f2fs: compress: add compress_inode to cache compressed blocks

Support to use address space of inner inode to cache compressed block,
in order to improve cache hit ratio of random read.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 166 insertions, 2 deletions

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 1c3e98085591..455561826c7d 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -12,9 +12,11 @@
 #include <linux/lzo.h>
 #include <linux/lz4.h>
 #include <linux/zstd.h>
+#include <linux/pagevec.h>
 
 #include "f2fs.h"
 #include "node.h"
+#include "segment.h"
 #include <trace/events/f2fs.h>
 
 static struct kmem_cache *cic_entry_slab;
@@ -736,7 +738,7 @@ out:
 	return ret;
 }
 
-static void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
+void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
 	struct f2fs_inode_info *fi = F2FS_I(dic->inode);
@@ -835,7 +837,8 @@ out_end_io:
  * page being waited on in the cluster, and if so, it decompresses the cluster
  * (or in the case of a failure, cleans up without actually decompressing).
  */
-void f2fs_end_read_compressed_page(struct page *page, bool failed)
+void f2fs_end_read_compressed_page(struct page *page, bool failed,
+						block_t blkaddr)
 {
 	struct decompress_io_ctx *dic =
 			(struct decompress_io_ctx *)page_private(page);
@@ -845,6 +848,9 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed)
 
 	if (failed)
 		WRITE_ONCE(dic->failed, true);
+	else if (blkaddr)
+		f2fs_cache_compressed_page(sbi, page,
+					dic->inode->i_ino, blkaddr);
 
 	if (atomic_dec_and_test(&dic->remaining_pages))
 		f2fs_decompress_cluster(dic);
@@ -1660,6 +1666,164 @@ void f2fs_put_page_dic(struct page *page)
 	f2fs_put_dic(dic);
 }
 
+const struct address_space_operations f2fs_compress_aops = {
+	.releasepage = f2fs_release_page,
+	.invalidatepage = f2fs_invalidate_page,
+};
+
+struct address_space *COMPRESS_MAPPING(struct f2fs_sb_info *sbi)
+{
+	return sbi->compress_inode->i_mapping;
+}
+
+void f2fs_invalidate_compress_page(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+	if (!sbi->compress_inode)
+		return;
+	invalidate_mapping_pages(COMPRESS_MAPPING(sbi), blkaddr, blkaddr);
+}
+
+void f2fs_cache_compressed_page(struct f2fs_sb_info *sbi, struct page *page,
+						nid_t ino, block_t blkaddr)
+{
+	struct page *cpage;
+	int ret;
+
+	if (!test_opt(sbi, COMPRESS_CACHE))
+		return;
+
+	if (!f2fs_is_valid_blkaddr(sbi, blkaddr, DATA_GENERIC_ENHANCE_READ))
+		return;
+
+	if (!f2fs_available_free_memory(sbi, COMPRESS_PAGE))
+		return;
+
+	cpage = find_get_page(COMPRESS_MAPPING(sbi), blkaddr);
+	if (cpage) {
+		f2fs_put_page(cpage, 0);
+		return;
+	}
+
+	cpage = alloc_page(__GFP_NOWARN | __GFP_IO);
+	if (!cpage)
+		return;
+
+	ret = add_to_page_cache_lru(cpage, COMPRESS_MAPPING(sbi),
+						blkaddr, GFP_NOFS);
+	if (ret) {
+		f2fs_put_page(cpage, 0);
+		return;
+	}
+
+	set_page_private_data(cpage, ino);
+
+	if (!f2fs_is_valid_blkaddr(sbi, blkaddr, DATA_GENERIC_ENHANCE_READ))
+		goto out;
+
+	memcpy(page_address(cpage), page_address(page), PAGE_SIZE);
+	SetPageUptodate(cpage);
+out:
+	f2fs_put_page(cpage, 1);
+}
+
+bool f2fs_load_compressed_page(struct f2fs_sb_info *sbi, struct page *page,
+								block_t blkaddr)
+{
+	struct page *cpage;
+	bool hitted = false;
+
+	if (!test_opt(sbi, COMPRESS_CACHE))
+		return false;
+
+	cpage = f2fs_pagecache_get_page(COMPRESS_MAPPING(sbi),
+				blkaddr, FGP_LOCK | FGP_NOWAIT, GFP_NOFS);
+	if (cpage) {
+		if (PageUptodate(cpage)) {
+			atomic_inc(&sbi->compress_page_hit);
+			memcpy(page_address(page),
+				page_address(cpage), PAGE_SIZE);
+			hitted = true;
+		}
+		f2fs_put_page(cpage, 1);
+	}
+
+	return hitted;
+}
+
+void f2fs_invalidate_compress_pages(struct f2fs_sb_info *sbi, nid_t ino)
+{
+	struct address_space *mapping = sbi->compress_inode->i_mapping;
+	struct pagevec pvec;
+	pgoff_t index = 0;
+	pgoff_t end = MAX_BLKADDR(sbi);
+
+	if (!mapping->nrpages)
+		return;
+
+	pagevec_init(&pvec);
+
+	do {
+		unsigned int nr_pages;
+		int i;
+
+		nr_pages = pagevec_lookup_range(&pvec, mapping,
+						&index, end - 1);
+		if (!nr_pages)
+			break;
+
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			if (page->index > end)
+				break;
+
+			lock_page(page);
+			if (page->mapping != mapping) {
+				unlock_page(page);
+				continue;
+			}
+
+			if (ino != get_page_private_data(page)) {
+				unlock_page(page);
+				continue;
+			}
+
+			generic_error_remove_page(mapping, page);
+			unlock_page(page);
+		}
+		pagevec_release(&pvec);
+		cond_resched();
+	} while (index < end);
+}
+
+int f2fs_init_compress_inode(struct f2fs_sb_info *sbi)
+{
+	struct inode *inode;
+
+	if (!test_opt(sbi, COMPRESS_CACHE))
+		return 0;
+
+	inode = f2fs_iget(sbi->sb, F2FS_COMPRESS_INO(sbi));
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+	sbi->compress_inode = inode;
+
+	sbi->compress_percent = COMPRESS_PERCENT;
+	sbi->compress_watermark = COMPRESS_WATERMARK;
+
+	atomic_set(&sbi->compress_page_hit, 0);
+
+	return 0;
+}
+
+void f2fs_destroy_compress_inode(struct f2fs_sb_info *sbi)
+{
+	if (!sbi->compress_inode)
+		return;
+	iput(sbi->compress_inode);
+	sbi->compress_inode = NULL;
+}
+
 int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi)
 {
 	dev_t dev = sbi->sb->s_bdev->bd_dev;