linux-toradex.git/fs/jbd2/commit.c, branch v3.10.2

jbd2: fix race between jbd2_journal_remove_checkpoint and ->j_commit_callback

2013-04-04T02:06:52+00:00

The following race is possible:

[kjournald2]                              other_task
jbd2_journal_commit_transaction()
  j_state = T_FINISHED;
  spin_unlock(&journal->j_list_lock);
                                         ->jbd2_journal_remove_checkpoint()
					   ->jbd2_journal_free_transaction();
					     ->kmem_cache_free(transaction)
  ->j_commit_callback(journal, transaction);
    -> USE_AFTER_FREE

WARNING: at lib/list_debug.c:62 __list_del_entry+0x1c0/0x250()
Hardware name:
list_del corruption. prev->next should be ffff88019a4ec198, but was 6b6b6b6b6b6b6b6b
Modules linked in: cpufreq_ondemand acpi_cpufreq freq_table mperf coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode sg xhci_hcd button sd_mod crc_t10dif aesni_intel ablk_helper cryptd lrw aes_x86_64 xts gf128mul ahci libahci pata_acpi ata_generic dm_mirror dm_region_hash dm_log dm_mod
Pid: 16400, comm: jbd2/dm-1-8 Tainted: G        W    3.8.0-rc3+ #107
Call Trace:
 [] warn_slowpath_common+0xad/0xf0
 [] warn_slowpath_fmt+0x46/0x50
 [] ? ext4_journal_commit_callback+0x99/0xc0
 [] __list_del_entry+0x1c0/0x250
 [] ext4_journal_commit_callback+0x6f/0xc0
 [] jbd2_journal_commit_transaction+0x23a6/0x2570
 [] ? try_to_del_timer_sync+0x82/0xa0
 [] ? del_timer_sync+0x91/0x1e0
 [] kjournald2+0x19f/0x6a0
 [] ? wake_up_bit+0x40/0x40
 [] ? bit_spin_lock+0x80/0x80
 [] kthread+0x10e/0x120
 [] ? __init_kthread_worker+0x70/0x70
 [] ret_from_fork+0x7c/0xb0
 [] ? __init_kthread_worker+0x70/0x70

In order to demonstrace this issue one should mount ext4 with mount -o
discard option on SSD disk.  This makes callback longer and race
window becomes wider.

In order to fix this we should mark transaction as finished only after
callbacks have completed

Signed-off-by: Dmitry Monakhov 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@vger.kernel.org

jbd2: track request delay statistics

2013-02-07T03:30:23+00:00

Track the delay between when we first request that the commit begin
and when it actually begins, so we can see how much of a gap exists.
In theory, this should just be the remaining scheduling quantuum of
the thread which requested the commit (assuming it was not a
synchronous operation which triggered the commit request) plus
scheduling overhead; however, it's possible that real time processes
might get in the way of letting the kjournald thread from executing.

Signed-off-by: "Theodore Ts'o"

jbd2: fix assertion failure in commit code due to lacking transaction credits

2012-09-27T03:11:13+00:00

ext4 users of data=journal mode with blocksize < pagesize were
occasionally hitting assertion failure in
jbd2_journal_commit_transaction() checking whether the transaction has
at least as many credits reserved as buffers attached.  The core of the
problem is that when a file gets truncated, buffers that still need
checkpointing or that are attached to the committing transaction are
left with buffer_mapped set. When this happens to buffers beyond i_size
attached to a page stradding i_size, subsequent write extending the file
will see these buffers and as they are mapped (but underlying blocks
were freed) things go awry from here.

The assertion failure just coincidentally (and in this case luckily as
we would start corrupting filesystem) triggers due to journal_head not
being properly cleaned up as well.

We fix the problem by unmapping buffers if possible (in lots of cases we
just need a buffer attached to a transaction as a place holder but it
must not be written out anyway).  And in one case, we just have to bite
the bullet and wait for transaction commit to finish.

CC: Josef Bacik 
Signed-off-by: Jan Kara

jbd2: remove the second argument of kmap_atomic

2012-07-23T06:11:22+00:00

Signed-off-by: Cong Wang

jbd2: checksum data blocks that are stored in the journal

2012-05-27T12:12:12+00:00

Calculate and verify checksums of each data block being stored in the journal.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"

jbd2: checksum commit blocks

2012-05-27T12:10:25+00:00

Calculate and verify the checksum of commit blocks.  In checksum v2,
deprecate most of the checksum v1 commit block checksum fields, since
each block has its own checksum.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"

jbd2: checksum descriptor blocks

2012-05-27T12:10:22+00:00

Calculate and verify a checksum of each descriptor block.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"

jbd2: change disk layout for metadata checksumming

2012-05-23T02:43:41+00:00

Define flags and allocate space in on-disk journal structures to support
checksumming of journal metadata.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"

jbd2: use GFP_NOFS for blkdev_issue_flush

2012-04-24T01:43:41+00:00

flush request is issued in transaction commit code path, so looks using
GFP_KERNEL to allocate memory for flush request bio falls into the classic
deadlock issue.  I saw btrfs and dm get it right, but ext4, xfs and md are
using GFP.

Signed-off-by: Shaohua Li 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara 
Cc: stable@vger.kernel.org

Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system

2012-03-28T22:58:21+00:00

Pull "Disintegrate and delete asm/system.h" from David Howells:
 "Here are a bunch of patches to disintegrate asm/system.h into a set of
  separate bits to relieve the problem of circular inclusion
  dependencies.

  I've built all the working defconfigs from all the arches that I can
  and made sure that they don't break.

  The reason for these patches is that I recently encountered a circular
  dependency problem that came about when I produced some patches to
  optimise get_order() by rewriting it to use ilog2().

  This uses bitops - and on the SH arch asm/bitops.h drags in
  asm-generic/get_order.h by a circuituous route involving asm/system.h.

  The main difficulty seems to be asm/system.h.  It holds a number of
  low level bits with no/few dependencies that are commonly used (eg.
  memory barriers) and a number of bits with more dependencies that
  aren't used in many places (eg.  switch_to()).

  These patches break asm/system.h up into the following core pieces:

    (1) asm/barrier.h

        Move memory barriers here.  This already done for MIPS and Alpha.

    (2) asm/switch_to.h

        Move switch_to() and related stuff here.

    (3) asm/exec.h

        Move arch_align_stack() here.  Other process execution related bits
        could perhaps go here from asm/processor.h.

    (4) asm/cmpxchg.h

        Move xchg() and cmpxchg() here as they're full word atomic ops and
        frequently used by atomic_xchg() and atomic_cmpxchg().

    (5) asm/bug.h

        Move die() and related bits.

    (6) asm/auxvec.h

        Move AT_VECTOR_SIZE_ARCH here.

  Other arch headers are created as needed on a per-arch basis."

Fixed up some conflicts from other header file cleanups and moving code
around that has happened in the meantime, so David's testing is somewhat
weakened by that.  We'll find out anything that got broken and fix it..

* tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits)
  Delete all instances of asm/system.h
  Remove all #inclusions of asm/system.h
  Add #includes needed to permit the removal of asm/system.h
  Move all declarations of free_initmem() to linux/mm.h
  Disintegrate asm/system.h for OpenRISC
  Split arch_align_stack() out from asm-generic/system.h
  Split the switch_to() wrapper out of asm-generic/system.h
  Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
  Create asm-generic/barrier.h
  Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h
  Disintegrate asm/system.h for Xtensa
  Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt]
  Disintegrate asm/system.h for Tile
  Disintegrate asm/system.h for Sparc
  Disintegrate asm/system.h for SH
  Disintegrate asm/system.h for Score
  Disintegrate asm/system.h for S390
  Disintegrate asm/system.h for PowerPC
  Disintegrate asm/system.h for PA-RISC
  Disintegrate asm/system.h for MN10300
  ...