BMC/Intel-BMC/linux.git/net/ceph/messenger.c, branch dev-4.4

libceph: use the right footer size when skipping a message

2016-03-03T23:07:26+00:00

commit dbc0d3caff5b7591e0cf8e34ca686ca6f4479ee1 upstream. ceph_msg_footer is 21 bytes long, while ceph_msg_footer_old is only 13. Don't skip too much when CEPH_FEATURE_MSG_AUTH isn't negotiated. Signed-off-by: Ilya Dryomov Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman

libceph: don't bail early from try_read() when skipping a message

2016-03-03T23:07:26+00:00

commit e7a88e82fe380459b864e05b372638aeacb0f52d upstream. The contract between try_read() and try_write() is that when called each processes as much data as possible. When instructed by osd_client to skip a message, try_read() is violating this contract by returning after receiving and discarding a single message instead of checking for more. try_write() then gets a chance to write out more requests, generating more replies/skips for try_read() to handle, forcing the messenger into a starvation loop. Reported-by: Varada Kari Signed-off-by: Ilya Dryomov Tested-by: Varada Kari Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman

libceph: fix ceph_msg_revoke()

2016-03-03T23:07:26+00:00

commit 67645d7619738e51c668ca69f097cb90b5470422 upstream. There are a number of problems with revoking a "was sending" message: (1) We never make any attempt to revoke data - only kvecs contibute to con->out_skip. However, once the header (envelope) is written to the socket, our peer learns data_len and sets itself to expect at least data_len bytes to follow front or front+middle. If ceph_msg_revoke() is called while the messenger is sending message's data portion, anything we send after that call is counted by the OSD towards the now revoked message's data portion. The effects vary, the most common one is the eventual hang - higher layers get stuck waiting for the reply to the message that was sent out after ceph_msg_revoke() returned and treated by the OSD as a bunch of data bytes. This is what Matt ran into. (2) Flat out zeroing con->out_kvec_bytes worth of bytes to handle kvecs is wrong. If ceph_msg_revoke() is called before the tag is sent out or while the messenger is sending the header, we will get a connection reset, either due to a bad tag (0 is not a valid tag) or a bad header CRC, which kind of defeats the purpose of revoke. Currently the kernel client refuses to work with header CRCs disabled, but that will likely change in the future, making this even worse. (3) con->out_skip is not reset on connection reset, leading to one or more spurious connection resets if we happen to get a real one between con->out_skip is set in ceph_msg_revoke() and before it's cleared in write_partial_skip(). Fixing (1) and (3) is trivial. The idea behind fixing (2) is to never zero the tag or the header, i.e. send out tag+header regardless of when ceph_msg_revoke() is called. That way the header is always correct, no unnecessary resets are induced and revoke stands ready for disabled CRCs. Since ceph_msg_revoke() rips out con->out_msg, introduce a new "message out temp" and copy the header into it before sending. Reported-by: Matt Conner Signed-off-by: Ilya Dryomov Tested-by: Matt Conner Reviewed-by: Sage Weil Signed-off-by: Greg Kroah-Hartman

libceph: clear msg->con in ceph_msg_release() only

2015-11-02T22:37:46+00:00

The following bit in ceph_msg_revoke_incoming() is unsafe: struct ceph_connection *con = msg->con; if (!con) return; mutex_lock(&con->mutex); con use> There is nothing preventing con from getting destroyed right after msg->con test. One easy way to reproduce this is to disable message signing only on the server side and try to map an image. The system will go into a libceph: read_partial_message ffff880073f0ab68 signature check failed libceph: osd0 192.168.255.155:6801 bad crc/signature libceph: read_partial_message ffff880073f0ab68 signature check failed libceph: osd0 192.168.255.155:6801 bad crc/signature loop which has to be interrupted with Ctrl-C. Hit Ctrl-C and you are likely to end up with a random GP fault if the reset handler executes "within" ceph_msg_revoke_incoming(): ... rbd_obj_request_end ceph_osdc_cancel_request __unregister_request ceph_osdc_put_request ceph_msg_revoke_incoming ... osd_reset __kick_osd_requests __reset_osd remove_osd ceph_con_close reset_connection in_msg->con> put_osd

