Re: [PATCH 1/3] enhanced ESTALE error handling

[Peter Staubach]

Matthew Wilcox wrote:

On Fri, Jan 18, 2008 at 10:36:01AM -0500, Peter Staubach wrote:

@@ -1025,12 +1027,27 @@ static int fastcall link_path_walk(const
        mntget(save.mnt);

result = __link_path_walk(name, nd);

-       if (result == -ESTALE) {
+       while (result == -ESTALE) {
+               /*
+                * If no progress was made looking up the pathname,
+                * then stop and return ENOENT instead of ESTALE.
+                */
+               if (nd->dentry == save.dentry) {
+                       result = -ENOENT;
+                       break;
+               }
                *nd = save;
                dget(nd->dentry);
                mntget(nd->mnt);
                nd->flags |= LOOKUP_REVAL;
                result = __link_path_walk(name, nd);
+               /*
+                * If no progress was made this time, then return
+                * ENOENT instead of ESTALE because no recovery
+                * is possible to recover the stale file handle.
+                */
+               if (result == -ESTALE && nd->dentry == save.dentry)
+                       result = -ENOENT;
        }

dput(save.dentry);

Why do you need both of these tests?  The first one should be enough,
surely?

Yes, good point.

@@ -1268,8 +1285,8 @@ int path_lookup_open(int dfd, const char
  * @create_mode: create intent flags
  */
 static int path_lookup_create(int dfd, const char *name,
-                             unsigned int lookup_flags, struct nameidata *nd,
-                             int open_flags, int create_mode)
+               unsigned int lookup_flags, struct nameidata *nd,
+               int open_flags, int create_mode)

Gratuitous reformatting?

Elimination of an overly long line?

@@ -1712,7 +1729,10 @@ int open_namei(int dfd, const char *path
        int acc_mode, error;
        struct path path;
        struct dentry *dir;
-       int count = 0;
+       int count;
+
+top:
+       count = 0;

acc_mode = ACC_MODE(flag); @@ -1739,7 +1759,8 @@ int open_namei(int dfd, const char *path

        /*
         * Create - we need to know the parent.
         */
-       error = path_lookup_create(dfd,pathname,LOOKUP_PARENT,nd,flag,mode);
+       error = path_lookup_create(dfd, pathname, LOOKUP_PARENT, nd,
+                               flag, mode);
        if (error)
                return error;

@@ -1812,10 +1833,17 @@ ok:

        return 0;

exit_dput:

+       if (error == -ESTALE)
+               d_drop(path.dentry);
        dput_path(&path, nd);
 exit:
        if (!IS_ERR(nd->intent.open.file))
                release_open_intent(nd);
+       if (error == -ESTALE) {
+               d_drop(nd->dentry);
+               path_release(nd);
+               goto top;
+       }

I wonder if a tail-call might not work better here.

"Tail-call"?

   Thanx...

      ps
-
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