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* Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds2016-12-243-3/+3
| | | | | | | | | | | | | This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2016-12-231-0/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull final vfs updates from Al Viro: "Assorted cleanups and fixes all over the place" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: sg_write()/bsg_write() is not fit to be called under KERNEL_DS ufs: fix function declaration for ufs_truncate_blocks fs: exec: apply CLOEXEC before changing dumpable task flags seq_file: reset iterator to first record for zero offset vfs: fix isize/pos/len checks for reflink & dedupe [iov_iter] fix iterate_all_kinds() on empty iterators move aio compat to fs/aio.c reorganize do_make_slave() clone_private_mount() doesn't need to touch namespace_sem remove a bogus claim about namespace_sem being held by callers of mnt_alloc_id()
| * sg_write()/bsg_write() is not fit to be called under KERNEL_DSAl Viro2016-12-221-0/+3
| | | | | | | | | | | | | | | | | | | | Both damn things interpret userland pointers embedded into the payload; worse, they are actually traversing those. Leaving aside the bad API design, this is very much _not_ safe to call with KERNEL_DS. Bail out early if that happens. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | block: check partition alignmentStefan Haberland2016-12-191-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Partitions that are not aligned to the blocksize of a device may cause invalid I/O requests because the blocklayer cares only about alignment within the partition when building requests on partitions. device |--------4096--------|--------4096--------|--------4096--------| partition offset 512byte |-512-|--------4096--------|--------4096--------|--------4096--------| When reading/writing one 4k block of the partition this maps to reading/writing with an offset of 512 byte of the device leading to unaligned requests for the device which in turn may cause unexpected behavior of the device driver. For DASD devices we have to translate the block number into a cylinder, head, record format. The unaligned requests lead to wrong calculation and therefore to misdirected I/O. In a "good" case this leads to I/O errors because the underlying hardware detects the wrong addressing. In a worst case scenario this might destroy data on the device. To prevent partitions that are not aligned to the physical blocksize of a device check for the alignment in the blkpg_ioctl. Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* | block: allow WRITE_SAME commands with the SG_IO ioctlMauricio Faria de Oliveira2016-12-191-0/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The WRITE_SAME commands are not present in the blk_default_cmd_filter write_ok list, and thus are failed with -EPERM when the SG_IO ioctl() is executed without CAP_SYS_RAWIO capability (e.g., unprivileged users). [ sg_io() -> blk_fill_sghdr_rq() > blk_verify_command() -> -EPERM ] The problem can be reproduced with the sg_write_same command # sg_write_same --num 1 --xferlen 512 /dev/sda # # capsh --drop=cap_sys_rawio -- -c \ 'sg_write_same --num 1 --xferlen 512 /dev/sda' Write same: pass through os error: Operation not permitted # For comparison, the WRITE_VERIFY command does not observe this problem, since it is in that list: # capsh --drop=cap_sys_rawio -- -c \ 'sg_write_verify --num 1 --ilen 512 --lba 0 /dev/sda' # So, this patch adds the WRITE_SAME commands to the list, in order for the SG_IO ioctl to finish successfully: # capsh --drop=cap_sys_rawio -- -c \ 'sg_write_same --num 1 --xferlen 512 /dev/sda' # That case happens to be exercised by QEMU KVM guests with 'scsi-block' devices (qemu "-device scsi-block" [1], libvirt "<disk type='block' device='lun'>" [2]), which employs the SG_IO ioctl() and runs as an unprivileged user (libvirt-qemu). In that scenario, when a filesystem (e.g., ext4) performs its zero-out calls, which are translated to write-same calls in the guest kernel, and then into SG_IO ioctls to the host kernel, SCSI I/O errors may be observed in the guest: [...] sd 0:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [...] sd 0:0:0:0: [sda] tag#0 Sense Key : Aborted Command [current] [...] sd 0:0:0:0: [sda] tag#0 Add. Sense: I/O process terminated [...] sd 0:0:0:0: [sda] tag#0 CDB: Write Same(10) 41 00 01 04 e0 78 00 00 08 00 [...] blk_update_request: I/O error, dev sda, sector 17096824 Links: [1] http://git.qemu.org/?p=qemu.git;a=commit;h=336a6915bc7089fb20fea4ba99972ad9a97c5f52 [2] https://libvirt.org/formatdomain.html#elementsDisks (see 'disk' -> 'device') Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by: Brahadambal Srinivasan <latha@linux.vnet.ibm.com> Reported-by: Manjunatha H R <manjuhr1@in.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds2016-12-141-8/+24
