Eric Lee / smarc-fsl-linux-kernel

21 Jul, 2011

1 commit

  • 02c24a821   fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers ... Browse Code »

    Btrfs needs to be able to control how filemap_write_and_wait_range() is called
    in fsync to make it less of a painful operation, so push down taking i_mutex and
    the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some
    file systems can drop taking the i_mutex altogether it seems, like ext3 and
    ocfs2. For correctness sake I just pushed everything down in all cases to make
    sure that we keep the current behavior the same for everybody, and then each
    individual fs maintainer can make up their mind about what to do from there.
    Thanks,

    Acked-by: Jan Kara
    Signed-off-by: Josef Bacik
    Signed-off-by: Al Viro

    Josef Bacik
     

28 May, 2010

2 commits

  • 7ea808591   drop unused dentry argument to ->fsync ... Browse Code »

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     
  • ca572727d   fs/: do not fallback to default_llseek() when readdir() uses BKL ... Browse Code »

    Do not use the fallback default_llseek() if the readdir operation of the
    filesystem still uses the big kernel lock.

    Since llseek() modifies
    file->f_pos of the directory directly it may need locking to not confuse
    readdir which usually uses file->f_pos directly as well

    Since the special characteristics of the BKL (unlocked on schedule) are
    not necessary in this case, the inode mutex can be used for locking as
    provided by generic_file_llseek(). This is only possible since all
    filesystems, except reiserfs, either use a directory as a flat file or
    with disk address offsets. Reiserfs on the other hand uses a 32bit hash
    off the filename as the offset so generic_file_llseek() can get used as
    well since the hash is always smaller than sb->s_maxbytes (= (512 << 32) -
    blocksize).

    Signed-off-by: Jan Blunck
    Acked-by: Jan Kara
    Acked-by: Anders Larsen
    Cc: Frederic Weisbecker
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    jan Blunck
     

25 Apr, 2010

1 commit

  • cac36f707   reiserfs: fix permissions on .reiserfs_priv ... Browse Code »

    Commit 677c9b2e393a0cd203bd54e9c18b012b2c73305a ("reiserfs: remove
    privroot hiding in lookup") removed the magic from the lookup code to hide
    the .reiserfs_priv directory since it was getting loaded at mount-time
    instead. The intent was that the entry would be hidden from the user via
    a poisoned d_compare, but this was faulty.

    This introduced a security issue where unprivileged users could access and
    modify extended attributes or ACLs belonging to other users, including
    root.

    This patch resolves the issue by properly hiding .reiserfs_priv. This was
    the intent of the xattr poisoning code, but it appears to have never
    worked as expected. This is fixed by using d_revalidate instead of
    d_compare.

    This patch makes -oexpose_privroot a no-op. I'm fine leaving it this way.
    The effort involved in working out the corner cases wrt permissions and
    caching outweigh the benefit of the feature.

    Signed-off-by: Jeff Mahoney
    Acked-by: Edward Shishkin
    Reported-by: Matt McCutchen
    Tested-by: Matt McCutchen
    Cc: Frederic Weisbecker
    Cc: Al Viro
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jeff Mahoney
     

30 Mar, 2010

1 commit

  • 5a0e3ad6a   include cleanup: Update gfp.h and slab.h includes to prepare for breaking implic… ... Browse Code »

    …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 Oct, 2009

1 commit

14 Sep, 2009

1 commit

  • 8ebc42323   reiserfs: kill-the-BKL ... Browse Code »

    This patch is an attempt to remove the Bkl based locking scheme from
    reiserfs and is intended.

    It is a bit inspired from an old attempt by Peter Zijlstra:

    http://lkml.indiana.edu/hypermail/linux/kernel/0704.2/2174.html

    The bkl is heavily used in this filesystem to prevent from
    concurrent write accesses on the filesystem.

    Reiserfs makes a deep use of the specific properties of the Bkl:

    - It can be acqquired recursively by a same task
    - It is released on the schedule() calls and reacquired when schedule() returns

    The two properties above are a roadmap for the reiserfs write locking so it's
    very hard to simply replace it with a common mutex.

    - We need a recursive-able locking unless we want to restructure several blocks
    of the code.
    - We need to identify the sites where the bkl was implictly relaxed
    (schedule, wait, sync, etc...) so that we can in turn release and
    reacquire our new lock explicitly.
    Such implicit releases of the lock are often required to let other
    resources producer/consumer do their job or we can suffer unexpected
    starvations or deadlocks.

    So the new lock that replaces the bkl here is a per superblock mutex with a
    specific property: it can be acquired recursively by a same task, like the
    bkl.

    For such purpose, we integrate a lock owner and a lock depth field on the
    superblock information structure.

    The first axis on this patch is to turn reiserfs_write_(un)lock() function
    into a wrapper to manage this mutex. Also some explicit calls to
    lock_kernel() have been converted to reiserfs_write_lock() helpers.

    The second axis is to find the important blocking sites (schedule...(),
    wait_on_buffer(), sync_dirty_buffer(), etc...) and then apply an explicit
    release of the write lock on these locations before blocking. Then we can
    safely wait for those who can give us resources or those who need some.
    Typically this is a fight between the current writer, the reiserfs workqueue
    (aka the async commiter) and the pdflush threads.

    The third axis is a consequence of the second. The write lock is usually
    on top of a lock dependency chain which can include the journal lock, the
    flush lock or the commit lock. So it's dangerous to release and trying to
    reacquire the write lock while we still hold other locks.

    This is fine with the bkl:

    T1 T2

    lock_kernel()
    mutex_lock(A)
    unlock_kernel()
    // do something
    lock_kernel()
    mutex_lock(A) -> already locked by T1
    schedule() (and then unlock_kernel())
    lock_kernel()
    mutex_unlock(A)
    ....

    This is not fine with a mutex:

    T1 T2

    mutex_lock(write)
    mutex_lock(A)
    mutex_unlock(write)
    // do something
    mutex_lock(write)
    mutex_lock(A) -> already locked by T1
    schedule()

    mutex_lock(write) -> already locked by T2
    deadlock

    The solution in this patch is to provide a helper which releases the write
    lock and sleep a bit if we can't lock a mutex that depend on it. It's another
    simulation of the bkl behaviour.

    The last axis is to locate the fs callbacks that are called with the bkl held,
    according to Documentation/filesystem/Locking.

    Those are:

    - reiserfs_remount
    - reiserfs_fill_super
    - reiserfs_put_super

    Reiserfs didn't need to explicitly lock because of the context of these callbacks.
    But now we must take care of that with the new locking.

    After this patch, reiserfs suffers from a slight performance regression (for now).
    On UP, a high volume write with dd reports an average of 27 MB/s instead
    of 30 MB/s without the patch applied.

    Signed-off-by: Frederic Weisbecker
    Reviewed-by: Ingo Molnar
    Cc: Jeff Mahoney
    Cc: Peter Zijlstra
    Cc: Bron Gondwana
    Cc: Andrew Morton
    Cc: Linus Torvalds
    Cc: Alexander Viro
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Frederic Weisbecker
     

12 Jun, 2009

1 commit

09 May, 2009

1 commit

  • 677c9b2e3   reiserfs: remove privroot hiding in lookup ... Browse Code »

    With Al Viro's patch to move privroot lookup to fs mount, there's no need
    to have special code to hide the privroot in reiserfs_lookup.

    I've also cleaned up the privroot hiding in reiserfs_readdir_dentry and
    removed the last user of reiserfs_xattrs().

    Signed-off-by: Jeff Mahoney
    Signed-off-by: Al Viro

    Jeff Mahoney
     

31 Mar, 2009

1 commit

  • a41f1a471   reiserfs: use generic readdir for operations across all xattrs ... Browse Code »

    The current reiserfs xattr implementation open codes reiserfs_readdir
    and frees the path before calling the filldir function. Typically, the
    filldir function is something that modifies the file system, such as a
    chown or an inode deletion that also require reading of an inode
    associated with each direntry. Since the file system is modified, the
    path retained becomes invalid for the next run. In addition, it runs
    backwards in attempt to minimize activity.

    This is clearly suboptimal from a code cleanliness perspective as well
    as performance-wise.

    This patch implements a generic reiserfs_for_each_xattr that uses the
    generic readdir and a specific filldir routine that simply populates an
    array of dentries and then performs a specific operation on them. When
    all files have been operated on, it then calls the operation on the
    directory itself.

    The result is a noticable code reduction and better performance.

    Signed-off-by: Jeff Mahoney
    Signed-off-by: Linus Torvalds

    Jeff Mahoney
     

17 Oct, 2007

1 commit

  • 80eb68d23   reiserfs: fix kernel panic on corrupted directory ... Browse Code »

    When reading corrupted reiserfs directory data, d_reclen could be a
    negative number or a big positive number, this can lead to kernel panic or
    oop. The following patch adds a sanity check.

    Signed-off-by: Lepton Wu
    Cc: Chris Mason
    Cc: Jeff Mahoney
    Cc: "Vladimir V. Saveliev"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Lepton Wu
     

24 May, 2007

1 commit

09 May, 2007

1 commit

09 Dec, 2006

1 commit

01 Oct, 2006

1 commit

01 Jul, 2006

1 commit

29 Mar, 2006

1 commit

  • 4b6f5d20b   [PATCH] Make most file operations structs in fs/ const ... Browse Code »

    This is a conversion to make the various file_operations structs in fs/
    const. Basically a regexp job, with a few manual fixups

    The goal is both to increase correctness (harder to accidentally write to
    shared datastructures) and reducing the false sharing of cachelines with
    things that get dirty in .data (while .rodata is nicely read only and thus
    cache clean)

    Signed-off-by: Arjan van de Ven
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Arjan van de Ven
     

02 Feb, 2006

1 commit

13 Jul, 2005

1 commit

  • bd4c625c0   reiserfs: run scripts/Lindent on reiserfs code ... Browse Code »

    This was a pure indentation change, using:

    scripts/Lindent fs/reiserfs/*.c include/linux/reiserfs_*.h

    to make reiserfs match the regular Linux indentation style. As Jeff
    Mahoney writes:

    The ReiserFS code is a mix of a number of different coding styles, sometimes
    different even from line-to-line. Since the code has been relatively stable
    for quite some time and there are few outstanding patches to be applied, it
    is time to reformat the code to conform to the Linux style standard outlined
    in Documentation/CodingStyle.

    This patch contains the result of running scripts/Lindent against
    fs/reiserfs/*.c and include/linux/reiserfs_*.h. There are places where the
    code can be made to look better, but I'd rather keep those patches separate
    so that there isn't a subtle by-hand hand accident in the middle of a huge
    patch. To be clear: This patch is reformatting *only*.

    A number of patches may follow that continue to make the code more consistent
    with the Linux coding style.

    Hans wasn't particularly enthusiastic about these patches, but said he
    wouldn't really oppose them either.

    Signed-off-by: Linus Torvalds

    Linus Torvalds
     

01 May, 2005

1 commit

17 Apr, 2005

1 commit

  • 1da177e4c   Linux-2.6.12-rc2 ... Browse Code »

    Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds