25 Oct, 2013

1 commit


01 Aug, 2013

1 commit

  • Refuse RW mount of isofs filesystem. So far we just silently changed it
    to RO mount but when the media is writeable, block layer won't notice
    this change and thus will think device is used RW and will block eject
    button of the drive. That is unexpected by users because for
    non-writeable media eject button works just fine.

    Userspace mount(8) command handles this just fine and retries mounting
    with MS_RDONLY set so userspace shouldn't see any regression. Plus any
    tool mounting isofs is likely confronted with the case of read-only
    media where block layer already refuses to mount the filesystem without
    MS_RDONLY set so our behavior shouldn't be anything new for it.

    Reported-by: Hui Wang
    Signed-off-by: Jan Kara

    Jan Kara
     

29 Jun, 2013

2 commits

  • Instances either don't look at it at all (the majority of cases) or
    only want it to find the superblock (which can be had as dentry->d_sb).
    A few cases that want more are actually safe with dentry->d_inode -
    the only precaution needed is the check that it hadn't been replaced with
    NULL by rmdir() or by overwriting rename(), which case should be simply
    treated as cache miss.

    Signed-off-by: Linus Torvalds
    Signed-off-by: Al Viro

    Linus Torvalds
     
  • Signed-off-by: Al Viro

    Al Viro
     

13 Mar, 2013

1 commit

  • I had assumed that the only use of module aliases for filesystems
    prior to "fs: Limit sys_mount to only request filesystem modules."
    was in request_module. It turns out I was wrong. At least mkinitcpio
    in Arch linux uses these aliases.

    So readd the preexising aliases, to keep from breaking userspace.

    Userspace eventually will have to follow and use the same aliases the
    kernel does. So at some point we may be delete these aliases without
    problems. However that day is not today.

    Signed-off-by: "Eric W. Biederman"

    Eric W. Biederman
     

04 Mar, 2013

1 commit

  • Modify the request_module to prefix the file system type with "fs-"
    and add aliases to all of the filesystems that can be built as modules
    to match.

    A common practice is to build all of the kernel code and leave code
    that is not commonly needed as modules, with the result that many
    users are exposed to any bug anywhere in the kernel.

    Looking for filesystems with a fs- prefix limits the pool of possible
    modules that can be loaded by mount to just filesystems trivially
    making things safer with no real cost.

    Using aliases means user space can control the policy of which
    filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
    with blacklist and alias directives. Allowing simple, safe,
    well understood work-arounds to known problematic software.

    This also addresses a rare but unfortunate problem where the filesystem
    name is not the same as it's module name and module auto-loading
    would not work. While writing this patch I saw a handful of such
    cases. The most significant being autofs that lives in the module
    autofs4.

    This is relevant to user namespaces because we can reach the request
    module in get_fs_type() without having any special permissions, and
    people get uncomfortable when a user specified string (in this case
    the filesystem type) goes all of the way to request_module.

    After having looked at this issue I don't think there is any
    particular reason to perform any filtering or permission checks beyond
    making it clear in the module request that we want a filesystem
    module. The common pattern in the kernel is to call request_module()
    without regards to the users permissions. In general all a filesystem
    module does once loaded is call register_filesystem() and go to sleep.
    Which means there is not much attack surface exposed by loading a
    filesytem module unless the filesystem is mounted. In a user
    namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
    which most filesystems do not set today.

    Acked-by: Serge Hallyn
    Acked-by: Kees Cook
    Reported-by: Kees Cook
    Signed-off-by: "Eric W. Biederman"

    Eric W. Biederman
     

26 Feb, 2013

1 commit


23 Feb, 2013

1 commit


10 Oct, 2012

1 commit

  • Fuzzing with trinity oopsed on the 1st instruction of shmem_fh_to_dentry(),
    u64 inum = fid->raw[2];
    which is unhelpfully reported as at the end of shmem_alloc_inode():

    BUG: unable to handle kernel paging request at ffff880061cd3000
    IP: [] shmem_alloc_inode+0x40/0x40
    Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
    Call Trace:
    [] ? exportfs_decode_fh+0x79/0x2d0
    [] do_handle_open+0x163/0x2c0
    [] sys_open_by_handle_at+0xc/0x10
    [] tracesys+0xe1/0xe6

    Right, tmpfs is being stupid to access fid->raw[2] before validating that
    fh_len includes it: the buffer kmalloc'ed by do_sys_name_to_handle() may
    fall at the end of a page, and the next page not be present.