con use> <-- !!! If ceph_msg_revoke_incoming() executes "before" the reset handler, osd/con will be leaked because ceph_msg_revoke_incoming() clears con->in_msg but doesn't put con ref, while reset_connection() only puts con ref if con->in_msg != NULL. The current msg->con scheme was introduced by commits 38941f8031bf ("libceph: have messages point to their connection") and 92ce034b5a74 ("libceph: have messages take a connection reference"), which defined when messages get associated with a connection and when that association goes away. Part of the problem is that this association is supposed to go away in much too many places; closing this race entirely requires either a rework of the existing or an addition of a new layer of synchronization. In lieu of that, we can make it *much* less likely to hit by disassociating messages only on their destruction and resend through a different connection. This makes the code simpler and is probably a good thing to do regardless - this patch adds a msg_con_set() helper which is is called from only three places: ceph_con_send() and ceph_con_in_msg_alloc() to set msg->con and ceph_msg_release() to clear it. Signed-off-by: Ilya Dryomov

libceph: add nocephx_sign_messages option

2015-11-02T22:37:46+00:00

Support for message signing was merged into 3.19, along with nocephx_require_signatures option. But, all that option does is allow the kernel client to talk to clusters that don't support MSG_AUTH feature bit. That's pretty useless, given that it's been supported since bobtail. Meanwhile, if one disables message signing on the server side with "cephx sign messages = false", it becomes impossible to use the kernel client since it expects messages to be signed if MSG_AUTH was negotiated. Add nocephx_sign_messages option to support this use case. Signed-off-by: Ilya Dryomov

libceph: stop duplicating client fields in messenger

2015-11-02T22:37:46+00:00

supported_features and required_features serve no purpose at all, while nocrc and tcp_nodelay belong to ceph_options::flags. Signed-off-by: Ilya Dryomov

libceph: msg signing callouts don't need con argument

2015-11-02T22:37:45+00:00

We can use msg->con instead - at the point we sign an outgoing message or check the signature on the incoming one, msg->con is always set. We wouldn't know how to sign a message without an associated session (i.e. msg->con == NULL) and being able to sign a message using an explicitly provided authorizer is of no use. Signed-off-by: Ilya Dryomov

libceph: use local variable cursor instead of &msg->cursor

2015-11-02T22:36:47+00:00

Use local variable cursor in place of &msg->cursor in read_partial_msg_data() and write_partial_msg_data(). Signed-off-by: Shraddha Barke Signed-off-by: Ilya Dryomov

libceph: don't access invalid memory in keepalive2 path

2015-09-17T17:14:15+00:00

This struct ceph_timespec ceph_ts; ... con_out_kvec_add(con, sizeof(ceph_ts), &ceph_ts); wraps ceph_ts into a kvec and adds it to con->out_kvec array, yet ceph_ts becomes invalid on return from prepare_write_keepalive(). As a result, we send out bogus keepalive2 stamps. Fix this by encoding into a ceph_timespec member, similar to how acks are read and written. Signed-off-by: Ilya Dryomov Reviewed-by: Yan, Zheng

libceph: check data_len in ->alloc_msg()

2015-09-09T06:52:17+00:00

Only ->alloc_msg() should check data_len of the incoming message against the preallocated ceph_msg, doing it in the messenger is not right. The contract is that either ->alloc_msg() returns a ceph_msg which will fit all of the portions of the incoming message, or it returns NULL and possibly sets skip, signaling whether NULL is due to an -ENOMEM. ->alloc_msg() should be the only place where we make the skip/no-skip decision. I stumbled upon this while looking at con/osd ref counting. Right now, if we get a non-extent message with a larger data portion than we are prepared for, ->alloc_msg() returns a ceph_msg, and then, when we skip it in the messenger, we don't put the con/osd ref acquired in ceph_con_in_msg_alloc() (which is normally put in process_message()), so this also fixes a memory leak. An existing BUG_ON in ceph_msg_data_cursor_init() ensures we don't corrupt random memory should a buggy ->alloc_msg() return an unfit ceph_msg. While at it, I changed the "unknown tid" dout() to a pr_warn() to make sure all skips are seen and unified format strings. Signed-off-by: Ilya Dryomov Reviewed-by: Alex Elder