f2fs: introduce nr_pages_to_write for segment alignment

This patch introduces nr_pages_to_write to align page writes to the segment
or other operational unit size, which can be tuned according to the system
environment.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index aef32f36e2f3..2a00c94726fb 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -187,18 +187,19 @@ static int f2fs_write_meta_pages(struct address_space *mapping,
                                 struct writeback_control *wbc)
 {
         struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
-        int nrpages = nr_pages_to_skip(sbi, META);
-        long written;
+        long diff, written;
 
         /* collect a number of dirty meta pages and write together */
-        if (wbc->for_kupdate || get_pages(sbi, F2FS_DIRTY_META) < nrpages)
+        if (wbc->for_kupdate ||
+                get_pages(sbi, F2FS_DIRTY_META) < nr_pages_to_skip(sbi, META))
                 goto skip_write;
 
         /* if mounting is failed, skip writing node pages */
         mutex_lock(&sbi->cp_mutex);
-        written = sync_meta_pages(sbi, META, nrpages);
+        diff = nr_pages_to_write(sbi, META, wbc);
+        written = sync_meta_pages(sbi, META, wbc->nr_to_write);
         mutex_unlock(&sbi->cp_mutex);
-        wbc->nr_to_write -= written;
+        wbc->nr_to_write = max((long)0, wbc->nr_to_write - written - diff);
         return 0;
 
 skip_write: