- 04 11月, 2017 6 次提交
-
-
由 Christoph Hellwig 提交于
The hidden gendisks introduced in the next patch need to keep the dev field in their struct device empty so that udev won't try to create block device nodes for them. To support that rewrite disk_devt to look at the major and first_minor fields in the gendisk itself instead of looking into the struct device. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Christoph Hellwig 提交于
This helpers allows to bounce steal the uncompleted bios from a request so that they can be reissued on another path. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Christoph Hellwig 提交于
This helper allows reinserting a bio into a new queue without much overhead, but requires all queue limits to be the same for the upper and lower queues, and it does not provide any recursion preventions. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NJavier González <javier@cnexlabs.com> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Christoph Hellwig 提交于
Set aside a bit in the request/bio flags for driver use. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NHannes Reinecke <hare@suse.com> Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Christoph Hellwig 提交于
This flag should be before the operation-specific REQ_NOUNMAP bit. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NHannes Reinecke <hare@suse.com> Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
git://git.infradead.org/nvme由 Jens Axboe 提交于
Pull NVMe changes from Christoph: "Below are the currently queue nvme updates for Linux 4.15. There are a few more things that could make it for this merge window, but I'd like to get things into linux-next, especially for the unlikely case that Linus decided to cut -rc8. Highlights: - support for SGLs in the PCIe driver (Chaitanya Kulkarni) - disable I/O schedulers for the admin queue (Israel Rukshin) - various Fibre Channel fixes and enhancements (James Smart) - various refactoring for better code sharing between transports (Sagi Grimberg and me) as well as lots of little bits from various contributors."
-
- 03 11月, 2017 1 次提交
-
-
由 Minwoo Im 提交于
a tiny typo fixed in a comment. Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
- 02 11月, 2017 2 次提交
-
-
由 Arnd Bergmann 提交于
Like many storage drivers, skd uses an unsigned 32-bit number for interchanging the current time with the firmware. This will overflow in y2106 and is otherwise safe. However, the get_seconds() function is generally considered deprecated since the behavior is different between 32-bit and 64-bit architectures, and using it may indicate a bigger problem. To annotate that we've thought about this, let's add a comment here and migrate to the ktime_get_real_seconds() function that consistently returns a 64-bit number. Signed-off-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Arnd Bergmann 提交于
After the cdrom cleanup, I get randconfig warnings for some configurations: warning: (BLK_DEV_IDECD && BLK_DEV_SR) selects CDROM which has unmet direct dependencies (BLK_DEV) This adds an explicit BLK_DEV dependency for both drivers. The other drivers that select 'CDROM' already have this and don't need a change. Fixes: 2a750166 ("block: Rework drivers/cdrom/Makefile") Signed-off-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
- 01 11月, 2017 26 次提交
-
-
由 Keith Busch 提交于
Signed-off-by: NKeith Busch <keith.busch@intel.com> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 James Smart 提交于
Below is a stack trace for an issue that was reported. What's happening is that the nvmet layer had it's controller kato timeout fire, which causes it to schedule its fatal error handler via the fatal_err_work element. The error handler is invoked, which calls the transport delete_ctrl() entry point, and as the transport tears down the controller, nvmet_sq_destroy ends up doing the final put on the ctlr causing it to enter its free routine. The ctlr free routine does a cancel_work_sync() on fatal_err_work element, which then does a flush_work and wait_for_completion. But, as the wait is in the context of the work element being flushed, its in a catch-22 and the thread hangs. [ 326.903131] nvmet: ctrl 1 keep-alive timer (15 seconds) expired! [ 326.909832] nvmet: ctrl 1 fatal error occurred! [ 327.643100] lpfc 0000:04:00.0: 0:6313 NVMET Defer ctx