This is a note to let you know that I've just added the patch titled
ceph: show tasks waiting on caps in debugfs caps file
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ceph-show-tasks-waiting-on-caps-in-debugfs-caps-file.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fd9e7abd7fa46fb25a2e67db89382ade84965de1
Author: Jeff Layton <jlayton@xxxxxxxxxx>
Date: Wed Nov 20 12:00:59 2019 -0500
ceph: show tasks waiting on caps in debugfs caps file
[ Upstream commit 3a3430affce5de301fc8e6e50fa3543d7597820e ]
Add some visibility of tasks that are waiting for caps to the "caps"
debugfs file. Display the tgid of the waiting task, inode number, and
the caps the task needs and wants.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Reviewed-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Stable-dep-of: e7e607bd0048 ("ceph: defer stopping mdsc delayed_work")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 243e246cb5046..4e88cb9907230 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2790,7 +2790,19 @@ int ceph_get_caps(struct file *filp, int need, int want,
if (ret == -EAGAIN)
continue;
if (!ret) {
+ struct ceph_mds_client *mdsc = fsc->mdsc;
+ struct cap_wait cw;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
+
+ cw.ino = inode->i_ino;
+ cw.tgid = current->tgid;
+ cw.need = need;
+ cw.want = want;
+
+ spin_lock(&mdsc->caps_list_lock);
+ list_add(&cw.list, &mdsc->cap_wait_list);
+ spin_unlock(&mdsc->caps_list_lock);
+
add_wait_queue(&ci->i_cap_wq, &wait);
flags |= NON_BLOCKING;
@@ -2804,6 +2816,11 @@ int ceph_get_caps(struct file *filp, int need, int want,
}
remove_wait_queue(&ci->i_cap_wq, &wait);
+
+ spin_lock(&mdsc->caps_list_lock);
+ list_del(&cw.list);
+ spin_unlock(&mdsc->caps_list_lock);
+
if (ret == -EAGAIN)
continue;
}
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index facb387c27356..c281f32b54f7b 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -139,6 +139,7 @@ static int caps_show(struct seq_file *s, void *p)
struct ceph_fs_client *fsc = s->private;
struct ceph_mds_client *mdsc = fsc->mdsc;
int total, avail, used, reserved, min, i;
+ struct cap_wait *cw;
ceph_reservation_status(fsc, &total, &avail, &used, &reserved, &min);
seq_printf(s, "total\t\t%d\n"
@@ -166,6 +167,18 @@ static int caps_show(struct seq_file *s, void *p)
}
mutex_unlock(&mdsc->mutex);
+ seq_printf(s, "\n\nWaiters:\n--------\n");
+ seq_printf(s, "tgid ino need want\n");
+ seq_printf(s, "-----------------------------------------------------\n");
+
+ spin_lock(&mdsc->caps_list_lock);
+ list_for_each_entry(cw, &mdsc->cap_wait_list, list) {
+ seq_printf(s, "%-13d0x%-17lx%-17s%-17s\n", cw->tgid, cw->ino,
+ ceph_cap_string(cw->need),
+ ceph_cap_string(cw->want));
+ }
+ spin_unlock(&mdsc->caps_list_lock);
+
return 0;
}
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 3bf81fe5f10a3..6ceda2a4791c4 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4174,6 +4174,7 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
mdsc->last_renew_caps = jiffies;
INIT_LIST_HEAD(&mdsc->cap_delay_list);
+ INIT_LIST_HEAD(&mdsc->cap_wait_list);
spin_lock_init(&mdsc->cap_delay_lock);
INIT_LIST_HEAD(&mdsc->snap_flush_list);
spin_lock_init(&mdsc->snap_flush_lock);
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 5cd131b41d84f..14c7e8c49970a 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -340,6 +340,14 @@ struct ceph_quotarealm_inode {
struct inode *inode;
};
+struct cap_wait {
+ struct list_head list;
+ unsigned long ino;
+ pid_t tgid;
+ int need;
+ int want;
+};
+
/*
* mds client state
*/
@@ -416,6 +424,7 @@ struct ceph_mds_client {
spinlock_t caps_list_lock;
struct list_head caps_list; /* unused (reserved or
unreserved) */
+ struct list_head cap_wait_list;
int caps_total_count; /* total caps allocated */
int caps_use_count; /* in use */
int caps_use_max; /* max used caps */
