f2fs: support recording stop_checkpoint reason into super_block

This patch supports to record stop_checkpoint error into
f2fs_super_block.s_stop_reason[].

Signed-off-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/checkpoint.c

···
 static struct kmem_cache *ino_entry_slab;
 struct kmem_cache *f2fs_inode_entry_slab;
 
-void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io)
+void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io,
+						unsigned char reason)
 {
 	f2fs_build_fault_attr(sbi, 0, 0);
 	set_ckpt_flags(sbi, CP_ERROR_FLAG);
-	if (!end_io)
+	if (!end_io) {
 		f2fs_flush_merged_writes(sbi);
+
+		f2fs_handle_stop(sbi, reason);
+	}
 }
 
 /*
···
 		if (PTR_ERR(page) == -EIO &&
 				++count <= DEFAULT_RETRY_IO_COUNT)
 			goto retry;
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_META_PAGE);
 	}
 	return page;
 }

fs/f2fs/data.c

···
 			mempool_free(page, sbi->write_io_dummy);
 
 			if (unlikely(bio->bi_status))
-				f2fs_stop_checkpoint(sbi, true);
+				f2fs_stop_checkpoint(sbi, true,
+						STOP_CP_REASON_WRITE_FAIL);
 			continue;
 		}
 
···
 		if (unlikely(bio->bi_status)) {
 			mapping_set_error(page->mapping, -EIO);
 			if (type == F2FS_WB_CP_DATA)
-				f2fs_stop_checkpoint(sbi, true);
+				f2fs_stop_checkpoint(sbi, true,
+						STOP_CP_REASON_WRITE_FAIL);
 		}
 
 		f2fs_bug_on(sbi, page->mapping == NODE_MAPPING(sbi) &&

fs/f2fs/f2fs.h

···
 int f2fs_quota_sync(struct super_block *sb, int type);
 loff_t max_file_blocks(struct inode *inode);
 void f2fs_quota_off_umount(struct super_block *sb);
+void f2fs_handle_stop(struct f2fs_sb_info *sbi, unsigned char reason);
 int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover);
 int f2fs_sync_fs(struct super_block *sb, int sync);
 int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi);
···
 /*
  * checkpoint.c
  */
-void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io);
+void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io,
+							unsigned char reason);
 void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi);
 struct page *f2fs_grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);
 struct page *f2fs_get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);

fs/f2fs/file.c

···
 		if (ret) {
 			if (ret == -EROFS) {
 				ret = 0;
-				f2fs_stop_checkpoint(sbi, false);
+				f2fs_stop_checkpoint(sbi, false,
+						STOP_CP_REASON_SHUTDOWN);
 				set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
 				trace_f2fs_shutdown(sbi, in, ret);
 			}
···
 		ret = freeze_bdev(sb->s_bdev);
 		if (ret)
 			goto out;
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
 		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
 		thaw_bdev(sb->s_bdev);
 		break;
···
 		ret = f2fs_sync_fs(sb, 1);
 		if (ret)
 			goto out;
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
 		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
 		break;
 	case F2FS_GOING_DOWN_NOSYNC:
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
 		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
 		break;
 	case F2FS_GOING_DOWN_METAFLUSH:
 		f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_META_IO);
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
 		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
 		break;
 	case F2FS_GOING_DOWN_NEED_FSCK:

fs/f2fs/gc.c

···
 
 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
 			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+					STOP_CP_REASON_FAULT_INJECT);
 		}
 
 		if (!sb_start_write_trylock(sbi->sb)) {
···
 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
 				 segno, type, GET_SUM_TYPE((&sum->footer)));
 			set_sbi_flag(sbi, SBI_NEED_FSCK);
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+				STOP_CP_REASON_CORRUPTED_SUMMARY);
 			goto skip;
 		}
 

fs/f2fs/inode.c

···
 			cond_resched();
 			goto retry;
 		} else if (err != -ENOENT) {
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+					STOP_CP_REASON_UPDATE_INODE);
 		}
 		return;
 	}

fs/f2fs/segment.c

···
 {
 	if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
 		f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_FAULT_INJECT);
 	}
 
 	/* balance_fs_bg is able to be pending */
···
 		} while (ret && --count);
 
 		if (ret) {
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+					STOP_CP_REASON_FLUSH_FAIL);
 			break;
 		}
 

fs/f2fs/super.c

···
 	return err;
 }
 
+void f2fs_handle_stop(struct f2fs_sb_info *sbi, unsigned char reason)
+{
+	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
+	int err;
+
+	f2fs_bug_on(sbi, reason >= MAX_STOP_REASON);
+
+	f2fs_down_write(&sbi->sb_lock);
+
+	if (raw_super->s_stop_reason[reason] < ((1 << BITS_PER_BYTE) - 1))
+		raw_super->s_stop_reason[reason]++;
+
+	err = f2fs_commit_super(sbi, false);
+	if (err)
+		f2fs_err(sbi, "f2fs_commit_super fails to record reason:%u err:%d",
+								reason, err);
+
+	f2fs_up_write(&sbi->sb_lock);
+}
+
 static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 {
 	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);

include/linux/f2fs_fs.h

···
 	__le32 total_segments;
 } __packed;
 
+/* reason of stop_checkpoint */
+enum stop_cp_reason {
+	STOP_CP_REASON_SHUTDOWN,
+	STOP_CP_REASON_FAULT_INJECT,
+	STOP_CP_REASON_META_PAGE,
+	STOP_CP_REASON_WRITE_FAIL,
+	STOP_CP_REASON_CORRUPTED_SUMMARY,
+	STOP_CP_REASON_UPDATE_INODE,
+	STOP_CP_REASON_FLUSH_FAIL,
+	STOP_CP_REASON_MAX,
+};
+
+#define	MAX_STOP_REASON			32
+
 struct f2fs_super_block {
 	__le32 magic;			/* Magic Number */
 	__le16 major_ver;		/* Major Version */
···
 	__u8 hot_ext_count;		/* # of hot file extension */
 	__le16  s_encoding;		/* Filename charset encoding */
 	__le16  s_encoding_flags;	/* Filename charset encoding flags */
-	__u8 reserved[306];		/* valid reserved region */
+	__u8 s_stop_reason[MAX_STOP_REASON];	/* stop checkpoint reason */
+	__u8 reserved[274];		/* valid reserved region */
 	__le32 crc;			/* checksum of superblock */
 } __packed;