linux-stable.git/net/ceph, branch v3.10.41

libceph: resend all writes after the osdmap loses the full flag

2014-03-31T16:58:13+00:00

commit 9a1ea2dbff11547a8e664f143c1ffefc586a577a upstream.

With the current full handling, there is a race between osds and
clients getting the first map marked full. If the osd wins, it will
return -ENOSPC to any writes, but the client may already have writes
in flight. This results in the client getting the error and
propagating it up the stack. For rbd, the block layer turns this into
EIO, which can cause corruption in filesystems above it.

To avoid this race, osds are being changed to drop writes that came
from clients with an osdmap older than the last osdmap marked full.
In order for this to work, clients must resend all writes after they
encounter a full -> not full transition in the osdmap. osds will wait
for an updated map instead of processing a request from a client with
a newer map, so resent writes will not be dropped by the osd unless
there is another not full -> full transition.

This approach requires both osds and clients to be fixed to avoid the
race. Old clients talking to osds with this fix may hang instead of
returning EIO and potentially corrupting an fs. New clients talking to
old osds have the same behavior as before if they encounter this race.

Fixes: http://tracker.ceph.com/issues/6938

Reviewed-by: Sage Weil 
Signed-off-by: Josh Durgin 
Signed-off-by: Greg Kroah-Hartman

libceph: block I/O when PAUSE or FULL osd map flags are set

2014-03-31T16:58:12+00:00

commit d29adb34a94715174c88ca93e8aba955850c9bde upstream.

The PAUSEWR and PAUSERD flags are meant to stop the cluster from
processing writes and reads, respectively. The FULL flag is set when
the cluster determines that it is out of space, and will no longer
process writes.  PAUSEWR and PAUSERD are purely client-side settings
already implemented in userspace clients. The osd does nothing special
with these flags.

When the FULL flag is set, however, the osd responds to all writes
with -ENOSPC. For cephfs, this makes sense, but for rbd the block
layer translates this into EIO.  If a cluster goes from full to
non-full quickly, a filesystem on top of rbd will not behave well,
since some writes succeed while others get EIO.

Fix this by blocking any writes when the FULL flag is set in the osd
client. This is the same strategy used by userspace, so apply it by
default.  A follow-on patch makes this configurable.

__map_request() is called to re-target osd requests in case the
available osds changed.  Add a paused field to a ceph_osd_request, and
set it whenever an appropriate osd map flag is set.  Avoid queueing
paused requests in __map_request(), but force them to be resent if
they become unpaused.

Also subscribe to the next osd map from the monitor if any of these
flags are set, so paused requests can be unblocked as soon as
possible.

Fixes: http://tracker.ceph.com/issues/6079

Reviewed-by: Sage Weil 
Signed-off-by: Josh Durgin 
Signed-off-by: Greg Kroah-Hartman

libceph: add function to ensure notifies are complete

2014-01-09T20:24:26+00:00

commit dd935f44a40f8fb02aff2cc0df2269c92422df1c upstream.

Without a way to flush the osd client's notify workqueue, a watch
event that is unregistered could continue receiving callbacks
indefinitely.

Unregistering the event simply means no new notifies are added to the
queue, but there may still be events in the queue that will call the
watch callback for the event. If the queue is flushed after the event
is unregistered, the caller can be sure no more watch callbacks will
occur for the canceled watch.

Signed-off-by: Josh Durgin 
Reviewed-by: Sage Weil 
Reviewed-by: Alex Elder 
Signed-off-by: Greg Kroah-Hartman

libceph: create_singlethread_workqueue() doesn't return ERR_PTRs

2014-01-09T20:24:25+00:00

commit dbcae088fa660086bde6e10d63bb3c9264832d85 upstream.

create_singlethread_workqueue() returns NULL on error, and it doesn't
return ERR_PTRs.

I tweaked the error handling a little to be consistent with earlier in
the function.