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block IO fixes from Jens Axboe: "A few fixes that I collected as post-merge. I was going to wait a bit with sending this out, but the O_DIRECT fix should really go in sooner rather than later" * 'for-linus' of git://git.kernel.dk/linux-block: blk-mq: Fix failed allocation path when mapping queues blk-mq: Avoid memory reclaim when remapping queues block_dev: don't update file access position for sync direct IO nvme/pci: Log PCI_STATUS when the controller dies block_dev: don't test bdev->bd_contains when it is not stable
| * blk-mq: Fix failed allocation path when mapping queuesGabriel Krisman Bertazi2016-12-141-5/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In blk_mq_map_swqueue, there is a memory optimization that frees the tags of a queue that has gone unmapped. Later, if that hctx is remapped after another topology change, the tags need to be reallocated. If this allocation fails, a simple WARN_ON triggers, but the block layer ends up with an active hctx without any corresponding set of tags. Then, any income IO to that hctx can trigger an Oops. I can reproduce it consistently by running IO, flipping CPUs on and off and eventually injecting a memory allocation failure in that path. In the fix below, if the system experiences a failed allocation of any hctx's tags, we remap all the ctxs of that queue to the hctx_0, which should always keep it's tags. There is a minor performance hit, since our mapping just got worse after the error path, but this is the simplest solution to handle this error path. The performance hit will disappear after another successful remap. I considered dropping the memory optimization all together, but it seemed a bad trade-off to handle this very specific error case. This should apply cleanly on top of Jens' for-next branch. The Oops is the one below: SP (3fff935ce4d0) is in userspace 1:mon> e cpu 0x1: Vector: 300 (Data Access) at [c000000fe99eb110] pc: c0000000005e868c: __sbitmap_queue_get+0x2c/0x180 lr: c000000000575328: __bt_get+0x48/0xd0 sp: c000000fe99eb390 msr: 900000010280b033 dar: 28 dsisr: 40000000 current = 0xc000000fe9966800 paca = 0xc000000007e80300 softe: 0 irq_happened: 0x01 pid = 11035, comm = aio-stress Linux version 4.8.0-rc6+ (root@bean) (gcc version 5.4.0 20160609 (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.2) ) #3 SMP Mon Oct 10 20:16:53 CDT 2016 1:mon> s [c000000fe99eb3d0] c000000000575328 __bt_get+0x48/0xd0 [c000000fe99eb400] c000000000575838 bt_get.isra.1+0x78/0x2d0 [c000000fe99eb480] c000000000575cb4 blk_mq_get_tag+0x44/0x100 [c000000fe99eb4b0] c00000000056f6f4 __blk_mq_alloc_request+0x44/0x220 [c000000fe99eb500] c000000000570050 blk_mq_map_request+0x100/0x1f0 [c000000fe99eb580] c000000000574650 blk_mq_make_request+0xf0/0x540 [c000000fe99eb640] c000000000561c44 generic_make_request+0x144/0x230 [c000000fe99eb690] c000000000561e00 submit_bio+0xd0/0x200 [c000000fe99eb740] c0000000003ef740 ext4_io_submit+0x90/0xb0 [c000000fe99eb770] c0000000003e95d8 ext4_writepages+0x588/0xdd0 [c000000fe99eb910] c00000000025a9f0 do_writepages+0x60/0xc0 [c000000fe99eb940] c000000000246c88 __filemap_fdatawrite_range+0xf8/0x180 [c000000fe99eb9e0] c000000000246f90 filemap_write_and_wait_range+0x70/0xf0 [c000000fe99eba20] c0000000003dd844 ext4_sync_file+0x214/0x540 [c000000fe99eba80] c000000000364718 vfs_fsync_range+0x78/0x130 [c000000fe99ebad0] c0000000003dd46c ext4_file_write_iter+0x35c/0x430 [c000000fe99ebb90] c00000000038c280 aio_run_iocb+0x3b0/0x450 [c000000fe99ebce0] c00000000038dc28 do_io_submit+0x368/0x730 [c000000fe99ebe30] c000000000009404 system_call+0x38/0xec Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> Cc: Brian King <brking@linux.vnet.ibm.com> Cc: Douglas Miller <dougmill@linux.vnet.ibm.com> Cc: linux-block@vger.kernel.org Cc: linux-scsi@vger.kernel.org