15 Jan, 2016

1 commit

  • Mark those kmem allocations that are known to be easily triggered from
    userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
    memcg. For the list, see below:

    - threadinfo
    - task_struct
    - task_delay_info
    - pid
    - cred
    - mm_struct
    - vm_area_struct and vm_region (nommu)
    - anon_vma and anon_vma_chain
    - signal_struct
    - sighand_struct
    - fs_struct
    - files_struct
    - fdtable and fdtable->full_fds_bits
    - dentry and external_name
    - inode for all filesystems. This is the most tedious part, because
    most filesystems overwrite the alloc_inode method.

    The list is far from complete, so feel free to add more objects.
    Nevertheless, it should be close to "account everything" approach and
    keep most workloads within bounds. Malevolent users will be able to
    breach the limit, but this was possible even with the former "account
    everything" approach (simply because it did not account everything in
    fact).

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Vladimir Davydov
    Acked-by: Johannes Weiner
    Acked-by: Michal Hocko
    Cc: Tejun Heo
    Cc: Greg Thelen
    Cc: Christoph Lameter
    Cc: Pekka Enberg
    Cc: David Rientjes
    Cc: Joonsoo Kim
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Vladimir Davydov
     

31 Dec, 2015

1 commit


09 Dec, 2015

2 commits

  • new method: ->get_link(); replacement of ->follow_link(). The differences
    are:
    * inode and dentry are passed separately
    * might be called both in RCU and non-RCU mode;
    the former is indicated by passing it a NULL dentry.
    * when called that way it isn't allowed to block
    and should return ERR_PTR(-ECHILD) if it needs to be called
    in non-RCU mode.

    It's a flagday change - the old method is gone, all in-tree instances
    converted. Conversion isn't hard; said that, so far very few instances
    do not immediately bail out when called in RCU mode. That'll change
    in the next commits.

    Signed-off-by: Al Viro

    Al Viro
     
  • kmap() in page_follow_link_light() needed to go - allowing to hold
    an arbitrary number of kmaps for long is a great way to deadlocking
    the system.

    new helper (inode_nohighmem(inode)) needs to be used for pagecache
    symlinks inodes; done for all in-tree cases. page_follow_link_light()
    instrumented to yell about anything missed.

    Signed-off-by: Al Viro

    Al Viro
     

26 Jun, 2015

1 commit


16 Apr, 2015

1 commit


09 Aug, 2014

1 commit

  • The original minix zmap blocks calculation was correct, in the formula of:

    sbi->s_nzones - sbi->s_firstdatazone + 1

    It is

    sp->s_zones - (sp->s_firstdatazone - 1)

    in the minix3 source code.

    But a later commit 016e8d44bc06 ("fs/minix: Verify bitmap block counts
    before mounting") has changed it unfortunately as:

    sbi->s_nzones - (sbi->s_firstdatazone + 1)

    This would show free blocks one block less than the real when the total
    data blocks are in "full zmap blocks plus one".

    This patch corrects that zmap blocks calculation and tidy a printk
    message while at it.

    Signed-off-by: Qi Yong
    Cc: Josh Boyer
    Cc: Al Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Qi Yong
     

05 Apr, 2014

1 commit

  • Pull ext4 updates from Ted Ts'o:
    "Major changes for 3.14 include support for the newly added ZERO_RANGE
    and COLLAPSE_RANGE fallocate operations, and scalability improvements
    in the jbd2 layer and in xattr handling when the extended attributes
    spill over into an external block.

    Other than that, the usual clean ups and minor bug fixes"

    * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (42 commits)
    ext4: fix premature freeing of partial clusters split across leaf blocks
    ext4: remove unneeded test of ret variable
    ext4: fix comment typo
    ext4: make ext4_block_zero_page_range static
    ext4: atomically set inode->i_flags in ext4_set_inode_flags()
    ext4: optimize Hurd tests when reading/writing inodes
    ext4: kill i_version support for Hurd-castrated file systems
    ext4: each filesystem creates and uses its own mb_cache
    fs/mbcache.c: doucple the locking of local from global data
    fs/mbcache.c: change block and index hash chain to hlist_bl_node
    ext4: Introduce FALLOC_FL_ZERO_RANGE flag for fallocate
    ext4: refactor ext4_fallocate code
    ext4: Update inode i_size after the preallocation
    ext4: fix partial cluster handling for bigalloc file systems
    ext4: delete path dealloc code in ext4_ext_handle_uninitialized_extents
    ext4: only call sync_filesystm() when remounting read-only
    fs: push sync_filesystem() down to the file system's remount_fs()
    jbd2: improve error messages for inconsistent journal heads
    jbd2: minimize region locked by j_list_lock in jbd2_journal_forget()
    jbd2: minimize region locked by j_list_lock in journal_get_create_access()
    ...

