4 files changed, 8 insertions, 4 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 7397c622fb6a..8e7a78acf81a 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -505,7 +505,6 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
         struct block_device *bdev;
         struct bio *comp_bio;
         u64 cur_disk_byte = (u64)bio->bi_sector << 9;
-        u64 em_len;
         struct extent_map *em;
         int ret;
 
@@ -524,9 +523,8 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
         cb->errors = 0;
         cb->inode = inode;
 
-        cb->start = em->start;
+        cb->start = em->orig_start;
         compressed_len = em->block_len;
-        em_len = em->len;
         free_extent_map(em);
 
         cb->len = uncompressed_len;
@@ -545,7 +543,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
         }
         cb->nr_pages = nr_pages;
 
-        add_ra_bio_pages(inode, cb->start + em_len, cb);
+        add_ra_bio_pages(inode, em->start + em->len, cb);
 
         if (!btrfs_test_opt(root, NODATASUM) &&
             !btrfs_test_flag(inode, NODATASUM)) {
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index accfedaeb513..fb6eeef06bb0 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -20,6 +20,7 @@ struct extent_map {
         /* all of these are in bytes */
         u64 start;
         u64 len;
+        u64 orig_start;
         u64 block_start;
         u64 block_len;
         unsigned long flags;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 337221ecca27..85841c538805 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -222,6 +222,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                     em->start < start) {
                         split->start = em->start;
                         split->len = start - em->start;
+                        split->orig_start = em->orig_start;
                         split->block_start = em->block_start;
 
                         if (compressed)
@@ -243,6 +244,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 
                         split->start = start + len;
                         split->len = em->start + em->len - (start + len);
+                        split->orig_start = em->orig_start;
                         split->bdev = em->bdev;
                         split->flags = flags;
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e01c0d0310ab..59660293d291 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3949,6 +3949,8 @@ again:
             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
                 em->start = extent_start;
                 em->len = extent_end - extent_start;
+                em->orig_start = extent_start -
+                                 btrfs_file_extent_offset(leaf, item);
                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
                 if (bytenr == 0) {
                         em->block_start = EXTENT_MAP_HOLE;
@@ -3988,6 +3990,7 @@ again:
                 em->start = extent_start + extent_offset;
                 em->len = (copy_size + root->sectorsize - 1) &
                         ~((u64)root->sectorsize - 1);
+                em->orig_start = EXTENT_MAP_INLINE;
                 if (compressed)
                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;