linux-stable.git/fs, branch linux-4.15.y

ovl: set lower layer st_dev only if setting lower st_ino

2018-04-19T06:55:13+00:00

commit 9f99e50d460ac7fd5f6c9b97aad0088c28c8656d upstream.

For broken hardlinks, we do not return lower st_ino, so we should
also not return lower pseudo st_dev.

Fixes: a0c5ad307ac0 ("ovl: relax same fs constraint for constant st_ino")
Cc:  #v4.15
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Amir Goldstein 
Signed-off-by: Greg Kroah-Hartman

getname_kernel() needs to make sure that ->name != ->iname in long case

2018-04-19T06:55:12+00:00

commit 30ce4d1903e1d8a7ccd110860a5eef3c638ed8be upstream.

missed it in "kill struct filename.separate" several years ago.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

nfsd: fix incorrect umasks

2018-04-19T06:55:11+00:00

commit 880a3a5325489a143269a8e172e7563ebf9897bc upstream.

We're neglecting to clear the umask after it's set, which can cause a
later unrelated rpc to (incorrectly) use the same umask if it happens to
be processed by the same thread.

There's a more subtle problem here too:

An NFSv4 compound request is decoded all in one pass before any
operations are executed.

Currently we're setting current->fs->umask at the time we decode the
compound.  In theory a single compound could contain multiple creates
each setting a umask.  In that case we'd end up using whichever umask
was passed in the *last* operation as the umask for all the creates,
whether that was correct or not.

So, we should just be saving the umask at decode time and waiting to set
it until we actually process the corresponding operation.

In practice it's unlikely any client would do multiple creates in a
single compound.  And even if it did they'd likely be from the same
process (hence carry the same umask).  So this is a little academic, but
we should get it right anyway.

Fixes: 47057abde515 (nfsd: add support for the umask attribute)
Cc: stable@vger.kernel.org
Reported-by: Lucash Stach 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

hugetlbfs: fix bug in pgoff overflow checking

2018-04-19T06:55:11+00:00

commit 5df63c2a149ae65a9ec239e7c2af44efa6f79beb upstream.

This is a fix for a regression in 32 bit kernels caused by an invalid
check for pgoff overflow in hugetlbfs mmap setup.  The check incorrectly
specified that the size of a loff_t was the same as the size of a long.
The regression prevents mapping hugetlbfs files at offsets greater than
4GB on 32 bit kernels.

On 32 bit kernels conversion from a page based unsigned long can not
overflow a loff_t byte offset.  Therefore, skip this check if
sizeof(unsigned long) != sizeof(loff_t).

Link: http://lkml.kernel.org/r/20180330145402.5053-1-mike.kravetz@oracle.com
Fixes: 63489f8e8211 ("hugetlbfs: check for pgoff value overflow")
Reported-by: Dan Rue 
Signed-off-by: Mike Kravetz 
Tested-by: Anders Roxell 
Cc: Michal Hocko 
Cc: Yisheng Xie 
Cc: "Kirill A . Shutemov" 
Cc: Nic Losby 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ovl: fix lookup with middle layer opaque dir and absolute path redirects

2018-04-19T06:55:10+00:00

commit 3ec9b3fafcaf441cc4d46b9742cd6ec0c79f8df0 upstream.

As of now if we encounter an opaque dir while looking for a dentry, we set
d->last=true. This means that there is no need to look further in any of
the lower layers. This works fine as long as there are no redirets or
relative redircts. But what if there is an absolute redirect on the
children dentry of opaque directory. We still need to continue to look into
next lower layer. This patch fixes it.

Here is an example to demonstrate the issue. Say you have following setup.

upper:  /redirect (redirect=/a/b/c)
lower1: /a/[b]/c       ([b] is opaque) (c has absolute redirect=/a/b/d/)
lower0: /a/b/d/foo

Now "redirect" dir should merge with lower1:/a/b/c/ and lower0:/a/b/d.
Note, despite the fact lower1:/a/[b] is opaque, we need to continue to look
into lower0 because children c has an absolute redirect.

Following is a reproducer.

Watch me make foo disappear:

 $ mkdir lower middle upper work work2 merged
 $ mkdir lower/origin
 $ touch lower/origin/foo
 $ mount -t overlay none merged/ \
         -olowerdir=lower,upperdir=middle,workdir=work2
 $ mkdir merged/pure
 $ mv merged/origin merged/pure/redirect
 $ umount merged
 $ mount -t overlay none merged/ \
         -olowerdir=middle:lower,upperdir=upper,workdir=work
 $ mv merged/pure/redirect merged/redirect

Now you see foo inside a twice redirected merged dir:

 $ ls merged/redirect
 foo
 $ umount merged
 $ mount -t overlay none merged/ \
         -olowerdir=middle:lower,upperdir=upper,workdir=work

After mount cycle you don't see foo inside the same dir:

 $ ls merged/redirect

During middle layer lookup, the opaqueness of middle/pure is left in
the lookup state and then middle/pure/redirect is wrongly treated as
opaque.

