md/raid submits a lot of IO from the various raid threads.
So adding start/finish plug calls to those so that some
plugging happens.
Signed-off-by: NeilBrown <neilb@suse.de>
If we know we are going to punt to kblockd, we can drop the queue
lock before calling into __blk_run_queue() since it only does a
safe bit test and a workqueue call. Since kblockd needs to grab
this very lock as one of the first things it does, it's a good
optimization to drop the lock before waking kblockd.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
MD can't use this since it really requires us to be able to
keep more than a single piece of state for the unplug. Commit
048c9374 added the required support for MD, so get rid of this
now unused code.
This reverts commit f75664570d.
Conflicts:
block/blk-core.c
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
md/raid requires an unplug callback, but as it does not uses
requests the current code cannot provide one.
So allow arbitrary callbacks to be attached to the blk_plug.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Several tests in the ipv6 routing code check IFF_LOOPBACK, and
allowing stacking such as VLAN'ing on top of loopback results in a
netdevice which reports IFF_LOOPBACK but really isn't the loopback
device.
Instead of spamming the ipv6 routing code with even more special tests,
simply disallow VLAN over loopback.
The result of this patch is:
# modprobe 8021q
# vconfig add lo 43
ERROR: trying to add VLAN #43 to IF -:lo:- error: Operation not supported
Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Because of speculative event roll back, it is possible for some event coutners
to decrease between reads on POWER7. This causes a problem with the way that
counters are updated. Delta calues are calculated in a 64 bit value and the
top 32 bits are masked. If the register value has decreased, this leaves us
with a very large positive value added to the kernel counters. This patch
protects against this by skipping the update if the delta would be negative.
This can lead to a lack of precision in the coutner values, but from my testing
the value is typcially fewer than 10 samples at a time.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Cc: stable@kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This problem was noticed on an MPC855T platform. Ftrace did oops
when trying to write to the kernel text segment.
Many thanks to Joakim for finding the root cause of this problem.
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We currently enable interrupts before the dispatch log for the boot
cpu is setup. If a timer interrupt comes in early enough we oops in
scan_dispatch_log:
Unable to handle kernel paging request for data at address 0x00000010
...
.scan_dispatch_log+0xb0/0x170
.account_system_vtime+0xa0/0x220
.irq_enter+0x88/0xc0
.do_IRQ+0x48/0x230
The patch below adds a check to scan_dispatch_log to ensure the
dispatch log has been allocated.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
PAPR specifies that DTL buffers can not cross AMS environments (aka CMO
in the PAPR) and can not cross a memory entitlement granule boundary
(4k). This is found in section 14.11.3.2 H_REGISTER_VPA of the PAPR.
kmalloc does not guarantee an alignment of the allocation, though,
beyond 8 bytes (at least in my understanding). Create a special kmem
cache for DTL buffers with the alignment requirement.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Recent commit b987812b3f caused
a compile failure on UP because a considerably large block
of the file was included within CONFIG_SMP, hence making a stub
function not exposed on UP builds when it needed to be.
Relocate the stub to the #else /* ! CONFIG_SMP */ section
and also annotate the relevant else/endif so that nobody
else falls into the same trap I did.
Reported-by: Michael Guntsche <mike@it-loops.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch fixes port identification on optic devices when there's no link on the port.
Signed-off-by: Yaniv Rosner <yanivr@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
ARM: SAMSUNG: Fix warning 's3c_pm_show_resume_irqs' defined but not used
ARM: SAMSUNG: Fix build failure in PM CRC check code
ARM: S5P: Remove unused s3c_pm_check_resume_pin
Following commit 091738a266 ("genirq: Remove real old transition
functions") we removed an automatic conversion of no_irq_chip to
dummy_irq_chip. This change needs to be propagated back into the alpha
backend.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a new warning in gcc 4.6. Several of these variables are
used within #if 0 code, which probably ought to be removed. Most
of the changes are legitimate cleanups.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are outstanding gcc 4.6 warnings that need to be cleaned up
in the subdirectory. No sense forcing the issue immediately.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While checking unregister_filesystem for saftey vs extra calls for
"ext4: register ext2 and ext3 alias after ext4" I realized that
the synchronize_rcu() was called on the error path but not on
the success path.
Cc: stable (2.6.38)
Signed-off-by: Milton Miller <miltonm@bga.com>
[ This probably won't really make a difference since commit d863b50ab0
("vfs: call rcu_barrier after ->kill_sb()"), but it's the right thing
to do. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Apparently some distros set i2c-algo-bit.bit_test to 1 by
default. In some cases this causes i2c_bit_add_bus
to fail and prevents the i2c bus from being added. In the
radeon case, we fail to add the ddc i2c buses which prevents
the driver from being able to detect attached monitors.
