linux-stable.git/fs/nilfs2, branch linux-3.14.y

fs/nilfs2: fix potential underflow in call to crc32_le

2016-08-10T08:21:02+00:00

commit 63d2f95d63396059200c391ca87161897b99e74a upstream.

The value `bytes' comes from the filesystem which is about to be
mounted.  We cannot trust that the value is always in the range we
expect it to be.

Check its value before using it to calculate the length for the crc32_le
call.  It value must be larger (or equal) sumoff + 4.

This fixes a kernel bug when accidentially mounting an image file which
had the nilfs2 magic value 0x3434 at the right offset 0x406 by chance.
The bytes 0x01 0x00 were stored at 0x408 and were interpreted as a
s_bytes value of 1.  This caused an underflow when substracting sumoff +
4 (20) in the call to crc32_le.

  BUG: unable to handle kernel paging request at ffff88021e600000
  IP:  crc32_le+0x36/0x100
  ...
  Call Trace:
    nilfs_valid_sb.part.5+0x52/0x60 [nilfs2]
    nilfs_load_super_block+0x142/0x300 [nilfs2]
    init_nilfs+0x60/0x390 [nilfs2]
    nilfs_mount+0x302/0x520 [nilfs2]
    mount_fs+0x38/0x160
    vfs_kern_mount+0x67/0x110
    do_mount+0x269/0xe00
    SyS_mount+0x9f/0x100
    entry_SYSCALL_64_fastpath+0x16/0x71

Link: http://lkml.kernel.org/r/1466778587-5184-2-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Torsten Hilbrich 
Tested-by: Torsten Hilbrich 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nilfs2: fix sanity check of btree level in nilfs_btree_root_broken()

2015-05-17T16:53:49+00:00

commit d8fd150fe3935e1692bf57c66691e17409ebb9c1 upstream.

The range check for b-tree level parameter in nilfs_btree_root_broken()
is wrong; it accepts the case of "level == NILFS_BTREE_LEVEL_MAX" even
though the level is limited to values in the range of 0 to
(NILFS_BTREE_LEVEL_MAX - 1).

Since the level parameter is read from storage device and used to index
nilfs_btree_path array whose element count is NILFS_BTREE_LEVEL_MAX, it
can cause memory overrun during btree operations if the boundary value
is set to the level parameter on device.

This fixes the broken sanity check and adds a comment to clarify that
the upper bound NILFS_BTREE_LEVEL_MAX is exclusive.

Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nilfs2: fix deadlock of segment constructor during recovery

2015-03-26T14:06:56+00:00

commit 283ee1482f349d6c0c09dfb725db5880afc56813 upstream.

According to a report from Yuxuan Shui, nilfs2 in kernel 3.19 got stuck
during recovery at mount time.  The code path that caused the deadlock was
as follows:

  nilfs_fill_super()
    load_nilfs()
      nilfs_salvage_orphan_logs()
        * Do roll-forwarding, attach segment constructor for recovery,
          and kick it.

        nilfs_segctor_thread()
          nilfs_segctor_thread_construct()
           * A lock is held with nilfs_transaction_lock()
             nilfs_segctor_do_construct()
               nilfs_segctor_drop_written_files()
                 iput()
                   iput_final()
                     write_inode_now()
                       writeback_single_inode()
                         __writeback_single_inode()
                           do_writepages()
                             nilfs_writepage()
                               nilfs_construct_dsync_segment()
                                 nilfs_transaction_lock() --> deadlock

This can happen if commit 7ef3ff2fea8b ("nilfs2: fix deadlock of segment
constructor over I_SYNC flag") is applied and roll-forward recovery was
performed at mount time.  The roll-forward recovery can happen if datasync
write is done and the file system crashes immediately after that.  For
instance, we can reproduce the issue with the following steps:

 < nilfs2 is mounted on /nilfs (device: /dev/sdb1) >
 # dd if=/dev/zero of=/nilfs/test bs=4k count=1 && sync
 # dd if=/dev/zero of=/nilfs/test conv=notrunc oflag=dsync bs=4k
 count=1 && reboot -nfh
 < the system will immediately reboot >
 # mount -t nilfs2 /dev/sdb1 /nilfs

The deadlock occurs because iput() can run segment constructor through
writeback_single_inode() if MS_ACTIVE flag is not set on sb->s_flags.  The
above commit changed segment constructor so that it calls iput()
asynchronously for inodes with i_nlink == 0, but that change was
imperfect.

