Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754001AbeAKCTU (ORCPT + 1 other); Wed, 10 Jan 2018 21:19:20 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:60552 "EHLO huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753373AbeAKCTT (ORCPT ); Wed, 10 Jan 2018 21:19:19 -0500 Message-ID: <5A56C998.8070801@huawei.com> Date: Thu, 11 Jan 2018 10:19:04 +0800 From: alex chen User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Gang He CC: , , , Subject: Re: [Ocfs2-devel] [PATCH v3 3/3] ocfs2: nowait aio support References: <1514455665-16325-1-git-send-email-ghe@suse.com> <1514455665-16325-4-git-send-email-ghe@suse.com> In-Reply-To: <1514455665-16325-4-git-send-email-ghe@suse.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.26.59] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hi Gang, On 2017/12/28 18:07, Gang He wrote: > Return -EAGAIN if any of the following checks fail for > direct I/O with nowait flag: > Can not get the related locks immediately, > Blocks are not allocated at the write location, it will trigger > block allocation, this will block IO operations. > > Signed-off-by: Gang He > --- > fs/ocfs2/dir.c | 2 +- > fs/ocfs2/dlmglue.c | 20 ++++++++--- > fs/ocfs2/dlmglue.h | 2 +- > fs/ocfs2/file.c | 95 +++++++++++++++++++++++++++++++++++++++----------- > fs/ocfs2/mmap.c | 2 +- > fs/ocfs2/ocfs2_trace.h | 10 +++--- > 6 files changed, 99 insertions(+), 32 deletions(-) > > diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c > index febe631..ea50901 100644 > --- a/fs/ocfs2/dir.c > +++ b/fs/ocfs2/dir.c > @@ -1957,7 +1957,7 @@ int ocfs2_readdir(struct file *file, struct dir_context *ctx) > > trace_ocfs2_readdir((unsigned long long)OCFS2_I(inode)->ip_blkno); > > - error = ocfs2_inode_lock_atime(inode, file->f_path.mnt, &lock_level); > + error = ocfs2_inode_lock_atime(inode, file->f_path.mnt, &lock_level, 1); > if (lock_level && error >= 0) { > /* We release EX lock which used to update atime > * and get PR lock again to reduce contention > diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c > index a68efa3..07e169f 100644 > --- a/fs/ocfs2/dlmglue.c > +++ b/fs/ocfs2/dlmglue.c > @@ -2515,13 +2515,18 @@ int ocfs2_inode_lock_with_page(struct inode *inode, > > int ocfs2_inode_lock_atime(struct inode *inode, > struct vfsmount *vfsmnt, > - int *level) > + int *level, int wait) > { > int ret; > > - ret = ocfs2_inode_lock(inode, NULL, 0); > + if (wait) > + ret = ocfs2_inode_lock(inode, NULL, 0); > + else > + ret = ocfs2_try_inode_lock(inode, NULL, 0); > + > if (ret < 0) { > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > return ret; > } > > @@ -2533,9 +2538,14 @@ int ocfs2_inode_lock_atime(struct inode *inode, > struct buffer_head *bh = NULL; > > ocfs2_inode_unlock(inode, 0); > - ret = ocfs2_inode_lock(inode, &bh, 1); > + if (wait) > + ret = ocfs2_inode_lock(inode, &bh, 1); > + else > + ret = ocfs2_try_inode_lock(inode, &bh, 1); > + > if (ret < 0) { > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > return ret; > } > *level = 1; > diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h > index 05910fc..c83dbb5 100644 > --- a/fs/ocfs2/dlmglue.h > +++ b/fs/ocfs2/dlmglue.h > @@ -123,7 +123,7 @@ void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res *lockres, > void ocfs2_open_unlock(struct inode *inode); > int ocfs2_inode_lock_atime(struct inode *inode, > struct vfsmount *vfsmnt, > - int *level); > + int *level, int wait); > int ocfs2_inode_lock_full_nested(struct inode *inode, > struct buffer_head **ret_bh, > int ex, > diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c > index a1d0510..caef9b1 100644 > --- a/fs/ocfs2/file.c > +++ b/fs/ocfs2/file.c > @@ -140,6 +140,8 @@ static int ocfs2_file_open(struct