    But some other filesystems (ceph, gfs2, isofs, reiserfs, xfs) are being
    careless about fh_len too, in fh_to_dentry() and/or fh_to_parent(), and
    could oops in the same way: add the missing fh_len checks to those.

    Reported-by: Sasha Levin
    Signed-off-by: Hugh Dickins
    Cc: Al Viro
    Cc: Sage Weil
    Cc: Steven Whitehouse
    Cc: Christoph Hellwig
    Cc: stable@vger.kernel.org
    Signed-off-by: Al Viro

    Hugh Dickins
     

03 Oct, 2012

2 commits

  • Pull vfs update from Al Viro:

    - big one - consolidation of descriptor-related logics; almost all of
    that is moved to fs/file.c

    (BTW, I'm seriously tempted to rename the result to fd.c. As it is,
    we have a situation when file_table.c is about handling of struct
    file and file.c is about handling of descriptor tables; the reasons
    are historical - file_table.c used to be about a static array of
    struct file we used to have way back).

    A lot of stray ends got cleaned up and converted to saner primitives,
    disgusting mess in android/binder.c is still disgusting, but at least
    doesn't poke so much in descriptor table guts anymore. A bunch of
    relatively minor races got fixed in process, plus an ext4 struct file
    leak.

    - related thing - fget_light() partially unuglified; see fdget() in
    there (and yes, it generates the code as good as we used to have).

    - also related - bits of Cyrill's procfs stuff that got entangled into
    that work; _not_ all of it, just the initial move to fs/proc/fd.c and
    switch of fdinfo to seq_file.

    - Alex's fs/coredump.c spiltoff - the same story, had been easier to
    take that commit than mess with conflicts. The rest is a separate
    pile, this was just a mechanical code movement.

    - a few misc patches all over the place. Not all for this cycle,
    there'll be more (and quite a few currently sit in akpm's tree)."

    Fix up trivial conflicts in the android binder driver, and some fairly
    simple conflicts due to two different changes to the sock_alloc_file()
    interface ("take descriptor handling from sock_alloc_file() to callers"
    vs "net: Providing protocol type via system.sockprotoname xattr of
    /proc/PID/fd entries" adding a dentry name to the socket)

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
    MAX_LFS_FILESIZE should be a loff_t
    compat: fs: Generic compat_sys_sendfile implementation
    fs: push rcu_barrier() from deactivate_locked_super() to filesystems
    btrfs: reada_extent doesn't need kref for refcount
    coredump: move core dump functionality into its own file
    coredump: prevent double-free on an error path in core dumper
    usb/gadget: fix misannotations
    fcntl: fix misannotations
    ceph: don't abuse d_delete() on failure exits
    hypfs: ->d_parent is never NULL or negative
    vfs: delete surplus inode NULL check
    switch simple cases of fget_light to fdget
    new helpers: fdget()/fdput()
    switch o2hb_region_dev_write() to fget_light()
    proc_map_files_readdir(): don't bother with grabbing files
    make get_file() return its argument
    vhost_set_vring(): turn pollstart/pollstop into bool
    switch prctl_set_mm_exe_file() to fget_light()
    switch xfs_find_handle() to fget_light()
    switch xfs_swapext() to fget_light()
    ...

    Linus Torvalds
     
  • There's no reason to call rcu_barrier() on every
    deactivate_locked_super(). We only need to make sure that all delayed rcu
    free inodes are flushed before we destroy related cache.

    Removing rcu_barrier() from deactivate_locked_super() affects some fast
    paths. E.g. on my machine exit_group() of a last process in IPC
    namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time.