This fixes the another deadlock by deferring iput() in segment constructor
even for the case that mount is not finished, that is, for the case that
MS_ACTIVE flag is not set.

Signed-off-by: Ryusuke Konishi 
Reported-by: Yuxuan Shui 
Tested-by: Ryusuke Konishi 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nilfs2: fix potential memory overrun on inode

2015-03-18T12:31:32+00:00

commit 957ed60b53b519064a54988c4e31e0087e47d091 upstream.

Each inode of nilfs2 stores a root node of a b-tree, and it turned out to
have a memory overrun issue:

Each b-tree node of nilfs2 stores a set of key-value pairs and the number
of them (in "bn_nchildren" member of nilfs_btree_node struct), as well as
a few other "bn_*" members.

Since the value of "bn_nchildren" is used for operations on the key-values
within the b-tree node, it can cause memory access overrun if a large
number is incorrectly set to "bn_nchildren".

For instance, nilfs_btree_node_lookup() function determines the range of
binary search with it, and too large "bn_nchildren" leads
nilfs_btree_node_get_key() in that function to overrun.

As for intermediate b-tree nodes, this is prevented by a sanity check
performed when each node is read from a drive, however, no sanity check
has been done for root nodes stored in inodes.

This patch fixes the issue by adding missing sanity check against b-tree
root nodes so that it's called when on-memory inodes are read from ifile,
inode metadata file.

Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nilfs2: fix deadlock of segment constructor over I_SYNC flag

2015-02-11T06:54:47+00:00

commit 7ef3ff2fea8bf5e4a21cef47ad87710a3d0fdb52 upstream.

Nilfs2 eventually hangs in a stress test with fsstress program.  This
issue was caused by the following deadlock over I_SYNC flag between
nilfs_segctor_thread() and writeback_sb_inodes():

  nilfs_segctor_thread()
    nilfs_segctor_thread_construct()
      nilfs_segctor_unlock()
        nilfs_dispose_list()
          iput()
            iput_final()
              evict()
                inode_wait_for_writeback()  * wait for I_SYNC flag

  writeback_sb_inodes()
     * set I_SYNC flag on inode->i_state
    __writeback_single_inode()
      do_writepages()
        nilfs_writepages()
          nilfs_construct_dsync_segment()
            nilfs_segctor_sync()
               * wait for completion of segment constructor
    inode_sync_complete()
       * clear I_SYNC flag after __writeback_single_inode() completed

writeback_sb_inodes() calls do_writepages() for dirty inodes after
setting I_SYNC flag on inode->i_state.  do_writepages() in turn calls
nilfs_writepages(), which can run segment constructor and wait for its
completion.  On the other hand, segment constructor calls iput(), which
can call evict() and wait for the I_SYNC flag on
inode_wait_for_writeback().

Since segment constructor doesn't know when I_SYNC will be set, it
cannot know whether iput() will block or not unless inode->i_nlink has a
non-zero count.  We can prevent evict() from being called in iput() by
implementing sop->drop_inode(), but it's not preferable to leave inodes
with i_nlink == 0 for long periods because it even defers file
truncation and inode deallocation.  So, this instead resolves the
deadlock by calling iput() asynchronously with a workqueue for inodes
with i_nlink == 0.

Signed-off-by: Ryusuke Konishi 
Cc: Al Viro 
Tested-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races

2015-01-16T14:59:33+00:00

commit 705304a863cc41585508c0f476f6d3ec28cf7e00 upstream.

