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-rw-r--r--fs/btrfs/zstd.c737
1 files changed, 737 insertions, 0 deletions
diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
new file mode 100644
index 000000000000..c9cddcfa337b
--- /dev/null
+++ b/fs/btrfs/zstd.c
@@ -0,0 +1,737 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ */
+
+#include <linux/bio.h>
+#include <linux/bitmap.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/pagemap.h>
+#include <linux/refcount.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/zstd.h>
+#include "misc.h"
+#include "fs.h"
+#include "btrfs_inode.h"
+#include "compression.h"
+#include "super.h"
+
+#define ZSTD_BTRFS_MAX_WINDOWLOG 17
+#define ZSTD_BTRFS_MAX_INPUT (1U << ZSTD_BTRFS_MAX_WINDOWLOG)
+#define ZSTD_BTRFS_DEFAULT_LEVEL 3
+#define ZSTD_BTRFS_MIN_LEVEL -15
+#define ZSTD_BTRFS_MAX_LEVEL 15
+/* 307s to avoid pathologically clashing with transaction commit */
+#define ZSTD_BTRFS_RECLAIM_JIFFIES (307 * HZ)
+
+static zstd_parameters zstd_get_btrfs_parameters(int level,
+ size_t src_len)
+{
+ zstd_parameters params = zstd_get_params(level, src_len);
+
+ if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG)
+ params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG;
+ WARN_ON(src_len > ZSTD_BTRFS_MAX_INPUT);
+ return params;
+}
+
+struct workspace {
+ void *mem;
+ size_t size;
+ char *buf;
+ int level;
+ int req_level;
+ unsigned long last_used; /* jiffies */
+ struct list_head list;
+ struct list_head lru_list;
+ zstd_in_buffer in_buf;
+ zstd_out_buffer out_buf;
+ zstd_parameters params;
+};
+
+/*
+ * Zstd Workspace Management
+ *
+ * Zstd workspaces have different memory requirements depending on the level.
+ * The zstd workspaces are managed by having individual lists for each level
+ * and a global lru. Forward progress is maintained by protecting a max level
+ * workspace.
+ *
+ * Getting a workspace is done by using the bitmap to identify the levels that
+ * have available workspaces and scans up. This lets us recycle higher level
+ * workspaces because of the monotonic memory guarantee. A workspace's
+ * last_used is only updated if it is being used by the corresponding memory
+ * level. Putting a workspace involves adding it back to the appropriate places
+ * and adding it back to the lru if necessary.
+ *
+ * A timer is used to reclaim workspaces if they have not been used for
+ * ZSTD_BTRFS_RECLAIM_JIFFIES. This helps keep only active workspaces around.
+ * The upper bound is provided by the workqueue limit which is 2 (percpu limit).
+ */
+
+struct zstd_workspace_manager {
+ spinlock_t lock;
+ struct list_head lru_list;
+ struct list_head idle_ws[ZSTD_BTRFS_MAX_LEVEL];
+ unsigned long active_map;
+ wait_queue_head_t wait;
+ struct timer_list timer;
+};
+
+static size_t zstd_ws_mem_sizes[ZSTD_BTRFS_MAX_LEVEL];
+
+static inline struct workspace *list_to_workspace(struct list_head *list)
+{
+ return container_of(list, struct workspace, list);
+}
+
+static inline int clip_level(int level)
+{
+ return max(0, level - 1);
+}
+
+/*
+ * Timer callback to free unused workspaces.
+ *
+ * @t: timer
+ *
+ * This scans the lru_list and attempts to reclaim any workspace that hasn't
+ * been used for ZSTD_BTRFS_RECLAIM_JIFFIES.
+ *
+ * The context is softirq and does not need the _bh locking primitives.
