• Jie Liu's avatar
    ocfs2: fix the end cluster offset of FIEMAP · 28e8be31
    Jie Liu authored
    Call fiemap ioctl(2) with given start offset as well as an desired mapping
    range should show extents if possible.  However, we somehow figure out the
    end offset of mapping via 'mapping_end -= cpos' before iterating the
    extent records which would cause problems if the given fiemap length is
    too small to a cluster size, e.g,
    Cluster size 4096:
    debugfs.ocfs2 1.6.3
            Block Size Bits: 12   Cluster Size Bits: 12
    The extended fiemap test utility From David:
    # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
    # ./fiemap /ocfs2/test_file 4096 10
    start: 4096, length: 10
    File /ocfs2/test_file has 0 extents:
    #	Logical          Physical         Length           Flags
    	^^^^^ <-- No extent is shown
    In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
    loop of searching extent records was not executed at all.
    This patch remove the in question 'mapping_end -= cpos', and loops
    until the cpos is larger than the mapping_end as usual.
    # ./fiemap /ocfs2/test_file 4096 10
    start: 4096, length: 10
    File /ocfs2/test_file has 1 extents:
    #	Logical          Physical         Length           Flags
    0:	0000000000000000 0000000056a01000 0000000006a00000 0000
    Signed-off-by: default avatarJie Liu <jeff.liu@oracle.com>
    Reported-by: default avatarDavid Weber <wb@munzinger.de>
    Tested-by: default avatarDavid Weber <wb@munzinger.de>
    Cc: Sunil Mushran <sunil.mushran@gmail.com>
    Cc: Mark Fashen <mfasheh@suse.de>
    Cc: Joel Becker <jlbec@evilplan.org>
    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>
extent_map.c 23.2 KB