Reviewed-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * blk-mq: Avoid memory reclaim when remapping queuesGabriel Krisman Bertazi2016-12-141-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While stressing memory and IO at the same time we changed SMT settings, we were able to consistently trigger deadlocks in the mm system, which froze the entire machine. I think that under memory stress conditions, the large allocations performed by blk_mq_init_rq_map may trigger a reclaim, which stalls waiting on the block layer remmaping completion, thus deadlocking the system. The trace below was collected after the machine stalled, waiting for the hotplug event completion. The simplest fix for this is to make allocations in this path non-reclaimable, with GFP_NOIO. With this patch, We couldn't hit the issue anymore. This should apply on top of Jens's for-next branch cleanly. Changes since v1: - Use GFP_NOIO instead of GFP_NOWAIT. Call Trace: [c000000f0160aaf0] [c000000f0160ab50] 0xc000000f0160ab50 (unreliable) [c000000f0160acc0] [c000000000016624] __switch_to+0x2e4/0x430 [c000000f0160ad20] [c000000000b1a880] __schedule+0x310/0x9b0 [c000000f0160ae00] [c000000000b1af68] schedule+0x48/0xc0 [c000000f0160ae30] [c000000000b1b4b0] schedule_preempt_disabled+0x20/0x30 [c000000f0160ae50] [c000000000b1d4fc] __mutex_lock_slowpath+0xec/0x1f0 [c000000f0160aed0] [c000000000b1d678] mutex_lock+0x78/0xa0 [c000000f0160af00] [d000000019413cac] xfs_reclaim_inodes_ag+0x33c/0x380 [xfs] [c000000f0160b0b0] [d000000019415164] xfs_reclaim_inodes_nr+0x54/0x70 [xfs] [c000000f0160b0f0] [d0000000194297f8] xfs_fs_free_cached_objects+0x38/0x60 [xfs] [c000000f0160b120] [c0000000003172c8] super_cache_scan+0x1f8/0x210 [c000000f0160b190] [c00000000026301c] shrink_slab.part.13+0x21c/0x4c0 [c000000f0160b2d0] [c000000000268088] shrink_zone+0x2d8/0x3c0 [c000000f0160b380] [c00000000026834c] do_try_to_free_pages+0x1dc/0x520 [c000000f0160b450] [c00000000026876c] try_to_free_pages+0xdc/0x250 [c000000f0160b4e0] [c000000000251978] __alloc_pages_nodemask+0x868/0x10d0 [c000000f0160b6f0] [c000000000567030] blk_mq_init_rq_map+0x160/0x380 [c000000f0160b7a0] [c00000000056758c] blk_mq_map_swqueue+0x33c/0x360 [c000000f0160b820] [c000000000567904] blk_mq_queue_reinit+0x64/0xb0 [c000000f0160b850] [c00000000056a16c] blk_mq_queue_reinit_notify+0x19c/0x250 [c000000f0160b8a0] [c0000000000f5d38] notifier_call_chain+0x98/0x100 [c000000f0160b8f0] [c0000000000c5fb0] __cpu_notify+0x70/0xe0 [c000000f0160b930] [c0000000000c63c4] notify_prepare+0x44/0xb0 [c000000f0160b9b0] [c0000000000c52f4] cpuhp_invoke_callback+0x84/0x250 [c000000f0160ba10] [c0000000000c570c] cpuhp_up_callbacks+0x5c/0x120 [c000000f0160ba60] [c0000000000c7cb8] _cpu_up+0xf8/0x1d0 [c000000f0160bac0] [c0000000000c7eb0] do_cpu_up+0x120/0x150 [c000000f0160bb40] [c0000000006fe024] cpu_subsys_online+0x64/0xe0 [c000000f0160bb90] [c0000000006f5124] device_online+0xb4/0x120 [c000000f0160bbd0] [c0000000006f5244] online_store+0xb4/0xc0 [c000000f0160bc20] [c0000000006f0a68] dev_attr_store+0x68/0xa0 [c000000f0160bc60] [c0000000003ccc30] sysfs_kf_write+0x80/0xb0 [c000000f0160bca0] [c0000000003cbabc] kernfs_fop_write+0x17c/0x250 [c000000f0160bcf0] [c00000000030fe6c] __vfs_write+0x6c/0x1e0 [c000000f0160bd90] [c000000000311490] vfs_write+0xd0/0x270 [c000000f0160bde0] [c0000000003131fc] SyS_write+0x6c/0x110 [c000000f0160be30] [c000000000009204] system_call+0x38/0xec Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> Cc: Brian King <brking@linux.vnet.ibm.com> Cc: Douglas Miller <dougmill@linux.vnet.ibm.com> Cc: linux-block@vger.kernel.org Cc: linux-scsi@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
* | Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds2016-12-143-4/+21
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull SCSI updates from James Bottomley: "This update includes the usual round of major driver updates (ncr5380, lpfc, hisi_sas, megaraid_sas, ufs, ibmvscsis, mpt3sas). There's also an assortment of minor fixes, mostly in error legs or other not very user visible stuff. The major change is the pci_alloc_irq_vectors replacement for the old pci_msix_.. calls; this effectively makes IRQ mapping generic for the drivers and allows blk_mq to use the information" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (256 commits) scsi: qla4xxx: switch to pci_alloc_irq_vectors scsi: hisi_sas: support deferred probe for v2 hw scsi: megaraid_sas: switch to pci_alloc_irq_vectors scsi: scsi_devinfo: remove synchronous ALUA for NETAPP devices scsi: be2iscsi: set errno on error path scsi: be2iscsi: set errno on error path scsi: hpsa: fallback to use legacy REPORT PHYS command scsi: scsi_dh_alua: Fix RCU annotations scsi: hpsa: use %phN for short hex dumps scsi: hisi_sas: fix free'ing in probe and remove scsi: isci: switch to pci_alloc_irq_vectors scsi: ipr: Fix runaway IRQs when falling back from MSI to LSI scsi: dpt_i2o: double free on error path scsi: cxlflash: Migrate scsi command pointer to AFU command scsi: cxlflash: Migrate IOARRIN specific routines to function pointers scsi: cxlflash: Cleanup queuecommand() scsi: cxlflash: Cleanup send_tmf() scsi: cxlflash: Remove AFU command lock scsi: cxlflash: Wait for active AFU commands to timeout upon tear down scsi: cxlflash: Remove private command pool ...
| * scsi: fc: move FC transport's bsg code to bsg-libJohannes Thumshirn2016-11-171-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that all conversions are done, move the FibreChannel bsg code over to the bsg library. This patch is derived from work done by Mike Christie in 2011 [1] but only the iscsi parts got merged back then. [1] http://marc.info/?l=linux-scsi&m=131149780921009&w=2 Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| * block: add bsg_job_put() and bsg_job_get()Johannes Thumshirn2016-11-171-3/+14
| | | | | | | | | | | | | | | | | | Add bsg_job_put() and bsg_job_get() so don't need to export bsg_destroy_job() any more. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| * scsi: fc: use bsg_softirq_doneJohannes Thumshirn2016-11-171-1/+2
| | | | | | | | | | | | | | | | | | bsg_softirq_done() and fc_bsg_softirq_done() are copies of each other, so ditch the fc specific one. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| * scsi: fc: Use bsg_destroy_jobJohannes Thumshirn2016-11-171-2/+5
| | | | | | | | | | | | | | | | | | | | fc_destroy_bsgjob() and bsg_destroy_job() are now 1:1 copies, so use the latter. As bsg_destroy_job() comes from bsg-lib we need to select it in Kconfig once CONFOG_SCSI_FC_ATTRS is active. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| * block: add reference counting for struct bsg_jobJohannes Thumshirn2016-11-171-2/+5
| | | | | | | | | | | | | | | | | | Add reference counting to 'struct bsg_job' so we can implement a reuqest timeout handler for bsg_jobs, which is needed for Fibre Channel. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| * blk-mq: export blk_mq_map_queuesChristoph Hellwig2016-11-082-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | This will allow SCSI to have a single blk_mq_ops structure that either lets the LLDD map the queues to PCIe MSIx vectors or use the default. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
* | Merge branch 'for-4.10' of ↵Linus Torvalds2016-12-131-1/+3
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata Pull libata updates from Tejun Heo: - Adam added opt-in ATA command priority support. - There are machines which hide multiple nvme devices behind an ahci BAR. Dan Williams proposed a solution to force-switch the mode but deemed too hackishd. People are gonna discuss the proper way to handle the situation in nvme standard meetings. For now, detect and warn about the situation. - Low level driver specific changes. Christoph Hellwig pipes in about the hidden nvme warning: "I wish that was the case. We've pretty much agreed that we'll want to implement it as a virtual PCIe root bridge, similar to Intels other 'innovation' VMD that we work around that way. But Intel management has apparently decided that they don't want to spend more cycles on this now that Lenovo has an optional BIOS that doesn't force this broken mode anymore, and no one outside of Intel has enough information to implement something like this. So for now I guess this warning is it, until Intel reconsideres and spends resources on fixing up the damage their Chipset people caused" * 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata: ahci: warn about remapped NVMe devices ahci-remap.h: add ahci remapping definitions nvme: move NVMe class code to pci_ids.h pata: imx: support controller modes up to PIO4 pata: imx: add support of setting timings for PIO modes pata: imx: set controller PIO mode with .set_piomode callback pata: imx: sort headers out ata: set ncq_prio_enabled iff device has support ata: ATA Command Priority Disabled By Default ata: Enabling ATA Command Priorities block: Add iocontext priority to request ahci: qoriq: added ls1046a platform support
