On 25.03.19 г. 14:31 ч., Nikolay Borisov wrote:
> We currently overload the pending_chunks list to handle updating
> btrfs_device->commit_bytes used. We don't actually care about
> the extent mapping or even the device mapping for the chunk - we
> just need the device, and we can end up processing it multiple
> times. The fs_devices->resized_list does more or less the same
> thing, but with the disk size. They are called consecutively
> during commit and have more or less the same purpose.
>
> We can combine the two lists into a single list that attaches
> to the transaction and contains a list of devices that need
> updating. Since we always add the device to a list when we
> change bytes_used or disk_total_size, there's no harm in
> copying both values at once.
>
> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
> ---
> fs/btrfs/dev-replace.c | 2 +-
> fs/btrfs/disk-io.c | 7 ++++
> fs/btrfs/transaction.c | 5 ++-
> fs/btrfs/transaction.h | 1 +
> fs/btrfs/volumes.c | 84 ++++++++++++++++++------------------------
> fs/btrfs/volumes.h | 13 ++-----
> 6 files changed, 51 insertions(+), 61 deletions(-)
>
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index ee193c5222b2..dba43ada41d1 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -662,7 +662,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
> btrfs_device_set_disk_total_bytes(tgt_device,
> src_device->disk_total_bytes);
> btrfs_device_set_bytes_used(tgt_device, src_device->bytes_used);
> - ASSERT(list_empty(&src_device->resized_list));
> + ASSERT(list_empty(&src_device->post_commit_list));
> tgt_device->commit_total_bytes = src_device->commit_total_bytes;
> tgt_device->commit_bytes_used = src_device->bytes_used;
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 82f6dfc132a7..80f0787eb278 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -4497,10 +4497,17 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction *cur_trans,
> void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
> struct btrfs_fs_info *fs_info)
> {
> + struct btrfs_device *dev, *tmp;
> +
> btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
> ASSERT(list_empty(&cur_trans->dirty_bgs));
> ASSERT(list_empty(&cur_trans->io_bgs));
>
> + list_for_each_entry_safe(dev, tmp, &cur_trans->dev_update_list,
> + post_commit_list) {
> + list_del_init(&dev->post_commit_list);
> + }
> +
> btrfs_destroy_delayed_refs(cur_trans, fs_info);
>
> cur_trans->state = TRANS_STATE_COMMIT_START;
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index f1732b77a379..4aa827a2e951 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -75,6 +75,7 @@ void btrfs_put_transaction(struct btrfs_transaction *transaction)
> btrfs_put_block_group_trimming(cache);
> btrfs_put_block_group(cache);
> }
> + WARN_ON(!list_empty(&transaction->dev_update_list));
> kfree(transaction);
> }
> }
> @@ -264,6 +265,7 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
>
> INIT_LIST_HEAD(&cur_trans->pending_snapshots);
> INIT_LIST_HEAD(&cur_trans->pending_chunks);
> + INIT_LIST_HEAD(&cur_trans->dev_update_list);
> INIT_LIST_HEAD(&cur_trans->switch_commits);
> INIT_LIST_HEAD(&cur_trans->dirty_bgs);
> INIT_LIST_HEAD(&cur_trans->io_bgs);
> @@ -2241,8 +2243,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
> memcpy(fs_info->super_for_commit, fs_info->super_copy,
> sizeof(*fs_info->super_copy));
>
> - btrfs_update_commit_device_size(fs_info);
> - btrfs_update_commit_device_bytes_used(cur_trans);
> + btrfs_commit_device_sizes(cur_trans);
>
> clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
> clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
> diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
> index b34678e7968e..2bd76f681520 100644
> --- a/fs/btrfs/transaction.h
> +++ b/fs/btrfs/transaction.h
> @@ -52,6 +52,7 @@ struct btrfs_transaction {
> wait_queue_head_t commit_wait;
> struct list_head pending_snapshots;
> struct list_head pending_chunks;
> + struct list_head dev_update_list;
> struct list_head switch_commits;
> struct list_head dirty_bgs;
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index db934ceae9c1..3f81380265e5 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -318,7 +318,6 @@ static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid,
> mutex_init(&fs_devs->device_list_mutex);
>
> INIT_LIST_HEAD(&fs_devs->devices);
> - INIT_LIST_HEAD(&fs_devs->resized_devices);
> INIT_LIST_HEAD(&fs_devs->alloc_list);
> INIT_LIST_HEAD(&fs_devs->fs_list);
> if (fsid)
> @@ -334,6 +333,7 @@ static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid,
>
> void btrfs_free_device(struct btrfs_device *device)
> {
> + WARN_ON(!list_empty(&device->post_commit_list));
> rcu_string_free(device->name);
> bio_put(device->flush_bio);
> kfree(device);
> @@ -402,7 +402,7 @@ static struct btrfs_device *__alloc_device(void)
>
> INIT_LIST_HEAD(&dev->dev_list);
> INIT_LIST_HEAD(&dev->dev_alloc_list);
> - INIT_LIST_HEAD(&dev->resized_list);
> + INIT_LIST_HEAD(&dev->post_commit_list);
>
> spin_lock_init(&dev->io_lock);
>
> @@ -2880,9 +2880,9 @@ int btrfs_grow_device(struct btrfs_trans_handle *trans,
> btrfs_device_set_total_bytes(device, new_size);
> btrfs_device_set_disk_total_bytes(device, new_size);
> btrfs_clear_space_info_full(device->fs_info);
> - if (list_empty(&device->resized_list))
> - list_add_tail(&device->resized_list,
> - &fs_devices->resized_devices);
> + if (list_empty(&device->post_commit_list))
> + list_add_tail(&device->post_commit_list,
> + &trans->transaction->dev_update_list);
> mutex_unlock(&fs_info->chunk_mutex);
>
> return btrfs_update_device(trans, device);
> @@ -4871,9 +4871,9 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
> }
>
> btrfs_device_set_disk_total_bytes(device, new_size);
> - if (list_empty(&device->resized_list))
> - list_add_tail(&device->resized_list,
> - &fs_info->fs_devices->resized_devices);
> + if (list_empty(&device->post_commit_list))
> + list_add_tail(&device->post_commit_list,
> + &trans->transaction->dev_update_list);
>
> WARN_ON(diff > old_total);
> btrfs_set_super_total_bytes(super_copy,
> @@ -5222,9 +5222,14 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
> if (ret)
> goto error_del_extent;
>
> - for (i = 0; i < map->num_stripes; i++)
> - btrfs_device_set_bytes_used(map->stripes[i].dev,
> - map->stripes[i].dev->bytes_used + stripe_size);
> + for (i = 0; i < map->num_stripes; i++) {
> + struct btrfs_device *dev = map->stripes[i].dev;
> +
> + btrfs_device_set_bytes_used(dev, dev->bytes_used + stripe_size);
> + if (list_empty(&dev->post_commit_list))
> + list_add_tail(&dev->post_commit_list,
> + &trans->transaction->dev_update_list);
> + }
>
> atomic64_sub(stripe_size * map->num_stripes, &info->free_chunk_space);
>
> @@ -7674,51 +7679,34 @@ void btrfs_scratch_superblocks(struct block_device *bdev, const char *device_pat
> }
>
> /*
> - * Update the size of all devices, which is used for writing out the
> - * super blocks.
> + * Update the size and bytes used for each device where it changed.
> + * This is delayed since we would otherwise get errors while writing
> + * out the superblocks.
> + *
> + * Must be invoked during transaction commit.