Same story as in commit 41080b5a2401 ("nfsd race fixes: ext2") (similar
ext2 fix) except that nilfs2 needs to use insert_inode_locked4() instead
of insert_inode_locked() and a bug of a check for dead inodes needs to
be fixed.

If nilfs_iget() is called from nfsd after nilfs_new_inode() calls
insert_inode_locked4(), nilfs_iget() will wait for unlock_new_inode() at
the end of nilfs_mkdir()/nilfs_create()/etc to unlock the inode.

If nilfs_iget() is called before nilfs_new_inode() calls
insert_inode_locked4(), it will create an in-core inode and read its
data from the on-disk inode.  But, nilfs_iget() will find i_nlink equals
zero and fail at nilfs_read_inode_common(), which will lead it to call
iget_failed() and cleanly fail.

However, this sanity check doesn't work as expected for reused on-disk
inodes because they leave a non-zero value in i_mode field and it
hinders the test of i_nlink.  This patch also fixes the issue by
removing the test on i_mode that nilfs2 doesn't need.

Signed-off-by: Ryusuke Konishi 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nilfs2: fix data loss with mmap()

2014-10-05T21:52:21+00:00

commit 56d7acc792c0d98f38f22058671ee715ff197023 upstream.

This bug leads to reproducible silent data loss, despite the use of
msync(), sync() and a clean unmount of the file system.  It is easily
reproducible with the following script:

  ----------------[BEGIN SCRIPT]--------------------
  mkfs.nilfs2 -f /dev/sdb
  mount /dev/sdb /mnt

  dd if=/dev/zero bs=1M count=30 of=/mnt/testfile

  umount /mnt
  mount /dev/sdb /mnt
  CHECKSUM_BEFORE="$(md5sum /mnt/testfile)"

  /root/mmaptest/mmaptest /mnt/testfile 30 10 5

  sync
  CHECKSUM_AFTER="$(md5sum /mnt/testfile)"
  umount /mnt
  mount /dev/sdb /mnt
  CHECKSUM_AFTER_REMOUNT="$(md5sum /mnt/testfile)"
  umount /mnt

  echo "BEFORE MMAP:\t$CHECKSUM_BEFORE"
  echo "AFTER MMAP:\t$CHECKSUM_AFTER"
  echo "AFTER REMOUNT:\t$CHECKSUM_AFTER_REMOUNT"
  ----------------[END SCRIPT]--------------------

The mmaptest tool looks something like this (very simplified, with
error checking removed):

  ----------------[BEGIN mmaptest]--------------------
  data = mmap(NULL, file_size - file_offset, PROT_READ | PROT_WRITE,
              MAP_SHARED, fd, file_offset);

  for (i = 0; i < write_count; ++i) {
        memcpy(data + i * 4096, buf, sizeof(buf));
        msync(data, file_size - file_offset, MS_SYNC))
  }
  ----------------[END mmaptest]--------------------

The output of the script looks something like this:

  BEFORE MMAP:    281ed1d5ae50e8419f9b978aab16de83  /mnt/testfile
  AFTER MMAP:     6604a1c31f10780331a6850371b3a313  /mnt/testfile
  AFTER REMOUNT:  281ed1d5ae50e8419f9b978aab16de83  /mnt/testfile

So it is clear, that the changes done using mmap() do not survive a
remount.  This can be reproduced a 100% of the time.  The problem was
introduced in commit 136e8770cd5d ("nilfs2: fix issue of
nilfs_set_page_dirty() for page at EOF boundary").

If the page was read with mpage_readpage() or mpage_readpages() for
example, then it has no buffers attached to it.  In that case
page_has_buffers(page) in nilfs_set_page_dirty() will be false.
Therefore nilfs_set_file_dirty() is never called and the pages are never
collected and never written to disk.

