_label[i] =
> +			cpu_to_le16(label->name[i]);
> +
> +	ep->dentry.volume_label.char_count = label->name_len;
> +	es.modified = true;
> +
> +	ret = exfat_put_dentry_set(&es, IS_DIRSYNC(root_inode));
> +
> +unlock:
> +	mutex_unlock(&sbi->s_lock);
> +	return ret;
> +}
> diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
> index f8ead4d47ef0..329697c89d09 100644
> --- a/fs/exfat/exfat_fs.h
> +++ b/fs/exfat/exfat_fs.h
> @@ -477,6 +477,9 @@ 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);
> @@ -517,6 +520,10 @@ int exfat_get_empty_dentry_set(struct
> exfat_entry_set_cache *es,
>  		unsigned int num_entries);
>  int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync);
>  int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain
> *p_dir);
> +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);
> 
>  /* inode.c */
>  extern const struct inode_operations exfat_file_inode_operations;
> 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..f246cf439588 100644
> --- a/fs/exfat/file.c
> +++ b/fs/exfat/file.c
> @@ -486,6 +486,54 @@ 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 label[FSLABEL_MAX] = {0};
> +	struct exfat_uni_name uniname;
> +
> +	ret = exfat_read_volume_label(sb, &uniname);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = exfat_utf16_to_nls(sb, &uniname, label, uniname.name_len);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (copy_to_user((char __user *)arg, label, ret + 1))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
> +static int exfat_ioctl_set_volume_label(struct super_block *sb,
> +					unsigned long arg)
> +{
> +	int ret = 0, lossy;
> +	char label[FSLABEL_MAX];
> +	struct exfat_uni_name uniname;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +
> +	if (copy_from_user(label, (char __user *)arg, FSLABEL_MAX))
> +		return -EFAULT;
> +
> +	memset(&uniname, 0, sizeof(uniname));
> +	if (label[0]) {
> +		ret = exfat_nls_to_utf16(sb, label, FSLABEL_MAX,
> +					 &uniname, &lossy);
> +		if (ret < 0)
> +			return ret;
> +		else if (lossy & NLS_NAME_LOSSY)
> +			return -EINVAL;
> +	}
> +
> +	uniname.name_len = ret;
> +
> +	return exfat_write_volume_label(sb, &uniname);
> +}
> +
>  long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  {
>  	struct inode *inode = file_inode(filp);
> @@ -500,6 +548,10 @@ 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)
>  {
> --
> 2.34.1

Re: [PATCH v7 1/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[Namjae Jeon]

On Fri, Sep 12, 2025 at 12:26 PM Ethan Ferguson
<ethan.ferguson@zetier.com> wrote:
>
> Add support for reading / writing to the exfat volume label from the
> FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls
>
> Co-developed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
> Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
> Signed-off-by: Ethan Ferguson <ethan.ferguson@zetier.com>
Applied it to #dev.
Thanks!

Re: [PATCH v7 1/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[Yuezhang.Mo]

On Fri, Sep 12, 2025 11:26 Ethan Ferguson <ethan.ferguson@zetier.com> wrote:
> +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 exfat_entry_set_cache es;
> +       struct exfat_dentry *ep;
> +
> +       mutex_lock(&sbi->s_lock);
> +
> +       memset(label_out, 0, sizeof(*label_out));
> +       ret = exfat_get_volume_label_dentry(sb, &es);
> +       if (ret < 0) {
> +               /*
> +                * 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)
> +                       ret = 0;
> +
> +               goto unlock;
> +       }
> +
> +       ep = exfat_get_dentry_cached(&es, 0);
> +       label_out->name_len = ep->dentry.volume_label.char_count;
> +       if (label_out->name_len > EXFAT_VOLUME_LABEL_LEN) {
> +               ret = -EIO;
> +               goto unlock;
> +       }
> +
> +       for (i = 0; i < label_out->name_len; i++)
> +               label_out->name[i] = le16_to_cpu(ep->dentry.volume_label.volume_label[i]);
> +
> +unlock:
> +       mutex_unlock(&sbi->s_lock);
> +       return ret;
> +}

Hi Ethan Ferguson,

This function has a buffer leak due to a missed call to
exfat_put_dentry_set(). Please fix it.

