When the last reference to a ceph message is dropped,
ceph_msg_last_put() is called to clean things up.
For "normal" messages (allocated via ceph_msg_new() rather than
being allocated from a memory pool) it's sufficient to just release
resources. But for a mempool-allocated message we actually have to
re-initialize the data fields in the message back to initial state
so they're ready to go in the event the message gets reused.
Some of this was already done; this fleshes it out so it's done
more completely.
This resolves:
http://tracker.ceph.com/issues/4540
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd expects the transaction ids of arriving request messages from
a given client to a given osd to increase monotonically. So the osd
client needs to send its requests in ascending tid order.
The transaction id for a request is set at the time it is
registered, in __register_request(). This is also where the request
gets placed at the end of the osd client's unsent messages list.
At the end of ceph_osdc_start_request(), the request message for a
newly-mapped osd request is supplied to the messenger to be sent
(via __send_request()). If any other messages were present in the
osd client's unsent list at that point they would be sent *after*
this new request message.
Because those unsent messages have already been registered, their
tids would be lower than the newly-mapped request message, and
sending that message first can violate the tid ordering rule.
Rather than sending the new request only, send all queued requests
(including the new one) at that point in ceph_osdc_start_request().
This ensures the tid ordering property is preserved.
With this in place, all messages should now be sent in tid order
regardless of whether they're being sent for the first time or
re-sent as a result of a call to osd_reset().
This resolves:
http://tracker.ceph.com/issues/4392
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-off-by: Sage Weil <sage@inktank.com>
In __map_request(), when adding a request to an osd client's unsent
list, add it to the tail rather than the head. That way the newest
entries (with the highest tid value) will be last.
Maintain an osd's request list in order of increasing tid also.
Finally--to be consistent--maintain an osd client's "notarget" list
in that order as well.
This partially resolves:
http://tracker.ceph.com/issues/4392
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-off-by: Sage Weil <sage@inktank.com>
The osd expects incoming requests for a given object from a given
client to arrive in order, with the tid for each request being
greater than the tid for requests that have already arrived. This
patch fixes two places the osd client might not maintain that
ordering.
For the osd client, the connection fault method is osd_reset().
That function calls __reset_osd() to close and re-open the
connection, then calls __kick_osd_requests() to cause all
outstanding requests for the affected osd to be re-sent after
the connection has been re-established.
When an osd is reset, any in-flight messages will need to be
re-sent. An osd client maintains distinct lists for unsent and
in-flight messages. Meanwhile, an osd maintains a single list of
all its requests (both sent and un-sent). (Each message is linked
into two lists--one for the osd client and one list for the osd.)
To process an osd "kick" operation, the request list for the *osd*
is traversed, and each request is moved off whichever osd *client*
list it was on (unsent or sent) and placed onto the osd client's
unsent list. (It remains where it is on the osd's request list.)
When that is done, osd_reset() calls __send_queued() to cause each
of the osd client's unsent messages to be sent.
OK, with that background...
As the osd request list is traversed each request is prepended to
the osd client's unsent list in the order they're seen. The effect
of this is to reverse the order of these requests as they are put
(back) onto the unsent list.
Instead, build up a list of only the requests for an osd that have
already been sent (by checking their r_sent flag values). Once an
unsent request is found, stop examining requests and prepend the
requests that need re-sending to the osd client's unsent list.
Preserve the original order of requests in the process (previously
re-queued requests were reversed in this process). Because they
have already been sent, they will have lower tids than any request
already present on the unsent list.
Just below that, traverse the linger list in forward order as
before, but add them to the *tail* of the list rather than the head.
These requests get re-registered, and in the process are give a new
(higher) tid, so the should go at the end.
This partially resolves:
http://tracker.ceph.com/issues/4392
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-off-by: Sage Weil <sage@inktank.com>
Since we no longer drop the request mutex between registering and
mapping an osd request in ceph_osdc_start_request(), there is no
chance of a race with kick_requests().
We can now therefore map and send the new request unconditionally
(but we'll issue a warning should it ever occur).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-off-by: Sage Weil <sage@inktank.com>
One of the first things ceph_osdc_start_request() does is register
the request. It then acquires the osd client's map semaphore and
request mutex and proceeds to map and send the request.
