Eric Lee / smarc-fsl-linux-kernel

01 Jun, 2013

1 commit

  • 5d477b607   vfs: Fix invalid ida_remove() call ... Browse Code »

    When the group id of a shared mount is not allocated, the umount still
    tries to call mnt_release_group_id(), which eventually hits a kernel
    warning at ida_remove() spewing a message like:
    ida_remove called for id=0 which is not allocated.

    This patch fixes the bug simply checking the group id in the caller.

    Reported-by: Cristian Rodríguez
    Signed-off-by: Takashi Iwai
    Signed-off-by: Al Viro

    Takashi Iwai
     

02 May, 2013

1 commit

  • 20b4fb485   Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs ... Browse Code »

    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
     

10 Apr, 2013

2 commits

27 Mar, 2013

1 commit

  • 132c94e31   vfs: Carefully propogate mounts across user namespaces ... Browse Code »

    As a matter of policy MNT_READONLY should not be changable if the
    original mounter had more privileges than creator of the mount
    namespace.

    Add the flag CL_UNPRIVILEGED to note when we are copying a mount from
    a mount namespace that requires more privileges to a mount namespace
    that requires fewer privileges.

    When the CL_UNPRIVILEGED flag is set cause clone_mnt to set MNT_NO_REMOUNT
    if any of the mnt flags that should never be changed are set.

    This protects both mount propagation and the initial creation of a less
    privileged mount namespace.

    Cc: stable@vger.kernel.org
    Acked-by: Serge Hallyn
    Reported-by: Andy Lutomirski
    Signed-off-by: "Eric W. Biederman"

    Eric W. Biederman
     

14 Jul, 2012

1 commit

  • be34d1a3b   VFS: Make clone_mnt()/copy_tree()/collect_mounts() return errors ... Browse Code »

    copy_tree() can theoretically fail in a case other than ENOMEM, but always
    returns NULL which is interpreted by callers as -ENOMEM. Change it to return
    an explicit error.

    Also change clone_mnt() for consistency and because union mounts will add new
    error cases.

    Thanks to Andreas Gruenbacher for a bug fix.
    [AV: folded braino fix by Dan Carpenter]

    Original-author: Valerie Aurora
    Signed-off-by: David Howells
    Cc: Valerie Aurora
    Cc: Andreas Gruenbacher
    Signed-off-by: Al Viro

    David Howells
     

30 May, 2012

1 commit

  • 962830df3   brlocks/lglocks: API cleanups ... Browse Code »

    lglocks and brlocks are currently generated with some complicated macros
    in lglock.h. But there's no reason to not just use common utility
    functions and put all the data into a common data structure.

    In preparation, this patch changes the API to look more like normal
    function calls with pointers, not magic macros.

    The patch is rather large because I move over all users in one go to keep
    it bisectable. This impacts the VFS somewhat in terms of lines changed.
    But no actual behaviour change.

    [akpm@linux-foundation.org: checkpatch fixes]
    Signed-off-by: Andi Kleen
    Cc: Al Viro
    Cc: Rusty Russell
    Signed-off-by: Andrew Morton
    Signed-off-by: Rusty Russell
    Signed-off-by: Al Viro

    Andi Kleen
     

04 Jan, 2012

29 commits

07 Jan, 2011

1 commit

  • b3e19d924   fs: scale mntget/mntput ... Browse Code »

    The problem that this patch aims to fix is vfsmount refcounting scalability.
    We need to take a reference on the vfsmount for every successful path lookup,
    which often go to the same mount point.

    The fundamental difficulty is that a "simple" reference count can never be made
    scalable, because any time a reference is dropped, we must check whether that
    was the last reference. To do that requires communication with all other CPUs
    that may have taken a reference count.

    We can make refcounts more scalable in a couple of ways, involving keeping
    distributed counters, and checking for the global-zero condition less
    frequently.

    - check the global sum once every interval (this will delay zero detection
    for some interval, so it's probably a showstopper for vfsmounts).

    - keep a local count and only taking the global sum when local reaches 0 (this
    is difficult for vfsmounts, because we can't hold preempt off for the life of
    a reference, so a counter would need to be per-thread or tied strongly to a
    particular CPU which requires more locking).

    - keep a local difference of increments and decrements, which allows us to sum
    the total difference and hence find the refcount when summing all CPUs. Then,
    keep a single integer "long" refcount for slow and long lasting references,
    and only take the global sum of local counters when the long refcount is 0.

    This last scheme is what I implemented here. Attached mounts and process root
    and working directory references are "long" references, and everything else is
    a short reference.

    This allows scalable vfsmount references during path walking over mounted
    subtrees and unattached (lazy umounted) mounts with processes still running
    in them.

    This results in one fewer atomic op in the fastpath: mntget is now just a
    per-CPU inc, rather than an atomic inc; and mntput just requires a spinlock
    and non-atomic decrement in the common case. However code is otherwise bigger
    and heavier, so single threaded performance is basically a wash.

    Signed-off-by: Nick Piggin

    Nick Piggin
     

18 Aug, 2010

1 commit

  • 99b7db7b8   fs: brlock vfsmount_lock ... Browse Code »

    fs: brlock vfsmount_lock

    Use a brlock for the vfsmount lock. It must be taken for write whenever
    modifying the mount hash or associated fields, and may be taken for read when
    performing mount hash lookups.

    A new lock is added for the mnt-id allocator, so it doesn't need to take
    the heavy vfsmount write-lock.

    The number of atomics should remain the same for fastpath rlock cases, though
    code would be slightly slower due to per-cpu access. Scalability is not not be
    much improved in common cases yet, due to other locks (ie. dcache_lock) getting
    in the way. However path lookups crossing mountpoints should be one case where
    scalability is improved (currently requiring the global lock).

    The slowpath is slower due to use of brlock. On a 64 core, 64 socket, 32 node
    Altix system (high latency to remote nodes), a simple umount microbenchmark
    (mount --bind mnt mnt2 ; umount mnt2 loop 1000 times), before this patch it
    took 6.8s, afterwards took 7.1s, about 5% slower.

    Cc: Al Viro
    Signed-off-by: Nick Piggin
    Signed-off-by: Al Viro

    Nick Piggin
     

04 Mar, 2010

1 commit

  • 796a6b521   Kill CL_PROPAGATION, sanitize fs/pnode.c:get_source() ... Browse Code »

    First of all, get_source() never results in CL_PROPAGATION
    alone. We either get CL_MAKE_SHARED (for the continuation
    of peer group) or CL_SLAVE (slave that is not shared) or both
    (beginning of peer group among slaves). Massage the code to
    make that explicit, kill CL_PROPAGATION test in clone_mnt()
    (nothing sets CL_MAKE_SHARED without CL_PROPAGATION and in
    clone_mnt() we are checking CL_PROPAGATION after we'd found
    that there's no CL_SLAVE, so the check for CL_MAKE_SHARED
    would do just as well).

    Fix comments, while we are at it...

    Signed-off-by: Al Viro

    Al Viro
     

23 Apr, 2008

1 commit