release xri x114 flg x2 [ 494.582064] INFO: task kworker/0:2:243 blocked for more than 120 seconds. [ 494.589638] Not tainted 4.14.0-rc1.James+ #1 [ 494.594986] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 494.603718] kworker/0:2 D 0 243 2 0x80000000 [ 494.609839] Workqueue: events nvmet_fatal_error_handler [nvmet] [ 494.616447] Call Trace: [ 494.619177] __schedule+0x28d/0x890 [ 494.623070] schedule+0x36/0x80 [ 494.626571] schedule_timeout+0x1dd/0x300 [ 494.631044] ? dequeue_task_fair+0x592/0x840 [ 494.635810] ? pick_next_task_fair+0x23b/0x5c0 [ 494.640756] wait_for_completion+0x121/0x180 [ 494.645521] ? wake_up_q+0x80/0x80 [ 494.649315] flush_work+0x11d/0x1a0 [ 494.653206] ? wake_up_worker+0x30/0x30 [ 494.657484] __cancel_work_timer+0x10b/0x190 [ 494.662249] cancel_work_sync+0x10/0x20 [ 494.666525] nvmet_ctrl_put+0xa3/0x100 [nvmet] [ 494.671482] nvmet_sq_:q+0x64/0xd0 [nvmet] [ 494.676540] nvmet_fc_delete_target_queue+0x202/0x220 [nvmet_fc] [ 494.683245] nvmet_fc_delete_target_assoc+0x6d/0xc0 [nvmet_fc] [ 494.689743] nvmet_fc_delete_ctrl+0x137/0x1a0 [nvmet_fc] [ 494.695673] nvmet_fatal_error_handler+0x30/0x40 [nvmet] [ 494.701589] process_one_work+0x149/0x360 [ 494.706064] worker_thread+0x4d/0x3c0 [ 494.710148] kthread+0x109/0x140 [ 494.713751] ? rescuer_thread+0x380/0x380 [ 494.718214] ? kthread_park+0x60/0x60 Correct by having the fc transport convert to a different workq context for the actual controller teardown which may call the cancel_work_sync. Signed-off-by: NJames Smart <james.smart@broadcom.com> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 James Smart 提交于
When a remoteport is unregistered (connectivity lost), the following actions are taken: - the remoteport is marked DELETED - the time when dev_loss_tmo would expire is set in the remoteport - all controllers on the remoteport are reset. After a controller resets, it will stall in a RECONNECTING state waiting for one of the following: - the controller will continue to attempt reconnect per max_retries and reconnect_delay. As no remoteport connectivity, the reconnect attempt will immediately fail. If max reconnects has not been reached, a new reconnect_delay timer will be schedule. If the current time plus another reconnect_delay exceeds when dev_loss_tmo expires on the remote port, then the reconnect_delay will be shortend to schedule no later than when dev_loss_tmo expires. If max reconnect attempts are reached (e.g. ctrl_loss_tmo reached) or dev_loss_tmo ix exceeded without connectivity, the controller is deleted. - the remoteport is re-registered prior to dev_loss_tmo expiring. The resume of the remoteport will immediately attempt to reconnect each of its suspended controllers. Signed-off-by: NJames Smart <james.smart@broadcom.com> Reviewed-by: NHannes Reinecke <hare@suse.com> [hch: updated to use nvme_delete_ctrl] Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 James Smart 提交于
Transport will typically transition from LIVE to RESETTING when initially performing a reset or recovering from an error. Adding this transition allows a transport to transition to RECONNECTING when it checks/waits for connectivity then creates new transport connections and reinits the controller. Signed-off-by: NJames Smart <james.smart@broadcom.com> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 James Smart 提交于
Check remoteport connectivity before initiating reconnects Signed-off-by: NJames Smart <james.smart@broadcom.com> Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 James Smart 提交于
Add a dev_loss_tmo value, paralleling the SCSI FC transport, for device connectivity loss. The transport initializes the value in the nvme_fc_register_remoteport() call. If the value is not set, a default of 60s is set. Add a new routine to the api, nvme_fc_set_remoteport_devloss() routine, which allows the lldd to dynamically update the value on an existing remoteport. Signed-off-by: NJames Smart <james.smart@broadcom.com> Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 James Smart 提交于