The i2c bus works fine even if bit_test fails. This is likely
due to gpio switching that is required and handled in the
pre/post_xfer hooks, so call the pre/post_xfer hooks in the
bit test as well.
Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=36221
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org [.38 down to .34]
When warning on the use of deprecated i2c_driver methods
attach_adapter and detach_adapter, mention the name of the driver
which needs to be updated.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Issue manifests as:
In file included from arch/arm/mach-pxa/include/mach/hardware.h:62,
from arch/arm/mach-pxa/include/mach/gpio.h:28,
from /home/jic23/src/kernel/temp-remove/arch/arm/include/asm/gpio.h:5,
from include/linux/gpio.h:7,
from drivers/staging/iio/gyro/adis16080_core.c:8:
/home/jic23/src/kernel/temp-remove/arch/arm/include/asm/cputype.h:57: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'read_cpuid_id'
...
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: make unplug timer trace event correspond to the schedule() unplug
block: let io_schedule() flush the plug inline
* 'usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (43 commits)
Revert "USB: isp1760-hcd: move imask clear after pending work is done"
xHCI: Implement AMD PLL quirk
xhci: Tell USB core both roothubs lost power.
usbcore: Bug fix: system can't suspend with USB3.0 device connected to USB3.0 hub
USB: Fix unplug of device with active streams
USB: xhci - also free streams when resetting devices
xhci: Fix NULL pointer deref in handle_port_status()
USB: xhci - fix math in xhci_get_endpoint_interval()
USB: xhci: simplify logic of skipping missed isoc TDs
USB: xhci - remove excessive 'inline' markings
USB: xhci: unsigned char never equals -1
USB: xhci - fix unsafe macro definitions
USB: fix formatting of SuperSpeed endpoints in /proc/bus/usb/devices
USB: isp1760-hcd: move imask clear after pending work is done
USB: fsl_qe_udc: send ZLP when zero flag and length % maxpacket == 0
usb: qcserial add missing errorpath kfrees
usb: qcserial avoid pointing to freed memory
usb: Fix qcserial memory leak on rmmod
USB: ftdi_sio: add ids for Hameg HO720 and HO730
USB: option: Added support for Samsung GT-B3730/GT-B3710 LTE USB modem.
...
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf_event: Fix cgrp event scheduling bug in perf_enable_on_exec()
perf: Fix a build error with some GCC versions
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Fix erroneous all_pinned logic
sched: Fix sched-domain avg_load calculation
* 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
RTC: rtc-mrst: follow on to the change of rtc_device_register()
RTC: add missing "return 0" in new alarm func for rtc-bfin.c
RTC: Fix s3c compile error due to missing s3c_rtc_setpie
RTC: Fix early irqs caused by calling rtc_set_alarm too early
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, amd: Disable GartTlbWlkErr when BIOS forgets it
x86, NUMA: Fix fakenuma boot failure
x86/mrst: Fix boot crash caused by incorrect pin to irq mapping
x86/ce4100: Add reg property to bridges
It's a pretty close match to what we had before - the timer triggering
would mean that nobody unplugged the plug in due time, in the new
scheme this matches very closely what the schedule() unplug now is.
It's essentially the difference between an explicit unplug (IO unplug)
or an implicit unplug (timer unplug, we scheduled with pending IO
queued).
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Linus correctly observes that the most important dispatch cases
are now done from kblockd, this isn't ideal for latency reasons.
The original reason for switching dispatches out-of-line was to
avoid too deep a stack, so by _only_ letting the "accidental"
flush directly in schedule() be guarded by offload to kblockd,
we should be able to get the best of both worlds.
