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[PATCH 05/21] fs: add generic xattr_acl handlers

To: viro@xxxxxxxxxxxxxxxxxx
Subject: [PATCH 05/21] fs: add generic xattr_acl handlers
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Fri, 20 Dec 2013 05:16:40 -0800
Cc: linux-fsdevel@xxxxxxxxxxxxxxx, linux-btrfs@xxxxxxxxxxxxxxx, linux-ext4@xxxxxxxxxxxxxxx, linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx, linux-mtd@xxxxxxxxxxxxxxxxxxx, Mark Fasheh <mfasheh@xxxxxxxx>, Joel Becker <jlbec@xxxxxxxxxxxx>, reiserfs-devel@xxxxxxxxxxxxxxx, xfs@xxxxxxxxxxx, jfs-discussion@xxxxxxxxxxxxxxxxxxxxx, cluster-devel@xxxxxxxxxx, linux-nfs@xxxxxxxxxxxxxxx, Andreas Gruenbacher <andreas.gruenbacher@xxxxxxxxxx>, Jan Kara <jack@xxxxxxx>
Delivered-to: xfs@xxxxxxxxxxx
References: <20131220131635.650823732@xxxxxxxxxxxxxxxxxxxxxx>
User-agent: quilt/0.60-1
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@xxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
---
 fs/posix_acl.c                  |  102 +++++++++++++++++++++++++++++++++++++++
 include/linux/posix_acl_xattr.h |    3 ++
 2 files changed, 105 insertions(+)

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index e329c21..3c0f659 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -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>
 
@@ -610,3 +611,104 @@ 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);
diff --git a/include/linux/posix_acl_xattr.h b/include/linux/posix_acl_xattr.h
index ad93ad0..6f14ee2 100644
--- a/include/linux/posix_acl_xattr.h
+++ b/include/linux/posix_acl_xattr.h
@@ -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 */
-- 
1.7.10.4


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