Return error to original caller if register_session() fails.
Signed-off-by: NSage Weil <sage@newdream.net>

Prevent duplicate 'mds0 caps stale' message from spamming the console every
few seconds while the MDS restarts.  Set s_renew_requested earlier, so that
we only print the message once, even if we don't send an actual request.
Signed-off-by: NSage Weil <sage@newdream.net>

The wait_unsafe_requests() helper dropped the mdsc mutex to wait
for each request to complete, and then examined r_node to get the
next request after retaking the lock.  But the request completion
removes the request from the tree, so r_node was always undefined
at this point.  Since it's a small race, it usually led to a
valid request, but not always.  The result was an occasional
crash in rb_next() while dereferencing node->rb_left.

Fix this by clearing the rb_node when removing the request from
the request tree, and not walking off into the weeds when we
are done waiting for a request.  Since the request we waited on
will _always_ be out of the request tree, take a ref on the next
request, in the hopes that it won't be.  But if it is, it's ok:
we can start over from the beginning (and traverse over older read
requests again).
Signed-off-by: NSage Weil <sage@newdream.net>

The must_resend flag is always true, not false.  In any case, we can
just ignore it anyway.
Signed-off-by: NSage Weil <sage@newdream.net>

The tid is in the message header, not body.  Broken since 6df058c0.

No need to look at next mds session; just mark the request and be done.
(The old error path was broken too, but now it's gone.)
Signed-off-by: NSage Weil <sage@newdream.net>

Verify the mds session is currently registered before handling
incoming messages.  Clean up message handlers to pull mds out
of session->s_mds instead of less trustworthy src field.

Clean up con_{get,put} debug output.
Signed-off-by: NSage Weil <sage@newdream.net>

We need to be able to iterate over all caps on a session with a
possibly slow callback on each cap.  To allow this, we used to
prevent cap reordering while we were iterating.  However, we were
not safe from races with removal: removing the 'next' cap would
make the next pointer from list_for_each_entry_safe be invalid,
and cause a lock up or similar badness.

Instead, we keep an iterator pointer in the session pointing to
the current cap.  As before, we avoid reordering.  For removal,
if the cap isn't the current cap we are iterating over, we are
fine.  If it is, we clear cap->ci (to mark the cap as pending
removal) but leave it in the session list.  In iterate_caps, we
can safely finish removal and get the next cap pointer.

While we're at it, clean up put_cap to not take a cap reservation
context, as it was never used.
Signed-off-by: NSage Weil <sage@newdream.net>

Switch from radix tree to rbtree for snap realms.  This is much more
appropriate given that realm keys are few and far between.
Signed-off-by: NSage Weil <sage@newdream.net>

The rbtree is a more appropriate data structure than a radix_tree.  It
avoids extra memory usage and simplifies the code.

It also fixes a bug where the debugfs 'mdsc' file wasn't including the
most recent mds request.
Signed-off-by: NSage Weil <sage@newdream.net>

Add infrastructure to allow the mon_client to periodically renew its auth
credentials.  Also add a messenger callback that will force such a renewal
if a peer rejects our authenticator.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

Include a type/version in ceph_entity_addr and filepath.  Include extra
byte in filepath encoding as necessary.
Signed-off-by: NSage Weil <sage@newdream.net>

Both front and middle parts of the message are now being
allocated at the ceph_alloc_msg().
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>

Previously, if the MDS request was interrupted, we would unregister the
request and ignore any reply.  This could cause the caps or other cache
state to become out of sync.  (For instance, aborting dbench and doing
rm -r on clients would complain about a non-empty directory because the
client didn't realize it's aborted file create request completed.)

Even we don't unregister, we still can't process the reply normally because
we are no longer holding the caller's locks (like the dir i_mutex).

So, mark aborted operations with r_aborted, and in the reply handler, be
sure to process all the caps.  Do not process the namespace changes,
though, since we no longer will hold the dir i_mutex.  The dentry lease
state can also be ignored as it's more forgiving.
Signed-off-by: NSage Weil <sage@newdream.net>

Use the ceph_pagelist to encode the MDS reconnect message.  We change the
message encoding (protocol change!) at the same time to make our life
easier (we don't know how many snaprealms we have when we start encoding).

An empty message implies the session is closed/does not exist.
Signed-off-by: NSage Weil <sage@newdream.net>

Many (most?) message types include a transaction id.  By including it in
the fixed size header, we always have it available even when we are unable
to allocate memory for the (larger, variable sized) message body.  This
will allow us to error out the appropriate request instead of (silently)
dropping the reply.
Signed-off-by: NSage Weil <sage@newdream.net>

Avoid confusing iterate_session_caps(), flag the session while we are
iterating so that __touch_cap does not rearrange items on the list.

