Commit Graph

25561 Commits

Author SHA1 Message Date
Dave Jones 6764472631 [SELINUX] Fix build after ipsec decap state changes.
security/selinux/xfrm.c: In function 'selinux_socket_getpeer_dgram':
    security/selinux/xfrm.c:284: error: 'struct sec_path' has no member named 'x'
    security/selinux/xfrm.c: In function 'selinux_xfrm_sock_rcv_skb':
    security/selinux/xfrm.c:317: error: 'struct sec_path' has no member named 'x'

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 12:35:53 -07:00
Linus Torvalds 66004a6ca2 Move request_standard_resources() back to before PCI probing
This effectively undoes the PCI resource allocation changes done in
commit b408cbc704, but leaves the cleanups
of that commit in place.

We're going back to marking the resources reported by e820 busy _before_
doing PCI probing, so that any PCI resource that clashes with the BIOS-
reported memory map will be reloacted to a non-clashing area.

The reason? Larry Finger reports that his laptop has the cardbus
controller set up by the BIOS so that it conflicts with the e820 memory
map, and needs to be relocated. See

   http://bugzilla.kernel.org/show_bug.cgi?id=6337

for more details.

We'll have to work out how to handle the fbcon problem that caused that
commit in the first place in some other way.

Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Antonino A. Daplas <adaplas@pol.net>
Cc: <bjk@luxsci.net>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 12:14:02 -07:00
Andi Kleen b8feb47f99 [PATCH] x86_64: Update 32-bit system call table
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:53 -07:00
Andi Kleen 67d53ea5a3 [PATCH] x86_64: Eliminate IA32_NR_syscalls define
Or rather compute it based on the table length automatically.

This also has the intended side effect of not warning for new system calls
anymore.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:53 -07:00
Sam Ravnborg bbd3aff89d [PATCH] x86_64: fix CONFIG_REORDER
Fix CONFIG_REORDER.

The value of cflags-y was assined to CFLAGS before cflags-y was assigned
the value used for CONFIG_REORDER.

Use cflags-y for all CFLAGS options in the Makefile to avoid this
happening again.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:53 -07:00
John Blackwood 97c2803c9c [PATCH] x86_64: Plug GS leak in arch_prctl()
In linux-2.6.16, we have noticed a problem where the gs base value
returned from an arch_prtcl(ARCH_GET_GS, ...) call will be incorrect if:

   - the current/calling task has NOT set its own gs base yet to a
     non-zero value,

   - some other task that ran on the same processor previously set their
     own gs base to a non-zero value.

In this situation, the ARCH_GET_GS code will read and return the
MSR_KERNEL_GS_BASE msr register.

However, since the __switch_to() code does NOT load/zero the
MSR_KERNEL_GS_BASE register when the task that is switched IN has a zero
next->gs value, the caller of arch_prctl(ARCH_GET_GS, ...) will get back
the value of some previous tasks's gs base value instead of 0.

    Change the arch_prctl() ARCH_GET_GS code to only read and return
    the MSR_KERNEL_GS_BASE msr register if the 'gs' register of the calling
    task is non-zero.

    Side note: Since in addition to using arch_prctl(ARCH_SET_GS, ...),
    a task can also setup a gs base value by using modify_ldt() and write
    an index value into 'gs' from user space, the patch below reads
    'gs' instead of using thread.gs, since in the modify_ldt() case,
    the thread.gs value will be 0, and incorrect value would be returned
    (the task->thread.gs value).

    When the user has not set its own gs base value and the 'gs'
    register is zero, then the MSR_KERNEL_GS_BASE register will not be
    read and a value of zero will be returned by reading and returning
    'task->thread.gs'.

    The first patch shown below is an attempt at implementing this
    approach.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:53 -07:00
Andi Kleen e48c4729d2 [PATCH] i386: Remove printk about reboot fixups at reboot
Printk doesn't have any value

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:53 -07:00
Jordan Hargrave b20367a6c2 [PATCH] x86_64: Fix drift with HPET timer enabled
If the HPET timer is enabled, the clock can drift by ~3 seconds a day.
This is due to the HPET timer not being initialized with the correct
setting (still using PIT count).

If HZ changes, this drift can become even more pronounced.

HPET patch initializes tick_nsec with correct tick_nsec settings for
HPET timer.

Vojtech comments:

  "It's not entirely correct (it assumes the HPET ticks totally
   exactly), but it's significantly better than assuming the PIT error
   there."

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:53 -07:00
Andi Kleen 49c93e84d8 [PATCH] i386/x86-64: Return defined error value for bad PCI config space accesses
Mostly to get better handling when a extended config space
access has to fallback to Type1.

Cc: gregkh@suse.de
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:52 -07:00
Andi Kleen 8c30b1a74a [PATCH] i386/x86_64: Check if MCFG works for the first 16 busses
Previously only the first bus would be checked against Type 1.

Why 16? Checking all would need too much memory and we
can assume that systems with more than 16 busses have better than
average quality BIOS.

This is an additional defense against bad MCFG tables.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:52 -07:00
Ravikiran G Thirumalai e405d06729 [PATCH] x86_64: Fixup read_mostly section on internode cache line size for vSMP
Fixup the read mostly section to start at internode cacheline boundary.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:52 -07:00
Andi Kleen 3d34ee6891 [PATCH] x86_64: Don't return error for HPET initialization in initcall
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:52 -07:00
Andi Kleen ac04dcaf6f [PATCH] x86_64: Don't export strlen twice
Fix

  WARNING: vmlinux: 'strlen' exported twice. Previous export was in vmlinux

Reported by Mats Johannesson

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:52 -07:00
Andi Kleen 7bf36bbc5e [PATCH] x86_64: When user could have changed RIP always force IRET
Intel EM64T CPUs handle uncanonical return addresses differently
from AMD CPUs.

The exception is reported in the SYSRET, not the next instruction.
This leads to the kernel exception handler running on the user stack
with the wrong GS because the kernel didn't expect exceptions
on this instruction.

This version of the patch has the teething problems that plagued an earlier
version fixed.

This is CVE-2006-0744

Thanks to Ernie Petrides and Asit B. Mallick for analysis and initial
patches.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:52 -07:00
Andi Kleen 553f265fe8 [PATCH] x86_64: Don't run NMI watchdog during machine checks
Machine checks can stall the machine for a long time and
it's not good to trigger the nmi watchdog during that.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:52 -07:00
Dave Hansen be56db6186 [PATCH] x86_64: extra NODES_SHIFT definition
The generic linux/numa.h file defines NODES_SHIFT to 0 in case
the architecture did not.

Every architecture which has a NUMA config option defines
NODES_SHIFT in its asm-$ARCH headers, but only if NUMA is
enabled, except for x86_64.

This should make it like all the rest.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Jacob Shin 4211a30349 [PATCH] x86_64: Proper null pointer check in powernow_k8_get
This prevents crashes on dual core system when enough ticks are lost.

Replaces earlier patch by me.

Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Andi Kleen d7fa706ce2 [PATCH] x86_64: Revert earlier powernow-k8 change
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Andi Kleen 95d769aaf4 [PATCH] i386: Consolidate modern APIC handling
AMD systems have a modern APIC that supports 8 bit IDs, but
don't have a XAPIC version number.  Add a new "modern_apic"
subfunction that handles this correctly and use it (nearly)
everywhere where XAPIC is tested for.

I removed one wart: the code specified that external APICs
would use an 8bit APIC ID. But I checked a real 82093 data sheet
and it says clearly that they only use 4bit. So I removed
this special case since it would a bit awkward to implement now.

I removed the valid APIC tests in mptable parsing completely. On any modern
system they only check against the full field width (8bit) anyways
and are no-ops. This also fixes them doing the wrong thing
on >8 core Opterons.

This makes i386 boot again on 16 core Opterons.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Andi Kleen d1530d82e0 [PATCH] x86_64: Clear APIC feature bit when local APIC is disabled
Needed for other checks later in ACPI.

Pointed out by Len Brown

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Andi Kleen d3b6a349d2 [PATCH] x86-64/i386: Don't process APICs/IO-APICs in ACPI when APIC is disabled.
When nolapic was passed or the local APIC was disabled
for another reason ACPI would still parse the IO-APICs
until these were explicitely disabled with noapic.

Usually this resulted in a non booting configuration unless
"nolapic noapic" was used.

I also disabled the local APIC parsing in this case, although
that's only cosmetic (suppresses a few printks)

This hopefully makes nolapic work in all cases.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Andi Kleen ec0f08eeea [PATCH] x86_64: Don't sanity check Type 1 PCI bus access on newer systems
Horus systems don't have anything on bus 0 which makes
the Type 1 sanity checks fail.  Use the DMI BIOS year to
check for newer systems and always assume Type 1 works on them.
I used 2001 as an pretty arbitary cutoff year.

Cc: gregkh@suse.de
Cc: Navin Boppuri <navin.boppuri@newisys.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Andi Kleen fa47dd0ba3 [PATCH] x86_64: Fix compilation with CONFIG_PCI=n / allnoconfig
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Arjan van de Ven 946f2ee5c7 [PATCH] i386/x86-64: Check that MCFG points to an e820 reserved area
This patch introduces a user for the e820_all_mapped function:

There have been several machines that don't have a working MMCONFIG,
often because of a buggy MCFG table in the ACPI bios.  This patch adds a
simple sanity check that detects a whole bunch of these cases, and when
it detects it, linux now boots rather than crash-and-burns.

The accuracy of this detection can in principle be improved if there was
a "is this entire range in e820 with THIS attribute", but no such
function exist and the complexity needed for this is not really worth
it; this simple check already catches most cases anyway.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:51 -07:00
Arjan van de Ven 952223683e [PATCH] x86_64: Introduce e820_all_mapped
Introduce a e820_all_mapped() function which checks if the entire range
<start,end> is mapped with type.

This is done by moving the local start variable to the end of each
known-good region; if at the end of the function the start address is
still before end, there must be a part that's not of the correct type;
otherwise it's a good region.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:50 -07:00
Arjan van de Ven eee5a9fa63 [PATCH] x86_64: Rename e820_mapped to e820_any_mapped
Rename e820_mapped to e820_any_mapped since it tests if any part of the
range is mapped according to the type.

Later steps will introduce e820_all_mapped which will check if the
entire range is mapped with the type.  Both have their merit.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:17 -07:00
Andi Kleen a8062231d8 [PATCH] x86_64: Handle empty PXMs that only contain hotplug memory
The node setup code would try to allocate the node metadata in the node
itself, but that fails if there is no memory in there.

This can happen with memory hotplug when the hotplug area defines an so
far empty node.

Now use bootmem to try to allocate the mem_map in other nodes.

And if it fails don't panic, but just ignore the node.

To make this work I added a new __alloc_bootmem_nopanic function that
does what its name implies.

TBD should try to use nearby nodes here.  Currently we just use any.
It's hard to do it better because bootmem doesn't have proper fallback
lists yet.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:16 -07:00
Andi Kleen 68a3a7feb0 [PATCH] x86_64: Reserve SRAT hotadd memory on x86-64
From: Keith Mannthey, Andi Kleen

Implement memory hotadd without sparsemem. The memory in the SRAT
hotadd area is just preserved instead and can be activated later.

There are a few restrictions:
- Only one continuous hotadd area allowed per node

The main problem is dealing with the many buggy SRAT tables
that are out there. The strategy here is to reject anything
suspicious.

