[PATCH 01/10] iomap: factor out a iomap_last_written_block helper

Christoph Hellwig
2024-09-23T15:29:13Z

Split out a pice of logic from iomap_file_buffered_write_punch_delalloc
that is useful for all iomap_end implementations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/iomap/buffered-io.c | 13 ++-----------
include/linux/iomap.h | 14 ++++++++++++++
2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 11ea747228aeec..884891ac7a226c 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1280,7 +1280,6 @@ void iomap_file_buffered_write_punch_delalloc(struct inode *inode,
{
loff_t start_byte;
loff_t end_byte;
- unsigned int blocksize = i_blocksize(inode);

if (iomap->type != IOMAP_DELALLOC)
return;
@@ -1289,16 +1288,8 @@ void iomap_file_buffered_write_punch_delalloc(struct inode *inode,
if (!(iomap->flags & IOMAP_F_NEW))
return;

- /*
- * start_byte refers to the first unused block after a short write. If
- * nothing was written, round offset down to point at the first block in
- * the range.
- */
- if (unlikely(!written))
- start_byte = round_down(pos, blocksize);
- else
- start_byte = round_up(pos + written, blocksize);
- end_byte = round_up(pos + length, blocksize);
+ start_byte = iomap_last_written_block(inode, pos, written);
+ end_byte = round_up(pos + length, i_blocksize(inode));

/* Nothing to do if we've written the entire delalloc extent */
if (start_byte >= end_byte)
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 4ad12a3c8bae22..e62df5d93f04de 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -256,6 +256,20 @@ static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i)
return &i->iomap;
}

+/*
+ * Return the file offset for the first unused block after a short write.
+ *
+ * If nothing was written, round offset down to point at the first block in
+ * the range, else round up to include the partially written block.
+ */
+static inline loff_t iomap_last_written_block(struct inode *inode, loff_t pos,
+ ssize_t written)
+{
+ if (unlikely(!written))
+ return round_down(pos, i_blocksize(inode));
+ return round_up(pos + written, i_blocksize(inode));
+}
+
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops, void *private);
int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
--
2.45.2