linux/include
Josh Durgin d29adb34a9 libceph: block I/O when PAUSE or FULL osd map flags are set
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 <sage@inktank.com>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
2013-12-13 09:13:29 -08:00
..
acpi Merge branch 'acpica' 2013-11-27 01:03:27 +01:00
asm-generic Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2013-11-23 16:18:25 -08:00
clocksource
crypto crypto: scatterwalk - Set the chain pointer indication bit 2013-11-28 22:16:24 +08:00
drm Merge branch 'ttm-fixes-3.13' of git://people.freedesktop.org/~thomash/linux into drm-fixes 2013-11-21 18:46:56 +10:00
dt-bindings
keys
kvm
linux libceph: block I/O when PAUSE or FULL osd map flags are set 2013-12-13 09:13:29 -08:00
math-emu
media Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2013-11-18 15:50:07 -08:00
memory
misc
net sctp: Restore 'resent' bit to avoid retransmitted chunks for RTT measurements 2013-11-28 18:29:58 -05:00
pcmcia
ras
rdma
rxrpc
scsi [SCSI] Disable WRITE SAME for RAID and virtual host adapter drivers 2013-11-29 08:48:39 +04:00
sound ASoC: dapm: Use SND_SOC_DAPM_INIT_REG_VAL in SND_SOC_DAPM_MUX 2013-11-24 13:55:41 +00:00
target target_core_alua: Store supported ALUA states 2013-11-20 11:26:37 -08:00
trace Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-12-02 10:13:09 -08:00
uapi Power management fixes for 3.13-rc3 2013-12-05 18:26:40 -08:00
video
xen
Kbuild