| * | block: Add iocontext priority to requestAdam Manzanares2016-10-191-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch adds an association between iocontext ioprio and the ioprio of a request. This is done to enable request based drivers the ability to act on priority information stored in the request. An example being ATA devices that support command priorities. If the ATA driver discovers that the device supports command priorities and the request has valid priority information indicating the request is high priority, then a high priority command can be sent to the device. This should improve tail latencies for high priority IO on any device that queues requests internally and can make use of the priority information stored in the request. The ioprio of the request is set in blk_rq_set_prio which takes the request and the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the iopriority of the request is set as the iopriority of the ioc. In init_request_from_bio a check is made to see if the ioprio of the bio is valid and if so then the request prio comes from the bio. Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Tejun Heo <tj@kernel.org>
* | | Merge branch 'for-4.10/block' of git://git.kernel.dk/linux-blockLinus Torvalds2016-12-1330-488/+2835
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block layer updates from Jens Axboe: "This is the main block pull request this series. Contrary to previous release, I've kept the core and driver changes in the same branch. We always ended up having dependencies between the two for obvious reasons, so makes more sense to keep them together. That said, I'll probably try and keep more topical branches going forward, especially for cycles that end up being as busy as this one. The major parts of this pull request is: - Improved support for O_DIRECT on block devices, with a small private implementation instead of using the pig that is fs/direct-io.c. From Christoph. - Request completion tracking in a scalable fashion. This is utilized by two components in this pull, the new hybrid polling and the writeback queue throttling code. - Improved support for polling with O_DIRECT, adding a hybrid mode that combines pure polling with an initial sleep. From me. - Support for automatic throttling of writeback queues on the block side. This uses feedback from the device completion latencies to scale the queue on the block side up or down. From me. - Support from SMR drives in the block layer and for SD. From Hannes and Shaun. - Multi-connection support for nbd. From Josef. - Cleanup of request and bio flags, so we have a clear split between which are bio (or rq) private, and which ones are shared. From Christoph. - A set of patches from Bart, that improve how we handle queue stopping and starting in blk-mq. - Support for WRITE_ZEROES from Chaitanya. - Lightnvm updates from Javier/Matias. - Supoort for FC for the nvme-over-fabrics code. From James Smart. - A bunch of fixes from a whole slew of people, too many to name here" * 'for-4.10/block' of git://git.kernel.dk/linux-block: (182 commits) blk-stat: fix a few cases of missing batch flushing blk-flush: run the queue when inserting blk-mq flush elevator: make the rqhash helpers exported blk-mq: abstract out blk_mq_dispatch_rq_list() helper blk-mq: add blk_mq_start_stopped_hw_queue() block: improve handling of the magic discard payload blk-wbt: don't throttle discard or write zeroes nbd: use dev_err_ratelimited in io path nbd: reset the setup task for NBD_CLEAR_SOCK nvme-fabrics: Add FC LLDD loopback driver to test FC-NVME nvme-fabrics: Add target support for FC transport nvme-fabrics: Add host support for FC transport nvme-fabrics: Add FC transport LLDD api definitions nvme-fabrics: Add FC transport FC-NVME definitions nvme-fabrics: Add FC transport error codes to nvme.h Add type 0x28 NVME type code to scsi fc headers nvme-fabrics: patch target code in prep for FC transport support nvme-fabrics: set sqe.command_id in core not transports parser: add u64 number parser nvme-rdma: align to generic ib_event logging helper ...
