linux/drivers
Paolo Bonzini 3a2d63f879 nbd: fsync and kill block device on shutdown
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 <pbonzini@redhat.com>
Acked-by: Paul Clements <Paul.Clements@steeleye.com>
Cc: Alex Bligh <alex@alex.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:22 -08:00
..
accessibility
acpi ACPI and power management fixes for 3.9-rc1 2013-02-25 21:25:17 -08:00
amba
ata 1) apply, and then revert, the sysfs export of ATA host controller number. 2013-02-24 17:32:15 -08:00
atm atm/nicstar: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
auxdisplay
base Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
bcma
block nbd: fsync and kill block device on shutdown 2013-02-27 19:10:22 -08:00
bluetooth Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-02-21 17:40:58 -08:00
bus
cdrom
char drivers/char/misc.c:misc_register(): do not loop on misc_list unconditionally 2013-02-27 19:10:21 -08:00
clk arm-soc: device tree conversions 2013-02-21 15:38:49 -08:00
clocksource Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-26 19:43:20 -08:00
connector
cpufreq ACPI and power management fixes for 3.9-rc1 2013-02-25 21:25:17 -08:00
cpuidle arm-soc: soc-specific updates 2013-02-21 15:27:22 -08:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2013-02-25 15:56:15 -08:00
dca dca: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
devfreq
dio
dma dmaengine: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
edac Driver core patches for 3.9-rc1 2013-02-21 12:05:51 -08:00
eisa
extcon Char/Misc driver patches for 3.9-rc1 2013-02-21 13:57:13 -08:00
firewire firewire: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
firmware memory-hotplug: remove /sys/firmware/memmap/X sysfs 2013-02-23 17:50:12 -08:00
gpio gpio: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
gpu drm/vmwgfx: convert to idr_alloc() 2013-02-27 19:10:16 -08:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
hsi
hv Char/Misc driver patches for 3.9-rc1 2013-02-21 13:57:13 -08:00
hwmon ACPI and power management updates for 3.9-rc1 2013-02-20 11:26:56 -08:00
hwspinlock
i2c idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.c 2013-02-27 19:10:20 -08:00
ide Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
idle Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-22 19:25:09 -08:00
iio Staging tree update for 3.9-rc1 2013-02-21 12:11:44 -08:00
infiniband idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.c 2013-02-27 19:10:20 -08:00
input This is the MFD pull request for the 3.9 merge window. 2013-02-24 20:00:58 -08:00
iommu Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
ipack Char/Misc driver patches for 3.9-rc1 2013-02-21 13:57:13 -08:00
irqchip arm-soc: cleanups 2013-02-21 14:58:40 -08:00
isdn Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
leds Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds 2013-02-26 09:29:02 -08:00
lguest All trivial, thanks to the stuff which didn't quite make it time. 2013-02-26 14:49:12 -08:00
macintosh Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-02-23 17:09:55 -08:00
mailbox
md dm: convert to idr_alloc() 2013-02-27 19:10:17 -08:00
media Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
memory
memstick memstick: convert to idr_alloc() 2013-02-27 19:10:17 -08:00
message
mfd mfd: convert to idr_alloc() 2013-02-27 19:10:17 -08:00
misc misc/tifm_core: convert to idr_alloc() 2013-02-27 19:10:17 -08:00
mmc mmc: convert to idr_alloc() 2013-02-27 19:10:17 -08:00
mtd mtd: convert to idr_alloc() 2013-02-27 19:10:18 -08:00
net ppp: convert to idr_alloc() 2013-02-27 19:10:18 -08:00
nfc
ntb
nubus
of Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-02-21 17:40:58 -08:00
oprofile oprofilefs: add missing ->i_mutex locking in object creation 2013-02-22 23:31:38 -05:00
parisc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
parport Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2013-02-21 17:54:03 -08:00
pci Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
pcmcia Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-02-21 17:40:58 -08:00
pinctrl arm-soc: device tree conversions 2013-02-21 15:38:49 -08:00
platform Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
pnp Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
power power: convert to idr_alloc() 2013-02-27 19:10:18 -08:00
pps pps: convert to idr_alloc() 2013-02-27 19:10:18 -08:00
ps3
ptp
pwm pwm: Changes for v3.9-rc1 2013-02-26 09:34:29 -08:00
rapidio
regulator
remoteproc remoteproc: convert to idr_alloc() 2013-02-27 19:10:18 -08:00
rpmsg rpmsg: convert to idr_alloc() 2013-02-27 19:10:18 -08:00
rtc This is the MFD pull request for the 3.9 merge window. 2013-02-24 20:00:58 -08:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
sbus Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
scsi scsi/lpfc: convert to idr_alloc() 2013-02-27 19:10:19 -08:00
sfi
sh
sn
spi arm-soc: soc-specific updates 2013-02-21 15:27:22 -08:00
ssb
staging Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
target target/iscsi: convert to idr_alloc() 2013-02-27 19:10:18 -08:00
tc
thermal thermal: convert to idr_alloc() 2013-02-27 19:10:19 -08:00
tty sysrq: don't depend on weak undefined arrays to have an address that compares as NULL 2013-02-27 09:59:50 -08:00
uio uio: convert to idr_alloc() 2013-02-27 19:10:19 -08:00
usb Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
uwb
vfio vfio: convert to idr_alloc() 2013-02-27 19:10:19 -08:00
vhost Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-02-26 11:42:23 -08:00
video backlight: add new lp8788 backlight driver 2013-02-27 19:10:09 -08:00
virt
virtio All trivial, thanks to the stuff which didn't quite make it time. 2013-02-26 14:49:12 -08:00
vlynq
vme
w1 Char/Misc driver patches for 3.9-rc1 2013-02-21 13:57:13 -08:00
watchdog Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
xen Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
zorro new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
Kconfig Char/Misc driver patches for 3.9-rc1 2013-02-21 13:57:13 -08:00
Makefile Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-02-23 17:09:55 -08:00