There is no reason the request has to be registered before acquiring
the map semaphore. So hold off doing so until after the map
semaphore is held.
Since register_request() is nothing more than a wrapper around
__register_request(), call the latter function instead, after
acquiring the request mutex.
That leaves register_request() unused, so get rid of it.
This partially resolves:
http://tracker.ceph.com/issues/4392
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-off-by: Sage Weil <sage@inktank.com>
The auth code is called from a variety of contexts, include the mon_client
(protected by the monc's mutex) and the messenger callbacks (currently
protected by nothing). Avoid chaos by protecting all auth state with a
mutex. Nothing is blocking, so this should be simple and lightweight.
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Use wrapper functions that check whether the auth op exists so that callers
do not need a bunch of conditional checks. Simplifies the external
interface.
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Currently the messenger calls out to a get_authorizer con op, which will
create a new authorizer if it doesn't yet have one. In the meantime, when
we rotate our service keys, the authorizer doesn't get updated. Eventually
it will be rejected by the server on a new connection attempt and get
invalidated, and we will then rebuild a new authorizer, but this is not
ideal.
Instead, if we do have an authorizer, call a new update_authorizer op that
will verify that the current authorizer is using the latest secret. If it
is not, we will build a new one that does. This avoids the transient
failure.
This fixes one of the sorry sequence of events for bug
http://tracker.ceph.com/issues/4282
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
We were invalidating the authorizer by removing the ticket handler
entirely. This was effective in inducing us to request a new authorizer,
but in the meantime it mean that any authorizer we generated would get a
new and initialized handler with secret_id=0, which would always be
rejected by the server side with a confusing error message:
auth: could not find secret_id=0
cephx: verify_authorizer could not get service secret for service osd secret_id=0
Instead, simply clear the validity field. This will still induce the auth
code to request a new secret, but will let us continue to use the old
ticket in the meantime. The messenger code will probably continue to fail,
but the exponential backoff will kick in, and eventually the we will get a
new (hopefully more valid) ticket from the mon and be able to continue.
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
We maintain a counter of failed auth attempts to allow us to retry once
before failing. However, if the second attempt succeeds, the flag isn't
cleared, which makes us think auth failed again later when the connection
resets for other reasons (like a socket error).
This is one part of the sorry sequence of events in bug
http://tracker.ceph.com/issues/4282
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
This is an old protocol extension that allows the client and server to
avoid resending old messages after a reconnect (following a socket error).
Instead, the exchange their sequence numbers during the handshake. This
avoids sending a bunch of useless data over the socket.
It has been supported in the server code since v0.22 (Sep 2010).
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
We should advance the user data pointer by _len_ instead of _written_.
_len_ is the data length written in each iteration while _written_ is the
accumulated data length we have writtent out.
Signed-off-by: Henry C Chang <henry.cy.chang@gmail.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Tested-by: Sage Weil <sage@inktank.com>
Current ceph code tracks directory's completeness in two places.
ceph_readdir() checks i_release_count to decide if it can set the
I_COMPLETE flag in i_ceph_flags. All other places check the I_COMPLETE
flag. This indirection introduces locking complexity.
This patch adds a new variable i_complete_count to ceph_inode_info.
Set i_release_count's value to it when marking a directory complete.
By comparing the two variables, we know if a directory is complete
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Basically all cases in write_partial_msg_pages() use the cursor, and
as a result we can simplify that function quite a bit.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The wart that is the ceph message trail can now be removed, because
its only user was the osd client, and the previous patch made that
no longer the case.
The result allows write_partial_msg_pages() to be simplified
considerably.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The osd trail is a pagelist, used only for a CALL osd operation
to hold the class and method names, along with any input data for
the call.
It is only currently used by the rbd client, and when it's used it
is the only bit of outbound data in the osd request. Since we
already support (non-trail) pagelist data in a message, we can
just save this outbound CALL data in the "normal" pagelist rather
than the trail, and get rid of the trail entirely.