+ */
+static void zstd_reclaim_timer_fn(struct timer_list *timer)
+{
+ struct zstd_workspace_manager *zwsm =
+ container_of(timer, struct zstd_workspace_manager, timer);
+ unsigned long reclaim_threshold = jiffies - ZSTD_BTRFS_RECLAIM_JIFFIES;
+ struct list_head *pos, *next;
+
+ spin_lock(&zwsm->lock);
+
+ if (list_empty(&zwsm->lru_list)) {
+ spin_unlock(&zwsm->lock);
+ return;
+ }
+
+ list_for_each_prev_safe(pos, next, &zwsm->lru_list) {
+ struct workspace *victim = container_of(pos, struct workspace,
+ lru_list);
+ int level;
+
+ if (time_after(victim->last_used, reclaim_threshold))
+ break;
+
+ /* workspace is in use */
+ if (victim->req_level)
+ continue;
+
+ level = victim->level;
+ list_del(&victim->lru_list);
+ list_del(&victim->list);
+ zstd_free_workspace(&victim->list);
+
+ if (list_empty(&zwsm->idle_ws[level]))
+ clear_bit(level, &zwsm->active_map);
+
+ }
+
+ if (!list_empty(&zwsm->lru_list))
+ mod_timer(&zwsm->timer, jiffies + ZSTD_BTRFS_RECLAIM_JIFFIES);
+
+ spin_unlock(&zwsm->lock);
+}
+
+/*
+ * Calculate monotonic memory bounds.
+ *
+ * It is possible based on the level configurations that a higher level
+ * workspace uses less memory than a lower level workspace. In order to reuse
+ * workspaces, this must be made a monotonic relationship. This precomputes
+ * the required memory for each level and enforces the monotonicity between
+ * level and memory required.
+ */
+static void zstd_calc_ws_mem_sizes(void)
+{
+ size_t max_size = 0;
+ int level;
+
+ for (level = ZSTD_BTRFS_MIN_LEVEL; level <= ZSTD_BTRFS_MAX_LEVEL; level++) {
+ if (level == 0)
+ continue;
+ zstd_parameters params =
+ zstd_get_btrfs_parameters(level, ZSTD_BTRFS_MAX_INPUT);
+ size_t level_size =
+ max_t(size_t,
+ zstd_cstream_workspace_bound(&params.cParams),
+ zstd_dstream_workspace_bound(ZSTD_BTRFS_MAX_INPUT));
+
+ max_size = max_t(size_t, max_size, level_size);
+ /* Use level 1 workspace size for all the fast mode negative levels. */
+ zstd_ws_mem_sizes[clip_level(level)] = max_size;
+ }
+}
+
+int zstd_alloc_workspace_manager(struct btrfs_fs_info *fs_info)
+{
+ struct zstd_workspace_manager *zwsm;
+ struct list_head *ws;
+
+ ASSERT(fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] == NULL);
+ zwsm = kzalloc(sizeof(*zwsm), GFP_KERNEL);
+ if (!zwsm)
+ return -ENOMEM;
+ zstd_calc_ws_mem_sizes();
+ spin_lock_init(&zwsm->lock);
+ init_waitqueue_head(&zwsm->wait);
+ timer_setup(&zwsm->timer, zstd_reclaim_timer_fn, 0);
+
+ INIT_LIST_HEAD(&zwsm->lru_list);
+ for (int i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++)
+ INIT_LIST_HEAD(&zwsm->idle_ws[i]);
+ fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] = zwsm;
+
+ ws = zstd_alloc_workspace(fs_info, ZSTD_BTRFS_MAX_LEVEL);
+ if (IS_ERR(ws)) {
+ btrfs_warn(NULL, "cannot preallocate zstd compression workspace");
+ } else {
+ set_bit(ZSTD_BTRFS_MAX_LEVEL - 1, &zwsm->active_map);
+ list_add(ws, &zwsm->idle_ws[ZSTD_BTRFS_MAX_LEVEL - 1]);
+ }
+ return 0;
+}
+
+void zstd_free_workspace_manager(struct btrfs_fs_info *fs_info)
+{
+ struct zstd_workspace_manager *zwsm = fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD];
+ struct workspace *workspace;
+
+ if (!zwsm)
+ return;
+ fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] = NULL;
+ spin_lock_bh(&zwsm->lock);
+ for (int i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++) {
+ while (!list_empty(&zwsm->idle_ws[i])) {
+ workspace = container_of(zwsm->idle_ws[i].next,
+ struct workspace, list);
+ list_del(&workspace->list);
+ list_del(&workspace->lru_list);
+ zstd_free_workspace(&workspace->list);
+ }
+ }
+ spin_unlock_bh(&zwsm->lock);
+ timer_delete_sync(&zwsm->timer);
+ kfree(zwsm);
+}
+
+/*
+ * Find workspace for given level.
