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| author | Luis Henriques <lhenriques@suse.de> | 2021-07-06 14:52:41 +0100 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2021-08-04 19:20:05 +0200 |
| commit | bf2ba432213fade50dd39f2e348085b758c0726e (patch) | |
| tree | 93d7a166a733d9a2cbac1e13eafb639aaaf02dd6 /fs/ceph/caps.c | |
| parent | c500bee1c5b2f1d59b1081ac879d73268ab0ff17 (diff) | |
| download | linux-bf2ba432213fade50dd39f2e348085b758c0726e.tar.gz linux-bf2ba432213fade50dd39f2e348085b758c0726e.tar.bz2 linux-bf2ba432213fade50dd39f2e348085b758c0726e.zip | |
ceph: reduce contention in ceph_check_delayed_caps()
Function ceph_check_delayed_caps() is called from the mdsc->delayed_work
workqueue and it can be kept looping for quite some time if caps keep
being added back to the mdsc->cap_delay_list. This may result in the
watchdog tainting the kernel with the softlockup flag.
This patch breaks this loop if the caps have been recently (i.e. during
the loop execution). Any new caps added to the list will be handled in
the next run.
Also, allow schedule_delayed() callers to explicitly set the delay value
instead of defaulting to 5s, so we can ensure that it runs soon
afterward if it looks like there is more work.
Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/46284
Signed-off-by: Luis Henriques <lhenriques@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph/caps.c')
| -rw-r--r-- | fs/ceph/caps.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 7bdefd0c789a..2a2900903f8c 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -4150,11 +4150,19 @@ bad: /* * Delayed work handler to process end of delayed cap release LRU list. + * + * If new caps are added to the list while processing it, these won't get + * processed in this run. In this case, the ci->i_hold_caps_max will be + * returned so that the work can be scheduled accordingly. */ -void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) +unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc) { struct inode *inode; struct ceph_inode_info *ci; + struct ceph_mount_options *opt = mdsc->fsc->mount_options; + unsigned long delay_max = opt->caps_wanted_delay_max * HZ; + unsigned long loop_start = jiffies; + unsigned long delay = 0; dout("check_delayed_caps\n"); spin_lock(&mdsc->cap_delay_lock); @@ -4162,6 +4170,11 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) ci = list_first_entry(&mdsc->cap_delay_list, struct ceph_inode_info, i_cap_delay_list); + if (time_before(loop_start, ci->i_hold_caps_max - delay_max)) { + dout("%s caps added recently. Exiting loop", __func__); + delay = ci->i_hold_caps_max; + break; + } if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 && time_before(jiffies, ci->i_hold_caps_max)) break; @@ -4177,6 +4190,8 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) } } spin_unlock(&mdsc->cap_delay_lock); + + return delay; } /* |