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Commit 30848851 authored by Allison Henderson's avatar Allison Henderson Committed by Theodore Ts'o
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ext4: add new function ext4_block_zero_page_range() 



This patch modifies the existing ext4_block_truncate_page() function
which was used by the truncate code path, and which zeroes out block
unaligned data, by adding a new length parameter, and renames it to
ext4_block_zero_page_rage().  This function can now be used to zero out the
head of a block, the tail of a block, or the middle
of a block.

The ext4_block_truncate_page() function is now a wrapper to
ext4_block_zero_page_range().

[ext4 punch hole patch series 2/5 v7] 

Signed-off-by: default avatarAllison Henderson <achender@us.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: default avatarMingming Cao <cmm@us.ibm.com>
parent 55f020db

fs/ext4/ext4.h

+2 −0
Original line number Diff line number Diff line
@@ -1825,6 +1825,8 @@ extern int ext4_writepage_trans_blocks(struct inode *); 
extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);

extern int ext4_block_truncate_page(handle_t *handle,

		struct address_space *mapping, loff_t from);

extern int ext4_block_zero_page_range(handle_t *handle,

		struct address_space *mapping, loff_t from, loff_t length);

extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);

extern qsize_t *ext4_get_reserved_space(struct inode *inode);

extern void ext4_da_update_reserve_space(struct inode *inode,

fs/ext4/inode.c

+31 −2
Original line number Diff line number Diff line
@@ -3913,10 +3913,31 @@ void ext4_set_aops(struct inode *inode) 
 */

int ext4_block_truncate_page(handle_t *handle,

		struct address_space *mapping, loff_t from)

{

	unsigned offset = from & (PAGE_CACHE_SIZE-1);

	unsigned length;

	unsigned blocksize;

	struct inode *inode = mapping->host;



	blocksize = inode->i_sb->s_blocksize;

	length = blocksize - (offset & (blocksize - 1));



	return ext4_block_zero_page_range(handle, mapping, from, length);

}



/*

 * ext4_block_zero_page_range() zeros out a mapping of length 'length'

 * starting from file offset 'from'.  The range to be zero'd must

 * be contained with in one block.  If the specified range exceeds

 * the end of the block it will be shortened to end of the block

 * that cooresponds to 'from'

 */

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_CACHE_SHIFT;

	unsigned offset = from & (PAGE_CACHE_SIZE-1);

	unsigned blocksize, length, pos;

	unsigned blocksize, max, pos;

	ext4_lblk_t iblock;

	struct inode *inode = mapping->host;

	struct buffer_head *bh;
@@ -3929,7 +3950,15 @@ int ext4_block_truncate_page(handle_t *handle, 
		return -EINVAL;



	blocksize = inode->i_sb->s_blocksize;

	length = blocksize - (offset & (blocksize - 1));

	max = blocksize - (offset & (blocksize - 1));



	/*

	 * correct length if it does not fall between

	 * 'from' and the end of the block

	 */

	if (length > max || length < 0)

		length = max;



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



	if (!page_has_buffers(page))