On Wed, 30 Dec 2009 17:40:35 +0200 Boaz Harrosh wrote:
>
> * simple_commit_write was only called by simple_write_end.
> Open coding it makes it tiny bit less heavy on the arithmetic and
> much more readable.
>
> * While at it use zero_user() for clearing a partial page.
> * While at it add a docbook comment for simple_write_end.
Yep, thanks.
> Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
> ---
> fs/libfs.c | 59 +++++++++++++++++++++++++++++++++++------------------------
> 1 files changed, 35 insertions(+), 24 deletions(-)
>
> diff --git a/fs/libfs.c b/fs/libfs.c
> index 6e8d17e..4afb933 100644
> --- a/fs/libfs.c
> +++ b/fs/libfs.c
> @@ -370,40 +370,51 @@ int simple_write_begin(struct file *file, struct address_space *mapping,
> return simple_prepare_write(file, page, from, from+len);
> }
>
> -static int simple_commit_write(struct file *file, struct page *page,
> - unsigned from, unsigned to)
> -{
> - struct inode *inode = page->mapping->host;
> - loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
> -
> - if (!PageUptodate(page))
> - SetPageUptodate(page);
> - /*
> - * No need to use i_size_read() here, the i_size
> - * cannot change under us because we hold the i_mutex.
> - */
> - if (pos > inode->i_size)
> - i_size_write(inode, pos);
> - set_page_dirty(page);
> - return 0;
> -}
> -
> +/**
> + * simple_write_end - .write_end helper for none block-device FSs
for non-block-device FSes
(well, I would spell it "FSes")
> + * @available: See .write_end of address_space_operations
> + * @file: "
> + * @mapping: "
> + * @pos: "
> + * @len: "
> + * @copied: "
> + * @page: "
> + * @fsdata: "
> + *
> + * simple_write_end does the minimum needed for updating a page after writing is
> + * done. It has the same API signature as the .write_end of
> + * address_space_operations vector. So it can just be set onto .write_end for
> + * FSs that don't need any other processing. i_mutex is assumed to be held.
FSes
> + * Block based filesystems should use generic_write_end().
> + * NOTE: Even though i_size might get updated by this function mark_inode_dirty
function,
> + * is not called, so a filesystem that actually does store data in .write_inode
> + * should extend on what's done here with a call to mark_inode_dirty() in the
> + * case that i_size has changed.
> + **/
*/
> int simple_write_end(struct file *file, struct address_space *mapping,
> loff_t pos, unsigned len, unsigned copied,
> struct page *page, void *fsdata)
> {
> - unsigned from = pos & (PAGE_CACHE_SIZE - 1);
> + struct inode *inode = page->mapping->host;
> + loff_t last_pos = pos + copied;
>
> /* zero the stale part of the page if we did a short copy */
> if (copied < len) {
> - void *kaddr = kmap_atomic(page, KM_USER0);
> - memset(kaddr + from + copied, 0, len - copied);
> - flush_dcache_page(page);
> - kunmap_atomic(kaddr, KM_USER0);
> + unsigned from = pos & (PAGE_CACHE_SIZE - 1);
> +
> + zero_user(page, from + copied, len - copied);
> }
>
> - simple_commit_write(file, page, from, from+copied);
> + if (!PageUptodate(page))
> + SetPageUptodate(page);
> + /*
> + * No need to use i_size_read() here, the i_size
> + * cannot change under us because we hold the i_mutex.
> + */
> + if (last_pos > inode->i_size)
> + i_size_write(inode, last_pos);
>
> + set_page_dirty(page);
> unlock_page(page);
> page_cache_release(page);
>
> --
> 1.6.5.2
---
~Randy
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