    Signed-off-by: Kirill A. Shutemov
    Cc: Al Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Al Viro

    Kirill A. Shutemov
     

21 Sep, 2012

1 commit


25 Jul, 2012

1 commit

  • Pull misc udf, ext2, ext3, and isofs fixes from Jan Kara:
    "Assorted, mostly trivial, fixes for udf, ext2, ext3, and isofs. I'm
    on vacation and scarcely checking email since we are expecting baby
    any day now but these fixes should be safe to go in and I don't want
    to delay them unnecessarily."

    * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
    udf: avoid info leak on export
    isofs: avoid info leak on export
    udf: Improve table length check to avoid possible overflow
    ext3: Check return value of blkdev_issue_flush()
    jbd: Check return value of blkdev_issue_flush()
    udf: Do not decrement i_blocks when freeing indirect extent block
    udf: Fix memory leak when mounting
    ext2: cleanup the confused goto label
    UDF: Remove unnecessary variable "offset" from udf_fill_inode
    udf: stop using s_dirt
    ext3: force ro mount if ext3_setup_super() fails
    quota: fix checkpatch.pl warning by replacing with

    Linus Torvalds
     

14 Jul, 2012

1 commit

  • Just the flags; only NFS cares even about that, but there are
    legitimate uses for such argument. And getting rid of that
    completely would require splitting ->lookup() into a couple
    of methods (at least), so let's leave that alone for now...

    Signed-off-by: Al Viro

    Al Viro
     

13 Jul, 2012

1 commit


30 May, 2012

1 commit

  • pass inode + parent's inode or NULL instead of dentry + bool saying
    whether we want the parent or not.

    NOTE: that needs ceph fix folded in.

    Signed-off-by: Al Viro

    Al Viro
     

21 Mar, 2012

1 commit


09 Jan, 2012

1 commit


04 Jan, 2012

2 commits

  • situation with mount options is the same as for udf

    Signed-off-by: Al Viro

    Al Viro
     
  • Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
    it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
    the cost of taking it into inode_init_always() will be negligible for pipes
    and sockets and negative for everything else. Not to mention the removal of
    boilerplate code from ->destroy_inode() instances...

    Signed-off-by: Al Viro

    Al Viro
     

03 Nov, 2011

2 commits

  • Says Andrew:

    "60 patches. That's good enough for -rc1 I guess. I have quite a lot
    of detritus to be rechecked, work through maintainers, etc.

    - most of the remains of MM
    - rtc
    - various misc
    - cgroups
    - memcg
    - cpusets
    - procfs
    - ipc
    - rapidio
    - sysctl
    - pps
    - w1
    - drivers/misc
    - aio"

    * akpm: (60 commits)
    memcg: replace ss->id_lock with a rwlock
    aio: allocate kiocbs in batches
    drivers/misc/vmw_balloon.c: fix typo in code comment
    drivers/misc/vmw_balloon.c: determine page allocation flag can_sleep outside loop
    w1: disable irqs in critical section
    drivers/w1/w1_int.c: multiple masters used same init_name
    drivers/power/ds2780_battery.c: fix deadlock upon insertion and removal
    drivers/power/ds2780_battery.c: add a nolock function to w1 interface
    drivers/power/ds2780_battery.c: create central point for calling w1 interface
    w1: ds2760 and ds2780, use ida for id and ida_simple_get() to get it
    pps gpio client: add missing dependency
    pps: new client driver using GPIO
    pps: default echo function
    include/linux/dma-mapping.h: add dma_zalloc_coherent()
    sysctl: make CONFIG_SYSCTL_SYSCALL default to n
    sysctl: add support for poll()
    RapidIO: documentation update
    drivers/net/rionet.c: fix ethernet address macros for LE platforms
    RapidIO: fix potential null deref in rio_setup_device()
    RapidIO: add mport driver for Tsi721 bridge
    ...

    Linus Torvalds
     
  • Use mpage_readpages() instead of multiple calls to isofs_readpage() to
    reduce the CPU utilization and make performance higher.

