[PATCH] fs/buffer: Convert return type int to vm_fault_t

[PATCH] fs/buffer: Convert return type int to vm_fault_t

[Souptick Joarder]

Return type of block_page_mkwrite() is converted to
vm_fault_t type. The caller of block_page_mkwrite
inside fs/nilfs2 nilfs_page_mkwrite converted accordingly.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
---
 fs/buffer.c                 | 16 +++++++++-------
 fs/nilfs2/file.c            | 13 ++++++++-----
 include/linux/buffer_head.h |  2 +-
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index be31e28..463aa27 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2456,21 +2456,22 @@ int block_commit_write(struct page *page, unsigned from, unsigned to)
  * Direct callers of this function should protect against filesystem freezing
  * using sb_start_pagefault() - sb_end_pagefault() functions.
  */
-int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
+vm_fault_t block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 			 get_block_t get_block)
 {
 	struct page *page = vmf->page;
 	struct inode *inode = file_inode(vma->vm_file);
 	unsigned long end;
+	vm_fault_t ret;
 	loff_t size;
-	int ret;
+	int err;
 
 	lock_page(page);
 	size = i_size_read(inode);
 	if ((page->mapping != inode->i_mapping) ||
 	    (page_offset(page) > size)) {
 		/* We overload EFAULT to mean page got truncated */
-		ret = -EFAULT;
+		err = -EFAULT;
 		goto out_unlock;
 	}
 
@@ -2480,17 +2481,18 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 	else
 		end = PAGE_SIZE;
 
-	ret = __block_write_begin(page, 0, end, get_block);
-	if (!ret)
-		ret = block_commit_write(page, 0, end);
+	err = __block_write_begin(page, 0, end, get_block);
+	if (!err)
+		err = block_commit_write(page, 0, end);
 
-	if (unlikely(ret < 0))
+	if (unlikely(err < 0))
 		goto out_unlock;
 	set_page_dirty(page);
 	wait_for_stable_page(page);
 	return 0;
 out_unlock:
 	unlock_page(page);
+	ret = block_page_mkwrite_return(err);
 	return ret;
 }
 EXPORT_SYMBOL(block_page_mkwrite);
diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 7da0fac..3733883 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -57,7 +57,8 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
 	struct page *page = vmf->page;
 	struct inode *inode = file_inode(vma->vm_file);
 	struct nilfs_transaction_info ti;
-	int ret = 0;
+	vm_fault_t ret = VM_FAULT_LOCKED;
+	int err = 0;
 
 	if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
 		return VM_FAULT_SIGBUS; /* -ENOSPC */
@@ -67,7 +68,7 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
 	if (page->mapping != inode->i_mapping ||
 	    page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
 		unlock_page(page);
-		ret = -EFAULT;	/* make the VM retry the fault */
+		ret = VM_FAULT_NOPAGE;	/* make the VM retry the fault */
 		goto out;
 	}
 
@@ -99,10 +100,12 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
 	/*
 	 * fill hole blocks
 	 */
-	ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
+	err = nilfs_transaction_begin(inode->i_sb, &ti, 1);
 	/* never returns -ENOMEM, but may return -ENOSPC */
-	if (unlikely(ret))
+	if (unlikely(err)) {
+		ret = block_page_mkwrite_return(err);
 		goto out;
+	}
 
 	file_update_time(vma->vm_file);
 	ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
@@ -117,7 +120,7 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
 	wait_for_stable_page(page);
  out:
 	sb_end_pagefault(inode->i_sb);
-	return block_page_mkwrite_return(ret);
+	return ret;
 }
 
 static const struct vm_operations_struct nilfs_file_vm_ops = {
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 96225a7..1aeeb54 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -239,7 +239,7 @@ int cont_write_begin(struct file *, struct address_space *, loff_t,
 			get_block_t *, loff_t *);
 int generic_cont_expand_simple(struct inode *inode, loff_t size);
 int block_commit_write(struct page *page, unsigned from, unsigned to);
-int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
+vm_fault_t block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 				get_block_t get_block);
 /* Convert errno to return value from ->page_mkwrite() call */
 static inline int block_page_mkwrite_return(int err)
-- 
1.9.1

Re: [PATCH] fs/buffer: Convert return type int to vm_fault_t

[Jens Axboe]

On 7/28/18 3:50 AM, Souptick Joarder wrote:
>  out_unlock:
>  	unlock_page(page);
> +	ret = block_page_mkwrite_return(err);
>  	return ret;

	return block_page_mkwrite_return(err);

-- 
Jens Axboe

Re: [PATCH] fs/buffer: Convert return type int to vm_fault_t

[Souptick Joarder]

On Sat, Jul 28, 2018 at 8:34 PM, Jens Axboe <axboe@kernel.dk> wrote:
> On 7/28/18 3:50 AM, Souptick Joarder wrote:
>>  out_unlock:
>>       unlock_page(page);
>> +     ret = block_page_mkwrite_return(err);
>>       return ret;
>
>         return block_page_mkwrite_return(err);
>
> --
> Jens Axboe
>

OK, I will post v2.