We are in a position to return an error; do that instead.
Signed-off-by: NSage Weil <sage@newdream.net>

When making a request in the virtual snapdir or a snapped portion of the
namespace, we should choose the MDS based on the first nonsnap parent (and
its caps).  If that is not the best place, we will get forward hints to
find the right MDS in the cluster.  This fixes ESTALE errors when using
the .snap directory and namespace with multiple MDSs.
Signed-off-by: NSage Weil <sage@newdream.net>

The use of a completion when waiting for session shutdown during umount is
inappropriate, given the complexity of the condition.  For multiple MDS's,
this resulted in the umount thread spinning, often preventing the session
close message from being processed in some cases.

Switch to a waitqueue and defined a condition helper.  This cleans things
up nicely.
Signed-off-by: NSage Weil <sage@newdream.net>

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

Implement flock inode operation to support advisory file locking.  All
lock/unlock operations are synchronous with the MDS.  Lock state is
sent when reconnecting to a recovering MDS to restore the shared lock
state.
Signed-off-by: NGreg Farnum <gregf@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

Encode either old or v2 encoding of client_reconnect message, depending on
whether the peer has the FLOCK feature bit.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NGreg Farnum <gregf@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

When we get a cap EXPORT message, make sure we are connected to all export
targets to ensure we can handle the matching IMPORT.
Signed-off-by: NSage Weil <sage@newdream.net>

If an MDS we are talking to may have failed, we need to open sessions to
its potential export targets to ensure that any in-progress migration that
may have involved some of our caps is properly handled.
Signed-off-by: NSage Weil <sage@newdream.net>

There are a few cases where we need to open sessions with a given mds's
potential export targets.
Signed-off-by: NSage Weil <sage@newdream.net>

Caps related accounting is now being done per mds client instead
of just being global. This prepares ground work for a later revision
of the caps preallocated reservation list.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

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

No functional change, aside from more useful debug output.
Signed-off-by: NSage Weil <sage@newdream.net>

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

This fixes an issue triggered by running concurrent syncs. One of the syncs
would go through while the other would just hang indefinitely. In any case, we
never actually want to wake a single waiter, so the *_all functions should
be used.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

Strip the cap and dentry releases from replayed messages.  They can
cause the shared state to get out of sync because they were generated
(with the request message) earlier, and no longer reflect the current
client state.
Signed-off-by: NSage Weil <sage@newdream.net>

Replayed rename operations (after an mds failure/recovery) were broken
because the request paths were regenerated from the dentry names, which
get mangled when d_move() is called.

Instead, resend the previous request message when replaying completed
operations.  Just make sure the REPLAY flag is set and the target ino is
filled in.

This fixes problems with workloads doing renames when the MDS restarts,
where the rename operation appears to succeed, but on mds restart then
fails (leading to client confusion, app breakage, etc.).
Signed-off-by: NSage Weil <sage@newdream.net>

This fixes a race between handle_reply finishing an mds request, signalling
completion, and then dropping the request structing and its dentry+inode
refs, and pre_umount function waiting for requests to finish before
letting the vfs tear down the dcache.  If umount was delayed waiting for
mds requests, we could race and BUG in shrink_dcache_for_umount_subtree
because of a slow dput.

This delays umount until the msgr queue flushes, which means handle_reply
will exit and will have dropped the ceph_mds_request struct.  I'm assuming
the VFS has already ensured that its calls have all completed and those
request refs have thus been dropped as well (I haven't seen that race, at
least).
Signed-off-by: NSage Weil <sage@newdream.net>

If we have enough memory to allocate a new cap release message, do so, so
that we can send a partial release message immediately.  This keeps us from
making the MDS wait when the cap release it needs is in a partially full
release message.

If we fail because of ENOMEM, oh well, they'll just have to wait a bit
longer.
Signed-off-by: NSage Weil <sage@newdream.net>

If we get an IMPORT that give us a cap, but we don't have the inode, queue
a release (and try to send it immediately) so that the MDS doesn't get
stuck waiting for us.
Signed-off-by: NSage Weil <sage@newdream.net>

If the client revokes a lease with a higher seq than what we have, keep
the mds's seq, so that it honors our release.  Otherwise, we can hang
indefinitely.
Signed-off-by: NSage Weil <sage@newdream.net>

If an mds request is aborted (timeout, SIGKILL), it is left registered to
keep our state in sync with the mds.  If we get a forward notification,
though, we know the request didn't succeed and we can unregister it
safely.  We were trying to resend it, but then bailing out (and not
unregistering) in __do_request.
Signed-off-by: NSage Weil <sage@newdream.net>

The lease code includes a mask in the CEPH_LOCK_* namespace, but that
namespace is changing, and only one mask (formerly _DN == 1) is used, so
hard code for that value for now.

