nilfs2: fix segctor bug that causes file system corruption

There is a bug in the function nilfs_segctor_collect, which results in
active data being written to a segment, that is marked as clean.  It is
possible, that this segment is selected for a later segment
construction, whereby the old data is overwritten.

The problem shows itself with the following kernel log message:

  nilfs_sufile_do_cancel_free: segment 6533 must be clean

Usually a few hours later the file system gets corrupted:

  NILFS: bad btree node (blocknr=8748107): level = 0, flags = 0x0, nchildren = 0
  NILFS error (device sdc1): nilfs_bmap_last_key: broken bmap (inode number=114660)

The issue can be reproduced with a file system that is nearly full and
with the cleaner running, while some IO intensive task is running.
Although it is quite hard to reproduce.

This is what happens:

 1. The cleaner starts the segment construction
 2. nilfs_segctor_collect is called
 3. sc_stage is on NILFS_ST_SUFILE and segments are freed
 4. sc_stage is on NILFS_ST_DAT current segment is full
 5. nilfs_segctor_extend_segments is called, which
    allocates a new segment
 6. The new segment is one of the segments freed in step 3
 7. nilfs_sufile_cancel_freev is called and produces an error message
 8. Loop around and the collection starts again
 9. sc_stage is on NILFS_ST_SUFILE and segments are freed
    including the newly allocated segment, which will contain active
    data and can be allocated at a later time
10. A few hours later another segment construction allocates the
    segment and causes file system corruption

This can be prevented by simply reordering the statements.  If
nilfs_sufile_cancel_freev is called before nilfs_segctor_extend_segments
the freed segments are marked as dirty and cannot be allocated any more.

Signed-off-by: Andreas Rohner <andreas.rohner@gmx.net>
Reviewed-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Andreas Rohner <andreas.rohner@gmx.net>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MIPS: fix case mismatch in local_r4k_flush_icache_range()

Currently, Loongson-2 call protected_blast_icache_range() and others
call protected_loongson23_blast_icache_range(), but I think the correct
behavior should be the opposite.  BTW, Loongson-3's cache-ops is
compatible with MIPS64, but not compatible with Loongson-2.  So, rename
xxx_loongson23_yyy things to xxx_loongson2_yyy.

The patch fixes early boot hang with 3.13-rc1, introduced in commit
14bd8c082016 ("MIPS: Loongson: Get rid of Loongson 2 #ifdefery all over
arch/mips").

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: John Crispin <blogic@openwrt.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MIPS: fix blast_icache32 on loongson2

Commit 14bd8c082016 ("MIPS: Loongson: Get rid of Loongson 2 #ifdefery
all over arch/mips") failed to add Loongson2 specific blast_icache32
functions.  Fix that.

The patch fixes the following crash seen with 3.13-rc1:

  Reserved instruction in kernel code[#1]:
  [...]
  Call Trace:
    blast_icache32_page+0x8/0xb0
    r4k_flush_cache_page+0x19c/0x200
    do_wp_page.isra.97+0x47c/0xe08
    handle_mm_fault+0x938/0x1118
    __do_page_fault+0x140/0x540
    resume_userspace_check+0x0/0x10
  Code: 00200825  64834000  00200825 <bc900000> bc900020  bc900040  bc900060  bc900080  bc9000a0

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: John Crispin <blogic@openwrt.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: fix crash when using XFS on loopback

Commit 8456a648cf44 ("slab: use struct page for slab management") causes
a crash in the LVM2 testsuite on PA-RISC (the crashing test is
fsadm.sh).  The testsuite doesn't crash on 3.12, crashes on 3.13-rc1 and
later.

 Bad Address (null pointer deref?): Code=15 regs=000000413edd89a0 (Addr=000006202224647d)
 CPU: 3 PID: 24008 Comm: loop0 Not tainted 3.13.0-rc6 #5
 task: 00000001bf3c0048 ti: 000000413edd8000 task.ti: 000000413edd8000