    Signed-off-by: Namjae Jeon
    Cc: Al Viro
    Cc: Jan Kara
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Namjae Jeon
     

02 Nov, 2011

1 commit


23 Jul, 2011

1 commit

  • sbi->s_mutex isn't needed for isofs at all so we can just remove it. Generally,
    since isofs is always mounted read-only, filesystem structure cannot change
    under us. So buffer_head contents stays constant after it's filled in. That
    leaves us with possible changes of global data structures. Superblock changes
    only during filesystem mount (even remount does not change it), inodes are only
    filled in during reading from disk. So there are no changes of these structures
    to bother about.

    Arguments why sbi->s_mutex can be removed at each place:
    isofs_readdir: Accesses sb, inode, filp, local variables => s_mutex not needed
    isofs_lookup: Protected by directory's i_mutex. Accesses sb, inode, dentry,
    local variables => s_mutex not needed
    rock_ridge_symlink_readpage: Protected by page lock. Accesses sb, inode,
    local variables => s_mutex not needed.

    Signed-off-by: Jan Kara
    Signed-off-by: Al Viro

    Jan Kara
     

20 Jul, 2011

1 commit


18 Jun, 2011

1 commit


25 Mar, 2011

1 commit

  • * 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
    Documentation/iostats.txt: bit-size reference etc.
    cfq-iosched: removing unnecessary think time checking
    cfq-iosched: Don't clear queue stats when preempt.
    blk-throttle: Reset group slice when limits are changed
    blk-cgroup: Only give unaccounted_time under debug
    cfq-iosched: Don't set active queue in preempt
    block: fix non-atomic access to genhd inflight structures
    block: attempt to merge with existing requests on plug flush
    block: NULL dereference on error path in __blkdev_get()
    cfq-iosched: Don't update group weights when on service tree
    fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
    block: Require subsystems to explicitly allocate bio_set integrity mempool
    jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
    jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
    fs: make fsync_buffers_list() plug
    mm: make generic_writepages() use plugging
    blk-cgroup: Add unaccounted time to timeslice_used.
    block: fixup plugging stubs for !CONFIG_BLOCK
    block: remove obsolete comments for blkdev_issue_zeroout.
    blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
    ...

    Fix up conflicts in fs/{aio.c,super.c}

    Linus Torvalds
     

14 Mar, 2011

1 commit

  • The exportfs encode handle function should return the minimum required
    handle size. This helps user to find out the handle size by passing 0
    handle size in the first step and then redoing to the call again with
    the returned handle size value.

    Acked-by: Serge Hallyn
    Signed-off-by: Aneesh Kumar K.V
    Signed-off-by: Al Viro

    Aneesh Kumar K.V
     

10 Mar, 2011

1 commit

  • Code has been converted over to the new explicit on-stack plugging,
    and delay users have been converted to use the new API for that.
    So lets kill off the old plugging along with aops->sync_page().

    Signed-off-by: Jens Axboe

    Jens Axboe
     

13 Jan, 2011

1 commit


07 Jan, 2011

4 commits

  • Reduce some branches and memory accesses in dcache lookup by adding dentry
    flags to indicate common d_ops are set, rather than having to check them.
    This saves a pointer memory access (dentry->d_op) in common path lookup
    situations, and saves another pointer load and branch in cases where we
    have d_op but not the particular operation.

    Patched with:

    git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i

    Signed-off-by: Nick Piggin

    Nick Piggin
     
  • RCU free the struct inode. This will allow:

    - Subsequent store-free path walking patch. The inode must be consulted for
    permissions when walking, so an RCU inode reference is a must.
    - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
    to take i_lock no longer need to take sb_inode_list_lock to walk the list in
    the first place. This will simplify and optimize locking.
    - Could remove some nested trylock loops in dcache code
    - Could potentially simplify things a bit in VM land. Do not need to take the
    page lock to follow page->mapping.

    The downsides of this is the performance cost of using RCU. In a simple
    creat/unlink microbenchmark, performance drops by about 10% due to inability to
    reuse cache-hot slab objects. As iterations increase and RCU freeing starts
    kicking over, this increases to about 20%.

    In cases where inode lifetimes are longer (ie. many inodes may be allocated
    during the average life span of a single inode), a lot of this cache reuse is
    not applicable, so the regression caused by this patch is smaller.

