f2fs: adjust readahead block number during recovery

In a fragmented image, entries in dnode block list may locate in
incontiguous physical block address space, however, in recovery flow,
we will always readahead BIO_MAX_VECS size blocks, so in such case,
current readahead policy is low efficient, let's adjust readahead
window size dynamically based on consecutiveness of dnode blocks.

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

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index deeda95..a13b6b4 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -282,18 +282,22 @@ out:
        return blkno - start;
 }
 
-void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index)
+void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index,
+                                                       unsigned int ra_blocks)
 {
        struct page *page;
        bool readahead = false;
 
+       if (ra_blocks == RECOVERY_MIN_RA_BLOCKS)
+               return;
+
        page = find_get_page(META_MAPPING(sbi), index);
        if (!page || !PageUptodate(page))
                readahead = true;
        f2fs_put_page(page, 0);
 
        if (readahead)
-               f2fs_ra_meta_pages(sbi, index, BIO_MAX_VECS, META_POR, true);
+               f2fs_ra_meta_pages(sbi, index, ra_blocks, META_POR, true);
 }
 
 static int __f2fs_write_meta_page(struct page *page,

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 63c9041..51c1392 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -590,6 +590,9 @@ enum {
 /* number of extent info in extent cache we try to shrink */
 #define EXTENT_CACHE_SHRINK_NUMBER     128
 
+#define RECOVERY_MAX_RA_BLOCKS         BIO_MAX_VECS
+#define RECOVERY_MIN_RA_BLOCKS         1
+
 struct rb_entry {
        struct rb_node rb_node;         /* rb node located in rb-tree */
        union {
@@ -3651,7 +3654,8 @@ bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi,
                                        block_t blkaddr, int type);
 int f2fs_ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,
                        int type, bool sync);
-void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index);
+void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index,
+                                                       unsigned int ra_blocks);
 long f2fs_sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
                        long nr_to_write, enum iostat_type io_type);
 void f2fs_add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type);

diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 10d152c..2af503f 100644 (file)
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -343,6 +343,19 @@ static int recover_inode(struct inode *inode, struct page *page)
        return 0;
 }
 
+static unsigned int adjust_por_ra_blocks(struct f2fs_sb_info *sbi,
+                               unsigned int ra_blocks, unsigned int blkaddr,
+                               unsigned int next_blkaddr)
+{
+       if (blkaddr + 1 == next_blkaddr)
+               ra_blocks = min_t(unsigned int, RECOVERY_MAX_RA_BLOCKS,
+                                                       ra_blocks * 2);
+       else if (next_blkaddr % sbi->blocks_per_seg)
+               ra_blocks = max_t(unsigned int, RECOVERY_MIN_RA_BLOCKS,
+                                                       ra_blocks / 2);
+       return ra_blocks;
+}
+
 static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
                                bool check_only)
 {
@@ -350,6 +363,7 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
        struct page *page = NULL;
        block_t blkaddr;
        unsigned int loop_cnt = 0;
+       unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS;
        unsigned int free_blocks = MAIN_SEGS(sbi) * sbi->blocks_per_seg -
                                                valid_user_blocks(sbi);
        int err = 0;
@@ -424,11 +438,14 @@ next:
                        break;
                }
 
+               ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr,
+                                               next_blkaddr_of_node(page));
+
                /* check next segment */
                blkaddr = next_blkaddr_of_node(page);
                f2fs_put_page(page, 1);
 
-               f2fs_ra_meta_pages_cond(sbi, blkaddr);
+               f2fs_ra_meta_pages_cond(sbi, blkaddr, ra_blocks);
        }
        return err;
 }
@@ -704,6 +721,7 @@ static int recover_data(struct f2fs_sb_info *sbi, struct list_head *inode_list,
        struct page *page = NULL;
        int err = 0;
        block_t blkaddr;
+       unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS;
 
        /* get node pages in the current segment */
        curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);
@@ -715,8 +733,6 @@ static int recover_data(struct f2fs_sb_info *sbi, struct list_head *inode_list,
                if (!f2fs_is_valid_blkaddr(sbi, blkaddr, META_POR))
                        break;
 
-               f2fs_ra_meta_pages_cond(sbi, blkaddr);
-
                page = f2fs_get_tmp_page(sbi, blkaddr);
                if (IS_ERR(page)) {
                        err = PTR_ERR(page);
@@ -759,9 +775,14 @@ static int recover_data(struct f2fs_sb_info *sbi, struct list_head *inode_list,
                if (entry->blkaddr == blkaddr)
                        list_move_tail(&entry->list, tmp_inode_list);
 next:
+               ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr,
+                                               next_blkaddr_of_node(page));
+
                /* check next segment */
                blkaddr = next_blkaddr_of_node(page);
                f2fs_put_page(page, 1);
+
+               f2fs_ra_meta_pages_cond(sbi, blkaddr, ra_blocks);
        }
        if (!err)
                f2fs_allocate_new_segments(sbi);