($INBOX_DIR/description missing)
 help / color / Atom feed
From: Amir Goldstein <amir73il@gmail.com>
To: Chengguang Xu <cgxu519@mykernel.net>, Miklos Szeredi <miklos@szeredi.hu>
Cc: overlayfs <linux-unionfs@vger.kernel.org>
Subject: Re: [PATCH] ovl: fix incorrect extent info in metacopy case
Date: Thu, 25 Jun 2020 11:35:17 +0300
Message-ID: <CAOQ4uxh9gzdRJp4g1yjQy9nDMASdsdvkzBGhGL2_+3rOBJZFAw@mail.gmail.com> (raw)
In-Reply-To: <CAOQ4uxi53CzBwXxygKMhDDSaGpX0CcfV6jiaKRFVbrFHW7PbxA@mail.gmail.com>

On Wed, Jun 24, 2020 at 3:53 PM Amir Goldstein <amir73il@gmail.com> wrote:
> On Wed, Jun 24, 2020 at 1:23 PM Chengguang Xu <cgxu519@mykernel.net> wrote:
> >
> > In metacopy case, we should use ovl_inode_realdata() instead of
> > ovl_inode_real() to get real inode which has data, so that
> > we can get correct information of extentes in ->fiemap operation.
> >
> > Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
> looks right


Not related to this patch, I noticed something that could be odd with

When passed the flag FIEMAP_FLAG_SYNC, ->fiemap() will trigger writeback
of lower inode pages.

This behavior is border line for overlayfs.
I did not check if filemap_write_and_wait() ends up being a noop on read-only
fs or if it can return an error.
Following ovl_fsync() practice, we may want to silently drop the
FIEMAP_FLAG_SYNC flag? but that could result in unexpected results.

Am I overthinking this?


  reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-24 10:20 Chengguang Xu
2020-06-24 12:53 ` Amir Goldstein
2020-06-25  8:35   ` Amir Goldstein [this message]
2020-06-25  9:46     ` cgxu

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:

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

  git send-email \
    --in-reply-to=CAOQ4uxh9gzdRJp4g1yjQy9nDMASdsdvkzBGhGL2_+3rOBJZFAw@mail.gmail.com \
    --to=amir73il@gmail.com \
    --cc=cgxu519@mykernel.net \
    --cc=linux-unionfs@vger.kernel.org \
    --cc=miklos@szeredi.hu \


* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

($INBOX_DIR/description missing)

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-unionfs/0 linux-unionfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-unionfs linux-unionfs/ https://lore.kernel.org/linux-unionfs \
	public-inbox-index linux-unionfs

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone https://public-inbox.org/public-inbox.git