fs: add get_acl helper

Christoph Hellwig · Al Viro · commit 2982baa2ae31 · 2014-01-25T23:58:16.000-05:00
Factor out the code to get an ACL either from the inode or disk from
check_acl, so that it can be used elsewhere later on.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
diff --git a/fs/namei.c b/fs/namei.c
@@ -235,27 +235,9 @@ static int check_acl(struct inode *inode, int mask)
 	        return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
 	}
 
-	acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
-
-	/*
-	 * A filesystem can force a ACL callback by just never filling the
-	 * ACL cache. But normally you'd fill the cache either at inode
-	 * instantiation time, or on the first ->get_acl call.
-	 *
-	 * If the filesystem doesn't have a get_acl() function at all, we'll
-	 * just create the negative cache entry.
-	 */
-	if (acl == ACL_NOT_CACHED) {
-	        if (inode->i_op->get_acl) {
-			acl = inode->i_op->get_acl(inode, ACL_TYPE_ACCESS);
-			if (IS_ERR(acl))
-				return PTR_ERR(acl);
-		} else {
-		        set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
-		        return -EAGAIN;
-		}
-	}
-
+	acl = get_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
 	if (acl) {
 	        int error = posix_acl_permission(inode, acl, mask);
 	        posix_acl_release(acl);
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
@@ -26,6 +26,33 @@ EXPORT_SYMBOL(posix_acl_valid);
 EXPORT_SYMBOL(posix_acl_equiv_mode);
 EXPORT_SYMBOL(posix_acl_from_mode);
 
+struct posix_acl *get_acl(struct inode *inode, int type)
+{
+	struct posix_acl *acl;
+
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
+	if (!IS_POSIXACL(inode))
+		return NULL;
+
+	/*
+	 * A filesystem can force a ACL callback by just never filling the
+	 * ACL cache. But normally you'd fill the cache either at inode
+	 * instantiation time, or on the first ->get_acl call.
+	 *
+	 * If the filesystem doesn't have a get_acl() function at all, we'll
+	 * just create the negative cache entry.
+	 */
+	if (!inode->i_op->get_acl) {
+		set_cached_acl(inode, type, NULL);
+		return NULL;
+	}
+	return inode->i_op->get_acl(inode, type);
+}
+EXPORT_SYMBOL(get_acl);
+
 /*
  * Init a fresh posix_acl
  */
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
@@ -175,4 +175,6 @@ static inline void cache_no_acl(struct inode *inode)
 #endif
 }
 
+struct posix_acl *get_acl(struct inode *inode, int type);
+
 #endif  /* __LINUX_POSIX_ACL_H */

Original file line number	Diff line number	Diff line change
`@@ -175,4 +175,6 @@ static inline void cache_no_acl(struct inode *inode)`
`175`	`175`	`#endif`
`176`	`176`	`}`
`177`	`177`
	`178`	`+struct posix_acl get_acl(struct inode inode, int type);`
	`179`	`+`
`178`	`180`	`#endif /* __LINUX_POSIX_ACL_H */`