On Tuesday, June 21, 2011 01:49:19 PM Li Zefan wrote:
> We're taking a free space extent out of the free space cache, trimming
> it and then putting it back into the cache.
>
sorry for the late reply, I can hardly to find time look at this.
> However for an extent that is smaller than the specified minimum length,
> it's taken out but won't be put back, which causes space leak.
yes, you are correct, and the fix looks good to me, Thanks
>
> Signed-off-by: Li Zefan <l...@cn.fujitsu.com>
> ---
>
> Unfortunately I have no trim-able device to test the patch.
>
> ---
> fs/btrfs/free-space-cache.c | 34 +++++++++++++++++-----------------
> 1 files changed, 17 insertions(+), 17 deletions(-)
>
> diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
> index 9f985a4..292c0d9 100644
> --- a/fs/btrfs/free-space-cache.c
> +++ b/fs/btrfs/free-space-cache.c
> @@ -2460,6 +2460,7 @@ int btrfs_trim_block_group(struct
> btrfs_block_group_cache *block_group,
> u64 bytes = 0;
> u64 actually_trimmed;
> int ret = 0;
> + int update_ret;
>
> *trimmed = 0;
>
> @@ -2483,6 +2484,7 @@ int btrfs_trim_block_group(struct
> btrfs_block_group_cache *block_group,
> }
>
> if (entry->bitmap) {
> + bytes = 0;
> ret = search_bitmap(ctl, entry, &start, &bytes);
> if (!ret) {
> if (start >= end) {
> @@ -2490,6 +2492,8 @@ int btrfs_trim_block_group(struct
> btrfs_block_group_cache *block_group,
> break;
> }
> bytes = min(bytes, end - start);
> + if (bytes < minlen)
> + goto next;
> bitmap_clear_bits(ctl, entry, start, bytes);
> if (entry->bytes == 0)
> free_bitmap(ctl, entry);
> @@ -2503,33 +2507,29 @@ int btrfs_trim_block_group(struct
> btrfs_block_group_cache *block_group,
> } else {
> start = entry->offset;
> bytes = min(entry->bytes, end - start);
> + if (bytes < minlen)
> + goto next;
> unlink_free_space(ctl, entry);
> kmem_cache_free(btrfs_free_space_cachep, entry);
> }
>
> spin_unlock(&ctl->tree_lock);
>
> - if (bytes >= minlen) {
> - int update_ret;
> - update_ret = btrfs_update_reserved_bytes(block_group,
> - bytes, 1, 1);
> + update_ret = btrfs_update_reserved_bytes(block_group,
> + bytes, 1, 1);
>
> - ret = btrfs_error_discard_extent(fs_info->extent_root,
> - start,
> - bytes,
> - &actually_trimmed);
> + ret = btrfs_error_discard_extent(fs_info->extent_root, start,
> + bytes, &actually_trimmed);
>
> - btrfs_add_free_space(block_group, start, bytes);
> - if (!update_ret)
> - btrfs_update_reserved_bytes(block_group,
> - bytes, 0, 1);
> + btrfs_add_free_space(block_group, start, bytes);
> + if (!update_ret)
> + btrfs_update_reserved_bytes(block_group, bytes, 0, 1);
>
> - if (ret)
> - break;
> - *trimmed += actually_trimmed;
> - }
> + if (ret)
> + break;
> + *trimmed += actually_trimmed;
> +next:
> start += bytes;
> - bytes = 0;
>
> if (fatal_signal_pending(current)) {
> ret = -ERESTARTSYS;
>
--
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