The existing pagelist support depends on the pagelist being
dynamically allocated, and ownership of it is passed to the
messenger once it's been attached to a message. (That is to say,
the messenger releases and frees the pagelist when it's done with
it). That means we need to dynamically allocate the pagelist also.
Note that we simply assert that the allocation of a pagelist
structure succeeds. Appending to a pagelist might require a dynamic
allocation, so we're already assuming we won't run into trouble
doing so (we're just ignore any failures--and that should be fixed
at some point).
This resolves:
http://tracker.ceph.com/issues/4407
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Add support for recording a ceph pagelist as data associated with an
osd request.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The length of outgoing data in an osd request is dependent on the
osd ops that are embedded in that request. Each op is encoded into
a request message using osd_req_encode_op(), so that should be used
to determine the amount of outgoing data implied by the op as it
is encoded.
Have osd_req_encode_op() return the number of bytes of outgoing data
implied by the op being encoded, and accumulate and use that in
ceph_osdc_build_request().
As a result, ceph_osdc_build_request() no longer requires its "len"
parameter, so get rid of it.
Using the sum of the op lengths rather than the length provided is
a valid change because:
- The only callers of osd ceph_osdc_build_request() are
rbd and the osd client (in ceph_osdc_new_request() on
behalf of the file system).
- When rbd calls it, the length provided is only non-zero for
write requests, and in that case the single op has the
same length value as what was passed here.
- When called from ceph_osdc_new_request(), (it's not all that
easy to see, but) the length passed is also always the same
as the extent length encoded in its (single) write op if
present.
This resolves:
http://tracker.ceph.com/issues/4406
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Implement and use cursor routines for page array message data items
for outbound message data.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Implement and use cursor routines for bio message data items for
outbound message data.
(See the previous commit for reasoning in support of the changes
in out_msg_pos_next().)
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Switch to using the message cursor for the (non-trail) outgoing
pagelist data item in a message if present.
Notes on the logic changes in out_msg_pos_next():
- only the mds client uses a ceph pagelist for message data;
- if the mds client ever uses a pagelist, it never uses a page
array (or anything else, for that matter) for data in the same
message;
- only the osd client uses the trail portion of a message data,
and when it does, it never uses any other data fields for
outgoing data in the same message; and finally
- only the rbd client uses bio message data (never pagelist).
Therefore out_msg_pos_next() can assume:
- if we're in the trail portion of a message, the message data
pagelist, data, and bio can be ignored; and
- if there is a page list, there will never be any a bio or page
array data, and vice-versa.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This just inserts some infrastructure in preparation for handling
other types of ceph message data items. No functional changes,
just trying to simplify review by separating out some noise.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This patch lays out the foundation for using generic routines to
manage processing items of message data.
For simplicity, we'll start with just the trail portion of a
message, because it stands alone and is only present for outgoing
data.
First some basic concepts. We'll use the term "data item" to
represent one of the ceph_msg_data structures associated with a
message. There are currently four of those, with single-letter
field names p, l, b, and t. A data item is further broken into
"pieces" which always lie in a single page. A data item will
include a "cursor" that will track state as the memory defined by
the item is consumed by sending data from or receiving data into it.
We define three routines to manipulate a data item's cursor: the
"init" routine; the "next" routine; and the "advance" routine. The
"init" routine initializes the cursor so it points at the beginning
of the first piece in the item. The "next" routine returns the
page, page offset, and length (limited by both the page and item
size) of the next unconsumed piece in the item. It also indicates
to the caller whether the piece being returned is the last one in
the data item.
The "advance" routine consumes the requested number of bytes in the
item (advancing the cursor). This is used to record the number of
bytes from the current piece that were actually sent or received by
the network code. It returns an indication of whether the result
means the current piece has been fully consumed. This is used by
the message send code to determine whether it should calculate the
CRC for the next piece processed.
The trail of a message is implemented as a ceph pagelist. The
routines defined for it will be usable for non-trail pagelist data
as well.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Group the types of message data into an abstract structure with a
type indicator and a union containing fields appropriate to the
type of data it represents. Use this to represent the pages,
pagelist, bio, and trail in a ceph message.
