On 9/22/25 17:29, Bo Liu wrote:
> From: Bo Liu (OpenAnolis) <[email protected]>
>
> Add support for reading to the erofs volume label from the
> FS_IOC_GETFSLABEL ioctls.
>
> Signed-off-by: Bo Liu (OpenAnolis) <[email protected]>
> ---
>
> v1:
> https://lore.kernel.org/linux-erofs/[email protected]/
> v2:
> https://lore.kernel.org/linux-erofs/[email protected]/
> v3:
> https://lore.kernel.org/linux-erofs/[email protected]/
>
> change since v3:
> - move functions into inode.
> - remove useless comment.
>
> fs/erofs/data.c | 4 ++++
> fs/erofs/dir.c | 4 ++++
> fs/erofs/inode.c | 40 ++++++++++++++++++++++++++++++++++++----
> fs/erofs/internal.h | 6 ++++++
> fs/erofs/super.c | 8 ++++++++
> 5 files changed, 58 insertions(+), 4 deletions(-)
>
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index 3b1ba571c728..8ca29962a3dd 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -475,6 +475,10 @@ static loff_t erofs_file_llseek(struct file *file,
> loff_t offset, int whence)
> const struct file_operations erofs_file_fops = {
> .llseek = erofs_file_llseek,
> .read_iter = erofs_file_read_iter,
> + .unlocked_ioctl = erofs_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = erofs_compat_ioctl,
> +#endif
> .mmap_prepare = erofs_file_mmap_prepare,
> .get_unmapped_area = thp_get_unmapped_area,
> .splice_read = filemap_splice_read,
> diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
> index debf469ad6bd..32b4f5aa60c9 100644
> --- a/fs/erofs/dir.c
> +++ b/fs/erofs/dir.c
> @@ -123,4 +123,8 @@ const struct file_operations erofs_dir_fops = {
> .llseek = generic_file_llseek,
> .read = generic_read_dir,
> .iterate_shared = erofs_readdir,
> + .unlocked_ioctl = erofs_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = erofs_compat_ioctl,
> +#endif
> };
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index 9a2f59721522..7a9a9081f890 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -213,10 +213,7 @@ static int erofs_fill_inode(struct inode *inode)
> switch (inode->i_mode & S_IFMT) {
> case S_IFREG:
> inode->i_op = &erofs_generic_iops;
> - if (erofs_inode_is_data_compressed(vi->datalayout))
> - inode->i_fop = &generic_ro_fops;
> - else
> - inode->i_fop = &erofs_file_fops;
> + inode->i_fop = &erofs_file_fops;
> break;
> case S_IFDIR:
> inode->i_op = &erofs_dir_iops;
> @@ -341,6 +338,41 @@ int erofs_getattr(struct mnt_idmap *idmap, const struct
> path *path,
> return 0;
> }
>
> +static int erofs_ioctl_get_volume_label(struct inode *inode, void __user
> *arg)
> +{
> + struct erofs_sb_info *sbi = EROFS_I_SB(inode);
> + int ret;
> +
> + if (!sbi->volume_name)
> + ret = clear_user(arg, 1);
> + else
> + ret = copy_to_user(arg, sbi->volume_name,
> + strlen(sbi->volume_name));
> +
> + return ret ? -EFAULT : 0;
> +}
> +
> +long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> +{
> + struct inode *inode = file_inode(filp);
> + void __user *argp = (void __user *)arg;
> +
> + switch (cmd) {
> + case FS_IOC_GETFSLABEL:
> + return erofs_ioctl_get_volume_label(inode, argp);
> + default:
> + return -ENOTTY;
> + }
> +}
> +
> +#ifdef CONFIG_COMPAT
> +long erofs_compat_ioctl(struct file *filp, unsigned int cmd,
> + unsigned long arg)
> +{
> + return erofs_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
> +}
> +#endif
> +
> const struct inode_operations erofs_generic_iops = {
> .getattr = erofs_getattr,
> .listxattr = erofs_listxattr,
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 4ccc5f0ee8df..b70902e00586 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -166,6 +166,8 @@ struct erofs_sb_info {
> struct erofs_domain *domain;
> char *fsid;
> char *domain_id;
> +
> + char *volume_name;
> };
>
> #define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
> @@ -535,6 +537,10 @@ static inline struct bio *erofs_fscache_bio_alloc(struct
> erofs_map_dev *mdev) {
> static inline void erofs_fscache_submit_bio(struct bio *bio) {}
> #endif
>
> +long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
#ifdef CONFIG_COMPAT
> +long erofs_compat_ioctl(struct file *filp, unsigned int cmd,
> + unsigned long arg);
#endif
Thanks,
> +
> #define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
>
> #endif /* __EROFS_INTERNAL_H */
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 1b529ace4db0..f1535ebe03ec 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -343,6 +343,13 @@ static int erofs_read_superblock(struct super_block *sb)
> sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
> super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
>
> + if (dsb->volume_name[0]) {
> + sbi->volume_name = kstrndup(dsb->volume_name,
> + sizeof(dsb->volume_name),
> GFP_KERNEL);
> + if (!sbi->volume_name)
> + return -ENOMEM;
> + }
> +
> /* parse on-disk compression configurations */
> ret = z_erofs_parse_cfgs(sb, dsb);
> if (ret < 0)
> @@ -822,6 +829,7 @@ static void erofs_sb_free(struct erofs_sb_info *sbi)
> kfree(sbi->domain_id);
> if (sbi->dif0.file)
> fput(sbi->dif0.file);
> + kfree(sbi->volume_name);
> kfree(sbi);
> }
>
