f2fs: change atomic and volatile write policies

This patch adds two new ioctls to release inmemory pages grabbed by atomic
writes.
 o f2fs_ioc_abort_volatile_write
  - If transaction was failed, all the grabbed pages and data should be written.
 o f2fs_ioc_release_volatile_write
  - This is to enhance the performance of PERSIST mode in sqlite.

In order to avoid huge memory consumption which causes OOM, this patch changes
volatile writes to use normal dirty pages, instead blocked flushing to the disk
as long as system does not suffer from memory pressure.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index d6f073edd861..cabecee88377 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -61,6 +61,9 @@ bool available_free_memory(struct f2fs_sb_info *sbi, int type)
                         mem_size += (sbi->im[i].ino_num *
                                 sizeof(struct ino_entry)) >> PAGE_CACHE_SHIFT;
                 res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
+        } else {
+                if (sbi->sb->s_bdi->dirty_exceeded)
+                        return false;
         }
         return res;
 }