[PATCH v1 06/13] ceph: set default timeout for MDS requests

[Ionut Nechita (Wind River)]

From: Ionut Nechita <ionut.nechita@xxxxxxxxxxxxx>

MDS requests created via ceph_mdsc_create_request() have r_timeout
initialized to 0 (from kmem_cache_zalloc). When r_timeout is 0,
ceph_timeout_jiffies() returns MAX_SCHEDULE_TIMEOUT, causing
ceph_mdsc_wait_request() to wait indefinitely.

This causes hung task warnings when MDS becomes unavailable during
operations like setattr or truncate:

  INFO: task dd:12345 blocked for more than 122 seconds.
  Call Trace:
    ceph_mdsc_wait_request+0x...
    ceph_mdsc_do_request+0x...
    __ceph_setattr+0x...

Only the mount path in super.c explicitly sets r_timeout to
mount_timeout. All other MDS requests (setattr, lookup, mkdir,
etc.) use the default 0 value, making them wait forever.

Fix this by initializing r_timeout to mount_timeout in
ceph_mdsc_create_request(). This ensures all MDS requests have
a reasonable timeout and will fail with -ETIMEDOUT rather than
hanging indefinitely.

Signed-off-by: Ionut Nechita <ionut.nechita@xxxxxxxxxxxxx>
---
 fs/ceph/mds_client.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 45abddd7f317e..ac86225595b5f 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2613,6 +2613,7 @@ ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
 	mutex_init(&req->r_fill_mutex);
 	req->r_mdsc = mdsc;
 	req->r_started = jiffies;
+	req->r_timeout = mdsc->fsc->client->options->mount_timeout;
 	req->r_start_latency = ktime_get();
 	req->r_resend_mds = -1;
 	INIT_LIST_HEAD(&req->r_unsafe_dir_item);
-- 
2.53.0