Commit Graph

191 Commits

Author SHA1 Message Date
Alex Elder
4c59b4a278 libceph: collapse all data items into one
It turns out that only one of the data item types is ever used at
any one time in a single message (currently).
    - A page array is used by the osd client (on behalf of the file
      system) and by rbd.  Only one osd op (and therefore at most
      one data item) is ever used at a time by rbd.  And the only
      time the file system sends two, the second op contains no
      data.
    - A bio is only used by the rbd client (and again, only one
      data item per message)
    - A page list is used by the file system and by rbd for outgoing
      data, but only one op (and one data item) at a time.

We can therefore collapse all three of our data item fields into a
single field "data", and depend on the messenger code to properly
handle it based on its type.

This allows us to eliminate quite a bit of duplicated code.

This is related to:
    http://tracker.ceph.com/issues/4429

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:30 -07:00
Alex Elder
686be20875 libceph: get rid of read helpers
Now that read_partial_message_pages() and read_partial_message_bio()
are literally identical functions we can factor them out.  They're
pretty simple as well, so just move their relevant content into
read_partial_msg_data().

This is and previous patches together resolve:
    http://tracker.ceph.com/issues/4428

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:29 -07:00
Alex Elder
61fcdc97c0 libceph: no outbound zero data
There is handling in write_partial_message_data() for the case where
only the length of--and no other information about--the data to be
sent has been specified.  It uses the zero page as the source of
data to send in this case.

This case doesn't occur.  All message senders set up a page array,
pagelist, or bio describing the data to be sent.  So eliminate the
block of code that handles this (but check and issue a warning for
now, just in case it happens for some reason).

This resolves:
    http://tracker.ceph.com/issues/4426

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:28 -07:00
Alex Elder
878efabd32 libceph: use cursor for inbound data pages
The cursor code for a page array selects the right page, page
offset, and length to use for a ceph_tcp_recvpage() call, so
we can use it to replace a block in read_partial_message_pages().

This partially resolves:
    http://tracker.ceph.com/issues/4428

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:27 -07:00
Alex Elder
6518be47f9 libceph: kill ceph message bio_iter, bio_seg
The bio_iter and bio_seg fields in a message are no longer used, we
use the cursor instead.  So get rid of them and the functions that
operate on them them.

This is related to:
    http://tracker.ceph.com/issues/4428

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:26 -07:00
Alex Elder
463207aa40 libceph: use cursor for bio reads
Replace the use of the information in con->in_msg_pos for incoming
bio data.  The old in_msg_pos and the new cursor mechanism do
basically the same thing, just slightly differently.

The main functional difference is that in_msg_pos keeps track of the
length of the complete bio list, and assumed it was fully consumed
when that many bytes had been transferred.  The cursor does not assume
a length, it simply consumes all bytes in the bio list.  Because the
only user of bio data is the rbd client, and because the length of a
bio list provided by rbd client always matches the number of bytes
in the list, both ways of tracking length are equivalent.

In addition, for in_msg_pos the initial bio vector is selected as
the initial value of the bio->bi_idx, while the cursor assumes this
is zero.  Again, the rbd client always passes 0 as the initial index
so the effect is the same.

Other than that, they basically match:
    in_msg_pos      cursor
    ----------      ------
    bio_iter        bio
    bio_seg         vec_index
    page_pos        page_offset

The in_msg_pos field is initialized by a call to init_bio_iter().
The bio cursor is initialized by ceph_msg_data_cursor_init().
Both now happen in the same spot, in prepare_message_data().

The in_msg_pos field is advanced by a call to in_msg_pos_next(),
which updates page_pos and calls iter_bio_next() to move to the next
bio vector, or to the next bio in the list.  The cursor is advanced
by ceph_msg_data_advance().  That isn't currently happening so
add a call to that in in_msg_pos_next().

Finally, the next piece of data to use for a read is determined
by a bunch of lines in read_partial_message_bio().  Those can be
replaced by an equivalent ceph_msg_data_bio_next() call.

This partially resolves:
    http://tracker.ceph.com/issues/4428

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:25 -07:00
Alex Elder
25aff7c559 libceph: record residual bytes for all message data types
All of the data types can use this, not just the page array.  Until
now, only the bio type doesn't have it available, and only the
initiator of the request (the rbd client) is able to supply the
length of the full request without re-scanning the bio list.  Change
the cursor init routines so the length is supplied based on the
message header "data_len" field, and use that length to intiialize
the "resid" field of the cursor.

In addition, change the way "last_piece" is defined so it is based
on the residual number of bytes in the original request.  This is
necessary (at least for bio messages) because it is possible for
a read request to succeed without consuming all of the space
available in the data buffer.

This resolves:
    http://tracker.ceph.com/issues/4427

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:24 -07:00
Alex Elder
28a89ddece libceph: drop pages parameter
The value passed for "pages" in read_partial_message_pages() is
always the pages pointer from the incoming message, which can be
derived inside that function.  So just get rid of the parameter.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:17:23 -07:00
Alex Elder
888334f966 libceph: initialize data fields on last msg put
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>
2013-05-01 21:17:22 -07:00
Sage Weil
20e55c4cc7 libceph: clear messenger auth_retry flag when we authenticate
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>
2013-05-01 21:17:11 -07:00
Sage Weil
3a23083bda libceph: implement RECONNECT_SEQ feature
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>
2013-05-01 21:17:09 -07:00
Alex Elder
8a166d0536 libceph: more cleanup of write_partial_msg_pages()
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>
2013-05-01 21:17:06 -07:00
Alex Elder
9d2a06c275 libceph: kill message trail
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>
2013-05-01 21:17:05 -07:00
Alex Elder
e766d7b55e libceph: implement pages array cursor
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>
2013-05-01 21:17:01 -07:00
Alex Elder
6aaa4511de libceph: implement bio message data item cursor
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>
2013-05-01 21:16:59 -07:00
Alex Elder
7fe1e5e57b libceph: use data cursor for message pagelist
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>
2013-05-01 21:16:58 -07:00
Alex Elder
dd236fcb65 libceph: prepare for other message data item types
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>
2013-05-01 21:16:57 -07:00
Alex Elder
fe38a2b67b libceph: start defining message data cursor
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>
2013-05-01 21:16:56 -07:00
Alex Elder
437945094f libceph: abstract message data
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>
2013-05-01 21:16:55 -07:00
Alex Elder
f9e15777af libceph: be explicit about message data representation
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>
2013-05-01 21:16:54 -07:00
Alex Elder
97fb1c7f66 libceph: define ceph_msg_has_*() data macros
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>
2013-05-01 21:16:53 -07:00
Alex Elder
35b6280899 libceph: define and use ceph_crc32c_page()
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>
2013-05-01 21:16:52 -07:00
Alex Elder
afb3d90e20 libceph: define and use ceph_tcp_recvpage()
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>
2013-05-01 21:16:51 -07:00
Alex Elder
34d2d2006c libceph: encapsulate reading message data
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>
2013-05-01 21:16:50 -07:00
Alex Elder
e387d525b0 libceph: small write_partial_msg_pages() refactor
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>
2013-05-01 21:16:48 -07:00
Alex Elder
78625051b5 libceph: consolidate message prep code
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>
2013-05-01 21:16:47 -07:00
Alex Elder
bae6acd9c6 libceph: use local variables for message positions
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>
2013-05-01 21:16:46 -07:00
Alex Elder
98a0370898 libceph: don't clear bio_iter in prepare_write_message()
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>
2013-05-01 21:16:45 -07:00
Alex Elder
07aa155878 libceph: activate message data assignment checks
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/4263
    http://tracker.ceph.com/issues/4284

