From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757266AbaIQWVi (ORCPT ); Wed, 17 Sep 2014 18:21:38 -0400 Received: from mail-qc0-f170.google.com ([209.85.216.170]:48252 "EHLO mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757067AbaIQWVF (ORCPT ); Wed, 17 Sep 2014 18:21:05 -0400 From: Milosz Tanski To: linux-kernel@vger.kernel.org Cc: Christoph Hellwig , Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, Mel Gorman , Volker Lendecke , Tejun Heo , Jeff Moyer , "Theodore Ts'o" , Al Viro Subject: [RFC v2 5/5] Check for O_NONBLOCK in all read_iter instances Date: Wed, 17 Sep 2014 22:20:50 +0000 Message-Id: <5d2507ee57b30987a1bbd495dce565f4ef86fdef.1410983999.git.milosz@adfin.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christoph Hellwig Go through filesystem paths and return EAGAIN if there's an operation (like metadata) that would cause blocking. Signed-off-by: Milosz Tanski --- fs/cifs/file.c | 6 ++++++ fs/ocfs2/file.c | 6 ++++++ fs/pipe.c | 3 ++- fs/read_write.c | 17 +++++++++++------ fs/xfs/xfs_file.c | 4 ++++ mm/shmem.c | 4 ++++ 6 files changed, 33 insertions(+), 7 deletions(-) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 7c018a1..e7169ba 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -3005,6 +3005,9 @@ ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to) struct cifs_readdata *rdata, *tmp; struct list_head rdata_list; + if (iocb->ki_rwflags & RWF_NONBLOCK) + return -EAGAIN; + len = iov_iter_count(to); if (!len) return 0; @@ -3123,6 +3126,9 @@ cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to) ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0)) return generic_file_read_iter(iocb, to); + if (iocb->ki_rwflags & RWF_NONBLOCK) + return -EAGAIN; + /* * We need to hold the sem to be sure nobody modifies lock list * with a brlock that prevents reading. diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 2930e23..d96f60d 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -2473,6 +2473,12 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, filp->f_path.dentry->d_name.name, to->nr_segs); /* GRRRRR */ + /* + * No non-blocking reads for ocfs2 for now. Might be doable with + * non-blocking cluster lock helpers. + */ + if (iocb->ki_rwflags & RWF_NONBLOCK) + return -EAGAIN; if (!inode) { ret = -EINVAL; diff --git a/fs/pipe.c b/fs/pipe.c index 21981e5..212bf68 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -302,7 +302,8 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) */ if (ret) break; - if (filp->f_flags & O_NONBLOCK) { + if ((filp->f_flags & O_NONBLOCK) || + (iocb->ki_rwflags & RWF_NONBLOCK)) { ret = -EAGAIN; break; } diff --git a/fs/read_write.c b/fs/read_write.c index 29b5823..a3efa95 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -833,14 +833,19 @@ static ssize_t do_readv_writev(int type, struct file *file, file_start_write(file); } - if (iter_fn) + if (iter_fn) { ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len, pos, iter_fn, flags); - else if (fnv) - ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, - pos, fnv); - else - ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); + } else { + if (type == READ && (flags & RWF_NONBLOCK)) + return -EAGAIN; + + if (fnv) + ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, + pos, fnv); + else + ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); + } if (type != READ) file_end_write(file); diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index de5368c..cf61271 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -246,6 +246,10 @@ xfs_file_read_iter( XFS_STATS_INC(xs_read_calls); + /* XXX: need a non-blocking iolock helper, shouldn't be too hard */ + if (iocb->ki_rwflags & RWF_NONBLOCK) + return -EAGAIN; + if (unlikely(file->f_flags & O_DIRECT)) ioflags |= XFS_IO_ISDIRECT; if (file->f_mode & FMODE_NOCMTIME) diff --git a/mm/shmem.c b/mm/shmem.c index 0e5fb22..ca2cae2 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1531,6 +1531,10 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) ssize_t retval = 0; loff_t *ppos = &iocb->ki_pos; + /* XXX: should be easily supportable */ + if (iocb->ki_rwflags & RWF_NONBLOCK) + return -EAGAIN; + /* * Might this read be for a stacking filesystem? Then when reading * holes of a sparse file, we actually need to allocate those pages, -- 2.1.0