mirror of
https://github.com/facebook/zstd.git
synced 2025-08-08 17:22:10 +03:00
Add fs/btrfs/zstd.c
This commit is contained in:
Nick Terrell
414
contrib/linux-kernel/fs/btrfs/zstd.c
Normal file
414
contrib/linux-kernel/fs/btrfs/zstd.c
Normal file
@@ -0,0 +1,414 @@
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <linux/pagemap.h>
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#include <linux/bio.h>
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#include <linux/zstd.h>
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#include "compression.h"
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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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static ZSTD_parameters zstd_get_btrfs_parameters(size_t src_len)
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{
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ZSTD_parameters params = ZSTD_getParams(3, src_len, 0);
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BUG_ON(src_len > ZSTD_BTRFS_MAX_INPUT);
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BUG_ON(params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG);
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params.fParams.checksumFlag = 1;
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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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struct list_head list;
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};
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static 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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vfree(workspace->mem);
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kfree(workspace->buf);
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kfree(workspace);
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}
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static struct list_head *zstd_alloc_workspace(void)
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{
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ZSTD_parameters params = zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);
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struct workspace *workspace;
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workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
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if (!workspace) return ERR_PTR(-ENOMEM);
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workspace->size = max_t(size_t, ZSTD_CStreamWorkspaceBound(params.cParams),
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ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));
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workspace->mem = vmalloc(workspace->size);
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workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS);
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if (!workspace->mem || !workspace->buf) goto fail;
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INIT_LIST_HEAD(&workspace->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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static int zstd_compress_pages(struct list_head *ws,
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struct address_space *mapping,
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u64 start, unsigned long len,
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struct page **pages,
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unsigned long nr_dest_pages,
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unsigned long *out_pages,
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unsigned long *total_in,
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unsigned long *total_out,
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unsigned long max_out)
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{
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struct workspace *workspace = list_entry(ws, struct workspace, list);
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ZSTD_parameters params = zstd_get_btrfs_parameters(len);
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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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ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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unsigned long tot_in = 0;
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unsigned long tot_out = 0;
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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_createCStream(params, len, workspace->mem, workspace->size);
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if (!stream) {
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pr_warn("BTRFS: ZSTD_createStream 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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in_buf.src = kmap(in_page);
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in_buf.pos = 0;
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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 | __GFP_HIGHMEM);
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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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out_buf.dst = kmap(out_page);
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out_buf.pos = 0;
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out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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while (1) {
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const size_t rc = ZSTD_compressStream(stream, &out_buf, &in_buf);
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if (ZSTD_isError(rc)) {
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pr_debug("BTRFS: ZSTD_compressStream returned %d\n",
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ZSTD_getErrorCode(rc));
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ret = -EIO;
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goto out;
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}
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/* Check to see if we are making it bigger */
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if (tot_in + in_buf.pos > 8192 &&
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tot_in + in_buf.pos <
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tot_out + out_buf.pos) {
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ret = -E2BIG;
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goto out;
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}
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/* We've reached the end of our output range */
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if (out_buf.pos >= max_out) {
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tot_out += out_buf.pos;
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ret = -E2BIG;
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goto out;
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}
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/* Check if we need more output space */
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if (out_buf.pos == out_buf.size) {
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tot_out += PAGE_SIZE;
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max_out -= PAGE_SIZE;
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kunmap(out_page);
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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 | __GFP_HIGHMEM);
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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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out_buf.dst = kmap(out_page);
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out_buf.pos = 0;
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out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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}
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/* We've reached the end of the input */
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if (in_buf.pos >= len) {
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tot_in += in_buf.pos;
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break;
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}
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/* Check if we need more input */
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if (in_buf.pos == in_buf.size) {
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tot_in += PAGE_SIZE;
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kunmap(in_page);
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put_page(in_page);
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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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in_buf.src = kmap(in_page);
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in_buf.pos = 0;
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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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const size_t rc = ZSTD_endStream(stream, &out_buf);
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if (ZSTD_isError(rc)) {
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pr_debug("BTRFS: ZSTD_endStream returned %d\n",
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ZSTD_getErrorCode(rc));
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ret = -EIO;
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goto out;
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}
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if (rc == 0) {
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tot_out += out_buf.pos;
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break;
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}
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if (out_buf.pos >= max_out) {
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tot_out += out_buf.pos;
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ret = -E2BIG;
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goto out;
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}
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tot_out += PAGE_SIZE;
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max_out -= PAGE_SIZE;
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kunmap(out_page);
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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 | __GFP_HIGHMEM);
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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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out_buf.dst = kmap(out_page);
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out_buf.pos = 0;
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out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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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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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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kunmap(in_page);
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put_page(in_page);
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}
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if (out_page) { kunmap(out_page); }
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return ret;
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}