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
2013-05-01 21:16:44 -07:00
Alex Elder
4a73ef27ad libceph: record message data byte length
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>
2013-05-01 21:16:42 -07:00
Alex Elder
ebf18f4709 ceph: only set message data pointers if non-empty
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>
2013-05-01 21:16:41 -07:00
Alex Elder
27fa83852b libceph: isolate other message data fields
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>
2013-05-01 21:16:40 -07:00
Alex Elder
f1baeb2b9f libceph: set page info with byte length
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>
2013-05-01 21:16:39 -07:00
Alex Elder
02afca6ca0 libceph: isolate message page field manipulation
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>
2013-05-01 21:16:38 -07:00
Alex Elder
9516e45b25 libceph: simplify new message initialization
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>
2013-05-01 21:16:35 -07:00
Alex Elder
35c7bfbcd4 libceph: advance pagelist with list_rotate_left()
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>
2013-05-01 21:16:34 -07:00
Alex Elder
e788182fa6 libceph: define and use in_msg_pos_next()
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>
2013-05-01 21:16:33 -07:00
Alex Elder
b3d56fab33 libceph: kill args in read_partial_message_bio()
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>
2013-05-01 21:16:32 -07:00
Alex Elder
e1dcb128f8 libceph: change type of ceph_tcp_sendpage() "more"
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>
2013-05-01 21:16:31 -07:00
Alex Elder
6ebc8b32b3 libceph: minor byte order problems in read_partial_message()
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>
2013-05-01 21:16:30 -07:00
Alex Elder
7b11ba3758 libceph: define CEPH_MSG_MAX_MIDDLE_LEN
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>
2013-05-01 21:16:29 -07:00
Alex Elder
4137577ae3 libceph: clean up skipped message logic
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>
2013-05-01 21:16:28 -07:00
Alex Elder
53ded495c6 libceph: define mds_alloc_msg() method
The only user of the ceph messenger that doesn't define an alloc_msg
method is the mds client.  Define one, such that it works just like
it did before, and simplify ceph_con_in_msg_alloc() by assuming the
alloc_msg method is always present.

This and the next patch resolve:
    http://tracker.ceph.com/issues/4322

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
2013-05-01 21:16:19 -07:00
Alex Elder
1d866d1c31 libceph: drop mutex while allocating a message
In ceph_con_in_msg_alloc(), if no alloc_msg method is defined for a
connection a new message is allocated with ceph_msg_new().

Drop the mutex before making this call, and make sure we're still
connected when we get it back again.

This is preparing for the next patch, which ensures all connections
define an alloc_msg method, and then handles them all the same way.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
2013-05-01 21:16:18 -07:00
Alex Elder
ec02a2f2ff libceph: kill ceph_msg->pagelist_count
The pagelist_count field is never actually used, so get rid of it.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:16:16 -07:00
Alex Elder
d4b515fa10 libceph: distinguish page array and pagelist count
Use distinct fields for tracking the number of pages in a message's
page array and in a message's page list.  Currently only one or the
other is used at a time, but that will be changing soon.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:14:28 -07:00
Alex Elder
07c09b7255 libceph: make ceph_msg->bio_seg be unsigned
The bio_seg field is used by the ceph messenger in iterating through
a bio.  It should never have a negative value, so make it an
unsigned.  (I contemplated making it unsigned short to match the
struct bio definition, but it offered no benefit.)

Change variables used to hold bio_seg values to all be unsigned as
well.  Change two variable names in init_bio_iter() to match the
convention used everywhere else.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:14:23 -07:00
Alex Elder
49659416ba libceph: use a do..while loop in con_work()
This just converts a manually-implemented loop into a do..while loop
in con_work().  It also moves handling of EAGAIN inside the blocks
where it's already been determined an error code was returned.

Also update a few dout() calls near the affected code for
consistency.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-25 15:37:37 -06:00
Alex Elder
b6e7b6a119 libceph: use a flag to indicate a fault has occurred
This just rearranges the logic in con_work() a little bit so that a
flag is used to indicate a fault has occurred.  This allows both the
fault and non-fault case to be handled the same way and avoids a
couple of nearly consecutive gotos.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-25 15:37:32 -06:00
Alex Elder
9320926420 libceph: separate non-locked fault handling
An error occurring on a ceph connection is treated as a fault,
causing the connection to be reset.  The initial part of this fault
handling has to be done while holding the connection mutex, but
it must then be dropped for the last part.

Separate the part of this fault handling that executes without the
lock into its own function, con_fault_finish().  Move the call to
this new function, as well as call that drops the connection mutex,
into ceph_fault().  Rename that function con_fault() to reflect that
it's only handling the connection part of the fault handling.

The motivation for this was a warning from sparse about the locking
being done here.  Rearranging things this way keeps all the mutex
manipulation within ceph_fault(), and this stops sparse from
complaining.

This partially resolves:
    http://tracker.ceph.com/issues/4184

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-25 15:37:28 -06:00