From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751350AbaBBFn6 (ORCPT ); Sun, 2 Feb 2014 00:43:58 -0500 Received: from mail-pa0-f47.google.com ([209.85.220.47]:49653 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751219AbaBBFnv (ORCPT ); Sun, 2 Feb 2014 00:43:51 -0500 From: Namjae Jeon To: viro@zeniv.linux.org.uk, david@fromorbit.com, bpm@sgi.com, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, mtk.manpages@gmail.com Cc: linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Namjae Jeon , Namjae Jeon , Ashish Sangwan Subject: [PATCH RESEND 1/10] fs: Add new flag(FALLOC_FL_COLLAPSE_RANGE) for fallocate Date: Sun, 2 Feb 2014 14:43:41 +0900 Message-Id: <1391319821-3135-1-git-send-email-linkinjeon@gmail.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Namjae Jeon Add new flag(FALLOC_FL_COLLAPSE_RANGE) for fallocate. updated detailed semantics in comments. Signed-off-by: Namjae Jeon Signed-off-by: Ashish Sangwan --- fs/open.c | 24 +++++++++++++++++++++--- include/uapi/linux/falloc.h | 21 +++++++++++++++++++++ 2 files changed, 42 insertions(+), 3 deletions(-) diff --git a/fs/open.c b/fs/open.c index 4b3e1ed..4a923a5 100644 --- a/fs/open.c +++ b/fs/open.c @@ -231,7 +231,8 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) return -EINVAL; /* Return error if mode is not supported */ - if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | + FALLOC_FL_COLLAPSE_RANGE)) return -EOPNOTSUPP; /* Punch hole must have keep size set */ @@ -239,11 +240,20 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) !(mode & FALLOC_FL_KEEP_SIZE)) return -EOPNOTSUPP; + /* Collapse range should only be used exclusively. */ + if ((mode & FALLOC_FL_COLLAPSE_RANGE) && + (mode & ~FALLOC_FL_COLLAPSE_RANGE)) + return -EINVAL; + if (!(file->f_mode & FMODE_WRITE)) return -EBADF; - /* It's not possible punch hole on append only file */ - if (mode & FALLOC_FL_PUNCH_HOLE && IS_APPEND(inode)) + /* + * It's not possible to punch hole or perform collapse range + * on append only file + */ + if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_COLLAPSE_RANGE) + && IS_APPEND(inode)) return -EPERM; if (IS_IMMUTABLE(inode)) @@ -271,6 +281,14 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) return -EFBIG; + /* + * There is no need to overlap collapse range with EOF, in which case + * it is effectively a truncate operation + */ + if ((mode & FALLOC_FL_COLLAPSE_RANGE) && + (offset + len >= i_size_read(inode))) + return -EINVAL; + if (!file->f_op->fallocate) return -EOPNOTSUPP; diff --git a/include/uapi/linux/falloc.h b/include/uapi/linux/falloc.h index 990c4cc..5b214cc 100644 --- a/include/uapi/linux/falloc.h +++ b/include/uapi/linux/falloc.h @@ -5,5 +5,26 @@ #define FALLOC_FL_PUNCH_HOLE 0x02 /* de-allocates range */ #define FALLOC_FL_NO_HIDE_STALE 0x04 /* reserved codepoint */ +/* + * FALLOC_FL_COLLAPSE_RANGE is used to remove a range of a file + * without leaving a hole in the file. The contents of the file beyond + * the range being removed is appended to the start offset of the range + * being removed (i.e. the hole that was punched is "collapsed"), + * resulting in a file layout that looks like the range that was + * removed never existed. As such collapsing a range of a file changes + * the size of the file, reducing it by the same length of the range + * that has been removed by the operation. + * + * Different filesystems may implement different limitations on the + * granularity of the operation. Most will limit operations to + * filesystem block size boundaries, but this boundary may be larger or + * smaller depending on the filesystem and/or the configuration of the + * filesystem or file. + * + * Attempting to collapse a range that crosses the end of the file is + * considered an illegal operation - just use ftruncate(2) if you need + * to collapse a range that crosses EOF. + */ +#define FALLOC_FL_COLLAPSE_RANGE 0x08 #endif /* _UAPI_FALLOC_H_ */ -- 1.7.9.5