This patch fixes the problem by also calling nilfs_set_file_dirty() if the
page has no buffers attached to it.

[akpm@linux-foundation.org: s/PAGE_SHIFT/PAGE_CACHE_SHIFT/]
Signed-off-by: Andreas Rohner 
Tested-by: Andreas Rohner 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block

2014-01-30T19:19:05+00:00

Pull core block IO changes from Jens Axboe:
 "The major piece in here is the immutable bio_ve series from Kent, the
  rest is fairly minor.  It was supposed to go in last round, but
  various issues pushed it to this release instead.  The pull request
  contains:

   - Various smaller blk-mq fixes from different folks.  Nothing major
     here, just minor fixes and cleanups.

   - Fix for a memory leak in the error path in the block ioctl code
     from Christian Engelmayer.

   - Header export fix from CaiZhiyong.

   - Finally the immutable biovec changes from Kent Overstreet.  This
     enables some nice future work on making arbitrarily sized bios
     possible, and splitting more efficient.  Related fixes to immutable
     bio_vecs:

        - dm-cache immutable fixup from Mike Snitzer.
        - btrfs immutable fixup from Muthu Kumar.

  - bio-integrity fix from Nic Bellinger, which is also going to stable"

* 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits)
  xtensa: fixup simdisk driver to work with immutable bio_vecs
  block/blk-mq-cpu.c: use hotcpu_notifier()
  blk-mq: for_each_* macro correctness
  block: Fix memory leak in rw_copy_check_uvector() handling
  bio-integrity: Fix bio_integrity_verify segment start bug
  block: remove unrelated header files and export symbol
  blk-mq: uses page->list incorrectly
  blk-mq: use __smp_call_function_single directly
  btrfs: fix missing increment of bi_remaining
  Revert "block: Warn and free bio if bi_end_io is not set"
  block: Warn and free bio if bi_end_io is not set
  blk-mq: fix initializing request's start time
  block: blk-mq: don't export blk_mq_free_queue()
  block: blk-mq: make blk_sync_queue support mq
  block: blk-mq: support draining mq queue
  dm cache: increment bi_remaining when bi_end_io is restored
  block: fixup for generic bio chaining
  block: Really silence spurious compiler warnings
  block: Silence spurious compiler warnings
  block: Kill bio_pair_split()
  ...

nilfs2: add comments for ioctls

2014-01-24T00:37:00+00:00

Add comments for ioctls in fs/nilfs2/ioctl.c file and describe NILFS2
specific ioctls in Documentation/filesystems/nilfs2.txt.

Signed-off-by: Vyacheslav Dubeyko 
Reviewed-by: Ryusuke Konishi 
Cc: Wenliang Fan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/nilfs2: fix integer overflow in nilfs_ioctl_wrap_copy()

2014-01-24T00:37:00+00:00

The local variable 'pos' in nilfs_ioctl_wrap_copy function can overflow if
a large number was passed to argv->v_index from userspace and the sum of
argv->v_index and argv->v_nmembs exceeds the maximum value of __u64 type
integer (= ~(__u64)0 = 18446744073709551615).

Here, argv->v_index is a 64-bit width argument to specify the start
position of target data items (such as segment number, checkpoint number,
or virtual block address of nilfs), and argv->v_nmembs gives the total
number of the items that userland programs (such as lssu, lscp, or
cleanerd) want to get information about, which also gives the maximum
element count of argv->v_base[] array.

nilfs_ioctl_wrap_copy() calls dofunc() repeatedly and increments the
position variable 'pos' at the end of each iteration if dofunc() itself
didn't update 'pos':

      if (pos == ppos)
              pos += n;

This patch prevents the overflow here by rejecting pairs of a start
position (argv->v_index) and a total count (argv->v_nmembs) which leads to
the overflow.

[konishi.ryusuke@lab.ntt.co.jp: fix signedness issue]
Signed-off-by: Wenliang Fan 
Cc: Vyacheslav Dubeyko 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds