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  1. 29 Dec, 2006 1 commit
    • Linus Torvalds's avatar
      VM: Fix nasty and subtle race in shared mmap'ed page writeback · 7658cc28
      Linus Torvalds authored 
      The VM layer (on the face of it, fairly reasonably) expected that when
it does a ->writepage() call to the filesystem, it would write out the
full page at that point in time.  Especially since it had earlier marked
the whole page dirty with "set_page_dirty()".

But that isn't actually the case: ->writepage() does not actually write
a page, it writes the parts of the page that have been explicitly marked
dirty before, *and* that had not got written out for other reasons since
the last time we told it they were dirty.

That last caveat is the important one.

Which _most_ of the time ends up being the whole page (since we had
called "set_page_dirty()" on the page earlier), but if the filesystem
had done any dirty flushing of its own (for example, to honor some
internal write ordering guarantees), it might end up doing only a
partial page IO (or none at all) when ->writepage() is actually called.

That is the correct thing in general (since we actually often _want_
only the known-dirty parts of the page to be written out), but the
shared dirty page handling had implicitly forgotten about these details,
and had a number of cases where it was doing just the "->writepage()"
part, without telling the low-level filesystem that the whole page might
have been re-dirtied as part of being mapped writably into user space.

Since most of the time the FS did actually write out the full page, we
didn't notice this for a loong time, and this needed some really odd
patterns to trigger.  But it caused occasional corruption with rtorrent
and with the Debian "apt" database, because both use shared mmaps to
update the end result.

This fixes it. Finally. After way too much hair-pulling.
Acked-by: default avatarNick Piggin <nickpiggin@yahoo.com.au>
Acked-by: default avatarMartin J. Bligh <mbligh@google.com>
Acked-by: default avatarMartin Michlmayr <tbm@cyrius.com>
Acked-by: default avatarMartin Johansson <martin@fatbob.nu>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Acked-by: default avatarAndrei Popa <andrei.popa@i-neo.ro>
Cc: High Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@osdl.org>,
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Gordon Farquharson <gordonfarquharson@gmail.com>
Cc: Guillaume Chazarain <guichaz@yahoo.fr>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Kenneth Cheng <kenneth.w.chen@intel.com>
Cc: Tobias Diedrich <ranma@tdiedrich.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      7658cc28
  3. 24 Dec, 2006 2 commits
  5. 23 Dec, 2006 5 commits
    • OGAWA Hirofumi's avatar
      [PATCH] arch/i386/pci/mmconfig.c tlb flush fix · 8d1c4819
      OGAWA Hirofumi authored 
      We use the fixmap for accessing pci config space in pci_mmcfg_read/write().
The problem is in pci_exp_set_dev_base(). It is caching a last
accessed address to avoid calling set_fixmap_nocache() whenever
pci_mmcfg_read/write() is used.

  static inline void pci_exp_set_dev_base(int bus, int devfn)
  {
	u32 dev_base = base | (bus << 20) | (devfn << 12);
	if (dev_base != mmcfg_last_accessed_device) {
		mmcfg_last_accessed_device = dev_base;
		set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
	}
  }

            cpu0                                        cpu1
  ---------------------------------------------------------------------------
    pci_mmcfg_read("device-A")
        pci_exp_set_dev_base()
            set_fixmap_nocache()
                                              pci_mmcfg_read("device-B")
                                                  pci_exp_set_dev_base()
                                                      set_fixmap_nocache()
    pci_mmcfg_read("device-B")
        pci_exp_set_dev_base()
            /* doesn't flush tlb */

But if cpus accessed the above order, the second pci_mmcfg_read() on
cpu0 doesn't flush the TLB, because "mmcfg_last_accessed_device" is
device-B.  So, second pci_mmcfg_read() on cpu0 accesses a device-A via
a previous TLB cache. This problem became the cause of several strange
behavior.

This patches fixes this situation by adds "mmcfg_last_accessed_cpu" check.

[ Alternatively, we could make a per-cpu mapping area or something. Not
  that it's probably worth it, but if we wanted to avoid all locking and
  instead just disable preemption, that would be the way to go. --Linus ]
Signed-off-by: default avatarOGAWA Hirofumi <hogawa@miraclelinux.com>
Signed-off-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      8d1c4819
    • Ingo Molnar's avatar
      [PATCH] suspend: fix suspend on single-CPU systems · e1d9fd2e
      Ingo Molnar authored 
      Clark Williams reported that suspend doesnt work on his laptop on
2.6.20-rc1-rt kernels. The bug was introduced by the following cleanup
commit:

 commit 112cecb2
 Author: Siddha, Suresh B <suresh.b.siddha@intel.com>
 Date:   Wed Dec 6 20:34:31 2006 -0800

    [PATCH] suspend: don't change cpus_allowed for task initiating the suspend

because with this change 'error' is not initialized to 0 anymore, if
there are no other online CPUs. (i.e. if the system is single-CPU).

the fix is the initialize it to 0. The really weird thing is that my
version of gcc does not warn about this non-initialized variable
situation ...

(also fix the kernel printk in the error branch, it was missing a
 newline)
Reported-by: default avatarClark Williams <williams@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      e1d9fd2e
    • Linus Torvalds's avatar
      Fix reiserfs after "test_clear_page_dirty()" removal · ffaa8200
      Linus Torvalds authored 
      Thanks to Len Brown for testing this fix, since while they have in the
past, none of my machines run reiserfs at the moment.

Cc: Vladimir V. Saveliev <vs@namesys.com>
Acked-by: default avatarLen Brown <lenb@kernel.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      ffaa8200
    • Linus Torvalds's avatar
      Clean up and export cancel_dirty_page() to modules · 8368e328
      Linus Torvalds authored 
      Make cancel_dirty_page() act more like all the other dirty and writeback
accounting functions: test for "mapping" being NULL, and do the
NR_FILE_DIRY accounting purely based on mapping_cap_account_dirty()).

Also, add it to the exports, so that modular filesystems can use it.
Acked-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      8368e328
    • Linus Torvalds's avatar
      Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 · 18ed1c05
      Linus Torvalds authored 
      * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (68 commits)
  ACPI: replace kmalloc+memset with kzalloc
  ACPI: Add support for acpi_load_table/acpi_unload_table_id
  fbdev: update after backlight argument change
  ACPI: video: Add dev argument for backlight_device_register
  ACPI: Implement acpi_video_get_next_level()
  ACPI: Kconfig - depend on PM rather than selecting it
  ACPI: fix NULL check in drivers/acpi/osl.c
  ACPI: make drivers/acpi/ec.c:ec_ecdt static
  ACPI: prevent processor module from loading on failures
  ACPI: fix single linked list manipulation
  ACPI: ibm_acpi: allow clean removal
  ACPI: fix git automerge failure
  ACPI: ibm_acpi: respond to workqueue update
  ACPI: dock: add uevent to indicate change in device status
  ACPI: ec: Lindent once again
  ACPI: ec: Change #define to enums there possible.
  ACPI: ec: Style changes.
  ACPI: ec: Acquire Global Lock under EC mutex.
  ACPI: ec: Drop udelay() from poll mode. Loop by reading status field instead.
  ACPI: ec: Rename gpe_bit to gpe
  ...
      18ed1c05
  7. 22 Dec, 2006 32 commits