• J
    ext4: fix SEEK_HOLE/SEEK_DATA for blocksize < pagesize · fcf5ea10
    Jan Kara 提交于
    ext4_find_unwritten_pgoff() does not properly handle a situation when
    starting index is in the middle of a page and blocksize < pagesize. The
    following command shows the bug on filesystem with 1k blocksize:
    
      xfs_io -f -c "falloc 0 4k" \
                -c "pwrite 1k 1k" \
                -c "pwrite 3k 1k" \
                -c "seek -a -r 0" foo
    
    In this example, neither lseek(fd, 1024, SEEK_HOLE) nor lseek(fd, 2048,
    SEEK_DATA) will return the correct result.
    
    Fix the problem by neglecting buffers in a page before starting offset.
    Reported-by: NAndreas Gruenbacher <agruenba@redhat.com>
    Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
    Signed-off-by: NJan Kara <jack@suse.cz>
    CC: stable@vger.kernel.org # 3.8+
    fcf5ea10
file.c 18.7 KB