Re: [PATCH 1/2] btrfs: account partially completed discards

[Qu Wenruo <wqu@suse.com>]

在 2026/10/29 04:25, Luca Stefani via B4 Relay 写道:
> From: Luca Stefani <luca.stefani.ge1@gmail.com>
> 
> A discard can complete part of a range before a later chunk is interrupted
> or fails. btrfs_issue_discard() reports the bytes already discarded, but
> its callers only accumulate those bytes when the entire operation succeeds.
> 
> Link: https://lore.kernel.org/20261028-btrfs-fitrim-freezer-v1-1-0ad1d58aa94d@zliang.me/

I don't think this link tag adds any value.

This series is going a completely different, and more sane fix than that 
LLM generated one.

Otherwise looks good to me.

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu


> Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
> ---
>   fs/btrfs/extent-tree.c      | 5 ++---
>   fs/btrfs/free-space-cache.c | 5 ++---
>   2 files changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 9b0a5c6b96f3..242db255cf1c 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -1463,6 +1463,7 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
>   				continue;
>   
>   			ret = do_discard_extent(stripe, &bytes);
> +			discarded_bytes += bytes;
>   			if (ret) {
>   				/*
>   				 * Keep going if discard is not supported by the
> @@ -1471,8 +1472,6 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
>   				if (ret != -EOPNOTSUPP)
>   					break;
>   				ret = 0;
> -			} else {
> -				discarded_bytes += bytes;
>   			}
>   		}
>   		kfree(stripes);
> @@ -6703,6 +6702,7 @@ static int btrfs_trim_free_extents_throttle(struct btrfs_device *device,
>   
>   		ret = btrfs_issue_discard(device->bdev, start, len,
>   					  &bytes);
> +		*trimmed += bytes;
>   		if (!ret)
>   			btrfs_set_extent_bit(&device->alloc_state, start,
>   					     start + bytes - 1, CHUNK_TRIMMED, NULL);
> @@ -6712,7 +6712,6 @@ static int btrfs_trim_free_extents_throttle(struct btrfs_device *device,
>   			break;
>   
>   		start += len;
> -		*trimmed += bytes;
>   		trim_len += len;
>   		if (trim_len >= BTRFS_MAX_TRIM_LENGTH) {
>   			*ret_next_pos = start;
> diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
> index bff6e5b372d6..a85806bcf87a 100644
> --- a/fs/btrfs/free-space-cache.c
> +++ b/fs/btrfs/free-space-cache.c
> @@ -2415,10 +2415,9 @@ static int do_trimming(struct btrfs_block_group *block_group,
>   	spin_unlock(&space_info->lock);
>   
>   	ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed, false);
> -	if (!ret) {
> -		*total_trimmed += trimmed;
> +	*total_trimmed += trimmed;
> +	if (!ret)
>   		trim_state = BTRFS_TRIM_STATE_TRIMMED;
> -	}
>   
>   	if (reserved_start < start)
>   		__btrfs_add_free_space(block_group, reserved_start,
>