zfs/tests/zfs-tests
Brian Behlendorf 751941e248 Fix dnode allocation race
When performing concurrent object allocations using the new
multi-threaded allocator and large dnodes it's possible to
allocate overlapping large dnodes.

This case should have been handled by detecting an error
returned by dnode_hold_impl().  But that logic only checked
the returned dnp was not-NULL, and the dnp variable was not
reset to NULL when retrying.  Resolve this issue by properly
checking the return value of dnode_hold_impl().

Additionally, it was possible that dnode_hold_impl() would
misreport a dnode as free when it was in fact in use.  This
could occurs for two reasons:

* The per-slot zrl_lock must be held over the entire critical
  section which includes the alloc/free until the new dnode
  is assigned to children_dnodes.  Additionally, all of the
  zrl_lock's in the range must be held to protect moving
  dnodes.

* The dn->dn_ot_type cannot be solely relied upon to check
  the type.  When allocating a new dnode its type will be
  DMU_OT_NONE after dnode_create().  Only latter when
  dnode_allocate() is called will it transition to the new
  type.  This means there's a window when allocating where
  it can mistaken for a free dnode.

Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Ned Bass <bass6@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6414
Closes #6439
2017-08-08 10:17:33 -07:00
..
callbacks Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
cmd Enable remaining tests 2017-05-22 12:34:32 -04:00
include Fix volmode=none property behavior at import time 2017-08-02 11:21:14 -07:00
tests Fix dnode allocation race 2017-08-08 10:17:33 -07:00
Makefile.am OpenZFS 7503 - zfs-test should tail ::zfs_dbgmsg on test failure 2017-04-12 13:36:48 -07:00