    Linus Torvalds
     

04 Apr, 2014

2 commits

  • init_inodecache is only called by __init init_minix_fs.

    Signed-off-by: Fabian Frederick
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Fabian Frederick
     
  • Reclaim will be leaving shadow entries in the page cache radix tree upon
    evicting the real page. As those pages are found from the LRU, an
    iput() can lead to the inode being freed concurrently. At this point,
    reclaim must no longer install shadow pages because the inode freeing
    code needs to ensure the page tree is really empty.

    Add an address_space flag, AS_EXITING, that the inode freeing code sets
    under the tree lock before doing the final truncate. Reclaim will check
    for this flag before installing shadow pages.

    Signed-off-by: Johannes Weiner
    Reviewed-by: Rik van Riel
    Reviewed-by: Minchan Kim
    Cc: Andrea Arcangeli
    Cc: Bob Liu
    Cc: Christoph Hellwig
    Cc: Dave Chinner
    Cc: Greg Thelen
    Cc: Hugh Dickins
    Cc: Jan Kara
    Cc: KOSAKI Motohiro
    Cc: Luigi Semenzato
    Cc: Mel Gorman
    Cc: Metin Doslu
    Cc: Michel Lespinasse
    Cc: Ozgun Erdogan
    Cc: Peter Zijlstra
    Cc: Roman Gushchin
    Cc: Ryan Mallon
    Cc: Tejun Heo
    Cc: Vlastimil Babka
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Johannes Weiner
     

13 Mar, 2014

1 commit

  • Previously, the no-op "mount -o mount /dev/xxx" operation when the
    file system is already mounted read-write causes an implied,
    unconditional syncfs(). This seems pretty stupid, and it's certainly
    documented or guaraunteed to do this, nor is it particularly useful,
    except in the case where the file system was mounted rw and is getting
    remounted read-only.

    However, it's possible that there might be some file systems that are
    actually depending on this behavior. In most file systems, it's
    probably fine to only call sync_filesystem() when transitioning from
    read-write to read-only, and there are some file systems where this is
    not needed at all (for example, for a pseudo-filesystem or something
    like romfs).

    Signed-off-by: "Theodore Ts'o"
    Cc: linux-fsdevel@vger.kernel.org
    Cc: Christoph Hellwig
    Cc: Artem Bityutskiy
    Cc: Adrian Hunter
    Cc: Evgeniy Dushistov
    Cc: Jan Kara
    Cc: OGAWA Hirofumi
    Cc: Anders Larsen
    Cc: Phillip Lougher
    Cc: Kees Cook
    Cc: Mikulas Patocka
    Cc: Petr Vandrovec
    Cc: xfs@oss.sgi.com
    Cc: linux-btrfs@vger.kernel.org
    Cc: linux-cifs@vger.kernel.org
    Cc: samba-technical@lists.samba.org
    Cc: codalist@coda.cs.cmu.edu
    Cc: linux-ext4@vger.kernel.org
    Cc: linux-f2fs-devel@lists.sourceforge.net
    Cc: fuse-devel@lists.sourceforge.net
    Cc: cluster-devel@redhat.com
    Cc: linux-mtd@lists.infradead.org
    Cc: jfs-discussion@lists.sourceforge.net
    Cc: linux-nfs@vger.kernel.org
    Cc: linux-nilfs@vger.kernel.org
    Cc: linux-ntfs-dev@lists.sourceforge.net
    Cc: ocfs2-devel@oss.oracle.com
    Cc: reiserfs-devel@vger.kernel.org

    Theodore Ts'o
     

13 Sep, 2013

1 commit


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
     

21 Dec, 2012

1 commit


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


06 May, 2012

1 commit

  • After we moved inode_sync_wait() from end_writeback() it doesn't make sense
    to call the function end_writeback() anymore. Rename it to clear_inode()
    which well says what the function really does - set I_CLEAR flag.

    Signed-off-by: Jan Kara
    Signed-off-by: Fengguang Wu

    Jan Kara
     

21 Mar, 2012

2 commits


09 Jan, 2012

1 commit

  • * 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits)
    reiserfs: Properly display mount options in /proc/mounts
    vfs: prevent remount read-only if pending removes
    vfs: count unlinked inodes
    vfs: protect remounting superblock read-only
    vfs: keep list of mounts for each superblock
    vfs: switch ->show_options() to struct dentry *
    vfs: switch ->show_path() to struct dentry *
    vfs: switch ->show_devname() to struct dentry *
    vfs: switch ->show_stats to struct dentry *
    switch security_path_chmod() to struct path *
    vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
    vfs: trim includes a bit
    switch mnt_namespace ->root to struct mount
    vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
    vfs: opencode mntget() mnt_set_mountpoint()
    vfs: spread struct mount - remaining argument of next_mnt()
    vfs: move fsnotify junk to struct mount
    vfs: move mnt_devname
    vfs: move mnt_list to struct mount
    vfs: switch pnode.h macros to struct mount *
    ...