So add a blk_schedule_flush_plug() that offloads to kblockd,
and only use that from the schedule() path.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Everytime we try to allocate disk space we try and see if we can pre-emptively
allocate a chunk, but in the common case we don't allocate anything, so there is
no sense in taking the chunk_mutex at all. So instead if we are allocating a
chunk, mark it in the space_info so we don't get two people trying to allocate
at the same time. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Reviewed-by: Liu Bo <liubo2009@cn.fujitsu.com>
A recent commit caches the extent state in end_bio_extent_readpage,
but the search it does should look for locked extents. This
fixes things to make it more effective.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
net/9p: nwname should be an unsigned int
9p: Fix sparse error
fs/9p: Fix error reported by coccicheck
9p: revert tsyncfs related changes
fs/9p: Use write_inode for data sync on server
fs/9p: Fix revalidate to return correct value
* 'fixes' of master.kernel.org:/home/rmk/linux-2.6-arm:
ARM: 6879/1: fix personality test wrt usage of domain handlers
ARM: 6878/1: fix personality flag propagation across an exec
ARM: 6877/1: the ADDR_NO_RANDOMIZE personality flag should be honored with mmap()
ARM: 6876/1: Kconfig.debug: Remove unused CONFIG_DEBUG_ERRORS
ARM: pxa: convert incorrect IRQ_TO_IRQ() to irq_to_gpio()
ARM: mmp: align NR_BUILTIN_GPIO with gpio interrupt number
ARM: pxa: align NR_BUILTIN_GPIO with GPIO interrupt number
ARM: pxa: always clear LPM bits for PXA168 MFPR
pcmcia: limit pxa2xx_trizeps4 subdriver to trizeps4 platform
pcmcia: limit pxa2xx_balloon3 subdriver to balloon3 platform
ARM: pxafb: Fix access to nonexistent member of pxafb_info
ARM: 6872/1: arch:common:Makefile Remove unused config in the Makefile.
ARM: 6868/1: Preserve the VFP state during fork
ARM: 6867/1: Introduce THREAD_NOTIFY_COPY for copy_thread() hooks
ARM: 6866/1: Do not restrict HIGHPTE to !OUTER_CACHE
ARM: 6865/1: perf: ensure pass through zero is counted on overflow
ARM: 6864/1: hw_breakpoint: clear DBGVCR out of reset
ARM: Only allow PM_SLEEP with CPUs which support suspend
ARM: Make consolidated PM sleep code depend on PM_SLEEP
This patch disables GartTlbWlk errors on AMD Fam10h CPUs if
the BIOS forgets to do is (or is just too old). Letting
these errors enabled can cause a sync-flood on the CPU
causing a reboot.
The AMD BKDG recommends disabling GART TLB Wlk Error completely.
This patch is the fix for
https://bugzilla.kernel.org/show_bug.cgi?id=33012
on my machine.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/20110415131152.GJ18463@8bytes.org
Tested-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
During RCU walk in path_lookupat and path_openat, the rcu lookup
frequently failed if looking up an absolute path, because when root
directory was looked up, seq number was not properly set in nameidata.
We dropped out of RCU walk in nameidata_drop_rcu due to mismatch in
directory entry's seq number. We reverted to slow path walk that need
to take references.
With the following patch, I saw a 50% increase in an exim mail server
benchmark throughput on a 4-socket Nehalem-EX system.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: stable@kernel.org (v2.6.38)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric VAn Hensbergen <ericvh@gmail.com>
Now that we use write_inode to flush server
cache related to fid, we don't need tsyncfs either fort dotl or dotu
protocols. For dotu this helps to do a more efficient server flush.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
revalidate should return > 0 on success. Also return 0 on ENOENT
to force do_revalidate to return NULL dentry;
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
find_free_extent likes to allocate in contiguous clusters,
which makes writeback faster, especially on SSD storage. As
the FS fragments, these clusters become harder to find and we have
to decide between allocating a new chunk to make more clusters
or giving up on the cluster to allocate from the free space
we have.
Right now it creates too many chunks, and you can end up with
a whole FS that is mostly empty metadata chunks. This commit
changes the allocation code to be more strict and only
allocate new chunks when we've made good use of the chunks we
already have.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Currently, numa=fake boot parameter is broken. If it's used,
kernel may panic due to devide by zero error depending on CPU
configuration
Call Trace:
[<ffffffff8104ad4c>] find_busiest_group+0x38c/0xd30
[<ffffffff81086aff>] ? local_clock+0x6f/0x80
[<ffffffff81050533>] load_balance+0xa3/0x600
[<ffffffff81050f53>] idle_balance+0xf3/0x180
[<ffffffff81550092>] schedule+0x722/0x7d0
[<ffffffff81550538>] ? wait_for_common+0x128/0x190
[<ffffffff81550a65>] schedule_timeout+0x265/0x320
[<ffffffff81095815>] ? lock_release_holdtime+0x35/0x1a0
[<ffffffff81550538>] ? wait_for_common+0x128/0x190
[<ffffffff8109bb6c>] ? __lock_release+0x9c/0x1d0
[<ffffffff815534e0>] ? _raw_spin_unlock_irq+0x30/0x40
[<ffffffff815534e0>] ? _raw_spin_unlock_irq+0x30/0x40
[<ffffffff81550540>] wait_for_common+0x130/0x190
[<ffffffff81051920>] ? try_to_wake_up+0x510/0x510
[<ffffffff8155067d>] wait_for_completion+0x1d/0x20
[<ffffffff8107f36c>] kthread_create_on_node+0xac/0x150
[<ffffffff81077bb0>] ? process_scheduled_works+0x40/0x40
[<ffffffff8155045f>] ? wait_for_common+0x4f/0x190
[<ffffffff8107a283>] __alloc_workqueue_key+0x1a3/0x590
[<ffffffff81e0cce2>] cpuset_init_smp+0x6b/0x7b
[<ffffffff81df3d07>] kernel_init+0xc3/0x182
[<ffffffff8155d5e4>] kernel_thread_helper+0x4/0x10
[<ffffffff81553cd4>] ? retint_restore_args+0x13/0x13
[<ffffffff81df3c44>] ? start_kernel+0x400/0x400
[<ffffffff8155d5e0>] ? gs_change+0x13/0x13
The divede by zero is caused by the following line,
group->cpu_power==0:
kernel/sched_fair.c::update_sg_lb_stats()
/* Adjust by relative CPU power of the group */
sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power;
This regression was caused by commit e23bba6044 ("x86-64, NUMA: Unify
emulated distance mapping") because it changes cpu -> node
mapping in the process of dropping fake_physnodes().
