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-rw-r--r--fs/btrfs/compression.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 18579b904d5c..41ee862470b0 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -682,6 +682,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
struct page *page;
struct bio *comp_bio;
u64 cur_disk_byte = bio->bi_iter.bi_sector << 9;
+ u64 file_offset;
u64 em_len;
u64 em_start;
struct extent_map *em;
@@ -691,15 +692,17 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
em_tree = &BTRFS_I(inode)->extent_tree;
+ file_offset = bio_first_bvec_all(bio)->bv_offset +
+ page_offset(bio_first_page_all(bio));
+
/* we need the actual starting offset of this extent in the file */
read_lock(&em_tree->lock);
- em = lookup_extent_mapping(em_tree,
- page_offset(bio_first_page_all(bio)),
- fs_info->sectorsize);
+ em = lookup_extent_mapping(em_tree, file_offset, fs_info->sectorsize);
read_unlock(&em_tree->lock);
if (!em)
return BLK_STS_IOERR;
+ ASSERT(em->compress_type != BTRFS_COMPRESS_NONE);
compressed_len = em->block_len;
cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS);
if (!cb)