1 files changed, 13 insertions, 8 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7c4e6ccdba3f..4b5398c9f62b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5794,7 +5794,9 @@ out:
  * block must be cow'd
  */
 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
-                                      struct inode *inode, u64 offset, u64 len)
+                                      struct inode *inode, u64 offset, u64 *len,
+                                      u64 *orig_start, u64 *orig_block_len,
+                                      u64 *ram_bytes)
 {
         struct btrfs_path *path;
         int ret;
@@ -5851,8 +5853,12 @@ static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
         backref_offset = btrfs_file_extent_offset(leaf, fi);
 
+        *orig_start = key.offset - backref_offset;
+        *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
+        *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
+
         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
-        if (extent_end < offset + len) {
+        if (extent_end < offset + *len) {
                 /* extent doesn't include our full range, must cow */
                 goto out;
         }
@@ -5876,13 +5882,14 @@ static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
          */
         disk_bytenr += backref_offset;
         disk_bytenr += offset - key.offset;
-        num_bytes = min(offset + len, extent_end) - offset;
+        num_bytes = min(offset + *len, extent_end) - offset;
         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
                                 goto out;
         /*
          * all of the above have passed, it is safe to overwrite this extent
          * without cow
          */
+        *len = num_bytes;
         ret = 1;
 out:
         btrfs_free_path(path);
@@ -6092,7 +6099,7 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
              em->block_start != EXTENT_MAP_HOLE)) {
                 int type;
                 int ret;
-                u64 block_start;
+                u64 block_start, orig_start, orig_block_len, ram_bytes;
 
                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
                         type = BTRFS_ORDERED_PREALLOC;
@@ -6110,10 +6117,8 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
                 if (IS_ERR(trans))
                         goto must_cow;
 
-                if (can_nocow_odirect(trans, inode, start, len) == 1) {
-                        u64 orig_start = em->orig_start;
-                        u64 orig_block_len = em->orig_block_len;
-
+                if (can_nocow_odirect(trans, inode, start, &len, &orig_start,
+                                      &orig_block_len, &ram_bytes) == 1) {
                         if (type == BTRFS_ORDERED_PREALLOC) {
                                 free_extent_map(em);
                                 em = create_pinned_em(inode, start, len,