Just add s390 to the list of architectures that don't want this driver.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
We are using sizeof operator for an array given as function argument,
which is incorrect.
Signed-off-by: Syam Sidhardhan <s.syam@samsung.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
access_ok() always returns 'true' on s390. Therefore all calls
are quite pointless and can be removed.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
If the maximum length specified for the to be accessed string for
strncpy_from_user() and strnlen_user() is zero the following incorrect
values would be returned or incorrect memory accesses would happen:
strnlen_user_std() and strnlen_user_pt() incorrectly return "1"
strncpy_from_user_pt() would incorrectly access "dst[maxlen - 1]"
strncpy_from_user_mvcos() would incorrectly return "-EFAULT"
Fix all these oddities by adding early checks.
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Always stay within page boundaries when copying from user within
strlen_user_mvcos()/strncpy_from_user_mvcos(). This allows to
shorten the code a bit and may prevent unnecessary faults, since
we copy quite large amounts of memory to kernel space.
Also directly call the mvcos variants of copy_from_user() to
avoid indirect branches.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Failfast bit was set incorrectly.
Use set_bit to enable failfast.
Reviewed-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add hint to the page tables that we don't care about the change bit
in storage keys that belong to vmemmap pages.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
... otherwise the path we'd built isn't worth much. Don't accept such fids
obtained from paths unless dentry is still alived by the end of the work.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The physical memory fixmapped for the pvclock clock_gettime vsyscall
was allocated, and thus is not a kernel symbol. __pa() is the proper
method to use in this case.
Fixes the crash below when booting a next-20130204+ smp guest on a
3.8-rc5+ KVM host.
[ 0.666410] udevd[97]: starting version 175
[ 0.674043] udevd[97]: udevd:[97]: segfault at ffffffffff5fd020
ip 00007fff069e277f sp 00007fff068c9ef8 error d
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Merge third patch-bumb from Andrew Morton:
"This wraps me up for -rc1.
- Lots of misc stuff and things which were deferred/missed from
patchbombings 1 & 2.
- ocfs2 things
- lib/scatterlist
- hfsplus
- fatfs
- documentation
- signals
- procfs
- lockdep
- coredump
- seqfile core
- kexec
- Tejun's large IDR tree reworkings
- ipmi
- partitions
- nbd
- random() things
- kfifo
- tools/testing/selftests updates
- Sasha's large and pointless hlist cleanup"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (163 commits)
hlist: drop the node parameter from iterators
kcmp: make it depend on CHECKPOINT_RESTORE
selftests: add a simple doc
tools/testing/selftests/Makefile: rearrange targets
selftests/efivarfs: add create-read test
selftests/efivarfs: add empty file creation test
selftests: add tests for efivarfs
kfifo: fix kfifo_alloc() and kfifo_init()
kfifo: move kfifo.c from kernel/ to lib/
arch Kconfig: centralise CONFIG_ARCH_NO_VIRT_TO_BUS
w1: add support for DS2413 Dual Channel Addressable Switch
memstick: move the dereference below the NULL test
drivers/pps/clients/pps-gpio.c: use devm_kzalloc
Documentation/DMA-API-HOWTO.txt: fix typo
include/linux/eventfd.h: fix incorrect filename is a comment
mtd: mtd_stresstest: use prandom_bytes()
mtd: mtd_subpagetest: convert to use prandom library
mtd: mtd_speedtest: use prandom_bytes
mtd: mtd_pagetest: convert to use prandom library
mtd: mtd_oobtest: convert to use prandom library
...
The original device tree binding for this driver, from Viresh Kumar
unfortunately conflicted with the generic DMA binding, and did not allow
to completely seperate slave device configuration from the controller.
This is an attempt to replace it with an implementation of the generic
binding, but it is currently completely untested, because I do not have
any hardware with this particular controller.
The patch applies on top of the slave-dma tree, which contains both the base
support for the generic DMA binding, as well as the earlier attempt from
Viresh. Both of these are currently not merged upstream however.
This version incorporates feedback from Viresh Kumar, Andy Shevchenko
and Russell King.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Vinod Koul <vinod.koul@linux.intel.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
It is actually a vector not a sg, so nr_vecs is better than sg_num.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The page++ is wrong. It makes bio_add_pc_page() pointing to a wrong page
address if the 'while (len > 0 && data_len > 0) { ... }' loop is
executed more than one once.
Signed-off-by: Asias He <asias@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Inclues sbp_exit, fileio_module_exit, iblock_module_exit and
pscsi_module_exit.
Note: rd_module_exit() can not be annotated by __exit, becasue it is
called by target_core_init_configfs() which is annotated by __init.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since kcmp syscall has been implemented (initially on x86 architecture) a
number of other archs wire it up as well: xtensa, sparc, sh, s390, mips,
microblaze, m68k (not taking into account those who uses
<asm-generic/unistd.h> for syscall numbers definitions).
But the Makefile, which turns kcmp.o generation on still depends on former
config-x86. Thus get rid of this limitation and make kcmp.o depend on
CHECKPOINT_RESTORE option.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change adds a little documentation to the tests under
tools/testing/selftests/, based on akpm's explanation.
[akpm@linux-foundation.org: move from Documentation to tools/testing/selftests/README.txt]
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Do it one-per-line to reduce patch conflict pain.