Signed-off-by: Dan Carpenter 
Reviewed-by: Sage Weil 
Signed-off-by: Greg Kroah-Hartman

libceph: potential NULL dereference in ceph_osdc_handle_map()

2014-01-09T20:24:25+00:00

commit b72e19b9225d4297a18715b0998093d843d170fa upstream.

There are two places where we read "nr_maps" if both of them are set to
zero then we would hit a NULL dereference here.

Signed-off-by: Dan Carpenter 
Reviewed-by: Sage Weil 
Signed-off-by: Greg Kroah-Hartman

libceph: fix error handling in handle_reply()

2014-01-09T20:24:25+00:00

commit 1874119664dafda3ef2ed9b51b4759a9540d4a1a upstream.

We've tried to fix the error paths in this function before, but there
is still a hidden goto in the ceph_decode_need() macro which goes to the
wrong place.  We need to release the "req" and unlock a mutex before
returning.

Signed-off-by: Dan Carpenter 
Reviewed-by: Sage Weil 
Signed-off-by: Greg Kroah-Hartman

libceph: call r_unsafe_callback when unsafe reply is received

2014-01-09T20:24:25+00:00

commit 61c5d6bf7074ee32d014dcdf7698dc8c59eb712d upstream.

We can't use !req->r_sent to check if OSD request is sent for the
first time, this is because __cancel_request() zeros req->r_sent
when OSD map changes. Rather than adding a new variable to struct
ceph_osd_request to indicate if it's sent for the first time, We
can call the unsafe callback only when unsafe OSD reply is received.
If OSD's first reply is safe, just skip calling the unsafe callback.

The purpose of unsafe callback is adding unsafe request to a list,
so that fsync(2) can wait for the safe reply. fsync(2) doesn't need
to wait for a write(2) that hasn't returned yet. So it's OK to add
request to the unsafe list when the first OSD reply is received.
(ceph_sync_write() returns after receiving the first OSD reply)

Signed-off-by: Yan, Zheng 
Reviewed-by: Sage Weil 
Signed-off-by: Greg Kroah-Hartman

libceph: fix truncate size calculation

2014-01-09T20:24:25+00:00

commit ccca4e37b1a912da3db68aee826557ea66145273 upstream.

check the "not truncated yet" case

Signed-off-by: Yan, Zheng 
Reviewed-by: Sage Weil 
Signed-off-by: Greg Kroah-Hartman

libceph: fix safe completion

2014-01-09T20:24:25+00:00

commit eb845ff13a44477f8a411baedbf11d678b9daf0a upstream.

handle_reply() calls complete_request() only if the first OSD reply
has ONDISK flag.

Signed-off-by: Yan, Zheng 
Reviewed-by: Sage Weil 
Signed-off-by: Greg Kroah-Hartman

libceph: add lingering request reference when registered

2014-01-09T20:24:24+00:00

commit 96e4dac66f69d28af2b736e723364efbbdf9fdee upstream.

When an osd request is set to linger, the osd client holds onto the
request so it can be re-submitted following certain osd map changes.
The osd client holds a reference to the request until it is
unregistered.  This is used by rbd for watch requests.

Currently, the reference is taken when the request is marked with
the linger flag.  This means that if an error occurs after that
time but before the the request completes successfully, that
reference is leaked.

There's really no reason to take the reference until the request is
registered in the the osd client's list of lingering requests, and
that only happens when the lingering (watch) request completes
successfully.

So take that reference only when it gets registered following
succesful completion, and drop it (as before) when the request
gets unregistered.  This avoids the reference problem on error
in rbd.

Rearrange ceph_osdc_unregister_linger_request() to avoid using
the request pointer after it may have been freed.

And hold an extra reference in kick_requests() while handling
a linger request that has not yet been registered, to ensure
it doesn't go away.

This resolves:
    http://tracker.ceph.com/issues/3859

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin 
Signed-off-by: Greg Kroah-Hartman