From ae23fee41b36a39f8e163580fe273ca3f88f2413 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Thu, 8 Jan 2026 14:31:03 +1030 Subject: [PATCH] btrfs: remove experimental offload csum mode The offload csum mode was introduced to allow developers to compare the performance of generating checksum for data writes at different timings: - During btrfs_submit_chunk() This is the most common one, if any of the following condition is met we go this path: * The csum is fast For now it's CRC32C and xxhash. * It's a synchronous write * Zoned - Delay the checksum generation to a workqueue However since commit dd57c78aec39 ("btrfs: introduce btrfs_bio::async_csum") we no longer need to bother any of them. As if it's an experimental build, async checksum generation at the background will be faster anyway. And if not an experimental build, we won't even have the offload csum mode support. Considering the async csum will be the new default, let's remove the offload csum mode code. There will be no impact to end users, and offload csum mode is still under experimental features. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/Kconfig | 3 --- fs/btrfs/bio.c | 5 ----- fs/btrfs/sysfs.c | 44 -------------------------------------------- fs/btrfs/volumes.h | 22 ---------------------- 4 files changed, 74 deletions(-) diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig index d88eb836a1931..423122786a934 100644 --- a/fs/btrfs/Kconfig +++ b/fs/btrfs/Kconfig @@ -104,9 +104,6 @@ config BTRFS_EXPERIMENTAL - send stream protocol v3 - fs-verity support - - checksum offload mode - sysfs knob to affect when checksums are - calculated (at IO time, or in a thread) - - raid-stripe-tree - additional mapping of extents to devices to support RAID1* profiles on zoned devices, RAID56 not yet supported diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c index a12446aa0fbf7..d46f399964690 100644 --- a/fs/btrfs/bio.c +++ b/fs/btrfs/bio.c @@ -665,11 +665,6 @@ static bool should_async_write(struct btrfs_bio *bbio) bool auto_csum_mode = true; #ifdef CONFIG_BTRFS_EXPERIMENTAL - struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; - enum btrfs_offload_csum_mode csum_mode = READ_ONCE(fs_devices->offload_csum_mode); - - if (csum_mode == BTRFS_OFFLOAD_CSUM_FORCE_ON) - return true; /* * Write bios will calculate checksum and submit bio at the same time. * Unless explicitly required don't offload serial csum calculate and bio diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index f0974f4c0ae45..ebd6d1d6778ba 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -1538,47 +1538,6 @@ static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj, BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show, btrfs_bg_reclaim_threshold_store); -#ifdef CONFIG_BTRFS_EXPERIMENTAL -static ssize_t btrfs_offload_csum_show(struct kobject *kobj, - struct kobj_attribute *a, char *buf) -{ - struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); - - switch (READ_ONCE(fs_devices->offload_csum_mode)) { - case BTRFS_OFFLOAD_CSUM_AUTO: - return sysfs_emit(buf, "auto\n"); - case BTRFS_OFFLOAD_CSUM_FORCE_ON: - return sysfs_emit(buf, "1\n"); - case BTRFS_OFFLOAD_CSUM_FORCE_OFF: - return sysfs_emit(buf, "0\n"); - default: - WARN_ON(1); - return -EINVAL; - } -} - -static ssize_t btrfs_offload_csum_store(struct kobject *kobj, - struct kobj_attribute *a, const char *buf, - size_t len) -{ - struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); - int ret; - bool val; - - ret = kstrtobool(buf, &val); - if (ret == 0) - WRITE_ONCE(fs_devices->offload_csum_mode, - val ? BTRFS_OFFLOAD_CSUM_FORCE_ON : BTRFS_OFFLOAD_CSUM_FORCE_OFF); - else if (ret == -EINVAL && sysfs_streq(buf, "auto")) - WRITE_ONCE(fs_devices->offload_csum_mode, BTRFS_OFFLOAD_CSUM_AUTO); - else - return -EINVAL; - - return len; -} -BTRFS_ATTR_RW(, offload_csum, btrfs_offload_csum_show, btrfs_offload_csum_store); -#endif - /* * Per-filesystem information and stats. * @@ -1598,9 +1557,6 @@ static const struct attribute *btrfs_attrs[] = { BTRFS_ATTR_PTR(, bg_reclaim_threshold), BTRFS_ATTR_PTR(, commit_stats), BTRFS_ATTR_PTR(, temp_fsid), -#ifdef CONFIG_BTRFS_EXPERIMENTAL - BTRFS_ATTR_PTR(, offload_csum), -#endif NULL, }; diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index f20abeb16bce7..262526657cdf7 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -321,25 +321,6 @@ enum btrfs_read_policy { BTRFS_NR_READ_POLICY, }; -#ifdef CONFIG_BTRFS_EXPERIMENTAL -/* - * Checksum mode - offload it to workqueues or do it synchronously in - * btrfs_submit_chunk(). - */ -enum btrfs_offload_csum_mode { - /* - * Choose offloading checksum or do it synchronously automatically. - * Do it synchronously if the checksum is fast, or offload to workqueues - * otherwise. - */ - BTRFS_OFFLOAD_CSUM_AUTO, - /* Always offload checksum to workqueues. */ - BTRFS_OFFLOAD_CSUM_FORCE_ON, - /* Never offload checksum to workqueues. */ - BTRFS_OFFLOAD_CSUM_FORCE_OFF, -}; -#endif - struct btrfs_fs_devices { u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */ @@ -466,9 +447,6 @@ struct btrfs_fs_devices { /* Device to be used for reading in case of RAID1. */ u64 read_devid; - - /* Checksum mode - offload it or do it synchronously. */ - enum btrfs_offload_csum_mode offload_csum_mode; #endif }; -- 2.47.3