kernel/drivers/block, branch linux-3.4.y

xen-blkback: only read request operation from shared ring once

2016-10-26T15:15:39Z

commit 1f13d75ccb806260079e0679d55d9253e370ec8a upstream. A compiler may load a switch statement value multiple times, which could be bad when the value is in memory shared with the frontend. When converting a non-native request to a native one, ensure that src->operation is only loaded once by using READ_ONCE(). This is part of XSA155. Signed-off-by: Roger Pau Monné Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk [lizf: Backported to 3.4: - adjust context - call ACCESS_ONCE instead of READ_ONCE] Signed-off-by: Zefan Li

xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing)

2016-04-27T10:55:27Z

commit a54c8f0f2d7df525ff997e2afe71866a1a013064 upstream. xen-blkfront will crash if the check to talk_to_blkback() in blkback_changed()(XenbusStateInitWait) returns an error. The driver data is freed and info is set to NULL. Later during the close process via talk_to_blkback's call to xenbus_dev_fatal() the null pointer is passed to and dereference in blkfront_closing. Signed-off-by: Cathy Avery Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Zefan Li

nbd: fix possible memory leak

2015-06-19T03:40:28Z

commit ff6b8090e26ef7649ef0cc6b42389141ef48b0cf upstream. we have already allocated memory for nbd_dev, but we were not releasing that memory and just returning the error value. Signed-off-by: Sudip Mukherjee Acked-by: Paul Clements Signed-off-by: Markus Pargmann Signed-off-by: Zefan Li

drbd: merge_bvec_fn: properly remap bvm->bi_bdev

2015-04-14T09:33:41Z

commit 3b9d35d744bb5139f9fed57f38c019bb8c7d351c upstream. This was not noticed for many years. Affects operation if md raid is used a backing device for DRBD. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe [lizf: Backported to 3.4: s/device/mdev] Signed-off-by: Zefan Li

virtio-blk: Don't free ida when disk is in use

2014-06-11T19:04:18Z

commit f4953fe6c4aeada2d5cafd78aa97587a46d2d8f9 upstream. When a file system is mounted on a virtio-blk disk, we then remove it and then reattach it, the reattached disk gets the same disk name and ids as the hot removed one. This leads to very nasty effects - mostly rendering the newly attached device completely unusable. Trying what happens when I do the same thing with a USB device, I saw that the sd node simply doesn't get free'd when a device gets forcefully removed. Imitate the same behavior for vd devices. This way broken vd devices simply are never free'd and newly attached ones keep working just fine. Signed-off-by: Alexander Graf Signed-off-by: Rusty Russell Signed-off-by: Ben Hutchings Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman

virtio-blk: Reset device after blk_cleanup_queue()

2014-06-11T19:04:17Z

commit 483001c765af6892b3fc3726576cb42f17d1d6b5 upstream. blk_cleanup_queue() will call blk_drian_queue() to drain all the requests before queue DEAD marking. If we reset the device before blk_cleanup_queue() the drain would fail. 1) if the queue is stopped in do_virtblk_request() because device is full, the q->request_fn() will not be called. blk_drain_queue() { while(true) { ... if (!list_empty(&q->queue_head)) __blk_run_queue(q) { if (queue is not stoped) q->request_fn() } ... } } Do no reset the device before blk_cleanup_queue() gives the chance to start the queue in interrupt handler blk_done(). 2) In commit b79d866c8b7014a51f611a64c40546109beaf24a, We abort requests dispatched to driver before blk_cleanup_queue(). There is a race if requests are dispatched to driver after the abort and before the queue DEAD mark. To fix this, instead of aborting the requests explicitly, we can just reset the device after after blk_cleanup_queue so that the device can complete all the requests before queue DEAD marking in the drain process. Cc: Rusty Russell Cc: virtualization@lists.linux-foundation.org Cc: kvm@vger.kernel.org Signed-off-by: Asias He Acked-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Signed-off-by: Ben Hutchings Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman

virtio-blk: Call del_gendisk() before disable guest kick

2014-06-11T19:04:17Z

commit 02e2b124943648fba0a2ccee5c3656a5653e0151 upstream. del_gendisk() might not return due to failing to remove the /sys/block/vda/serial sysfs entry when another thread (udev) is trying to read it. virtblk_remove() vdev->config->reset() : guest will not kick us through interrupt del_gendisk() device_del() kobject_del(): got stuck, sysfs entry ref count non zero sysfs_open_file(): user space process read /sys/block/vda/serial sysfs_get_active() : got sysfs entry ref count dev_attr_show() virtblk_serial_show() blk_execute_rq() : got stuck, interrupt is disabled request cannot be finished This patch fixes it by calling del_gendisk() before we disable guest's interrupt so that the request sent in virtblk_serial_show() will be finished and del_gendisk() will success. This fixes another race in hot-unplug process. It is save to call del_gendisk(vblk->disk) before flush_work(&vblk->config_work) which might access vblk->disk, because vblk->disk is not freed until put_disk(vblk->disk). Cc: virtualization@lists.linux-foundation.org Cc: kvm@vger.kernel.org Signed-off-by: Asias He Acked-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Signed-off-by: Ben Hutchings Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman

virtio-blk: Fix hot-unplug race in remove method

2014-06-11T19:04:17Z

commit b79d866c8b7014a51f611a64c40546109beaf24a upstream. If we reset the virtio-blk device before the requests already dispatched to the virtio-blk driver from the block layer are finised, we will stuck in blk_cleanup_queue() and the remove will fail. blk_cleanup_queue() calls blk_drain_queue() to drain all requests queued before DEAD marking. However it will never success if the device is already stopped. We'll have q->in_flight[] > 0, so the drain will not finish. How to reproduce the race: 1. hot-plug a virtio-blk device 2. keep reading/writing the device in guest 3. hot-unplug while the device is busy serving I/O Test: ~1000 rounds of hot-plug/hot-unplug test passed with this patch. Changes in v3: - Drop blk_abort_queue and blk_abort_request - Use __blk_end_request_all to complete request dispatched to driver Changes in v2: - Drop req_in_flight - Use virtqueue_detach_unused_buf to get request dispatched to driver Signed-off-by: Asias He Signed-off-by: Rusty Russell Signed-off-by: Ben Hutchings Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman

virtio_blk: Drop unused request tracking list

2014-06-11T19:04:17Z

commit f65ca1dc6a8c81c6bd72297d4399ec5f4c1f3a01 upstream. Benchmark shows small performance improvement on fusion io device. Before: seq-read : io=1,024MB, bw=19,982KB/s, iops=39,964, runt= 52475msec seq-write: io=1,024MB, bw=20,321KB/s, iops=40,641, runt= 51601msec rnd-read : io=1,024MB, bw=15,404KB/s, iops=30,808, runt= 68070msec rnd-write: io=1,024MB, bw=14,776KB/s, iops=29,552, runt= 70963msec After: seq-read : io=1,024MB, bw=20,343KB/s, iops=40,685, runt= 51546msec seq-write: io=1,024MB, bw=20,803KB/s, iops=41,606, runt= 50404msec rnd-read : io=1,024MB, bw=16,221KB/s, iops=32,442, runt= 64642msec rnd-write: io=1,024MB, bw=15,199KB/s, iops=30,397, runt= 68991msec Signed-off-by: Asias He Signed-off-by: Rusty Russell [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman

nbd: fsync and kill block device on shutdown

2014-06-07T23:02:10Z

commit 3a2d63f87989e01437ba994df5f297528c353d7d upstream. There are two problems with shutdown in the NBD driver. 1: Receiving the NBD_DISCONNECT ioctl does not sync the filesystem. This patch adds the sync operation into __nbd_ioctl()'s NBD_DISCONNECT handler. This is useful because BLKFLSBUF is restricted to processes that have CAP_SYS_ADMIN, and the NBD client may not possess it (fsync of the block device does not sync the filesystem, either). 2: Once we clear the socket we have no guarantee that later reads will come from the same backing storage. The patch adds calls to kill_bdev() in __nbd_ioctl()'s socket clearing code so the page cache is cleaned, lest reads that hit on the page cache will return stale data from the previously-accessible disk. Example: # qemu-nbd -r -c/dev/nbd0 /dev/sr0 # file -s /dev/nbd0 /dev/stdin: # UDF filesystem data (version 1.5) etc. # qemu-nbd -d /dev/nbd0 # qemu-nbd -r -c/dev/nbd0 /dev/sda # file -s /dev/nbd0 /dev/stdin: # UDF filesystem data (version 1.5) etc. While /dev/sda has: # file -s /dev/sda /dev/sda: x86 boot sector; etc. Signed-off-by: Paolo Bonzini Acked-by: Paul Clements Cc: Alex Bligh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: - Adjusted context - s/\bnbd\b/lo/ - Incorporate export of kill_bdev() from commit ff01bb483265 ('fs: move code out of buffer.c')] Signed-off-by: Ben Hutchings [hq: Backported to 3.4: Adjusted context] Signed-off-by: Qiang Huang Signed-off-by: Greg Kroah-Hartman