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libceph: (re)initialize bio_iter on start of message receive 

Previously, we were opportunistically initializing the bio_iter if it
appeared to be uninitialized in the middle of the read path.  The problem
is that a sequence like:

 - start reading message
 - initialize bio_iter
 - read half a message
 - messenger fault, reconnect
 - restart reading message
 - ** bio_iter now non-NULL, not reinitialized **
 - read past end of bio, crash

Instead, initialize the bio_iter unconditionally when we allocate/claim
the message for read.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
This commit is contained in:
Sage Weil 2012-07-30 16:20:25 -07:00
parent 6194ea895e
commit a410702697
1 changed files with 6 additions and 5 deletions
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11
net/ceph/messenger.c
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@ -1872,6 +1872,11 @@ static int read_partial_message(struct ceph_connection *con)
else
con->in_msg_pos.page_pos = 0;
con->in_msg_pos.data_pos = 0;
#ifdef CONFIG_BLOCK
if (m->bio)
init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
#endif
}
/* front */
@ -1888,10 +1893,6 @@ static int read_partial_message(struct ceph_connection *con)
if (ret <= 0)
return ret;
}
#ifdef CONFIG_BLOCK
if (m->bio && !m->bio_iter)
init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
#endif
/* (page) data */
while (con->in_msg_pos.data_pos < data_len) {
@ -1902,7 +1903,7 @@ static int read_partial_message(struct ceph_connection *con)
return ret;
#ifdef CONFIG_BLOCK
} else if (m->bio) {
BUG_ON(!m->bio_iter);
ret = read_partial_message_bio(con,
&m->bio_iter, &m->bio_seg,
data_len, do_datacrc);