From e01a83e12604aa2f8d4ab359ec44e341a2248b4a Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 22 Jan 2024 15:39:01 -0800 Subject: Revert "btrfs: zstd: fix and simplify the inline extent decompression" This reverts commit 1e7f6def8b2370ecefb54b3c8f390ff894b0c51b. It causes my machine to not even boot, and Klara Modin reports that the cause is that small zstd-compressed files return garbage when read. Reported-by: Klara Modin Link: https://lore.kernel.org/linux-btrfs/CABq1_vj4GpUeZpVG49OHCo-3sdbe2-2ROcu_xDvUG-6-5zPRXg@mail.gmail.com/ Reported-and-bisected-by: Linus Torvalds Acked-by: David Sterba Cc: Qu Wenruo Signed-off-by: Linus Torvalds --- fs/btrfs/zstd.c | 75 ++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 53 insertions(+), 22 deletions(-) (limited to 'fs/btrfs/zstd.c') diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c index 346c46d88d07..0d66db8bc1d4 100644 --- a/fs/btrfs/zstd.c +++ b/fs/btrfs/zstd.c @@ -20,7 +20,6 @@ #include "misc.h" #include "compression.h" #include "ctree.h" -#include "super.h" #define ZSTD_BTRFS_MAX_WINDOWLOG 17 #define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG) @@ -619,48 +618,80 @@ done: } int zstd_decompress(struct list_head *ws, const u8 *data_in, - struct page *dest_page, unsigned long dest_pgoff, size_t srclen, + struct page *dest_page, unsigned long start_byte, size_t srclen, size_t destlen) { struct workspace *workspace = list_entry(ws, struct workspace, list); - struct btrfs_fs_info *fs_info = btrfs_sb(dest_page->mapping->host->i_sb); - const u32 sectorsize = fs_info->sectorsize; zstd_dstream *stream; int ret = 0; - unsigned long to_copy = 0; + size_t ret2; + unsigned long total_out = 0; + unsigned long pg_offset = 0; stream = zstd_init_dstream( ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size); if (!stream) { pr_warn("BTRFS: zstd_init_dstream 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 = 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 (zstd_is_error(ret)) { - pr_warn_ratelimited("BTRFS: zstd_decompress_stream return %d\n", - zstd_get_error_code(ret)); - goto finish; + 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_decompress_stream ended early\n"); + ret = -EIO; + goto finish; + } + ret2 = zstd_decompress_stream(stream, &workspace->out_buf, + &workspace->in_buf); + if (zstd_is_error(ret2)) { + pr_debug("BTRFS: zstd_decompress_stream returned %d\n", + zstd_get_error_code(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; } - to_copy = workspace->out_buf.pos; - memcpy_to_page(dest_page, dest_pgoff + to_copy, workspace->out_buf.dst, to_copy); + ret = 0; finish: - /* Error or early end. */ - if (unlikely(to_copy < destlen)) { - ret = -EIO; - memzero_page(dest_page, dest_pgoff + to_copy, destlen - to_copy); + if (pg_offset < destlen) { + memzero_page(dest_page, pg_offset, destlen - pg_offset); } return ret; } -- cgit v1.2.3