Verify message data is of type NONE in ceph_msg_data_set_*()
routines. Since information about message data of type NONE really
should not be interpreted, get rid of the other assertions in those
functions.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
A ceph message has a data payload portion. The memory for that data
(either the source of data to send or the location to place data
that is received) is specified in several ways. The ceph_msg
structure includes fields for all of those ways, but this
mispresents the fact that not all of them are used at a time.
Specifically, the data in a message can be in:
- an array of pages
- a list of pages
- a list of Linux bios
- a second list of pages (the "trail")
(The two page lists are currently only ever used for outgoing data.)
Impose more structure on the ceph message, making the grouping of
some of these fields explicit. Shorten the name of the
"page_alignment" field.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define and use macros ceph_msg_has_*() to determine whether to
operate on the pages, pagelist, bio, and trail fields of a message.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Factor out a common block of code that updates a CRC calculation
over a range of data in a page.
This and the preceding patches are related to:
http://tracker.ceph.com/issues/4403
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a new function ceph_tcp_recvpage() that behaves in a way
comparable to ceph_tcp_sendpage().
Rearrange the code in both read_partial_message_pages() and
read_partial_message_bio() so they have matching structure,
(similar to what's in write_partial_msg_pages()), and use
this new function.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Pull the code that reads the data portion into a message into
a separate function read_partial_msg_data().
Rename write_partial_msg_pages() to be write_partial_message_data()
to match its read counterpart, and to reflect its more generic
purpose.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define local variables page_offset and length to represent the range
of bytes within a page that will be sent by ceph_tcp_sendpage() in
write_partial_msg_pages().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In prepare_write_message_data(), various fields are initialized in
preparation for writing message data out. Meanwhile, in
read_partial_message(), there is essentially the same block of code,
operating on message variables associated with an incoming message.
Generalize prepare_write_message_data() so it works for both
incoming and outcoming messages, and use it in both spots. The
did_page_crc is not used for input (so it's harmless to initialize
it).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There are several places where a message's out_msg_pos or in_msg_pos
field is used repeatedly within a function. Use a local pointer
variable for this purpose to unclutter the code.
This and the upcoming cleanup patches are related to:
http://tracker.ceph.com/issues/4403
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
At one time it was necessary to clear a message's bio_iter field to
avoid a bad pointer dereference in write_partial_msg_pages().
That no longer seems to be the case. Here's why.
The message's bio fields represent (in this case) outgoing data.
Between where the bio_iter is made NULL in prepare_write_message()
and the call in that function to prepare_message_data(), the
bio fields are never used.
In prepare_message_data(), init-bio_iter() is called, and the result
of that overwrites the value in the message's bio_iter field.
Because it gets overwritten anyway, there is no need to set it to
NULL. So don't do it.
This resolves:
http://tracker.ceph.com/issues/4402
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The mds client no longer tries to assign zero-length message data,
and the osd client no longer sets its data info more than once.
This allows us to activate assertions in the messenger to verify
these things never happen.
This resolves both of these:
http://tracker.ceph.com/issues/4263http://tracker.ceph.com/issues/4284
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
When an incoming message is destined for the osd client, the
messenger calls the osd client's alloc_msg method. That function
looks up which request has the tid matching the incoming message,
and returns the request message that was preallocated to receive the
response. The response message is therefore known before the
request is even started.
Between the start of the request and the receipt of the response,
the request and its data fields will not change, so there's no
reason we need to hold off setting them. In fact it's preferable
to set them just once because it's more obvious that they're
unchanging.
So set up the fields describing where incoming data is to land in a
response message at the beginning of ceph_osdc_start_request().
Define a helper function that sets these fields, and use it to
set the fields for both outgoing data in the request message and
incoming data in the response.
This resolves:
http://tracker.ceph.com/issues/4284
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Record the number of bytes of data in a page array rather than the
number of pages in the array. It can be assumed that the page array
is of sufficient size to hold the number of bytes indicated (and
offset by the indicated alignment).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Change it so we only assign outgoing data information for messages
if there is outgoing data to send.
This then allows us to add a few more (currently commented-out)
assertions.
This is related to:
http://tracker.ceph.com/issues/4284
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Define ceph_msg_data_set_pagelist(), ceph_msg_data_set_bio(), and
ceph_msg_data_set_trail() to clearly abstract the assignment of the
remaining data-related fields in a ceph message structure. Use the
new functions in the osd client and mds client.
