[PATCH v3 1/5] iomap: add iomap_symlink_write

[Jeremy Bingham <jbingham@gmail.com>]

Add a new iomap_symlink_write function as an iomap based equivalent to
page_symlink found in fs/namei.c. This implementation was suggested by
Darrick J. Wong, who also provided the initial implementation that I
only needed to change slightly to get working.

Suggested-by: Darrick J. Wong <djwong@kernel.org>

Signed-off-by: Jeremy Bingham <jbingham@gmail.com>
---
 fs/iomap/buffered-io.c | 31 +++++++++++++++++++++++++++++++
 include/linux/iomap.h  |  4 ++++
 2 files changed, 35 insertions(+)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 276720bc18dc..6f3f79fdbd8b 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -2066,3 +2066,34 @@ iomap_writepages(struct iomap_writepage_ctx *wpc)
 	return error;
 }
 EXPORT_SYMBOL_GPL(iomap_writepages);
+
+int iomap_symlink_write(struct inode *inode, const char *target, int len,
+		const struct iomap_ops *ops,
+		const struct iomap_write_ops *write_ops, void *private)
+{
+	struct kvec vec = {
+		.iov_base	= (void *)target,
+		.iov_len	= len,
+	};
+	struct iomap_iter iter = {
+		.inode		= inode,
+		.pos		= 0,
+		.len		= len,
+		.flags		= IOMAP_WRITE,
+		.private	= private,
+	};
+	struct iov_iter iov;
+	int ret;
+
+	iov_iter_kvec(&iov, ITER_SOURCE, &vec, 1, len);
+
+	while ((ret = iomap_iter(&iter, ops)) > 0)
+		iter.status = iomap_write_iter(&iter, &iov, write_ops);
+
+	if (unlikely(iter.pos == 0))
+		return ret;
+
+	mark_inode_dirty(inode);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_symlink_write);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 56b43d594e6e..9274fa256bc9 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -393,6 +393,10 @@ loff_t iomap_seek_data(struct inode *inode, loff_t offset,
 sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
 		const struct iomap_ops *ops);
 
+int iomap_symlink_write(struct inode *inode, const char *target, int len,
+		const struct iomap_ops *ops,
+		const struct iomap_write_ops *write_ops, void *private);
+
 /*
  * Flags for iomap_ioend->io_flags.
  */
-- 
2.47.3