ext4: async direct IO for holes and fallocate support

For async direct IO that covers holes or fallocate, the end_io
callback function now queued the convertion work on workqueue but
don't flush the work rightaway as it might take too long to afford.

But when fsync is called after all the data is completed, user expects
the metadata also being updated before fsync returns.

Thus we need to flush the conversion work when fsync() is called.
This patch keep track of a listed of completed async direct io that
has a work queued on workqueue.  When fsync() is called, it will go
through the list and do the conversion.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ccb4dbf..b491576 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -127,10 +127,11 @@ struct mpage_da_data {
 	int pages_written;
 	int retval;
 };
-
+#define	DIO_AIO_UNWRITTEN	0x1
 typedef struct ext4_io_end {
+	struct list_head	list;		/* per-file finished AIO list */
 	struct inode		*inode;		/* file being written to */
-	unsigned int		flag;		/* sync IO or AIO */
+	unsigned int		flag;		/* unwritten or not */
 	int			error;		/* I/O error code */
 	ext4_lblk_t		offset;		/* offset in the file */
 	size_t			size;		/* size of the extent */
@@ -690,6 +691,11 @@ struct ext4_inode_info {
 	__u16 i_extra_isize;
 
 	spinlock_t i_block_reservation_lock;
+
+	/* completed async DIOs that might need unwritten extents handling */
+	struct list_head i_aio_dio_complete_list;
+	/* current io_end structure for async DIO write*/
+	ext4_io_end_t *cur_aio_dio;
 };
 
 /*
@@ -1419,7 +1425,7 @@ extern int ext4_block_truncate_page(handle_t *handle,
 		struct address_space *mapping, loff_t from);
 extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
 extern qsize_t ext4_get_reserved_space(struct inode *inode);
-
+extern int flush_aio_dio_completed_IO(struct inode *inode);
 /* ioctl.c */
 extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
 extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);