> */
> -void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
> +void btrfs_commit_device_sizes(struct btrfs_transaction *trans)
> {
> - struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
> struct btrfs_device *curr, *next;
>
> - if (list_empty(&fs_devices->resized_devices))
> - return;
> -
> - mutex_lock(&fs_devices->device_list_mutex);
> - mutex_lock(&fs_info->chunk_mutex);
> - list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
> - resized_list) {
> - list_del_init(&curr->resized_list);
> - curr->commit_total_bytes = curr->disk_total_bytes;
> - }
> - mutex_unlock(&fs_info->chunk_mutex);
> - mutex_unlock(&fs_devices->device_list_mutex);
> -}
> -
> -/* Must be invoked during the transaction commit */
> -void btrfs_update_commit_device_bytes_used(struct btrfs_transaction *trans)
> -{
> - struct btrfs_fs_info *fs_info = trans->fs_info;
> - struct extent_map *em;
> - struct map_lookup *map;
> - struct btrfs_device *dev;
> - int i;
> + ASSERT(trans->state != TRANS_STATE_COMMIT_DOING);
I changed this to an assert form a BUG_ON but it also needs to
adjustment of the condition, it should be:
ASSERT(trans->state == TRANS_STATE_COMMIT_DOING);
>
> - if (list_empty(&trans->pending_chunks))
> + if (list_empty(&trans->dev_update_list))
> return;
>
> - /* In order to kick the device replace finish process */
> - mutex_lock(&fs_info->chunk_mutex);
> - list_for_each_entry(em, &trans->pending_chunks, list) {
> - map = em->map_lookup;
> -
> - for (i = 0; i < map->num_stripes; i++) {
> - dev = map->stripes[i].dev;
> - dev->commit_bytes_used = dev->bytes_used;
> - }
> + /*
> + * We don't need the device_list_mutex here. This list is owned
> + * by the transaction and the transaction must complete before
> + * the device is released.
> + */
> + mutex_lock(&trans->fs_info->chunk_mutex);
> + list_for_each_entry_safe(curr, next, &trans->dev_update_list,
> + post_commit_list) {
> + list_del_init(&curr->post_commit_list);
> + curr->commit_total_bytes = curr->disk_total_bytes;
> + curr->commit_bytes_used = curr->bytes_used;
> }
> - mutex_unlock(&fs_info->chunk_mutex);
> + mutex_unlock(&trans->fs_info->chunk_mutex);
> }
>
> void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index 3ad9d58d1b66..a0f09aad3770 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -45,6 +45,7 @@ struct btrfs_pending_bios {
> struct btrfs_device {
> struct list_head dev_list;
> struct list_head dev_alloc_list;
> + struct list_head post_commit_list; /* chunk mutex */
> struct btrfs_fs_devices *fs_devices;
> struct btrfs_fs_info *fs_info;
>
> @@ -102,18 +103,12 @@ struct btrfs_device {
> * size of the device on the current transaction
> *
> * This variant is update when committing the transaction,
> - * and protected by device_list_mutex
> + * and protected by chunk mutex
> */
> u64 commit_total_bytes;
>
> /* bytes used on the current transaction */
> u64 commit_bytes_used;
> - /*
> - * used to manage the device which is resized
> - *
> - * It is protected by chunk_lock.
> - */
> - struct list_head resized_list;
>
> /* for sending down flush barriers */
> struct bio *flush_bio;
> @@ -235,7 +230,6 @@ struct btrfs_fs_devices {
> struct mutex device_list_mutex;
> struct list_head devices;
>
> - struct list_head resized_devices;
> /* devices not currently being allocated */
> struct list_head alloc_list;
>
> @@ -558,8 +552,7 @@ static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags)
>
> const char *get_raid_name(enum btrfs_raid_types type);
>
> -void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info);
> -void btrfs_update_commit_device_bytes_used(struct btrfs_transaction *trans);
> +void btrfs_commit_device_sizes(struct btrfs_transaction *trans);
>
> struct list_head *btrfs_get_fs_uuids(void);
> void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info);
>
