Re: [PATCH] Re: fs corruption with invalidate_buffers()

From: Udo A. Steinberg (sorisor@Hell.WH8.TU-Dresden.De)
Date: Thu Dec 07 2000 - 17:03:31 EST


Jan Niehusmann wrote:
>
> The following patch actually prevents the corruption I described.
>
> I'd like to hear from the people having problems with hdparm, if it helps
> them, too.

Yes, it prevents the issue.

> Please note that the patch circumvents the problem more than it fixes it.
> The true fix would invalidate the mappings, but I don't know how to do it.

I don't know either. What does Alexander Viro say to all of this?

-Udo.

Same debug patch adapted to test12-pre7 follows:
 
--- linux/fs/buffer.c Thu Dec 7 22:55:54 2000
+++ /usr/src/linux/fs/buffer.c Thu Dec 7 22:49:02 2000
@@ -627,7 +627,7 @@
    then an invalidate_buffers call that doesn't trash dirty buffers. */
 void __invalidate_buffers(kdev_t dev, int destroy_dirty_buffers)
 {
- int i, nlist, slept;
+ int i, nlist, slept, db_message = 0;
        struct buffer_head * bh, * bh_next;
 
  retry:
@@ -653,9 +653,13 @@
                        write_lock(&hash_table_lock);
                        if (!atomic_read(&bh->b_count) &&
                            (destroy_dirty_buffers || !buffer_dirty(bh))) {
- remove_inode_queue(bh);
- __remove_from_queues(bh);
- put_last_free(bh);
+ if (bh->b_page && bh->b_page->mapping)
+ db_message = 1;
+ else {
+ remove_inode_queue(bh);
+ __remove_from_queues(bh);
+ put_last_free(bh);
+ }
                        }
                        /* else complain loudly? */
 
@@ -668,6 +672,8 @@
        spin_unlock(&lru_list_lock);
        if (slept)
                goto retry;
+ if (db_message)
+ printk("invalidate_buffers with mapped page!\n");
 }
 
 void set_blocksize(kdev_t dev, int size)
-
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