1 files changed, 92 insertions, 0 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c9446d4840ed..a3b0676403f7 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2854,6 +2854,98 @@ out:
         return sector;
 }
 
+int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+                __u64 start, __u64 len, get_extent_t *get_extent)
+{
+        int ret;
+        u64 off = start;
+        u64 max = start + len;
+        u32 flags = 0;
+        u64 disko = 0;
+        struct extent_map *em = NULL;
+        int end = 0;
+        u64 em_start = 0, em_len = 0;
+        unsigned long emflags;
+        ret = 0;
+
+        if (len == 0)
+                return -EINVAL;
+
+        lock_extent(&BTRFS_I(inode)->io_tree, start, start + len,
+                GFP_NOFS);
+        em = get_extent(inode, NULL, 0, off, max - off, 0);
+        if (!em)
+                goto out;
+        if (IS_ERR(em)) {
+                ret = PTR_ERR(em);
+                goto out;
+        }
+        while (!end) {
+                off = em->start + em->len;
+                if (off >= max)
+                        end = 1;
+
+                em_start = em->start;
+                em_len = em->len;
+
+                disko = 0;
+                flags = 0;
+
+                switch (em->block_start) {
+                case EXTENT_MAP_LAST_BYTE:
+                        end = 1;
+                        flags |= FIEMAP_EXTENT_LAST;
+                        break;
+                case EXTENT_MAP_HOLE:
+                        flags |= FIEMAP_EXTENT_UNWRITTEN;
+                        break;
+                case EXTENT_MAP_INLINE:
+                        flags |= (FIEMAP_EXTENT_DATA_INLINE |
+                                  FIEMAP_EXTENT_NOT_ALIGNED);
+                        break;
+                case EXTENT_MAP_DELALLOC:
+                        flags |= (FIEMAP_EXTENT_DELALLOC |
+                                  FIEMAP_EXTENT_UNKNOWN);
+                        break;
+                default:
+                        disko = em->block_start;
+                        break;
+                }
+                if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
+                        flags |= FIEMAP_EXTENT_ENCODED;
+
+                emflags = em->flags;
+                free_extent_map(em);
+                em = NULL;
+
+                if (!end) {
+                        em = get_extent(inode, NULL, 0, off, max - off, 0);
+                        if (!em)
+                                goto out;
+                        if (IS_ERR(em)) {
+                                ret = PTR_ERR(em);
+                                goto out;
+                        }
+                        emflags = em->flags;
+                }
+                if (test_bit(EXTENT_FLAG_VACANCY, &emflags)) {
+                        flags |= FIEMAP_EXTENT_LAST;
+                        end = 1;
+                }
+
+                ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
+                                        em_len, flags);
+                if (ret)
+                        goto out_free;
+        }
+out_free:
+        free_extent_map(em);
+out:
+        unlock_extent(&BTRFS_I(inode)->io_tree, start, start + len,
+                        GFP_NOFS);
+        return ret;
+}
+
 static inline struct page *extent_buffer_page(struct extent_buffer *eb,
                                               unsigned long i)
 {