224 bytes are enough to store the target name

Signed-off-by: Christophe Vu-Brugier <cvubrugier@yahoo.fr>
Improve description of the configfs file hierarchy

Signed-off-by: Christophe Vu-Brugier <cvubrugier@yahoo.fr>
Clear the source attribute after the last target is deregistered

This patch fixes the following issue observed with the Microsoft iSNS
server: a target may not be registered.
This happens after a first target is created / deleted and then
another target is created. Here is a scenario with targetcli:

  /iscsi create iqn.2003-01.org.foo
  /iscsi delete iqn.2003-01.org.foo
  /iscsi create iqn.2003-01.org.bar

Signed-off-by: Christophe Vu-Brugier <cvubrugier@yahoo.fr>
Fix the allocation of epoll events

Valgrind reports that some data are uninitialized:

  1 errors in context 1 of 4:
  Syscall param epoll_ctl(event) points to uninitialised byte(s)
     at 0x4F17FBA: epoll_ctl (syscall-template.S:81)
     by 0x4067C4: epoll_add_fd (target-isns.c:71)
     by 0x406ABF: main (target-isns.c:180)
   Address 0xffeffff48 is on thread 1's stack
   Uninitialised value was created by a stack allocation
     at 0x40671F: epoll_add_fd (target-isns.c:52)

The epoll_event structure that valgrind reports as not being fully
initialized is allocated on the stack. This is wrong because the
structure can be accessed by epoll after the function returns. It is
safer to declare a static array of epoll_event structures.

Signed-off-by: Christophe Vu-Brugier <cvubrugier@yahoo.fr>