04 Jul, 2011

5 commits

  • This is a clean-up of the power-cut emulation code - remove the custom list of
    superblocks which we maintained to find the superblock by the UBI volume
    descriptor. We do not need that crud any longer, because now we can get the
    superblock as a function argument.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     
  • Stop using 'ubi_leb_write()' directly and switch to the 'ubifs_leb_write()'
    helper.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     
  • Instead of using 'ubi_read()' function directly, used the 'ubifs_leb_read()'
    helper function instead. This allows to get rid of several redundant error
    messages and make sure that we always have a stack dump on read errors.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     
  • Introduce the following I/O helper functions: 'ubifs_leb_read()',
    'ubifs_leb_write()', 'ubifs_leb_change()', 'ubifs_leb_unmap()',
    'ubifs_leb_map()', 'ubifs_is_mapped().

    The idea is to wrap all UBI I/O functions in order to encapsulate various
    assertions and error path handling (error message, stack dump, switching to R/O
    mode). And there are some other benefits of this which will be used in the
    following patches.

    This patch does not switch whole UBIFS to use these functions yet.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     
  • When switching to R/O mode due to an I/O error, always dump the stack, not only
    when debugging is enabled.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

03 Jun, 2011

1 commit

  • The current free space fixup can result in some writing to the UBI volume
    when the space_fixup flag is set.

    To catch instances where UBIFS is writing to the NAND while the space_fixup
    flag is set, add an assert to ubifs_write_node().

    Artem: tweaked the patch, added similar assertion to the write buffer
    write path.

    Signed-off-by: Ben Gardiner
    Reviewed-by: Matthew L. Creech
    Signed-off-by: Artem Bityutskiy

    Ben Gardiner
     

16 May, 2011

2 commits

  • Currently when UBIFS fills up the current bud (which is the last in the journal
    head) and switches to the next bud, it first writes the log reference node for
    the next bud and only after this synchronizes the write-buffer of the previous
    bud. This is not a big deal, but an unclean power cut may lead to a situation
    when we have corruption in a next-to-last bud, although it is much more logical
    that we have to have corruption only in the last bud.

    This patch also removes write-buffer synchronization from
    'ubifs_wbuf_seek_nolock()' because this is not needed anymore (we synchronize
    the write-buffer explicitly everywhere now) and also because this is just
    prone to various errors.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     
  • This is patch removes an unnecessary 'offs' variable from 'ubifs_wbuf_write_nolock()'
    - we can just keep 'wbuf->offs' up-to-date instead. This patch is very minor
    the only motivation for it was that it is cleaner to keep wbuf->offs up-to-date
    by the time we call 'ubifs_leb_write()'.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

14 May, 2011

1 commit


08 Mar, 2011

2 commits

  • Switch write-buffers from 'c->min_io_size' to 'c->max_write_size' which
    presumably has to be more write speed-efficient. However, when write-buffer
    is synchronized, write only the the min. I/O units which contain the
    data, do not write whole write-buffer. This is more space-efficient.

    Additionally, this patch takes into account that the LEB might not start
    from the max. write unit-aligned address.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     
  • Currently we assume write-buffer size is always min_io_size. But
    this is about to change and write-buffers may be of variable size.
    Namely, they will be of max_write_size at the beginning, but will
    get smaller when we are approaching the end of LEB.

    This is a preparation patch which introduces 'size' field in
    the write-buffer structure which carries the current write-buffer
    size.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

18 Jan, 2011

1 commit

  • This is a preparational patch which removes the 'c->always_chk_crc' which was
    set during mounting and remounting to R/W mode and introduces 'c->mounting'
    flag which is set when mounting. Now the 'c->always_chk_crc' flag is the
    same as 'c->remounting_rw && c->mounting'.

    This patch is a preparation for the next one which will need to know when we
    are mounting and remounting to R/W mode, which is exactly what
    'c->always_chk_crc' effectively is, but its name does not suite the
    next patch. The other possibility would be to just re-name it, but then
    we'd end up with less logical flags coverage.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

20 Sep, 2010

1 commit

  • Commit 2fde99cb55fb9d9b88180512a5e8a5d939d27fec "UBIFS: mark VFS SB RO too"
    introduced regression. This commit made UBIFS set the 'MS_RDONLY' flag in the
    VFS superblock when it switches to R/O mode due to an error. This was done
    to make VFS show the R/O UBIFS flag in /proc/mounts.

