From: Andreas Gruenbacher <agruenba@redhat.com>
To: gfs2@lists.linux.dev
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Subject: [PATCH 13/15] gfs2: Fix "Make glock lru list scanning safer"
Date: Tue, 9 Apr 2024 18:45:03 +0200 [thread overview]
Message-ID: <20240409164508.79570-14-agruenba@redhat.com> (raw)
In-Reply-To: <20240409164508.79570-1-agruenba@redhat.com>
Commit 228804a35caa tried to add a refcount check to
gfs2_scan_glock_lru() to make sure that glocks that are still referenced
cannot be freed. It failed to account for the bias state_change() adds
to the refcount for held glocks, so held glocks are no longer removed
from the glock cache, which can lead to out-of-memory problems. Fix
that. (The inodes those glocks are associated with do get shrunk and do
get pushed out of memory.)
In addition, use the same eligibility check in gfs2_scan_glock_lru() and
gfs2_dispose_glock_lru().
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/gfs2/glock.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 2882a42e88aa..04e0a8ac61d7 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1987,6 +1987,14 @@ static int glock_cmp(void *priv, const struct list_head *a,
return 0;
}
+static bool can_free_glock(struct gfs2_glock *gl)
+{
+ bool held = gl->gl_state != LM_ST_UNLOCKED;
+
+ return !test_bit(GLF_LOCK, &gl->gl_flags) &&
+ gl->gl_lockref.count == held;
+}
+
/**
* gfs2_dispose_glock_lru - Demote a list of glocks
* @list: The list to dispose of
@@ -2020,7 +2028,7 @@ __acquires(&lru_lock)
atomic_inc(&lru_count);
continue;
}
- if (test_bit(GLF_LOCK, &gl->gl_flags)) {
+ if (!can_free_glock(gl)) {
spin_unlock(&gl->gl_lockref.lock);
goto add_back_to_lru;
}
@@ -2052,16 +2060,10 @@ static long gfs2_scan_glock_lru(int nr)
list_for_each_entry_safe(gl, next, &lru_list, gl_lru) {
if (nr-- <= 0)
break;
- /* Test for being demotable */
- if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
- if (!spin_trylock(&gl->gl_lockref.lock))
- continue;
- if (!gl->gl_lockref.count) {
- list_move(&gl->gl_lru, &dispose);
- atomic_dec(&lru_count);
- freed++;
- }
- spin_unlock(&gl->gl_lockref.lock);
+ if (can_free_glock(gl)) {
+ list_move(&gl->gl_lru, &dispose);
+ atomic_dec(&lru_count);
+ freed++;
}
}
if (!list_empty(&dispose))
--
2.44.0
next prev parent reply other threads:[~2024-04-09 16:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-09 16:44 [PATCH 00/15] gfs2 cleanups and fixes Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 01/15] gfs2: Get rid of newlines in log messages Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 02/15] gfs2: Remove unnecessary gfs2_meta_check_ii argument Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 03/15] gfs2: Follow-up to flag rename in sysfs status file Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 04/15] gfs2: Use [NO_]CREATE consistently for gfs2_glock_get Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 05/15] gfs2: Don't forget to complete delayed withdraw Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 06/15] gfs2: Fix NULL pointer dereference in gfs2_log_flush Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 07/15] gfs2: Get rid of gfs2_glock_queue_put in signal_our_withdraw Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 08/15] gfs2: Replace gfs2_glock_queue_put with gfs2_glock_put_async Andreas Gruenbacher
2024-04-09 16:44 ` [PATCH 09/15] gfs2: Don't set GLF_LOCK in gfs2_dispose_glock_lru Andreas Gruenbacher
2024-04-09 16:45 ` [PATCH 10/15] gfs2: Get rid of unnecessary test_and_set_bit Andreas Gruenbacher
2024-04-09 16:45 ` [PATCH 11/15] gfs2: Fix "ignore unlock failures after withdraw" Andreas Gruenbacher
2024-04-09 16:45 ` [PATCH 12/15] Revert "gfs2: fix glock shrinker ref issues" Andreas Gruenbacher
2024-04-09 16:45 ` Andreas Gruenbacher [this message]
2024-04-16 16:55 ` [PATCH 13/15] gfs2: Fix "Make glock lru list scanning safer" Andrew Price
2024-04-17 7:55 ` Andreas Gruenbacher
2024-04-09 16:45 ` [PATCH 14/15] gfs2: Get rid of demote_ok checks Andreas Gruenbacher
2024-04-12 6:00 ` Andreas Gruenbacher
2024-04-09 16:45 ` [PATCH 15/15] gfs2: Fix lru_count accounting Andreas Gruenbacher
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