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fs: add generic xattr_acl handlers

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With the ->set_acl inode operation we can implement the Posix ACL
xattr handlers in generic code instead of duplicating them all
over the tree.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2013-12-20 05:16:40 -08:00 • committed by Al Viro
commit 2aeccbe957
2 changed files with 105 additions and 0 deletions
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102
fs/posix_acl.c
View file

@ -17,6 +17,7 @@
#include <linux/sched.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/export.h>
#include <linux/user_namespace.h>
@ -611,3 +612,104 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
return real_size;
}
EXPORT_SYMBOL (posix_acl_to_xattr);
static int
posix_acl_xattr_get(struct dentry *dentry, const char *name,
void *value, size_t size, int type)
{
struct posix_acl *acl;
int error;
if (!IS_POSIXACL(dentry->d_inode))
return -EOPNOTSUPP;
if (S_ISLNK(dentry->d_inode->i_mode))
return -EOPNOTSUPP;
acl = get_acl(dentry->d_inode, type);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl == NULL)
return -ENODATA;
error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
posix_acl_release(acl);
return error;
}
static int
posix_acl_xattr_set(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags, int type)
{
struct inode *inode = dentry->d_inode;
struct posix_acl *acl = NULL;
int ret;
if (!IS_POSIXACL(inode))
return -EOPNOTSUPP;
if (!inode->i_op->set_acl)
return -EOPNOTSUPP;
if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
return value ? -EACCES : 0;
if (!inode_owner_or_capable(inode))
return -EPERM;
if (value) {
acl = posix_acl_from_xattr(&init_user_ns, value, size);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
ret = posix_acl_valid(acl);
if (ret)
goto out;
}
}
ret = inode->i_op->set_acl(inode, acl, type);
out:
posix_acl_release(acl);
return ret;
}
static size_t
posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size,
const char *name, size_t name_len, int type)
{
const char *xname;
size_t size;
if (!IS_POSIXACL(dentry->d_inode))
return -EOPNOTSUPP;
if (S_ISLNK(dentry->d_inode->i_mode))
return -EOPNOTSUPP;
if (type == ACL_TYPE_ACCESS)
xname = POSIX_ACL_XATTR_ACCESS;
else
xname = POSIX_ACL_XATTR_DEFAULT;
size = strlen(xname) + 1;
if (list && size <= list_size)
memcpy(list, xname, size);
return size;
}
const struct xattr_handler posix_acl_access_xattr_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.flags = ACL_TYPE_ACCESS,
.list = posix_acl_xattr_list,
.get = posix_acl_xattr_get,
.set = posix_acl_xattr_set,
};
EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
const struct xattr_handler posix_acl_default_xattr_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.list = posix_acl_xattr_list,
.get = posix_acl_xattr_get,
.set = posix_acl_xattr_set,
};
EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);

3
include/linux/posix_acl_xattr.h
View file

@ -69,4 +69,7 @@ struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
int posix_acl_to_xattr(struct user_namespace *user_ns,
const struct posix_acl *acl, void *buffer, size_t size);
extern const struct xattr_handler posix_acl_access_xattr_handler;
extern const struct xattr_handler posix_acl_default_xattr_handler;
#endif /* _POSIX_ACL_XATTR_H */