Re: corruption

From: Stephen C. Tweedie (sct@redhat.com)
Date: Fri Dec 01 2000 - 09:16:59 EST


Hi,

On Fri, Dec 01, 2000 at 08:35:41AM +1100, Andrew Morton wrote:
>
> I bet this'll catch it:
>
> static __inline__ void list_del(struct list_head *entry)
> {
> __list_del(entry->prev, entry->next);
> + entry->next = entry->prev = 0;
> }

No, because the buffer hash list is never referenced unless
buffer->b_inode is non-null, so we can't ever do a double-list_del on
the buffer.

The patch below should fix it. It has been sent to Linus. The
important part is the first hunk of the inode.c diff.

Cheers,
 Stephen

fsync-fix2.diff:
--- fs/buffer.c.~1~ Wed Nov 29 15:16:43 2000
+++ fs/buffer.c Fri Dec 1 00:41:28 2000
@@ -871,10 +871,11 @@
                 else {
                         bh->b_inode = &tmp;
                         list_add(&bh->b_inode_buffers, &tmp.i_dirty_buffers);
- atomic_inc(&bh->b_count);
                         if (buffer_dirty(bh)) {
+ atomic_inc(&bh->b_count);
                                 spin_unlock(&lru_list_lock);
                                 ll_rw_block(WRITE, 1, &bh);
+ brelse(bh);
                                 spin_lock(&lru_list_lock);
                         }
                 }
@@ -883,6 +884,7 @@
         while (!list_empty(&tmp.i_dirty_buffers)) {
                 bh = BH_ENTRY(tmp.i_dirty_buffers.prev);
                 remove_inode_queue(bh);
+ atomic_inc(&bh->b_count);
                 spin_unlock(&lru_list_lock);
                 wait_on_buffer(bh);
                 if (!buffer_uptodate(bh))
@@ -929,9 +931,9 @@
                         atomic_inc(&bh->b_count);
                         spin_unlock(&lru_list_lock);
                         wait_on_buffer(bh);
- brelse(bh);
                         if (!buffer_uptodate(bh))
                                 err = -EIO;
+ brelse(bh);
                         spin_lock(&lru_list_lock);
                         goto repeat;
                 }
--- fs/inode.c.~1~ Wed Nov 29 15:16:43 2000
+++ fs/inode.c Fri Dec 1 00:40:26 2000
@@ -77,7 +77,13 @@
 
 #define alloc_inode() \
          ((struct inode *) kmem_cache_alloc(inode_cachep, SLAB_KERNEL))
-#define destroy_inode(inode) kmem_cache_free(inode_cachep, (inode))
+static void destroy_inode(struct inode *inode)
+{
+ if (!list_empty(&inode->i_dirty_buffers))
+ BUG();
+ kmem_cache_free(inode_cachep, (inode));
+}
+
 
 /*
  * These are initializations that only need to be done
@@ -348,6 +354,12 @@
  
 void clear_inode(struct inode *inode)
 {
+ if (!list_empty(&inode->i_dirty_buffers)) {
+ if (inode->i_nlink)
+ BUG();
+ invalidate_inode_buffers(inode);
+ }
+
         if (inode->i_data.nrpages)
                 BUG();
         if (!(inode->i_state & I_FREEING))
@@ -407,6 +419,7 @@
                 inode = list_entry(tmp, struct inode, i_list);
                 if (inode->i_sb != sb)
                         continue;
+ invalidate_inode_buffers(inode);
                 if (!atomic_read(&inode->i_count)) {
                         list_del(&inode->i_hash);
                         INIT_LIST_HEAD(&inode->i_hash);
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Thu Dec 07 2000 - 21:00:07 EST