• Ashish Samant's avatar
    ocfs2: fix start offset to ocfs2_zero_range_for_truncate() · d21c353d
    Ashish Samant authored
    If we punch a hole on a reflink such that following conditions are met:
    
    1. start offset is on a cluster boundary
    2. end offset is not on a cluster boundary
    3. (end offset is somewhere in another extent) or
       (hole range > MAX_CONTIG_BYTES(1MB)),
    
    we dont COW the first cluster starting at the start offset.  But in this
    case, we were wrongly passing this cluster to
    ocfs2_zero_range_for_truncate() to zero out.  This will modify the
    cluster in place and zero it in the source too.
    
    Fix this by skipping this cluster in such a scenario.
    
    To reproduce:
    
    1. Create a random file of say 10 MB
         xfs_io -c 'pwrite -b 4k 0 10M' -f 10MBfile
    2. Reflink  it
         reflink -f 10MBfile reflnktest
    3. Punch a hole at starting at cluster boundary  with range greater that
    1MB. You can also use a range that will put the end offset in another
    extent.
         fallocate -p -o 0 -l 1048615 reflnktest
    4. sync
    5. Check the  first cluster in the source file. (It will be zeroed out).
        dd if=10MBfile iflag=direct bs=<cluster size> count=1 | hexdump -C
    
    Link: http://lkml.kernel.org/r/1470957147-14185-1-git-send-email-ashish.samant@oracle.comSigned-off-by: default avatarAshish Samant <ashish.samant@oracle.com>
    Reported-by: default avatarSaar Maoz <saar.maoz@oracle.com>
    Reviewed-by: default avatarSrinivas Eeda <srinivas.eeda@oracle.com>
    Cc: Mark Fasheh <mfasheh@suse.de>
    Cc: Joel Becker <jlbec@evilplan.org>
    Cc: Junxiao Bi <junxiao.bi@oracle.com>
    Cc: Joseph Qi <joseph.qi@huawei.com>
    Cc: Eric Ren <zren@suse.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    d21c353d
file.c 62.3 KB