It's more or less straight-forward. Most changes are around getting offset/len withing page right and zero out desired part of the page.
Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com> --- fs/buffer.c | 70 +++++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 40 insertions(+), 30 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 72462beca909..d05524f14846 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1902,6 +1902,7 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) { unsigned int block_start, block_end; struct buffer_head *head, *bh; + bool uptodate = PageUptodate(page); BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) @@ -1912,21 +1913,21 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) do { block_end = block_start + bh->b_size; - if (buffer_new(bh)) { - if (block_end > from && block_start < to) { - if (!PageUptodate(page)) { - unsigned start, size; + if (buffer_new(bh) && block_end > from && block_start < to) { + if (!uptodate) { + unsigned start, size; - start = max(from, block_start); - size = min(to, block_end) - start; + start = max(from, block_start); + size = min(to, block_end) - start; - zero_user(page, start, size); - set_buffer_uptodate(bh); - } - - clear_buffer_new(bh); - mark_buffer_dirty(bh); + zero_user(page + block_start / PAGE_SIZE, + start % PAGE_SIZE, + size); + set_buffer_uptodate(bh); } + + clear_buffer_new(bh); + mark_buffer_dirty(bh); } block_start = block_end; @@ -1992,18 +1993,21 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh, int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, get_block_t *get_block, struct iomap *iomap) { - unsigned from = pos & (PAGE_SIZE - 1); - unsigned to = from + len; - struct inode *inode = page->mapping->host; + unsigned from, to; + struct inode *inode = page_mapping(page)->host; unsigned block_start, block_end; sector_t block; int err = 0; unsigned blocksize, bbits; struct buffer_head *bh, *head, *wait[2], **wait_bh=wait; + bool uptodate = PageUptodate(page); + page = compound_head(page); + from = pos & ~hpage_mask(page); + to = from + len; BUG_ON(!PageLocked(page)); - BUG_ON(from > PAGE_SIZE); - BUG_ON(to > PAGE_SIZE); + BUG_ON(from > hpage_size(page)); + BUG_ON(to > hpage_size(page)); BUG_ON(from > to); head = create_page_buffers(page, inode, 0); @@ -2016,10 +2020,8 @@ int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, block++, block_start=block_end, bh = bh->b_this_page) { block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { - if (PageUptodate(page)) { - if (!buffer_uptodate(bh)) - set_buffer_uptodate(bh); - } + if (uptodate && !buffer_uptodate(bh)) + set_buffer_uptodate(bh); continue; } if (buffer_new(bh)) @@ -2036,23 +2038,28 @@ int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, if (buffer_new(bh)) { clean_bdev_bh_alias(bh); - if (PageUptodate(page)) { + if (uptodate) { clear_buffer_new(bh); set_buffer_uptodate(bh); mark_buffer_dirty(bh); continue; } - if (block_end > to || block_start < from) - zero_user_segments(page, - to, block_end, - block_start, from); + if (block_end > to || block_start < from) { + BUG_ON(to - from > PAGE_SIZE); + zero_user_segments(page + + block_start / PAGE_SIZE, + to % PAGE_SIZE, + (block_start % PAGE_SIZE) + blocksize, + block_start % PAGE_SIZE, + from % PAGE_SIZE); + } continue; } } - if (PageUptodate(page)) { + if (uptodate) { if (!buffer_uptodate(bh)) set_buffer_uptodate(bh); - continue; + continue; } if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh) && @@ -2089,6 +2096,7 @@ static int __block_commit_write(struct inode *inode, struct page *page, unsigned blocksize; struct buffer_head *bh, *head; + VM_BUG_ON_PAGE(PageTail(page), page); bh = head = page_buffers(page); blocksize = bh->b_size; @@ -2102,7 +2110,8 @@ static int __block_commit_write(struct inode *inode, struct page *page, set_buffer_uptodate(bh); mark_buffer_dirty(bh); } - clear_buffer_new(bh); + if (buffer_new(bh)) + clear_buffer_new(bh); block_start = block_end; bh = bh->b_this_page; @@ -2155,7 +2164,8 @@ int block_write_end(struct file *file, struct address_space *mapping, struct inode *inode = mapping->host; unsigned start; - start = pos & (PAGE_SIZE - 1); + page = compound_head(page); + start = pos & ~hpage_mask(page); if (unlikely(copied < len)) { /* -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html