v4.19.13 snapshot.
diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
new file mode 100644
index 0000000..af6ec59
--- /dev/null
+++ b/fs/btrfs/zstd.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ */
+
+#include <linux/bio.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/refcount.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/zstd.h>
+#include "compression.h"
+
+#define ZSTD_BTRFS_MAX_WINDOWLOG 17
+#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
+#define ZSTD_BTRFS_DEFAULT_LEVEL 3
+
+static ZSTD_parameters zstd_get_btrfs_parameters(size_t src_len)
+{
+ ZSTD_parameters params = ZSTD_getParams(ZSTD_BTRFS_DEFAULT_LEVEL,
+ src_len, 0);
+
+ 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;
+ struct list_head list;
+ ZSTD_inBuffer in_buf;
+ ZSTD_outBuffer out_buf;
+};
+
+static 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);
+}
+
+static struct list_head *zstd_alloc_workspace(void)
+{
+ ZSTD_parameters params =
+ zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);
+ struct workspace *workspace;
+
+ workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
+ if (!workspace)
+ return ERR_PTR(-ENOMEM);
+
+ workspace->size = max_t(size_t,
+ ZSTD_CStreamWorkspaceBound(params.cParams),
+ ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));
+ workspace->mem = kvmalloc(workspace->size, GFP_KERNEL);
+ workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!workspace->mem || !workspace->buf)
+ goto fail;
+
+ INIT_LIST_HEAD(&workspace->list);
+
+ return &workspace->list;
+fail:
+ zstd_free_workspace(&workspace->list);
+ return ERR_PTR(-ENOMEM);
+}
+
+static int zstd_compress_pages(struct list_head *ws,
+ struct address_space *mapping,
+ u64 start,
+ struct page **pages,
+ unsigned long *out_pages,
+ unsigned long *total_in,
+ unsigned long *total_out)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ ZSTD_CStream *stream;
+ int ret = 0;
+ int nr_pages = 0;
+ struct page *in_page = NULL; /* The current page to read */
+ struct page *out_page = NULL; /* The current page to write to */
+ unsigned long tot_in = 0;
+ unsigned long tot_out = 0;
+ unsigned long len = *total_out;
+ const unsigned long nr_dest_pages = *out_pages;
+ unsigned long max_out = nr_dest_pages * PAGE_SIZE;
+ ZSTD_parameters params = zstd_get_btrfs_parameters(len);
+
+ *out_pages = 0;
+ *total_out = 0;
+ *total_in = 0;
+
+ /* Initialize the stream */
+ stream = ZSTD_initCStream(params, len, workspace->mem,
+ workspace->size);
+ if (!stream) {
+ pr_warn("BTRFS: ZSTD_initCStream failed\n");
+ ret = -EIO;
+ goto out;
+ }
+
+ /* map in the first page of input data */
+ in_page = find_get_page(mapping, start >> PAGE_SHIFT);
+ workspace->in_buf.src = kmap(in_page);
+ workspace->in_buf.pos = 0;
+ workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
+
+
+ /* Allocate and map in the output buffer */
+ out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_page == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ pages[nr_pages++] = out_page;
+ workspace->out_buf.dst = kmap(out_page);
+ workspace->out_buf.pos = 0;
+ workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
+
+ while (1) {
+ size_t ret2;
+
+ ret2 = ZSTD_compressStream(stream, &workspace->out_buf,
+ &workspace->in_buf);
+ if (ZSTD_isError(ret2)) {
+ pr_debug("BTRFS: ZSTD_compressStream returned %d\n",
+ ZSTD_getErrorCode(ret2));
+ ret = -EIO;
+ goto out;
+ }
+
+ /* Check to see if we are making it bigger */
+ if (tot_in + workspace->in_buf.pos > 8192 &&
+ 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 += PAGE_SIZE;
+ max_out -= PAGE_SIZE;