inode *inode, struct file *file) > spin_unlock(&oi->ip_lock); > } > > + file->f_mode |= FMODE_NOWAIT; > + > leave: > return status; > } > @@ -2132,12 +2134,12 @@ static int ocfs2_prepare_inode_for_refcount(struct inode *inode, > } > > static int ocfs2_prepare_inode_for_write(struct file *file, > - loff_t pos, > - size_t count) > + loff_t pos, size_t count, int wait) > { > - int ret = 0, meta_level = 0; > + int ret = 0, meta_level = 0, overwrite_io = 0; > struct dentry *dentry = file->f_path.dentry; > struct inode *inode = d_inode(dentry); > + struct buffer_head *di_bh = NULL; > loff_t end; > > /* > @@ -2145,13 +2147,40 @@ static int ocfs2_prepare_inode_for_write(struct file *file, > * if we need to make modifications here. > */ > for(;;) { > - ret = ocfs2_inode_lock(inode, NULL, meta_level); > + if (wait) > + ret = ocfs2_inode_lock(inode, NULL, meta_level); > + else > + ret = ocfs2_try_inode_lock(inode, > + overwrite_io ? NULL : &di_bh, meta_level); > if (ret < 0) { > meta_level = -1; > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > goto out; > } > > + /* > + * Check if IO will overwrite allocated blocks in case > + * IOCB_NOWAIT flag is set. > + */ > + if (!wait && !overwrite_io) { > + overwrite_io = 1; > + if (!down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem)) { > + ret = -EAGAIN; > + goto out_unlock; > + } > + > + ret = ocfs2_overwrite_io(inode, di_bh, pos, count); > + brelse(di_bh); > + di_bh = NULL; > + up_read(&OCFS2_I(inode)->ip_alloc_sem); > + if (ret < 0) { > + if (ret != -EAGAIN) > + mlog_errno(ret); > + goto out_unlock; > + } > + } > + > /* Clear suid / sgid if necessary. We do this here > * instead of later in the write path because > * remove_suid() calls ->setattr without any hint that > @@ -2199,7 +2228,9 @@ static int ocfs2_prepare_inode_for_write(struct file *file, > > out_unlock: > trace_ocfs2_prepare_inode_for_write(OCFS2_I(inode)->ip_blkno, > - pos, count); > + pos, count, wait); > + > + brelse(di_bh); > > if (meta_level >= 0) > ocfs2_inode_unlock(inode, meta_level); > @@ -2211,7 +2242,7 @@ static int ocfs2_prepare_inode_for_write(struct file *file, > static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, > struct iov_iter *from) > { > - int direct_io, rw_level; > + int rw_level; > ssize_t written = 0; > ssize_t ret; > size_t count = iov_iter_count(from); > @@ -2223,6 +2254,8 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, > void *saved_ki_complete = NULL; > int append_write = ((iocb->ki_pos + count) >= > i_size_read(inode) ? 1 : 0); > + int direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; > + int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; > > trace_ocfs2_file_aio_write(inode, file, file->f_path.dentry, > (unsigned long long)OCFS2_I(inode)->ip_blkno, > @@ -2230,12 +2263,17 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, > file->f_path.dentry->d_name.name, > (unsigned int)from->nr_segs); /* GRRRRR */ > > + if (!direct_io && nowait) > + return -EOPNOTSUPP; > + > if (count == 0) > return 0; > > - direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; > - > - inode_lock(inode); I think we only need check the nowait here because we already check if the 'IOCB_DIRECT' flag and the 'IOCB_NOWAIT' flag are both set in the front of this function. > + if (direct_io && nowait) { > + if (!inode_trylock(inode)) > + return -EAGAIN; > + } else > + inode_lock(inode); > > /* > * Concurrent O_DIRECT writes are allowed with > @@ -2244,9 +2282,13 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, > */ > rw_level = (!direct_io || full_coherency || append_write); > > - ret = ocfs2_rw_lock(inode, rw_level); > + if (direct_io && nowait) > + ret = ocfs2_try_rw_lock(inode, rw_level); > + else > + ret = ocfs2_rw_lock(inode, rw_level); > if (ret < 0) { > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > goto out_mutex; > } > > @@ -2260,9 +2302,13 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, > * other nodes to drop their caches. Buffered I/O > * already does this in write_begin(). > */ > - ret = ocfs2_inode_lock(inode, NULL, 1); > + if (nowait) > + ret = ocfs2_try_inode_lock(inode, NULL, 1); > + else > + ret = ocfs2_inode_lock(inode, NULL, 1); > if (ret < 0) { > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > goto out; > } > > @@ -2277,9 +2323,10 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, > } > count = ret; > > - ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count); > + ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count, !nowait); > if (ret < 0) { > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > goto out; > } > > @@ -2355,6 +2402,7 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, > int ret = 0, rw_level = -1, lock_level = 0; > struct file *filp = iocb->ki_filp; > struct inode *inode = file_inode(filp); > + int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; > Here should we check if the 'IOCB_DIRECT' flag and the 'IOCB_NOWAIT' flag are both set? Thanks, Alex > trace_ocfs2_file_aio_read(inode, filp, filp->f_path.dentry, > (unsigned long long)OCFS2_I(inode)->ip_blkno, > @@ -2374,9 +2422,14 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, > * need locks to protect pending reads from racing with truncate. > */ > if (iocb->ki_flags & IOCB_DIRECT) { > - ret = ocfs2_rw_lock(inode, 0); > + if (nowait) > + ret = ocfs2_try_rw_lock(inode, 0); > + else > + ret = ocfs2_rw_lock(inode, 0); > + > if (ret < 0) { > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > goto bail; > } > rw_level = 0; > @@ -2393,9 +2446,11 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, > * like i_size. This allows the checks down below > * generic_file_aio_read() a chance of actually working. > */ > - ret = ocfs2_inode_lock_atime(inode, filp->f_path.mnt, &lock_level); > + ret = ocfs2_inode_lock_atime(inode, filp->f_path.mnt, &lock_level, > + !nowait); > if (ret < 0) { > - mlog_errno(ret); > + if (ret != -EAGAIN) > + mlog_errno(ret); > goto bail; > } > ocfs2_inode_unlock(inode, lock_level); > diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c > index 098f5c7..fb9a20e 100644 > --- a/fs/ocfs2/mmap.c > +++ b/fs/ocfs2/mmap.c > @@ -184,7 +184,7 @@ int ocfs2_mmap(struct file *file, struct vm_area_struct *vma) > int ret = 0, lock_level = 0; > > ret = ocfs2_inode_lock_atime(file_inode(file), > - file->f_path.mnt, &lock_level); > + file->f_path.mnt, &lock_level, 1); > if (ret < 0) { > mlog_errno(ret); > goto out; > diff --git a/fs/ocfs2/ocfs2_trace.h b/fs/ocfs2/ocfs2_trace.h > index a0b5d00..e2a11aa 100644 > --- a/fs/ocfs2/ocfs2_trace.h > +++ b/fs/ocfs2/ocfs2_trace.h > @@ -1449,20 +1449,22 @@ > > TRACE_EVENT(ocfs2_prepare_inode_for_write, > TP_PROTO(unsigned long long ino, unsigned long long saved_pos, > - unsigned long count), > - TP_ARGS(ino, saved_pos, count), > + unsigned long count, int wait), > + TP_ARGS(ino, saved_pos, count, wait), > TP_STRUCT__entry( > __field(unsigned long long, ino) > __field(unsigned long long, saved_pos) > __field(unsigned long, count) > + __field(int, wait) > ), > TP_fast_assign( > __entry->ino = ino; > __entry->saved_pos = saved_pos; > __entry->count = count; > + __entry->wait = wait; > ), > - TP_printk("%llu %llu %lu", __entry->ino, > - __entry->saved_pos, __entry->count) > + TP_printk("%llu %llu %lu %d", __entry->ino, > + __entry->saved_pos, __entry->count, __entry->wait) > ); > > DEFINE_OCFS2_INT_EVENT(generic_file_aio_read_ret); >