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Diffstat (limited to 'fs/btrfs/discard.c')
| -rw-r--r-- | fs/btrfs/discard.c | 702 |
1 files changed, 702 insertions, 0 deletions
diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c new file mode 100644 index 000000000000..5615320fa659 --- /dev/null +++ b/fs/btrfs/discard.c @@ -0,0 +1,702 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/ktime.h> +#include <linux/list.h> +#include <linux/math64.h> +#include <linux/sizes.h> +#include <linux/workqueue.h> +#include "ctree.h" +#include "block-group.h" +#include "discard.h" +#include "free-space-cache.h" + +/* + * This contains the logic to handle async discard. + * + * Async discard manages trimming of free space outside of transaction commit. + * Discarding is done by managing the block_groups on a LRU list based on free + * space recency. Two passes are used to first prioritize discarding extents + * and then allow for trimming in the bitmap the best opportunity to coalesce. + * The block_groups are maintained on multiple lists to allow for multiple + * passes with different discard filter requirements. A delayed work item is + * used to manage discarding with timeout determined by a max of the delay + * incurred by the iops rate limit, the byte rate limit, and the max delay of + * BTRFS_DISCARD_MAX_DELAY. + * + * Note, this only keeps track of block_groups that are explicitly for data. + * Mixed block_groups are not supported. + * + * The first list is special to manage discarding of fully free block groups. + * This is necessary because we issue a final trim for a full free block group + * after forgetting it. When a block group becomes unused, instead of directly + * being added to the unused_bgs list, we add it to this first list. Then + * from there, if it becomes fully discarded, we place it onto the unused_bgs + * list. + * + * The in-memory free space cache serves as the backing state for discard. + * Consequently this means there is no persistence. We opt to load all the + * block groups in as not discarded, so the mount case degenerates to the + * crashing case. + * + * As the free space cache uses bitmaps, there exists a tradeoff between + * ease/efficiency for find_free_extent() and the accuracy of discard state. + * Here we opt to let untrimmed regions merge with everything while only letting + * trimmed regions merge with other trimmed regions. This can cause + * overtrimming, but the coalescing benefit seems to be worth it. Additionally, + * bitmap state is tracked as a whole. If we're able to fully trim a bitmap, + * the trimmed flag is set on the bitmap. Otherwise, if an allocation comes in, + * this resets the state and we will retry trimming the whole bitmap. This is a + * tradeoff between discard state accuracy and the cost of accounting. + */ + +/* This is an initial delay to give some chance for block reuse */ +#define BTRFS_DISCARD_DELAY (120ULL * NSEC_PER_SEC) +#define BTRFS_DISCARD_UNUSED_DELAY (10ULL * NSEC_PER_SEC) + +/* Target completion latency of discarding all discardable extents */ +#define BTRFS_DISCARD_TARGET_MSEC (6 * 60 * 60UL * MSEC_PER_SEC) +#define BTRFS_DISCARD_MIN_DELAY_MSEC (1UL) +#define BTRFS_DISCARD_MAX_DELAY_MSEC (1000UL) +#define BTRFS_DISCARD_MAX_IOPS (10U) + +/* Montonically decreasing minimum length filters after index 0 */ +static int discard_minlen[BTRFS_NR_DISCARD_LISTS] = { + 0, + BTRFS_ASYNC_DISCARD_MAX_FILTER, + BTRFS_ASYNC_DISCARD_MIN_FILTER +}; + +static struct list_head *get_discard_list(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + return &discard_ctl->discard_list[block_group->discard_index]; +} + +static void __add_to_discard_list(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + if (!btrfs_run_discard_work(discard_ctl)) + return; + + if (list_empty(&block_group->discard_list) || + block_group->discard_index == BTRFS_DISCARD_INDEX_UNUSED) { + if (block_group->discard_index == BTRFS_DISCARD_INDEX_UNUSED) + block_group->discard_index = BTRFS_DISCARD_INDEX_START; + block_group->discard_eligible_time = (ktime_get_ns() + + BTRFS_DISCARD_DELAY); + block_group->discard_state = BTRFS_DISCARD_RESET_CURSOR; + } + + list_move_tail(&block_group->discard_list, + get_discard_list(discard_ctl, block_group)); +} + +static void add_to_discard_list(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + if (!btrfs_is_block_group_data_only(block_group)) + return; + + spin_lock(&discard_ctl->lock); + __add_to_discard_list(discard_ctl, block_group); + spin_unlock(&discard_ctl->lock); +} + +static void add_to_discard_unused_list(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + spin_lock(&discard_ctl->lock); + + if (!btrfs_run_discard_work(discard_ctl)) { + spin_unlock(&discard_ctl->lock); + return; + } + + list_del_init(&block_group->discard_list); + + block_group->discard_index = BTRFS_DISCARD_INDEX_UNUSED; + block_group->discard_eligible_time = (ktime_get_ns() + + BTRFS_DISCARD_UNUSED_DELAY); + block_group->discard_state = BTRFS_DISCARD_RESET_CURSOR; + list_add_tail(&block_group->discard_list, + &discard_ctl->discard_list[BTRFS_DISCARD_INDEX_UNUSED]); + + spin_unlock(&discard_ctl->lock); +} + +static bool remove_from_discard_list(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + bool running = false; + + spin_lock(&discard_ctl->lock); + + if (block_group == discard_ctl->block_group) { + running = true; + discard_ctl->block_group = NULL; + } + + block_group->discard_eligible_time = 0; + list_del_init(&block_group->discard_list); + + spin_unlock(&discard_ctl->lock); + + return running; +} + +/** + * find_next_block_group - find block_group that's up next for discarding + * @discard_ctl: discard control + * @now: current time + * + * Iterate over the discard lists to find the next block_group up for + * discarding checking the discard_eligible_time of block_group. + */ +static struct btrfs_block_group *find_next_block_group( + struct btrfs_discard_ctl *discard_ctl, + u64 now) +{ + struct btrfs_block_group *ret_block_group = NULL, *block_group; + int i; + + for (i = 0; i < BTRFS_NR_DISCARD_LISTS; i++) { + struct list_head *discard_list = &discard_ctl->discard_list[i]; + + if (!list_empty(discard_list)) { + block_group = list_first_entry(discard_list, + struct btrfs_block_group, + discard_list); + + if (!ret_block_group) + ret_block_group = block_group; + + if (ret_block_group->discard_eligible_time < now) + break; + + if (ret_block_group->discard_eligible_time > + block_group->discard_eligible_time) + ret_block_group = block_group; + } + } + + return ret_block_group; +} + +/** + * peek_discard_list - wrap find_next_block_group() + * @discard_ctl: discard control + * @discard_state: the discard_state of the block_group after state management + * @discard_index: the discard_index of the block_group after state management + * + * This wraps find_next_block_group() and sets the block_group to be in use. + * discard_state's control flow is managed here. Variables related to + * discard_state are reset here as needed (eg discard_cursor). @discard_state + * and @discard_index are remembered as it may change while we're discarding, + * but we want the discard to execute in the context determined here. + */ +static struct btrfs_block_group *peek_discard_list( + struct btrfs_discard_ctl *discard_ctl, + enum btrfs_discard_state *discard_state, + int *discard_index) +{ + struct btrfs_block_group *block_group; + const u64 now = ktime_get_ns(); + + spin_lock(&discard_ctl->lock); +again: + block_group = find_next_block_group(discard_ctl, now); + + if (block_group && now > block_group->discard_eligible_time) { + if (block_group->discard_index == BTRFS_DISCARD_INDEX_UNUSED && + block_group->used != 