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697 lines
18 KiB
697 lines
18 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (c) 2016-present, Facebook, Inc. |
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* All rights reserved. |
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* |
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*/ |
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|
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#include <linux/bio.h> |
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#include <linux/bitmap.h> |
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#include <linux/err.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/mm.h> |
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#include <linux/sched/mm.h> |
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#include <linux/pagemap.h> |
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#include <linux/refcount.h> |
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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#include <linux/zstd.h> |
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#include "misc.h" |
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#include "compression.h" |
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#include "ctree.h" |
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|
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#define ZSTD_BTRFS_MAX_WINDOWLOG 17 |
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#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG) |
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#define ZSTD_BTRFS_DEFAULT_LEVEL 3 |
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#define ZSTD_BTRFS_MAX_LEVEL 15 |
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/* 307s to avoid pathologically clashing with transaction commit */ |
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#define ZSTD_BTRFS_RECLAIM_JIFFIES (307 * HZ) |
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|
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static ZSTD_parameters zstd_get_btrfs_parameters(unsigned int level, |
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size_t src_len) |
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{ |
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ZSTD_parameters params = ZSTD_getParams(level, src_len, 0); |
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|
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if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG) |
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params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG; |
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WARN_ON(src_len > ZSTD_BTRFS_MAX_INPUT); |
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return params; |
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} |
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struct workspace { |
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void *mem; |
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size_t size; |
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char *buf; |
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unsigned int level; |
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unsigned int req_level; |
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unsigned long last_used; /* jiffies */ |
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struct list_head list; |
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struct list_head lru_list; |
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ZSTD_inBuffer in_buf; |
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ZSTD_outBuffer out_buf; |
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}; |
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|
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/* |
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* Zstd Workspace Management |
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* |
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* Zstd workspaces have different memory requirements depending on the level. |
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* The zstd workspaces are managed by having individual lists for each level |
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* and a global lru. Forward progress is maintained by protecting a max level |
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* workspace. |
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* |
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* Getting a workspace is done by using the bitmap to identify the levels that |
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* have available workspaces and scans up. This lets us recycle higher level |
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* workspaces because of the monotonic memory guarantee. A workspace's |
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* last_used is only updated if it is being used by the corresponding memory |
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* level. Putting a workspace involves adding it back to the appropriate places |
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* and adding it back to the lru if necessary. |
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* |
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* A timer is used to reclaim workspaces if they have not been used for |
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* ZSTD_BTRFS_RECLAIM_JIFFIES. This helps keep only active workspaces around. |
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* The upper bound is provided by the workqueue limit which is 2 (percpu limit). |
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*/ |
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struct zstd_workspace_manager { |
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const struct btrfs_compress_op *ops; |
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spinlock_t lock; |
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struct list_head lru_list; |
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struct list_head idle_ws[ZSTD_BTRFS_MAX_LEVEL]; |
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unsigned long active_map; |
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wait_queue_head_t wait; |
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struct timer_list timer; |
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}; |
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static struct zstd_workspace_manager wsm; |
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static size_t zstd_ws_mem_sizes[ZSTD_BTRFS_MAX_LEVEL]; |
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static inline struct workspace *list_to_workspace(struct list_head *list) |
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{ |
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return container_of(list, struct workspace, list); |
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} |
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|
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void zstd_free_workspace(struct list_head *ws); |
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struct list_head *zstd_alloc_workspace(unsigned int level); |
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/* |
