On 11.04.19 г. 12:57 ч., Qu Wenruo wrote:
> [BUG]
> Since commit "btrfs-progs: disk-io: Flush to ensure super block write is
> FUA" mkfs-tests/017 will fail like:
>
> ====== RUN MUSTFAIL /home/adam/btrfs-progs/mkfs.btrfs -K -f /dev/mapper/btrfs-progs-thin-vol
> ERROR: failed to write super block for devid 1: flush error: Input/output error
> disk-io.c:1810: write_all_supers: BUG_ON `ret` triggered, value -5
> /home/adam/btrfs-progs/mkfs.btrfs(+0x1e5c1)[0x557a2c83e5c1]
> /home/adam/btrfs-progs/mkfs.btrfs(+0x1e65f)[0x557a2c83e65f]
> /home/adam/btrfs-progs/mkfs.btrfs(write_all_supers+0x1ce)[0x557a2c843a8a]
> /home/adam/btrfs-progs/mkfs.btrfs(write_ctree_super+0x12d)[0x557a2c843be2]
> /home/adam/btrfs-progs/mkfs.btrfs(btrfs_commit_transaction+0x250)[0x557a2c887c56]
> /home/adam/btrfs-progs/mkfs.btrfs(+0xc0b1)[0x557a2c82c0b1]
> /home/adam/btrfs-progs/mkfs.btrfs(main+0x1049)[0x557a2c82e929]
> /usr/lib/libc.so.6(__libc_start_main+0xf3)[0x7f6689e99223]
> /home/adam/btrfs-progs/mkfs.btrfs(_start+0x2e)[0x557a2c82b86e]
> failed (expected): /home/adam/btrfs-progs/mkfs.btrfs -K -f /dev/mapper/btrfs-progs-thin-vol
>
> [CAUSE]
> Just one BUG_ON() in write_all_supers().
>
> [FIX]
> Just remove the BUG_ON(). Callers of write_all_supers() are already
> checking the return value.
>
> Also since write_all_supers() can return error, make write_ctree_super()
> callers, btrfs_commit_transaction() and close_ctree_fs_info() to
> handle the error correctly.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> ---
> Changelog:
> v2:
> - Make write_ctree_super() callers to handle the error properly
> ---
> disk-io.c | 16 ++++++++++------
> transaction.c | 2 +-
> 2 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/disk-io.c b/disk-io.c
> index 10550151c5bb..a3aa8b29f2a3 100644
> --- a/disk-io.c
> +++ b/disk-io.c
> @@ -1807,7 +1807,8 @@ int write_all_supers(struct btrfs_fs_info *fs_info)
> btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
>
> ret = write_dev_supers(fs_info, sb, dev);
> - BUG_ON(ret);
> + if (ret < 0)
> + return ret;
> }
> return 0;
> }
> @@ -1863,17 +1864,20 @@ int close_ctree_fs_info(struct btrfs_fs_info *fs_info)
> BUG_ON(ret);
> ret = __commit_transaction(trans, root);
> BUG_ON(ret);
> - write_ctree_super(trans);
> + ret = write_ctree_super(trans);
> kfree(trans);
if (ret) {
err = ret;
goto skip_commit
}
> }
>
> if (fs_info->finalize_on_close) {
> btrfs_set_super_magic(fs_info->super_copy, BTRFS_MAGIC);
> root->fs_info->finalize_on_close = 0;
> - ret = write_all_supers(fs_info);
> - if (ret)
> - fprintf(stderr,
> - "failed to write new super block err %d\n", ret);
> + if (!ret) {
> + ret = write_all_supers(fs_info);
> + if (ret)
> + fprintf(stderr,
> + "failed to write new super block err %d\n",
> + ret);
> + }
And you won't have to touch this code at all.
> }
>
> skip_commit:
> diff --git a/transaction.c b/transaction.c
> index e756db332fec..3a63988b0969 100644
> --- a/transaction.c
> +++ b/transaction.c
> @@ -197,7 +197,7 @@ commit_tree:
> __commit_transaction(trans, root);
> if (ret < 0)
> goto out;
> - write_ctree_super(trans);
> + ret = write_ctree_super(trans);
> btrfs_finish_extent_commit(trans, fs_info->extent_root,
> &fs_info->pinned_extents);
> kfree(trans);
>
