Commit 6e1db88d authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

introduce __block_write_begin 



Split up the block_write_begin implementation - __block_write_begin is a new
trivial wrapper for block_prepare_write that always takes an already
allocated page and can be either called from block_write_begin or filesystem
code that already has a page allocated.  Remove the handling of already
allocated pages from block_write_begin after switching all callers that
do it to __block_write_begin.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f4e420dc

fs/buffer.c

+26 −43
Original line number Diff line number Diff line
@@ -1833,9 +1833,10 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) 
}

EXPORT_SYMBOL(page_zero_new_buffers);



static int __block_prepare_write(struct inode *inode, struct page *page,

		unsigned from, unsigned to, get_block_t *get_block)

int block_prepare_write(struct page *page, unsigned from, unsigned to,

		get_block_t *get_block)

{

	struct inode *inode = page->mapping->host;

	unsigned block_start, block_end;

	sector_t block;

	int err = 0;
@@ -1908,10 +1909,13 @@ static int __block_prepare_write(struct inode *inode, struct page *page, 
		if (!buffer_uptodate(*wait_bh))

			err = -EIO;

	}

	if (unlikely(err))

	if (unlikely(err)) {

		page_zero_new_buffers(page, from, to);

		ClearPageUptodate(page);

	}

	return err;

}

EXPORT_SYMBOL(block_prepare_write);



static int __block_commit_write(struct inode *inode, struct page *page,

		unsigned from, unsigned to)
@@ -1948,6 +1952,15 @@ static int __block_commit_write(struct inode *inode, struct page *page, 
	return 0;

}



int __block_write_begin(struct page *page, loff_t pos, unsigned len,

		get_block_t *get_block)

{

	unsigned start = pos & (PAGE_CACHE_SIZE - 1);



	return block_prepare_write(page, start, start + len, get_block);

}

EXPORT_SYMBOL(__block_write_begin);



/*

 * Filesystems implementing the new truncate sequence should use the

 * _newtrunc postfix variant which won't incorrectly call vmtruncate.
@@ -1958,41 +1971,22 @@ int block_write_begin_newtrunc(struct file *file, struct address_space *mapping, 
			struct page **pagep, void **fsdata,

			get_block_t *get_block)

{

	struct inode *inode = mapping->host;

	int status = 0;

	pgoff_t index = pos >> PAGE_CACHE_SHIFT;

	struct page *page;

	pgoff_t index;

	unsigned start, end;

	int ownpage = 0;



	index = pos >> PAGE_CACHE_SHIFT;

	start = pos & (PAGE_CACHE_SIZE - 1);

	end = start + len;

	int status;



	page = *pagep;

	if (page == NULL) {

		ownpage = 1;

	page = grab_cache_page_write_begin(mapping, index, flags);

		if (!page) {

			status = -ENOMEM;

			goto out;

		}

		*pagep = page;

	} else

		BUG_ON(!PageLocked(page));

	if (!page)

		return -ENOMEM;



	status = __block_prepare_write(inode, page, start, end, get_block);

	status = __block_write_begin(page, pos, len, get_block);

	if (unlikely(status)) {

		ClearPageUptodate(page);



		if (ownpage) {

		unlock_page(page);

		page_cache_release(page);

			*pagep = NULL;

		}

		page = NULL;

	}



out:

	*pagep = page;

	return status;

}

EXPORT_SYMBOL(block_write_begin_newtrunc);
@@ -2379,17 +2373,6 @@ out: 
}

EXPORT_SYMBOL(cont_write_begin);



int block_prepare_write(struct page *page, unsigned from, unsigned to,

			get_block_t *get_block)

{

	struct inode *inode = page->mapping->host;

	int err = __block_prepare_write(inode, page, from, to, get_block);

	if (err)

		ClearPageUptodate(page);

	return err;

}

EXPORT_SYMBOL(block_prepare_write);



int block_commit_write(struct page *page, unsigned from, unsigned to)

{

	struct inode *inode = page->mapping->host;

fs/ext2/dir.c

+1 −2
Original line number Diff line number Diff line
@@ -450,8 +450,7 @@ ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child) 


static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)

{

	return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,

					  &page, NULL, ext2_get_block);

	return __block_write_begin(page, pos, len, ext2_get_block);

}



/* Releases the page */

fs/ext3/inode.c

+1 −2
Original line number Diff line number Diff line
@@ -1196,8 +1196,7 @@ retry: 
		ret = PTR_ERR(handle);

		goto out;

	}

	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,

							ext3_get_block);

	ret = __block_write_begin(page, pos, len, ext3_get_block);

	if (ret)

		goto write_begin_failed;

fs/ext4/inode.c

+4 −7
Original line number Diff line number Diff line
@@ -1578,11 +1578,9 @@ retry: 
	*pagep = page;



	if (ext4_should_dioread_nolock(inode))

		ret = block_write_begin(file, mapping, pos, len, flags, pagep,

				fsdata, ext4_get_block_write);

		ret = __block_write_begin(page, pos, len, ext4_get_block_write);

	else

		ret = block_write_begin(file, mapping, pos, len, flags, pagep,

				fsdata, ext4_get_block);

		ret = __block_write_begin(page, pos, len, ext4_get_block);



	if (!ret && ext4_should_journal_data(inode)) {

		ret = walk_page_buffers(handle, page_buffers(page),
@@ -1593,7 +1591,7 @@ retry: 
		unlock_page(page);

		page_cache_release(page);

		/*

		 * block_write_begin may have instantiated a few blocks

		 * __block_write_begin may have instantiated a few blocks

		 * outside i_size.  Trim these off again. Don't need

		 * i_size_read because we hold i_mutex.

		 *
@@ -3185,8 +3183,7 @@ retry: 
	}

	*pagep = page;



	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,

				ext4_da_get_block_prep);

	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);

	if (ret < 0) {

		unlock_page(page);

		ext4_journal_stop(handle);

fs/minix/inode.c

+1 −2
Original line number Diff line number Diff line
@@ -359,8 +359,7 @@ static int minix_readpage(struct file *file, struct page *page) 


int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)

{

	return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,

					  &page, NULL, minix_get_block);

	return __block_write_begin(page, pos, len, minix_get_block);

}



static int minix_write_begin(struct file *file, struct address_space *mapping,

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