All other modifiers of session->s_caps do so under the protection of
s_mutex.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NSage Weil <sage@newdream.net>

Also, print fsid using standard format, NOT hex dump.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NSage Weil <sage@newdream.net>

The max_size increase request to the MDS can get lost during an MDS
restart and reconnect.  Reset our requested value after the MDS recovers,
so that any blocked writes will re-request a larger max_size upon waking.

Also, explicit wake session caps after the reconnect.  Normally the cap
renewal catches this, but not in the cases where the caps didn't go stale
in the first place, which would leave writers waiting on max_size asleep.
Signed-off-by: NSage Weil <sage@newdream.net>

We may first learn our fsid from any of the mon, osd, or mds maps
(whichever the monitor sends first).  Consolidate checks in a single
helper.  Initialize the client debugfs entry then, since we need the
fsid (and global_id) for the directory name.

Also remove dead mount code.
Signed-off-by: NSage Weil <sage@newdream.net>

When we open a monitor session, we send an initial AUTH message listing
the auth protocols we support, our entity name, and (possibly) a previously
assigned global_id.  The monitor chooses a protocol and responds with an
initial message.

Initially implement AUTH_NONE, a dummy protocol that provides no security,
but works within the new framework.  It generates 'authorizers' that are
used when connecting to (mds, osd) services that simply state our entity
name and global_id.

This is a wire protocol change.
Signed-off-by: NSage Weil <sage@newdream.net>

Unwind initializing if we get ENOMEM during client initialization.
Signed-off-by: NSage Weil <sage@newdream.net>

We want to ceph_con_close when we're done with the connection, before
the ref count reaches 0.  Once it does, do not call ceph_con_shutdown,
as that takes the con mutex and may sleep, and besides that is
unnecessary.
Signed-off-by: NSage Weil <sage@newdream.net>

This helps the user know what's going on during the (involved) reconnect
process.  They already see when the mds fails and reconnect starts.
Signed-off-by: NSage Weil <sage@newdream.net>

We don't get an explicit affirmative confirmation that our caps reconnect,
nor do we necessarily want to pay that cost.  So, take all this code out
for now.
Signed-off-by: NSage Weil <sage@newdream.net>

We were using the cap_gen to track both stale caps (caps that timed out
due to temporarily losing touch with the mds) and dead caps that did not
reconnect after an MDS failure.  Introduce a recon_gen counter to track
reconnections to restarted MDSs and kill dead caps based on that instead.

Rename gen to cap_gen while we're at it to make it more clear which is
which.
Signed-off-by: NSage Weil <sage@newdream.net>

This simplifies much of the error handling during mount.  It also means
that we have the mount args before client creation, and we can initialize
based on those options.
Signed-off-by: NSage Weil <sage@newdream.net>

Previously we were flushing dirty caps by passing an extra flag
when traversing the delayed caps list.  Besides being a bit ugly,
that can also miss caps that are dirty but didn't result in a
cap requeue: notably, mark_caps_dirty().

Separate the flushing into a separate helper, and traverse the
cap_dirty list.

This also brings i_dirty_item in line with i_dirty_caps: we are
on the list IFF caps != 0.  We carry an inode ref IFF
dirty_caps|flushing_caps != 0.

Lose the unused return value from __ceph_mark_caps_dirty().
Signed-off-by: NSage Weil <sage@newdream.net>

This avoids the fugly pass by reference and makes the code a bit easier
to read.
Signed-off-by: NSage Weil <sage@newdream.net>

The MDS (metadata server) client is responsible for submitting
requests to the MDS cluster and parsing the response.  We decide which
MDS to submit each request to based on cached information about the
current partition of the directory hierarchy across the cluster.  A
stateful session is opened with each MDS before we submit requests to
it, and a mutex is used to control the ordering of messages within
each session.

An MDS request may generate two responses.  The first indicates the
operation was a success and returns any result.  A second reply is
sent when the operation commits to disk.  Note that locking on the MDS
ensures that the results of updates are visible only to the updating
client before the operation commits.  Requests are linked to the
containing directory so that an fsync will wait for them to commit.

If an MDS fails and/or recovers, we resubmit requests as needed.  We
also reconnect existing capabilities to a recovering MDS to
reestablish that shared session state.  Old dentry leases are
invalidated.
Signed-off-by: NSage Weil <sage@newdream.net>