[PATCH] f2fs: allow writeback on error status filesystem

[Chao Yu]

    71.07%     0.01%  kworker/u256:1+  [kernel.kallsyms]  [k] wb_writeback
            |
             --71.06%--wb_writeback
                       |
                       |--68.96%--__writeback_inodes_wb
                       |          |
                       |           --68.95%--writeback_sb_inodes
                       |                     |
                       |                     |--65.08%--__writeback_single_inode
                       |                     |          |
                       |                     |           --64.35%--do_writepages
                       |                     |                     |
                       |                     |                     |--59.83%--f2fs_write_node_pages
                       |                     |                     |          |
                       |                     |                     |           --59.74%--f2fs_sync_node_pages
                       |                     |                     |                     |
                       |                     |                     |                     |--27.91%--pagevec_lookup_range_tag
                       |                     |                     |                     |          |
                       |                     |                     |                     |           --27.90%--find_get_pages_range_tag

If filesystem was injected w/ checkpoint errror, before umount, kworker
will always hold one core in order to writeback a large number of node
pages, that looks not reasonable, to avoid that, we can allow data/node
write in such case, since we can force all data/node writes with OPU mode,
and clear recovery flag on node, and checkpoint is not allowed as well,
so we don't need to worry about writeback's effect on data/node in
previous checkpoint, then with this way, it can decrease memory footprint
cost by node/data pages and avoid looping into data/node writeback
process.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
 fs/f2fs/data.c | 19 ++++++++++++-------
 fs/f2fs/node.c |  7 +++++--
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 9d40db50cd65..2b3c846181bb 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2519,6 +2519,8 @@ bool f2fs_should_update_outplace(struct inode *inode, struct f2fs_io_info *fio)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 
+	if (unlikely(f2fs_cp_error(sbi)))
+		return true;
 	if (f2fs_lfs_mode(sbi))
 		return true;
 	if (S_ISDIR(inode->i_mode))
@@ -2702,13 +2704,16 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
 	/* we should bypass data pages to proceed the kworkder jobs */
 	if (unlikely(f2fs_cp_error(sbi))) {
 		mapping_set_error(page->mapping, -EIO);
-		/*
-		 * don't drop any dirty dentry pages for keeping lastest
-		 * directory structure.
-		 */
-		if (S_ISDIR(inode->i_mode))
-			goto redirty_out;
-		goto out;
+
+		if (has_not_enough_free_secs(sbi, 0, 0)) {
+			/*
+			 * don't drop any dirty dentry pages for keeping lastest
+			 * directory structure.
+			 */
+			if (S_ISDIR(inode->i_mode))
+				goto redirty_out;
+			goto out;
+		}
 	}
 
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 03e24df1c84f..372c04efad38 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1527,7 +1527,10 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
 			unlock_page(page);
 			return 0;
 		}
-		goto redirty_out;
+		if (has_not_enough_free_secs(sbi, 0, 0))
+			goto redirty_out;
+		set_fsync_mark(page, 0);
+		set_dentry_mark(page, 0);
 	}
 
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
@@ -1568,7 +1571,7 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
 		goto redirty_out;
 	}
 
-	if (atomic && !test_opt(sbi, NOBARRIER))
+	if (atomic && !test_opt(sbi, NOBARRIER) && !f2fs_cp_error(sbi))
 		fio.op_flags |= REQ_PREFLUSH | REQ_FUA;
 
 	/* should add to global list before clearing PAGECACHE status */
-- 
2.18.0.rc1