[PATCH 08/11] erofs: support special inode

[Gao Xiang]

Hi Guifu and Chao,

On 2018/6/22 10:01, Chao Yu wrote:
> This patch adds to support special inode, such as block dev, char,
> socket, pipe inode.
> 

To Guifu,

Could you test this patch based on your latest _erofs_mkfs_ which supports special inodes?
--- either for device files, named pipe files or socket files.

If this patch works fine, could you also reply with a "Tested-by:" tag?

> Signed-off-by: Chao Yu <yuchao0 at huawei.com>
> ---
>  fs/erofs/inode.c    | 33 +++++++++++++++++++++++++++++++--
>  fs/erofs/internal.h |  1 +
>  2 files changed, 32 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index 94e827b57a5b..3dbce0cf41ff 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -30,8 +30,16 @@ static int read_inode(struct inode *inode, void *data)
>  		vi->inode_isize = sizeof(struct erofs_inode_v2);
>  		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
>  
> -		vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
>  		inode->i_mode = le16_to_cpu(v2->i_mode);
> +		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
> +						S_ISLNK(inode->i_mode)) {
> +			vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
> +		} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
> +			inode->i_rdev =
> +				new_decode_dev(le32_to_cpu(v2->i_u.rdev));
> +		} else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
> +			inode->i_rdev = 0;
> +		}
To Chao,

It seems a default case missing here, and an error handling could be also added...

How about returning -EIO and furthermore
BUG_ON if CONFIG_EROFS_FS_DEBUG is enabled as well ?
(for commercial integrated test, it is hard to detect those error if just -EIO is returned.)

 18 config EROFS_FS_DEBUG
 19         bool "EROFS debugging feature"
 20         depends on EROFS_FS
 21         help
 22           Print erofs debugging messages and enable more BUG_ONs
 23           which check the filesystem consistency aggressively.
 24
 25           For daily use, say N.

So will the rest error handling code, I think.
How do you think?
If you also agree with that, let's add them gradually in the future.

>  
>  		i_uid_write(inode, le32_to_cpu(v2->i_uid));
>  		i_gid_write(inode, le32_to_cpu(v2->i_gid));
> @@ -50,8 +58,16 @@ static int read_inode(struct inode *inode, void *data)
>  		vi->inode_isize = sizeof(struct erofs_inode_v1);
>  		vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount);
>  
> -		vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
>  		inode->i_mode = le16_to_cpu(v1->i_mode);
> +		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
> +						S_ISLNK(inode->i_mode)) {
> +			vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
> +		} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
> +			inode->i_rdev =
> +				new_decode_dev(le32_to_cpu(v1->i_u.rdev));
> +		} else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
> +			inode->i_rdev = 0;
> +		}

ditto,


The other code looks fine for me,
I think a basic test is needed for the function of this patch tho.

If you send out the next patch, you could add:
Reviewed-by: Gao Xiang <gaoxiang25 at huawei.com>

Thanks,
Gao Xiang

>  
>  		i_uid_write(inode, le16_to_cpu(v1->i_uid));
>  		i_gid_write(inode, le16_to_cpu(v1->i_gid));
> @@ -168,6 +184,12 @@ int fill_inode(struct inode *inode, int isdir)
>  				&page_symlink_inode_operations;
>  #endif
>  			inode_nohighmem(inode);
> +		} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
> +			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
> +#ifdef CONFIG_EROFS_FS_XATTR
> +			inode->i_op = &erofs_special_inode_operations;
> +#endif
> +			init_special_inode(inode, inode->i_mode, inode->i_rdev);
>  		} else {
>  			err = -EIO;
>  			goto out_unlock;
> @@ -244,6 +266,13 @@ const struct inode_operations erofs_symlink_xattr_iops = {
>  	.listxattr = erofs_listxattr,
>  #endif
>  };
> +
> +const struct inode_operations erofs_special_inode_operations = {
> +#if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 9, 0))
> +		.listxattr = erofs_listxattr,
> +#endif
> +};
> +
>  #endif
>  
>  #if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0))
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 7670c2ed53d2..43620c07044d 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -364,6 +364,7 @@ extern const struct inode_operations simple_symlink_inode_operations;
>  #ifdef CONFIG_EROFS_FS_XATTR
>  extern const struct inode_operations erofs_symlink_xattr_iops;
>  extern const struct inode_operations erofs_fast_symlink_xattr_iops;
> +extern const struct inode_operations erofs_special_inode_operations;
>  #endif
>  
>  static inline void set_inode_fast_symlink(struct inode *inode)
>