Commit 7bf9bfa9 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: prepare compression paths for large data folios 



All compression algorithms inside btrfs are not supporting large folios
due to the following points:

- btrfs_calc_input_length() is assuming page sized folio

- kmap_local_folio() usages are using offset_in_page()

Prepare them to support large data folios by:

- Add a folio parameter to btrfs_calc_input_length()
  And use that folio parameter to calculate the correct length.

  Since we're here, also add extra ASSERT()s to make sure the parameter
  @cur is inside the folio range.

  This affects only zlib and zstd. Lzo compresses at most one block at a
  time, thus not affected.

- Use offset_in_folio() to calculate the kmap_local_folio() offset
  This affects all 3 algorithms.

Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 9a36bad6

fs/btrfs/compression.h

+8 −3
Original line number Diff line number Diff line
@@ -11,7 +11,9 @@ 
#include <linux/list.h>

#include <linux/workqueue.h>

#include <linux/wait.h>

#include <linux/pagemap.h>

#include "bio.h"

#include "messages.h"



struct address_space;

struct page;
@@ -73,11 +75,14 @@ struct compressed_bio { 
};



/* @range_end must be exclusive. */

static inline u32 btrfs_calc_input_length(u64 range_end, u64 cur)

static inline u32 btrfs_calc_input_length(struct folio *folio, u64 range_end, u64 cur)

{

	u64 page_end = round_down(cur, PAGE_SIZE) + PAGE_SIZE;

	const u64 folio_end = folio_pos(folio) + folio_size(folio);



	return min(range_end, page_end) - cur;

	/* @cur must be inside the folio. */

	ASSERT(folio_pos(folio) <= cur);

	ASSERT(cur < folio_end);

	return min(range_end, folio_end) - cur;

}



int __init btrfs_init_compress(void);

fs/btrfs/lzo.c

+2 −3
Original line number Diff line number Diff line
@@ -252,9 +252,8 @@ int lzo_compress_folios(struct list_head *ws, struct address_space *mapping, 
		/* Compress at most one sector of data each time */

		in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off);

		ASSERT(in_len);

		data_in = kmap_local_folio(folio_in, 0);

		ret = lzo1x_1_compress(data_in +

				       offset_in_page(cur_in), in_len,

		data_in = kmap_local_folio(folio_in, offset_in_folio(folio_in, cur_in));

		ret = lzo1x_1_compress(data_in, in_len,

				       workspace->cbuf, &out_len,

				       workspace->mem);

		kunmap_local(data_in);

fs/btrfs/zlib.c

+3 −4
Original line number Diff line number Diff line
@@ -203,7 +203,6 @@ int zlib_compress_folios(struct list_head *ws, struct address_space *mapping, 
				workspace->strm.next_in = workspace->buf;

				workspace->strm.avail_in = copy_length;

			} else {

				unsigned int pg_off;

				unsigned int cur_len;



				if (data_in) {
@@ -215,9 +214,9 @@ int zlib_compress_folios(struct list_head *ws, struct address_space *mapping, 
						start, &in_folio);

				if (ret < 0)

					goto out;

				pg_off = offset_in_page(start);

				cur_len = btrfs_calc_input_length(orig_end, start);

				data_in = kmap_local_folio(in_folio, pg_off);

				cur_len = btrfs_calc_input_length(in_folio, orig_end, start);

				data_in = kmap_local_folio(in_folio,

							   offset_in_folio(in_folio, start));

				start += cur_len;

				workspace->strm.next_in = data_in;

				workspace->strm.avail_in = cur_len;

fs/btrfs/zstd.c

+4 −4
Original line number Diff line number Diff line
@@ -426,8 +426,8 @@ int zstd_compress_folios(struct list_head *ws, struct address_space *mapping, 
	ret = btrfs_compress_filemap_get_folio(mapping, start, &in_folio);

	if (ret < 0)

		goto out;

	cur_len = btrfs_calc_input_length(orig_end, start);

	workspace->in_buf.src = kmap_local_folio(in_folio, offset_in_page(start));

	cur_len = btrfs_calc_input_length(in_folio, orig_end, start);

	workspace->in_buf.src = kmap_local_folio(in_folio, offset_in_folio(in_folio, start));

	workspace->in_buf.pos = 0;

	workspace->in_buf.size = cur_len;
@@ -511,9 +511,9 @@ int zstd_compress_folios(struct list_head *ws, struct address_space *mapping, 
			ret = btrfs_compress_filemap_get_folio(mapping, start, &in_folio);

			if (ret < 0)

				goto out;

			cur_len = btrfs_calc_input_length(orig_end, start);

			cur_len = btrfs_calc_input_length(in_folio, orig_end, start);

			workspace->in_buf.src = kmap_local_folio(in_folio,

							 offset_in_page(start));

							 offset_in_folio(in_folio, start));

			workspace->in_buf.pos = 0;

			workspace->in_buf.size = cur_len;

		}