f2fs: check bdi->dirty_exceeded when trying to skip data writes

If we don't check the current backing device status, balance_dirty_pages can
fall into infinite pausing routine.

This can be occurred when a lot of directories make a small number of dirty
dentry pages including files.

Reported-by: Brian Chadwick <brianchad@westnet.com.au>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 9dfb9a042fd2..4b697ccc9b0c 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -42,6 +42,8 @@ bool available_free_memory(struct f2fs_sb_info *sbi, int type)
                 mem_size = (nm_i->nat_cnt * sizeof(struct nat_entry)) >> 12;
                 res = mem_size < ((val.totalram * nm_i->ram_thresh / 100) >> 2);
         } else if (type == DIRTY_DENTS) {
+                if (sbi->sb->s_bdi->dirty_exceeded)
+                        return false;
                 mem_size = get_pages(sbi, F2FS_DIRTY_DENTS);
                 res = mem_size < ((val.totalram * nm_i->ram_thresh / 100) >> 1);
         }