      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
 PSW: 00001000000001101111100100001110 Not tainted
 r00-03  000000ff0806f90e 00000000405c8de0 000000004013e6c0 000000413edd83f0
 r04-07  00000000405a95e0 0000000000000200 00000001414735f0 00000001bf349e40
 r08-11  0000000010fe3d10 0000000000000001 00000040829c7778 000000413efd9000
 r12-15  0000000000000000 000000004060d800 0000000010fe3000 0000000010fe3000
 r16-19  000000413edd82a0 00000041078ddbc0 0000000000000010 0000000000000001
 r20-23  0008f3d0d83a8000 0000000000000000 00000040829c7778 0000000000000080
 r24-27  00000001bf349e40 00000001bf349e40 202d66202224640d 00000000405a95e0
 r28-31  202d662022246465 000000413edd88f0 000000413edd89a0 0000000000000001
 sr00-03  000000000532c000 0000000000000000 0000000000000000 000000000532c000
 sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000401fe42c 00000000401fe430
  IIR: 539c0030    ISR: 00000000202d6000  IOR: 000006202224647d
  CPU:        3   CR30: 000000413edd8000 CR31: 0000000000000000
  ORIG_R28: 00000000405a95e0
  IAOQ[0]: vma_interval_tree_iter_first+0x14/0x48
  IAOQ[1]: vma_interval_tree_iter_first+0x18/0x48
  RP(r2): flush_dcache_page+0x128/0x388
 Backtrace:
   flush_dcache_page+0x128/0x388
   lo_splice_actor+0x90/0x148 [loop]
   splice_from_pipe_feed+0xc0/0x1d0
   __splice_from_pipe+0xac/0xc0
   lo_direct_splice_actor+0x1c/0x70 [loop]
   splice_direct_to_actor+0xec/0x228
   lo_receive+0xe4/0x298 [loop]
   loop_thread+0x478/0x640 [loop]
   kthread+0x134/0x168
   end_fault_vector+0x20/0x28
   xfs_setsize_buftarg+0x0/0x90 [xfs]

 Kernel panic - not syncing: Bad Address (null pointer deref?)

Commit 8456a648cf44 changes the page structure so that the slab
subsystem reuses the page->mapping field.

The crash happens in the following way:
 * XFS allocates some memory from slab and issues a bio to read data
   into it.
 * the bio is sent to the loopback device.
 * lo_receive creates an actor and calls splice_direct_to_actor.
 * lo_splice_actor copies data to the target page.
 * lo_splice_actor calls flush_dcache_page because the page may be
   mapped by userspace.  In that case we need to flush the kernel cache.
 * flush_dcache_page asks for the list of userspace mappings, however
   that page->mapping field is reused by the slab subsystem for a
   different purpose.  This causes the crash.

Note that other architectures without coherent caches (sparc, arm, mips)
also call page_mapping from flush_dcache_page, so they may crash in the
same way.

This patch fixes this bug by testing if the page is a slab page in
page_mapping and returning NULL if it is.

The patch also fixes VM_BUG_ON(PageSlab(page)) that could happen in
earlier kernels in the same scenario on architectures without cache
coherence when CONFIG_DEBUG_VM is enabled - so it should be backported
to stable kernels.

In the old kernels, the function page_mapping is placed in
include/linux/mm.h, so you should modify the patch accordingly when
backporting it.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: John David Anglin <dave.anglin@bell.net>]
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
crash_dump: fix compilation error (on MIPS at least)

  In file included from kernel/crash_dump.c:2:0:
  include/linux/crash_dump.h:22:27: error: unknown type name `pgprot_t'

when CONFIG_CRASH_DUMP=y

The error was traced back to commit 9cb218131de1 ("vmcore: introduce
remap_oldmem_pfn_range()")

include <asm/pgtable.h> to get the missing definition

Signed-off-by: Qais Yousef <qais.yousef@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: <stable@vger.kernel.org>	[3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/percpu_counter.c: fix __percpu_counter_add()

__percpu_counter_add() may be called in softirq/hardirq handler (such
as, blk_mq_queue_exit() is typically called in hardirq/softirq handler),
so we need to call this_cpu_add()(irq safe helper) to update percpu
counter, otherwise counts may be lost.

This fixes the problem that 'rmmod null_blk' hangs in blk_cleanup_queue()
because of miscounting of request_queue->mq_usage_counter.

This patch is the v1 of previous one of "lib/percpu_counter.c:
disable local irq when updating percpu couter", and takes Andrew's
approach which may be more efficient for ARCHs(x86, s390) that
have optimized this_cpu_add().

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Shaohua Li <shli@fusionio.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Fan Du <fan.du@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'akpm' (incoming from Andrew)

Merge patches from Andrew Morton:
 "Six fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  lib/percpu_counter.c: fix __percpu_counter_add()
  crash_dump: fix compilation error (on MIPS at least)
  mm: fix crash when using XFS on loopback
  MIPS: fix blast_icache32 on loongson2
  MIPS: fix case mismatch in local_r4k_flush_icache_range()
  nilfs2: fix segctor bug that causes file system corruption