From patchwork Sat Feb 3 07:11:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13543914 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DDC425024B; Sat, 3 Feb 2024 07:12:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706944348; cv=none; b=H0gDXq1kUhgeDU1XqWwVTNqpy7jdlAm0V+Unwd6Hgb5yUYYPKqxCP96xHFQic4w903fmEahlWFUWR87kWrh/HzFxdu7Ctx4bv85e7s2U1UPfBn8JC1JUbB/cAMJZf4f1sXYrWvrrhzBrlT0VwIkJ9gVoLXdd0VC5nxJpMa4geJw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706944348; c=relaxed/simple; bh=11+z648M91LOuAn70D5VUrpWYdA9g8PsbH50zJJGCu4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=r5u+LLhxzZw3xdK+NeZSRWs/b/hzolAMeocimicWdKQ7wrA2a0LzGFDyb4rFClKj+IRsaAUVwldXxMbfLqvTG58MzEBAwhQj+CjBGG4rcruEtuFE+i/ozafOzENQjHenYLNjLXrc6YJioEkUx9cqZdVTK/2BaU5jZvnIFiNdP8U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=DB0SbFi6; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="DB0SbFi6" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=5NQ5foZwClGdjirNb4QF1J+mdWuoRYsiFuyY0APWPYw=; b=DB0SbFi6hUnk1R7j5iigmiLr5N wGakeqVDiyg/3UEtSiSGuXyTjawI0qc+3zilFXplt0yfm3V6765hxCRtqBaCEEbXRu6PmcijL0EwD ohFv1B6Ru53npud78X2mRjKDz+W8KfKClXbYz//sS9Rlej5EBI3FYmzdI0NGMiwddOLtapEwUWLxn xOakmAfp6pz1HZvZdZCjEVNJYQ8OON7wbu3bQautPLcydnJS0vvYHgPkMCCowSEe3fNMXKbop8vzO KCGYuP5WzsvA6ReigLFIw1MRl26nXVPe05zKKDjdM/xBnxIJJYynLn8OYg9q/pGoHyGTfCW9NxHyR jxtv/EuA==; Received: from [89.144.222.32] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1rWACN-0000000Fk4w-1KJm; Sat, 03 Feb 2024 07:12:23 +0000 From: Christoph Hellwig To: linux-mm@kvack.org Cc: Matthew Wilcox , Jan Kara , David Howells , Brian Foster , Christian Brauner , "Darrick J. Wong" , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 05/13] writeback: rework the loop termination condition in write_cache_pages Date: Sat, 3 Feb 2024 08:11:39 +0100 Message-Id: <20240203071147.862076-6-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240203071147.862076-1-hch@lst.de> References: <20240203071147.862076-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Rework the way we deal with the cleanup after the writepage call. First handle the magic AOP_WRITEPAGE_ACTIVATE separately from real error returns to get it out of the way of the actual error handling path. The split the handling on intgrity vs non-integrity branches first, and return early using a goto for the non-ingegrity early loop condition to remove the need for the done and done_index local variables, and for assigning the error to ret when we can just return error directly. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Brian Foster --- mm/page-writeback.c | 84 ++++++++++++++++++--------------------------- 1 file changed, 33 insertions(+), 51 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index c7c494526bc650..88b2c4c111c01b 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2396,13 +2396,12 @@ int write_cache_pages(struct address_space *mapping, void *data) { int ret = 0; - int done = 0; int error; struct folio_batch fbatch; + struct folio *folio; int nr_folios; pgoff_t index; pgoff_t end; /* Inclusive */ - pgoff_t done_index; xa_mark_t tag; folio_batch_init(&fbatch); @@ -2419,8 +2418,7 @@ int write_cache_pages(struct address_space *mapping, } else { tag = PAGECACHE_TAG_DIRTY; } - done_index = index; - while (!done && (index <= end)) { + while (index <= end) { int i; nr_folios = filemap_get_folios_tag(mapping, &index, end, @@ -2430,11 +2428,7 @@ int write_cache_pages(struct address_space *mapping, break; for (i = 0; i < nr_folios; i++) { - struct folio *folio = fbatch.folios[i]; - unsigned long nr; - - done_index = folio->index; - + folio = fbatch.folios[i]; folio_lock(folio); /* @@ -2469,45 +2463,32 @@ int write_cache_pages(struct address_space *mapping, trace_wbc_writepage(wbc, inode_to_bdi(mapping->host)); error = writepage(folio, wbc, data); - nr = folio_nr_pages(folio); - wbc->nr_to_write -= nr; - if (unlikely(error)) { - /* - * Handle errors according to the type of - * writeback. There's no need to continue for - * background writeback. Just push done_index - * past this page so media errors won't choke - * writeout for the entire file. For integrity - * writeback, we must process the entire dirty - * set regardless of errors because the fs may - * still have state to clear for each page. In - * that case we continue processing and return - * the first error. - */ - if (error == AOP_WRITEPAGE_ACTIVATE) { - folio_unlock(folio); - error = 0; - } else if (wbc->sync_mode != WB_SYNC_ALL) { - ret = error; - done_index = folio->index + nr; - done = 1; - break; - } - if (!ret) - ret = error; + wbc->nr_to_write -= folio_nr_pages(folio); + + if (error == AOP_WRITEPAGE_ACTIVATE) { + folio_unlock(folio); + error = 0; } /* - * We stop writing back only if we are not doing - * integrity sync. In case of integrity sync we have to - * keep going until we have written all the pages - * we tagged for writeback prior to entering this loop. + * For integrity writeback we have to keep going until + * we have written all the folios we tagged for + * writeback above, even if we run past wbc->nr_to_write + * or encounter errors. + * We stash away the first error we encounter in + * wbc->saved_err so that it can be retrieved when we're + * done. This is because the file system may still have + * state to clear for each folio. + * + * For background writeback we exit as soon as we run + * past wbc->nr_to_write or encounter the first error. */ - done_index = folio->index + nr; - if (wbc->nr_to_write <= 0 && - wbc->sync_mode == WB_SYNC_NONE) { - done = 1; - break; + if (wbc->sync_mode == WB_SYNC_ALL) { + if (error && !ret) + ret = error; + } else { + if (error || wbc->nr_to_write <= 0) + goto done; } } folio_batch_release(&fbatch); @@ -2524,14 +2505,15 @@ int write_cache_pages(struct address_space *mapping, * of the file if we are called again, which can only happen due to * -ENOMEM from the file system. */ - if (wbc->range_cyclic) { - if (done) - mapping->writeback_index = done_index; - else - mapping->writeback_index = 0; - } - + if (wbc->range_cyclic) + mapping->writeback_index = 0; return ret; + +done: + folio_batch_release(&fbatch); + if (wbc->range_cyclic) + mapping->writeback_index = folio->index + folio_nr_pages(folio); + return error; } EXPORT_SYMBOL(write_cache_pages);