+ *
+ * @level: compression level
+ *
+ * This iterates over the set bits in the active_map beginning at the requested
+ * compression level. This lets us utilize already allocated workspaces before
+ * allocating a new one. If the workspace is of a larger size, it is used, but
+ * the place in the lru_list and last_used times are not updated. This is to
+ * offer the opportunity to reclaim the workspace in favor of allocating an
+ * appropriately sized one in the future.
+ */
+static struct list_head *zstd_find_workspace(struct btrfs_fs_info *fs_info, int level)
+{
+ struct zstd_workspace_manager *zwsm = fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD];
+ struct list_head *ws;
+ struct workspace *workspace;
+ int i = clip_level(level);
+
+ ASSERT(zwsm);
+ spin_lock_bh(&zwsm->lock);
+ for_each_set_bit_from(i, &zwsm->active_map, ZSTD_BTRFS_MAX_LEVEL) {
+ if (!list_empty(&zwsm->idle_ws[i])) {
+ ws = zwsm->idle_ws[i].next;
+ workspace = list_to_workspace(ws);
+ list_del_init(ws);
+ /* keep its place if it's a lower level using this */
+ workspace->req_level = level;
+ if (clip_level(level) == workspace->level)
+ list_del(&workspace->lru_list);
+ if (list_empty(&zwsm->idle_ws[i]))
+ clear_bit(i, &zwsm->active_map);
+ spin_unlock_bh(&zwsm->lock);
+ return ws;
+ }
+ }
+ spin_unlock_bh(&zwsm->lock);
+
+ return NULL;
+}
+
+/*
+ * Zstd get_workspace for level.
+ *
+ * @level: compression level
+ *
+ * If @level is 0, then any compression level can be used. Therefore, we begin
+ * scanning from 1. We first scan through possible workspaces and then after
+ * attempt to allocate a new workspace. If we fail to allocate one due to
+ * memory pressure, go to sleep waiting for the max level workspace to free up.
+ */
+struct list_head *zstd_get_workspace(struct btrfs_fs_info *fs_info, int level)
+{
+ struct zstd_workspace_manager *zwsm = fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD];
+ struct list_head *ws;
+ unsigned int nofs_flag;
+
+ ASSERT(zwsm);
+
+ /* level == 0 means we can use any workspace */
+ if (!level)
+ level = 1;
+
+again:
+ ws = zstd_find_workspace(fs_info, level);
+ if (ws)
+ return ws;
+
+ nofs_flag = memalloc_nofs_save();
+ ws = zstd_alloc_workspace(fs_info, level);
+ memalloc_nofs_restore(nofs_flag);
+
+ if (IS_ERR(ws)) {
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&zwsm->wait, &wait, TASK_UNINTERRUPTIBLE);
+ schedule();
+ finish_wait(&zwsm->wait, &wait);
+
+ goto again;
+ }
+
+ return ws;
+}
+
+/*
+ * Zstd put_workspace.
+ *
+ * @ws: list_head for the workspace
+ *
+ * When putting back a workspace, we only need to update the LRU if we are of
+ * the requested compression level. Here is where we continue to protect the
+ * max level workspace or update last_used accordingly. If the reclaim timer
+ * isn't set, it is also set here. Only the max level workspace tries and wakes
+ * up waiting workspaces.
