Re: [PATCH v2 2/2] staging: erofs: complete POSIX ACL support

[Dan Carpenter]

On Sat, Jan 26, 2019 at 10:48:53AM +0800, Chao Yu wrote:
> On 2019/1/26 0:10, Gao Xiang wrote:
> > Let's add .get_acl() to read the file's acl from its xattrs
> > to make POSIX ACL usable.
> > 
> > Here is the on-disk detail,
> > fullname: system.posix_acl_access
> > struct erofs_xattr_entry:
> >         .e_name_len = 0
> >         .e_name_index = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS (2)
> > 
> > fullname: system.posix_acl_default
> > struct erofs_xattr_entry:
> > 	.e_name_len = 0
> > 	.e_name_index = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT (3)
> > 
> > Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx>
> > ---
> > change log v2:
> >  - add the missing SB_POSIXACL flag;
> >  - fix the on-disk detail, use .e_name_len == 0 and proper prefix value;
> >  - tested ok with xattr enabled erofs_mkfs;
> 
> >  .../erofs/Documentation/filesystems/erofs.txt      |  2 ++
> >  drivers/staging/erofs/inode.c                      |  3 ++
> >  drivers/staging/erofs/namei.c                      |  1 +
> >  drivers/staging/erofs/super.c                      |  8 +++++
> >  drivers/staging/erofs/xattr.c                      | 37 ++++++++++++++++++++++
> >  drivers/staging/erofs/xattr.h                      |  6 ++++
> >  6 files changed, 57 insertions(+)
> > 
> > diff --git a/drivers/staging/erofs/Documentation/filesystems/erofs.txt b/drivers/staging/erofs/Documentation/filesystems/erofs.txt
> > index 803988d74c21..961ec4da7705 100644
> > --- a/drivers/staging/erofs/Documentation/filesystems/erofs.txt
> > +++ b/drivers/staging/erofs/Documentation/filesystems/erofs.txt
> > @@ -36,6 +36,8 @@ Here is the main features of EROFS:
> >  
> >   - Support xattr inline and tail-end data inline for all files;
> >  
> > + - Support POSIX.1e ACLs by using xattrs;
> > +
> >   - Support transparent file compression as an option:
> >     LZ4 algorithm with 4 KB fixed-output compression for high performance;
> >  
> > diff --git a/drivers/staging/erofs/inode.c b/drivers/staging/erofs/inode.c
> > index 4f04f7c38cf2..924b8dfc7a8f 100644
> > --- a/drivers/staging/erofs/inode.c
> > +++ b/drivers/staging/erofs/inode.c
> > @@ -287,6 +287,7 @@ const struct inode_operations erofs_generic_iops = {
> >  #ifdef CONFIG_EROFS_FS_XATTR
> >  	.listxattr = erofs_listxattr,
> >  #endif
> > +	.get_acl = erofs_get_acl,
> >  };
> >  
> >  const struct inode_operations erofs_symlink_iops = {
> > @@ -294,6 +295,7 @@ const struct inode_operations erofs_symlink_iops = {
> >  #ifdef CONFIG_EROFS_FS_XATTR
> >  	.listxattr = erofs_listxattr,
> >  #endif
> > +	.get_acl = erofs_get_acl,
> >  };
> >  
> >  const struct inode_operations erofs_fast_symlink_iops = {
> > @@ -301,5 +303,6 @@ const struct inode_operations erofs_fast_symlink_iops = {
> >  #ifdef CONFIG_EROFS_FS_XATTR
> >  	.listxattr = erofs_listxattr,
> >  #endif
> > +	.get_acl = erofs_get_acl,
> >  };
> >  
> > diff --git a/drivers/staging/erofs/namei.c b/drivers/staging/erofs/namei.c
> > index 7fed1f996ab0..b1752adc5934 100644
> > --- a/drivers/staging/erofs/namei.c
> > +++ b/drivers/staging/erofs/namei.c
> > @@ -238,5 +238,6 @@ const struct inode_operations erofs_dir_iops = {
> >  #ifdef CONFIG_EROFS_FS_XATTR
> >  	.listxattr = erofs_listxattr,
> >  #endif
> > +	.get_acl = erofs_get_acl,
> >  };
> >  
> > diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
> > index 176fca2af379..54cd7dac0a1f 100644
> > --- a/drivers/staging/erofs/super.c
> > +++ b/drivers/staging/erofs/super.c
> > @@ -398,6 +398,14 @@ static int erofs_read_super(struct super_block *sb,
> >  	if (!silent)
> >  		infoln("root inode @ nid %llu", ROOT_NID(sbi));
> >  
> > +#ifdef CONFIG_EROFS_FS_POSIX_ACL
> > +	/* Update the POSIXACL Flag */
> > +	if (test_opt(sbi, POSIX_ACL))
> > +		sb->s_flags |= SB_POSIXACL;
> > +	else
> > +		sb->s_flags &= ~SB_POSIXACL;
> > +#endif
> > +
> >  #ifdef CONFIG_EROFS_FS_ZIP
> >  	INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC);
> >  #endif
> > diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
> > index 7de46690d972..6759485ae862 100644
> > --- a/drivers/staging/erofs/xattr.c
> > +++ b/drivers/staging/erofs/xattr.c
> > @@ -643,3 +643,40 @@ ssize_t erofs_listxattr(struct dentry *dentry,
> >  	return shared_listxattr(&it);
> >  }
> >  
> > +#ifdef CONFIG_EROFS_FS_POSIX_ACL
> > +struct posix_acl *erofs_get_acl(struct inode *inode, int type)
> > +{
> > +	struct posix_acl *acl;
> > +	int ea_prefix, rc;
> > +	char *value = NULL;
> > +
> > +	switch(type) {
> > +	case ACL_TYPE_ACCESS:
> > +		ea_prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
> > +		break;
> > +	case ACL_TYPE_DEFAULT:
> > +		ea_prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
> > +		break;
> > +	default:
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +
> > +	rc = erofs_getxattr(inode, ea_prefix, "", NULL, 0);
> > +	if (rc > 0) {
> > +		value = kvmalloc(rc, GFP_KERNEL);
> 
> erofs_kmalloc() is enough?
> 
> Thanks,
> 

Hopefully, regular kmalloc() is enough.

Do really need the erofs_kmalloc() function?  Regular kmalloc() has
fault injection already.  Have you tried to use it?

regards,
dan carpenter