COW improvements and always_cow support V3

index 19e921d1586f..f16d42abc500 100644
@@ -3685,17 +3685,6 @@ xfs_trim_extent(
 	}
 }
 
-/* trim extent to within eof */
-void
-xfs_trim_extent_eof(
-	struct xfs_bmbt_irec	*irec,
-	struct xfs_inode	*ip)
-
-{
-	xfs_trim_extent(irec, 0, XFS_B_TO_FSB(ip->i_mount,
-					      i_size_read(VFS_I(ip))));
-}
-
 /*
  * Trim the returned map to the required bounds
  */

index 488dc8860fd7..f9a925caa70e 100644
@@ -181,7 +181,6 @@ static inline bool xfs_bmap_is_real_extent(struct xfs_bmbt_irec *irec)
 
 void	xfs_trim_extent(struct xfs_bmbt_irec *irec, xfs_fileoff_t bno,
 		xfs_filblks_t len);
-void	xfs_trim_extent_eof(struct xfs_bmbt_irec *, struct xfs_inode *);
 int	xfs_bmap_add_attrfork(struct xfs_inode *ip, int size, int rsvd);
 int	xfs_bmap_set_attrforkoff(struct xfs_inode *ip, int size, int *version);
 void	xfs_bmap_local_to_extents_empty(struct xfs_inode *ip, int whichfork);

index 338b9d9984e0..d7275075878e 100644
@@ -329,7 +329,7 @@ xfs_map_blocks(
 	 * mechanism to protect us from arbitrary extent modifying contexts, not
 	 * just eofblocks.
 	 */
-	xfs_trim_extent_eof(&wpc->imap, ip);
+	xfs_trim_extent(&wpc->imap, 0, XFS_B_TO_FSB(mp, i_size_read(inode)));
 
 	/*
 	 * COW fork blocks can overlap data fork blocks even if the blocks

index d7275075878e..8fec6fd4c632 100644
@@ -28,7 +28,7 @@
  */
 struct xfs_writepage_ctx {
 	struct xfs_bmbt_irec    imap;
-	unsigned int		io_type;
+	int			fork;
 	unsigned int		cow_seq;
 	struct xfs_ioend	*ioend;
 };

@@ -255,30 +255,20 @@ xfs_end_io(
 	 */
 	error = blk_status_to_errno(ioend->io_bio->bi_status);
 	if (unlikely(error)) {
-		switch (ioend->io_type) {
-		case XFS_IO_COW:
+		if (ioend->io_fork == XFS_COW_FORK)
 			xfs_reflink_cancel_cow_range(ip, offset, size, true);
-			break;
-		}
-
 		goto done;
 	}
 
 	/*
-	 * Success:  commit the COW or unwritten blocks if needed.
+	 * Success: commit the COW or unwritten blocks if needed.
 	 */
-	switch (ioend->io_type) {
-	case XFS_IO_COW:
+	if (ioend->io_fork == XFS_COW_FORK)
 		error = xfs_reflink_end_cow(ip, offset, size);
-		break;
-	case XFS_IO_UNWRITTEN:
-		/* writeback should never update isize */
+	else if (ioend->io_state == XFS_EXT_UNWRITTEN)
 		error = xfs_iomap_write_unwritten(ip, offset, size, false);
-		break;
-	default:
+	else
 		ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);
-		break;
-	}
 
 done:
 	if (ioend->io_append_trans)

@@ -293,7 +283,8 @@ xfs_end_bio(
 	struct xfs_ioend	*ioend = bio->bi_private;
 	struct xfs_mount	*mp = XFS_I(ioend->io_inode)->i_mount;
 
-	if (ioend->io_type == XFS_IO_UNWRITTEN || ioend->io_type == XFS_IO_COW)
+	if (ioend->io_fork == XFS_COW_FORK ||
+	    ioend->io_state == XFS_EXT_UNWRITTEN)
 		queue_work(mp->m_unwritten_workqueue, &ioend->io_work);
 	else if (ioend->io_append_trans)
 		queue_work(mp->m_data_workqueue, &ioend->io_work);

@@ -313,7 +304,6 @@ xfs_map_blocks(
 	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset), end_fsb;
 	xfs_fileoff_t		cow_fsb = NULLFILEOFF;
 	struct xfs_bmbt_irec	imap;
-	int			whichfork = XFS_DATA_FORK;
 	struct xfs_iext_cursor	icur;
 	bool			imap_valid;
 	int			error = 0;

@@ -350,7 +340,7 @@ xfs_map_blocks(
 		     offset_fsb < wpc->imap.br_startoff + wpc->imap.br_blockcount;
 	if (imap_valid &&
 	    (!xfs_inode_has_cow_data(ip) ||
-	     wpc->io_type == XFS_IO_COW ||
+	     wpc->fork == XFS_COW_FORK ||
 	     wpc->cow_seq == READ_ONCE(ip->i_cowfp->if_seq)))
 		return 0;
 

@@ -382,6 +372,9 @@ xfs_map_blocks(
 	if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
 		wpc->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
 		xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+		wpc->fork = XFS_COW_FORK;
+
 		/*
 		 * Truncate can race with writeback since writeback doesn't
 		 * take the iolock and truncate decreases the file size before

@@ -394,11 +387,13 @@ xfs_map_blocks(
 		 * will kill the contents anyway.
 		 */
 		if (offset > i_size_read(inode)) {
-			wpc->io_type = XFS_IO_HOLE;
+			wpc->imap.br_blockcount = end_fsb - offset_fsb;
+			wpc->imap.br_startoff = offset_fsb;
+			wpc->imap.br_startblock = HOLESTARTBLOCK;
+			wpc->imap.br_state = XFS_EXT_NORM;
 			return 0;
 		}
-		whichfork = XFS_COW_FORK;
-		wpc->io_type = XFS_IO_COW;
+
 		goto allocate_blocks;
 	}
 

@@ -419,12 +414,14 @@ xfs_map_blocks(
 		imap.br_startoff = end_fsb;	/* fake a hole past EOF */
 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
 
+	wpc->fork = XFS_DATA_FORK;
+
 	if (imap.br_startoff > offset_fsb) {
 		/* landed in a hole or beyond EOF */
 		imap.br_blockcount = imap.br_startoff - offset_fsb;
 		imap.br_startoff = offset_fsb;
 		imap.br_startblock = HOLESTARTBLOCK;
-		wpc->io_type = XFS_IO_HOLE;
+		imap.br_state = XFS_EXT_NORM;
 	} else {
 		/*
 		 * Truncate to the next COW extent if there is one.  This is the

@@ -436,30 +433,23 @@ xfs_map_blocks(
 		    cow_fsb < imap.br_startoff + imap.br_blockcount)
 			imap.br_blockcount = cow_fsb - imap.br_startoff;
 
-		if (isnullstartblock(imap.br_startblock)) {
-			/* got a delalloc extent */
-			wpc->io_type = XFS_IO_DELALLOC;
+		/* got a delalloc extent? */
+		if (isnullstartblock(imap.br_startblock))
 			goto allocate_blocks;
-		}
-
-		if (imap.br_state == XFS_EXT_UNWRITTEN)
-			wpc->io_type = XFS_IO_UNWRITTEN;
-		else
-			wpc->io_type = XFS_IO_OVERWRITE;
 	}
 
 	wpc->imap = imap;
-	trace_xfs_map_blocks_found(ip, offset, count, wpc->io_type, &imap);
+	trace_xfs_map_blocks_found(ip, offset, count, wpc->fork, &imap);
 	return 0;
 allocate_blocks:
-	error = xfs_iomap_write_allocate(ip, whichfork, offset, &imap,
+	error = xfs_iomap_write_allocate(ip, wpc->fork, offset, &imap,
 			&wpc->cow_seq);
 	if (error)
 		return error;
-	ASSERT(whichfork == XFS_COW_FORK || cow_fsb == NULLFILEOFF ||
+	ASSERT(wpc->fork == XFS_COW_FORK || cow_fsb == NULLFILEOFF ||
 	       imap.br_startoff + imap.br_blockcount <= cow_fsb);
 	wpc->imap = imap;
-	trace_xfs_map_blocks_alloc(ip, offset, count, wpc->io_type, &imap);
+	trace_xfs_map_blocks_alloc(ip, offset, count, wpc->fork, &imap);
 	return 0;
 }
 

