02 May, 2013

1 commit

  • Pull VFS updates from Al Viro,

    Misc cleanups all over the place, mainly wrt /proc interfaces (switch
    create_proc_entry to proc_create(), get rid of the deprecated
    create_proc_read_entry() in favor of using proc_create_data() and
    seq_file etc).

    7kloc removed.

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
    don't bother with deferred freeing of fdtables
    proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
    proc: Make the PROC_I() and PDE() macros internal to procfs
    proc: Supply a function to remove a proc entry by PDE
    take cgroup_open() and cpuset_open() to fs/proc/base.c
    ppc: Clean up scanlog
    ppc: Clean up rtas_flash driver somewhat
    hostap: proc: Use remove_proc_subtree()
    drm: proc: Use remove_proc_subtree()
    drm: proc: Use minor->index to label things, not PDE->name
    drm: Constify drm_proc_list[]
    zoran: Don't print proc_dir_entry data in debug
    reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
    proc: Supply an accessor for getting the data from a PDE's parent
    airo: Use remove_proc_subtree()
    rtl8192u: Don't need to save device proc dir PDE
    rtl8187se: Use a dir under /proc/net/r8180/
    proc: Add proc_mkdir_data()
    proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
    proc: Move PDE_NET() to fs/proc/proc_net.c
    ...

    Linus Torvalds
     

01 May, 2013

2 commits

  • threadgroup_lock() takes signal->cred_guard_mutex to ensure that
    thread_group_leader() is stable. This doesn't look nice, the scope of
    this lock in do_execve() is huge.

    And as Dave pointed out this can lead to deadlock, we have the
    following dependencies:

    do_execve: cred_guard_mutex -> i_mutex
    cgroup_mount: i_mutex -> cgroup_mutex
    attach_task_by_pid: cgroup_mutex -> cred_guard_mutex

    Change de_thread() to take threadgroup_change_begin() around the
    switch-the-leader code and change threadgroup_lock() to avoid
    ->cred_guard_mutex.

    Note that de_thread() can't sleep with ->group_rwsem held, this can
    obviously deadlock with the exiting leader if the writer is active, so it
    does threadgroup_change_end() before schedule().

    Reported-by: Dave Jones
    Acked-by: Tejun Heo
    Acked-by: Li Zefan
    Signed-off-by: Oleg Nesterov
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • set_task_comm() does memset() + wmb() before strlcpy(). This buys
    nothing and to add to the confusion, the comment is wrong.

    - We do not need memset() to be "safe from non-terminating string
    reads", the final char is always zero and we never change it.

    - wmb() is paired with nothing, it cannot prevent from printing
    the mixture of the old/new data unless the reader takes the lock.

    Signed-off-by: Oleg Nesterov
    Cc: Andi Kleen
    Cc: John Stultz
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     

30 Apr, 2013

2 commits

  • On architectures where a pgd entry may be shared between user and kernel
    (e.g. ARM+LPAE), freeing page tables needs a ceiling other than 0.
    This patch introduces a generic USER_PGTABLES_CEILING that arch code can
    override. It is the responsibility of the arch code setting the ceiling
    to ensure the complete freeing of the page tables (usually in
    pgd_free()).

    [catalin.marinas@arm.com: commit log; shift_arg_pages(), asm-generic/pgtables.h changes]
    Signed-off-by: Hugh Dickins
    Signed-off-by: Catalin Marinas
    Cc: Russell King
    Cc: [3.3+]
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Hugh Dickins
     
  • switch binfmts that use ->read() to that (and to kernel_read()
    in several cases in binfmt_flat - sure, it's nommu, but still,
    doing ->read() into kmalloc'ed buffer...)

    Signed-off-by: Al Viro

    Al Viro
     

28 Feb, 2013

1 commit

  • The existing SUID_DUMP_* defines duplicate the newer SUID_DUMPABLE_*
    defines introduced in 54b501992dd2 ("coredump: warn about unsafe
    suid_dumpable / core_pattern combo"). Remove the new ones, and use the
    prior values instead.

    Signed-off-by: Kees Cook
    Reported-by: Chen Gang
    Cc: Alexander Viro
    Cc: Alan Cox
    Cc: "Eric W. Biederman"
    Cc: Doug Ledford
    Cc: Serge Hallyn
    Cc: James Morris
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kees Cook
     

26 Feb, 2013

1 commit


23 Feb, 2013

1 commit


12 Jan, 2013

1 commit

  • The tricky problem is this check:

    if (i++ >= max)

    icc (mis)optimizes this check as:

    if (++i > max)

    The check now becomes a no-op since max is MAX_ARG_STRINGS (0x7FFFFFFF).