If we ever extend this code to handle leases over different data types we
can extend it accordingly.
Signed-off-by: NSage Weil <sage@newdream.net>

The underlying problem is that many mds requests can't be restarted.  For
example, a restarted create() would return -EEXIST if the original request
succeeds.  However, we do not want a hung MDS to hang the client too.  So,
use the _killable wait_for_completion variants to abort on SIGKILL but
nothing else.
Signed-off-by: NSage Weil <sage@newdream.net>

The C99 specification states in section 6.11.5:

The placement of a storage-class specifier other than at the beginning
of the declaration specifiers in a declaration is an obsolescent
feature.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NSage Weil <sage@newdream.net>

This is essential, as for the rados block device we'll need
to run in different contexts that would need flags that
are other than GFP_NOFS.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

We invalidate I_COMPLETE and dentry leases in two places: on aborted mds
request and on request replay.  Use common helper to avoid duplicate code.
Signed-off-by: NSage Weil <sage@newdream.net>

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

The remove_session_caps() helper is called when an MDS closes out our
session (either normally, or as a result of a failed reconnect), and when
we tear down state for umount.  If we remove the last cap, and there are
no cap migrations in progress, then there is little hope of us flushing
out that data to the mds (without heroic efforts to reconnect and flush).

So, to avoid leaving inodes pinned (due to dirty state) and crashing after
umount, throw out dirty caps state and unpin the inodes.  Print a warning
to the console so we know something was lost.

NOTE: Although we drop wrbuffer refs, we don't actually mark pages clean;
maybe a truncate should be queued?
Signed-off-by: NSage Weil <sage@newdream.net>

Currently, if our session is closed (due to a timeout, or explicit close,
or whatever), we just sit there doing nothing unless/until the MDS
restarts, at which point we try to reconnect.

Change client to attempt an immediate reconnect if our session is closed.

Note that currently the MDS doesn't support this, and our attempt will
fail.  We'll get a session CLOSE, our caps and dirty cap state will be
dropped, and the client will be free to attempt to reconnect.  That's
clearly not as nice as a successful reconnect, but it at least allows us
to try to carry on, and in the future the MDS will support a reconnect
and we will fare better.
Signed-off-by: NSage Weil <sage@newdream.net>

Pass a ceph_mds_session, since the caller has it.

Remove the dead code for sending empty reconnects.  It used to be used
when the MDS contacted _us_ to solicit a reconnect, and we could reply
saying "go away, I have no session."  Now we only send reconnects based
on the mds map, and only when we do in fact have an open session.
Signed-off-by: NSage Weil <sage@newdream.net>

We used to infer reconnect success by watching the MDS state, essentially
assuming that hearing nothing meant things were ok.  That wasn't
particularly reliable.  Instead, the MDS replies with an explicit OPEN
message to indicate success.

Strictly speaking, this is a protocol change, but it is a backwards
compatible one that does not break new clients + old servers or old
clients + new servers.  At least not yet.

Drop unused @all argument from kick_requests while we're at it.
Signed-off-by: NSage Weil <sage@newdream.net>

On OPENING we shouldn't have any caps (or releases).
On CLOSING, we should wait until we succeed (and throw it all out), or
don't (and are OPEN again).
On RECONNECTING we can wait until we are OPEN.
Signed-off-by: NSage Weil <sage@newdream.net>

If the MDS restarts, the expire caps state is no longer shared, and can be
thrown out.  Caps state will be rebuilt on the MDS during the reconnect
process that follows.  Zero out any release messages and adjust the
release counter accordingly.
Signed-off-by: NSage Weil <sage@newdream.net>

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

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

We only need to pass in front_len.  Callers can attach any other payload
pieces (middle, data) as they see fit.
Signed-off-by: NSage Weil <sage@newdream.net>

Returning ERR_PTR(-ENOMEM) is useless extra work.  Return NULL on failure
instead, and fix up the callers (about half of which were wrong anyway).
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NCheng Renquan <crquan@gmail.com>
Signed-off-by: NSage Weil <sage@newdream.net>

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