[RFC PATCH v4 26/34] ext4: implement mmap iomap path

Zhang Yi
2024-04-10T14:38:45Z

Add ext4_iomap_page_mkwrite() for the mmap iomap path. It dirty folio
and map blocks, almost all work have been done in iomap_page_mkwrite(),
so call it directly.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
fs/ext4/inode.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 55a4d293177d..9d694c780007 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -6484,6 +6484,26 @@ static int ext4_bh_unmapped(handle_t *handle, struct inode *inode,
return !buffer_mapped(bh);
}

+static vm_fault_t ext4_iomap_page_mkwrite(struct vm_fault *vmf)
+{
+ struct inode *inode = file_inode(vmf->vma->vm_file);
+ const struct iomap_ops *iomap_ops;
+
+ /*
+ * ext4_nonda_switch() could writeback this folio, so have to
+ * call it before lock folio.
+ *
+ * TODO: drop ext4_nonda_switch() after reserving enough sapce
+ * for metadata and merge delalloc and nodelalloc operations.
+ */
+ if (test_opt(inode->i_sb, DELALLOC) && !ext4_nonda_switch(inode->i_sb))
+ iomap_ops = &ext4_iomap_buffered_da_write_ops;
+ else
+ iomap_ops = &ext4_iomap_buffered_write_ops;
+
+ return iomap_page_mkwrite(vmf, iomap_ops);
+}
+
vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
@@ -6507,6 +6527,11 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)

filemap_invalidate_lock_shared(mapping);

+ if (ext4_test_inode_state(inode, EXT4_STATE_BUFFERED_IOMAP)) {
+ ret = ext4_iomap_page_mkwrite(vmf);
+ goto out;
+ }
+
err = ext4_convert_inline_data(inode);
if (err)
goto out_ret;
--
2.39.2