Fix the -ESTALE handling in do_filp_open()

Instead of playing sick games with path saving, cleanups, just retry
the entire thing once with LOOKUP_REVAL added.  Post-.34 we'll convert
all -ESTALE handling in there to that style, rather than playing with
many retry loops deep in the call chain.

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

diff --git a/fs/namei.c b/fs/namei.c
index d930f18..94a5e60 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1604,11 +1604,12 @@ struct file *do_filp_open(int dfd, const char *pathname,
        struct file *filp;
        struct nameidata nd;
        int error;
-       struct path path, save;
+       struct path path;
        struct dentry *dir;
        int count = 0;
        int will_truncate;
        int flag = open_to_namei_flags(open_flag);
+       int force_reval = 0;
 
        /*
         * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
@@ -1660,9 +1661,12 @@ struct file *do_filp_open(int dfd, const char *pathname,
        /*
         * Create - we need to know the parent.
         */
+reval:
        error = path_init(dfd, pathname, LOOKUP_PARENT, &nd);
        if (error)
                return ERR_PTR(error);
+       if (force_reval)
+               nd.flags |= LOOKUP_REVAL;
        error = path_walk(pathname, &nd);
        if (error) {
                if (nd.root.mnt)
@@ -1854,17 +1858,7 @@ do_link:
        error = security_inode_follow_link(path.dentry, &nd);
        if (error)
                goto exit_dput;
-       save = nd.path;
-       path_get(&save);
        error = __do_follow_link(&path, &nd);
-       if (error == -ESTALE) {
-               /* nd.path had been dropped */
-               nd.path = save;
-               path_get(&nd.path);
-               nd.flags |= LOOKUP_REVAL;
-               error = __do_follow_link(&path, &nd);
-       }
-       path_put(&save);
        path_put(&path);
        if (error) {
                /* Does someone understand code flow here? Or it is only
@@ -1874,6 +1868,10 @@ do_link:
                release_open_intent(&nd);
                if (nd.root.mnt)
                        path_put(&nd.root);
+               if (error == -ESTALE && !force_reval) {
+                       force_reval = 1;
+                       goto reval;
+               }
                return ERR_PTR(error);
        }
        nd.flags &= ~LOOKUP_PARENT;