lkml.org 
[lkml]   [2021]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.12 030/700] gfs2: Fix underflow in gfs2_page_mkwrite
    Date
    From: Andreas Gruenbacher <agruenba@redhat.com>

    commit d3c51c55cb9274dd43c156f1f26b5eb4d5f2d58c upstream.

    On filesystems with a block size smaller than PAGE_SIZE and non-empty
    files smaller then PAGE_SIZE, gfs2_page_mkwrite could end up allocating
    excess blocks beyond the end of the file, similar to fallocate. This
    doesn't make sense; fix it.

    Reported-by: Bob Peterson <rpeterso@redhat.com>
    Fixes: 184b4e60853d ("gfs2: Fix end-of-file handling in gfs2_page_mkwrite")
    Cc: stable@vger.kernel.org # v5.5+
    Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/gfs2/file.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/fs/gfs2/file.c
    +++ b/fs/gfs2/file.c
    @@ -474,8 +474,8 @@ static vm_fault_t gfs2_page_mkwrite(stru
    file_update_time(vmf->vma->vm_file);

    /* page is wholly or partially inside EOF */
    - if (offset > size - PAGE_SIZE)
    - length = offset_in_page(size);
    + if (size - offset < PAGE_SIZE)
    + length = size - offset;
    else
    length = PAGE_SIZE;


    \
     
     \ /
      Last update: 2021-07-12 09:21    [W:2.437 / U:0.644 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site