0) { + if (btrfs_is_block_group_data_only(block_group)) + __add_to_discard_list(discard_ctl, block_group); + else + list_del_init(&block_group->discard_list); + goto again; + } + if (block_group->discard_state == BTRFS_DISCARD_RESET_CURSOR) { + block_group->discard_cursor = block_group->start; + block_group->discard_state = BTRFS_DISCARD_EXTENTS; + } + discard_ctl->block_group = block_group; + *discard_state = block_group->discard_state; + *discard_index = block_group->discard_index; + } else { + block_group = NULL; + } + + spin_unlock(&discard_ctl->lock); + + return block_group; +} + +/** + * btrfs_discard_check_filter - updates a block groups filters + * @block_group: block group of interest + * @bytes: recently freed region size after coalescing + * + * Async discard maintains multiple lists with progressively smaller filters + * to prioritize discarding based on size. Should a free space that matches + * a larger filter be returned to the free_space_cache, prioritize that discard + * by moving @block_group to the proper filter. + */ +void btrfs_discard_check_filter(struct btrfs_block_group *block_group, + u64 bytes) +{ + struct btrfs_discard_ctl *discard_ctl; + + if (!block_group || + !btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC)) + return; + + discard_ctl = &block_group->fs_info->discard_ctl; + + if (block_group->discard_index > BTRFS_DISCARD_INDEX_START && + bytes >= discard_minlen[block_group->discard_index - 1]) { + int i; + + remove_from_discard_list(discard_ctl, block_group); + + for (i = BTRFS_DISCARD_INDEX_START; i < BTRFS_NR_DISCARD_LISTS; + i++) { + if (bytes >= discard_minlen[i]) { + block_group->discard_index = i; + add_to_discard_list(discard_ctl, block_group); + break; + } + } + } +} + +/** + * btrfs_update_discard_index - moves a block group along the discard lists + * @discard_ctl: discard control + * @block_group: block_group of interest + * + * Increment @block_group's discard_index. If it falls of the list, let it be. + * Otherwise add it back to the appropriate list. + */ +static void btrfs_update_discard_index(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + block_group->discard_index++; + if (block_group->discard_index == BTRFS_NR_DISCARD_LISTS) { + block_group->discard_index = 1; + return; + } + + add_to_discard_list(discard_ctl, block_group); +} + +/** + * btrfs_discard_cancel_work - remove a block_group from the discard lists + * @discard_ctl: discard control + * @block_group: block_group of interest + * + * This removes @block_group from the discard lists. If necessary, it waits on + * the current work and then reschedules the delayed work. + */ +void btrfs_discard_cancel_work(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + if (remove_from_discard_list(discard_ctl, block_group)) { + cancel_delayed_work_sync(&discard_ctl->work); + btrfs_discard_schedule_work(discard_ctl, true); + } +} + +/** + * btrfs_discard_queue_work - handles queuing the block_groups + * @discard_ctl: discard control + * @block_group: block_group of interest + * + * This maintains the LRU order of the discard lists. + */ +void btrfs_discard_queue_work(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + if (!block_group || !btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC)) + return; + + if (block_group->used == 0) + add_to_discard_unused_list(discard_ctl, block_group); + else + add_to_discard_list(discard_ctl, block_group); + + if (!delayed_work_pending(&discard_ctl->work)) + btrfs_discard_schedule_work(discard_ctl, false); +} + +/** + * btrfs_discard_schedule_work - responsible for scheduling the discard work + * @discard_ctl: discard control + * @override: override the current timer + * + * Discards are issued by a delayed workqueue item. @override is used to + * update the current delay as the baseline delay interval is reevaluated on + * transaction commit. This is also maxed with any other rate limit. + */ +void btrfs_discard_schedule_work(struct btrfs_discard_ctl *discard_ctl, + bool override) +{ + struct btrfs_block_group *block_group; + const u64 now = ktime_get_ns(); + + spin_lock(&discard_ctl->lock); + + if (!btrfs_run_discard_work(discard_ctl)) + goto out; + + if (!override && delayed_work_pending(&discard_ctl->work)) + goto out; + + block_group = find_next_block_group(discard_ctl, now); + if (block_group) { + unsigned long delay = discard_ctl->delay; + u32 kbps_limit = READ_ONCE(discard_ctl->kbps_limit); + + /* + * A single delayed workqueue item is responsible for + * discarding, so we can manage the bytes rate limit by keeping + * track of the previous discard. + */ + if (kbps_limit && discard_ctl->prev_discard) { + u64 bps_limit = ((u64)kbps_limit) * SZ_1K; + u64 bps_delay = div64_u64(discard_ctl->prev_discard * + MSEC_PER_SEC, bps_limit); + + delay = max(delay, msecs_to_jiffies(bps_delay)); + } + + /* + * This timeout is to hopefully prevent immediate discarding + * in a recently allocated block group. + */ + if (now < block_group->discard_eligible_time) { + u64 bg_timeout = block_group->discard_eligible_time - now; + + delay = max(delay, nsecs_to_jiffies(bg_timeout)); + } + + mod_delayed_work(discard_ctl->discard_workers, + &discard_ctl->work, delay); + } +out: + spin_unlock(&discard_ctl->lock); +} + +/** + * btrfs_finish_discard_pass - determine next step of a block_group + * @discard_ctl: discard control + * @block_group: block_group of interest + * + * This determines the next step for a block group after it's finished going + * through a pass on a discard list. If it is unused and fully trimmed, we can + * mark it unused and send it to the unused_bgs path. Otherwise, pass it onto + * the appropriate filter list or let it fall off. + */ +static void btrfs_finish_discard_pass(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group) +{ + remove_from_discard_list(discard_ctl, block_group); + + if (block_group->used == 0) { + if (btrfs_is_free_space_trimmed(block_group)) + btrfs_mark_bg_unused(block_group); + else + add_to_discard_unused_list(discard_ctl, block_group); + } else { + btrfs_update_discard_index(discard_ctl, block_group); + } +} + +/** + * btrfs_discard_workfn - discard work function + * @work: work + * + * This finds the next block_group to start discarding and then discards a + * single region. It does this in a two-pass fashion: first extents and second + * bitmaps. Completely discarded block groups are sent to the unused_bgs path. + */ +static void btrfs_discard_workfn(struct work_struct *work) +{ + struct btrfs_discard_ctl *discard_ctl; + struct btrfs_block_group *block_group; + enum btrfs_discard_state discard_state; + int discard_index = 0; + u64 trimmed = 0; + u64 minlen = 0; + + discard_ctl = container_of(work, struct btrfs_discard_ctl, work.work); + + block_group = peek_discard_list(discard_ctl, &discard_state, + &discard_index); + if (!block_group || !btrfs_run_discard_work(discard_ctl)) + return; + + /* Perform discarding */ + minlen = discard_minlen[discard_index]; + + if (discard_state == BTRFS_DISCARD_BITMAPS) { + u64 maxlen = 0; + + /* + * Use the previous levels minimum discard length as the max + * length filter. In the case something is added to make a + * region go beyond the max filter, the entire bitmap is set + * back to BTRFS_TRIM_STATE_UNTRIMMED. + */ + if (discard_index != BTRFS_DISCARD_INDEX_UNUSED) + maxlen = discard_minlen[discard_index - 1]; + + btrfs_trim_block_group_bitmaps(block_group, &trimmed, + block_group->discard_cursor, + btrfs_block_group_end(block_group), + minlen, maxlen, true); + discard_ctl->discard_bitmap_bytes += trimmed; + } else { + btrfs_trim_block_group_extents(block_group, &trimmed, + block_group->discard_cursor, + btrfs_block_group_end(block_group), + minlen, true); + discard_ctl->discard_extent_bytes += trimmed; + } + + discard_ctl->prev_discard = trimmed; + + /* Determine next steps for a block_group */ + if (block_group->discard_cursor >= btrfs_block_group_end(block_group)) { + if (discard_state == BTRFS_DISCARD_BITMAPS) { + btrfs_finish_discard_pass(discard_ctl, block_group); + } else { + block_group->discard_cursor = block_group->start; + spin_lock(&discard_ctl->lock); + if (block_group->discard_state != + BTRFS_DISCARD_RESET_CURSOR) + block_group->discard_state = + BTRFS_DISCARD_BITMAPS; + spin_unlock(&discard_ctl->lock); + } + } + + spin_lock(&discard_ctl->lock); + discard_ctl->block_group = NULL; + spin_unlock(&discard_ctl->lock); + + btrfs_discard_schedule_work(discard_ctl, false); +} + +/** + * btrfs_run_discard_work - determines if async discard should be running + * @discard_ctl: discard control + * + * Checks if the file system is writeable and BTRFS_FS_DISCARD_RUNNING is set. + */ +bool btrfs_run_discard_work(struct btrfs_discard_ctl *discard_ctl) +{ + struct btrfs_fs_info *fs_info = container_of(discard_ctl, + struct btrfs_fs_info, + discard_ctl); + + return (!(fs_info->sb->s_flags & SB_RDONLY) && + test_bit(BTRFS_FS_DISCARD_RUNNING, &fs_info->flags)); +} + +/** + * btrfs_discard_calc_delay - recalculate the base delay + * @discard_ctl: discard control + * + * Recalculate the base delay which is based off the total number of + * discardable_extents. Clamp this between the lower_limit (iops_limit or 1ms) + * and the upper_limit (BTRFS_DISCARD_MAX_DELAY_MSEC). + */ +void btrfs_discard_calc_delay(struct btrfs_discard_ctl *discard_ctl) +{ + s32 discardable_extents; + s64 discardable_bytes; + u32 iops_limit; + unsigned long delay; + unsigned long lower_limit = BTRFS_DISCARD_MIN_DELAY_MSEC; + + discardable_extents = atomic_read(&discard_ctl->discardable_extents); + if (!discardable_extents) + return; + + spin_lock(&discard_ctl->lock); + + /* + * The following is to fix a potential -1 discrepenancy that we're not + * sure how to reproduce. But given that this is the only place that + * utilizes these numbers and this is only called by from + * btrfs_finish_extent_commit() which is synchronized, we can correct + * here. + */ + if (discardable_extents < 0) + atomic_add(-discardable_extents, + &discard_ctl->discardable_extents); + + discardable_bytes = atomic64_read(&discard_ctl->discardable_bytes); + if (discardable_bytes < 0) + atomic64_add(-discardable_bytes, + &discard_ctl->discardable_bytes); + + if (discardable_extents <= 0) { + spin_unlock(&discard_ctl->lock); + return; + } + + iops_limit = READ_ONCE(discard_ctl->iops_limit); + if (iops_limit) + lower_limit = max_t(unsigned long, lower_limit, + MSEC_PER_SEC / iops_limit); + + delay = BTRFS_DISCARD_TARGET_MSEC / discardable_extents; + delay = clamp(delay, lower_limit, BTRFS_DISCARD_MAX_DELAY_MSEC); + discard_ctl->delay = msecs_to_jiffies(delay); + + spin_unlock(&discard_ctl->lock); +} + +/** + * btrfs_discard_update_discardable - propagate discard counters + * @block_group: block_group of interest + * @ctl: free_space_ctl of @block_group + * + * This propagates deltas of counters up to the discard_ctl. It maintains a + * current counter and a previous counter passing the delta up to the global + * stat. Then the current counter value becomes the previous counter value. + */ +void btrfs_discard_update_discardable(struct btrfs_block_group *block_group, + struct btrfs_free_space_ctl *ctl) +{ + struct btrfs_discard_ctl *discard_ctl; + s32 extents_delta; + s64 bytes_delta; + + if (!block_group || + !btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC) || + !btrfs_is_block_group_data_only(block_group)) + return; + + discard_ctl = &block_group->fs_info->discard_ctl; + + extents_delta = ctl->discardable_extents[BTRFS_STAT_CURR] - + ctl->discardable_extents[BTRFS_STAT_PREV]; + if (extents_delta) { + atomic_add(extents_delta, &discard_ctl->discardable_extents); + ctl->discardable_extents[BTRFS_STAT_PREV] = + ctl->discardable_extents[BTRFS_STAT_CURR]; + } + + bytes_delta = ctl->discardable_bytes[BTRFS_STAT_CURR] - + ctl->discardable_bytes[BTRFS_STAT_PREV]; + if (bytes_delta) { + atomic64_add(bytes_delta, &discard_ctl->discardable_bytes); + ctl->discardable_bytes[BTRFS_STAT_PREV] = + ctl->discardable_bytes[BTRFS_STAT_CURR]; + } +} + +/** + * btrfs_discard_punt_unused_bgs_list - punt unused_bgs list to discard lists + * @fs_info: fs_info of interest + * + * The unused_bgs list needs to be punted to the discard lists because the + * order of operations is changed. In the normal sychronous discard path, the + * block groups are trimmed via a single large trim in transaction commit. This + * is ultimately what we are trying to avoid with asynchronous discard. Thus, + * it must be done before going down the unused_bgs path. + */ +void btrfs_discard_punt_unused_bgs_list(struct btrfs_fs_info *fs_info) +{ + struct btrfs_block_group *block_group, *next; + + spin_lock(&fs_info->unused_bgs_lock); + /* We enabled async discard, so punt all to the queue */ + list_for_each_entry_safe(block_group, next, &fs_info->unused_bgs, + bg_list) { + list_del_init(&block_group->bg_list); + btrfs_discard_queue_work(&fs_info->discard_ctl, block_group); + } + spin_unlock(&fs_info->unused_bgs_lock); +} + +/** + * btrfs_discard_purge_list - purge discard lists + * @discard_ctl: discard control + * + * If we are disabling async discard, we may have intercepted block groups that + * are completely free and ready for the unused_bgs path. As discarding will + * now happen in transaction commit or not at all, we can safely mark the + * corresponding block groups as unused and they will be sent on their merry + * way to the unused_bgs list. + */ +static void btrfs_discard_purge_list(struct btrfs_discard_ctl *discard_ctl) +{ + struct btrfs_block_group *block_group, *next; + int i; + + spin_lock(&discard_ctl->lock); + for (i = 0; i < BTRFS_NR_DISCARD_LISTS; i++) { + list_for_each_entry_safe(block_group, next, + &discard_ctl->discard_list[i], + discard_list) { + list_del_init(&block_group->discard_list); + spin_unlock(&discard_ctl->lock); + if (block_group->used == 0) + btrfs_mark_bg_unused(block_group); + spin_lock(&discard_ctl->lock); + } + } + spin_unlock(&discard_ctl->lock); +} + +void btrfs_discard_resume(struct btrfs_fs_info *fs_info) +{ + if (!btrfs_test_opt(fs_info, DISCARD_ASYNC)) { + btrfs_discard_cleanup(fs_info); + return; + } + + btrfs_discard_punt_unused_bgs_list(fs_info); + + set_bit(BTRFS_FS_DISCARD_RUNNING, &fs_info->flags); +} + +void btrfs_discard_stop(struct btrfs_fs_info *fs_info) +{ + clear_bit(BTRFS_FS_DISCARD_RUNNING, &fs_info->flags); +} + +void btrfs_discard_init(struct btrfs_fs_info *fs_info) +{ + struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl; + int i; + + spin_lock_init(&discard_ctl->lock); + INIT_DELAYED_WORK(&discard_ctl->work, btrfs_discard_workfn); + + for (i = 0; i < BTRFS_NR_DISCARD_LISTS; i++) + INIT_LIST_HEAD(&discard_ctl->discard_list[i]); + + discard_ctl->prev_discard = 0; + atomic_set(&discard_ctl->discardable_extents, 0); + atomic64_set(&discard_ctl->discardable_bytes, 0); + discard_ctl->max_discard_size = BTRFS_ASYNC_DISCARD_DEFAULT_MAX_SIZE; + discard_ctl->delay = BTRFS_DISCARD_MAX_DELAY_MSEC; + discard_ctl->iops_limit = BTRFS_DISCARD_MAX_IOPS; + discard_ctl->kbps_limit = 0; + discard_ctl->discard_extent_bytes = 0; + discard_ctl->discard_bitmap_bytes = 0; + atomic64_set(&discard_ctl->discard_bytes_saved, 0); +} + +void btrfs_discard_cleanup(struct btrfs_fs_info *fs_info) +{ + btrfs_discard_stop(fs_info); + cancel_delayed_work_sync(&fs_info->discard_ctl.work); + btrfs_discard_purge_list(&fs_info->discard_ctl); +} |