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Test that reads from a newly-created efivarfs file (with no data written)
will return EOF.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Lingzhu Xiang <lxiang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Lingzhu Xiang <lxiang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change adds a few initial efivarfs tests to the
tools/testing/selftests directory.
The open-unlink test is based on code from Lingzhu Xiang.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Lingzhu Xiang <lxiang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix kfifo_alloc() and kfifo_init() to alloc at least the requested number
of elements. Since the kfifo operates on power of 2 the request size will
be rounded up to the next power of two.
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change it to CONFIG_HAVE_VIRT_TO_BUS and set it in all architecures
that already provide virt_to_bus().
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: H Hartley Sweeten <hartleys@visionengravers.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Also fixes some whitespace inconsistency in Kconfig and w1_family.h when
DS2408 chip support was added.
Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The dereference should be moved below the NULL test.
spatch with a semantic match is used to found this.
(http://coccinelle.lip6.fr/)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
devm_kzalloc allocates memory that is released when a driver detaches.
This patch uses devm_kzalloc for data that is allocated in the probe
function of a platform device and is only freed in the remove function.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Comment in eventfd.h referred to 'include/asm-generic/fcntl.h'
while the correct path is 'include/uapi/asm-generic/fcntl.h'.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes home-brewed pseudo-random number generator and use
prandom library.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Laight <david.laight@aculab.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use prandom_bytes instead of equivalent local function.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Laight <david.laight@aculab.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes home-brewed pseudo-random number generator and use
prandom library.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Laight <david.laight@aculab.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes home-brewed pseudo-random number generator and use
prandom library.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Laight <david.laight@aculab.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using prandom_bytes() is enough. Because this data is only used
for testing, not used for cryptographic use.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Laight <david.laight@aculab.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the wrong comment about the return value of clone_uts_ns()
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I just fixed this in "drivers/block/rbd.c" and I noticed that
"drivers/block/nbd.c" has the same problem. Fix a warning issued by
sparse by adding some lockdep annotations to indicate the queue lock gets
dropped (because it's held when do_nbd_request() is called) and
re-acquired within the function.
Signed-off-by: Alex Elder <elder@inktank.com>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Paul Clements <paul.clements@us.sios.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation/blockdev/nbd.txt contained some documentation which was
horribly outdated and probably still dates from the original patch that
added NBD support to the kernel.
This patch removes the useless and outdated bits. The tools on nbd.sf.net
are fully documented in manpages, which is where documentation for the
non-kernel bits should live.
Additionally, add a reference to the MAINTAINERS file for the nbd-general
mailinglist that is used for discussion of the userland tools and the
kernel module already.
Signed-off-by: Wouter Verhelst <w@uter.be>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pass the read-only flag to set_device_ro, so that it will be visible to
the block layer and in sysfs.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Cc: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Currently, the NBD device does not accept flush requests from the Linux
block layer. If the NBD server opened the target with neither O_SYNC nor
O_DSYNC, however, the device will be effectively backed by a writeback
cache. Without issuing flushes properly, operation of the NBD device will
not be safe against power losses.
The NBD protocol has support for both a cache flush command and a FUA
command flag; the server will also pass a flag to note its support for
these features. This patch adds support for the cache flush command and
flag. In the kernel, we receive the flags via the NBD_SET_FLAGS ioctl,
and map NBD_FLAG_SEND_FLUSH to the argument of blk_queue_flush. When the
flag is active the block layer will send REQ_FLUSH requests, which we
translate to NBD_CMD_FLUSH commands.
FUA support is not included in this patch because all free software
servers implement it with a full fdatasync; thus it has no advantage over
supporting flush only. Because I [Paolo] cannot really benchmark it in a
realistic scenario, I cannot tell if it is a good idea or not. It is also
not clear if it is valid for an NBD server to support FUA but not flush.
The Linux block layer gives a warning for this combination, the NBD
protocol documentation says nothing about it.
The patch also fixes a small problem in the handling of flags: nbd->flags
must be cleared at the end of NBD_DO_IT, but the driver was not doing
that. The bug manifests itself as follows. Suppose you two different
client/server pairs to start the NBD device. Suppose also that the first
client supports NBD_SET_FLAGS, and the first server sends
NBD_FLAG_SEND_FLUSH; the second pair instead does neither of these two
things. Before this patch, the second invocation of NBD_DO_IT will use a
stale value of nbd->flags, and the second server will issue an error every
time it receives an NBD_CMD_FLUSH command.
This bug is pre-existing, but it becomes much more important after this
patch; flush failures make the device pretty much unusable, unlike
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Bligh <alex@alex.org.uk>
Acked-by: Paul Clements <Paul.Clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Heiko Carstens
Syam Sidhardhan
Stefan Haberland
Al Viro
Peter Hurley
Linus Torvalds
Arnd Bergmann
Asias He
Sasha Levin
Cyrill Gorcunov
Jeremy Kerr
Andrew Morton
Stefani Seibold
Stephen Rothwell
Mariusz Bialonczyk
Wei Yongjun
Julia Lawall
Martin Sustrik
Akinobu Mita
Yuanhan Liu
Alex Elder
Wouter Verhelst
Paolo Bonzini
Alex Bligh