Btrfs: Fix logic to avoid reading checksums for -o nodatasum,compress

When compression was on, we were improperly ignoring -o nodatasum.  This
reworks the logic a bit to properly honor all the flags.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6739424c0fe6..dd9cd01042b8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -833,28 +833,29 @@ int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         int ret = 0;
+        int skip_sum;
 
         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
         BUG_ON(ret);
 
-        if (btrfs_test_opt(root, NODATASUM) ||
-            btrfs_test_flag(inode, NODATASUM)) {
-                goto mapit;
-        }
+        skip_sum = btrfs_test_opt(root, NODATASUM) ||
+                btrfs_test_flag(inode, NODATASUM);
 
         if (!(rw & (1 << BIO_RW))) {
-                btrfs_lookup_bio_sums(root, inode, bio);
+                if (!skip_sum)
+                        btrfs_lookup_bio_sums(root, inode, bio);
 
-                if (bio_flags & EXTENT_BIO_COMPRESSED) {
+                if (bio_flags & EXTENT_BIO_COMPRESSED)
                         return btrfs_submit_compressed_read(inode, bio,
                                                     mirror_num, bio_flags);
-                }
-
                 goto mapit;
-        }
-        return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
+        } else if (!skip_sum) {
+                /* we're doing a write, do the async checksumming */
+                return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
                                    inode, rw, bio, mirror_num,
                                    bio_flags, __btrfs_submit_bio_hook);
+        }
+
 mapit:
         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
 }