From: Luis Henriques lhenriques@suse.de
stable inclusion from stable-5.10.60 commit f3fcf9d1b759915dcc1a93bceada910287c54e76 bugzilla: 177018 https://gitee.com/openeuler/kernel/issues/I4EAUG
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit bf2ba432213fade50dd39f2e348085b758c0726e upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- fs/ceph/caps.c | 17 ++++++++++++++++- fs/ceph/mds_client.c | 25 ++++++++++++++++--------- fs/ceph/super.h | 2 +- 3 files changed, 33 insertions(+), 11 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index e4fc99afa25a..45093a765a9b 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -4202,11 +4202,19 @@ void ceph_handle_caps(struct ceph_mds_session *session,
/* * 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); @@ -4214,6 +4222,11 @@ 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; @@ -4230,6 +4243,8 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) } } spin_unlock(&mdsc->cap_delay_lock); + + return delay; }
/* diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 6b00f1d7c8e7..1701902415c4 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -4435,22 +4435,29 @@ void inc_session_sequence(struct ceph_mds_session *s) }
/* - * delayed work -- periodically trim expired leases, renew caps with mds + * delayed work -- periodically trim expired leases, renew caps with mds. If + * the @delay parameter is set to 0 or if it's more than 5 secs, the default + * workqueue delay value of 5 secs will be used. */ -static void schedule_delayed(struct ceph_mds_client *mdsc) +static void schedule_delayed(struct ceph_mds_client *mdsc, unsigned long delay) { - int delay = 5; - unsigned hz = round_jiffies_relative(HZ * delay); - schedule_delayed_work(&mdsc->delayed_work, hz); + unsigned long max_delay = HZ * 5; + + /* 5 secs default delay */ + if (!delay || (delay > max_delay)) + delay = max_delay; + schedule_delayed_work(&mdsc->delayed_work, + round_jiffies_relative(delay)); }
static void delayed_work(struct work_struct *work) { - int i; struct ceph_mds_client *mdsc = container_of(work, struct ceph_mds_client, delayed_work.work); + unsigned long delay; int renew_interval; int renew_caps; + int i;
dout("mdsc delayed_work\n");
@@ -4490,7 +4497,7 @@ static void delayed_work(struct work_struct *work) } mutex_unlock(&mdsc->mutex);
- ceph_check_delayed_caps(mdsc); + delay = ceph_check_delayed_caps(mdsc);
ceph_queue_cap_reclaim_work(mdsc);
@@ -4498,7 +4505,7 @@ static void delayed_work(struct work_struct *work)
maybe_recover_session(mdsc);
- schedule_delayed(mdsc); + schedule_delayed(mdsc, delay); }
int ceph_mdsc_init(struct ceph_fs_client *fsc) @@ -4984,7 +4991,7 @@ void ceph_mdsc_handle_mdsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg) mdsc->mdsmap->m_epoch);
mutex_unlock(&mdsc->mutex); - schedule_delayed(mdsc); + schedule_delayed(mdsc, 0); return;
bad_unlock: diff --git a/fs/ceph/super.h b/fs/ceph/super.h index c33f744a8e11..6712509ae1d6 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -1138,7 +1138,7 @@ extern void ceph_flush_snaps(struct ceph_inode_info *ci, extern bool __ceph_should_report_size(struct ceph_inode_info *ci); extern void ceph_check_caps(struct ceph_inode_info *ci, int flags, struct ceph_mds_session *session); -extern void ceph_check_delayed_caps(struct ceph_mds_client *mdsc); +extern unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc); extern void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc); extern int ceph_drop_caps_for_unlink(struct inode *inode); extern int ceph_encode_inode_release(void **p, struct inode *inode,