Fixes: 02b69b284cd7 ("ovl: lookup redirects")
Cc:  #v4.10
Signed-off-by: Amir Goldstein 
Signed-off-by: Vivek Goyal 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

f2fs: fix heap mode to reset it back

2018-04-19T06:55:10+00:00

commit b94929d975c8423defc9aededb0f499ff936b509 upstream.

Commit 7a20b8a61eff81bdb7097a578752a74860e9d142 ("f2fs: allocate node
and hot data in the beginning of partition") introduces another mount
option, heap, to reset it back. But it does not do anything for heap
mode, so fix it.

Cc: stable@vger.kernel.org
Signed-off-by: Yunlong Song 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Greg Kroah-Hartman

f2fs: fix lock dependency in between dio_rwsem & i_mmap_sem

2018-04-12T10:31:04+00:00

[ Upstream commit 21020812c9e1ab593367fad9ce579f842a0b406d ]

test/generic/208 reports a potential deadlock as below:

Chain exists of:
  &mm->mmap_sem --> &fi->i_mmap_sem --> &fi->dio_rwsem[WRITE]

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&fi->dio_rwsem[WRITE]);
                               lock(&fi->i_mmap_sem);
                               lock(&fi->dio_rwsem[WRITE]);
  lock(&mm->mmap_sem);

This patch changes the lock dependency as below in fallocate() to
fix this issue:
- dio_rwsem
 - i_mmap_sem

Fixes: bb06664a534b ("f2fs: avoid race in between GC and block exchange")
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

VFS: close race between getcwd() and d_move()

2018-04-12T10:31:03+00:00

[ Upstream commit 61647823aa920e395afcce4b57c32afb51456cab ]

d_move() will call __d_drop() and then __d_rehash()
on the dentry being moved.  This creates a small window
when the dentry appears to be unhashed.  Many tests
of d_unhashed() are made under ->d_lock and so are safe
from racing with this window, but some aren't.
In particular, getcwd() calls d_unlinked() (which calls
d_unhashed()) without d_lock protection, so it can race.

This races has been seen in practice with lustre, which uses d_move() as
part of name lookup.  See:
   https://jira.hpdd.intel.com/browse/LU-9735
It could race with a regular rename(), and result in ENOENT instead
of either the 'before' or 'after' name.

The race can be demonstrated with a simple program which
has two threads, one renaming a directory back and forth
while another calls getcwd() within that directory: it should never
fail, but does.  See:
  https://patchwork.kernel.org/patch/9455345/

We could fix this race by taking d_lock and rechecking when
d_unhashed() reports true.  Alternately when can remove the window,
which is the approach this patch takes.

___d_drop() is introduce which does *not* clear d_hash.pprev
so the dentry still appears to be hashed.  __d_drop() calls
___d_drop(), then clears d_hash.pprev.
__d_move() now uses ___d_drop() and only clears d_hash.pprev
when not rehashing.

Signed-off-by: NeilBrown 
Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

Btrfs: fix unexpected cow in run_delalloc_nocow

2018-04-08T12:27:39+00:00

commit 5811375325420052fcadd944792a416a43072b7f upstream.

Fstests generic/475 provides a way to fail metadata reads while
checking if checksum exists for the inode inside run_delalloc_nocow(),
and csum_exist_in_range() interprets error (-EIO) as inode having
checksum and makes its caller enter the cow path.

In case of free space inode, this ends up with a warning in
cow_file_range().

The same problem applies to btrfs_cross_ref_exist() since it may also
read metadata in between.

With this, run_delalloc_nocow() bails out when errors occur at the two
places.

cc:  v2.6.28+
Fixes: 17d217fe970d ("Btrfs: fix nodatasum handling in balancing code")
Signed-off-by: Liu Bo 
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

ceph: only dirty ITER_IOVEC pages for direct read

2018-04-08T12:27:33+00:00

commit 85784f9395987a422fa04263e7c0fb13da11eb5c upstream.

If a page is already locked, attempting to dirty it leads to a deadlock
in lock_page().  This is what currently happens to ITER_BVEC pages when
a dio-enabled loop device is backed by ceph:

  $ losetup --direct-io /dev/loop0 /mnt/cephfs/img
  $ xfs_io -c 'pread 0 4k' /dev/loop0

Follow other file systems and only dirty ITER_IOVEC pages.

Cc: stable@kernel.org
Signed-off-by: "Yan, Zheng" 
Reviewed-by: Ilya Dryomov 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman