[PATCH v2 07/12] ext4: add fields that are needed to track changed files

[Harshad Shirwadkar <harshadshirwadkar@gmail.com>]

Ext4's fast commit feature tracks changed files and maintains them in
a queue. We also remember for each file the logical block range that
needs to be committed. This patch adds these fields to ext4_inode_info
and ext4_sb_info and also adds initialization calls.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>

---

Changelog:

V2: Converted s_fc_lock from mutex to spinlock to improve parallelism
    performance.
---
 fs/ext4/ext4.h      | 34 ++++++++++++++++++++++++++++++++++
 fs/ext4/ext4_jbd2.c | 13 +++++++++++++
 fs/ext4/ext4_jbd2.h |  2 ++
 fs/ext4/inode.c     |  1 +
 fs/ext4/super.c     |  7 +++++++
 5 files changed, 57 insertions(+)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index becbda38b7db..0d15d4539dda 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -921,6 +921,27 @@ enum {
 	I_DATA_SEM_QUOTA,
 };
 
+/*
+ * Ext4 fast commit inode specific information
+ */
+struct ext4_fast_commit_inode_info {
+	/* TID / SUB-TID when old_i_size and i_size were recorded */
+	tid_t fc_tid;
+	tid_t fc_subtid;
+
+	/*
+	 * Start of logical block range that needs to be committed in this fast
+	 * commit
+	 */
+	loff_t fc_lblk_start;
+
+	/*
+	 * End of logical block range that needs to be committed in this fast
+	 * commit
+	 */
+	loff_t fc_lblk_end;
+};
+
 
 /*
  * fourth extended file system inode data in memory
@@ -955,6 +976,9 @@ struct ext4_inode_info {
 
 	struct list_head i_orphan;	/* unlinked but open inodes */
 
+	struct list_head i_fc_list;	/* inodes that need fast commit */
+	struct ext4_fast_commit_inode_info i_fc;
+
 	/*
 	 * i_disksize keeps track of what the inode size is ON DISK, not
 	 * in memory.  During truncate, i_size is set to the new size by
@@ -1529,6 +1553,16 @@ struct ext4_sb_info {
 	/* Barrier between changing inodes' journal flags and writepages ops. */
 	struct percpu_rw_semaphore s_journal_flag_rwsem;
 	struct dax_device *s_daxdev;
+
+	/* Ext4 fast commit stuff */
+	bool fc_replay;			/* Fast commit replay in progress */
+	struct list_head s_fc_q;	/* Inodes that need fast commit. */
+	__u32 s_fc_q_cnt;		/* Number of inodes in the fc queue */
+	bool s_fc_eligible;		/*
+					 * Are changes after the last commit
+					 * eligible for fast commit?
+					 */
+	spinlock_t s_fc_lock;
 };
 
 static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index 7c70b08d104c..75b6db808837 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -330,3 +330,16 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line,
 		mark_buffer_dirty(bh);
 	return err;
 }
+
+void ext4_init_inode_fc_info(struct inode *inode)
+{
+	handle_t *handle = ext4_journal_current_handle();
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	memset(&ei->i_fc, 0, sizeof(ei->i_fc));
+	if (ext4_handle_valid(handle)) {
+		ei->i_fc.fc_tid = handle->h_transaction->t_tid;
+		ei->i_fc.fc_subtid = handle->h_transaction->t_journal->j_subtid;
+	}
+	INIT_LIST_HEAD(&ei->i_fc_list);
+}
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index ef8fcf7d0d3b..2305c1acd415 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -459,4 +459,6 @@ static inline int ext4_should_dioread_nolock(struct inode *inode)
 	return 1;
 }
 
+void ext4_init_inode_fc_info(struct inode *inode);
+
 #endif	/* _EXT4_JBD2_H */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 420fe3deed39..f230a888eddd 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4996,6 +4996,7 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
 	for (block = 0; block < EXT4_N_BLOCKS; block++)
 		ei->i_data[block] = raw_inode->i_block[block];
 	INIT_LIST_HEAD(&ei->i_orphan);
+	ext4_init_inode_fc_info(&ei->vfs_inode);
 
 	/*
 	 * Set transaction id's of transactions that have to be committed
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6bab59ae81f7..0b833e9b61c1 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1100,6 +1100,7 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
 	ei->i_datasync_tid = 0;
 	atomic_set(&ei->i_unwritten, 0);
 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
+	ext4_init_inode_fc_info(&ei->vfs_inode);
 	return &ei->vfs_inode;
 }
 
@@ -1139,6 +1140,7 @@ static void init_once(void *foo)
 	init_rwsem(&ei->i_data_sem);
 	init_rwsem(&ei->i_mmap_sem);
 	inode_init_once(&ei->vfs_inode);
+	ext4_init_inode_fc_info(&ei->vfs_inode);
 }
 
 static int __init init_inodecache(void)
@@ -4301,6 +4303,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
 	mutex_init(&sbi->s_orphan_lock);
 
+	INIT_LIST_HEAD(&sbi->s_fc_q);
+	sbi->s_fc_q_cnt = 0;
+	sbi->s_fc_eligible = true;
+	spin_lock_init(&sbi->s_fc_lock);
+
 	sb->s_root = NULL;
 
 	needs_recovery = (es->s_last_orphan != 0 ||
-- 
2.23.0.rc1.153.gdeed80330f-goog