This patch adds routines needed to zero out the
unblock aligned data of the hole.
The existing ext4_block_truncate_page routine that
is used to zero out unblock aligned data from truncate
has been modified to accept a length parameter, and
renamed to ext4_block_zero_page_range.
The 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 existing ext4_block_truncate_page
has now become a wrapper to this function
Signed-off-by: Allison Henderson <[email protected]>
---
:100644 100644 3ba6c31... 95efb4e... M fs/ext4/ext4.h
:100644 100644 f92c58b... 8ce382d... M fs/ext4/inode.c
fs/ext4/ext4.h | 2 ++
fs/ext4/inode.c | 33 +++++++++++++++++++++++++++++++--
2 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 3ba6c31..95efb4e 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1758,6 +1758,8 @@ 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,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index f92c58b..8ce382d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3916,9 +3916,30 @@ 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;
@@ -3931,7 +3952,15 @@ 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))
--
1.7.1
On Sat, 2011-05-07 at 16:54 -0700, Allison Henderson wrote:
> This patch adds routines needed to zero out the
> unblock aligned data of the hole.
>
> The existing ext4_block_truncate_page routine that
> is used to zero out unblock aligned data from truncate
> has been modified to accept a length parameter, and
> renamed to ext4_block_zero_page_range.
>
> The 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 existing ext4_block_truncate_page
> has now become a wrapper to this function
>
> Signed-off-by: Allison Henderson <[email protected]>
I have looked at this patch before, so you could add my reviewed-by here
too.
> ---
> :100644 100644 3ba6c31... 95efb4e... M fs/ext4/ext4.h
> :100644 100644 f92c58b... 8ce382d... M fs/ext4/inode.c
> fs/ext4/ext4.h | 2 ++
> fs/ext4/inode.c | 33 +++++++++++++++++++++++++++++++--
> 2 files changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 3ba6c31..95efb4e 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1758,6 +1758,8 @@ 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,
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index f92c58b..8ce382d 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3916,9 +3916,30 @@ 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;
> @@ -3931,7 +3952,15 @@ 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))