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* zstd_reclaim_timer_fn - reclaim timer |
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* @t: timer |
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* |
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* This scans the lru_list and attempts to reclaim any workspace that hasn't |
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* been used for ZSTD_BTRFS_RECLAIM_JIFFIES. |
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*/ |
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static void zstd_reclaim_timer_fn(struct timer_list *timer) |
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{ |
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unsigned long reclaim_threshold = jiffies - ZSTD_BTRFS_RECLAIM_JIFFIES; |
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struct list_head *pos, *next; |
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spin_lock_bh(&wsm.lock); |
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if (list_empty(&wsm.lru_list)) { |
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spin_unlock_bh(&wsm.lock); |
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return; |
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} |
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list_for_each_prev_safe(pos, next, &wsm.lru_list) { |
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struct workspace *victim = container_of(pos, struct workspace, |
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lru_list); |
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unsigned int level; |
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if (time_after(victim->last_used, reclaim_threshold)) |
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break; |
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/* workspace is in use */ |
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if (victim->req_level) |
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continue; |
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level = victim->level; |
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list_del(&victim->lru_list); |
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list_del(&victim->list); |
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zstd_free_workspace(&victim->list); |
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if (list_empty(&wsm.idle_ws[level - 1])) |
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clear_bit(level - 1, &wsm.active_map); |
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} |
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if (!list_empty(&wsm.lru_list)) |
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mod_timer(&wsm.timer, jiffies + ZSTD_BTRFS_RECLAIM_JIFFIES); |
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spin_unlock_bh(&wsm.lock); |
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} |
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/* |
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* zstd_calc_ws_mem_sizes - calculate monotonic memory bounds |
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* |
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* It is possible based on the level configurations that a higher level |
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* workspace uses less memory than a lower level workspace. In order to reuse |
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* workspaces, this must be made a monotonic relationship. This precomputes |
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* the required memory for each level and enforces the monotonicity between |
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* level and memory required. |
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*/ |
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static void zstd_calc_ws_mem_sizes(void) |
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{ |
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size_t max_size = 0; |
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unsigned int level; |
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for (level = 1; level <= ZSTD_BTRFS_MAX_LEVEL; level++) { |
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ZSTD_parameters params = |
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zstd_get_btrfs_parameters(level, ZSTD_BTRFS_MAX_INPUT); |
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size_t level_size = |
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max_t(size_t, |
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ZSTD_CStreamWorkspaceBound(params.cParams), |
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ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT)); |
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max_size = max_t(size_t, max_size, level_size); |
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zstd_ws_mem_sizes[level - 1] = max_size; |
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} |
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} |
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void zstd_init_workspace_manager(void) |
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{ |
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struct list_head *ws; |
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int i; |
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zstd_calc_ws_mem_sizes(); |
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wsm.ops = &btrfs_zstd_compress; |
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spin_lock_init(&wsm.lock); |
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init_waitqueue_head(&wsm.wait); |
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timer_setup(&wsm.timer, zstd_reclaim_timer_fn, 0); |
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INIT_LIST_HEAD(&wsm.lru_list); |
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for (i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++) |
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INIT_LIST_HEAD(&wsm.idle_ws[i]); |
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ws = zstd_alloc_workspace(ZSTD_BTRFS_MAX_LEVEL); |
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if (IS_ERR(ws)) { |
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pr_warn( |
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"BTRFS: cannot preallocate zstd compression workspace\n"); |
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} else { |
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set_bit(ZSTD_BTRFS_MAX_LEVEL - 1, &wsm.active_map); |
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list_add(ws, &wsm.idle_ws[ZSTD_BTRFS_MAX_LEVEL - 1]); |
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} |
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} |
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void zstd_cleanup_workspace_manager(void) |
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{ |
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struct workspace *workspace; |
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int i; |
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spin_lock_bh(&wsm.lock); |
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for (i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++) { |
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while (!list_empty(&wsm.idle_ws[i])) { |