    This is "allowed" by the C standard, assuming i++ never overflows,
    because signed integer overflow is undefined behavior. This
    optimization effectively reverts the previous commit 362e6663ef23
    ("exec.c, compat.c: fix count(), compat_count() bounds checking") that
    tries to fix the check.

    This patch simply moves ++ after the check.

    Signed-off-by: Xi Wang
    Cc: Jason Baron
    Cc: Al Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Xi Wang
     

21 Dec, 2012

3 commits

  • Merge the rest of Andrew's patches for -rc1:
    "A bunch of fixes and misc missed-out-on things.

    That'll do for -rc1. I still have a batch of IPC patches which still
    have a possible bug report which I'm chasing down."

    * emailed patches from Andrew Morton : (25 commits)
    keys: use keyring_alloc() to create module signing keyring
    keys: fix unreachable code
    sendfile: allows bypassing of notifier events
    SGI-XP: handle non-fatal traps
    fat: fix incorrect function comment
    Documentation: ABI: remove testing/sysfs-devices-node
    proc: fix inconsistent lock state
    linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors
    memcg: don't register hotcpu notifier from ->css_alloc()
    checkpatch: warn on uapi #includes that #include
    mm: cma: WARN if freed memory is still in use
    exec: do not leave bprm->interp on stack
    ...

    Linus Torvalds
     
  • Pull signal handling cleanups from Al Viro:
    "sigaltstack infrastructure + conversion for x86, alpha and um,
    COMPAT_SYSCALL_DEFINE infrastructure.

    Note that there are several conflicts between "unify
    SS_ONSTACK/SS_DISABLE definitions" and UAPI patches in mainline;
    resolution is trivial - just remove definitions of SS_ONSTACK and
    SS_DISABLED from arch/*/uapi/asm/signal.h; they are all identical and
    include/uapi/linux/signal.h contains the unified variant."

    Fixed up conflicts as per Al.

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
    alpha: switch to generic sigaltstack
    new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those
    generic compat_sys_sigaltstack()
    introduce generic sys_sigaltstack(), switch x86 and um to it
    new helper: compat_user_stack_pointer()
    new helper: restore_altstack()
    unify SS_ONSTACK/SS_DISABLE definitions
    new helper: current_user_stack_pointer()
    missing user_stack_pointer() instances
    Bury the conditionals from kernel_thread/kernel_execve series
    COMPAT_SYSCALL_DEFINE: infrastructure

    Linus Torvalds
     
  • If a series of scripts are executed, each triggering module loading via
    unprintable bytes in the script header, kernel stack contents can leak
    into the command line.

    Normally execution of binfmt_script and binfmt_misc happens recursively.
    However, when modules are enabled, and unprintable bytes exist in the
    bprm->buf, execution will restart after attempting to load matching
    binfmt modules. Unfortunately, the logic in binfmt_script and
    binfmt_misc does not expect to get restarted. They leave bprm->interp
    pointing to their local stack. This means on restart bprm->interp is
    left pointing into unused stack memory which can then be copied into the
    userspace argv areas.

    After additional study, it seems that both recursion and restart remains
    the desirable way to handle exec with scripts, misc, and modules. As
    such, we need to protect the changes to interp.

    This changes the logic to require allocation for any changes to the
    bprm->interp. To avoid adding a new kmalloc to every exec, the default
    value is left as-is. Only when passing through binfmt_script or
    binfmt_misc does an allocation take place.

    For a proof of concept, see DoTest.sh from:

    http://www.halfdog.net/Security/2012/LinuxKernelBinfmtScriptStackDataDisclosure/

    Signed-off-by: Kees Cook
    Cc: halfdog
    Cc: P J P
    Cc: Alexander Viro
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kees Cook
     

20 Dec, 2012

1 commit

  • All architectures have
    CONFIG_GENERIC_KERNEL_THREAD
    CONFIG_GENERIC_KERNEL_EXECVE
    __ARCH_WANT_SYS_EXECVE
    None of them have __ARCH_WANT_KERNEL_EXECVE and there are only two callers
    of kernel_execve() (which is a trivial wrapper for do_execve() now) left.
    Kill the conditionals and make both callers use do_execve().

    Signed-off-by: Al Viro

    Al Viro
     

18 Dec, 2012

3 commits

  • Merge misc patches from Andrew Morton:
    "Incoming:

    - lots of misc stuff

    - backlight tree updates

    - lib/ updates

    - Oleg's percpu-rwsem changes

    - checkpatch

    - rtc

    - aoe

    - more checkpoint/restart support

    I still have a pile of MM stuff pending - Pekka should be merging
    later today after which that is good to go. A number of other things
    are twiddling thumbs awaiting maintainer merges."

