GIT: unionfs2-2.6.27.y: Unionfs: better error handling in rename code when copyups are involved

[Erez Zadok]

commit 5b6873f8a3bab4fd4fed466d2e24bde8bf77a856
Author: Erez_Zadok <ezk at cs.sunysb.edu>
Date:   Mon Jul 9 20:14:41 2007 -0400

    Unionfs: better error handling in rename code when copyups are involved
    
    First, rewrite code slightly and document it better to explain why we appear
    to ignore copyup errors (because we try the next branch to the left).
    
    Second, change a BUG_ON to a printk(KERN_ERR), because a mild failure to
    copyup a file should not cause an oops.  For example, some file systems
    don't support UIDs/GIDs (e.g., VFAT) and others don't allow you to chmod a
    symlink (e.g., jffs2), possibly resulting in mild copyup failures; that
    shouldn't be considered so severe as to cause an oops.
    
    Signed-off-by: Erez Zadok <ezk at cs.sunysb.edu>

diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c
index 0316258..1761f8b 100644
--- a/fs/unionfs/rename.c
+++ b/fs/unionfs/rename.c
@@ -230,14 +230,15 @@ static int do_unionfs_rename(struct inode *old_dir,
 					    old_dentry->d_name.name,
 					    old_dentry->d_name.len,
 					    NULL, old_dentry->d_inode->i_size);
-			if (!err) {
-				dput(wh_old);
-				bwh_old = bindex;
-				err = __unionfs_rename(old_dir, old_dentry,
-						       new_dir, new_dentry,
-						       bindex, &wh_old);
-				break;
-			}
+			/* if copyup failed, try next branch to the left */
+			if (err)
+				continue;
+			dput(wh_old);
+			bwh_old = bindex;
+			err = __unionfs_rename(old_dir, old_dentry,
+					       new_dir, new_dentry,
+					       bindex, &wh_old);
+			break;
 		}
 	}
 
@@ -255,7 +256,13 @@ static int do_unionfs_rename(struct inode *old_dir,
 	 */
 	if ((old_bstart != old_bend) || (do_copyup != -1)) {
 		struct dentry *lower_parent;
-		BUG_ON(!wh_old || wh_old->d_inode || bwh_old < 0);
+		if (!wh_old || wh_old->d_inode || bwh_old < 0) {
+			printk(KERN_ERR "unionfs: rename error "
+			       "(wh_old=%p/%p bwh_old=%d)\n", wh_old,
+			       (wh_old ? wh_old->d_inode : NULL), bwh_old);
+			err = -EIO;
+			goto out;
+		}
 		lower_parent = lock_parent(wh_old);
 		local_err = vfs_create(lower_parent->d_inode, wh_old, S_IRUGO,
 				       NULL);