    The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
    however this adds some complexity to list walking and store-free path walking,
    so I prefer to implement this at a later date, if it is shown to be a win in
    real situations. I haven't found a regression in any non-micro benchmark so I
    doubt it will be a problem.

    Signed-off-by: Nick Piggin

    Nick Piggin
     
  • Change d_hash so it may be called from lock-free RCU lookups. See similar
    patch for d_compare for details.

    For in-tree filesystems, this is just a mechanical change.

    Signed-off-by: Nick Piggin

    Nick Piggin
     
  • Change d_compare so it may be called from lock-free RCU lookups. This
    does put significant restrictions on what may be done from the callback,
    however there don't seem to have been any problems with in-tree fses.
    If some strange use case pops up that _really_ cannot cope with the
    rcu-walk rules, we can just add new rcu-unaware callbacks, which would
    cause name lookup to drop out of rcu-walk mode.

    For in-tree filesystems, this is just a mechanical change.

    Signed-off-by: Nick Piggin

    Nick Piggin
     

29 Oct, 2010

1 commit


28 Oct, 2010

1 commit


26 Oct, 2010

1 commit

  • Currently isofs_get_blocks() was limited to handle only 4TB files on 32-bit
    architectures because of unnecessary use of iblock variable which was signed
    long. Just remove the variable. The error messages that were using this
    variable should have rather used b_off anyway because that is the block we
    are currently mapping.

    Signed-off-by: Jan Kara
    Signed-off-by: Al Viro

    Jan Kara
     

05 Oct, 2010

2 commits

  • As in other file systems, we can replace the big kernel lock
    with a private mutex in isofs. This means we can now access
    multiple file systems concurrently, but it also means that
    we serialize readdir and lookup across sleeping operations
    which previously released the big kernel lock. This should
    not matter though, as these operations are in practice
    serialized through the hardware access.

    The isofs_get_blocks functions now does not take any lock
    any more, it used to recursively get the BKL. After looking
    at the code for hours, I convinced myself that it was never
    needed here anyway, because it only reads constant fields
    of the inode and writes to a buffer head array that is
    at this time only visible to the caller.

    The get_sb and fill_super operations do not need the locking
    at all because they operate on a file system that is either
    about to be created or to be destroyed but in either case
    is not visible to other threads.

    Signed-off-by: Arnd Bergmann

    Arnd Bergmann
     
  • This patch is a preparation necessary to remove the BKL from do_new_mount().
    It explicitly adds calls to lock_kernel()/unlock_kernel() around
    get_sb/fill_super operations for filesystems that still uses the BKL.

    I've read through all the code formerly covered by the BKL inside
    do_kern_mount() and have satisfied myself that it doesn't need the BKL
    any more.

    do_kern_mount() is already called without the BKL when mounting the rootfs
    and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
    from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
    through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
    afs_mntpt_follow_link(). Both later functions are actually the filesystems
    follow_link inode operation. vfs_kern_mount() is calling the specified
    get_sb function and lets the filesystem do its job by calling the given
    fill_super function.

    Therefore I think it is safe to push down the BKL from the VFS to the
    low-level filesystems get_sb/fill_super operation.

    [arnd: do not add the BKL to those file systems that already
    don't use it elsewhere]

    Signed-off-by: Jan Blunck
    Signed-off-by: Arnd Bergmann
    Cc: Matthew Wilcox
    Cc: Christoph Hellwig

    Jan Blunck
     

11 Aug, 2010

1 commit

  • isofs supports files larger than 4 GB by using multi-extent files.
    However an lseek() to a position beyond 4 GB in such a file will
    fail with EINVAL, because s_maxbytes in the isofs superblock is
    initialized to 2^32-1, and generic_file_llseek() checks against
    that value.

    I therefore suggest increasing the value of s_maxbytes to have
    full support for large files in isofs. With multi-extent files, file
    size is only limited by the maximum size of the file system (8 TB),
    so this seems a reasonable value for s_maxbytes.

    Signed-off-by: Jan Andres
    Signed-off-by: Al Viro

    Jan Andres