btrfs: factor stripe submission logic out of btrfs_map_bio

Move all per-stripe handling into submit_stripe_bio and use a label to
cleanup instead of duplicating the logic.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 04e7e79cab47c062d74249ad7e276b805bef136a..1e06b7ee6a815191a5a542031ef52e6c70778bf6 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6690,10 +6690,30 @@ static void btrfs_end_bio(struct bio *bio)
                btrfs_end_bioc(bioc, true);
 }
 
-static void submit_stripe_bio(struct btrfs_io_context *bioc, struct bio *bio,
-                             u64 physical, struct btrfs_device *dev)
+static void submit_stripe_bio(struct btrfs_io_context *bioc,
+                             struct bio *orig_bio, int dev_nr, bool clone)
 {
        struct btrfs_fs_info *fs_info = bioc->fs_info;
+       struct btrfs_device *dev = bioc->stripes[dev_nr].dev;
+       u64 physical = bioc->stripes[dev_nr].physical;
+       struct bio *bio;
+
+       if (!dev || !dev->bdev ||
+           test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) ||
+           (btrfs_op(orig_bio) == BTRFS_MAP_WRITE &&
+            !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))) {
+               atomic_inc(&bioc->error);
+               if (atomic_dec_and_test(&bioc->stripes_pending))
+                       btrfs_end_bioc(bioc, false);
+               return;
+       }
+
+       if (clone) {
+               bio = btrfs_bio_clone(dev->bdev, orig_bio);
+       } else {
+               bio = orig_bio;
+               bio_set_dev(bio, dev->bdev);
+       }
 
        bio->bi_private = bioc;
        btrfs_bio(bio)->device = dev;
@@ -6728,32 +6748,25 @@ static void submit_stripe_bio(struct btrfs_io_context *bioc, struct bio *bio,
 blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
                           int mirror_num)
 {
-       struct btrfs_device *dev;
-       struct bio *first_bio = bio;
        u64 logical = bio->bi_iter.bi_sector << 9;
-       u64 length = 0;
-       u64 map_length;
+       u64 length = bio->bi_iter.bi_size;
+       u64 map_length = length;
        int ret;
        int dev_nr;
        int total_devs;
        struct btrfs_io_context *bioc = NULL;
 
-       length = bio->bi_iter.bi_size;
-       map_length = length;
-
        btrfs_bio_counter_inc_blocked(fs_info);
        ret = __btrfs_map_block(fs_info, btrfs_op(bio), logical,
                                &map_length, &bioc, mirror_num, 1);
-       if (ret) {
-               btrfs_bio_counter_dec(fs_info);
-               return errno_to_blk_status(ret);
-       }
+       if (ret)
+               goto out_dec;
 
        total_devs = bioc->num_stripes;
-       bioc->orig_bio = first_bio;
-       bioc->private = first_bio->bi_private;
-       bioc->end_io = first_bio->bi_end_io;
-       atomic_set(&bioc->stripes_pending, bioc->num_stripes);
+       bioc->orig_bio = bio;
+       bioc->private = bio->bi_private;
+       bioc->end_io = bio->bi_end_io;
+       atomic_set(&bioc->stripes_pending, total_devs);
 
        if ((bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
            ((btrfs_op(bio) == BTRFS_MAP_WRITE) || (mirror_num > 1))) {
@@ -6765,9 +6778,7 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
                        ret = raid56_parity_recover(bio, bioc, map_length,
                                                    mirror_num, 1);
                }
-
-               btrfs_bio_counter_dec(fs_info);
-               return errno_to_blk_status(ret);
+               goto out_dec;
        }
 
        if (map_length < length) {
@@ -6778,28 +6789,13 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
        }
 
        for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
-               dev = bioc->stripes[dev_nr].dev;
-               if (!dev || !dev->bdev || test_bit(BTRFS_DEV_STATE_MISSING,
-                                                  &dev->dev_state) ||
-                   (btrfs_op(first_bio) == BTRFS_MAP_WRITE &&
-                   !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))) {
-                       atomic_inc(&bioc->error);
-                       if (atomic_dec_and_test(&bioc->stripes_pending))
-                               btrfs_end_bioc(bioc, false);
-                       continue;
-               }
-
-               if (dev_nr < total_devs - 1) {
-                       bio = btrfs_bio_clone(dev->bdev, first_bio);
-               } else {
-                       bio = first_bio;
-                       bio_set_dev(bio, dev->bdev);
-               }
+               const bool should_clone = (dev_nr < total_devs - 1);
 
-               submit_stripe_bio(bioc, bio, bioc->stripes[dev_nr].physical, dev);
+               submit_stripe_bio(bioc, bio, dev_nr, should_clone);
        }
+out_dec:
        btrfs_bio_counter_dec(fs_info);
-       return BLK_STS_OK;
+       return errno_to_blk_status(ret);
 }
 
 static bool dev_args_match_fs_devices(const struct btrfs_dev_lookup_args *args,