Re: Bug in btrfs_rename (kernel BUG at fs/btrfs/inode.c:5595!)

[Josef Bacik <josef@redhat.com>]

On Thu, Jan 14, 2010 at 12:03:23PM -0500, Josef Bacik wrote:
> On Wed, Jan 13, 2010 at 09:11:59PM +0100, Tomas Carnecky wrote:
> >  On 1/13/10 9:13 PM, Josef Bacik wrote:
> >> On Wed, Jan 13, 2010 at 08:09:17PM +0100, Tomas Carnecky wrote:
> >>>   I was running v2.6.33-rc2-187-g08d869a and everything was ok. Today I
> >>> decided to update the kernel (to v2.6.33-rc4) and a minute or two after
> >>> logging into the gnome desktop this kernel bug appeared in dmesg. I then
> >>> went back to the old kernel but the bug didn't disappear, not even after
> >>> running btrfsck on the filesystem.
> >>>
> >> Ok will you please run with this patch?  It shouldn't panic your box, since it
> >> seems ret is -EEXIST.  Just watch your logs for
> >>
> >> OH NO, ORPHAN ENTRY ALREADY EXISTS FOR<number>
> >>
> >> and then look up and find all occurances of
> >>
> >> Btrfs: orphan add<number>
> >>
> >> with the stack trace and send it back to me so I can verify that nothing heinous
> >> is happening.  I assume we're just racing with unlink/rename so all that needs
> >> to be done is to take that BUG_ON out, but it would be nice to know for sure.
> >
> 
> Ok will you try this patch?  I've not built it, so sorry if it doesn't compile
> :).  Look for the "OH NO" messages again.  If they show up then the problem is
> still there, if they go away the problem is fixed.  I tried to reproduce this
> locally but I can't seem to do it, so you are my only hope :).  
> 
> By the way, this replaces the last patch I sent you, so unapply the previous
> patch and apply this one instead.  Thanks,
> 

Ok here's the final version of the patch I'm going to post.  This replaces the
other patches that I sent you, so un-apply the last one you applied and apply
this one instead.  Run this for a day and let me know if you have any problems.
If no problems I'll go ahead and post it.  Thanks,

Josef


diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5440bab..24cbf6b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3305,24 +3305,7 @@ static int btrfs_setattr_size(struct inode *inode, struct iattr *attr)
 			send_sig(SIGXFSZ, current, 0);
 			return -EFBIG;
 		}
-	}
-
-	ret = btrfs_reserve_metadata_space(root, 1);
-	if (ret)
-		return ret;
-
-	trans = btrfs_start_transaction(root, 1);
-	btrfs_set_trans_block_group(trans, inode);
-
-	ret = btrfs_orphan_add(trans, inode);
-	BUG_ON(ret);
-
-	nr = trans->blocks_used;
-	btrfs_end_transaction(trans, root);
-	btrfs_unreserve_metadata_space(root, 1);
-	btrfs_btree_balance_dirty(root, nr);
 
-	if (attr->ia_size > inode->i_size) {
 		ret = btrfs_cont_expand(inode, attr->ia_size);
 		if (ret) {
 			btrfs_truncate(inode);
@@ -3337,14 +3320,26 @@ static int btrfs_setattr_size(struct inode *inode, struct iattr *attr)
 
 		ret = btrfs_update_inode(trans, root, inode);
 		BUG_ON(ret);
-		if (inode->i_nlink > 0) {
-			ret = btrfs_orphan_del(trans, inode);
-			BUG_ON(ret);
-		}
+
 		nr = trans->blocks_used;
 		btrfs_end_transaction(trans, root);
 		btrfs_btree_balance_dirty(root, nr);
 		return 0;
+	} else if (attr->ia_size < i_size_read(inode)) {
+		ret = btrfs_reserve_metadata_space(root, 1);
+		if (ret)
+			return ret;
+
+		trans = btrfs_start_transaction(root, 1);
+		btrfs_set_trans_block_group(trans, inode);
+
+		ret = btrfs_orphan_add(trans, inode);
+		BUG_ON(ret);
+
+		nr = trans->blocks_used;
+		btrfs_end_transaction(trans, root);
+		btrfs_unreserve_metadata_space(root, 1);
+		btrfs_btree_balance_dirty(root, nr);
 	}
 
 	/*
@@ -3355,10 +3350,6 @@ static int btrfs_setattr_size(struct inode *inode, struct iattr *attr)
 	if (attr->ia_size == 0)
 		BTRFS_I(inode)->ordered_data_close = 1;
 
-	/* we don't support swapfiles, so vmtruncate shouldn't fail */
-	ret = vmtruncate(inode, attr->ia_size);
-	BUG_ON(ret);
-
 	return 0;
 }
 
@@ -3376,7 +3367,6 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
 		if (err)
 			return err;
 	}
-	attr->ia_valid &= ~ATTR_SIZE;
 
 	if (attr->ia_valid)
 		err = inode_setattr(inode, attr);