Originally from Keith Mannthey, with several hacks and changes by AK
and also contributions from Andrew Morton

[ TBD: Problems pointed out by KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>:

 1) Goto's rebuild_zonelist patch will not work if CONFIG_MEMORY_HOTPLUG=n.

    Rebuilding zonelist is necessary when the system has just memory <
    4G at boot, and hot add memory > 4G.  because x86_64 has DMA32,
    ZONE_NORAML is not included into zonelist at boot time if system
    doesn't have memory >4G at boot.

    [AK: should just force the higher zones at boot time when SRAT tells us]

 2) zone and node's spanned_pages and present_pages are not incremented.
    They should be.

    For example, our server (ia64/Fujitsu PrimeQuest) can equip memory
    from 4G to 1T(maybe 2T in future), and SRAT will *always* say we have
    possible 1T +memory.  (Microsoft requires "write all possible memory
    in SRAT") When we reserve memmap for possible 1T memory, Linux will
    not work well in +minimum 4G configuraion ;)

    [AK: needs limiting to 5-10% of max memory]
 ]

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:16 -07:00
Andi Kleen 9d99aaa31f [PATCH] x86_64: Support memory hotadd without sparsemem
Memory hotadd doesn't need SPARSEMEM, but can be handled by just preallocating
mem_maps. This only needs some untangling of ifdefs to enable the necessary
code even without SPARSEMEM.

Originally from Keith Mannthey, hacked by AK.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:16 -07:00
Andi Kleen 805e8c03c9 [PATCH] x86_64: Clean up execve path
Just call IRET always, no need for any special cases.

Needed for the next bug fix.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:16 -07:00
Andi Kleen 903fcc608e [PATCH] x86_64: Update defconfig
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:16 -07:00
Russell King c5b8ef62b5 [ARM] Allow decompressor to be built with -ffunction-sections
Arrange for all the text ends up in the right place when
-ffunction-sections is used.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-04-09 19:08:42 +01:00
Mark Fasheh a9e2ae3917 ocfs2: Better I/O error handling in heartbeat
Propagate errors received in o2hb_bio_end_io() back to the heartbeat thread
so it can skip re-arming the timer.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-04-07 18:03:09 -07:00
Mark Fasheh 2cd9888590 ocfs2: test and set teardown flag early in user_dlm_destroy_lock()
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-04-07 17:39:43 -07:00
Mark Fasheh f43e6918c0 ocfs2: Handle the DLM_CANCELGRANT case in user_unlock_ast()
Remove the code which attempted to catch it via dlmunlock() return status -
this never happens there.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-04-07 17:37:52 -07:00
Mark Fasheh cc6eb72595 ocfs2: catch an invalid ast case in dlmfs
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-04-07 17:36:16 -07:00
Mark Fasheh 1f7bc828e3 ocfs2: remove an overly aggressive BUG() in dlmfs
Don't BUG() user_dlm_unblock_lock() on the absence of the USER_LOCK_BLOCKED
flag - this turns out to be a valid case. Make some of the related BUG()
statements print more useful information.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-04-07 17:27:43 -07:00
Mark Fasheh ab0920ce7e ocfs2: multi node truncate fix
Fix ocfs2_truncate_file() so that it forces a truncate_inode_pages() on all
interested nodes in all cases of a truncate(), not just allocation change.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-04-07 16:47:24 -07:00
Russell King 95f3df6bcb [ARM] Fix SA110/SA1100 cache flushing
We had two implementations for flushing the cache, which meant StrongARM
caches weren't being correctly flushed.  Fix this by always using the
v4wb_flush_kern_cache_all method, rather than duplicating it.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-04-07 13:23:57 +01:00
Russell King f1dc24d53e [ARM] ebsa110: Fix incorrect serial port address
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-04-07 13:23:48 +01:00
Russell King 6e29ebad0f [ARM] Fix ebsa110 debug macros
Was including debug-8250.h rather than debug-8250.S

