1. 09 Feb, 2017 37 commits
  2. 04 Feb, 2017 3 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.9.8 · c8ea2f3b
      Greg Kroah-Hartman authored
      c8ea2f3b
    • Darrick J. Wong's avatar
      xfs: fix bmv_count confusion w/ shared extents · b5b4d4a9
      Darrick J. Wong authored
      commit c364b6d0 upstream.
      
      In a bmapx call, bmv_count is the total size of the array, including the
      zeroth element that userspace uses to supply the search key.  The output
      array starts at offset 1 so that we can set up the user for the next
      invocation.  Since we now can split an extent into multiple bmap records
      due to shared/unshared status, we have to be careful that we don't
      overflow the output array.
      
      In the original patch f86f4037 ("xfs: teach get_bmapx about shared
      extents and the CoW fork") I used cur_ext (the output index) to check
      for overflows, albeit with an off-by-one error.  Since nexleft no longer
      describes the number of unfilled slots in the output, we can rip all
      that out and use cur_ext for the overflow check directly.
      
      Failure to do this causes heap corruption in bmapx callers such as
      xfs_io and xfs_scrub.  xfs/328 can reproduce this problem.
      Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b5b4d4a9
    • Darrick J. Wong's avatar
      xfs: clear _XBF_PAGES from buffers when readahead page · 5d44dd54
      Darrick J. Wong authored
      commit 2aa6ba7b upstream.
      
      If we try to allocate memory pages to back an xfs_buf that we're trying
      to read, it's possible that we'll be so short on memory that the page
      allocation fails.  For a blocking read we'll just wait, but for
      readahead we simply dump all the pages we've collected so far.
      
      Unfortunately, after dumping the pages we neglect to clear the
      _XBF_PAGES state, which means that the subsequent call to xfs_buf_free
      thinks that b_pages still points to pages we own.  It then double-frees
      the b_pages pages.
      
      This results in screaming about negative page refcounts from the memory
      manager, which xfs oughtn't be triggering.  To reproduce this case,
      mount a filesystem where the size of the inodes far outweighs the
      availalble memory (a ~500M inode filesystem on a VM with 300MB memory
      did the trick here) and run bulkstat in parallel with other memory
      eating processes to put a huge load on the system.  The "check summary"
      phase of xfs_scrub also works for this purpose.
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      5d44dd54