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static int zstd_decompress_biovec(struct list_head *ws, struct page **pages_in,
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u64 disk_start,
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struct bio_vec *bvec,
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int vcnt,
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size_t srclen)
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{
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struct workspace *workspace = list_entry(ws, struct workspace, list);
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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 page_out_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 pg_offset;
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unsigned long total_out = 0;
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ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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stream = ZSTD_createDStream(
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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_createDStream failed\n");
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ret = -EIO;
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goto done;
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}
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in_buf.src = kmap(pages_in[page_in_index]);
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in_buf.pos = 0;
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in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
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out_buf.dst = workspace->buf;
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out_buf.pos = 0;
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out_buf.size = PAGE_SIZE;
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pg_offset = 0;
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while (1) {
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const size_t rc = ZSTD_decompressStream(stream, &out_buf, &in_buf);
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if (zstd_is_error(rc)) {
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pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
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zstd_get_error_code(rc));
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ret = -EIO;
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goto done;
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}
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buf_start = total_out;
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total_out += out_buf.pos;
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out_buf.pos = 0;
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{
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int ret2 = btrfs_decompress_buf2page(out_buf.dst, buf_start,
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total_out, disk_start, bvec, vcnt,
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&page_out_index, &pg_offset);
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if (ret2 == 0) {
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break;
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}
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}
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if (in_buf.pos >= srclen) {
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break;
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}
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/* Check if we've hit the end of a frame */
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if (rc == 0) {
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break;
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}
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if (in_buf.pos == in_buf.size) {
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kunmap(pages_in[page_in_index++]);
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if (page_in_index >= total_pages_in) {
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in_buf.src = NULL;
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ret = -EIO;
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goto done;
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}
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srclen -= PAGE_SIZE;
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in_buf.src = kmap(pages_in[page_in_index]);
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in_buf.pos = 0;
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in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
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}
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}
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btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset);
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ret = 0;
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done:
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if (in_buf.src) { kunmap(pages_in[page_in_index]); }
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return ret;
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}
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static int zstd_decompress(struct list_head *ws, unsigned char *data_in,
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struct page *dest_page,
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unsigned long start_byte,
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size_t srclen, size_t destlen)
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{
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struct workspace *workspace = list_entry(ws, struct workspace, list);
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ZSTD_DStream *stream;
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int ret = 0;
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ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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unsigned long total_out = 0;
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unsigned long pg_offset = 0;
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char *kaddr;
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stream = ZSTD_createDStream(
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ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
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if (!stream) {
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pr_warn("BTRFS: ZSTD_createDStream failed\n");
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ret = -EIO;
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goto finish;
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}
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destlen = min_t(size_t, destlen, PAGE_SIZE);
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in_buf.src = data_in;
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in_buf.pos = 0;
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in_buf.size = srclen;
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out_buf.dst = workspace->buf;
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out_buf.pos = 0;
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out_buf.size = PAGE_SIZE;
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ret = 1;
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while (pg_offset < destlen && in_buf.pos < in_buf.size) {
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unsigned long buf_start;
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unsigned long buf_offset;
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unsigned long bytes;
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/* Check if the frame is over and we still need more input */
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if (ret == 0) {
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pr_debug("BTRFS: ZSTD_decompressStream frame ended to early\n");
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ret = -EIO;
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goto finish;
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}
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{
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const size_t rc = ZSTD_decompressStream(stream, &out_buf, &in_buf);
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if (ZSTD_isError(rc)) {
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pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
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ZSTD_getErrorCode(rc));
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ret = -EIO;
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goto finish;
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}
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ret = rc > 0;
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}
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buf_start = total_out;
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total_out += out_buf.pos;
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out_buf.pos = 0;
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if (total_out <= start_byte) {
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continue;
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}
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if (total_out > start_byte && buf_start < start_byte) {
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buf_offset = start_byte - buf_start;
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} else {
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buf_offset = 0;
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}
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bytes = min_t(unsigned long, destlen - pg_offset,
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out_buf.size - buf_offset);
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kaddr = kmap_atomic(dest_page);
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memcpy(kaddr + pg_offset, out_buf.dst + buf_offset, bytes);
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kunmap_atomic(kaddr);
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pg_offset += bytes;
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}
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ret = 0;
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finish:
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if (pg_offset < destlen) {
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kaddr = kmap_atomic(dest_page);
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memset(kaddr + pg_offset, 0, destlen - pg_offset);
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kunmap_atomic(kaddr);
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}
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return ret;
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}
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const struct btrfs_compress_op btrfs_zstd_compress = {
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.alloc_workspace = zstd_alloc_workspace,
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.free_workspace = zstd_free_workspace,
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.compress_pages = zstd_compress_pages,
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.decompress_biovec = zstd_decompress_biovec,
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.decompress = zstd_decompress,
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};
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