Btrfs: Fix add_extent_mapping to check for duplicates across the whole range

add_extent_mapping was allowing the insertion of overlapping extents.
This never used to happen because it only inserted the extents from disk
and those were never overlapping.

But, with the data=ordered code, the disk and memory representations of the
file are not the same.  add_extent_mapping needs to ensure a new extent
does not overlap before it inserts.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

2 files changed, 24 insertions, 4 deletions

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 954b047639ab..78ced11d18c7 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -207,7 +207,14 @@ int add_extent_mapping(struct extent_map_tree *tree,
         int ret = 0;
         struct extent_map *merge = NULL;
         struct rb_node *rb;
+        struct extent_map *exist;
 
+        exist = lookup_extent_mapping(tree, em->start, em->len);
+        if (exist) {
+                free_extent_map(exist);
+                ret = -EEXIST;
+                goto out;
+        }
         assert_spin_locked(&tree->lock);
         rb = tree_insert(&tree->map, em->start, &em->rb_node);
         if (rb) {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 65107894a5bb..6c778043207d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -641,8 +641,9 @@ int btrfs_readpage_io_hook(struct page *page, u64 start, u64 end)
                 if (ret == -ENOENT || ret == -EFBIG)
                         ret = 0;
                 csum = 0;
-                printk("no csum found for inode %lu start %Lu\n", inode->i_ino,
-                       start);
+                if (printk_ratelimit())
+                        printk("no csum found for inode %lu start %Lu\n", inode->i_ino,
+                               start);
                 goto out;
         }
         read_extent_buffer(path->nodes[0], &csum, (unsigned long)item,
@@ -1653,8 +1654,20 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
                 btrfs_truncate_page(inode->i_mapping, inode->i_size);
 
                 hole_size = block_end - hole_start;
-                btrfs_wait_ordered_range(inode, hole_start, hole_size);
-                lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+                while(1) {
+                        struct btrfs_ordered_extent *ordered;
+                        btrfs_wait_ordered_range(inode, hole_start, hole_size);
+
+                        lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+                        ordered = btrfs_lookup_ordered_extent(inode, hole_start);
+                        if (ordered) {
+                                unlock_extent(io_tree, hole_start,
+                                              block_end - 1, GFP_NOFS);
+                                btrfs_put_ordered_extent(ordered);
+                        } else {
+                                break;
+                        }
+                }
 
                 trans = btrfs_start_transaction(root, 1);
                 btrfs_set_trans_block_group(trans, inode);