f2fs: avoid cpu lockup

Before retrying to flush data or dentry pages, we need to release cpu in order
to prevent watchdog.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 56bbf592e487..5b876f6d3f6b 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -879,6 +879,7 @@ int sync_dirty_inodes(struct f2fs_sb_info *sbi, enum inode_type type)
         struct inode *inode;
         struct f2fs_inode_info *fi;
         bool is_dir = (type == DIR_INODE);
+        unsigned long ino = 0;
 
         trace_f2fs_sync_dirty_inodes_enter(sbi->sb, is_dir,
                                 get_pages(sbi, is_dir ?
@@ -901,8 +902,17 @@ retry:
         inode = igrab(&fi->vfs_inode);
         spin_unlock(&sbi->inode_lock[type]);
         if (inode) {
+                unsigned long cur_ino = inode->i_ino;
+
                 filemap_fdatawrite(inode->i_mapping);
                 iput(inode);
+                /* We need to give cpu to another writers. */
+                if (ino == cur_ino) {
+                        congestion_wait(BLK_RW_ASYNC, HZ/50);
+                        cond_resched();
+                } else {
+                        ino = cur_ino;
+                }
         } else {
                 /*
                  * We should submit bio, since it exists several