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Message-ID: <CAL3q7H5yRnxZQzvSoD0H6fWz2dmToxeE7v1v7gFt1Vstc6Q33w@mail.gmail.com>
Date: Thu, 23 Nov 2023 16:33:02 +0000
From: Filipe Manana <fdmanana@...nel.org>
To: Johannes Thumshirn <johannes.thumshirn@....com>
Cc: Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>, linux-btrfs@...r.kernel.org,
linux-kernel@...r.kernel.org, Christoph Hellwig <hch@....de>,
Naohiro Aota <Naohiro.Aota@....com>
Subject: Re: [PATCH v2 5/5] btrfs: reflow btrfs_free_tree_block
On Thu, Nov 23, 2023 at 3:48 PM Johannes Thumshirn
<johannes.thumshirn@....com> wrote:
>
> Reflow btrfs_free_tree_block() so that there is one level of indentation
> needed.
>
> This patch has no functional changes.
>
> Reviewed-by: Christoph Hellwig <hch@....de>
> Reviewed-by: Josef Bacik <josef@...icpanda.com>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@....com>
> ---
> fs/btrfs/extent-tree.c | 97 +++++++++++++++++++++++++-------------------------
> 1 file changed, 49 insertions(+), 48 deletions(-)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 4044102271e9..093aaf7aeb3a 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -3426,6 +3426,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
> {
> struct btrfs_fs_info *fs_info = trans->fs_info;
> struct btrfs_ref generic_ref = { 0 };
> + struct btrfs_block_group *cache;
While at it, can we rename 'cache' to something like 'bg'?
The cache name comes from the times where the structure was named
btrfs_block_group_cache, and having it named cache is always
confusing.
Nevertheless, the change looks fine to me.
Reviewed-by: Filipe Manana <fdmanana@...e.com>
> int ret;
>
> btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
> @@ -3439,64 +3440,64 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
> BUG_ON(ret); /* -ENOMEM */
> }
>
> - if (last_ref && btrfs_header_generation(buf) == trans->transid) {
> - struct btrfs_block_group *cache;
> - bool must_pin = false;
> -
> - if (root_id != BTRFS_TREE_LOG_OBJECTID) {
> - ret = check_ref_cleanup(trans, buf->start);
> - if (!ret)
> - goto out;
> - }
> + if (!last_ref)
> + return;
>
> - cache = btrfs_lookup_block_group(fs_info, buf->start);
> + if (btrfs_header_generation(buf) != trans->transid)
> + goto out;
>
> - if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
> - pin_down_extent(trans, cache, buf->start, buf->len, 1);
> - btrfs_put_block_group(cache);
> + if (root_id != BTRFS_TREE_LOG_OBJECTID) {
> + ret = check_ref_cleanup(trans, buf->start);
> + if (!ret)
> goto out;
> - }
> + }
>
> - /*
> - * If there are tree mod log users we may have recorded mod log
> - * operations for this node. If we re-allocate this node we
> - * could replay operations on this node that happened when it
> - * existed in a completely different root. For example if it
> - * was part of root A, then was reallocated to root B, and we
> - * are doing a btrfs_old_search_slot(root b), we could replay
> - * operations that happened when the block was part of root A,
> - * giving us an inconsistent view of the btree.
> - *
> - * We are safe from races here because at this point no other
> - * node or root points to this extent buffer, so if after this
> - * check a new tree mod log user joins we will not have an
> - * existing log of operations on this node that we have to
> - * contend with.
> - */
> - if (test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags))
> - must_pin = true;
> + cache = btrfs_lookup_block_group(fs_info, buf->start);
>
> - if (must_pin || btrfs_is_zoned(fs_info)) {
> - pin_down_extent(trans, cache, buf->start, buf->len, 1);
> - btrfs_put_block_group(cache);
> - goto out;
> - }
> + if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
> + pin_down_extent(trans, cache, buf->start, buf->len, 1);
> + btrfs_put_block_group(cache);
> + goto out;
> + }
>
> - WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
> + /*
> + * If there are tree mod log users we may have recorded mod log
> + * operations for this node. If we re-allocate this node we
> + * could replay operations on this node that happened when it
> + * existed in a completely different root. For example if it
> + * was part of root A, then was reallocated to root B, and we
> + * are doing a btrfs_old_search_slot(root b), we could replay
> + * operations that happened when the block was part of root A,
> + * giving us an inconsistent view of the btree.
> + *
> + * We are safe from races here because at this point no other
> + * node or root points to this extent buffer, so if after this
> + * check a new tree mod log user joins we will not have an
> + * existing log of operations on this node that we have to
> + * contend with.
> + */
>
> - btrfs_add_free_space(cache, buf->start, buf->len);
> - btrfs_free_reserved_bytes(cache, buf->len, 0);
> + if (test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)
> + || btrfs_is_zoned(fs_info)) {
> + pin_down_extent(trans, cache, buf->start, buf->len, 1);
> btrfs_put_block_group(cache);
> - trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
> + goto out;
> }
> +
> + WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
> +
> + btrfs_add_free_space(cache, buf->start, buf->len);
> + btrfs_free_reserved_bytes(cache, buf->len, 0);
> + btrfs_put_block_group(cache);
> + trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
> +
> out:
> - if (last_ref) {
> - /*
> - * Deleting the buffer, clear the corrupt flag since it doesn't
> - * matter anymore.
> - */
> - clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
> - }
> +
> + /*
> + * Deleting the buffer, clear the corrupt flag since it doesn't
> + * matter anymore.
> + */
> + clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
> }
>
> /* Can return -ENOMEM */
>
> --
> 2.41.0
>
>
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