Turn do_link spaghetty into a normal loop

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 38 insertions, 45 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 675a712137f1..08da937b1ee2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1844,17 +1844,38 @@ reval:
         if (open_flag & O_EXCL)
                 nd.flags |= LOOKUP_EXCL;
         filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
-        if (!filp)
-                goto do_link;
-        goto out;
-
-exit_dput:
-        path_put_conditional(&path, &nd);
-        if (!IS_ERR(nd.intent.open.file))
-                release_open_intent(&nd);
-exit_parent:
-        path_put(&nd.path);
-        filp = ERR_PTR(error);
+        while (unlikely(!filp)) { /* trailing symlink */
+                error = -ELOOP;
+                if ((open_flag & O_NOFOLLOW) || count++ == 32)
+                        goto exit_dput;
+                /*
+                 * This is subtle. Instead of calling do_follow_link() we do
+                 * the thing by hands. The reason is that this way we have zero
+                 * link_count and path_walk() (called from ->follow_link)
+                 * honoring LOOKUP_PARENT.  After that we have the parent and
+                 * last component, i.e. we are in the same situation as after
+                 * the first path_walk().  Well, almost - if the last component
+                 * is normal we get its copy stored in nd->last.name and we will
+                 * have to putname() it when we are done. Procfs-like symlinks
+                 * just set LAST_BIND.
+                 */
+                nd.flags |= LOOKUP_PARENT;
+                error = security_inode_follow_link(path.dentry, &nd);
+                if (error)
+                        goto exit_dput;
+                error = __do_follow_link(&path, &nd);
+                path_put(&path);
+                if (error) {
+                        /* nd.path had been dropped */
+                        release_open_intent(&nd);
+                        filp = ERR_PTR(error);
+                        goto out;
+                }
+                nd.flags &= ~LOOKUP_PARENT;
+                filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
+                if (nd.last_type == LAST_NORM)
+                        __putname(nd.last.name);
+        }
 out:
         if (nd.root.mnt)
                 path_put(&nd.root);
@@ -1864,41 +1885,13 @@ out:
         }
         return filp;
 
-do_link:
-        error = -ELOOP;
-        if ((open_flag & O_NOFOLLOW) || count++ == 32)
-                goto exit_dput;
-        /*
-         * This is subtle. Instead of calling do_follow_link() we do the
-         * thing by hands. The reason is that this way we have zero link_count
-         * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
-         * After that we have the parent and last component, i.e.
-         * we are in the same situation as after the first path_walk().
-         * Well, almost - if the last component is normal we get its copy
-         * stored in nd->last.name and we will have to putname() it when we
-         * are done. Procfs-like symlinks just set LAST_BIND.
-         */
-        nd.flags |= LOOKUP_PARENT;
-        error = security_inode_follow_link(path.dentry, &nd);
-        if (error)
-                goto exit_dput;
-        error = __do_follow_link(&path, &nd);
-        path_put(&path);
-        if (error) {
-                /* Does someone understand code flow here? Or it is only
-                 * me so stupid? Anathema to whoever designed this non-sense
-                 * with "intent.open".
-                 */
+exit_dput:
+        path_put_conditional(&path, &nd);
+        if (!IS_ERR(nd.intent.open.file))
                 release_open_intent(&nd);
-                filp = ERR_PTR(error);
-                goto out;
-        }
-        nd.flags &= ~LOOKUP_PARENT;
-        filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
-        if (nd.last_type == LAST_NORM)
-                __putname(nd.last.name);
-        if (!filp)
-                goto do_link;
+exit_parent:
+        path_put(&nd.path);
+        filp = ERR_PTR(error);
         goto out;
 }