On Sat, Apr 02, 2016 at 09:30:48AM +0800, Anand Jain wrote:
> Hot replace / auto replace is important volume manager feature
> and is critical to the data center operations, so that the degraded
> volume can be brought back to a healthy state at the earliest and
> without manual intervention.
>
> This modifies the existing replace code to suite the need of auto
> replace, in the long run I hope both the codes to be merged.
>
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
> Tested-by: Austin S. Hemmelgarn <ahferroin7@xxxxxxxxx>
> ---
> fs/btrfs/dev-replace.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> fs/btrfs/dev-replace.h | 1 +
> 2 files changed, 44 insertions(+)
>
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index 2b926867d136..ceab4c51db32 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -957,3 +957,46 @@ void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info)
> &fs_info->fs_state));
> }
> }
> +
> +int btrfs_auto_replace_start(struct btrfs_root *root,
> + struct btrfs_device *src_device)
> +{
> + int ret;
> + char *tgt_path;
> + char *src_path;
> + struct btrfs_fs_info *fs_info = root->fs_info;
> +
> + if (fs_info->sb->s_flags & MS_RDONLY)
> + return -EROFS;
> +
> + btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
> + if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
> + btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
> + return -EBUSY;
> + }
> + btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
> +
> + if (btrfs_get_spare_device(&tgt_path)) {
> + btrfs_err(root->fs_info,
> + "No spare device found/configured in the kernel");
> + return -EINVAL;
> + }
> +
> + rcu_read_lock();
> + src_path = kstrdup(rcu_str_deref(src_device->name), GFP_ATOMIC);
> + rcu_read_unlock();
> + if (!src_path) {
> + kfree(tgt_path);
> + return -ENOMEM;
> + }
> + ret = btrfs_dev_replace_start(root, tgt_path,
> + src_device->devid, src_path,
> + BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID);
> + if (ret)
> + btrfs_put_spare_device(tgt_path);
> +
> + kfree(tgt_path);
> + kfree(src_path);
> +
> + return 0;
> +}
Without of fs_info->mutually_exclusive_operation_running flag set in
btrfs_auto_replace_start(), device add/remove/balance etc. can be
started in parralel with autoreplace. Should this scenarios be permitted?
> diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h
> index e922b42d91df..b918b9d6e5df 100644
> --- a/fs/btrfs/dev-replace.h
> +++ b/fs/btrfs/dev-replace.h
> @@ -46,4 +46,5 @@ static inline void btrfs_dev_replace_stats_inc(atomic64_t *stat_value)
> {
> atomic64_inc(stat_value);
> }
> +int btrfs_auto_replace_start(struct btrfs_root *root, struct btrfs_device *src_device);
> #endif
> --
> 2.7.0
--
Yauhen Kharuzhy
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