debian: fix start of ceph-all

Tolerate failure, and do ceph-all, not ceph-osd-all.

Signed-off-by: Sage Weil <sage@inktank.com>
ceph-disk-prepare: -f for mkfs.xfs only

Signed-off-by: Sage Weil <sage@inktank.com>
buffer::ptr::cmp only compares up to the smallest length

When running

  bufferptr a("A", 1);
  bufferptr ab("AB", 2);
  a.cmp(ab);

it returned zero because. cmp only compared up to the length of the
smallest buffer and returned if they are identical. The function is
modified to compare the length of the buffers instead of returning.

http://tracker.ceph.com/issues/4170 refs #4170

Signed-off-by: Loic Dachary <loic@dachary.org>
unit tests for src/common/buffer.{cc,h}

Implement unit tests covering most lines of code ( > 92% ) and all
methods as show by the output of make check-coverage :
http://dachary.org/wp-uploads/2013/03/ceph-lcov/ .

The following static constructors are implemented by opaque classes
defined in buffer.cc ( buffer::raw_char, buffer::raw_posix_aligned
etc. ). Testing the implementation of these classes is done by
variations of the calls to the static constructors.

    copy(const char *c, unsigned len);
    create(unsigned len);
    claim_char(unsigned len, char *buf);
    create_malloc(unsigned len);
    claim_malloc(unsigned len, char *buf);
    create_static(unsigned len, char *buf);
    create_page_aligned(unsigned len);

The raw_mmap_pages class cannot be tested because it is commented out in
raw_posix_aligned. The raw_hack_aligned class is only tested under Cygwin.
The raw_posix_aligned class is not tested under Cygwin.

The unittest_bufferlist.sh script calls unittest_bufferlist with the
CEPH_BUFFER_TRACK=true environment variable to enable the code
tracking the memory usage. It cannot be done within the bufferlist.cc
file itself because it relies on the initialization of a global
variable  ( buffer_track_alloc ).

When raw_posix_aligned is called on DARWIN, the data is not aligned
on CEPH_PAGE_SIZE because it calls valloc(size) which is the equivalent of
memalign(sysconf(_SC_PAGESIZE),size) and not memalign(CEPH_PAGE_SIZE,size).
For this reason the alignment test is de-activated on DARWIN.

The tests are grouped in

TEST(BufferPtr, ... ) for buffer::ptr
TEST(BufferListIterator, ...) for buffer::list::iterator
TEST(BufferList, ...) for buffer::list
TEST(BufferHash, ...) for buffer::hash

and each method ( and all variations of the prototype ) are
included into a single TEST() function.

Although most aspects of the methods are tested, including exceptions
and border cases, inconsistencies are not highlighted . For
instance

    buffer::list::iterator i;
    i.advance(1);

would dereference a buffer::raw NULL pointer although

    buffer::ptr p;
    p.wasted()

asserts instead of dereferencing the buffer::raw NULL pointer. It
would be better to always assert in case a NULL pointer is about to be
used. But this is a minor inconsistency that is probably not worth a
test.

The following buffer::list methods

    ssize_t read_fd(int fd, size_t len);
    int write_fd(int fd) const;

are not fully tested because the border cases cannot be reliably
reproduced. Going thru a pointer indirection when calling the ::writev
or safe_read functions would allow the test to create mockups to synthetize
the conditions for border cases.

tracker.ceph.com/issues/4066 refs #4066

Signed-off-by: Loic Dachary <loic@dachary.org>