Clean up some of the controller state checks and add the RESETTING->RECONNECTING state transition. Specifically: - the movement of the RESETTING state change and schedule of reset_work to core doesn't work wiht nvme_fc_error_recovery setting state to RECONNECTING before attempting to reset. Remove the state change as the reset request does it. - In the rare cases where an error occurs right as we're transitioning to LIVE, defer the controller start actions. - In error handling on teardown of associations while performing initial controller creation - avoid quiesce calls on the admin_q. They are unneeded. - Add the RESETTING->RECONNECTING transition in the reset handler. Signed-off-by: NJames Smart <james.smart@broadcom.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 Sagi Grimberg 提交于
Prevent racing controller reset and delete flows. reset_work must not ever self-requeue so flushing it suffices. Reported-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NSagi Grimberg <sagi@grimberg.me> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 Sagi Grimberg 提交于
instead of just queueing delete work Reported-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NSagi Grimberg <sagi@grimberg.me> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 Christoph Hellwig 提交于
No change in behavior except that the FC code cancels two work items a little later now. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NJames Smart <james.smart@broadcom.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 Christoph Hellwig 提交于
It is only used in two places, and some of the work done by it will be taken into common code soon. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 Christoph Hellwig 提交于
Move the ->delete_work and the associated helpers to common code instead of duplicating them in every driver. This also adds the missing reference get/put for the loop driver. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NJames Smart <james.smart@broadcom.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 Christoph Hellwig 提交于
No need to have two functions doing the same thing. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagi@grimberg.me> Reviewed-by: NJames Smart <james.smart@broadcom.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 James Smart 提交于
There's no need to wait for the full nvme_wq, which is now shared, to flush. flush only the delete_work item. Signed-off-by: NJames Smart <james.smart@broadcom.com> Reviewed-by: NSagi Grimberg <sgi@grimberg.me> Signed-off-by: NChristoph Hellwig <hch@lst.de>
-
由 Bart Van Assche 提交于
Instead of referring from inside drivers/cdrom/Makefile to all the drivers that use this driver, let these drivers select the cdrom driver. This change makes the cdrom build code follow the approach that is used for most other drivers, namely refer from the higher layers to the lower layer instead of from the lower layer to the higher layers. Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
SCSI restarts its queue in scsi_end_request() automatically, so we don't need to handle this case in blk-mq. Especailly any request won't be dequeued in this case, we needn't to worry about IO hang caused by restart vs. dispatch. Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
Now restart is used in the following cases, and TAG_SHARED is for SCSI only. 1) .get_budget() returns BLK_STS_RESOURCE - if resource in target/host level isn't satisfied, this SCSI device will be added in shost->starved_list, and the whole queue will be rerun (via SCSI's built-in RESTART) in scsi_end_request() after any request initiated from this host/targe is completed. Forget to mention, host level resource can't be an issue for blk-mq at all. - the same is true if resource in the queue level isn't satisfied. - if there isn't outstanding request on this queue, then SCSI's RESTART can't work(blk-mq's can't work too), and the queue will be run after SCSI_QUEUE_DELAY, and finally all starved sdevs will be handled by SCSI's RESTART when this request is finished 2) scsi_dispatch_cmd() returns BLK_STS_RESOURCE - if there isn't onprogressing request on this queue, the queue will be run after SCSI_QUEUE_DELAY - otherwise, SCSI's RESTART covers the rerun. 3) blk_mq_get_driver_tag() failed - BLK_MQ_S_TAG_WAITING covers the cross-queue RESTART for driver allocation. In one word, SCSI's built-in RESTART is enough to cover the queue rerun, and we don't need to pay special attention to TAG_SHARED wrt. restart. In my test on scsi_debug(8 luns), this patch improves IOPS by 20% ~ 30% when running I/O on these 8 luns concurrently. Aslo Roman Pen reported the current RESTART is very expensive especialy when there are lots of LUNs attached in one host, such as in his test, RESTART causes half of IOPS be cut. Fixes: https://marc.info/?l=linux-kernel&m=150832216727524&w=2 Fixes: 6d8c6c0f ("blk-mq: Restart a single queue if tag sets are shared") Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
