ext4: remove unused member 'i_unwritten' from 'ext4_inode_info'

After commit 378f32b ("ext4: introduce direct I/O write using iomap
infrastructure"), no one cares about the value of i_unwritten, so there
is no need to maintain this variable, remove it, and clean up the
associated logic.

Suggested-by: Zhang Yi <[email protected]>
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Zhang Yi <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>

Author: LiBaokun96

fs/ext4/ext4.h

@@ -1063,7 +1063,6 @@ struct ext4_inode_info {
 
 	/* Number of ongoing updates on this inode */
 	atomic_t  i_fc_updates;
-	atomic_t i_unwritten; /* Nr. of inflight conversions pending */
 
 	/* Fast commit wait queue for this inode */
 	wait_queue_head_t i_fc_wait;
@@ -3792,34 +3791,19 @@ static inline void set_bitmap_uptodate(struct buffer_head *bh)
 	set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
 }
 
-/* For ioend & aio unwritten conversion wait queues */
-#define EXT4_WQ_HASH_SZ		37
-#define ext4_ioend_wq(v)   (&ext4__ioend_wq[((unsigned long)(v)) %\
-					    EXT4_WQ_HASH_SZ])
-extern wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
-
 extern int ext4_resize_begin(struct super_block *sb);
 extern int ext4_resize_end(struct super_block *sb, bool update_backups);
 
-static inline void ext4_set_io_unwritten_flag(struct inode *inode,
-					      struct ext4_io_end *io_end)
+static inline void ext4_set_io_unwritten_flag(struct ext4_io_end *io_end)
 {
-	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
+	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN))
 		io_end->flag |= EXT4_IO_END_UNWRITTEN;
-		atomic_inc(&EXT4_I(inode)->i_unwritten);
-	}
 }
 
 static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
 {
-	struct inode *inode = io_end->inode;
-
-	if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+	if (io_end->flag & EXT4_IO_END_UNWRITTEN)
 		io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
-		/* Wake up anyone waiting on unwritten extent conversion */
-		if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
-			wake_up_all(ext4_ioend_wq(inode));
-	}
 }
 
 extern const struct iomap_ops ext4_iomap_ops;

fs/ext4/inode.c

@@ -2226,7 +2226,7 @@ static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
 			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
 			handle->h_rsv_handle = NULL;
 		}
-		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
+		ext4_set_io_unwritten_flag(mpd->io_submit.io_end);
 	}
 
 	BUG_ON(map->m_len == 0);

fs/ext4/super.c

@@ -1411,7 +1411,6 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
 	spin_lock_init(&ei->i_completed_io_lock);
 	ei->i_sync_tid = 0;
 	ei->i_datasync_tid = 0;
-	atomic_set(&ei->i_unwritten, 0);
 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
 	ext4_fc_init_inode(&ei->vfs_inode);
 	mutex_init(&ei->i_fc_lock);
@@ -7391,22 +7390,16 @@ static struct file_system_type ext4_fs_type = {
 };
 MODULE_ALIAS_FS("ext4");
 
-/* Shared across all ext4 file systems */
-wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
-
 static int __init ext4_init_fs(void)
 {
-	int i, err;
+	int err;
 
 	ratelimit_state_init(&ext4_mount_msg_ratelimit, 30 * HZ, 64);
 	ext4_li_info = NULL;
 
 	/* Build-time check for flags consistency */
 	ext4_check_flag_values();
 
-	for (i = 0; i < EXT4_WQ_HASH_SZ; i++)
-		init_waitqueue_head(&ext4__ioend_wq[i]);
-
 	err = ext4_init_es();
 	if (err)
 		return err;