@@ -484,7 +474,7 @@ xfs_submit_ioend(
 	int			status)
 {
 	/* Convert CoW extents to regular */
-	if (!status && ioend->io_type == XFS_IO_COW) {
+	if (!status && ioend->io_fork == XFS_COW_FORK) {
 		/*
 		 * Yuk. This can do memory allocation, but is not a
 		 * transactional operation so everything is done in GFP_KERNEL

@@ -502,7 +492,8 @@ xfs_submit_ioend(
 
 	/* Reserve log space if we might write beyond the on-disk inode size. */
 	if (!status &&
-	    ioend->io_type != XFS_IO_UNWRITTEN &&
+	    (ioend->io_fork == XFS_COW_FORK ||
+	     ioend->io_state != XFS_EXT_UNWRITTEN) &&
 	    xfs_ioend_is_append(ioend) &&
 	    !ioend->io_append_trans)
 		status = xfs_setfilesize_trans_alloc(ioend);

@@ -531,7 +522,8 @@ xfs_submit_ioend(
 static struct xfs_ioend *
 xfs_alloc_ioend(
 	struct inode		*inode,
-	unsigned int		type,
+	int			fork,
+	xfs_exntst_t		state,
 	xfs_off_t		offset,
 	struct block_device	*bdev,
 	sector_t		sector)

@@ -545,7 +537,8 @@ xfs_alloc_ioend(
 
 	ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
 	INIT_LIST_HEAD(&ioend->io_list);
-	ioend->io_type = type;
+	ioend->io_fork = fork;
+	ioend->io_state = state;
 	ioend->io_inode = inode;
 	ioend->io_size = 0;
 	ioend->io_offset = offset;

@@ -606,13 +599,15 @@ xfs_add_to_ioend(
 	sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
 		((offset - XFS_FSB_TO_B(mp, wpc->imap.br_startoff)) >> 9);
 
-	if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type ||
+	if (!wpc->ioend ||
+	    wpc->fork != wpc->ioend->io_fork ||
+	    wpc->imap.br_state != wpc->ioend->io_state ||
 	    sector != bio_end_sector(wpc->ioend->io_bio) ||
 	    offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
 		if (wpc->ioend)
 			list_add(&wpc->ioend->io_list, iolist);
-		wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset,
-				bdev, sector);
+		wpc->ioend = xfs_alloc_ioend(inode, wpc->fork,
+				wpc->imap.br_state, offset, bdev, sector);
 	}
 
 	if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {

@@ -721,7 +716,7 @@ xfs_writepage_map(
 		error = xfs_map_blocks(wpc, inode, file_offset);
 		if (error)
 			break;
-		if (wpc->io_type == XFS_IO_HOLE)
+		if (wpc->imap.br_startblock == HOLESTARTBLOCK)
 			continue;
 		xfs_add_to_ioend(inode, file_offset, page, iop, wpc, wbc,
 				 &submit_list);

@@ -916,9 +911,7 @@ xfs_vm_writepage(
 	struct page		*page,
 	struct writeback_control *wbc)
 {
-	struct xfs_writepage_ctx wpc = {
-		.io_type = XFS_IO_HOLE,
-	};
+	struct xfs_writepage_ctx wpc = { };
 	int			ret;
 
 	ret = xfs_do_writepage(page, wbc, &wpc);

@@ -932,9 +925,7 @@ xfs_vm_writepages(
 	struct address_space	*mapping,
 	struct writeback_control *wbc)
 {
-	struct xfs_writepage_ctx wpc = {
-		.io_type = XFS_IO_HOLE,
-	};
+	struct xfs_writepage_ctx wpc = { };
 	int			ret;
 
 	xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);

index 494b4338446e..6c2615b83c5d 100644
@@ -8,30 +8,13 @@
 
 extern struct bio_set xfs_ioend_bioset;
 
-/*
- * Types of I/O for bmap clustering and I/O completion tracking.
- */
-enum {
-	XFS_IO_HOLE,		/* covers region without any block allocation */
-	XFS_IO_DELALLOC,	/* covers delalloc region */
-	XFS_IO_UNWRITTEN,	/* covers allocated but uninitialized data */
-	XFS_IO_OVERWRITE,	/* covers already allocated extent */
-	XFS_IO_COW,		/* covers copy-on-write extent */
-};
-
-#define XFS_IO_TYPES \
-	{ XFS_IO_HOLE,			"hole" },	\
-	{ XFS_IO_DELALLOC,		"delalloc" },	\
-	{ XFS_IO_UNWRITTEN,		"unwritten" },	\
-	{ XFS_IO_OVERWRITE,		"overwrite" },	\
-	{ XFS_IO_COW,			"CoW" }
-
 /*
  * Structure for buffered I/O completions.
  */
 struct xfs_ioend {
 	struct list_head	io_list;	/* next ioend in chain */
-	unsigned int		io_type;	/* delalloc / unwritten */
+	int			io_fork;	/* inode fork written back */
+	xfs_exntst_t		io_state;	/* extent state */
 	struct inode		*io_inode;	/* file being written to */
 	size_t			io_size;	/* size of the extent */
 	xfs_off_t		io_offset;	/* offset in the file */

index 27c93b5f029d..32a7c169e096 100644
@@ -575,7 +575,7 @@ xfs_file_iomap_begin_delay(
 				goto out_unlock;
 		}
 
-		trace_xfs_iomap_found(ip, offset, count, 0, &got);
+		trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK, &got);
 		goto done;
 	}
 

@@ -647,7 +647,7 @@ xfs_file_iomap_begin_delay(
 	 * them out if the write happens to fail.
 	 */
 	iomap->flags |= IOMAP_F_NEW;
-	trace_xfs_iomap_alloc(ip, offset, count, 0, &got);
+	trace_xfs_iomap_alloc(ip, offset, count, XFS_DATA_FORK, &got);
 done:
 	if (isnullstartblock(got.br_startblock))
 		got.br_startblock = DELAYSTARTBLOCK;

@@ -1139,7 +1139,7 @@ xfs_file_iomap_begin(
 		return error;
 
 	iomap->flags |= IOMAP_F_NEW;
-	trace_xfs_iomap_alloc(ip, offset, length, 0, &imap);
+	trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
 
 out_finish:
 	if (xfs_ipincount(ip) && (ip->i_itemp->ili_fsync_fields

@@ -1155,7 +1155,7 @@ xfs_file_iomap_begin(
 out_found:
 	ASSERT(nimaps);
 	xfs_iunlock(ip, lockmode);
-	trace_xfs_iomap_found(ip, offset, length, 0, &imap);
+	trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
 	goto out_finish;
 
 out_unlock:

index 322a852ce284..a8c32632090c 100644
@@ -1148,7 +1148,7 @@ xfs_reflink_remap_blocks(
 			break;
 		ASSERT(nimaps == 1);
 
-		trace_xfs_reflink_remap_imap(src, srcoff, len, XFS_IO_OVERWRITE,
+		trace_xfs_reflink_remap_imap(src, srcoff, len, XFS_DATA_FORK,
 				&imap);
 
 		/* Translate imap into the destination file. */

index 8a6532aae779..870865913bd8 100644
@@ -1210,15 +1210,15 @@ DEFINE_READPAGE_EVENT(xfs_vm_readpages);
 
 DECLARE_EVENT_CLASS(xfs_imap_class,
 	TP_PROTO(struct xfs_inode *ip, xfs_off_t offset, ssize_t count,
-		 int type, struct xfs_bmbt_irec *irec),
-	TP_ARGS(ip, offset, count, type, irec),
+		 int whichfork, struct xfs_bmbt_irec *irec),
+	TP_ARGS(ip, offset, count, whichfork, irec),
 	TP_STRUCT__entry(
 		__field(dev_t, dev)
 		__field(xfs_ino_t, ino)
 		__field(loff_t, size)
 		__field(loff_t, offset)
 		__field(size_t, count)
-		__field(int, type)
+		__field(int, whichfork)
 		__field(xfs_fileoff_t, startoff)
 		__field(xfs_fsblock_t, startblock)
 		__field(xfs_filblks_t, blockcount)

@@ -1229,33 +1229,33 @@ DECLARE_EVENT_CLASS(xfs_imap_class,
 		__entry->size = ip->i_d.di_size;
 		__entry->offset = offset;
 		__entry->count = count;
-		__entry->type = type;
+		__entry->whichfork = whichfork;
 		__entry->startoff = irec ? irec->br_startoff : 0;
 		__entry->startblock = irec ? irec->br_startblock : 0;
 		__entry->blockcount = irec ? irec->br_blockcount : 0;
 	),
 	TP_printk("dev %d:%d ino 0x%llx size 0x%llx offset 0x%llx count %zd "
-		  "type %s startoff 0x%llx startblock %lld blockcount 0x%llx",
+		  "fork %s startoff 0x%llx startblock %lld blockcount 0x%llx",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->ino,
 		  __entry->size,
 		  __entry->offset,
 		  __entry->count,
-		  __print_symbolic(__entry->type, XFS_IO_TYPES),
+		  __entry->whichfork == XFS_COW_FORK ? "cow" : "data",
 		  __entry->startoff,
 		  (int64_t)__entry->startblock,
 		  __entry->blockcount)
 )
 
-#define DEFINE_IOMAP_EVENT(name)	\
+#define DEFINE_IMAP_EVENT(name)	\
 DEFINE_EVENT(xfs_imap_class, name,	\
 	TP_PROTO(struct xfs_inode *ip, xfs_off_t offset, ssize_t count,	\
-		 int type, struct xfs_bmbt_irec *irec),		\
-	TP_ARGS(ip, offset, count, type, irec))
-DEFINE_IOMAP_EVENT(xfs_map_blocks_found);
-DEFINE_IOMAP_EVENT(xfs_map_blocks_alloc);
-DEFINE_IOMAP_EVENT(xfs_iomap_alloc);
-DEFINE_IOMAP_EVENT(xfs_iomap_found);
+		 int whichfork, struct xfs_bmbt_irec *irec),		\
+	TP_ARGS(ip, offset, count, whichfork, irec))
+DEFINE_IMAP_EVENT(xfs_map_blocks_found);
+DEFINE_IMAP_EVENT(xfs_map_blocks_alloc);
+DEFINE_IMAP_EVENT(xfs_iomap_alloc);
+DEFINE_IMAP_EVENT(xfs_iomap_found);
 
 DECLARE_EVENT_CLASS(xfs_simple_io_class,
 	TP_PROTO(struct xfs_inode *ip, xfs_off_t offset, ssize_t count),

@@ -3055,7 +3055,7 @@ DEFINE_EVENT(xfs_inode_irec_class, name, \
 DEFINE_INODE_EVENT(xfs_reflink_set_inode_flag);
 DEFINE_INODE_EVENT(xfs_reflink_unset_inode_flag);
 DEFINE_ITRUNC_EVENT(xfs_reflink_update_inode_size);
-DEFINE_IOMAP_EVENT(xfs_reflink_remap_imap);
+DEFINE_IMAP_EVENT(xfs_reflink_remap_imap);
 TRACE_EVENT(xfs_reflink_remap_blocks_loop,
 	TP_PROTO(struct xfs_inode *src, xfs_fileoff_t soffset,
 		 xfs_filblks_t len, struct xfs_inode *dest,

index 8fec6fd4c632..5b6fab283316 100644
@@ -301,7 +301,8 @@ xfs_map_blocks(
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
 	ssize_t			count = i_blocksize(inode);
-	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset), end_fsb;
+	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
+	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, offset + count);
 	xfs_fileoff_t		cow_fsb = NULLFILEOFF;
 	struct xfs_bmbt_irec	imap;
 	struct xfs_iext_cursor	icur;

@@ -356,11 +357,6 @@ xfs_map_blocks(
 	xfs_ilock(ip, XFS_ILOCK_SHARED);
 	ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
 	       (ip->i_df.if_flags & XFS_IFEXTENTS));
-	ASSERT(offset <= mp->m_super->s_maxbytes);
-
-	if (offset > mp->m_super->s_maxbytes - count)
-		count = mp->m_super->s_maxbytes - offset;
-	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
 
 	/*
 	 * Check if this is offset is covered by a COW extents, and if yes use