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ext4: add new function ext4_block_zero_page_range()

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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: Allison Henderson <achender@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Mingming Cao <cmm@us.ibm.com>
This commit is contained in:
Allison Henderson 2011-05-25 07:41:32 -04:00 committed by Theodore Ts'o
parent 55f020db66
commit 308488518d
2 changed files with 33 additions and 2 deletions
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2
fs/ext4/ext4.h
View File

@ -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_chunk_trans_blocks(struct inode *, int nrblocks);
extern int ext4_block_truncate_page(handle_t *handle, extern int ext4_block_truncate_page(handle_t *handle,
struct address_space *mapping, loff_t from); 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 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
extern qsize_t *ext4_get_reserved_space(struct inode *inode); extern qsize_t *ext4_get_reserved_space(struct inode *inode);
extern void ext4_da_update_reserve_space(struct inode *inode, extern void ext4_da_update_reserve_space(struct inode *inode,

33
fs/ext4/inode.c
View File

@ -3913,10 +3913,31 @@ void ext4_set_aops(struct inode *inode)
*/ */
int ext4_block_truncate_page(handle_t *handle, int ext4_block_truncate_page(handle_t *handle,
struct address_space *mapping, loff_t from) 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; ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1); unsigned offset = from & (PAGE_CACHE_SIZE-1);
unsigned blocksize, length, pos; unsigned blocksize, max, pos;
ext4_lblk_t iblock; ext4_lblk_t iblock;
struct inode *inode = mapping->host; struct inode *inode = mapping->host;
struct buffer_head *bh; struct buffer_head *bh;
@ -3929,7 +3950,15 @@ int ext4_block_truncate_page(handle_t *handle,
return -EINVAL; return -EINVAL;
blocksize = inode->i_sb->s_blocksize; 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); iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
if (!page_has_buffers(page)) if (!page_has_buffers(page))