This partially resolves:
http://tracker.ceph.com/issues/4263
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When setting page array information for message data, provide the
byte length rather than the page count ceph_msg_data_set_pages().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a function ceph_msg_data_set_pages(), which more clearly
abstracts the assignment page-related fields for data in a ceph
message structure. Use this new function in the osd client and mds
client.
Ideally, these fields would never be set more than once (with
BUG_ON() calls to guarantee that). At the moment though the osd
client sets these every time it receives a message, and in the event
of a communication problem this can happen more than once. (This
will be resolved shortly, but setting up these helpers first makes
it all a bit easier to work with.)
Rearrange the field order in a ceph_msg structure to group those
that are used to define the possible data payloads.
This partially resolves:
http://tracker.ceph.com/issues/4263
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Record the byte count for an osd request rather than the page count.
The number of pages can always be derived from the byte count (and
alignment/offset) but the reverse is not true.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Rather than explicitly initializing many fields to 0, NULL, or false
in a newly-allocated message, just use kzalloc() for allocating new
messages. This will become a much more convenient way of doing
things anyway for upcoming patches that abstract the data field.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
While processing an outgoing pagelist (either the data pagelist or
trail) in a ceph message, the messenger cycles through each of the
pages on the list. This is accomplished in out_msg_pos_next(), if
the end of the first page on the list is reached, the first page is
moved to the end of the list.
There is a list operation, list_rotate_left(), which performs
exactly this operation, and by using it, what's really going on
becomes more obvious.
So replace these two list_move_tail() calls with list_rotate_left().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a new function in_msg_pos_next() to match out_msg_pos_next(),
and use it in place of code at the end of read_partial_message_pages()
and read_partial_message_bio().
Note that the page number is incremented and offset reset under
slightly different conditions from before. The result is
equivalent, however, as explained below.
Each time an incoming message is going to arrive, we find out how
much room is left--not surpassing the current page--and provide that
as the number of bytes to receive. So the amount we'll use is the
lesser of: all that's left of the entire request; and all that's
left in the current page.
If we received exactly how many were requested, we either reached
the end of the request or the end of the page. In the first case,
we're done, in the second, we move onto the next page in the array.
In all cases but (possibly) on the last page, after adding the
number of bytes received, page_pos == PAGE_SIZE. On the last page,
it doesn't really matter whether we increment the page number and
reset the page position, because we're done and we won't come back
here again. The code previously skipped over that last case,
basically. The new code handles that case the same as the others,
incrementing and resetting.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There is only one caller for read_partial_message_bio(), and it
always passes &msg->bio_iter and &bio_seg as the second and third
arguments. Furthermore, the message in question is always the
connection's in_msg, and we can get that inside the called function.
So drop those two parameters and use their derived equivalents.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Change the type of the "more" parameter from int to bool.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Some values printed are not (necessarily) in CPU order. We already
have a copy of the converted versions, so use them.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This is probably unnecessary but the code read as if it were wrong
in read_partial_message().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In ceph_con_in_msg_alloc() it is possible for a connection's
alloc_msg method to indicate an incoming message should be skipped.
By default, read_partial_message() initializes the skip variable
to 0 before it gets provided to ceph_con_in_msg_alloc().
The osd client, mon client, and mds client each supply an alloc_msg
method. The mds client always assigns skip to be 0.
The other two leave the skip value of as-is, or assigns it to zero,
except:
- if no (osd or mon) request having the given tid is found, in
which case skip is set to 1 and NULL is returned; or
- in the osd client, if the data of the reply message is not
adequate to hold the message to be read, it assigns skip
value 1 and returns NULL.
So the returned message pointer will always be NULL if skip is ever
non-zero.
Clean up the logic a bit in ceph_con_in_msg_alloc() to make this
state of affairs more obvious. Add a comment explaining how a null
message pointer can mean either a message that should be skipped or
a problem allocating a message.
This resolves:
http://tracker.ceph.com/issues/4324
Reported-by: Greg Farnum <greg@inktank.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
