From: Filipe David Manana <fdmanana@gmail.com>
To: Robbie Ko <robbieko@synology.com>
Cc: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH 3/5] Btrfs: incremental send, fix orphan_dir_info not completely cleared
Date: Thu, 4 Jun 2015 17:24:54 +0100 [thread overview]
Message-ID: <CAL3q7H5Rj48S8BGT4xy+3pHhcwmNTAiEQB9ra3VLAOxfpcAeAw@mail.gmail.com> (raw)
In-Reply-To: <1433416690-19177-4-git-send-email-robbieko@synology.com>
On Thu, Jun 4, 2015 at 12:18 PM, Robbie Ko <robbieko@synology.com> wrote:
> There's one case where we not clear orphan_dir_info issue.
You mean where we leak a orphan_dir_info structure.
>
> Example:
>
> Parent snapshot:
> |---- a/ (ino 279)
> |---- c (ino 282)
> |---- del/ (ino 281)
> |---- tmp/ (ino 280)
> |---- long/ (ino 283)
> |---- longlong/ (ino 284)
>
> Send snapshot:
> |---- a/ (ino 279)
> |---- long (ino 283)
> |---- longlong (ino 284)
> |---- c/ (ino 282)
> |---- tmp/ (ino 280)
>
> Here we process 281 use can_rmdir check, but 280 is waiting, so create orphan_dir_info
> and when 282 is move to dest, so 280 can move to c/tmp, and now run can_rmdir check again.
> Return is false, because 283 and 284 is unprocess, but now not release orphan_dir_info.
> When 283 and 284 is processd, 281 be delete, but not delete orphan_dir_info.
> So fix this by release orphan_dir_info for this case.
Could be described more generically as freeing an existing
orphan_dir_info for a directory, when we realize we can't rmdir the
directory because it has a descendant that wasn't yet processed, and
the orphan_dir_info was created because it had a descendant that had
its rename operation delayed.
>
> Signed-off-by: Robbie Ko <robbieko@synology.com>
> ---
> fs/btrfs/send.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index 596b9dc..ff9d052 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -2785,12 +2785,6 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino)
> struct rb_node *parent = NULL;
> struct orphan_dir_info *entry, *odi;
>
> - odi = kmalloc(sizeof(*odi), GFP_NOFS);
> - if (!odi)
> - return ERR_PTR(-ENOMEM);
> - odi->ino = dir_ino;
> - odi->gen = 0;
> -
> while (*p) {
> parent = *p;
> entry = rb_entry(parent, struct orphan_dir_info, node);
> @@ -2799,11 +2793,16 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino)
> } else if (dir_ino > entry->ino) {
> p = &(*p)->rb_right;
> } else {
> - kfree(odi);
> return entry;
> }
> }
>
> + odi = kmalloc(sizeof(*odi), GFP_NOFS);
> + if (!odi)
> + return ERR_PTR(-ENOMEM);
> + odi->ino = dir_ino;
> + odi->gen = 0;
> +
All the above changes don't fix the issue described in this change -
the memory leak - they just avoid the overhead of allocating an
orphan_dir_info object unnecessarily.
The change is ok, but should be a separate patch in the series that
does only that.
> rb_link_node(&odi->node, parent, p);
> rb_insert_color(&odi->node, &sctx->orphan_dirs);
> return odi;
> @@ -2913,6 +2912,12 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen,
> }
>
> if (loc.objectid > send_progress) {
> + struct orphan_dir_info *odi;
> +
> + odi = get_orphan_dir_info(sctx, dir);
> + if (odi) {
> + free_orphan_dir_info(sctx, odi);
> + }
Looks correct, great catch.
Thanks.
> ret = 0;
> goto out;
> }
> --
> 1.9.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Filipe David Manana,
"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."
next prev parent reply other threads:[~2015-06-04 16:24 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-04 11:18 [PATCH 0/5] Btrfs incremental send fix serval case for rename and rm directory Robbie Ko
2015-06-04 11:18 ` [PATCH 1/5] Btrfs: incremental send, avoid circular waiting and descendant overwrite ancestor need to update path Robbie Ko
2015-06-04 13:50 ` Filipe David Manana
2015-06-04 19:19 ` Filipe David Manana
2015-06-05 3:55 ` Robbie Ko
2015-06-05 8:46 ` Filipe David Manana
2015-06-04 11:18 ` [PATCH 2/5] Btrfs: incremental send, avoid ancestor rename to descendant Robbie Ko
2015-06-04 15:43 ` Filipe David Manana
2015-06-05 11:18 ` Robbie Ko
2015-06-04 11:18 ` [PATCH 3/5] Btrfs: incremental send, fix orphan_dir_info not completely cleared Robbie Ko
2015-06-04 16:24 ` Filipe David Manana [this message]
2015-06-05 13:58 ` David Sterba
2015-06-04 11:18 ` [PATCH 4/5] Btrfs: incremental send, fix rmdir but dir have a unprocess item Robbie Ko
2015-06-04 16:40 ` Filipe David Manana
2015-06-04 11:18 ` [PATCH 5/5] Btrfs: incremental send, fix rmdir not send utimes Robbie Ko
2015-06-04 16:14 ` Filipe David Manana
2015-06-08 3:44 ` Robbie Ko
2015-06-08 14:00 ` Filipe David Manana
2015-06-09 10:04 ` Robbie Ko
2015-06-09 10:36 ` Filipe David Manana
2015-06-10 10:06 ` Robbie Ko
2015-06-18 3:21 ` Robbie Ko
2015-06-18 18:11 ` Filipe David Manana
2015-06-22 5:35 ` Robbie Ko
2015-06-04 13:04 ` [PATCH 0/5] Btrfs incremental send fix serval case for rename and rm directory Filipe David Manana
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=CAL3q7H5Rj48S8BGT4xy+3pHhcwmNTAiEQB9ra3VLAOxfpcAeAw@mail.gmail.com \
--to=fdmanana@gmail.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=robbieko@synology.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.