• Yan, Zheng's avatar
    ceph: track read contexts in ceph_file_info · 5d988308
    Yan, Zheng authored
    Previously ceph_read_iter() uses current->journal to pass context info
    to ceph_readpages(), so that ceph_readpages() can distinguish read(2)
    from readahead(2)/fadvise(2)/madvise(2). The problem is that page fault
    can happen when copying data to userspace memory. Page fault may call
    other filesystem's page_mkwrite() if the userspace memory is mapped to a
    file. The later filesystem may also want to use current->journal.
    
    The fix is define a on-stack data structure in ceph_read_iter(), add it
    to context list in ceph_file_info. ceph_readpages() searches the list,
    find if there is a context belongs to current thread.
    Signed-off-by: default avatar"Yan, Zheng" <zyan@redhat.com>
    Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
    5d988308
file.c 43.5 KB