On Wed 27-05-09 21:28:06, Aneesh Kumar K.V wrote:
> Buffer heads outside i_size will be unmapped. So when we
> are doing "walk_page_buffers" limit ourself to i_size.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
The patch looks fine.
Acked-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/ext4/inode.c | 29 ++++++++++++++++++-----------
> 1 files changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 3b07a6c..f0f0065 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -2514,7 +2514,7 @@ static int ext4_da_writepage(struct page *page,
> * all are mapped and non delay. We don't want to
> * do block allocation here.
> */
> - ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
> + ret = block_prepare_write(page, 0, len,
> noalloc_get_block_write);
> if (!ret) {
> page_bufs = page_buffers(page);
> @@ -2536,7 +2536,7 @@ static int ext4_da_writepage(struct page *page,
> return 0;
> }
> /* now mark the buffer_heads as dirty and uptodate */
> - block_commit_write(page, 0, PAGE_CACHE_SIZE);
> + block_commit_write(page, 0, len);
> }
>
> if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
> @@ -3210,6 +3210,8 @@ static int ext4_normal_writepage(struct page *page,
> static int __ext4_journalled_writepage(struct page *page,
> struct writeback_control *wbc)
> {
> + loff_t size;
> + unsigned int len;
> struct address_space *mapping = page->mapping;
> struct inode *inode = mapping->host;
> struct buffer_head *page_bufs;
> @@ -3217,14 +3219,19 @@ static int __ext4_journalled_writepage(struct page *page,
> int ret = 0;
> int err;
>
> - ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
> + size = i_size_read(inode);
> + if (page->index == size >> PAGE_CACHE_SHIFT)
> + len = size & ~PAGE_CACHE_MASK;
> + else
> + len = PAGE_CACHE_SIZE;
> +
> + ret = block_prepare_write(page, 0, len,
> noalloc_get_block_write);
> if (ret != 0)
> goto out_unlock;
>
> page_bufs = page_buffers(page);
> - walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
> - bget_one);
> + walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
> /* As soon as we unlock the page, it can go away, but we have
> * references to buffers so we are safe */
> unlock_page(page);
> @@ -3235,19 +3242,19 @@ static int __ext4_journalled_writepage(struct page *page,
> goto out;
> }
>
> - ret = walk_page_buffers(handle, page_bufs, 0,
> - PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
> + ret = walk_page_buffers(handle, page_bufs, 0, len,
> + NULL, do_journal_get_write_access);
>
> - err = walk_page_buffers(handle, page_bufs, 0,
> - PAGE_CACHE_SIZE, NULL, write_end_fn);
> + err = walk_page_buffers(handle, page_bufs, 0, len,
> + NULL, write_end_fn);
> if (ret == 0)
> ret = err;
> err = ext4_journal_stop(handle);
> if (!ret)
> ret = err;
>
> - walk_page_buffers(handle, page_bufs, 0,
> - PAGE_CACHE_SIZE, NULL, bput_one);
> + walk_page_buffers(handle, page_bufs, 0, len,
> + NULL, bput_one);
> EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
> goto out;
>
> --
> 1.6.3.1.145.gb74d77
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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