fs: add get_acl helper

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 <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 32 insertions, 21 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 3531deebad30..bcb838e2e52f 100644
--- 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
index 359d70b0e947..30524de49a6b 100644
--- 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
index 7931efe71175..a8d9918c0b20 100644
--- 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 */