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-04-07 13:23:37 +01:00
Russell King 74d02fb954 [ARM] Move FLUSH_BASE macros to asm/arch/memory.h
FLUSH_BASE must be visible to arch/arm/mm/init.c in order for the
memory region to be setup.  Move these definitions from
asm-arm/arch-*/hardware.h into asm-arm/arch-*/memory.h where mm
stuff can see them.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-04-07 13:22:21 +01:00
Russell King 7d12963757 [ARM] Remove unnecessary extra parens in include/asm-arm/memory.h
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-04-04 16:25:47 +01:00
KAMEZAWA Hiroyuki 0da323505f [ARM] arm's arch_local_page_offset() fix against 2.6.17-rc1
This patch fixes arch_local_page_offset(pfn,nid) in arm.
This new one (added by unify_pfn_to_page patches) is obviously buggy.

This macro calculate page offset in a node.

Note: about LOCAL_MAP_NR()
comment in arm's sub-archs says...

 /*
  * Given a kaddr, LOCAL_MAP_NR finds the owning node of the memory
  * and returns the index corresponding to the appropriate page in the
  * node's mem_map.
  */

but LOCAL_MAP_NR() is designed to be able to take both paddr and kaddr.
In this case, paddr is better.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitu.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-04-04 16:06:00 +01:00
Linus Torvalds 6246b6128b Linux v2.6.17-rc1
Close of the merge window..
2006-04-02 20:22:10 -07:00
Linus Torvalds 6fdb94bd95 Update dummy snd_power_wait() function for new calling convention
Apparently nobody had tried to compile the ALSA CVS tree without power
management enabled.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-02 14:37:36 -07:00
Linus Torvalds d69636157a Merge branch 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block
* 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] splice: fix page stealing LRU handling.
  [PATCH] splice: page stealing needs to wait_on_page_writeback()
  [PATCH] splice: export generic_splice_sendpage
  [PATCH] splice: add a SPLICE_F_MORE flag
  [PATCH] splice: add comments documenting more of the code
  [PATCH] splice: improve writeback and clean up page stealing
  [PATCH] splice: fix shadow[] filling logic
2006-04-02 14:22:06 -07:00
Jens Axboe 3e7ee3e7b3 [PATCH] splice: fix page stealing LRU handling.
Originally from Nick Piggin, just adapted to the newer branch.

You can't check PageLRU without holding zone->lru_lock.  The page
release code can get away with it only because the page refcount is 0 at
that point. Also, you can't reliably remove pages from the LRU unless
the refcount is 0. Ever.

Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-02 23:11:04 +02:00
Jens Axboe ad8d6f0a78 [PATCH] splice: page stealing needs to wait_on_page_writeback()
Thanks to Andrew for the good explanation of why this is so. akpm writes:

If a page is under writeback and we remove it from pagecache, it's still
going to get written to disk.  But the VFS no longer knows about that page,
nor that this page is about to modify disk blocks.

So there might be scenarios in which those
blocks-which-are-about-to-be-written-to get reused for something else.
When writeback completes, it'll scribble on those blocks.

This won't happen in ext2/ext3-style filesystems in normal mode because the
page has buffers and try_to_release_page() will fail.

But ext2 in nobh mode doesn't attach buffers at all - it just sticks the
page in a BIO, finds some new blocks, points the BIO at those blocks and
lets it rip.

While that write IO's in flight, someone could truncate the file.  Truncate
won't block on the writeout because the page isn't in pagecache any more.
So truncate will the free the blocks from the file under the page's feet.
Then something else can reallocate those blocks.  Then write data to them.

Now, the original write completes, corrupting the filesystem.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-02 23:10:32 +02:00
Jens Axboe 059a8f3734 [PATCH] splice: export generic_splice_sendpage
Forgot that one, thanks Jeff. Also move the other EXPORT_SYMBOL
to right below the functions.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-02 23:06:05 +02:00