We need to tell blk-mq to reserve resources before queuing one request, so implement these two callbacks. Then blk-mq can avoid to dequeue request too early, and IO merging can be improved a lot. Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
In the following patch, we will implement scsi_get_budget() which need to call scsi_prep_state_check() when rq isn't dequeued yet. Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
SCSI devices use host-wide tagset, and the shared driver tag space is often quite big. However, there is also a queue depth for each lun( .cmd_per_lun), which is often small, for example, on both lpfc and qla2xxx, .cmd_per_lun is just 3. So lots of requests may stay in sw queue, and we always flush all belonging to same hw queue and dispatch them all to driver. Unfortunately it is easy to cause queue busy because of the small .cmd_per_lun. Once these requests are flushed out, they have to stay in hctx->dispatch, and no bio merge can happen on these requests, and sequential IO performance is harmed. This patch introduces blk_mq_dequeue_from_ctx for dequeuing a request from a sw queue, so that we can dispatch them in scheduler's way. We can then avoid dequeueing too many requests from sw queue, since we don't flush ->dispatch completely. This patch improves dispatching from sw queue by using the .get_budget and .put_budget callbacks. Reviewed-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
For SCSI devices, there is often a per-request-queue depth, which needs to be respected before queuing one request. Currently blk-mq always dequeues the request first, then calls .queue_rq() to dispatch the request to lld. One obvious issue with this approach is that I/O merging may not be successful, because when the per-request-queue depth can't be respected, .queue_rq() has to return BLK_STS_RESOURCE, and then this request has to stay in hctx->dispatch list. This means it never gets a chance to be merged with other IO. This patch introduces .get_budget and .put_budget callback in blk_mq_ops, then we can try to get reserved budget first before dequeuing request. If the budget for queueing I/O can't be satisfied, we don't need to dequeue request at all. Hence the request can be left in the IO scheduler queue, for more merging opportunities. Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
There may be request in sw queue, and not fetched to domain queue yet, so check it in kyber_has_work(). Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
For blk-mq, we need to be able to iterate software queues starting from any queue in a round robin fashion, so introduce this helper. Reviewed-by: NOmar Sandoval <osandov@fb.com> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
So that it becomes easy to support to dispatch from sw queue in the following patch. No functional change. Reviewed-by: NBart Van Assche <bart.vanassche@wdc.com> Reviewed-by: NOmar Sandoval <osandov@fb.com> Suggested-by: Christoph Hellwig <hch@lst.de> # for simplifying dispatch logic Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Ming Lei 提交于
When the hw queue is busy, we shouldn't take requests from the scheduler queue any more, otherwise it is difficult to do IO merge. This patch fixes the awful IO performance on some SCSI devices(lpfc, qla2xxx, ...) when mq-deadline/kyber is used by not taking requests if hw queue is busy. Reviewed-by: NOmar Sandoval <osandov@fb.com> Reviewed-by: NBart Van Assche <bart.vanassche@wdc.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Scott Bauer 提交于
He is no longer working on storage. Signed-off-by: NScott Bauer <scott.bauer@intel.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
- 31 10月, 2017 5 次提交
-
-
由 Liang Chen 提交于
