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linux/fs/btrfs/zlib.c
David Sterba be9438f077 btrfs: enhance compression error messages 
Add more verbose and specific messages to all main error points in
compression code for all algorithms. Currently there's no way to know
which inode is affected or where in the data errors happened.

The messages follow a common format:

- what happened
- error code if relevant
- root and inode
- additional data like offsets or lengths

There's no helper for the messages as they differ in some details and
that would be cumbersome to generalize to a single function. As all the
errors are "almost never happens" there are the unlikely annotations
done as compression is hot path.

Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:52:25 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2008 Oracle. All rights reserved.
*
* Based on jffs2 zlib code:
* Copyright © 2001-2007 Red Hat, Inc.
* Created by David Woodhouse <dwmw2@infradead.org>
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/zlib.h>
#include <linux/zutil.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/pagemap.h>
#include <linux/bio.h>
#include <linux/refcount.h>
#include "btrfs_inode.h"
#include "compression.h"
/* workspace buffer size for s390 zlib hardware support */
#define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
struct workspace {
z_stream strm;
char *buf;
unsigned int buf_size;
struct list_head list;
int level;
};
static struct workspace_manager wsm;
struct list_head *zlib_get_workspace(unsigned int level)
{
struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
struct workspace *workspace = list_entry(ws, struct workspace, list);
workspace->level = level;
return ws;
}
void zlib_free_workspace(struct list_head *ws)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
kvfree(workspace->strm.workspace);
kfree(workspace->buf);
kfree(workspace);
}
struct list_head *zlib_alloc_workspace(unsigned int level)
{
struct workspace *workspace;
int workspacesize;
workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
if (!workspace)
return ERR_PTR(-ENOMEM);
workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
zlib_inflate_workspacesize());
workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL | __GFP_NOWARN);
workspace->level = level;
workspace->buf = NULL;
/*
* In case of s390 zlib hardware support, allocate lager workspace
* buffer. If allocator fails, fall back to a single page buffer.
*/
if (zlib_deflate_dfltcc_enabled()) {
workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
__GFP_NOMEMALLOC | __GFP_NORETRY |
__GFP_NOWARN | GFP_NOIO);
workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
}
if (!workspace->buf) {
workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
workspace->buf_size = PAGE_SIZE;
}
if (!workspace->strm.workspace || !workspace->buf)
goto fail;
INIT_LIST_HEAD(&workspace->list);
return &workspace->list;
fail:
zlib_free_workspace(&workspace->list);
return ERR_PTR(-ENOMEM);
}
int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
u64 start, struct folio **folios, unsigned long *out_folios,
unsigned long *total_in, unsigned long *total_out)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret;
char *data_in = NULL;
char *cfolio_out;
int nr_folios = 0;
struct folio *in_folio = NULL;
struct folio *out_folio = NULL;
unsigned long bytes_left;
unsigned int in_buf_folios;
unsigned long len = *total_out;
unsigned long nr_dest_folios = *out_folios;
const unsigned long max_out = nr_dest_folios * PAGE_SIZE;
*out_folios = 0;
*total_out = 0;
*total_in = 0;
ret = zlib_deflateInit(&workspace->strm, workspace->level);
if (unlikely(ret != Z_OK)) {
struct btrfs_inode *inode = BTRFS_I(mapping->host);
btrfs_err(inode->root->fs_info,
"zlib compression init failed, error %d root %llu inode %llu offset %llu",
ret, btrfs_root_id(inode->root), btrfs_ino(inode), start);
ret = -EIO;
goto out;
}
workspace->strm.total_in = 0;
workspace->strm.total_out = 0;
out_folio = btrfs_alloc_compr_folio();
if (out_folio == NULL) {
ret = -ENOMEM;
goto out;
}
cfolio_out = folio_address(out_folio);
folios[0] = out_folio;
nr_folios = 1;
workspace->strm.next_in = workspace->buf;
workspace->strm.avail_in = 0;
workspace->strm.next_out = cfolio_out;
workspace->strm.avail_out = PAGE_SIZE;
while (workspace->strm.total_in < len) {
/*
* Get next input pages and copy the contents to
* the workspace buffer if required.
