From 6c2ae0d5db57d772a11f2d7399da5e22f94767d6 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 28 Apr 2022 23:59:15 -0400 Subject: buffer: Rewrite nobh_truncate_page() to use folios - Calculate iblock directly instead of using a while loop - Move has_buffers to the end to remove a backwards jump - Use __filemap_get_folio() instead of grab_cache_page(), which removes a spurious FGP_ACCESSED flag. - Eliminate length and pos variables - Use folio APIs where they exist Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig --- fs/buffer.c | 64 ++++++++++++++++++++++++++----------------------------------- 1 file changed, 27 insertions(+), 37 deletions(-) (limited to 'fs/buffer.c') diff --git a/fs/buffer.c b/fs/buffer.c index fb4df259c92d..9737e0dbe3ec 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2791,44 +2791,28 @@ int nobh_truncate_page(struct address_space *mapping, loff_t from, get_block_t *get_block) { pgoff_t index = from >> PAGE_SHIFT; - unsigned offset = from & (PAGE_SIZE-1); - unsigned blocksize; - sector_t iblock; - unsigned length, pos; struct inode *inode = mapping->host; - struct page *page; + unsigned blocksize = i_blocksize(inode); + struct folio *folio; struct buffer_head map_bh; + size_t offset; + sector_t iblock; int err; - blocksize = i_blocksize(inode); - length = offset & (blocksize - 1); - /* Block boundary? Nothing to do */ - if (!length) + if (!(from & (blocksize - 1))) return 0; - length = blocksize - length; - iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits); - - page = grab_cache_page(mapping, index); + folio = __filemap_get_folio(mapping, index, FGP_LOCK | FGP_CREAT, + mapping_gfp_mask(mapping)); err = -ENOMEM; - if (!page) + if (!folio) goto out; - if (page_has_buffers(page)) { -has_buffers: - unlock_page(page); - put_page(page); - return block_truncate_page(mapping, from, get_block); - } - - /* Find the buffer that contains "offset" */ - pos = blocksize; - while (offset >= pos) { - iblock++; - pos += blocksize; - } + if (folio_buffers(folio)) + goto has_buffers; + iblock = from >> inode->i_blkbits; map_bh.b_size = blocksize; map_bh.b_state = 0; err = get_block(inode, iblock, &map_bh, 0); @@ -2839,29 +2823,35 @@ has_buffers: goto unlock; /* Ok, it's mapped. Make sure it's up-to-date */ - if (!PageUptodate(page)) { - err = mapping->a_ops->readpage(NULL, page); + if (!folio_test_uptodate(folio)) { + err = mapping->a_ops->readpage(NULL, &folio->page); if (err) { - put_page(page); + folio_put(folio); goto out; } - lock_page(page); - if (!PageUptodate(page)) { + folio_lock(folio); + if (!folio_test_uptodate(folio)) { err = -EIO; goto unlock; } - if (page_has_buffers(page)) + if (folio_buffers(folio)) goto has_buffers; } - zero_user(page, offset, length); - set_page_dirty(page); + offset = offset_in_folio(folio, from); + folio_zero_segment(folio, offset, round_up(offset, blocksize)); + folio_mark_dirty(folio); err = 0; unlock: - unlock_page(page); - put_page(page); + folio_unlock(folio); + folio_put(folio); out: return err; + +has_buffers: + folio_unlock(folio); + folio_put(folio); + return block_truncate_page(mapping, from, get_block); } EXPORT_SYMBOL(nobh_truncate_page); -- cgit v1.2.3