FAILED: patch "[PATCH] btrfs: zoned: activate metadata block group on write time" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 13bb483d32abb6f8ebd40141d87eb68f11cc2dd2
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023091640-upstroke-gopher-c666@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

13bb483d32ab ("btrfs: zoned: activate metadata block group on write time") 0356ad41e0dd ("btrfs: zoned: defer advancing meta write pointer")
2ad8c0510a96 ("btrfs: zoned: return int from btrfs_check_meta_write_pointer") 7db94301a980 ("btrfs: zoned: introduce block group context to btrfs_eb_write_context") 861093eff4f0 ("btrfs: introduce struct to consolidate extent buffer write context") 71df088c1cc0 ("btrfs: defer splitting of ordered extents until I/O completion") a6f3e205e491 ("btrfs: move split_extent_map to extent_map.c")
cbfce4c7fbde ("btrfs: optimize the logical to physical mapping for zoned writes") 5cfe76f846d5 ("btrfs: rename the bytenr field in struct btrfs_ordered_sum to logical") 6e4b2479ab38 ("btrfs: mark the len field in struct btrfs_ordered_sum as unsigned") 50b21d7a066f ("btrfs: submit a writeback bio per extent_buffer")
9fdd160160f0 ("btrfs: return bool from lock_extent_buffer_for_io")
adbe7e388e42 ("btrfs: use SECTOR_SHIFT to convert LBA to physical offset") 7edd339c8a41 ("btrfs: pass an ordered_extent to btrfs_extract_ordered_extent") 2e38a84bc6ab ("btrfs: simplify extent map splitting and rename split_zoned_em") 11d33ab6c1f3 ("btrfs: simplify splitting logic in btrfs_extract_ordered_extent") e44ca71cfe07 ("btrfs: move ordered_extent internal sanity checks into btrfs_split_ordered_extent") 2cef0c79bb81 ("btrfs: make btrfs_split_bio work on struct btrfs_bio")
ae42a154ca89 ("btrfs: pass a btrfs_bio to btrfs_submit_bio")
34f888ce3a35 ("btrfs: cleanup main loop in btrfs_encoded_read_regular_fill_pages")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 Mon Sep 17 00:00:00 2001
From: Naohiro Aota <[email protected]>
Date: Tue, 8 Aug 2023 01:12:37 +0900
Subject: [PATCH] btrfs: zoned: activate metadata block group on write time

In the current implementation, block groups are activated at reservation time to ensure that all reserved bytes can be written to an active metadata block group. However, this approach has proven to be less efficient, as it activates block groups more frequently than necessary, putting pressure on the active zone resource and leading to potential issues such as early ENOSPC or hung_task.

Another drawback of the current method is that it hampers metadata over-commit, and necessitates additional flush operations and block group allocations, resulting in decreased overall performance.

To address these issues, this commit introduces a write-time activation of metadata and system block group. This involves reserving at least one active block group specifically for a metadata and system block group.

Since metadata write-out is always allocated sequentially, when we need to write to a non-active block group, we can wait for the ongoing IOs to complete, activate a new block group, and then proceed with writing to the new block group.

index a127865f49f9..b0e432c30e1d 100644
@@ -4287,6 +4287,17 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
 	struct btrfs_caching_control *caching_ctl;
 	struct rb_node *n;
 
+	if (btrfs_is_zoned(info)) {
+		if (info->active_meta_bg) {
+			btrfs_put_block_group(info->active_meta_bg);
+			info->active_meta_bg = NULL;
+		}
+		if (info->active_system_bg) {
+			btrfs_put_block_group(info->active_system_bg);
+			info->active_system_bg = NULL;
+		}
+	}
+
 	write_lock(&info->block_group_cache_lock);
 	while (!list_empty(&info->caching_block_groups)) {
 		caching_ctl = list_entry(info->caching_block_groups.next,

index ef07c6c252d8..a523d64d5491 100644
@@ -770,6 +770,9 @@ struct btrfs_fs_info {
 	u64 data_reloc_bg;
 	struct mutex zoned_data_reloc_io_lock;
 
+	struct btrfs_block_group *active_meta_bg;
+	struct btrfs_block_group *active_system_bg;
+
 	u64 nr_global_roots;
 
 	spinlock_t zone_active_bgs_lock;