On Fri, Jun 27, 2025 at 11:03:11AM +0000, 陈涛涛 Taotao Chen wrote:
> diff --git a/fs/exfat/file.c b/fs/exfat/file.c
> index 841a5b18e3df..fdc2fa1e5c41 100644
> --- a/fs/exfat/file.c
> +++ b/fs/exfat/file.c
> @@ -532,10 +532,12 @@ int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
> return blkdev_issue_flush(inode->i_sb->s_bdev);
> }
>
> -static int exfat_extend_valid_size(struct file *file, loff_t new_valid_size)
> +static int exfat_extend_valid_size(const struct kiocb *iocb,
> + loff_t new_valid_size)
> {
> int err;
> loff_t pos;
> + struct file *file = iocb->ki_filp;
> struct inode *inode = file_inode(file);
> struct exfat_inode_info *ei = EXFAT_I(inode);
> struct address_space *mapping = inode->i_mapping;
> @@ -551,14 +553,14 @@ static int exfat_extend_valid_size(struct file *file, loff_t new_valid_size)
> if (pos + len > new_valid_size)
> len = new_valid_size - pos;
>
> - err = ops->write_begin(file, mapping, pos, len, &folio, NULL);
> + err = ops->write_begin(iocb, mapping, pos, len, &folio, NULL);
> if (err)
> goto out;
>
> off = offset_in_folio(folio, pos);
> folio_zero_new_buffers(folio, off, off + len);
>
> - err = ops->write_end(file, mapping, pos, len, len, folio, NULL);
> + err = ops->write_end(iocb, mapping, pos, len, len, folio, NULL);
> if (err < 0)
> goto out;
> pos += len;
> @@ -604,7 +606,7 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
> }
>
> if (pos > valid_size) {
> - ret = exfat_extend_valid_size(file, pos);
> + ret = exfat_extend_valid_size(iocb, pos);
> if (ret < 0 && ret != -ENOSPC) {
> exfat_err(inode->i_sb,
> "write: fail to zero from %llu to %llu(%zd)",
> @@ -655,8 +657,11 @@ static vm_fault_t exfat_page_mkwrite(struct vm_fault *vmf)
> struct file *file = vma->vm_file;
> struct inode *inode = file_inode(file);
> struct exfat_inode_info *ei = EXFAT_I(inode);
> + struct kiocb iocb;
> loff_t start, end;
>
> + init_sync_kiocb(&iocb, file);
> +
> if (!inode_trylock(inode))
> return VM_FAULT_RETRY;
>
> @@ -665,7 +670,7 @@ static vm_fault_t exfat_page_mkwrite(struct vm_fault *vmf)
> start + vma->vm_end - vma->vm_start);
>
> if (ei->valid_size < end) {
> - err = exfat_extend_valid_size(file, end);
> + err = exfat_extend_valid_size(&iocb, end);
> if (err < 0) {
> inode_unlock(inode);
> return vmf_fs_error(err);
This is unnecessary work. The only ->write_begin/write_end that we'll
see here is exfat_write_begin() / exfat_write_end() which don't actually
need iocb (or file). Traditionally we pass NULL in these situations,
but the exfat people probably weren't aware of this convention.
exfat_extend_valid_size() only uses the file it's passed to get the
inode, and both callers already have the inode. So I'd change
exfat_extend_valid_size() to take an inode instead of a file as its
first argument, then you can skip the creation of an iocb in
exfat_page_mkwrite().
