diff options
| -rw-r--r-- | fs/libfs.c | 59 |
1 files changed, 35 insertions, 24 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index 6e8d17e1dc4..cd88abdcb43 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 non-block-device 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 + * FSes that don't need any other processing. i_mutex is assumed to be held. + * Block based filesystems should use generic_write_end(). + * NOTE: Even though i_size might get updated by this function, mark_inode_dirty + * 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); |