Commit 55276e14 authored by David Sterba's avatar David Sterba
Browse files

Revert "btrfs: compression: drop kmap/kunmap from zlib" 

This reverts commit 696ab562.

The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.

Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839


Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 56ee254d

fs/btrfs/zlib.c

+25 −11
Original line number Diff line number Diff line
@@ -126,7 +126,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 
		ret = -ENOMEM;

		goto out;

	}

	cpage_out = page_address(out_page);

	cpage_out = kmap(out_page);

	pages[0] = out_page;

	nr_pages = 1;
@@ -148,22 +148,26 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 
				int i;



				for (i = 0; i < in_buf_pages; i++) {

					if (in_page)

					if (in_page) {

						kunmap(in_page);

						put_page(in_page);

					}

					in_page = find_get_page(mapping,

								start >> PAGE_SHIFT);

					data_in = page_address(in_page);

					data_in = kmap(in_page);

					memcpy(workspace->buf + i * PAGE_SIZE,

					       data_in, PAGE_SIZE);

					start += PAGE_SIZE;

				}

				workspace->strm.next_in = workspace->buf;

			} else {

				if (in_page)

				if (in_page) {

					kunmap(in_page);

					put_page(in_page);

				}

				in_page = find_get_page(mapping,

							start >> PAGE_SHIFT);

				data_in = page_address(in_page);

				data_in = kmap(in_page);

				start += PAGE_SIZE;

				workspace->strm.next_in = data_in;

			}
@@ -192,6 +196,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 
		 * the stream end if required

		 */

		if (workspace->strm.avail_out == 0) {

			kunmap(out_page);

			if (nr_pages == nr_dest_pages) {

				out_page = NULL;

				ret = -E2BIG;
@@ -202,7 +207,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 
				ret = -ENOMEM;

				goto out;

			}

			cpage_out = page_address(out_page);

			cpage_out = kmap(out_page);

			pages[nr_pages] = out_page;

			nr_pages++;

			workspace->strm.avail_out = PAGE_SIZE;
@@ -229,6 +234,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 
			goto out;

		} else if (workspace->strm.avail_out == 0) {

			/* get another page for the stream end */

			kunmap(out_page);

			if (nr_pages == nr_dest_pages) {

				out_page = NULL;

				ret = -E2BIG;
@@ -239,7 +245,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 
				ret = -ENOMEM;

				goto out;

			}

			cpage_out = page_address(out_page);

			cpage_out = kmap(out_page);

			pages[nr_pages] = out_page;

			nr_pages++;

			workspace->strm.avail_out = PAGE_SIZE;
@@ -258,8 +264,13 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 
	*total_in = workspace->strm.total_in;

out:

	*out_pages = nr_pages;

	if (in_page)

	if (out_page)

		kunmap(out_page);



	if (in_page) {

		kunmap(in_page);

		put_page(in_page);

	}

	return ret;

}
@@ -276,7 +287,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 
	unsigned long buf_start;

	struct page **pages_in = cb->compressed_pages;



	data_in = page_address(pages_in[page_in_index]);

	data_in = kmap(pages_in[page_in_index]);

	workspace->strm.next_in = data_in;

	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);

	workspace->strm.total_in = 0;
@@ -298,6 +309,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 


	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {

		pr_warn("BTRFS: inflateInit failed\n");

		kunmap(pages_in[page_in_index]);

		return -EIO;

	}

	while (workspace->strm.total_in < srclen) {
@@ -324,13 +336,13 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 


		if (workspace->strm.avail_in == 0) {

			unsigned long tmp;



			kunmap(pages_in[page_in_index]);

			page_in_index++;

			if (page_in_index >= total_pages_in) {

				data_in = NULL;

				break;

			}

			data_in = page_address(pages_in[page_in_index]);

			data_in = kmap(pages_in[page_in_index]);

			workspace->strm.next_in = data_in;

			tmp = srclen - workspace->strm.total_in;

			workspace->strm.avail_in = min(tmp, PAGE_SIZE);
@@ -342,6 +354,8 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 
		ret = 0;

done:

	zlib_inflateEnd(&workspace->strm);

	if (data_in)

		kunmap(pages_in[page_in_index]);

	if (!ret)

		zero_fill_bio(cb->orig_bio);

	return ret;