    * emailed patches from Andrew Morton : (180 commits)
    scatterlist: don't BUG when we can trivially return a proper error.
    docs: update documentation about /proc//fdinfo/ fanotify output
    fs, fanotify: add @mflags field to fanotify output
    docs: add documentation about /proc//fdinfo/ output
    fs, notify: add procfs fdinfo helper
    fs, exportfs: add exportfs_encode_inode_fh() helper
    fs, exportfs: escape nil dereference if no s_export_op present
    fs, epoll: add procfs fdinfo helper
    fs, eventfd: add procfs fdinfo helper
    procfs: add ability to plug in auxiliary fdinfo providers
    tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test
    breakpoint selftests: print failure status instead of cause make error
    kcmp selftests: print fail status instead of cause make error
    kcmp selftests: make run_tests fix
    mem-hotplug selftests: print failure status instead of cause make error
    cpu-hotplug selftests: print failure status instead of cause make error
    mqueue selftests: print failure status instead of cause make error
    vm selftests: print failure status instead of cause make error
    ubifs: use prandom_bytes
    mtd: nandsim: use prandom_bytes
    ...

    Linus Torvalds
     
  • To avoid an explosion of request_module calls on a chain of abusive
    scripts, fail maximum recursion with -ELOOP instead of -ENOEXEC. As soon
    as maximum recursion depth is hit, the error will fail all the way back
    up the chain, aborting immediately.

    This also has the side-effect of stopping the user's shell from attempting
    to reexecute the top-level file as a shell script. As seen in the
    dash source:

    if (cmd != path_bshell && errno == ENOEXEC) {
    *argv-- = cmd;
    *argv = cmd = path_bshell;
    goto repeat;
    }

    The above logic was designed for running scripts automatically that lacked
    the "#!" header, not to re-try failed recursion. On a legitimate -ENOEXEC,
    things continue to behave as the shell expects.

    Additionally, when tracking recursion, the binfmt handlers should not be
    involved. The recursion being tracked is the depth of calls through
    search_binary_handler(), so that function should be exclusively responsible
    for tracking the depth.

    Signed-off-by: Kees Cook
    Cc: halfdog
    Cc: P J P
    Cc: Alexander Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kees Cook
     
  • Pull user namespace changes from Eric Biederman:
    "While small this set of changes is very significant with respect to
    containers in general and user namespaces in particular. The user
    space interface is now complete.

    This set of changes adds support for unprivileged users to create user
    namespaces and as a user namespace root to create other namespaces.
    The tyranny of supporting suid root preventing unprivileged users from
    using cool new kernel features is broken.

    This set of changes completes the work on setns, adding support for
    the pid, user, mount namespaces.

    This set of changes includes a bunch of basic pid namespace
    cleanups/simplifications. Of particular significance is the rework of
    the pid namespace cleanup so it no longer requires sending out
    tendrils into all kinds of unexpected cleanup paths for operation. At
    least one case of broken error handling is fixed by this cleanup.

    The files under /proc//ns/ have been converted from regular files
    to magic symlinks which prevents incorrect caching by the VFS,
    ensuring the files always refer to the namespace the process is
    currently using and ensuring that the ptrace_mayaccess permission
    checks are always applied.

    The files under /proc//ns/ have been given stable inode numbers
    so it is now possible to see if different processes share the same
    namespaces.

    Through the David Miller's net tree are changes to relax many of the
    permission checks in the networking stack to allowing the user
    namespace root to usefully use the networking stack. Similar changes
    for the mount namespace and the pid namespace are coming through my
    tree.

    Two small changes to add user namespace support were commited here adn
    in David Miller's -net tree so that I could complete the work on the
    /proc//ns/ files in this tree.

    Work remains to make it safe to build user namespaces and 9p, afs,
    ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the
    Kconfig guard remains in place preventing that user namespaces from
    being built when any of those filesystems are enabled.

    Future design work remains to allow root users outside of the initial
    user namespace to mount more than just /proc and /sys."

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits)
    proc: Usable inode numbers for the namespace file descriptors.
    proc: Fix the namespace inode permission checks.
    proc: Generalize proc inode allocation
    userns: Allow unprivilged mounts of proc and sysfs
    userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file
    procfs: Print task uids and gids in the userns that opened the proc file
    userns: Implement unshare of the user namespace
    userns: Implent proc namespace operations
    userns: Kill task_user_ns
    userns: Make create_new_namespaces take a user_ns parameter
    userns: Allow unprivileged use of setns.
    userns: Allow unprivileged users to create new namespaces
    userns: Allow setting a userns mapping to your current uid.
    userns: Allow chown and setgid preservation
    userns: Allow unprivileged users to create user namespaces.
    userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped
    userns: fix return value on mntns_install() failure
    vfs: Allow unprivileged manipulation of the mount namespace.
    vfs: Only support slave subtrees across different user namespaces
    vfs: Add a user namespace reference from struct mnt_namespace
    ...

    Linus Torvalds
     

29 Nov, 2012

5 commits


19 Nov, 2012

1 commit

  • When performing an exec where the binary lives in one user namespace and
    the execing process lives in another usre namespace there is the possibility
    that the target uids can not be represented.

    Instead of failing the exec simply ignore the suid/sgid bits and run
    the binary with lower privileges. We already do this in the case
    of MNT_NOSUID so this should be a well tested code path.

    As the user and group are not changed this should not introduce any
    security issues.

    Acked-by: Serge Hallyn
    Signed-off-by: Eric W. Biederman

    Eric W. Biederman
     

26 Oct, 2012

1 commit


13 Oct, 2012

2 commits

  • ...and fix up the callers. For do_file_open_root, just declare a
    struct filename on the stack and fill out the .name field. For
    do_filp_open, make it also take a struct filename pointer, and fix up its
    callers to call it appropriately.

    For filp_open, add a variant that takes a struct filename pointer and turn
    filp_open into a wrapper around it.

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

    Jeff Layton
     
  • getname() is intended to copy pathname strings from userspace into a
    kernel buffer. The result is just a string in kernel space. It would
    however be quite helpful to be able to attach some ancillary info to
    the string.

    For instance, we could attach some audit-related info to reduce the
    amount of audit-related processing needed. When auditing is enabled,
    we could also call getname() on the string more than once and not
    need to recopy it from userspace.

    This patchset converts the getname()/putname() interfaces to return
    a struct instead of a string. For now, the struct just tracks the
    string in kernel space and the original userland pointer for it.

    Later, we'll add other information to the struct as it becomes
    convenient.

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

    Jeff Layton
     

10 Oct, 2012

1 commit

  • Pull generic execve() changes from Al Viro:
    "This introduces the generic kernel_thread() and kernel_execve()
    functions, and switches x86, arm, alpha, um and s390 over to them."

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
    s390: convert to generic kernel_execve()
    s390: switch to generic kernel_thread()
    s390: fold kernel_thread_helper() into ret_from_fork()
    s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
    um: switch to generic kernel_thread()
    x86, um/x86: switch to generic sys_execve and kernel_execve
    x86: split ret_from_fork
    alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
    alpha: switch to generic kernel_thread()
    alpha: switch to generic sys_execve()
    arm: get rid of execve wrapper, switch to generic execve() implementation
    arm: optimized current_pt_regs()
    arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
    arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
    generic sys_execve()
    generic kernel_execve()
    new helper: current_pt_regs()
    preparation for generic kernel_thread()
    um: kill thread->forking
    um: let signal_delivered() do SIGTRAP on singlestepping into handler
    ...

    Linus Torvalds
     

09 Oct, 2012

2 commits

  • During mremap(), the destination VMA is generally placed after the
    original vma in rmap traversal order: in move_vma(), we always have
    new_pgoff >= vma->vm_pgoff, and as a result new_vma->vm_pgoff >=
    vma->vm_pgoff unless vma_merge() merged the new vma with an adjacent one.

    When the destination VMA is placed after the original in rmap traversal
    order, we can avoid taking the rmap locks in move_ptes().

    Essentially, this reintroduces the optimization that had been disabled in
    "mm anon rmap: remove anon_vma_moveto_tail". The difference is that we
    don't try to impose the rmap traversal order; instead we just rely on
    things being in the desired order in the common case and fall back to
    taking locks in the uncommon case. Also we skip the i_mmap_mutex in
    addition to the anon_vma lock: in both cases, the vmas are traversed in
    increasing vm_pgoff order with ties resolved in tree insertion order.

    Signed-off-by: Michel Lespinasse
    Cc: Andrea Arcangeli
    Cc: Rik van Riel
    Cc: Peter Zijlstra
    Cc: Daniel Santos
    Cc: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michel Lespinasse
     
  • Change de_thread() to use KILLABLE rather than UNINTERRUPTIBLE while
    waiting for other threads. The only complication is that we should
    clear ->group_exit_task and ->notify_count before we return, and we
    should do this under tasklist_lock. -EAGAIN is used to match the
    initial signal_group_exit() check/return, it doesn't really matter.

    This fixes the (unlikely) race with coredump. de_thread() checks
    signal_group_exit() before it starts to kill the subthreads, but this
    can't help if another CLONE_VM (but non CLONE_THREAD) task starts the
    coredumping after de_thread() unlocks ->siglock. In this case the
    killed sub-thread can block in exit_mm() waiting for coredump_finish(),
    execing thread waits for that sub-thead, and the coredumping thread
    waits for execing thread. Deadlock.

    Signed-off-by: Oleg Nesterov
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     

06 Oct, 2012

2 commits

  • Cosmetic. Change setup_new_exec() and task_dumpable() to use
    SUID_DUMPABLE_ENABLED for /bin/grep.

    [akpm@linux-foundation.org: checkpatch fixes]
    Signed-off-by: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • Create a new header file, fs/coredump.h, which contains functions only
    used by the new coredump.c. It also moves do_coredump to the
    include/linux/coredump.h header file, for consistency.

    Signed-off-by: Alex Kelly
    Reviewed-by: Josh Triplett
    Acked-by: Serge Hallyn
    Acked-by: Kees Cook
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alex Kelly
     

03 Oct, 2012

1 commit

  • This prepares for making core dump functionality optional.

    The variable "suid_dumpable" and associated functions are left in fs/exec.c
    because they're used elsewhere, such as in ptrace.

    Signed-off-by: Alex Kelly
    Reviewed-by: Josh Triplett
    Acked-by: Serge Hallyn
    Acked-by: Kees Cook
    Signed-off-by: Andrew Morton
    Signed-off-by: Al Viro

    Alex Kelly
     

01 Oct, 2012

2 commits

  • Selected by __ARCH_WANT_SYS_EXECVE in unistd.h. Requires
    * working current_pt_regs()
    * *NOT* doing a syscall-in-kernel kind of kernel_execve()
    implementation. Using generic kernel_execve() is fine.

    Signed-off-by: Al Viro

    Al Viro
     
  • based mostly on arm and alpha versions. Architectures can define
    __ARCH_WANT_KERNEL_EXECVE and use it, provided that
    * they have working current_pt_regs(), even for kernel threads.
    * kernel_thread-spawned threads do have space for pt_regs
    in the normal location. Normally that's as simple as switching to
    generic kernel_thread() and making sure that kernel threads do *not*
    go through return from syscall path; call the payload from equivalent
    of ret_from_fork if we are in a kernel thread (or just have separate
    ret_from_kernel_thread and make copy_thread() use it instead of
    ret_from_fork in kernel thread case).
    * they have ret_from_kernel_execve(); it is called after
    successful do_execve() done by kernel_execve() and gets normal
    pt_regs location passed to it as argument. It's essentially
    a longjmp() analog - it should set sp, etc. to the situation
    expected at the return for syscall and go there. Eventually
    the need for that sucker will disappear, but that'll take some
    surgery on kernel_thread() payloads.

    Signed-off-by: Al Viro

    Al Viro
     

27 Sep, 2012

3 commits


20 Sep, 2012

1 commit


02 Aug, 2012

1 commit

  • Pull second vfs pile from Al Viro:
    "The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the
    deadlock reproduced by xfstests 068), symlink and hardlink restriction
    patches, plus assorted cleanups and fixes.

    Note that another fsfreeze deadlock (emergency thaw one) is *not*
    dealt with - the series by Fernando conflicts a lot with Jan's, breaks
    userland ABI (FIFREEZE semantics gets changed) and trades the deadlock
    for massive vfsmount leak; this is going to be handled next cycle.
    There probably will be another pull request, but that stuff won't be
    in it."

    Fix up trivial conflicts due to unrelated changes next to each other in
    drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c}

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
    delousing target_core_file a bit
    Documentation: Correct s_umount state for freeze_fs/unfreeze_fs
    fs: Remove old freezing mechanism
    ext2: Implement freezing
    btrfs: Convert to new freezing mechanism
    nilfs2: Convert to new freezing mechanism
    ntfs: Convert to new freezing mechanism
    fuse: Convert to new freezing mechanism
    gfs2: Convert to new freezing mechanism
    ocfs2: Convert to new freezing mechanism
    xfs: Convert to new freezing code
    ext4: Convert to new freezing mechanism
    fs: Protect write paths by sb_start_write - sb_end_write
    fs: Skip atime update on frozen filesystem
    fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
    fs: Improve filesystem freezing handling
    switch the protection of percpu_counter list to spinlock
    nfsd: Push mnt_want_write() outside of i_mutex
    btrfs: Push mnt_want_write() outside of i_mutex
    fat: Push mnt_want_write() outside of i_mutex
    ...

    Linus Torvalds
     

31 Jul, 2012

2 commits