iomap: replace iomap_folio_ops with iomap_write_ops

The iomap_folio_ops are only used for buffered writes, including the zero
and unshare variants.  Rename them to iomap_write_ops to better describe
the usage, and pass them through the call chain like the other operation
specific methods instead of through the iomap.

xfs_iomap_valid grows a IOMAP_HOLE check to keep the existing behavior
that never attached the folio_ops to a iomap representing a hole.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Brian Foster <[email protected]>
Reviewed-by: "Darrick J. Wong" <[email protected]>
Acked-by: Damien Le Moal <[email protected]>

Author: Christoph Hellwig

Documentation/filesystems/iomap/design.rst

@@ -167,7 +167,6 @@ structure below:
      struct dax_device   *dax_dev;
      void                *inline_data;
      void                *private;
-     const struct iomap_folio_ops *folio_ops;
      u64                 validity_cookie;
  };
 
@@ -292,8 +291,6 @@ The fields are as follows:
    <https://lore.kernel.org/all/[email protected]/>`_.
    This value will be passed unchanged to ``->iomap_end``.
 
- * ``folio_ops`` will be covered in the section on pagecache operations.
-
  * ``validity_cookie`` is a magic freshness value set by the filesystem
    that should be used to detect stale mappings.
    For pagecache operations this is critical for correct operation

Documentation/filesystems/iomap/operations.rst

@@ -57,16 +57,12 @@ The following address space operations can be wrapped easily:
  * ``bmap``
  * ``swap_activate``
 
-``struct iomap_folio_ops``
+``struct iomap_write_ops``
 --------------------------
 
-The ``->iomap_begin`` function for pagecache operations may set the
-``struct iomap::folio_ops`` field to an ops structure to override
-default behaviors of iomap:
-
 .. code-block:: c
 
- struct iomap_folio_ops {
+ struct iomap_write_ops {
      struct folio *(*get_folio)(struct iomap_iter *iter, loff_t pos,
                                 unsigned len);
      void (*put_folio)(struct inode *inode, loff_t pos, unsigned copied,

block/fops.c

@@ -723,7 +723,8 @@ blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
 
 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
 {
-	return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL);
+	return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL,
+			NULL);
 }
 
 /*

fs/gfs2/bmap.c

@@ -963,12 +963,16 @@ static struct folio *
 gfs2_iomap_get_folio(struct iomap_iter *iter, loff_t pos, unsigned len)
 {
 	struct inode *inode = iter->inode;
+	struct gfs2_inode *ip = GFS2_I(inode);
 	unsigned int blockmask = i_blocksize(inode) - 1;
 	struct gfs2_sbd *sdp = GFS2_SB(inode);
 	unsigned int blocks;
 	struct folio *folio;
 	int status;
 
+	if (!gfs2_is_jdata(ip) && !gfs2_is_stuffed(ip))
+		return iomap_get_folio(iter, pos, len);
+
 	blocks = ((pos & blockmask) + len + blockmask) >> inode->i_blkbits;
 	status = gfs2_trans_begin(sdp, RES_DINODE + blocks, 0);
 	if (status)
@@ -987,21 +991,22 @@ static void gfs2_iomap_put_folio(struct inode *inode, loff_t pos,
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_sbd *sdp = GFS2_SB(inode);
 
-	if (!gfs2_is_stuffed(ip))
+	if (gfs2_is_jdata(ip) && !gfs2_is_stuffed(ip))
 		gfs2_trans_add_databufs(ip->i_gl, folio,
 					offset_in_folio(folio, pos),
 					copied);
 
 	folio_unlock(folio);
 	folio_put(folio);
 
-	if (tr->tr_num_buf_new)
-		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
-
-	gfs2_trans_end(sdp);
+	if (gfs2_is_jdata(ip) || gfs2_is_stuffed(ip)) {
+		if (tr->tr_num_buf_new)
+			__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
+		gfs2_trans_end(sdp);
+	}
 }
 
-static const struct iomap_folio_ops gfs2_iomap_folio_ops = {
+const struct iomap_write_ops gfs2_iomap_write_ops = {
 	.get_folio = gfs2_iomap_get_folio,
 	.put_folio = gfs2_iomap_put_folio,
 };
@@ -1078,8 +1083,6 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
 		gfs2_trans_end(sdp);
 	}
 
-	if (gfs2_is_stuffed(ip) || gfs2_is_jdata(ip))
-		iomap->folio_ops = &gfs2_iomap_folio_ops;
 	return 0;
 
 out_trans_end:
@@ -1304,7 +1307,7 @@ static int gfs2_block_zero_range(struct inode *inode, loff_t from, loff_t length
 		return 0;
 	length = min(length, inode->i_size - from);
 	return iomap_zero_range(inode, from, length, NULL, &gfs2_iomap_ops,
-			NULL);
+			&gfs2_iomap_write_ops, NULL);
 }
 
 #define GFS2_JTRUNC_REVOKES 8192

fs/gfs2/bmap.h

@@ -44,6 +44,7 @@ static inline void gfs2_write_calc_reserv(const struct gfs2_inode *ip,
 }
 
 extern const struct iomap_ops gfs2_iomap_ops;
+extern const struct iomap_write_ops gfs2_iomap_write_ops;
 extern const struct iomap_writeback_ops gfs2_writeback_ops;
 
 int gfs2_unstuff_dinode(struct gfs2_inode *ip);

fs/gfs2/file.c

@@ -1058,7 +1058,8 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
 	}
 
 	pagefault_disable();
-	ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops, NULL);
+	ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops,
+			&gfs2_iomap_write_ops, NULL);
 	pagefault_enable();
 	if (ret > 0)
 		written += ret;

fs/iomap/buffered-io.c

@@ -736,28 +736,27 @@ static int __iomap_write_begin(const struct iomap_iter *iter, size_t len,
 	return 0;
 }
 
-static struct folio *__iomap_get_folio(struct iomap_iter *iter, size_t len)
+static struct folio *__iomap_get_folio(struct iomap_iter *iter,
+		const struct iomap_write_ops *write_ops, size_t len)
 {
-	const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;
 	loff_t pos = iter->pos;
 
 	if (!mapping_large_folio_support(iter->inode->i_mapping))
 		len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos));
 
-	if (folio_ops && folio_ops->get_folio)
-		return folio_ops->get_folio(iter, pos, len);
-	else
-		return iomap_get_folio(iter, pos, len);
+	if (write_ops && write_ops->get_folio)
+		return write_ops->get_folio(iter, pos, len);
+	return iomap_get_folio(iter, pos, len);
 }
 
-static void __iomap_put_folio(struct iomap_iter *iter, size_t ret,
+static void __iomap_put_folio(struct iomap_iter *iter,
+		const struct iomap_write_ops *write_ops, size_t ret,
 		struct folio *folio)
 {
-	const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;
 	loff_t pos = iter->pos;
 
-	if (folio_ops && folio_ops->put_folio) {
-		folio_ops->put_folio(iter->inode, pos, ret, folio);
+	if (write_ops && write_ops->put_folio) {
+		write_ops->put_folio(iter->inode, pos, ret, folio);
 	} else {
 		folio_unlock(folio);
 		folio_put(folio);
@@ -794,10 +793,10 @@ static int iomap_write_begin_inline(const struct iomap_iter *iter,
  * offset, and length. Callers can optionally pass a max length *plen,
  * otherwise init to zero.
  */
-static int iomap_write_begin(struct iomap_iter *iter, struct folio **foliop,
+static int iomap_write_begin(struct iomap_iter *iter,
+		const struct iomap_write_ops *write_ops, struct folio **foliop,
 		size_t *poffset, u64 *plen)
 {
-	const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;
 	const struct iomap *srcmap = iomap_iter_srcmap(iter);
 	loff_t pos = iter->pos;
 	u64 len = min_t(u64, SIZE_MAX, iomap_length(iter));
@@ -812,7 +811,7 @@ static int iomap_write_begin(struct iomap_iter *iter, struct folio **foliop,
 	if (fatal_signal_pending(current))
 		return -EINTR;
 
