Create a slab cache to manage ceph_msg_data structure allocation.
This is part of:
http://tracker.ceph.com/issues/3926
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Create a slab cache to manage ceph_msg structure allocation.
This is part of:
http://tracker.ceph.com/issues/3926
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This patch makes four small changes in the ceph messenger.
While getting copyup functionality working I found two bugs in the
messenger. Existing paths through the code did not trigger these
problems, but they're fixed here:
- In ceph_msg_data_pagelist_cursor_init(), the cursor's
last_piece field was being checked against the length
supplied. This was OK until this commit: ccba6d98 libceph:
implement multiple data items in a message That commit changed
the cursor init routines to allow lengths to be supplied that
exceeded the size of the current data item. Because of this,
we have to use the assigned cursor resid field rather than the
provided length in determining whether the cursor points to
the last piece of a data item.
- In ceph_msg_data_add_pages(), a BUG_ON() was erroneously
catching attempts to add page data to a message if the message
already had data assigned to it. That was OK until that same
commit, at which point it was fine for messages to have
multiple data items. It slipped through because that BUG_ON()
call was present twice in that function. (You can never be too
careful.)
In addition two other minor things are changed:
- In ceph_msg_data_cursor_init(), the local variable "data" was
getting assigned twice.
- In ceph_msg_data_advance(), it was assumed that the
type-specific advance routine would set new_piece to true
after it advanced past the last piece. That may have been
fine, but since we check for that case we might as well set it
explicitly in ceph_msg_data_advance().
This resolves:
http://tracker.ceph.com/issues/4762
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Change the names of the functions that put data on a pagelist to
reflect that we're adding to whatever's already there rather than
just setting it to the one thing. Currently only one data item is
ever added to a message, but that's about to change.
This resolves:
http://tracker.ceph.com/issues/2770
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This patch adds support to the messenger for more than one data item
in its data list.
A message data cursor has two more fields to support this:
- a count of the number of bytes left to be consumed across
all data items in the list, "total_resid"
- a pointer to the head of the list (for validation only)
The cursor initialization routine has been split into two parts: the
outer one, which initializes the cursor for traversing the entire
list of data items; and the inner one, which initializes the cursor
to start processing a single data item.
When a message cursor is first initialized, the outer initialization
routine sets total_resid to the length provided. The data pointer
is initialized to the first data item on the list. From there, the
inner initialization routine finishes by setting up to process the
data item the cursor points to.
Advancing the cursor consumes bytes in total_resid. If the resid
field reaches zero, it means the current data item is fully
consumed. If total_resid indicates there is more data, the cursor
is advanced to point to the next data item, and then the inner
initialization routine prepares for using that. (A check is made at
this point to make sure we don't wrap around the front of the list.)
The type-specific init routines are modified so they can be given a
length that's larger than what the data item can support. The resid
field is initialized to the smaller of the provided length and the
length of the entire data item.
When total_resid reaches zero, we're done.
This resolves:
http://tracker.ceph.com/issues/3761
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In place of the message data pointer, use a list head which links
through message data items. For now we only support a single entry
on that list.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Rather than having a ceph message data item point to the cursor it's
associated with, have the cursor point to a data item. This will
allow a message cursor to be used for more than one data item.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
A message will only be processing a single data item at a time, so
there's no need for each data item to have its own cursor.
Move the cursor embedded in the message data structure into the
message itself. To minimize the impact, keep the data->cursor
field, but make it be a pointer to the cursor in the message.
Move the definition of ceph_msg_data above ceph_msg_data_cursor so
the cursor can point to the data without a forward definition rather
than vice-versa.
This and the upcoming patches are part of:
http://tracker.ceph.com/issues/3761
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The bio is the only data item type that doesn't record its full
length. Fix that.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
We know the length of our message buffers. If we get a message
that's too long, just dump it and ignore it. If skip was set
then con->in_msg won't be valid, so be careful not to dereference
a null pointer in the process.
This resolves:
http://tracker.ceph.com/issues/4664
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This patch:
15a0d7b libceph: record message data length
did not enclose some bio-specific code inside CONFIG_BLOCK as
it should have. Fix that.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In prepare_message_data(), the length used to initialize the cursor
is taken from the header of the message provided. I'm working
toward not using the header data length field to determine length in
outbound messages, and this is a step in that direction. For
inbound messages this will be set to be the actual number of bytes
that are arriving (which may be less than the total size of the data
buffer available).
This resolves:
http://tracker.ceph.com/issues/4589
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Keep track of the length of the data portion for a message in a
separate field in the ceph_msg structure. This information has
been maintained in wire byte order in the message header, but
that's going to change soon.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When a cursor for a page array data message is initialized it needs
to determine the initial value for cursor->last_piece. Currently it
just checks if length is less than a page, but that's not correct.
The data in the first page in the array will be offset by a page
offset based on the alignment recorded for the data. (All pages
thereafter will be aligned at the base of the page, so there's
no need to account for this except for the first page.)
Because this was wrong, there was a case where the length of a piece
would be calculated as all of the residual bytes in the message and
that plus the page offset could exceed the length of a page.
So fix this case. Make sure the sum won't wrap.
This resolves a third issue described in:
http://tracker.ceph.com/issues/4598
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Currently ceph_msg_data_pages_advance() allows the page offset value
to be PAGE_SIZE, apparently assuming ceph_msg_data_pages_next() will
treat it as 0. But that doesn't happen, and the result led to a
helpful assertion failure.
Change ceph_msg_data_pages_advance() to truncate the offset to 0
before returning if it reaches PAGE_SIZE.
Make a few other minor adjustments in this area (comments and a
better assertion) while modifying it.
This resolves a second issue described in:
http://tracker.ceph.com/issues/4598
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
It's OK for the result of a read to come back with fewer bytes than
were requested. So don't trigger a BUG() in that case when
initializing the data cursor.
This resolves the first problem described in:
http://tracker.ceph.com/issues/4598
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Begin the transition from a single message data item to a list of
them by replacing the "data" structure in a message with a pointer
to a ceph_msg_data structure.
A null pointer will indicate the message has no data; replace the
use of ceph_msg_has_data() with a simple check for a null pointer.
Create functions ceph_msg_data_create() and ceph_msg_data_destroy()
to dynamically allocate and free a data item structure of a given type.
When a message has its data item "set," allocate one of these to
hold the data description, and free it when the last reference to
the message is dropped.
This partially resolves:
http://tracker.ceph.com/issues/4429
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The *_msg_pos_next() functions do little more than call
ceph_msg_data_advance(). Replace those wrapper functions with
a simple call to ceph_msg_data_advance().
This cleanup 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>
In write_partial_message_data() we aggregate the crc for the data
portion of the message as each new piece of the data item is
encountered. Because it was computed *before* sending the data, if
an attempt to send a new piece resulted in 0 bytes being sent, the
crc crc across that piece would erroneously get computed again and
added to the aggregate result. This would occasionally happen in
the evnet of a connection failure.
The crc value isn't really needed until the complete value is known
after sending all data, so there's no need to compute it before
sending.
So don't calculate the crc for a piece until *after* we know at
least one byte of it has been sent. That will avoid this problem.
This resolves:
http://tracker.ceph.com/issues/4450
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
The only remaining field in the ceph_msg_pos structure is
did_page_crc. In the new cursor model of things that flag (or
something like it) belongs in the cursor.
Define a new field "need_crc" in the cursor (which applies to all
types of data) and initialize it to true whenever a cursor is
initialized.
In write_partial_message_data(), the data CRC still will be computed
as before, but it will check the cursor->need_crc field to determine
whether it's needed. Any time the cursor is advanced to a new piece
of a data item, need_crc will be set, and this will cause the crc
for that entire piece to be accumulated into the data crc.
In write_partial_message_data() the intermediate crc value is now
held in a local variable so it doesn't have to be byte-swapped so
many times. In read_partial_msg_data() we do something similar
(but mainly for consistency there).
With that, the ceph_msg_pos structure can go away, and it no longer
needs to be passed as an argument to prepare_message_data().
This cleanup 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>
All but one of the fields in the ceph_msg_pos structure are now
never used (only assigned), so get rid of them. This allows
several small blocks of code to go away.
This is cleanup of old code related to:
http://tracker.ceph.com/issues/4428
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Use the "resid" field of a cursor rather than finding when the
message data position has moved up to meet the data length to
determine when all data has been sent or received in
write_partial_message_data() and read_partial_msg_data().
This is cleanup of old code related to:
http://tracker.ceph.com/issues/4428
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Alex Elder