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 stable@vger.kernel.org.

Possible dependencies:

85e79ec7b78f ("btrfs: zoned: enable metadata over-commit for non-ZNS setup") c52cc7b7acfb ("btrfs: add a BTRFS_FS_NEED_TRANS_COMMIT flag") 7966a6b5959b ("btrfs: move fs_info::flags enum to fs.h") fc97a410bd78 ("btrfs: move mount option definitions to fs.h") 0d3a9cf8c306 ("btrfs: convert incompat and compat flag test helpers to macros") ec8eb376e271 ("btrfs: move BTRFS_FS_STATE* definitions and helpers to fs.h") 9b569ea0be6f ("btrfs: move the printk helpers out of ctree.h") e118578a8df7 ("btrfs: move assert helpers out of ctree.h") c7f13d428ea1 ("btrfs: move fs wide helpers out of ctree.h") 63a7cb130718 ("btrfs: auto enable discard=async when possible") f1e5c6185ca1 ("btrfs: move flush related definitions to space-info.h") 4300c58f8090 ("btrfs: move btrfs on-disk definitions out of ctree.h") d60d956eb41f ("btrfs: remove unused set/clear_pending_info helpers")

thanks,

greg k-h

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

From 85e79ec7b78f863178ca488fd8cb5b3de6347756 Mon Sep 17 00:00:00 2001 From: Naohiro Aota naohiro.aota@wdc.com Date: Tue, 10 Jan 2023 15:04:32 +0900 Subject: [PATCH] btrfs: zoned: enable metadata over-commit for non-ZNS setup

The commit 79417d040f4f ("btrfs: zoned: disable metadata overcommit for zoned") disabled the metadata over-commit to track active zones properly.

However, it also introduced a heavy overhead by allocating new metadata block groups and/or flushing dirty buffers to release the space reservations. Specifically, a workload (write only without any sync operations) worsen its performance from 343.77 MB/sec (v5.19) to 182.89 MB/sec (v6.0).

The performance is still bad on current misc-next which is 187.95 MB/sec. And, with this patch applied, it improves back to 326.70 MB/sec (+73.82%).

This patch introduces a new fs_info->flag BTRFS_FS_NO_OVERCOMMIT to indicate it needs to disable the metadata over-commit. The flag is enabled when a device with max active zones limit is loaded into a file-system.

Fixes: 79417d040f4f ("btrfs: zoned: disable metadata overcommit for zoned") CC: stable@vger.kernel.org # 6.0+ Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Signed-off-by: David Sterba dsterba@suse.com

diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h index a749367e5ae2..37b86acfcbcf 100644 --- a/fs/btrfs/fs.h +++ b/fs/btrfs/fs.h @@ -119,6 +119,12 @@ enum { /* Indicate that we want to commit the transaction. */ BTRFS_FS_NEED_TRANS_COMMIT,

+ /* + * Indicate metadata over-commit is disabled. This is set when active + * zone tracking is needed. + */ + BTRFS_FS_NO_OVERCOMMIT, + #if BITS_PER_LONG == 32 /* Indicate if we have error/warn message printed on 32bit systems */ BTRFS_FS_32BIT_ERROR, diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index d28ee4e36f3d..69c09508afb5 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -407,7 +407,8 @@ int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, return 0;

used = btrfs_space_info_used(space_info, true); - if (btrfs_is_zoned(fs_info) && (space_info->flags & BTRFS_BLOCK_GROUP_METADATA)) + if (test_bit(BTRFS_FS_NO_OVERCOMMIT, &fs_info->flags) && + (space_info->flags & BTRFS_BLOCK_GROUP_METADATA)) avail = 0; else avail = calc_available_free_space(fs_info, space_info, flush); diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c index a759668477bb..1f503e8e42d4 100644 --- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -539,6 +539,8 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache) } atomic_set(&zone_info->active_zones_left, max_active_zones - nactive); + /* Overcommit does not work well with active zone tacking. */ + set_bit(BTRFS_FS_NO_OVERCOMMIT, &fs_info->flags); }

/* Validate superblock log */