    However, several places in UBIFS relied on the 'MS_RDONLY' flag and assume this
    flag can only change when we re-mount. For example, 'ubifs_put_super()'.

    This patch introduces new UBIFS flag - 'c->ro_mount' which changes only when
    we re-mount, and preserves the way UBIFS was originally mounted (R/W or R/O).
    This allows us to de-initialize UBIFS cleanly in 'ubifs_put_super()'.

    This patch also changes all 'ubifs_assert(!c->ro_media)' assertions to
    'ubifs_assert(!c->ro_media && !c->ro_mount)', because we never should write
    anything if the FS was mounter R/O.

    All the places where we test for 'MS_RDONLY' flag in the VFS SB were changed
    and now we test the 'c->ro_mount' flag instead, because it preserves the
    original UBIFS mount type, unlike the 'MS_RDONLY' flag.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

17 Sep, 2010

1 commit

  • The R/O state may have various reasons:

    1. The UBI volume is R/O
    2. The FS is mounted R/O
    3. The FS switched to R/O mode because of an error

    However, in UBIFS we have only one variable which represents cases
    1 and 3 - 'c->ro_media'. Indeed, we set this to 1 if we switch to
    R/O mode due to an error, and then we test it in many places to
    make sure that we stop writing as soon as the error happens.

    But this is very unclean. One consequence of this, for example, is
    that in 'ubifs_remount_fs()' we use 'c->ro_media' to check whether
    we are in R/O mode because on an error, and we print a message
    in this case. However, if we are in R/O mode because the media
    is R/O, our message is bogus.

    This patch introduces new flag - 'c->ro_error' which is set when
    we switch to R/O mode because of an error. It also changes all
    "if (c->ro_media)" checks to "if (c->ro_error)" checks, because
    this is what the checks actually mean. We do not need to check
    for 'c->ro_media' because if the UBI volume is in R/O mode, we
    do not allow R/W mounting, and now writes can happen. This is
    guaranteed by VFS. But it is good to double-check this, so this
    patch also adds many "ubifs_assert(!c->ro_media)" checks.

    In the 'ubifs_remount_fs()' function this patch makes a bit more
    changes - it fixes the error messages as well.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

30 Aug, 2010

1 commit


29 Apr, 2010

1 commit

  • If some read/write error happens (eg.CRC error), UBIFS swotches to
    read-only mode, but the VFS infomation still not update.
    This patch add this also make /proc/mounts update.

    Signed-off-by: Zhang Jiejing

    ZhangJieJing
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

15 Sep, 2009

1 commit


05 Jul, 2009

6 commits


08 Jun, 2009

1 commit

  • UBIFS uses timers for write-buffer write-back. It is not
    crucial for us to write-back exactly on time. We are fine
    to write-back a little earlier or later. And this means
    we may optimize UBIFS timer so that it could be groped
    with a close timer event, so that the CPU would not be
    waken up just to do the write back. This is optimization
    to lessen power consumption, which is important in
    embedded devices UBIFS is used for.

    hrtimers have a nice feature: they are effectively range
    timers, and we may defind the soft and hard limits for
    it. Standard timers do not have these feature. They may
    only be made deferrable, but this means there is effectively
    no hard limit. So, we will better use hrtimers.

    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

27 Jan, 2009

1 commit

  • When data CRC checking is disabled, UBIFS returns incorrect return
    code from the 'try_read_node()' function (0 instead of 1, which means
    CRC error), which make the caller re-read the data node again, but using
    a different code patch, so the second read is fine. Thus, we read the
    same node twice. And the result of this is that UBIFS is slower
    with no_chk_data_crc option than it is with chk_data_crc option.
    This patches fixes the problem.

    Reported-by: Reuben Dowle
    Signed-off-by: Artem Bityutskiy

    Artem Bityutskiy
     

30 Sep, 2008

2 commits


13 Aug, 2008

1 commit

  • We use ubifs_ro_mode() quite a lot, and not in fast-path, so
    there is no reason to blow the code up by having it inlined.
    Also, we usually want R/O mode change to be seen to other
    CPUs as soon as possible, so when we make this a function
    call, we will automatically have a memory barrier.

    Signed-off-by: Adrian Hunter
    Signed-off-by: Artem Bityutskiy

    Adrian Hunter
     

15 Jul, 2008

1 commit