btrfs: use on-stack bio in repair_io_failure

The I/O in repair_io_failue is synchronous and doesn't need a btrfs_bio,
so just use an on-stack bio.  Also cleanup the error handling to use goto
labels and not discard the actual return values.

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

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a26290a..3d35997 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2305,12 +2305,13 @@ static int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
                             u64 length, u64 logical, struct page *page,
                             unsigned int pg_offset, int mirror_num)
 {
-       struct bio *bio;
        struct btrfs_device *dev;
+       struct bio_vec bvec;
+       struct bio bio;
        u64 map_length = 0;
        u64 sector;
        struct btrfs_io_context *bioc = NULL;
-       int ret;
+       int ret = 0;
 
        ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
        BUG_ON(!mirror_num);
@@ -2318,8 +2319,6 @@ static int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
        if (btrfs_repair_one_zone(fs_info, logical))
                return 0;
 
-       bio = btrfs_bio_alloc(1);
-       bio->bi_iter.bi_size = 0;
        map_length = length;
 
        /*
@@ -2337,53 +2336,50 @@ static int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
                 */
                ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
                                      &map_length, &bioc, 0);
-               if (ret) {
-                       btrfs_bio_counter_dec(fs_info);
-                       bio_put(bio);
-                       return -EIO;
-               }
+               if (ret)
+                       goto out_counter_dec;
                ASSERT(bioc->mirror_num == 1);
        } else {
                ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
                                      &map_length, &bioc, mirror_num);
-               if (ret) {
-                       btrfs_bio_counter_dec(fs_info);
-                       bio_put(bio);
-                       return -EIO;
-               }
+               if (ret)
+                       goto out_counter_dec;
                BUG_ON(mirror_num != bioc->mirror_num);
        }
 
        sector = bioc->stripes[bioc->mirror_num - 1].physical >> 9;
-       bio->bi_iter.bi_sector = sector;
        dev = bioc->stripes[bioc->mirror_num - 1].dev;
        btrfs_put_bioc(bioc);
+
        if (!dev || !dev->bdev ||
            !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
-               btrfs_bio_counter_dec(fs_info);
-               bio_put(bio);
-               return -EIO;
+               ret = -EIO;
+               goto out_counter_dec;
        }
-       bio_set_dev(bio, dev->bdev);
-       bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
-       bio_add_page(bio, page, length, pg_offset);
 
-       btrfsic_check_bio(bio);
-       if (submit_bio_wait(bio)) {
+       bio_init(&bio, dev->bdev, &bvec, 1, REQ_OP_WRITE | REQ_SYNC);
+       bio.bi_iter.bi_sector = sector;
+       __bio_add_page(&bio, page, length, pg_offset);
+
+       btrfsic_check_bio(&bio);
+       ret = submit_bio_wait(&bio);
+       if (ret) {
                /* try to remap that extent elsewhere? */
-               btrfs_bio_counter_dec(fs_info);
-               bio_put(bio);
                btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
-               return -EIO;
+               goto out_bio_uninit;
        }
 
        btrfs_info_rl_in_rcu(fs_info,
                "read error corrected: ino %llu off %llu (dev %s sector %llu)",
                                  ino, start,
                                  rcu_str_deref(dev->name), sector);
+       ret = 0;
+
+out_bio_uninit:
+       bio_uninit(&bio);
+out_counter_dec:
        btrfs_bio_counter_dec(fs_info);
-       bio_put(bio);
-       return 0;
+       return ret;
 }
 
 int btrfs_repair_eb_io_failure(const struct extent_buffer *eb, int mirror_num)