Re: [PATCH] 2.5.50: unused code in link_path_walk()

Re: [PATCH] 2.5.50: unused code in link_path_walk()

[Matthew Wilcox]

@@ -700,7 +700,6 @@
                                 if (this.name[1] != '.')
                                         break;
                                 follow_dotdot(&nd->mnt, &nd->dentry);
-				inode = nd->dentry->d_inode;
                                 /* fallthrough */
                         case 1:
                                 goto return_base;

seems broken to me.  if follow_dotdot() changes nd->dentry (can happen!),
inode needs to be changed.  look:

        inode = nd->dentry->d_inode;
        for(;;) {
                err = exec_permission_lite(inode);
                if (this.name[0] == '.') switch (this.len) {
                        case 2: 
                                if (this.name[1] != '.')
                                        break;
                                follow_dotdot(&nd->mnt, &nd->dentry);
                                inode = nd->dentry->d_inode;
                                /* fallthrough */
                        case 1:
                                continue;
                }
        }

btw, you should cc linux-fsdevel for patches to the VFS.

-- 
"It's not Hollywood.  War is real, war is primarily not about defeat or
victory, it is about death.  I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk

Re: [PATCH] 2.5.50: unused code in link_path_walk()

[Olaf Dietsche]

Matthew Wilcox <willy@debian.org> writes:

> @@ -700,7 +700,6 @@
>                                  if (this.name[1] != '.')
>                                          break;
>                                  follow_dotdot(&nd->mnt, &nd->dentry);
> -				inode = nd->dentry->d_inode;
>                                  /* fallthrough */
>                          case 1:
>                                  goto return_base;
>
> seems broken to me.  if follow_dotdot() changes nd->dentry (can happen!),
> inode needs to be changed.  look:
>
>         inode = nd->dentry->d_inode;
>         for(;;) {
>                 err = exec_permission_lite(inode);
>                 if (this.name[0] == '.') switch (this.len) {
>                         case 2: 
>                                 if (this.name[1] != '.')
>                                         break;
>                                 follow_dotdot(&nd->mnt, &nd->dentry);
>                                 inode = nd->dentry->d_inode;
>                                 /* fallthrough */
>                         case 1:
>                                 continue;
>                 }
>         }

You looked at the _first_ switch statement. You must go further down
to the _second_ switch. *There*, you don't need this assignment, AFAICS.

> btw, you should cc linux-fsdevel for patches to the VFS.

Thanks for this pointer, I'll spam linux-fsdevel in the future ;-).

Regards, Olaf.

[PATCH] 2.5.50: unused code in link_path_walk()

[Olaf Dietsche]

This patch removes one unnecessary line of code.

Regards, Olaf.

diff -urN a/fs/namei.c b/fs/namei.c
--- a/fs/namei.c	Thu Nov 28 20:44:46 2002
+++ b/fs/namei.c	Wed Dec  4 23:04:54 2002
@@ -700,7 +700,6 @@
 				if (this.name[1] != '.')
 					break;
 				follow_dotdot(&nd->mnt, &nd->dentry);
-				inode = nd->dentry->d_inode;
 				/* fallthrough */
 			case 1:
 				goto return_base;