From patchwork Tue Aug 20 23:20:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13770633 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 9868A1C8FDD for ; Tue, 20 Aug 2024 23:21:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724196105; cv=none; b=Wu+lhOFexjB4HRQg7qWyJ683cSy1J2Nci1La5cODoid1KIT+cU5jGZY+h6MQJ2moH8ipzDpc0yRltpwr+gLf+vAvfIt3FRx4AgBNpS4xNa/aCAKcJjbH0cu8ywJhKRJ8z9Twzt03uYmpsf8FhsMTxFcajiICA4nfPNU84ipylBg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724196105; c=relaxed/simple; bh=tpadh5ijkCCOsa7M3OJjST6sL5scalK1OFyRewofsGo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WIe6NgEzouv+hPMPz9KIGmEPFfCH31mw68ANEmISPOkZCRDDClPxJZleUEnV0a5dLOjjdlZo0MoilqE0K1gL7QD8ZcF0nP4K/mLc9SofJnhk5FbKqmnHlwL/+5ispsBgVVcDY3qi4v0WSxPIySWzjrhFQ3gHLEBurxmqPNPMx0Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=LXa3BFU2; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LXa3BFU2" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724196102; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9pcRiiH/lYTDVoni9WSyylXIzj+0iyqYBGBDYoCG5zI=; b=LXa3BFU2t9Z4ZRDbgBCo6H0N1BGfDPLVvW2on3nNTfYF0OTulVMHWsX+Vm3yTTHi9KzUhQ Z5p7eDVCRpUvLhjxbVZBqnybNkDzt9V0L5kVMuy8AEslb+FycTfC90LVg8/zbS8Q/ZEusD xeS9UTsrn8jX9OrhBEn2BCnRLw4iXP8= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-329-JolRJguvP_SguD5LijFaFg-1; Tue, 20 Aug 2024 19:21:39 -0400 X-MC-Unique: JolRJguvP_SguD5LijFaFg-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BA9DE19560AD; Tue, 20 Aug 2024 23:21:36 +0000 (UTC) Received: from warthog.procyon.org.uk.com (unknown [10.42.28.30]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A9E6F1955F54; Tue, 20 Aug 2024 23:21:32 +0000 (UTC) From: David Howells To: Christian Brauner Cc: David Howells , Pankaj Raghav , Jeff Layton , Matthew Wilcox , netfs@lists.linux.dev, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Marc Dionne Subject: [PATCH 4/4] netfs: Fix trimming of streaming-write folios in netfs_inval_folio() Date: Wed, 21 Aug 2024 00:20:58 +0100 Message-ID: <20240820232105.3792638-5-dhowells@redhat.com> In-Reply-To: <20240820232105.3792638-1-dhowells@redhat.com> References: <20240820232105.3792638-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 When netfslib writes to a folio that it doesn't have data for, but that data exists on the server, it will make a 'streaming write' whereby it stores data in a folio that is marked dirty, but not uptodate. When it does this, it attaches a record to folio->private to track the dirty region. When truncate() or fallocate() wants to invalidate part of such a folio, it will call into ->invalidate_folio(), specifying the part of the folio that is to be invalidated. netfs_invalidate_folio(), on behalf of the filesystem, must then determine how to trim the streaming write record. In a couple of cases, however, it does this incorrectly (the reduce-length and move-start cases are switched over and don't, in any case, calculate the value correctly). Fix this by making the logic tree more obvious and fixing the cases. Fixes: 9ebff83e6481 ("netfs: Prep to use folio->private for write grouping and streaming write") Signed-off-by: David Howells cc: Matthew Wilcox (Oracle) cc: Pankaj Raghav cc: Jeff Layton cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org --- fs/netfs/misc.c | 50 ++++++++++++++++++++++++++++++++++--------------- 1 file changed, 35 insertions(+), 15 deletions(-) diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index 69324761fcf7..c1f321cf5999 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -97,10 +97,20 @@ EXPORT_SYMBOL(netfs_clear_inode_writeback); void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) { struct netfs_folio *finfo; + struct netfs_inode *ctx = netfs_inode(folio_inode(folio)); size_t flen = folio_size(folio); _enter("{%lx},%zx,%zx", folio->index, offset, length); + if (offset == 0 && length == flen) { + unsigned long long i_size = i_size_read(&ctx->inode); + unsigned long long fpos = folio_pos(folio), end; + + end = umin(fpos + flen, i_size); + if (fpos < i_size && end > ctx->zero_point) + ctx->zero_point = end; + } + folio_wait_private_2(folio); /* [DEPRECATED] */ if (!folio_test_private(folio)) @@ -115,18 +125,34 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) /* We have a partially uptodate page from a streaming write. */ unsigned int fstart = finfo->dirty_offset; unsigned int fend = fstart + finfo->dirty_len; - unsigned int end = offset + length; + unsigned int iend = offset + length; if (offset >= fend) return; - if (end <= fstart) + if (iend <= fstart) + return; + + /* The invalidation region overlaps the data. If the region + * covers the start of the data, we either move along the start + * or just erase the data entirely. + */ + if (offset <= fstart) { + if (iend >= fend) + goto erase_completely; + /* Move the start of the data. */ + finfo->dirty_len = fend - iend; + finfo->dirty_offset = offset; + return; + } + + /* Reduce the length of the data if the invalidation region + * covers the tail part. + */ + if (iend >= fend) { + finfo->dirty_len = offset - fstart; return; - if (offset <= fstart && end >= fend) - goto erase_completely; - if (offset <= fstart && end > fstart) - goto reduce_len; - if (offset > fstart && end >= fend) - goto move_start; + } + /* A partial write was split. The caller has already zeroed * it, so just absorb the hole. */ @@ -139,12 +165,6 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) folio_clear_uptodate(folio); kfree(finfo); return; -reduce_len: - finfo->dirty_len = offset + length - finfo->dirty_offset; - return; -move_start: - finfo->dirty_len -= offset - finfo->dirty_offset; - finfo->dirty_offset = offset; } EXPORT_SYMBOL(netfs_invalidate_folio); @@ -164,7 +184,7 @@ bool netfs_release_folio(struct folio *folio, gfp_t gfp) if (folio_test_dirty(folio)) return false; - end = folio_pos(folio) + folio_size(folio); + end = umin(folio_pos(folio) + folio_size(folio), i_size_read(&ctx->inode)); if (end > ctx->zero_point) ctx->zero_point = end;