1 files changed, 46 insertions, 1 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9fbda6552069..3f5525f0834c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -356,12 +356,23 @@ out_unlock:
 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
 {
         struct extent_map *em;
+        struct extent_map *split = NULL;
+        struct extent_map *split2 = NULL;
         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
         u64 len = end - start + 1;
+        int ret;
+        int testend = 1;
 
-        if (end == (u64)-1)
+        if (end == (u64)-1) {
                 len = (u64)-1;
+                testend = 0;
+        }
         while(1) {
+                if (!split)
+                        split = alloc_extent_map(GFP_NOFS);
+                if (!split2)
+                        split2 = alloc_extent_map(GFP_NOFS);
+
                 spin_lock(&em_tree->lock);
                 em = lookup_extent_mapping(em_tree, start, len);
                 if (!em) {
@@ -369,6 +380,36 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
                         break;
                 }
                 remove_extent_mapping(em_tree, em);
+
+                if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+                    em->start < start) {
+                        split->start = em->start;
+                        split->len = start - em->start;
+                        split->block_start = em->block_start;
+                        split->bdev = em->bdev;
+                        split->flags = em->flags;
+                        ret = add_extent_mapping(em_tree, split);
+                        BUG_ON(ret);
+                        free_extent_map(split);
+                        split = split2;
+                        split2 = NULL;
+                }
+                if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+                    testend && em->start + em->len > start + len) {
+                        u64 diff = start + len - em->start;
+
+                        split->start = start + len;
+                        split->len = em->start + em->len - (start + len);
+                        split->bdev = em->bdev;
+                        split->flags = em->flags;
+
+                        split->block_start = em->block_start + diff;
+
+                        ret = add_extent_mapping(em_tree, split);
+                        BUG_ON(ret);
+                        free_extent_map(split);
+                        split = NULL;
+                }
                 spin_unlock(&em_tree->lock);
 
                 /* once for us */
@@ -376,6 +417,10 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
                 /* once for the tree*/
                 free_extent_map(em);
         }
+        if (split)
+                free_extent_map(split);
+        if (split2)
+                free_extent_map(split2);
         return 0;
 }