f2fs: guarantee journalled quota data by checkpoint

For journalled quota mode, let checkpoint to flush dquot dirty data
and quota file data to guarntee persistence of all quota sysfile in
last checkpoint, by this way, we can avoid corrupting quota sysfile
when encountering SPO.

The implementation is as below:

1. add a global state SBI_QUOTA_NEED_FLUSH to indicate that there is
cached dquot metadata changes in quota subsystem, and later checkpoint
should:
 a) flush dquot metadata into quota file.
 b) flush quota file to storage to keep file usage be consistent.

2. add a global state SBI_QUOTA_NEED_REPAIR to indicate that quota
operation failed due to -EIO or -ENOSPC, so later,
 a) checkpoint will skip syncing dquot metadata.
 b) CP_QUOTA_NEED_FSCK_FLAG will be set in last cp pack to give a
    hint for fsck repairing.

3. add a global state SBI_QUOTA_SKIP_FLUSH, in checkpoint, if quota
data updating is very heavy, it may cause hungtask in block_operation().
To avoid this, if our retry time exceed threshold, let's just skip
flushing and retry in next checkpoint().

Signed-off-by: Weichao Guo <guoweichao@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: avoid warnings and set fsck flag]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 58 insertions, 4 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index eb6ac79640f8..9c28ea439e0b 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1079,6 +1079,21 @@ static void __prepare_cp_block(struct f2fs_sb_info *sbi)
 	ckpt->next_free_nid = cpu_to_le32(last_nid);
 }
 
+static bool __need_flush_quota(struct f2fs_sb_info *sbi)
+{
+	if (!is_journalled_quota(sbi))
+		return false;
+	if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
+		return false;
+	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
+		return false;
+	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_FLUSH))
+		return true;
+	if (get_pages(sbi, F2FS_DIRTY_QDATA))
+		return true;
+	return false;
+}
+
 /*
  * Freeze all the FS-operations for checkpoint.
  */
@@ -1090,12 +1105,36 @@ static int block_operations(struct f2fs_sb_info *sbi)
 		.for_reclaim = 0,
 	};
 	struct blk_plug plug;
-	int err = 0;
+	int err = 0, cnt = 0;
 
 	blk_start_plug(&plug);
 
-retry_flush_dents:
+retry_flush_quotas:
+	if (__need_flush_quota(sbi)) {
+		int locked;
+
+		if (++cnt > DEFAULT_RETRY_QUOTA_FLUSH_COUNT) {
+			set_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH);
+			f2fs_lock_all(sbi);
+			goto retry_flush_dents;
+		}
+		clear_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);
+
+		/* only failed during mount/umount/freeze/quotactl */
+		locked = down_read_trylock(&sbi->sb->s_umount);
+		f2fs_quota_sync(sbi->sb, -1);
+		if (locked)
+			up_read(&sbi->sb->s_umount);
+	}
+
 	f2fs_lock_all(sbi);
+	if (__need_flush_quota(sbi)) {
+		f2fs_unlock_all(sbi);
+		cond_resched();
+		goto retry_flush_quotas;
+	}
+
+retry_flush_dents:
 	/* write all the dirty dentry pages */
 	if (get_pages(sbi, F2FS_DIRTY_DENTS)) {
 		f2fs_unlock_all(sbi);
@@ -1103,7 +1142,7 @@ retry_flush_dents:
 		if (err)
 			goto out;
 		cond_resched();
-		goto retry_flush_dents;
+		goto retry_flush_quotas;
 	}
 
 	/*
@@ -1112,6 +1151,12 @@ retry_flush_dents:
 	 */
 	down_write(&sbi->node_change);
 
+	if (__need_flush_quota(sbi)) {
+		up_write(&sbi->node_change);
+		f2fs_unlock_all(sbi);
+		goto retry_flush_quotas;
+	}
+
 	if (get_pages(sbi, F2FS_DIRTY_IMETA)) {
 		up_write(&sbi->node_change);
 		f2fs_unlock_all(sbi);
@@ -1119,7 +1164,7 @@ retry_flush_dents:
 		if (err)
 			goto out;
 		cond_resched();
-		goto retry_flush_dents;
+		goto retry_flush_quotas;
 	}
 
 retry_flush_nodes:
@@ -1215,6 +1260,14 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	else
 		__clear_ckpt_flags(ckpt, CP_DISABLED_FLAG);
 
+	if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
+		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
+	else
+		__clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
+
+	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
+		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
+
 	/* set this flag to activate crc|cp_ver for recovery */
 	__set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG);
 	__clear_ckpt_flags(ckpt, CP_NOCRC_RECOVERY_FLAG);
@@ -1422,6 +1475,7 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
 	clear_sbi_flag(sbi, SBI_IS_DIRTY);
 	clear_sbi_flag(sbi, SBI_NEED_CP);
+	clear_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH);
 	sbi->unusable_block_count = 0;
 	__set_cp_next_pack(sbi);