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workspace = container_of(wsm.idle_ws[i].next, |
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struct workspace, list); |
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list_del(&workspace->list); |
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list_del(&workspace->lru_list); |
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zstd_free_workspace(&workspace->list); |
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} |
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} |
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spin_unlock_bh(&wsm.lock); |
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del_timer_sync(&wsm.timer); |
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} |
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/* |
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* zstd_find_workspace - find workspace |
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* @level: compression level |
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* |
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* This iterates over the set bits in the active_map beginning at the requested |
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* compression level. This lets us utilize already allocated workspaces before |
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* allocating a new one. If the workspace is of a larger size, it is used, but |
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* the place in the lru_list and last_used times are not updated. This is to |
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* offer the opportunity to reclaim the workspace in favor of allocating an |
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* appropriately sized one in the future. |
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*/ |
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static struct list_head *zstd_find_workspace(unsigned int level) |
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{ |
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struct list_head *ws; |
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struct workspace *workspace; |
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int i = level - 1; |
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spin_lock_bh(&wsm.lock); |
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for_each_set_bit_from(i, &wsm.active_map, ZSTD_BTRFS_MAX_LEVEL) { |
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if (!list_empty(&wsm.idle_ws[i])) { |
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ws = wsm.idle_ws[i].next; |
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workspace = list_to_workspace(ws); |
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list_del_init(ws); |
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/* keep its place if it's a lower level using this */ |
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workspace->req_level = level; |
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if (level == workspace->level) |
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list_del(&workspace->lru_list); |
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if (list_empty(&wsm.idle_ws[i])) |
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clear_bit(i, &wsm.active_map); |
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spin_unlock_bh(&wsm.lock); |
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return ws; |
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} |
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} |
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spin_unlock_bh(&wsm.lock); |
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return NULL; |
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} |
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/* |
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* zstd_get_workspace - zstd's get_workspace |
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* @level: compression level |
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* |
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* If @level is 0, then any compression level can be used. Therefore, we begin |
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* scanning from 1. We first scan through possible workspaces and then after |
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* attempt to allocate a new workspace. If we fail to allocate one due to |
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* memory pressure, go to sleep waiting for the max level workspace to free up. |
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*/ |
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struct list_head *zstd_get_workspace(unsigned int level) |
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{ |
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struct list_head *ws; |
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unsigned int nofs_flag; |
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/* level == 0 means we can use any workspace */ |
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if (!level) |
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level = 1; |
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again: |
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ws = zstd_find_workspace(level); |
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if (ws) |
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return ws; |
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nofs_flag = memalloc_nofs_save(); |
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ws = zstd_alloc_workspace(level); |
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memalloc_nofs_restore(nofs_flag); |
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if (IS_ERR(ws)) { |
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DEFINE_WAIT(wait); |
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prepare_to_wait(&wsm.wait, &wait, TASK_UNINTERRUPTIBLE); |
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schedule(); |
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finish_wait(&wsm.wait, &wait); |
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goto again; |
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} |
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return ws; |
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} |
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/* |
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* zstd_put_workspace - zstd put_workspace |
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* @ws: list_head for the workspace |
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* |
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* When putting back a workspace, we only need to update the LRU if we are of |
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* the requested compression level. Here is where we continue to protect the |
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* max level workspace or update last_used accordingly. If the reclaim timer |
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* isn't set, it is also set here. Only the max level workspace tries and wakes |
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* up waiting workspaces. |
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*/ |