| * | | blk-stat: fix a few cases of missing batch flushingJens Axboe2016-12-091-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Everytime we need to read ->nr_samples, we should have flushed the batch first. The non-mq read path also needs to flush the batch. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-flush: run the queue when inserting blk-mq flushJens Axboe2016-12-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we pass in to run the queue async, but don't flag the queue to be run. We don't need to run it async here, but we should run it. So fixup the parameters. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com>
| * | | elevator: make the rqhash helpers exportedJens Axboe2016-12-091-4/+4
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com>
| * | | blk-mq: abstract out blk_mq_dispatch_rq_list() helperJens Axboe2016-12-092-38/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Takes a list of requests, and dispatches it. Moves any residual requests to the dispatch list. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com>
| * | | blk-mq: add blk_mq_start_stopped_hw_queue()Jens Axboe2016-12-091-7/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a variant for all hardware queues, but not one for a single hardware queue. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com>
| * | | block: improve handling of the magic discard payloadChristoph Hellwig2016-12-094-78/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of allocating a single unused biovec for discard requests, send them down without any payload. Instead we allow the driver to add a "special" payload using a biovec embedded into struct request (unioned over other fields never used while in the driver), and overloading the number of segments for this case. This has a couple of advantages: - we don't have to allocate the bio_vec - the amount of special casing for discard requests in the block layer is significantly reduced - using this same scheme for other request types is trivial, which will be important for implementing the new WRITE_ZEROES op on devices where it actually requires a payload (e.g. SCSI) - we can get rid of playing games with the request length, as we'll never touch it and completions will work just fine - it will allow us to support ranged discard operations in the future by merging non-contiguous discard bios into a single request - last but not least it removes a lot of code This patch is the common base for my WIP series for ranges discards and to remove discard_zeroes_data in favor of always using REQ_OP_WRITE_ZEROES, so it would be good to get it in quickly. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-wbt: don't throttle discard or write zeroesChristoph Hellwig2016-12-091-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Both of these are metadata only commands that are not issued by the writeback code and not directly relevant to the writeback bandwith. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-mq: blk_account_io_start() takes a boolJens Axboe2016-12-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
| * | | block: fix unintended fallthrough in generic_make_request_checks()Nicolai Stange2016-12-051-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit e73c23ff736e ("block: add async variant of blkdev_issue_zeroout") messages like the following show up: EXT4-fs (dm-1): Delayed block allocation failed for inode 2368848 at logical offset 0 with max blocks 1 with error 95 EXT4-fs (dm-1): This should not happen!! Data will be lost Due to the following fallthrough introduced with commit 2d253440b5af ("block: Define zoned block device operations"), generic_make_request_checks() would accept a REQ_OP_WRITE_SAME bio only if the block device supports "write same" *and* is a zoned one: switch (bio_op(bio)) { [...] case REQ_OP_WRITE_SAME: if (!bdev_write_same(bio->bi_bdev)) goto not_supported; case REQ_OP_ZONE_REPORT: case REQ_OP_ZONE_RESET: if (!bdev_is_zoned(bio->bi_bdev)) goto not_supported; break; [...] } Thus, although the bio setup as done by __blkdev_issue_write_same() from commit e73c23ff736e ("block: add async variant of blkdev_issue_zeroout") would succeed, its actual submission would not, resulting in the EOPNOTSUPP == 95. Fix this by removing the fallthrough which, due to the lack of an explicit comment, seems to be unintended anyway. Fixes: e73c23ff736e ("block: add async variant of blkdev_issue_zeroout") Fixes: 2d253440b5af ("block: Define zoned block device operations") Signed-off-by: Nicolai Stange <nicstange@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-stat: fix a typoShaohua Li2016-12-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Shaohua Li <shli@fb.com> Fixes: cf43e6be865a ("block: add scalable completion tracking of requests") Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: factor out req_set_nomergeRitesh Harjani2016-12-011-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Factor out common code for setting REQ_NOMERGE flag which is being used out at certain places and make it a helper instead, req_set_nomerge(). Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org> Get rid of the inline. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: add support for REQ_OP_WRITE_ZEROESChaitanya Kulkarni2016-12-017-8/+105
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a new block layer operation to zero out a range of LBAs. This allows to implement zeroing for devices that don't use either discard with a predictable zero pattern or WRITE SAME of zeroes. The prominent example of that is NVMe with the Write Zeroes command, but in the future, this should also help with improving the way zeroing discards work. For this operation, suitable entry is exported in sysfs which indicate the number of maximum bytes allowed in one write zeroes operation by the device. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: add async variant of blkdev_issue_zerooutChaitanya Kulkarni2016-12-011-34/+81