-	folio = __iomap_get_folio(iter, len);
+	folio = __iomap_get_folio(iter, write_ops, len);
 	if (IS_ERR(folio))
 		return PTR_ERR(folio);
 
@@ -826,8 +825,8 @@ static int iomap_write_begin(struct iomap_iter *iter, struct folio **foliop,
 	 * could do the wrong thing here (zero a page range incorrectly or fail
 	 * to zero) and corrupt data.
 	 */
-	if (folio_ops && folio_ops->iomap_valid) {
-		bool iomap_valid = folio_ops->iomap_valid(iter->inode,
+	if (write_ops && write_ops->iomap_valid) {
+		bool iomap_valid = write_ops->iomap_valid(iter->inode,
 							 &iter->iomap);
 		if (!iomap_valid) {
 			iter->iomap.flags |= IOMAP_F_STALE;
@@ -853,8 +852,7 @@ static int iomap_write_begin(struct iomap_iter *iter, struct folio **foliop,
 	return 0;
 
 out_unlock:
-	__iomap_put_folio(iter, 0, folio);
-
+	__iomap_put_folio(iter, write_ops, 0, folio);
 	return status;
 }
 
@@ -926,7 +924,8 @@ static bool iomap_write_end(struct iomap_iter *iter, size_t len, size_t copied,
 	return __iomap_write_end(iter->inode, pos, len, copied, folio);
 }
 
-static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
+static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i,
+		const struct iomap_write_ops *write_ops)
 {
 	ssize_t total_written = 0;
 	int status = 0;
@@ -970,7 +969,8 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 			break;
 		}
 
-		status = iomap_write_begin(iter, &folio, &offset, &bytes);
+		status = iomap_write_begin(iter, write_ops, &folio, &offset,
+				&bytes);
 		if (unlikely(status)) {
 			iomap_write_failed(iter->inode, iter->pos, bytes);
 			break;
@@ -999,7 +999,7 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 			i_size_write(iter->inode, pos + written);
 			iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
 		}
-		__iomap_put_folio(iter, written, folio);
+		__iomap_put_folio(iter, write_ops, written, folio);
 
 		if (old_size < pos)
 			pagecache_isize_extended(iter->inode, old_size, pos);
@@ -1032,7 +1032,8 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 
 ssize_t
 iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
-		const struct iomap_ops *ops, void *private)
+		const struct iomap_ops *ops,
+		const struct iomap_write_ops *write_ops, void *private)
 {
 	struct iomap_iter iter = {
 		.inode		= iocb->ki_filp->f_mapping->host,
@@ -1049,7 +1050,7 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
 		iter.flags |= IOMAP_DONTCACHE;
 
 	while ((ret = iomap_iter(&iter, ops)) > 0)
-		iter.status = iomap_write_iter(&iter, i);
+		iter.status = iomap_write_iter(&iter, i, write_ops);
 
 	if (unlikely(iter.pos == iocb->ki_pos))
 		return ret;
@@ -1283,7 +1284,8 @@ void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte,
 }
 EXPORT_SYMBOL_GPL(iomap_write_delalloc_release);
 
-static int iomap_unshare_iter(struct iomap_iter *iter)
+static int iomap_unshare_iter(struct iomap_iter *iter,
+		const struct iomap_write_ops *write_ops)
 {
 	struct iomap *iomap = &iter->iomap;
 	u64 bytes = iomap_length(iter);
@@ -1298,14 +1300,15 @@ static int iomap_unshare_iter(struct iomap_iter *iter)
 		bool ret;
 
 		bytes = min_t(u64, SIZE_MAX, bytes);
-		status = iomap_write_begin(iter, &folio, &offset, &bytes);
+		status = iomap_write_begin(iter, write_ops, &folio, &offset,
+				&bytes);
 		if (unlikely(status))
 			return status;
 		if (iomap->flags & IOMAP_F_STALE)
 			break;
 
 		ret = iomap_write_end(iter, bytes, bytes, folio);
-		__iomap_put_folio(iter, bytes, folio);
+		__iomap_put_folio(iter, write_ops, bytes, folio);
 		if (WARN_ON_ONCE(!ret))
 			return -EIO;
 