*/
if (workspace->strm.avail_in == 0) {
bytes_left = len - workspace->strm.total_in;
in_buf_folios = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
workspace->buf_size / PAGE_SIZE);
if (in_buf_folios > 1) {
int i;
for (i = 0; i < in_buf_folios; i++) {
if (data_in) {
kunmap_local(data_in);
folio_put(in_folio);
data_in = NULL;
}
ret = btrfs_compress_filemap_get_folio(mapping,
start, &in_folio);
if (ret < 0)
goto out;
data_in = kmap_local_folio(in_folio, 0);
copy_page(workspace->buf + i * PAGE_SIZE,
data_in);
start += PAGE_SIZE;
}
workspace->strm.next_in = workspace->buf;
} else {
if (data_in) {
kunmap_local(data_in);
folio_put(in_folio);
data_in = NULL;
}
ret = btrfs_compress_filemap_get_folio(mapping,
start, &in_folio);
if (ret < 0)
goto out;
data_in = kmap_local_folio(in_folio, 0);
start += PAGE_SIZE;
workspace->strm.next_in = data_in;
}
workspace->strm.avail_in = min(bytes_left,
(unsigned long) workspace->buf_size);
}
ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
if (unlikely(ret != Z_OK)) {
struct btrfs_inode *inode = BTRFS_I(mapping->host);
btrfs_warn(inode->root->fs_info,
"zlib compression failed, error %d root %llu inode %llu offset %llu",
ret, btrfs_root_id(inode->root), btrfs_ino(inode),
start);
zlib_deflateEnd(&workspace->strm);
ret = -EIO;
goto out;
}
/* we're making it bigger, give up */
if (workspace->strm.total_in > 8192 &&
workspace->strm.total_in <
workspace->strm.total_out) {
ret = -E2BIG;
goto out;
}
/* we need another page for writing out. Test this
* before the total_in so we will pull in a new page for
* the stream end if required
*/
if (workspace->strm.avail_out == 0) {
if (nr_folios == nr_dest_folios) {
ret = -E2BIG;
goto out;
}
out_folio = btrfs_alloc_compr_folio();
if (out_folio == NULL) {
ret = -ENOMEM;
goto out;
}
cfolio_out = folio_address(out_folio);
folios[nr_folios] = out_folio;
nr_folios++;
workspace->strm.avail_out = PAGE_SIZE;
workspace->strm.next_out = cfolio_out;
}
/* we're all done */
if (workspace->strm.total_in >= len)
break;
if (workspace->strm.total_out > max_out)
break;
}
workspace->strm.avail_in = 0;
/*
* Call deflate with Z_FINISH flush parameter providing more output
* space but no more input data, until it returns with Z_STREAM_END.
*/
while (ret != Z_STREAM_END) {
ret = zlib_deflate(&workspace->strm, Z_FINISH);
if (ret == Z_STREAM_END)
break;
if (ret != Z_OK && ret != Z_BUF_ERROR) {
zlib_deflateEnd(&workspace->strm);
ret = -EIO;
goto out;
} else if (workspace->strm.avail_out == 0) {
/* Get another folio for the stream end. */
if (nr_folios == nr_dest_folios) {
ret = -E2BIG;
goto out;
}
out_folio = btrfs_alloc_compr_folio();
if (out_folio == NULL) {
ret = -ENOMEM;
goto out;
}
cfolio_out = folio_address(out_folio);
folios[nr_folios] = out_folio;
nr_folios++;
workspace->strm.avail_out = PAGE_SIZE;
workspace->strm.next_out = cfolio_out;
}
}
zlib_deflateEnd(&workspace->strm);
if (workspace->strm.total_out >= workspace->strm.total_in) {
ret = -E2BIG;
goto out;
}
ret = 0;
*total_out = workspace->strm.total_out;
*total_in = workspace->strm.total_in;
out:
*out_folios = nr_folios;
if (data_in) {
kunmap_local(data_in);
folio_put(in_folio);
}
return ret;
}
int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret = 0, ret2;
int wbits = MAX_WBITS;
char *data_in;
size_t total_out = 0;
unsigned long folio_in_index = 0;
size_t srclen = cb->compressed_len;
unsigned long total_folios_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
unsigned long buf_start;
struct folio **folios_in = cb->compressed_folios;
data_in = kmap_local_folio(folios_in[folio_in_index], 0);
workspace->strm.next_in = data_in;
workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
workspace->strm.total_in = 0;
workspace->strm.total_out = 0;
workspace->strm.next_out = workspace->buf;
workspace->strm.avail_out = workspace->buf_size;
/* If it's deflate, and it's got no preset dictionary, then
we can tell zlib to skip the adler32 check. */