+ kunmap(out_page);
+ if (nr_pages == nr_dest_pages) {
+ out_page = NULL;
+ ret = -E2BIG;
+ goto out;
+ }
+ out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_page == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ pages[nr_pages++] = out_page;
+ workspace->out_buf.dst = kmap(out_page);
+ workspace->out_buf.pos = 0;
+ workspace->out_buf.size = min_t(size_t, max_out,
+ PAGE_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 += PAGE_SIZE;
+ kunmap(in_page);
+ put_page(in_page);
+
+ start += PAGE_SIZE;
+ len -= PAGE_SIZE;
+ in_page = find_get_page(mapping, start >> PAGE_SHIFT);
+ workspace->in_buf.src = kmap(in_page);
+ workspace->in_buf.pos = 0;
+ workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
+ }
+ }
+ while (1) {
+ size_t ret2;
+
+ ret2 = ZSTD_endStream(stream, &workspace->out_buf);
+ if (ZSTD_isError(ret2)) {
+ pr_debug("BTRFS: ZSTD_endStream returned %d\n",
+ ZSTD_getErrorCode(ret2));
+ 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 += PAGE_SIZE;
+ max_out -= PAGE_SIZE;
+ kunmap(out_page);
+ if (nr_pages == nr_dest_pages) {
+ out_page = NULL;
+ ret = -E2BIG;
+ goto out;
+ }
+ out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_page == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ pages[nr_pages++] = out_page;
+ workspace->out_buf.dst = kmap(out_page);
+ workspace->out_buf.pos = 0;
+ workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
+ }
+
+ if (tot_out >= tot_in) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ ret = 0;
+ *total_in = tot_in;
+ *total_out = tot_out;
+out:
+ *out_pages = nr_pages;
+ /* Cleanup */
+ if (in_page) {
+ kunmap(in_page);
+ put_page(in_page);
+ }
+ if (out_page)
+ kunmap(out_page);
+ return ret;
+}
+
+static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct page **pages_in = cb->compressed_pages;
+ u64 disk_start = cb->start;
+ struct bio *orig_bio = cb->orig_bio;
+ size_t srclen = cb->compressed_len;
+ ZSTD_DStream *stream;
+ int ret = 0;
+ unsigned long page_in_index = 0;
+ unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
+ unsigned long buf_start;
+ unsigned long total_out = 0;
+
+ stream = ZSTD_initDStream(
+ ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
+ if (!stream) {
+ pr_debug("BTRFS: ZSTD_initDStream failed\n");
+ ret = -EIO;
+ goto done;
+ }
+
+ workspace->in_buf.src = kmap(pages_in[page_in_index]);
+ 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,
+ buf_start, total_out, disk_start, orig_bio);
+ 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(pages_in[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 = kmap(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(orig_bio);
+done:
+ if (workspace->in_buf.src)
+ kunmap(pages_in[page_in_index]);
+ return ret;
+}
+
+static 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;
+ char *kaddr;
+
+ 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);
+
+ kaddr = kmap_atomic(dest_page);
+ memcpy(kaddr + pg_offset, workspace->out_buf.dst + buf_offset,
+ bytes);
+ kunmap_atomic(kaddr);
+
+ pg_offset += bytes;
+ }
+ ret = 0;
+finish:
+ if (pg_offset < destlen) {
+ kaddr = kmap_atomic(dest_page);
+ memset(kaddr + pg_offset, 0, destlen - pg_offset);
+ kunmap_atomic(kaddr);
+ }
+ return ret;
+}
+
+static void zstd_set_level(struct list_head *ws, unsigned int type)
+{
+}
+
+const struct btrfs_compress_op btrfs_zstd_compress = {
+ .alloc_workspace = zstd_alloc_workspace,
+ .free_workspace = zstd_free_workspace,
+ .compress_pages = zstd_compress_pages,
+ .decompress_bio = zstd_decompress_bio,
+ .decompress = zstd_decompress,
+ .set_level = zstd_set_level,
+};