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

commit 2743f865543c0c4a5e12fc13edb2bf89a6e9687c upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index a9c04950affdafecbbf250da66b2fa1ad3948c85..5696bde95702176075b2ddb23df9eec7d8e62f8e 100644 (file)
--- 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);
        }