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>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 56bbf592e487577b4d21614d7f56c1dbfc45e2c3..5b876f6d3f6b1d81a661f00a3d7c40cb99a83597 100644 (file)
--- 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