mutex_destroy does nothing most of time, but it's better to call it to make the code future proof and it also has some meaning for like mutex debug. As Coly pointed out in a previous review, bcache_exit() may not be able to handle all the references properly if userspace registers cache and backing devices right before bch_debug_init runs and bch_debug_init failes later. So not exposing userspace interface until everything is ready to avoid that issue. Signed-off-by: NLiang Chen <liangchen.linux@gmail.com> Reviewed-by: NMichael Lyle <mlyle@lyle.org> Reviewed-by: NColy Li <colyli@suse.de> Reviewed-by: NEric Wheeler <bcache@linux.ewheeler.net> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 tang.junhui 提交于
Currently, Cache missed IOs are identified by s->cache_miss, but actually, there are many situations that missed IOs are not assigned a value for s->cache_miss in cached_dev_cache_miss(), for example, a bypassed IO (s->iop.bypass = 1), or the cache_bio allocate failed. In these situations, it will go to out_put or out_submit, and s->cache_miss is null, which leads bch_mark_cache_accounting() to treat this IO as a hit IO. [ML: applied by 3-way merge] Signed-off-by: Ntang.junhui <tang.junhui@zte.com.cn> Reviewed-by: NMichael Lyle <mlyle@lyle.org> Reviewed-by: NColy Li <colyli@suse.de> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Tang Junhui 提交于
bucket_in_use is updated in gc thread which triggered by invalidating or writing sectors_to_gc dirty data, It's a long interval. Therefore, when we use it to compare with the threshold, it is often not timely, which leads to inaccurate judgment and often results in bucket depletion. We have send a patch before, by the means of updating bucket_in_use periodically In gc thread, which Coly thought that would lead high latency, In this patch, we add avail_nbuckets to record the count of available buckets, and we calculate bucket_in_use when alloc or free bucket in real time. [edited by ML: eliminated some whitespace errors] Signed-off-by: NTang Junhui <tang.junhui@zte.com.cn> Signed-off-by: NMichael Lyle <mlyle@lyle.org> Reviewed-by: NMichael Lyle <mlyle@lyle.org> Reviewed-by: NColy Li <colyli@suse.de> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Elena Reshetova 提交于
atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable cached_dev.count is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: NKees Cook <keescook@chromium.org> Reviewed-by: NDavid Windsor <dwindsor@gmail.com> Reviewed-by: NHans Liljestrand <ishkamiel@gmail.com> Reviewed-by: NMichael Lyle <mlyle@lyle.org> Signed-off-by: NElena Reshetova <elena.reshetova@intel.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
-
由 Coly Li 提交于
When bcache does read I/Os, for example in writeback or writethrough mode, if a read request on cache device is failed, bcache will try to recovery the request by reading from cached device. If the data on cached device is not synced with cache device, then requester will get a stale data. For critical storage system like database, providing stale data from recovery may result an application level data corruption, which is unacceptible. With this patch, for a failed read request in writeback or writethrough mode, recovery a recoverable read request only happens when cache device is clean. That is to say, all data on cached device is up to update. For other cache modes in bcache, read request will never hit cached_dev_read_error(), they don't need this patch. Please note, because cache mode can be switched arbitrarily in run time, a writethrough mode might be switched from a writeback mode. Therefore checking dc->has_data in writethrough mode still makes sense. Changelog: V4: Fix parens error pointed by Michael Lyle. v3: By response from Kent Oversteet, he thinks recovering stale data is a bug to fix, and option to permit it is unnecessary. So this version the sysfs file is removed. v2: rename sysfs entry from allow_stale_data_on_failure to allow_stale_data_on_failure, and fix the confusing commit log. v1: initial patch posted. [small change to patch comment spelling by mlyle] Signed-off-by: NColy Li <colyli@suse.de> Signed-off-by: NMichael Lyle <mlyle@lyle.org> Reported-by: NArne Wolf <awolf@lenovo.com> Reviewed-by: NMichael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Nix <nix@esperi.org.uk> Cc: Kai Krakow <hurikhan77@gmail.com> Cc: Eric Wheeler <bcache@lists.ewheeler.net> Cc: Junhui Tang <tang.junhui@zte.com.cn> Cc: stable@vger.kernel.org Signed-off-by: NJens Axboe <axboe@kernel.dk>
-