From: Andreas Gruenbacher <agruenba@redhat.com>
To: cluster-devel@redhat.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
NeilBrown <neilb@suse.com>, Thomas Graf <tgraf@suug.ch>,
Herbert Xu <herbert@gondor.apana.org.au>,
Tom Herbert <tom@quantonium.net>,
Andreas Gruenbacher <agruenba@redhat.com>
Subject: [PATCH v2 2/2] gfs2: Stop using rhashtable_walk_peek
Date: Thu, 29 Mar 2018 14:06:12 +0200 [thread overview]
Message-ID: <20180329120612.6104-3-agruenba@redhat.com> (raw)
In-Reply-To: <20180329120612.6104-1-agruenba@redhat.com>
Function rhashtable_walk_peek is problematic because there is no
guarantee that the glock previously returned still exists; when that key
is deleted, rhashtable_walk_peek can end up returning a different key,
which will cause an inconsistent glock dump. Fix this by keeping track
of the current glock in the seq file iterator functions instead.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/gfs2/glock.c | 47 ++++++++++++++++++++++++++++-------------------
1 file changed, 28 insertions(+), 19 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 82fb5583445c..097bd3c0f270 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1923,28 +1923,37 @@ void gfs2_glock_exit(void)
static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
{
- if (n == 0)
- gi->gl = rhashtable_walk_peek(&gi->hti);
- else {
- gi->gl = rhashtable_walk_next(&gi->hti);
- n--;
+ struct gfs2_glock *gl = gi->gl;
+
+ if (gl) {
+ if (n == 0)
+ return;
+ if (!lockref_put_not_zero(&gl->gl_lockref))
+ gfs2_glock_queue_put(gl);
}
for (;;) {
- if (IS_ERR_OR_NULL(gi->gl)) {
- if (!gi->gl)
- return;
- if (PTR_ERR(gi->gl) != -EAGAIN) {
- gi->gl = NULL;
- return;
+ gl = rhashtable_walk_next(&gi->hti);
+ if (IS_ERR_OR_NULL(gl)) {
+ if (gl == ERR_PTR(-EAGAIN)) {
+ n = 1;
+ continue;
}
- n = 0;
- } else if (gi->sdp == gi->gl->gl_name.ln_sbd &&
- !__lockref_is_dead(&gi->gl->gl_lockref)) {
- if (!n--)
- break;
+ gl = NULL;
+ break;
+ }
+ if (gl->gl_name.ln_sbd != gi->sdp)
+ continue;
+ if (n <= 1) {
+ if (!lockref_get_not_dead(&gl->gl_lockref))
+ continue;
+ break;
+ } else {
+ if (__lockref_is_dead(&gl->gl_lockref))
+ continue;
+ n--;
}
- gi->gl = rhashtable_walk_next(&gi->hti);
}
+ gi->gl = gl;
}
static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
@@ -1988,7 +1997,6 @@ static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
{
struct gfs2_glock_iter *gi = seq->private;
- gi->gl = NULL;
rhashtable_walk_stop(&gi->hti);
}
@@ -2076,7 +2084,8 @@ static int gfs2_glocks_release(struct inode *inode, struct file *file)
struct seq_file *seq = file->private_data;
struct gfs2_glock_iter *gi = seq->private;
- gi->gl = NULL;
+ if (gi->gl)
+ gfs2_glock_put(gi->gl);
rhashtable_walk_exit(&gi->hti);
return seq_release_private(inode, file);
}
--
2.14.3
next prev parent reply other threads:[~2018-03-29 12:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-29 12:06 [PATCH v2 0/2] gfs2: Stop using rhashtable_walk_peek Andreas Gruenbacher
2018-03-29 12:06 ` [PATCH v2 1/2] lockref: Add lockref_put_not_zero Andreas Gruenbacher
2018-03-29 12:06 ` Andreas Gruenbacher [this message]
2018-03-29 12:24 ` [Cluster-devel] [PATCH v2 0/2] gfs2: Stop using rhashtable_walk_peek Steven Whitehouse
2018-03-29 13:12 ` Andreas Gruenbacher
2018-03-29 12:35 ` Herbert Xu
2018-03-29 13:15 ` Andreas Gruenbacher
2018-03-29 15:41 ` Herbert Xu
2018-03-29 16:52 ` Andreas Gruenbacher
2018-03-29 17:06 ` Herbert Xu
2018-04-03 3:41 ` NeilBrown
2018-04-03 4:03 ` Herbert Xu
2018-04-04 15:46 ` [Cluster-devel] " Bob Peterson
2018-04-04 15:48 ` Herbert Xu
[not found] ` <CAHpGcMKxDNOkMMKB1_9H0ob-502cD89E-94a18prp91y_a52GA@mail.gmail.com>
2018-04-06 1:33 ` NeilBrown
2018-04-12 17:00 ` Bob Peterson
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=20180329120612.6104-3-agruenba@redhat.com \
--to=agruenba@redhat.com \
--cc=cluster-devel@redhat.com \
--cc=herbert@gondor.apana.org.au \
--cc=linux-kernel@vger.kernel.org \
--cc=neilb@suse.com \
--cc=netdev@vger.kernel.org \
--cc=tgraf@suug.ch \
--cc=tom@quantonium.net \
/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).