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void zstd_put_workspace(struct list_head *ws) |
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{ |
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struct workspace *workspace = list_to_workspace(ws); |
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spin_lock_bh(&wsm.lock); |
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/* A node is only taken off the lru if we are the corresponding level */ |
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if (workspace->req_level == workspace->level) { |
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/* Hide a max level workspace from reclaim */ |
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if (list_empty(&wsm.idle_ws[ZSTD_BTRFS_MAX_LEVEL - 1])) { |
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INIT_LIST_HEAD(&workspace->lru_list); |
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} else { |
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workspace->last_used = jiffies; |
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list_add(&workspace->lru_list, &wsm.lru_list); |
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if (!timer_pending(&wsm.timer)) |
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mod_timer(&wsm.timer, |
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jiffies + ZSTD_BTRFS_RECLAIM_JIFFIES); |
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} |
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} |
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set_bit(workspace->level - 1, &wsm.active_map); |
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list_add(&workspace->list, &wsm.idle_ws[workspace->level - 1]); |
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workspace->req_level = 0; |
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spin_unlock_bh(&wsm.lock); |
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if (workspace->level == ZSTD_BTRFS_MAX_LEVEL) |
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cond_wake_up(&wsm.wait); |
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} |
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void zstd_free_workspace(struct list_head *ws) |
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{ |
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struct workspace *workspace = list_entry(ws, struct workspace, list); |
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kvfree(workspace->mem); |
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kfree(workspace->buf); |
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kfree(workspace); |
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} |
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struct list_head *zstd_alloc_workspace(unsigned int level) |
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{ |
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struct workspace *workspace; |
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workspace = kzalloc(sizeof(*workspace), GFP_KERNEL); |
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if (!workspace) |
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return ERR_PTR(-ENOMEM); |
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workspace->size = zstd_ws_mem_sizes[level - 1]; |
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workspace->level = level; |
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workspace->req_level = level; |
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workspace->last_used = jiffies; |
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workspace->mem = kvmalloc(workspace->size, GFP_KERNEL); |
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workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
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if (!workspace->mem || !workspace->buf) |
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goto fail; |
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INIT_LIST_HEAD(&workspace->list); |
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INIT_LIST_HEAD(&workspace->lru_list); |
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return &workspace->list; |
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fail: |
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zstd_free_workspace(&workspace->list); |
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return ERR_PTR(-ENOMEM); |
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} |
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int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, |
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u64 start, struct page **pages, unsigned long *out_pages, |
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unsigned long *total_in, unsigned long *total_out) |
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{ |
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struct workspace *workspace = list_entry(ws, struct workspace, list); |
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ZSTD_CStream *stream; |
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int ret = 0; |
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int nr_pages = 0; |
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struct page *in_page = NULL; /* The current page to read */ |
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struct page *out_page = NULL; /* The current page to write to */ |
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unsigned long tot_in = 0; |
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unsigned long tot_out = 0; |
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unsigned long len = *total_out; |
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const unsigned long nr_dest_pages = *out_pages; |
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unsigned long max_out = nr_dest_pages * PAGE_SIZE; |
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ZSTD_parameters params = zstd_get_btrfs_parameters(workspace->req_level, |
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len); |
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*out_pages = 0; |
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*total_out = 0; |
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*total_in = 0; |
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/* Initialize the stream */ |
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stream = ZSTD_initCStream(params, len, workspace->mem, |
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workspace->size); |
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if (!stream) { |
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pr_warn("BTRFS: ZSTD_initCStream failed\n"); |
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ret = -EIO; |
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goto out; |
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} |
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/* map in the first page of input data */ |
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in_page = find_get_page(mapping, start >> PAGE_SHIFT); |
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workspace->in_buf.src = page_address(in_page); |
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workspace->in_buf.pos = 0; |
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workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE); |
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/* Allocate and map in the output buffer */ |