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Similar to __blkdev_issue_discard this variant allows submitting the final bio asynchronously and chaining multiple ranges into a single completion. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: Check partition alignment on zoned block devicesDamien Le Moal2016-12-011-0/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Both blkdev_report_zones and blkdev_reset_zones can operate on a partition of a zoned block device. However, the first and last zones reported for a partition make sense only if the partition start sector and size are aligned on the device zone size. The same applies for zone reset. Resetting the first or the last zone of a partition straddling zones may impact neighboring partitions. Finally, if a partition start sector is not at the beginning of a sequential zone, it will be impossible to write to the first sectors of the partition on a host-managed device. Avoid all these problems and incoherencies by ignoring partitions that are not zone aligned. Note: Even with CONFIG_BLK_DEV_ZONED disabled, bdev_is_zoned() will report the correct disk zoning type (host-aware, host-managed or none) but bdev_zone_size() will always return 0 for zoned block devices (i.e. the zone size is unknown). So test this as a way to ensure that a zoned block device is being handled as such. As a result, for a host-aware devices, unaligned zone partitions will be accepted with CONFIG_BLK_DEV_ZONED disabled. That is, the disk will be treated as a regular block device (as it should). If zoned block device support is enabled, only aligned partitions will be accepted. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-mq: Drop explicit timeout sync in hotplugGabriel Krisman Bertazi2016-11-291-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After commit 287922eb0b18 ("block: defer timeouts to a workqueue"), deleting the timeout work after freezing the queue shouldn't be necessary, since the synchronization is already enforced by the acquisition of a q_usage_counter reference in blk_mq_timeout_work. Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> Reviewed-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-wbt: allow wbt to be enabled always through sysfsJens Axboe2016-11-283-7/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently there's no way to enable wbt if it's not enabled in the kernel config by default for a device. Allow a write to the 'wbt_lat_usec' queue sysfs file to enable wbt. This is useful for both the kernel config case, but also if the device is CFQ managed and it was turned off by default. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-wbt: cleanup disable-by-default for CFQJens Axboe2016-11-283-10/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make it clear that we are disabling wbt for the specified queued, if it was enabled by default. This is in preparation for allowing users to re-enable wbt, and not have it disabled automatically again. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-wbt: allow reset of default latency through sysfsJens Axboe2016-11-283-11/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow a write of '-1' to reset the default latency target for a given device. This removes knowledge of the different default settings for rotational vs non-rotational from user space. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcgTejun Heo2016-11-222-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blkcg allocates some per-cgroup data structures with GFP_NOWAIT and when that fails falls back to operations which aren't specific to the cgroup. Occassional failures are expected under pressure and falling back to non-cgroup operation is the right thing to do. Unfortunately, I forgot to add __GFP_NOWARN to these allocations and these expected failures end up creating a lot of noise. Add __GFP_NOWARN. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Marc MERLIN <marc@merlins.org> Reported-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: bio: pass bvec table to bio_init()Ming Lei2016-11-221-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some drivers often use external bvec table, so introduce this helper for this case. It is always safe to access the bio->bi_io_vec in this way for this case. After converting to this usage, it will becomes a bit easier to evaluate the remaining direct access to bio->bi_io_vec, so it can help to prepare for the following multipage bvec support. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Fixed up the new O_DIRECT cases. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: apply blk_partition_remap to REQ_OP_ZONE_RESETShaun Tancheff2016-11-211-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a ZBC device is partitioned and operations are performed on the partition the zone information is rebased to the partition, however the zone reset is not mapped from the partition to device as are other operations. This causes the API (report zones / reset zone) to be unbalanced in this regard. Checking for the zone reset op code explicitly will balance the API. Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-mq: make the polling code adaptiveJens Axboe2016-11-172-11/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous commit introduced the hybrid sleep/poll mode. Take that one step further, and use the completion latencies to automatically sleep for half the mean completion time. This is a good approximation. This changes the 'io_poll_delay' sysfs file a bit to expose the various options. Depending on the value, the polling code will behave differently: -1 Never enter hybrid sleep mode 0 Use half of the completion mean for the sleep delay >0 Use this specific value as the sleep delay Signed-off-by: Jens Axboe <axboe@fb.com> Tested-By: Stephen Bates <sbates@raithlin.com> Reviewed-By: Stephen Bates <sbates@raithlin.com>