old) all cpus are assinged node 0
now) cpus are assigned round robin
(the logic is implemented by numa_init_array())
Note: The change in behavior only happens if the system doesn't
have neither ACPI SRAT table nor AMD northbridge NUMA
information.
Round robin assignment doesn't work because init_numa_sched_groups_power()
assumes all logical cpus in the same physical cpu share the same node
(then it only accounts for group_first_cpu()), and the simple round robin
breaks the above assumption.
Thus, this patch implements a reassignment of node-ids if buggy firmware
or numa emulation makes wrong cpu node map. Tt enforce all logical cpus
in the same physical cpu share the same node.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/20110415203928.1303.A69D9226@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
perf stat doesn't mmap and its perfectly fine for it to use task-bound
counters with inheritance.
So set the attr.inherit on the caller and leave the syscall itself to
validate it.
When the mmap fails perf_evlist__mmap will just emit a warning if this
is the failure reason.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Link: http://lkml.kernel.org/r/20110414170121.GC3229@ghostprotocols.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In hists browser, press hotkey 'a' to annotate current symbol.
Now it causes segment fault if 'a' is pressed on a null symbol.
Here are 2 small bugs:
- In perf_evsel__hists_browse, the condition check after 'a' is pressed
is not correct, we should check ->sym instead of ->map.
- In symbol__tui_annotate we must check whether sym is NULL or not
before getting annotation structure.
This patch fixes above 2 small bugs.
Link: http://lkml.kernel.org/r/1302244286.4106.36.camel@minggr.sh.intel.com
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: only force kblockd unplugging from the schedule() path
block: cleanup the block plug helper functions
block, blk-sysfs: Use the variable directly instead of a function call
block: move queue run on unplug to kblockd
block: kill queue_sync_plugs()
block: readd plug trace event
block: add callback function for unplug notification
block: add comment on why we save and disable interrupts in flush_plug_list()
block: fixup block IO unplug trace call
block: remove block_unplug_timer() trace point
block: splice plug list to local context
* 'linux-next' of git://git.infradead.org/ubifs-2.6:
UBIFS: fix compilation warnings when compiling with gcc 4.5
UBIFS: fix oops when R/O file-system is fsync'ed
The FLAGS_HAS_TIMEOUT flag was not getting set, causing the restart_block to
restart futex_wait() without a timeout after a signal.
Commit b41277dc7a in 2.6.38 introduced the regression by accidentally
removing the the FLAGS_HAS_TIMEOUT assignment from futex_wait() during the setup
of the restart block. Restore the originaly behavior.
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=32922
Reported-by: Tim Smith <tsmith201104@yahoo.com>
Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/%3Cdaac0eb3af607f72b9a4d3126b2ba8fb5ed3b883.1302820917.git.dvhart%40linux.intel.com%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The case we should be verifying when updating the dentry name is that
the _parent_ inode (the directory) semaphore is held, not the semaphore
for the dentry itself. It's the directory locking that rename and
readdir() etc all care about.
The comment just above even says so - but then the BUG_ON() still
checked the dentry inode itself.
Very few people noticed, because this helper function really isn't used
for very much, so you had to be using ncpfs to ever hit it.
I think I should just remove the BUG_ON (the function really has just
one user), but let's run with it fixed for a while before getting rid of
it entirely.
Reported-and-tested-by: Bongani Hlope <bonganih@bankservafrica.com>
Reported-and-tested-by: Bernd Feige <bernd.feige@uniklinik-freiburg.de>
Cc: Petr Vandrovec <petr@vandrovec.name>,
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
NeilBrown