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out_page = alloc_page(GFP_NOFS); |
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if (out_page == NULL) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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pages[nr_pages++] = out_page; |
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workspace->out_buf.dst = page_address(out_page); |
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workspace->out_buf.pos = 0; |
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workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE); |
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while (1) { |
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size_t ret2; |
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ret2 = ZSTD_compressStream(stream, &workspace->out_buf, |
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&workspace->in_buf); |
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if (ZSTD_isError(ret2)) { |
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pr_debug("BTRFS: ZSTD_compressStream returned %d\n", |
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ZSTD_getErrorCode(ret2)); |
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ret = -EIO; |
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goto out; |
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} |
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|
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/* Check to see if we are making it bigger */ |
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if (tot_in + workspace->in_buf.pos > 8192 && |
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tot_in + workspace->in_buf.pos < |
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tot_out + workspace->out_buf.pos) { |
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ret = -E2BIG; |
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goto out; |
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} |
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|
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/* We've reached the end of our output range */ |
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if (workspace->out_buf.pos >= max_out) { |
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tot_out += workspace->out_buf.pos; |
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ret = -E2BIG; |
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goto out; |
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} |
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|
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/* Check if we need more output space */ |
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if (workspace->out_buf.pos == workspace->out_buf.size) { |
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tot_out += PAGE_SIZE; |
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max_out -= PAGE_SIZE; |
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if (nr_pages == nr_dest_pages) { |
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out_page = NULL; |
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ret = -E2BIG; |
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goto out; |
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} |
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out_page = alloc_page(GFP_NOFS); |
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if (out_page == NULL) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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pages[nr_pages++] = out_page; |
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workspace->out_buf.dst = page_address(out_page); |
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workspace->out_buf.pos = 0; |
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workspace->out_buf.size = min_t(size_t, max_out, |
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PAGE_SIZE); |
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} |
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|
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/* We've reached the end of the input */ |
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if (workspace->in_buf.pos >= len) { |
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tot_in += workspace->in_buf.pos; |
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break; |
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} |
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|
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/* Check if we need more input */ |
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if (workspace->in_buf.pos == workspace->in_buf.size) { |
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tot_in += PAGE_SIZE; |
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put_page(in_page); |
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|
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start += PAGE_SIZE; |
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len -= PAGE_SIZE; |
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in_page = find_get_page(mapping, start >> PAGE_SHIFT); |
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workspace->in_buf.src = page_address(in_page); |
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workspace->in_buf.pos = 0; |
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workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE); |
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} |
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} |
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while (1) { |
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size_t ret2; |
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|
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ret2 = ZSTD_endStream(stream, &workspace->out_buf); |
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if (ZSTD_isError(ret2)) { |
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pr_debug("BTRFS: ZSTD_endStream returned %d\n", |
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ZSTD_getErrorCode(ret2)); |
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ret = -EIO; |
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goto out; |
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} |
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if (ret2 == 0) { |
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tot_out += workspace->out_buf.pos; |
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break; |
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} |
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if (workspace->out_buf.pos >= max_out) { |
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tot_out += workspace->out_buf.pos; |
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ret = -E2BIG; |
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goto out; |
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} |
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|
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tot_out += PAGE_SIZE; |
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max_out -= PAGE_SIZE; |
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if (nr_pages == nr_dest_pages) { |
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out_page = NULL; |
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ret = -E2BIG; |
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goto out; |
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} |
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out_page = alloc_page(GFP_NOFS); |
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if (out_page == NULL) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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pages[nr_pages++] = out_page; |
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workspace->out_buf.dst = page_address(out_page); |
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workspace->out_buf.pos = 0; |
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workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE); |
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} |
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|
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if (tot_out >= tot_in) { |
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ret = -E2BIG; |
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goto out; |
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} |
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|
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ret = 0; |
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*total_in = tot_in; |
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*total_out = tot_out; |
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out: |
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*out_pages = nr_pages; |
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/* Cleanup */ |
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if (in_page) |
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put_page(in_page); |
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return ret; |
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} |
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|
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int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) |
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{ |
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struct workspace *workspace = list_entry(ws, struct workspace, list); |
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struct page **pages_in = cb->compressed_pages; |
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size_t srclen = cb->compressed_len; |
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ZSTD_DStream *stream; |
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int ret = 0; |
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unsigned long page_in_index = 0; |
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unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); |
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unsigned long buf_start; |
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unsigned long total_out = 0; |
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|
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stream = ZSTD_initDStream( |
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ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size); |
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if (!stream) { |
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pr_debug("BTRFS: ZSTD_initDStream failed\n"); |
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ret = -EIO; |
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goto done; |
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} |
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|
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workspace->in_buf.src = page_address(pages_in[page_in_index]); |
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workspace->in_buf.pos = 0; |
|
workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE); |
|
|
|
workspace->out_buf.dst = workspace->buf; |
|
workspace->out_buf.pos = 0; |
|
workspace->out_buf.size = PAGE_SIZE; |
|
|
|
while (1) { |
|
size_t ret2; |
|
|
|
ret2 = ZSTD_decompressStream(stream, &workspace->out_buf, |
|
&workspace->in_buf); |
|
if (ZSTD_isError(ret2)) { |
|
pr_debug("BTRFS: ZSTD_decompressStream returned %d\n", |
|
ZSTD_getErrorCode(ret2)); |
|
ret = -EIO; |
|
goto done; |
|
} |
|
buf_start = total_out; |
|
total_out += workspace->out_buf.pos; |
|
workspace->out_buf.pos = 0; |
|
|
|
ret = btrfs_decompress_buf2page(workspace->out_buf.dst, |
|
total_out - buf_start, cb, buf_start); |
|
if (ret == 0) |
|
break; |
|
|
|
if (workspace->in_buf.pos >= srclen) |
|
break; |
|
|
|
/* Check if we've hit the end of a frame */ |
|
if (ret2 == 0) |
|
break; |
|
|
|
if (workspace->in_buf.pos == workspace->in_buf.size) { |
|
page_in_index++; |
|
if (page_in_index >= total_pages_in) { |
|
workspace->in_buf.src = NULL; |
|
ret = -EIO; |
|
goto done; |
|
} |
|
srclen -= PAGE_SIZE; |
|
workspace->in_buf.src = page_address(pages_in[page_in_index]); |
|
workspace->in_buf.pos = 0; |
|
workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE); |
|
} |
|
} |
|
ret = 0; |
|
zero_fill_bio(cb->orig_bio); |
|
done: |
|
return ret; |
|
} |
|
|
|
int zstd_decompress(struct list_head *ws, unsigned char *data_in, |
|
struct page *dest_page, unsigned long start_byte, size_t srclen, |
|
size_t destlen) |
|
{ |
|
struct workspace *workspace = list_entry(ws, struct workspace, list); |
|
ZSTD_DStream *stream; |
|
int ret = 0; |
|
size_t ret2; |
|
unsigned long total_out = 0; |
|
unsigned long pg_offset = 0; |
|
|
|
stream = ZSTD_initDStream( |
|
ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size); |
|
if (!stream) { |
|
pr_warn("BTRFS: ZSTD_initDStream failed\n"); |
|
ret = -EIO; |
|
goto finish; |
|
} |
|
|
|
destlen = min_t(size_t, destlen, PAGE_SIZE); |
|
|
|
workspace->in_buf.src = data_in; |
|
workspace->in_buf.pos = 0; |
|
workspace->in_buf.size = srclen; |
|
|
|
workspace->out_buf.dst = workspace->buf; |
|
workspace->out_buf.pos = 0; |
|
workspace->out_buf.size = PAGE_SIZE; |
|
|
|
ret2 = 1; |
|
while (pg_offset < destlen |
|
&& workspace->in_buf.pos < workspace->in_buf.size) { |
|
unsigned long buf_start; |
|
unsigned long buf_offset; |
|
unsigned long bytes; |
|
|
|
/* Check if the frame is over and we still need more input */ |
|
if (ret2 == 0) { |
|
pr_debug("BTRFS: ZSTD_decompressStream ended early\n"); |
|
ret = -EIO; |
|
goto finish; |
|
} |
|
ret2 = ZSTD_decompressStream(stream, &workspace->out_buf, |
|
&workspace->in_buf); |
|
if (ZSTD_isError(ret2)) { |
|
pr_debug("BTRFS: ZSTD_decompressStream returned %d\n", |
|
ZSTD_getErrorCode(ret2)); |
|
ret = -EIO; |
|
goto finish; |
|
} |
|
|
|
buf_start = total_out; |
|
total_out += workspace->out_buf.pos; |
|
workspace->out_buf.pos = 0; |
|
|
|
if (total_out <= start_byte) |
|
continue; |
|
|
|
if (total_out > start_byte && buf_start < start_byte) |
|
buf_offset = start_byte - buf_start; |
|
else |
|
buf_offset = 0; |
|
|
|
bytes = min_t(unsigned long, destlen - pg_offset, |
|
workspace->out_buf.size - buf_offset); |
|
|
|
memcpy_to_page(dest_page, pg_offset, |
|
workspace->out_buf.dst + buf_offset, bytes); |
|
|
|
pg_offset += bytes; |
|
} |
|
ret = 0; |
|
finish: |
|
if (pg_offset < destlen) { |
|
memzero_page(dest_page, pg_offset, destlen - pg_offset); |
|
} |
|
return ret; |
|
} |
|
|
|
const struct btrfs_compress_op btrfs_zstd_compress = { |
|
/* ZSTD uses own workspace manager */ |
|
.workspace_manager = NULL, |
|
.max_level = ZSTD_BTRFS_MAX_LEVEL, |
|
.default_level = ZSTD_BTRFS_DEFAULT_LEVEL, |
|
};
|
|
|