linux/fs/afs
David Howells c410bf0193 rxrpc: Fix the excessive initial retransmission timeout
rxrpc currently uses a fixed 4s retransmission timeout until the RTT is
sufficiently sampled.  This can cause problems with some fileservers with
calls to the cache manager in the afs filesystem being dropped from the
fileserver because a packet goes missing and the retransmission timeout is
greater than the call expiry timeout.

Fix this by:

 (1) Copying the RTT/RTO calculation code from Linux's TCP implementation
     and altering it to fit rxrpc.

 (2) Altering the various users of the RTT to make use of the new SRTT
     value.

 (3) Replacing the use of rxrpc_resend_timeout to use the calculated RTO
     value instead (which is needed in jiffies), along with a backoff.

Notes:

 (1) rxrpc provides RTT samples by matching the serial numbers on outgoing
     DATA packets that have the RXRPC_REQUEST_ACK set and PING ACK packets
     against the reference serial number in incoming REQUESTED ACK and
     PING-RESPONSE ACK packets.

 (2) Each packet that is transmitted on an rxrpc connection gets a new
     per-connection serial number, even for retransmissions, so an ACK can
     be cross-referenced to a specific trigger packet.  This allows RTT
     information to be drawn from retransmitted DATA packets also.

 (3) rxrpc maintains the RTT/RTO state on the rxrpc_peer record rather than
     on an rxrpc_call because many RPC calls won't live long enough to
     generate more than one sample.

 (4) The calculated SRTT value is in units of 8ths of a microsecond rather
     than nanoseconds.

The (S)RTT and RTO values are displayed in /proc/net/rxrpc/peers.

Fixes: 17926a7932 ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-11 16:42:28 +01:00
..
addr_list.c afs: Use kfree_rcu() instead of casting kfree() to rcu_callback_t 2020-03-13 10:47:33 -07:00
afs_cm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
afs_fs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
afs_vl.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
afs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cache.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
callback.c afs: Fix possible assert with callbacks from yfs servers 2019-11-22 14:19:26 -08:00
cell.c afs: Fix characters allowed into cell names 2020-01-26 08:54:04 -08:00
cmservice.c afs: Fix to actually set AFS_SERVER_FL_HAVE_EPOCH 2020-04-24 16:32:49 +01:00
dir_edit.c afs: Remove set but not used variables 'before', 'after' 2019-11-21 20:36:00 +00:00
dir_silly.c afs: Fix race between post-modification dir edit and readdir/d_revalidate 2020-04-13 15:09:01 +01:00
dir.c afs: Fix afs_d_validate() to set the right directory version 2020-04-13 15:09:01 +01:00
dynroot.c afs: Fix creation calls in the dynamic root to fail with EOPNOTSUPP 2019-12-11 17:47:51 +00:00
file.c afs: Rename desc -> req in afs_fetch_data() 2019-11-21 09:12:17 +00:00
flock.c fs: afs: Use pr_warn instead of pr_warning 2019-10-18 15:01:55 +02:00
fs_probe.c rxrpc: Fix the excessive initial retransmission timeout 2020-05-11 16:42:28 +01:00
fsclient.c afs: Fix rename operation status delivery 2020-04-13 15:09:01 +01:00
inode.c Printk changes for 5.5 2019-11-25 19:40:40 -08:00
internal.h afs: Make record checking use TASK_UNINTERRUPTIBLE when appropriate 2020-04-24 16:33:32 +01:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
main.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
Makefile afs: do not send list of client addresses 2019-06-02 18:06:26 -07:00
misc.c AFS development 2019-07-10 20:55:33 -07:00
mntpt.c afs: Fix mountpoint parsing 2019-12-11 16:56:54 +00:00
proc.c afs: Show volume name in /proc/net/afs/<cell>/volumes 2019-12-11 17:48:20 +00:00
protocol_uae.h afs: Add support for the UAE error table 2019-06-28 18:37:53 +01:00
protocol_yfs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
rotate.c afs: Make record checking use TASK_UNINTERRUPTIBLE when appropriate 2020-04-24 16:33:32 +01:00
rxrpc.c afs: Fix client call Rx-phase signal handling 2020-03-13 23:04:35 +00:00
security.c afs: Support RCU pathwalk 2019-09-02 11:43:54 +01:00
server_list.c AFS development 2019-07-10 20:55:33 -07:00
server.c afs: Make record checking use TASK_UNINTERRUPTIBLE when appropriate 2020-04-24 16:33:32 +01:00
super.c fs_parse: fold fs_parameter_desc/fs_parameter_spec 2020-02-07 14:48:37 -05:00
vl_list.c fs/afs: Replace rcu_swap_protected() with rcu_replace_pointer() 2019-10-30 08:44:27 -07:00
vl_probe.c rxrpc: Fix the excessive initial retransmission timeout 2020-05-11 16:42:28 +01:00
vl_rotate.c afs: Remove some unused bits 2020-04-24 16:32:49 +01:00
vlclient.c afs: Switch the naming of call->iter and call->_iter 2019-11-21 09:12:17 +00:00
volume.c afs: Make record checking use TASK_UNINTERRUPTIBLE when appropriate 2020-04-24 16:33:32 +01:00
write.c AFS development 2019-07-10 20:55:33 -07:00
xattr.c afs: xattr: use scnprintf 2019-11-21 09:12:17 +00:00
xdr_fs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
yfsclient.c afs: Fix length of dump of bad YFSFetchStatus record 2020-04-13 15:09:01 +01:00