+ */
+void zstd_put_workspace(struct btrfs_fs_info *fs_info, struct list_head *ws)
+{
+ struct zstd_workspace_manager *zwsm = fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD];
+ struct workspace *workspace = list_to_workspace(ws);
+
+ ASSERT(zwsm);
+ spin_lock_bh(&zwsm->lock);
+
+ /* A node is only taken off the lru if we are the corresponding level */
+ if (clip_level(workspace->req_level) == workspace->level) {
+ /* Hide a max level workspace from reclaim */
+ if (list_empty(&zwsm->idle_ws[ZSTD_BTRFS_MAX_LEVEL - 1])) {
+ INIT_LIST_HEAD(&workspace->lru_list);
+ } else {
+ workspace->last_used = jiffies;
+ list_add(&workspace->lru_list, &zwsm->lru_list);
+ if (!timer_pending(&zwsm->timer))
+ mod_timer(&zwsm->timer,
+ jiffies + ZSTD_BTRFS_RECLAIM_JIFFIES);
+ }
+ }
+
+ set_bit(workspace->level, &zwsm->active_map);
+ list_add(&workspace->list, &zwsm->idle_ws[workspace->level]);
+ workspace->req_level = 0;
+
+ spin_unlock_bh(&zwsm->lock);
+
+ if (workspace->level == clip_level(ZSTD_BTRFS_MAX_LEVEL))
+ cond_wake_up(&zwsm->wait);
+}
+
+void zstd_free_workspace(struct list_head *ws)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+
+ kvfree(workspace->mem);
+ kfree(workspace->buf);
+ kfree(workspace);
+}
+
+struct list_head *zstd_alloc_workspace(struct btrfs_fs_info *fs_info, int level)
+{
+ const u32 blocksize = fs_info->sectorsize;
+ struct workspace *workspace;
+
+ workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
+ if (!workspace)
+ return ERR_PTR(-ENOMEM);
+
+ /* Use level 1 workspace size for all the fast mode negative levels. */
+ workspace->size = zstd_ws_mem_sizes[clip_level(level)];
+ workspace->level = clip_level(level);
+ workspace->req_level = level;
+ workspace->last_used = jiffies;
+ workspace->mem = kvmalloc(workspace->size, GFP_KERNEL | __GFP_NOWARN);
+ workspace->buf = kmalloc(blocksize, GFP_KERNEL);
+ if (!workspace->mem || !workspace->buf)
+ goto fail;
+
+ INIT_LIST_HEAD(&workspace->list);
+ INIT_LIST_HEAD(&workspace->lru_list);
+
+ return &workspace->list;
+fail:
+ zstd_free_workspace(&workspace->list);
+ return ERR_PTR(-ENOMEM);
+}
+
+int zstd_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
+ u64 start, struct folio **folios, unsigned long *out_folios,
+ unsigned long *total_in, unsigned long *total_out)
+{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct address_space *mapping = inode->vfs_inode.i_mapping;
+ zstd_cstream *stream;
+ int ret = 0;
+ int nr_folios = 0;
+ struct folio *in_folio = NULL; /* The current folio to read. */
+ struct folio *out_folio = NULL; /* The current folio to write to. */
+ unsigned long tot_in = 0;
+ unsigned long tot_out = 0;
+ unsigned long len = *total_out;
+ const unsigned long nr_dest_folios = *out_folios;
+ const u64 orig_end = start + len;
+ const u32 blocksize = fs_info->sectorsize;
+ const u32 min_folio_size = btrfs_min_folio_size(fs_info);
+ unsigned long max_out = nr_dest_folios * min_folio_size;
+ unsigned int cur_len;
+
+ workspace->params = zstd_get_btrfs_parameters(workspace->req_level, len);
+ *out_folios = 0;
+ *total_out = 0;
+ *total_in = 0;
+
+ /* Initialize the stream */
+ stream = zstd_init_cstream(&workspace->params, len, workspace->mem,
+ workspace->size);
+ if (unlikely(!stream)) {
+ btrfs_err(fs_info,
+ "zstd compression init level %d failed, root %llu inode %llu offset %llu",
+ workspace->req_level, btrfs_root_id(inode->root),
+ btrfs_ino(inode), start);
+ ret = -EIO;
+ goto out;
+ }
+
+ /* map in the first page of input data */
+ ret = btrfs_compress_filemap_get_folio(mapping, start, &in_folio);
+ if (ret < 0)
+ goto out;
+ cur_len = btrfs_calc_input_length(in_folio, orig_end, start);
+ workspace->in_buf.src = kmap_local_folio(in_folio, offset_in_folio(in_folio, start));
+ workspace->in_buf.pos = 0;
+ workspace->in_buf.size = cur_len;
+
+ /* Allocate and map in the output buffer */
+ out_folio = btrfs_alloc_compr_folio(fs_info);
+ if (out_folio == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ folios[nr_folios++] = out_folio;
+ workspace->out_buf.dst = folio_address(out_folio);
+ workspace->out_buf.pos = 0;
+ workspace->out_buf.size = min_t(size_t, max_out, min_folio_size);
+
+ while (1) {
+ size_t ret2;
+
+ ret2 = zstd_compress_stream(stream, &workspace->out_buf,
+ &workspace->in_buf);
+ if (unlikely(zstd_is_error(ret2))) {
+ btrfs_warn(fs_info,
+"zstd compression level %d failed, error %d root %llu inode %llu offset %llu",
+ workspace->req_level, zstd_get_error_code(ret2),
+ btrfs_root_id(inode->root), btrfs_ino(inode),
+ start);
+ ret = -EIO;
+ goto out;
+ }
+
+ /* Check to see if we are making it bigger */
+ if (tot_in + workspace->in_buf.pos > blocksize * 2 &&
+ tot_in + workspace->in_buf.pos <
+ tot_out + workspace->out_buf.pos) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ /* We've reached the end of our output range */
+ if (workspace->out_buf.pos >= max_out) {
+ tot_out += workspace->out_buf.pos;
+ ret = -E2BIG;
+ goto out;
+ }
+
+ /* Check if we need more output space */
+ if (workspace->out_buf.pos == workspace->out_buf.size) {
+ tot_out += min_folio_size;
+ max_out -= min_folio_size;
+ if (nr_folios == nr_dest_folios) {
+ ret = -E2BIG;
+ goto out;
+ }
+ out_folio = btrfs_alloc_compr_folio(fs_info);
+ if (out_folio == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ folios[nr_folios++] = out_folio;
+ workspace->out_buf.dst = folio_address(out_folio);
+ workspace->out_buf.pos = 0;
+ workspace->out_buf.size = min_t(size_t, max_out, min_folio_size);
+ }
+
+ /* We've reached the end of the input */
+ if (workspace->in_buf.pos >= len) {
+ tot_in += workspace->in_buf.pos;
+ break;
+ }
+
+ /* Check if we need more input */
+ if (workspace->in_buf.pos == workspace->in_buf.size) {
+ tot_in += workspace->in_buf.size;
+ kunmap_local(workspace->in_buf.src);
+ workspace->in_buf.src = NULL;
+ folio_put(in_folio);
+ start += cur_len;
+ len -= cur_len;
+ ret = btrfs_compress_filemap_get_folio(mapping, start, &in_folio);
+ if (ret < 0)
+ goto out;
+ cur_len = btrfs_calc_input_length(in_folio, orig_end, start);
+ workspace->in_buf.src = kmap_local_folio(in_folio,
+ offset_in_folio(in_folio, start));
+ workspace->in_buf.pos = 0;
+ workspace->in_buf.size = cur_len;
+ }
+ }
+ while (1) {
+ size_t ret2;
+
+ ret2 = zstd_end_stream(stream, &workspace->out_buf);
+ if (unlikely(zstd_is_error(ret2))) {
+ btrfs_err(fs_info,
+"zstd compression end level %d failed, error %d root %llu inode %llu offset %llu",
+ workspace->req_level, zstd_get_error_code(ret2),
+ btrfs_root_id(inode->root), btrfs_ino(inode),
+ start);
+ ret = -EIO;
+ goto out;
+ }
+ if (ret2 == 0) {
+ tot_out += workspace->out_buf.pos;
+ break;
+ }
+ if (workspace->out_buf.pos >= max_out) {
+ tot_out += workspace->out_buf.pos;
+ ret = -E2BIG;
+ goto out;
+ }
+
+ tot_out += min_folio_size;
+ max_out -= min_folio_size;
+ if (nr_folios == nr_dest_folios) {
+ ret = -E2BIG;
+ goto out;
+ }
+ out_folio = btrfs_alloc_compr_folio(fs_info);
+ if (out_folio == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ folios[nr_folios++] = out_folio;
+ workspace->out_buf.dst = folio_address(out_folio);
+ workspace->out_buf.pos = 0;
+ workspace->out_buf.size = min_t(size_t, max_out, min_folio_size);
+ }
+
+ if (tot_out >= tot_in) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ ret = 0;
+ *total_in = tot_in;
+ *total_out = tot_out;
+out:
+ *out_folios = nr_folios;
+ if (workspace->in_buf.src) {
+ kunmap_local(workspace->in_buf.src);
+ folio_put(in_folio);
+ }
+ return ret;
+}
+
+int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
+{
+ struct btrfs_fs_info *fs_info = cb_to_fs_info(cb);
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct folio **folios_in = cb->compressed_folios;
+ size_t srclen = cb->compressed_len;
+ zstd_dstream *stream;
+ int ret = 0;
+ const u32 blocksize = fs_info->sectorsize;
+ const unsigned int min_folio_size = btrfs_min_folio_size(fs_info);
+ unsigned long folio_in_index = 0;
+ unsigned long total_folios_in = DIV_ROUND_UP(srclen, min_folio_size);
+ unsigned long buf_start;
+ unsigned long total_out = 0;
+
+ stream = zstd_init_dstream(
+ ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
+ if (unlikely(!stream)) {
+ struct btrfs_inode *inode = cb->bbio.inode;
+
+ btrfs_err(inode->root->fs_info,
+ "zstd decompression init failed, root %llu inode %llu offset %llu",
+ btrfs_root_id(inode->root), btrfs_ino(inode), cb->start);
+ ret = -EIO;
+ goto done;
+ }
+
+ workspace->in_buf.src = kmap_local_folio(folios_in[folio_in_index], 0);
+ workspace->in_buf.pos = 0;
+ workspace->in_buf.size = min_t(size_t, srclen, min_folio_size);
+
+ workspace->out_buf.dst = workspace->buf;
+ workspace->out_buf.pos = 0;
+ workspace->out_buf.size = blocksize;
+
+ while (1) {
+ size_t ret2;
+
+ ret2 = zstd_decompress_stream(stream, &workspace->out_buf,
+ &workspace->in_buf);
+ if (unlikely(zstd_is_error(ret2))) {
+ struct btrfs_inode *inode = cb->bbio.inode;
+
+ btrfs_err(inode->root->fs_info,
+ "zstd decompression failed, error %d root %llu inode %llu offset %llu",
+ zstd_get_error_code(ret2), btrfs_root_id(inode->root),
+ btrfs_ino(inode), cb->start);
+ 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) {
+ kunmap_local(workspace->in_buf.src);
+ folio_in_index++;
+ if (unlikely(folio_in_index >= total_folios_in)) {
+ workspace->in_buf.src = NULL;
+ ret = -EIO;
+ goto done;
+ }
+ srclen -= min_folio_size;
+ workspace->in_buf.src =
+ kmap_local_folio(folios_in[folio_in_index], 0);
+ workspace->in_buf.pos = 0;
+ workspace->in_buf.size = min_t(size_t, srclen, min_folio_size);
+ }
+ }
+ ret = 0;
+done:
+ if (workspace->in_buf.src)
+ kunmap_local(workspace->in_buf.src);
+ return ret;
+}
+
+int zstd_decompress(struct list_head *ws, const u8 *data_in,
+ struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
+ size_t destlen)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct btrfs_fs_info *fs_info = btrfs_sb(folio_inode(dest_folio)->i_sb);
+ const u32 sectorsize = fs_info->sectorsize;
+ zstd_dstream *stream;
+ int ret = 0;
+ unsigned long to_copy = 0;
+
+ stream = zstd_init_dstream(
+ ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
+ if (unlikely(!stream)) {
+ struct btrfs_inode *inode = folio_to_inode(dest_folio);
+
+ btrfs_err(inode->root->fs_info,
+ "zstd decompression init failed, root %llu inode %llu offset %llu",
+ btrfs_root_id(inode->root), btrfs_ino(inode),
+ folio_pos(dest_folio));
+ ret = -EIO;
+ goto finish;
+ }
+
+ 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 = sectorsize;
+
+ /*
+ * Since both input and output buffers should not exceed one sector,
+ * one call should end the decompression.
+ */
+ ret = zstd_decompress_stream(stream, &workspace->out_buf, &workspace->in_buf);
+ if (unlikely(zstd_is_error(ret))) {
+ struct btrfs_inode *inode = folio_to_inode(dest_folio);
+
+ btrfs_err(inode->root->fs_info,
+ "zstd decompression failed, error %d root %llu inode %llu offset %llu",
+ zstd_get_error_code(ret), btrfs_root_id(inode->root),
+ btrfs_ino(inode), folio_pos(dest_folio));
+ goto finish;
+ }
+ to_copy = workspace->out_buf.pos;
+ memcpy_to_folio(dest_folio, dest_pgoff, workspace->out_buf.dst, to_copy);
+finish:
+ /* Error or early end. */
+ if (unlikely(to_copy < destlen)) {
+ ret = -EIO;
+ folio_zero_range(dest_folio, dest_pgoff + to_copy, destlen - to_copy);
+ }
+ return ret;
+}
+
+const struct btrfs_compress_levels btrfs_zstd_compress = {
+ .min_level = ZSTD_BTRFS_MIN_LEVEL,
+ .max_level = ZSTD_BTRFS_MAX_LEVEL,
+ .default_level = ZSTD_BTRFS_DEFAULT_LEVEL,
+};
generated by cgit (git 2.34.1) at 2025-12-21 21:38:49 +0000