separate -ESTALE/-ECHILD retries in do_filp_open() from real work

new helper: path_openat().  Does what do_filp_open() does, except
that it tries only the walk mode (RCU/normal/force revalidation)
it had been told to.

Both create and non-create branches are using path_lookupat() now.
Fixed the double audit_inode() in non-create branch.

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

diff --git a/fs/namei.c b/fs/namei.c
index 9c7fa94..01a17dd 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2292,19 +2292,14 @@ exit:
        return ERR_PTR(error);
 }
 
-/*
- * Note that the low bits of the passed in "open_flag"
- * are not the same as in the local variable "flag". See
- * open_to_namei_flags() for more details.
- */
-struct file *do_filp_open(int dfd, const char *pathname,
+static struct file *path_openat(int dfd, const char *pathname,
                const struct open_flags *op, int flags)
 {
        struct file *filp;
        struct nameidata nd;
-       int error;
        struct path path;
        int count = 0;
+       int error;
 
        filp = get_empty_filp();
        if (!filp)
@@ -2319,42 +2314,27 @@ struct file *do_filp_open(int dfd, const char *pathname,
                goto creat;
 
        /* !O_CREAT, simple open */
-       error = do_path_lookup(dfd, pathname, flags | op->intent, &nd);
+       error = path_lookupat(dfd, pathname, flags | op->intent, &nd);
        if (unlikely(error))
-               goto out_filp2;
+               goto out_filp;
        error = -ELOOP;
        if (!(nd.flags & LOOKUP_FOLLOW)) {
                if (nd.inode->i_op->follow_link)
-                       goto out_path2;
+                       goto out_path;
        }
        error = -ENOTDIR;
        if (nd.flags & LOOKUP_DIRECTORY) {
                if (!nd.inode->i_op->lookup)
-                       goto out_path2;
+                       goto out_path;
        }
        audit_inode(pathname, nd.path.dentry);
        filp = finish_open(&nd, op->open_flag, op->acc_mode);
-out2:
        release_open_intent(&nd);
        return filp;
 
-out_path2:
-       path_put(&nd.path);
-out_filp2:
-       filp = ERR_PTR(error);
-       goto out2;
-
 creat:
        /* OK, have to create the file. Find the parent. */
-       error = path_lookupat(dfd, pathname,
-                       LOOKUP_PARENT | LOOKUP_RCU | flags, &nd);
-       if (unlikely(error == -ECHILD))
-               error = path_lookupat(dfd, pathname, LOOKUP_PARENT | flags, &nd);
-       if (unlikely(error == -ESTALE)) {
-reval:
-               flags |= LOOKUP_REVAL;
-               error = path_lookupat(dfd, pathname, LOOKUP_PARENT | flags, &nd);
-       }
+       error = path_lookupat(dfd, pathname, LOOKUP_PARENT | flags, &nd);
        if (unlikely(error))
                goto out_filp;
        if (unlikely(!audit_dummy_context()))
@@ -2398,8 +2378,6 @@ reval:
 out:
        if (nd.root.mnt)
                path_put(&nd.root);
-       if (filp == ERR_PTR(-ESTALE) && !(flags & LOOKUP_REVAL))
-               goto reval;
        release_open_intent(&nd);
        return filp;
 
@@ -2412,6 +2390,19 @@ out_filp:
        goto out;
 }
 
+struct file *do_filp_open(int dfd, const char *pathname,
+               const struct open_flags *op, int flags)
+{
+       struct file *filp;
+
+       filp = path_openat(dfd, pathname, op, flags | LOOKUP_RCU);
+       if (unlikely(filp == ERR_PTR(-ECHILD)))
+               filp = path_openat(dfd, pathname, op, flags);
+       if (unlikely(filp == ERR_PTR(-ESTALE)))
+               filp = path_openat(dfd, pathname, op, flags | LOOKUP_REVAL);
+       return filp;
+}
+
 /**
  * lookup_create - lookup a dentry, creating it if it doesn't exist
  * @nd: nameidata info