| * | | blk-mq: implement hybrid poll mode for sync O_DIRECTJens Axboe2016-11-173-0/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch enables a hybrid polling mode. Instead of polling after IO submission, we can induce an artificial delay, and then poll after that. For example, if the IO is presumed to complete in 8 usecs from now, we can sleep for 4 usecs, wake up, and then do our polling. This still puts a sleep/wakeup cycle in the IO path, but instead of the wakeup happening after the IO has completed, it'll happen before. With this hybrid scheme, we can achieve big latency reductions while still using the same (or less) amount of CPU. Signed-off-by: Jens Axboe <axboe@fb.com> Tested-By: Stephen Bates <sbates@raithlin.com> Reviewed-By: Stephen Bates <sbates@raithlin.com>
| * | | blk-wbt: fix old-style function declarationArnd Bergmann2016-11-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The newly added driver causes a harmless warning in some configurations: block/blk-wbt.c:250:1: error: ‘inline’ is not at beginning of declaration [-Werror=old-style-declaration] static bool inline stat_sample_valid(struct blk_rq_stat *stat) This makes it use the expected format for the declaration. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: deal with stale req count of plug listMing Lei2016-11-162-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In both legacy and mq path, req count of plug list is computed before allocating request, so the number can be stale when falling back to slept allocation, also the new introduced wbt can sleep too. This patch deals with the case by checking if plug list becomes empty, and fixes the KASAN report of 'BUG: KASAN: stack-out-of-bounds' which is introduced by Shaohua's patches of dispatching big request. Fixes: 600271d900002(blk-mq: immediately dispatch big size request) Fixes: 50d24c34403c6(block: immediately dispatch big size request) Cc: Shaohua Li <shli@fb.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | bsg: Add sparse annotations to bsg_request_fn()Bart Van Assche2016-11-141-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid that sparse complains about unbalanced lock actions. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-wbt: use BLK_STAT_{READ,WRITE} instead of 0/1Jens Axboe2016-11-111-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | Since we have proper enums for the stats directions, use them. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-wbt: remove stat opsJens Axboe2016-11-113-43/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Again a leftover from when the throttling code was generic. Now that we just have the block user, get rid of the stat ops and indirections. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-wbt: store queue instead of bdiJens Axboe2016-11-112-11/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The bdi was a leftover from when the code was block layer agnostic. Now that we just support a block layer user, store the queue directly. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: move poll code to blk-mqJens Axboe2016-11-112-46/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The poll code is blk-mq specific, let's move it to blk-mq.c. This is a prep patch for improving the polling code. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | blk-mq: blk_mq_try_issue_directly() should lookup hardware queueJens Axboe2016-11-111-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A previous commit changed this to pass in the hardware queue, but it was using the wrong hardware queue. Hence a request that was allocated on one hardware queue ended up being issued on another one, and that caused IO timeouts and oopses on some drivers. Since the request holds hardware queue private resources, like a tag, we can't just issue it on a different hardware queue. Fixes: 2253efc850c4 ("blk-mq: Move more code into blk_mq_direct_issue_request()") Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: hook up writeback throttlingJens Axboe2016-11-106-4/+171
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable throttling of buffered writeback to make it a lot more smooth, and has way less impact on other system activity. Background writeback should be, by definition, background activity. The fact that we flush huge bundles of it at the time means that it potentially has heavy impacts on foreground workloads, which isn't ideal. We can't easily limit the sizes of writes that we do, since that would impact file system layout in the presence of delayed allocation. So just throttle back buffered writeback, unless someone is waiting for it. The algorithm for when to throttle takes its inspiration in the CoDel networking scheduling algorithm. Like CoDel, blk-wb monitors the minimum latencies of requests over a window of time. In that window of time, if the minimum latency of any request exceeds a given target, then a scale count is incremented and the queue depth is shrunk. The next monitoring window is shrunk accordingly. Unlike CoDel, if we hit a window that exhibits good behavior, then we simply increment the scale count and re-calculate the limits for that scale value. This prevents us from oscillating between a close-to-ideal value and max all the time, instead remaining in the windows where we get good behavior. Unlike CoDel, blk-wb allows the scale count to to negative. This happens if we primarily have writes going on. Unlike positive scale counts, this doesn't change the size of the monitoring window. When the heavy writers finish, blk-bw quickly snaps back to it's stable state of a zero scale count. The patch registers a sysfs entry, 'wb_lat_usec'. This sets the latency target to me met. It defaults to 2 msec for non-rotational storage, and 75 msec for rotational storage. Setting this value to '0' disables blk-wb. Generally, a user would not have to touch this setting. We don't enable WBT on devices that are managed with CFQ, and have a non-root block cgroup attached. If we have a proportional share setup on this particular disk, then the wbt throttling will interfere with that. We don't have a strong need for wbt for that case, since we will rely on CFQ doing that for us. Signed-off-by: Jens Axboe <axboe@fb.com>
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