From patchwork Mon Jun 27 18:02:21 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Josef Bacik X-Patchwork-Id: 921862 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p5RI3lGP012836 for ; Mon, 27 Jun 2011 18:03:47 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753034Ab1F0SCb (ORCPT ); Mon, 27 Jun 2011 14:02:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11058 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752989Ab1F0SCa (ORCPT ); Mon, 27 Jun 2011 14:02:30 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p5RI2TBD006429 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 27 Jun 2011 14:02:29 -0400 Received: from localhost.localdomain.com (vpn-8-183.rdu.redhat.com [10.11.8.183]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p5RI2RPL014189; Mon, 27 Jun 2011 14:02:27 -0400 From: Josef Bacik To: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, viro@ZenIV.linux.org.uk Subject: [PATCH 1/4] fs: add SEEK_HOLE and SEEK_DATA flags Date: Mon, 27 Jun 2011 14:02:21 -0400 Message-Id: <1309197745-14107-1-git-send-email-josef@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Mon, 27 Jun 2011 18:03:47 +0000 (UTC) This just gets us ready to support the SEEK_HOLE and SEEK_DATA flags. Turns out using fiemap in things like cp cause more problems than it solves, so lets try and give userspace an interface that doesn't suck. We need to match solaris here, and the definitions are *o* If /whence/ is SEEK_HOLE, the offset of the start of the next hole greater than or equal to the supplied offset is returned. The definition of a hole is provided near the end of the DESCRIPTION. *o* If /whence/ is SEEK_DATA, the file pointer is set to the start of the next non-hole file region greater than or equal to the supplied offset. So in the generic case the entire file is data and there is a virtual hole at the end. That means we will just return i_size for SEEK_HOLE and will return the same offset for SEEK_DATA. This is how Solaris does it so we have to do it the same way. Thanks, Signed-off-by: Josef Bacik --- fs/read_write.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 4 +++- 2 files changed, 40 insertions(+), 1 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 5520f8a..d58551e 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -64,6 +64,23 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin) return file->f_pos; offset += file->f_pos; break; + case SEEK_DATA: + /* + * In the generic case the entire file is data, so as long as + * offset isn't at the end of the file then the offset is data. + */ + if (offset >= inode->i_size) + return -ENXIO; + break; + case SEEK_HOLE: + /* + * There is a virtual hole at the end of the file, so as long as + * offset isn't i_size or larger, return i_size. + */ + if (offset >= inode->i_size) + return -ENXIO; + offset = inode->i_size; + break; } if (offset < 0 && !unsigned_offsets(file)) @@ -141,6 +158,26 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin) goto out; } offset += file->f_pos; + break; + case SEEK_DATA: + /* + * In the generic case the entire file is data, so as + * long as offset isn't at the end of the file then the + * offset is data. + */ + if (offset >= inode->i_size) + return -ENXIO; + break; + case SEEK_HOLE: + /* + * There is a virtual hole at the end of the file, so + * as long as offset isn't i_size or larger, return + * i_size. + */ + if (offset >= inode->i_size) + return -ENXIO; + offset = inode->i_size; + break; } retval = -EINVAL; if (offset >= 0 || unsigned_offsets(file)) { diff --git a/include/linux/fs.h b/include/linux/fs.h index 6e73e2e..552cdfe 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -32,7 +32,9 @@ #define SEEK_SET 0 /* seek relative to beginning of file */ #define SEEK_CUR 1 /* seek relative to current file position */ #define SEEK_END 2 /* seek relative to end of file */ -#define SEEK_MAX SEEK_END +#define SEEK_DATA 3 /* seek to the next data */ +#define SEEK_HOLE 4 /* seek to the next hole */ +#define SEEK_MAX SEEK_HOLE struct fstrim_range { __u64 start;