archive mirror
 help / color / mirror / Atom feed
From: "Aurélien Aptel" <>
To: Muhammad Usama Anjum <>,
	Steve French <>,
	Ronnie Sahlberg <>,
	open list <>
Subject: Re: [PATCH v2] cifs: remove unnecessary copies of tcon->crfid.fid
Date: Sat, 17 Apr 2021 12:53:37 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <20210415152409.GA2286719@LEGION>


This is better I think.

Muhammad Usama Anjum <> writes:
> @@ -894,6 +891,10 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
>  	/* BB TBD check to see if oplock level check can be removed below */
>  	if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) {
> +		/*
> +		 * caller expects this func to set the fid in crfid to valid
> +		 * cached root, so increment the refcount.
> +		 */

This comment is misleading. crfid variable doesn't exist anymore, and
the kref_get() here is because of this commit:

    commit 2f94a3125b87
    Author: Ronnie Sahlberg <>
    Date:   Thu Mar 28 11:20:02 2019 +1000
        cifs: fix kref underflow in close_shroot()

-->     This extra get() is only used to hold the structure until we get a lease
-->     break from the server at which point we will kref_put() it during lease
-->     processing.

When we queue a lease break, we usually get() the cifsFileInfo, but if
that cifsFileInfo is backed by a cached_fid, the cached_fid isn't
bumped. That commit was probably a work around for that.

@Ronnie :

struct cached_fid is starting to look very much like struct
cifsFileInfo. I wonder why we couldn't use it, along with
find_writable_file()/find_readable_file() to handle the caching.

Alternatively, make cifsFileInfo use cached_fid (perhaps renaming it in
the process, I don't know)

Because I suspect a lot more issues will come up regarding cached_fid
refcount and cifsFileInfo refcount going out of sync otherwise.

Aurélien Aptel / SUSE Labs Samba Team
GPG: 1839 CB5F 9F5B FB9B AA97  8C99 03C8 A49B 521B D5D3
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg, DE
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 247165 (AG München)

  reply	other threads:[~2021-04-17 10:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-15 15:24 [PATCH v2] cifs: remove unnecessary copies of tcon->crfid.fid Muhammad Usama Anjum
2021-04-17 10:53 ` Aurélien Aptel [this message]
2021-04-19 23:39   ` Steve French
2021-04-28 16:12     ` Muhammad Usama Anjum

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 \ \ \ \ \ \ \ \ \ \ \

* 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).