linux-unionfs.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Chengguang Xu <cgxu519@mykernel.net>
To: "Jan Kara" <jack@suse.cz>
Cc: "miklos" <miklos@szeredi.hu>, "amir73il" <amir73il@gmail.com>,
	"linux-unionfs" <linux-unionfs@vger.kernel.org>,
	"linux-fsdevel" <linux-fsdevel@vger.kernel.org>,
	"cgxu519" <cgxu519@mykernel.net>,
	"charliecgxu" <charliecgxu@tencent.com>
Subject: Re: [RFC PATCH v2 2/8] ovl: implement ->writepages operation
Date: Wed, 04 Nov 2020 20:18:16 +0800	[thread overview]
Message-ID: <175933181cc.ed06c3957114.1028981429730337490@mykernel.net> (raw)
In-Reply-To: <20201102171741.GE23988@quack2.suse.cz>

 ---- 在 星期二, 2020-11-03 01:17:41 Jan Kara <jack@suse.cz> 撰写 ----
 > On Sun 25-10-20 11:41:11, Chengguang Xu wrote:
 > > Implement overlayfs' ->writepages operation so that
 > > we can sync dirty data/metadata to upper filesystem.
 > > 
 > > Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
 > > ---
 > >  fs/overlayfs/inode.c | 26 ++++++++++++++++++++++++++
 > >  1 file changed, 26 insertions(+)
 > > 
 > > diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
 > > index b584dca845ba..f27fc5be34df 100644
 > > --- a/fs/overlayfs/inode.c
 > > +++ b/fs/overlayfs/inode.c
 > > @@ -11,6 +11,7 @@
 > >  #include <linux/posix_acl.h>
 > >  #include <linux/ratelimit.h>
 > >  #include <linux/fiemap.h>
 > > +#include <linux/writeback.h>
 > >  #include "overlayfs.h"
 > >  
 > >  
 > > @@ -516,7 +517,32 @@ static const struct inode_operations ovl_special_inode_operations = {
 > >      .update_time    = ovl_update_time,
 > >  };
 > >  
 > > +static int ovl_writepages(struct address_space *mapping,
 > > +              struct writeback_control *wbc)
 > > +{
 > > +    struct inode *upper_inode = ovl_inode_upper(mapping->host);
 > > +    struct ovl_fs *ofs =  mapping->host->i_sb->s_fs_info;
 > > +    struct writeback_control tmp_wbc = *wbc;
 > > +
 > > +    if (!ovl_should_sync(ofs))
 > > +        return 0;
 > > +
 > > +    /*
 > > +     * for sync(2) writeback, it has a separate external IO
 > > +     * completion path by checking PAGECACHE_TAG_WRITEBACK
 > > +     * in pagecache, we have to set for_sync to 0 in thie case,
 > > +     * let writeback waits completion after syncing individual
 > > +     * dirty inode, because we haven't implemented overlayfs'
 > > +     * own pagecache yet.
 > > +     */
 > > +    if (wbc->for_sync && (wbc->sync_mode == WB_SYNC_ALL))
 > > +        tmp_wbc.for_sync = 0;
 > 
 > This looks really hacky as it closely depends on the internal details of
 > writeback implementation. I'd be more open to say export wait_sb_inodes()
 > for overlayfs use... Because that's what I gather you need in your
 > overlayfs ->syncfs() implementation.
 > 

Does  that mean we gather synced overlay's inode into a new waiting list(overlay's) and
do the waiting behavior in overlay's ->syncfs() ?


Thanks,
Chengguang



  reply	other threads:[~2020-11-04 12:18 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-25  3:41 [RFC PATCH v2 0/8] implement containerized syncfs for overlayfs Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 1/8] ovl: setup overlayfs' private bdi Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 2/8] ovl: implement ->writepages operation Chengguang Xu
2020-11-02 17:17   ` Jan Kara
2020-11-04 12:18     ` Chengguang Xu [this message]
2020-11-05 13:55       ` Jan Kara
2020-11-06  5:57         ` Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 3/8] ovl: implement overlayfs' ->evict_inode operation Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 4/8] ovl: mark overlayfs' inode dirty on modification Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 5/8] ovl: mark overlayfs' inode dirty on shared writable mmap Chengguang Xu
2020-11-02 17:30   ` Jan Kara
2020-11-04 11:54     ` Chengguang Xu
2020-11-05 14:03       ` Jan Kara
2020-11-05 14:21         ` Amir Goldstein
2020-11-05 15:54           ` Jan Kara
2020-11-06  2:41             ` Chengguang Xu
2020-11-06  8:50               ` Jan Kara
2020-11-06  9:47                 ` Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 6/8] ovl: implement overlayfs' ->write_inode operation Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 7/8] ovl: cache dirty overlayfs' inode Chengguang Xu
2020-10-25  3:41 ` [RFC PATCH v2 8/8] ovl: implement containerized syncfs for overlayfs Chengguang Xu
2020-10-30 15:46 ` [RFC PATCH v2 0/8] " Miklos Szeredi
2020-10-31 12:22   ` Chengguang Xu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=175933181cc.ed06c3957114.1028981429730337490@mykernel.net \
    --to=cgxu519@mykernel.net \
    --cc=amir73il@gmail.com \
    --cc=charliecgxu@tencent.com \
    --cc=jack@suse.cz \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-unionfs@vger.kernel.org \
    --cc=miklos@szeredi.hu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).