From 6f5986bce558e64fe867bff600a2127a3cb0c006 Mon Sep 17 00:00:00 2001 From: Joe Jin Date: Mon, 15 Aug 2011 12:51:31 +0800 Subject: xen-blkback: Don't disconnect backend until state switched to XenbusStateClosed. When do block-attach/block-detach test with below steps, umount hangs in the guest. Furthermore shutdown ends up being stuck when umounting file-systems. 1. start guest. 2. attach new block device by xm block-attach in Dom0. 3. mount new disk in guest. 4. execute xm block-detach to detach the block device in dom0 until timeout 5. Any request to the disk will hung. Root cause: This issue is caused when setting backend device's state to 'XenbusStateClosing', which sends to the frontend the XenbusStateClosing notification. When frontend receives the notification it tries to release the disk in blkfront_closing(), but at that moment the disk is still in use by guest, so frontend refuses to close. Specifically it sets the disk state to XenbusStateClosing and sends the notification to backend - when backend receives the event, it disconnects the vbd from real device, and sets the vbd device state to XenbusStateClosing. The backend disconnects the real device/file, and any IO requests to the disk in guest will end up in ether, leaving disk DEAD and set to XenbusStateClosing. When the guest wants to disconnect the disk, umount will hang on blkif_release()->xlvbd_release_gendisk() as it is unable to send any IO to the disk, which prevents clean system shutdown. Solution: Don't disconnect backend until frontend state switched to XenbusStateClosed. Signed-off-by: Joe Jin Cc: Daniel Stodden Cc: Jens Axboe Cc: Annie Li Cc: Ian Campbell [v1: Modified description a bit] Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkback/xenbus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 6cc0db1bf522..7be3d0fe8ad3 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -601,11 +601,11 @@ static void frontend_changed(struct xenbus_device *dev, break; case XenbusStateClosing: - xen_blkif_disconnect(be->blkif); xenbus_switch_state(dev, XenbusStateClosing); break; case XenbusStateClosed: + xen_blkif_disconnect(be->blkif); xenbus_switch_state(dev, XenbusStateClosed); if (xenbus_dev_is_online(dev)) break; -- cgit From 1bc05b0ae6448b20d46076899e0cc12ad999e50e Mon Sep 17 00:00:00 2001 From: Joe Jin Date: Mon, 15 Aug 2011 12:57:07 +0800 Subject: xen-blkback: fixed indentation and comments This patch fixes belows: 1. Fix code style issue. 2. Fix incorrect functions name in comments. Signed-off-by: Joe Jin Cc: Jens Axboe Cc: Ian Campbell Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkback/common.h | 2 +- drivers/block/xen-blkback/xenbus.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers') diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 9e40b283a468..00c57c90e2d6 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -46,7 +46,7 @@ #define DRV_PFX "xen-blkback:" #define DPRINTK(fmt, args...) \ - pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \ + pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \ __func__, __LINE__, ##args) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 7be3d0fe8ad3..a96cb5f893a8 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -590,7 +590,7 @@ static void frontend_changed(struct xenbus_device *dev, /* * Enforce precondition before potential leak point. - * blkif_disconnect() is idempotent. + * xen_blkif_disconnect() is idempotent. */ xen_blkif_disconnect(be->blkif); @@ -611,7 +611,7 @@ static void frontend_changed(struct xenbus_device *dev, break; /* fall through if not online */ case XenbusStateUnknown: - /* implies blkif_disconnect() via blkback_remove() */ + /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ device_unregister(&dev->dev); break; -- cgit From 65299a3b788bd274bed92f9fa3232082c9f3ea70 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 23 Aug 2011 14:50:29 +0200 Subject: block: separate priority boosting from REQ_META Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule, and lave REQ_META purely for marking requests as metadata in blktrace. All existing callers of REQ_META except for XFS are updated to also set REQ_PRIO for now. Signed-off-by: Christoph Hellwig Reviewed-by: Namhyung Kim Signed-off-by: Jens Axboe --- drivers/mmc/card/block.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers') diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 1ff5486213fb..4c1a648d00fc 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -926,6 +926,9 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq, /* * Reliable writes are used to implement Forced Unit Access and * REQ_META accesses, and are supported only on MMCs. + * + * XXX: this really needs a good explanation of why REQ_META + * is treated special. */ bool do_rel_wr = ((req->cmd_flags & REQ_FUA) || (req->cmd_flags & REQ_META)) && -- cgit From 6c4867f6469964e34c5f4ee229a2a7f71a34c7ff Mon Sep 17 00:00:00 2001 From: Carsten Emde Date: Wed, 21 Sep 2011 10:22:11 +0200 Subject: floppy: use del_timer_sync() in init cleanup When no floppy is found the module code can be released while a timer function is pending or about to be executed. CPU0 CPU1 floppy_init() timer_softirq() spin_lock_irq(&base->lock); detach_timer(); spin_unlock_irq(&base->lock); -> Interrupt del_timer(); return -ENODEV; module_cleanup(); <- EOI call_timer_fn(); OOPS Use del_timer_sync() to prevent this. Signed-off-by: Carsten Emde Signed-off-by: Thomas Gleixner Cc: Jens Axboe Cc: Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe --- drivers/block/floppy.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers') diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 98de8f418676..9955a53733b2 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4250,7 +4250,7 @@ static int __init floppy_init(void) use_virtual_dma = can_use_virtual_dma & 1; fdc_state[0].address = FDC1; if (fdc_state[0].address == -1) { - del_timer(&fd_timeout); + del_timer_sync(&fd_timeout); err = -ENODEV; goto out_unreg_region; } @@ -4261,7 +4261,7 @@ static int __init floppy_init(void) fdc = 0; /* reset fdc in case of unexpected interrupt */ err = floppy_grab_irq_and_dma(); if (err) { - del_timer(&fd_timeout); + del_timer_sync(&fd_timeout); err = -EBUSY; goto out_unreg_region; } @@ -4318,7 +4318,7 @@ static int __init floppy_init(void) user_reset_fdc(-1, FD_RESET_ALWAYS, false); } fdc = 0; - del_timer(&fd_timeout); + del_timer_sync(&fd_timeout); current_drive = 0; initialized = true; if (have_no_fdc) { @@ -4368,7 +4368,7 @@ out_unreg_blkdev: unregister_blkdev(FLOPPY_MAJOR, "fd"); out_put_disk: while (dr--) { - del_timer(&motor_off_timer[dr]); + del_timer_sync(&motor_off_timer[dr]); if (disks[dr]->queue) blk_cleanup_queue(disks[dr]->queue); put_disk(disks[dr]); -- cgit