    Linus Torvalds
     

05 Jan, 2012

1 commit

  • bitmap size sanity checks should be done *before* allocating ->s_root;
    there their cleanup on failure would be correct. As it is, we do iput()
    on root inode, but leak the root dentry...

    Signed-off-by: Al Viro
    Acked-by: Josh Boyer
    Signed-off-by: Linus Torvalds

    Al Viro
     

04 Jan, 2012

1 commit

  • 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
     

20 Nov, 2011

1 commit

  • Newer versions of MINIX can create filesystems that allocate an extra
    bitmap block. Mounting of this succeeds, but doing a statfs call will
    result in an oops in count_free because of a negative number being used
    for the bh index.

    Avoid this by verifying the number of allocated blocks at mount time,
    erroring out if there are not enough and make statfs ignore the extras
    if there are too many.

    This fixes https://bugzilla.kernel.org/show_bug.cgi?id=18792

    Signed-off-by: Josh Boyer
    Signed-off-by: Al Viro

    Josh Boyer
     

02 Nov, 2011

1 commit


21 Jul, 2011

1 commit


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
     

07 Jan, 2011

1 commit

  • 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
     

29 Oct, 2010

1 commit


10 Aug, 2010

4 commits

  • We need to wait for completion of possible writeback in progress
    before we clear on-disk inode during deletion.

    Signed-off-by: Al Viro

    Al Viro
     
  • Move the call to vmtruncate to get rid of accessive blocks to the callers
    in preparation of the new truncate sequence and rename the non-truncating
    version to block_write_begin.

    While we're at it also remove several unused arguments to block_write_begin.

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

    Christoph Hellwig
     
  • Split up the block_write_begin implementation - __block_write_begin is a new
    trivial wrapper for block_prepare_write that always takes an already
    allocated page and can be either called from block_write_begin or filesystem
    code that already has a page allocated. Remove the handling of already
    allocated pages from block_write_begin after switching all callers that
    do it to __block_write_begin.

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

    Christoph Hellwig
     
  • For filesystem that implement directories in pagecache we call
    block_write_begin with an already allocated page for this code, while the
    normal regular file write path uses the default block_write_begin behaviour.

    Get rid of the __foofs_write_begin helper and opencode the normal write_begin
    call in foofs_write_begin, while adding a new foofs_prepare_chunk helper for
    the directory code. The added benefit is that foofs_prepare_chunk has
    a much saner calling convention.

    Note that the interruptible flag passed into block_write_begin is always
    ignored if we already pass in a page (see next patch for details), and
    we never were doing truncations of exessive blocks for this case either so we
    can switch directly to block_write_begin_newtrunc.

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

    Christoph Hellwig
     

06 Mar, 2010

1 commit

  • This gives the filesystem more information about the writeback that
    is happening. Trond requested this for the NFS unstable write handling,
    and other filesystems might benefit from this too by beeing able to
    distinguish between the different callers in more detail.

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

    Christoph Hellwig
     

17 Jun, 2009

1 commit


12 Jun, 2009

2 commits

  • * get minix_write_inode() to honour the second argument
    * now we can use simple_fsync() for minixfs

    Signed-off-by: Al Viro

    Al Viro
     
  • Move BKL into ->put_super from the only caller. A couple of
    filesystems had trivial enough ->put_super (only kfree and NULLing of
    s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
    hugetlbfs, omfs, qnx4, shmem, all others got the full treatment. Most
    of them probably don't need it, but I'd rather sort that out individually.
    Preferably after all the other BKL pushdowns in that area.

    [AV: original used to move lock_super() down as well; these changes are
    removed since we don't do lock_super() at all in generic_shutdown_super()
    now]
    [AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]

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

    Christoph Hellwig
     

03 Apr, 2009

1 commit


23 Mar, 2009

1 commit


27 Jul, 2008

1 commit

  • Kmem cache passed to constructor is only needed for constructors that are
    themselves multiplexeres. Nobody uses this "feature", nor does anybody uses
    passed kmem cache in non-trivial way, so pass only pointer to object.

    Non-trivial places are:
    arch/powerpc/mm/init_64.c
    arch/powerpc/mm/hugetlbpage.c

    This is flag day, yes.

    Signed-off-by: Alexey Dobriyan
    Acked-by: Pekka Enberg
    Acked-by: Christoph Lameter
    Cc: Jon Tollefson
    Cc: Nick Piggin
    Cc: Matt Mackall
    [akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
    [akpm@linux-foundation.org: fix mm/slab.c]
    [akpm@linux-foundation.org: fix ubifs]
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan