From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f171.google.com (mail-pd0-f171.google.com [209.85.192.171]) by kanga.kvack.org (Postfix) with ESMTP id 5865990008B for ; Wed, 29 Oct 2014 13:10:13 -0400 (EDT) Received: by mail-pd0-f171.google.com with SMTP id r10so3342173pdi.30 for ; Wed, 29 Oct 2014 10:10:12 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com. [67.231.145.42]) by mx.google.com with ESMTP id ri14si4416182pdb.189.2014.10.29.10.10.11 for ; Wed, 29 Oct 2014 10:10:12 -0700 (PDT) From: Josef Bacik Subject: [PATCH] tmpfs: truncate prealloc blocks past i_size Date: Wed, 29 Oct 2014 13:10:08 -0400 Message-ID: <1414602608-1416-1-git-send-email-jbacik@fb.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: hughd@google.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org One of the rocksdb people noticed that when you do something like this fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 10M) pwrite(fd, buf, 5M, 0) ftruncate(5M) on tmpfs the file would still take up 10M, which lead to super fun issues because we were getting ENOSPC before we thought we should be getting ENOSPC. This patch fixes the problem, and mirrors what all the other fs'es do. I tested it locally to make sure it worked properly with the following xfs_io -f -c "falloc -k 0 10M" -c "pwrite 0 5M" -c "truncate 5M" file Without the patch we have "Blocks: 20480", with the patch we have the correct value of "Blocks: 10240". Thanks, Signed-off-by: Josef Bacik --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index 185836b..79b7fb5 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -574,7 +574,7 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) i_size_write(inode, newsize); inode->i_ctime = inode->i_mtime = CURRENT_TIME; } - if (newsize < oldsize) { + if (newsize <= oldsize) { loff_t holebegin = round_up(newsize, PAGE_SIZE); unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); shmem_truncate_range(inode, newsize, (loff_t)-1); -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org