Thanks

Re: [PATCH v7 1/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[Ethan Ferguson]

Hi,

On 9/28/25 06:28, Yuezhang.Mo@sony.com wrote:
> On Fri, Sep 12, 2025 11:26 Ethan Ferguson <ethan.ferguson@zetier.com> wrote:
>> +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 exfat_entry_set_cache es;
>> +       struct exfat_dentry *ep;
>> +
>> +       mutex_lock(&sbi->s_lock);
>> +
>> +       memset(label_out, 0, sizeof(*label_out));
>> +       ret = exfat_get_volume_label_dentry(sb, &es);
>> +       if (ret < 0) {
>> +               /*
>> +                * 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)
>> +                       ret = 0;
>> +
>> +               goto unlock;
>> +       }
>> +
>> +       ep = exfat_get_dentry_cached(&es, 0);
>> +       label_out->name_len = ep->dentry.volume_label.char_count;
>> +       if (label_out->name_len > EXFAT_VOLUME_LABEL_LEN) {
>> +               ret = -EIO;
>> +               goto unlock;
>> +       }
>> +
>> +       for (i = 0; i < label_out->name_len; i++)
>> +               label_out->name[i] = le16_to_cpu(ep->dentry.volume_label.volume_label[i]);
>> +
>> +unlock:
>> +       mutex_unlock(&sbi->s_lock);
>> +       return ret;
>> +}
> 
> Hi Ethan Ferguson,
> 
> This function has a buffer leak due to a missed call to
> exfat_put_dentry_set(). Please fix it.
> 
> Thanks
Apologies that I missed that, I would be more than happy to submit a fixed patch for this,
but I checked the dev branch of the exfat tree and noticed some lines were added to fix this
problem in my commit. If true, this is fine by me, and I will sign off on it, but I just
want to make sure that's true, because if so then I don't think another patch by me is needed.

Thank you!

Re: [PATCH v7 1/1] exfat: Add support for FS_IOC_{GET,SET}FSLABEL

[Namjae Jeon]

On Thu, Oct 2, 2025 at 1:34 AM Ethan Ferguson <ethan.ferguson@zetier.com> wrote:
>
> Hi,
>
> On 9/28/25 06:28, Yuezhang.Mo@sony.com wrote:
> > On Fri, Sep 12, 2025 11:26 Ethan Ferguson <ethan.ferguson@zetier.com> wrote:
> >> +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 exfat_entry_set_cache es;
> >> +       struct exfat_dentry *ep;
> >> +
> >> +       mutex_lock(&sbi->s_lock);
> >> +
> >> +       memset(label_out, 0, sizeof(*label_out));
> >> +       ret = exfat_get_volume_label_dentry(sb, &es);
> >> +       if (ret < 0) {
> >> +               /*
> >> +                * 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)
> >> +                       ret = 0;
> >> +
> >> +               goto unlock;
> >> +       }
> >> +
> >> +       ep = exfat_get_dentry_cached(&es, 0);
> >> +       label_out->name_len = ep->dentry.volume_label.char_count;
> >> +       if (label_out->name_len > EXFAT_VOLUME_LABEL_LEN) {
> >> +               ret = -EIO;
> >> +               goto unlock;
> >> +       }
> >> +
> >> +       for (i = 0; i < label_out->name_len; i++)
> >> +               label_out->name[i] = le16_to_cpu(ep->dentry.volume_label.volume_label[i]);
> >> +
> >> +unlock:
> >> +       mutex_unlock(&sbi->s_lock);
> >> +       return ret;
> >> +}
> >
> > Hi Ethan Ferguson,
> >
> > This function has a buffer leak due to a missed call to
> > exfat_put_dentry_set(). Please fix it.
> >
> > Thanks
> Apologies that I missed that, I would be more than happy to submit a fixed patch for this,
> but I checked the dev branch of the exfat tree and noticed some lines were added to fix this
> problem in my commit. If true, this is fine by me, and I will sign off on it, but I just
> want to make sure that's true, because if so then I don't think another patch by me is needed.
I have directly updated it. So you don't need to submit the updated
patch to the list.
Thanks.
>
> Thank you!