f2fs: compress: fix overwrite may reduce compress ratio unproperly

when overwrite only first block of cluster, since cluster is not full, it
will call f2fs_write_raw_pages when f2fs_write_multi_pages, and cause the
whole cluster become uncompressed eventhough data can be compressed.
this may will make random write bench score reduce a lot.

root# dd if=/dev/zero of=./fio-test bs=1M count=1

root# sync

root# echo 3 > /proc/sys/vm/drop_caches

root# f2fs_io get_cblocks ./fio-test

root# dd if=/dev/zero of=./fio-test bs=4K count=1 oflag=direct conv=notrunc

w/o patch:
root# f2fs_io get_cblocks ./fio-test
189

w/ patch:
root# f2fs_io get_cblocks ./fio-test
192

Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 9b663ea..7588e4e 100644 (file)
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -881,6 +881,25 @@ bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index)
        return is_page_in_cluster(cc, index);
 }
 
+bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec *pvec,
+                               int index, int nr_pages)
+{
+       unsigned long pgidx;
+       int i;
+
+       if (nr_pages - index < cc->cluster_size)
+               return false;
+
+       pgidx = pvec->pages[index]->index;
+
+       for (i = 1; i < cc->cluster_size; i++) {
+               if (pvec->pages[index + i]->index != pgidx + i)
+                       return false;
+       }
+
+       return true;
+}
+
 static bool cluster_has_invalid_data(struct compress_ctx *cc)
 {
        loff_t i_size = i_size_read(cc->inode);

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 84d5d6c..74e1a35 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3040,6 +3040,10 @@ readd:
                        need_readd = false;
 #ifdef CONFIG_F2FS_FS_COMPRESSION
                        if (f2fs_compressed_file(inode)) {
+                               void *fsdata = NULL;
+                               struct page *pagep;
+                               int ret2;
+
                                ret = f2fs_init_compress_ctx(&cc);
                                if (ret) {
                                        done = 1;
@@ -3058,27 +3062,23 @@ readd:
                                if (unlikely(f2fs_cp_error(sbi)))
                                        goto lock_page;
 
-                               if (f2fs_cluster_is_empty(&cc)) {
-                                       void *fsdata = NULL;
-                                       struct page *pagep;
-                                       int ret2;
+                               if (!f2fs_cluster_is_empty(&cc))
+                                       goto lock_page;
 
-                                       ret2 = f2fs_prepare_compress_overwrite(
+                               ret2 = f2fs_prepare_compress_overwrite(
                                                        inode, &pagep,
                                                        page->index, &fsdata);
-                                       if (ret2 < 0) {
-                                               ret = ret2;
-                                               done = 1;
-                                               break;
-                                       } else if (ret2 &&
-                                               !f2fs_compress_write_end(inode,
-                                                               fsdata, page->index,
-                                                               1)) {
-                                               retry = 1;
-                                               break;
-                                       }
-                               } else {
-                                       goto lock_page;
+                               if (ret2 < 0) {
+                                       ret = ret2;
+                                       done = 1;
+                                       break;
+                               } else if (ret2 &&
+                                       (!f2fs_compress_write_end(inode,
+                                               fsdata, page->index, 1) ||
+                                        !f2fs_all_cluster_page_loaded(&cc,
+                                               &pvec, i, nr_pages))) {
+                                       retry = 1;
+                                       break;
                                }
                        }
 #endif

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index b8e8f8c..5ba2d53 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4052,6 +4052,8 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
                                                        block_t blkaddr);
 bool f2fs_cluster_is_empty(struct compress_ctx *cc);
 bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
+bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec *pvec,
+                               int index, int nr_pages);
 bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
 void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page);
 int f2fs_write_multi_pages(struct compress_ctx *cc,