Commit 2e9466fc authored by Zhang Yi's avatar Zhang Yi Committed by Theodore Ts'o
Browse files

ext4: make __ext4_block_zero_page_range() support large folio 



The partial block zero range helper __ext4_block_zero_page_range()
currently only supports folios of PAGE_SIZE in size. The calculations
for the start block and the offset within a folio for the given range
are incorrect. Modify the implementation to use offset_in_folio()
instead of directly masking PAGE_SIZE - 1, which will be able to support
for large folios.

Signed-off-by: default avatarZhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250512063319.3539411-4-yi.zhang@huaweicloud.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 16705e52

fs/ext4/inode.c

+3 −4
Original line number Diff line number Diff line
@@ -3746,9 +3746,7 @@ void ext4_set_aops(struct inode *inode) 
static int __ext4_block_zero_page_range(handle_t *handle,

		struct address_space *mapping, loff_t from, loff_t length)

{

	ext4_fsblk_t index = from >> PAGE_SHIFT;

	unsigned offset = from & (PAGE_SIZE-1);

	unsigned blocksize, pos;

	unsigned int offset, blocksize, pos;

	ext4_lblk_t iblock;

	struct inode *inode = mapping->host;

	struct buffer_head *bh;
@@ -3763,13 +3761,14 @@ static int __ext4_block_zero_page_range(handle_t *handle, 


	blocksize = inode->i_sb->s_blocksize;



	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);

	iblock = folio->index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);



	bh = folio_buffers(folio);

	if (!bh)

		bh = create_empty_buffers(folio, blocksize, 0);



	/* Find the buffer that contains "offset" */

	offset = offset_in_folio(folio, from);

	pos = blocksize;

	while (offset >= pos) {

		bh = bh->b_this_page;