2 files changed, 19 insertions, 9 deletions

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index 970d38f30565..788865df1bc9 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -127,14 +127,20 @@ struct afs_cell *afs_cell_create(const char *name, char *vllist)
 
         _enter("%s,%s", name, vllist);
 
+        down_write(&afs_cells_sem);
+        read_lock(&afs_cells_lock);
+        list_for_each_entry(cell, &afs_cells, link) {
+                if (strcasecmp(cell->name, name) == 0)
+                        goto duplicate_name;
+        }
+        read_unlock(&afs_cells_lock);
+
         cell = afs_cell_alloc(name, vllist);
         if (IS_ERR(cell)) {
                 _leave(" = %ld", PTR_ERR(cell));
                 return cell;
         }
 
-        down_write(&afs_cells_sem);
-
         /* add a proc directory for this cell */
         ret = afs_proc_cell_setup(cell);
         if (ret < 0)
@@ -167,6 +173,11 @@ error:
         kfree(cell);
         _leave(" = %d", ret);
         return ERR_PTR(ret);
+
+duplicate_name:
+        read_unlock(&afs_cells_lock);
+        up_write(&afs_cells_sem);
+        return ERR_PTR(-EEXIST);
 }
 
 /*
diff --git a/fs/buffer.c b/fs/buffer.c
index 7ba58386beee..98196327ddf0 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2564,14 +2564,13 @@ int nobh_write_end(struct file *file, struct address_space *mapping,
         struct inode *inode = page->mapping->host;
         struct buffer_head *head = fsdata;
         struct buffer_head *bh;
+        BUG_ON(fsdata != NULL && page_has_buffers(page));
 
-        if (!PageMappedToDisk(page)) {
-                if (unlikely(copied < len) && !page_has_buffers(page))
-                        attach_nobh_buffers(page, head);
-                if (page_has_buffers(page))
-                        return generic_write_end(file, mapping, pos, len,
-                                                copied, page, fsdata);
-        }
+        if (unlikely(copied < len) && !page_has_buffers(page))
+                attach_nobh_buffers(page, head);
+        if (page_has_buffers(page))
+                return generic_write_end(file, mapping, pos, len,
+                                        copied, page, fsdata);
 
         SetPageUptodate(page);
         set_page_dirty(page);