@@ -1323,7 +1326,8 @@ static int iomap_unshare_iter(struct iomap_iter *iter)
 
 int
 iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
-		const struct iomap_ops *ops)
+		const struct iomap_ops *ops,
+		const struct iomap_write_ops *write_ops)
 {
 	struct iomap_iter iter = {
 		.inode		= inode,
@@ -1338,7 +1342,7 @@ iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
 
 	iter.len = min(len, size - pos);
 	while ((ret = iomap_iter(&iter, ops)) > 0)
-		iter.status = iomap_unshare_iter(&iter);
+		iter.status = iomap_unshare_iter(&iter, write_ops);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(iomap_file_unshare);
@@ -1357,7 +1361,8 @@ static inline int iomap_zero_iter_flush_and_stale(struct iomap_iter *i)
 	return filemap_write_and_wait_range(mapping, i->pos, end);
 }
 
-static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
+static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero,
+		const struct iomap_write_ops *write_ops)
 {
 	u64 bytes = iomap_length(iter);
 	int status;
@@ -1368,7 +1373,8 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
 		bool ret;
 
 		bytes = min_t(u64, SIZE_MAX, bytes);
-		status = iomap_write_begin(iter, &folio, &offset, &bytes);
+		status = iomap_write_begin(iter, write_ops, &folio, &offset,
+				&bytes);
 		if (status)
 			return status;
 		if (iter->iomap.flags & IOMAP_F_STALE)
@@ -1381,7 +1387,7 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
 		folio_mark_accessed(folio);
 
 		ret = iomap_write_end(iter, bytes, bytes, folio);
-		__iomap_put_folio(iter, bytes, folio);
+		__iomap_put_folio(iter, write_ops, bytes, folio);
 		if (WARN_ON_ONCE(!ret))
 			return -EIO;
 
@@ -1397,7 +1403,8 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
 
 int
 iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
-		const struct iomap_ops *ops, void *private)
+		const struct iomap_ops *ops,
+		const struct iomap_write_ops *write_ops, void *private)
 {
 	struct iomap_iter iter = {
 		.inode		= inode,
@@ -1427,7 +1434,8 @@ iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
 	    filemap_range_needs_writeback(mapping, pos, pos + plen - 1)) {
 		iter.len = plen;
 		while ((ret = iomap_iter(&iter, ops)) > 0)
-			iter.status = iomap_zero_iter(&iter, did_zero);
+			iter.status = iomap_zero_iter(&iter, did_zero,
+					write_ops);
 
 		iter.len = len - (iter.pos - pos);
 		if (ret || !iter.len)
@@ -1458,15 +1466,16 @@ iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
 			continue;
 		}
 
-		iter.status = iomap_zero_iter(&iter, did_zero);
+		iter.status = iomap_zero_iter(&iter, did_zero, write_ops);
 	}
 	return ret;
 }
 EXPORT_SYMBOL_GPL(iomap_zero_range);
 
 int
 iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
-		const struct iomap_ops *ops, void *private)
+		const struct iomap_ops *ops,
+		const struct iomap_write_ops *write_ops, void *private)
 {
 	unsigned int blocksize = i_blocksize(inode);
 	unsigned int off = pos & (blocksize - 1);
@@ -1475,7 +1484,7 @@ iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
 	if (!off)
 		return 0;
 	return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops,
-			private);
+			write_ops, private);
 }
 EXPORT_SYMBOL_GPL(iomap_truncate_page);