if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
((data_in[0] & 0x0f) == Z_DEFLATED) &&
!(((data_in[0]<<8) + data_in[1]) % 31)) {
wbits = -((data_in[0] >> 4) + 8);
workspace->strm.next_in += 2;
workspace->strm.avail_in -= 2;
}
ret = zlib_inflateInit2(&workspace->strm, wbits);
if (unlikely(ret != Z_OK)) {
struct btrfs_inode *inode = cb->bbio.inode;
kunmap_local(data_in);
btrfs_err(inode->root->fs_info,
"zlib decompression init failed, error %d root %llu inode %llu offset %llu",
ret, btrfs_root_id(inode->root), btrfs_ino(inode), cb->start);
return -EIO;
}
while (workspace->strm.total_in < srclen) {
ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END)
break;
buf_start = total_out;
total_out = workspace->strm.total_out;
/* we didn't make progress in this inflate call, we're done */
if (buf_start == total_out)
break;
ret2 = btrfs_decompress_buf2page(workspace->buf,
total_out - buf_start, cb, buf_start);
if (ret2 == 0) {
ret = 0;
goto done;
}
workspace->strm.next_out = workspace->buf;
workspace->strm.avail_out = workspace->buf_size;
if (workspace->strm.avail_in == 0) {
unsigned long tmp;
kunmap_local(data_in);
folio_in_index++;
if (folio_in_index >= total_folios_in) {
data_in = NULL;
break;
}
data_in = kmap_local_folio(folios_in[folio_in_index], 0);
workspace->strm.next_in = data_in;
tmp = srclen - workspace->strm.total_in;
workspace->strm.avail_in = min(tmp, PAGE_SIZE);
}
}
if (unlikely(ret != Z_STREAM_END)) {
btrfs_err(cb->bbio.inode->root->fs_info,
"zlib decompression failed, error %d root %llu inode %llu offset %llu",
ret, btrfs_root_id(cb->bbio.inode->root),
btrfs_ino(cb->bbio.inode), cb->start);
ret = -EIO;
} else {
ret = 0;
}
done:
zlib_inflateEnd(&workspace->strm);
if (data_in)
kunmap_local(data_in);
return ret;
}
int zlib_decompress(struct list_head *ws, const u8 *data_in,
struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
size_t destlen)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret = 0;
int wbits = MAX_WBITS;
unsigned long to_copy;
workspace->strm.next_in = data_in;
workspace->strm.avail_in = srclen;
workspace->strm.total_in = 0;
workspace->strm.next_out = workspace->buf;
workspace->strm.avail_out = workspace->buf_size;
workspace->strm.total_out = 0;
/* If it's deflate, and it's got no preset dictionary, then
we can tell zlib to skip the adler32 check. */
if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
((data_in[0] & 0x0f) == Z_DEFLATED) &&
!(((data_in[0]<<8) + data_in[1]) % 31)) {
wbits = -((data_in[0] >> 4) + 8);
workspace->strm.next_in += 2;
workspace->strm.avail_in -= 2;
}
ret = zlib_inflateInit2(&workspace->strm, wbits);
if (unlikely(ret != Z_OK)) {
struct btrfs_inode *inode = BTRFS_I(dest_page->mapping->host);
btrfs_err(inode->root->fs_info,
"zlib decompression init failed, error %d root %llu inode %llu offset %llu",
ret, btrfs_root_id(inode->root), btrfs_ino(inode),
page_offset(dest_page));
return -EIO;
}
/*
* Everything (in/out buf) should be at most one sector, there should
* be no need to switch any input/output buffer.
*/
ret = zlib_inflate(&workspace->strm, Z_FINISH);
to_copy = min(workspace->strm.total_out, destlen);
if (ret != Z_STREAM_END)
goto out;
memcpy_to_page(dest_page, dest_pgoff, workspace->buf, to_copy);
out:
if (unlikely(to_copy != destlen)) {
struct btrfs_inode *inode = BTRFS_I(dest_page->mapping->host);
btrfs_err(inode->root->fs_info,
"zlib decompression failed, error %d root %llu inode %llu offset %llu decompressed %lu expected %zu",
ret, btrfs_root_id(inode->root), btrfs_ino(inode),
page_offset(dest_page), to_copy, destlen);
ret = -EIO;
} else {
ret = 0;
}
zlib_inflateEnd(&workspace->strm);
if (unlikely(to_copy < destlen))
memzero_page(dest_page, dest_pgoff + to_copy, destlen - to_copy);
return ret;
}
const struct btrfs_compress_op btrfs_zlib_compress = {
.workspace_manager = &wsm,
.max_level = 9,
.default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
};
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