[PATCH 2/5] ext4: introudce helper for jounral recover handle

[Ye Bin <yebin@huaweicloud.com>]

From: Ye Bin <yebin10@huawei.com>

Now, ext4 file system only need to handle super block when do
recover journal.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 fs/ext4/ext4_jbd2.c | 65 +++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4_jbd2.h |  2 ++
 fs/ext4/super.c     |  1 +
 3 files changed, 68 insertions(+)

diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index 77f318ec8abb..7c0f2bed0ec4 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -395,3 +395,68 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
 	}
 	return err;
 }
+
+void ext4_replay_end_callback(struct journal_s *journal)
+{
+	kfree(journal->j_replay_private_data);
+	journal->j_replay_private_data = NULL;
+	journal->j_replay_callback = NULL;
+	journal->j_replay_end_callback = NULL;
+}
+
+static int ext4_replay_callback(struct journal_s *journal,
+				struct buffer_head *bh)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct ext4_super_block *nes;
+	unsigned long offset;
+
+	if (likely(sbi->s_sbh != bh))
+		return 0;
+
+	offset = (void*)es - (void*)sbi->s_sbh->b_data;
+	nes = (struct ext4_super_block*)(bh->b_data + offset);
+	/*
+	 * If super block has error flag in journal record, there isn't need to
+	 * cover error information, as in this case is errors=continue mode,
+	 * error handle submit super block through journal.
+	 */
+	if (le16_to_cpu(nes->s_state) & EXT4_ERROR_FS)
+		return 0;
+
+	memcpy(((char *)es) + EXT4_S_ERR_START,
+	       journal->j_replay_private_data, EXT4_S_ERR_LEN);
+	if (sbi->s_mount_state & EXT4_ERROR_FS)
+		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
+
+	return 0;
+}
+
+static int ext4_replay_prepare_callback(struct journal_s *journal)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	char *private;
+	struct ext4_super_block *es = sbi->s_es;
+
+	if (!(sbi->s_mount_state & EXT4_ERROR_FS))
+		return 0;
+
+	private = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
+	if (!private)
+		return -ENOMEM;
+	memcpy(private, ((char *)es) + EXT4_S_ERR_START, EXT4_S_ERR_LEN);
+
+	journal->j_replay_private_data = private;
+	journal->j_replay_callback = ext4_replay_callback;
+	journal->j_replay_end_callback = ext4_replay_end_callback;
+
+	return 0;
+}
+
+void ext4_init_replay(journal_t *journal)
+{
+	journal->j_replay_prepare_callback = ext4_replay_prepare_callback;
+}
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 0c77697d5e90..8dcc7ef5028c 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -513,4 +513,6 @@ static inline int ext4_should_dioread_nolock(struct inode *inode)
 	return 1;
 }
 
+void ext4_init_replay(journal_t *journal);
+
 #endif	/* _EXT4_JBD2_H */
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dc3907dff13a..ea0fea04907c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5677,6 +5677,7 @@ static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
 	journal->j_commit_interval = sbi->s_commit_interval;
 	journal->j_min_batch_time = sbi->s_min_batch_time;
 	journal->j_max_batch_time = sbi->s_max_batch_time;
+	ext4_init_replay(journal);
 	ext4_fc_init(sb, journal);
 
 	write_lock(&journal->j_state_lock);
-- 
2.31.1