struct zvol_state contains a dummy znode, which is around 1KB on x64,
only for zfs_range_lock. But in reality, other than z_range_lock and
z_range_avl, zfs_range_lock only need znode on regular file, which
means we add 1KB on a structure and gain nothing.
In this patch, we remove the dummy znode for zvol_state. In order to
do that, we also need to refactor zfs_range_lock a bit. We move
z_range_lock and z_range_avl pair out of znode_t to form zfs_rlock_t.
This new struct replaces znode_t as the main handle inside the range
lock functions.
We also add pointers to z_size, z_blksz, and z_max_blksz so range lock
code doesn't depend on znode_t. This allows non-ZPL consumers like
Lustre to use the range locks with their equivalent znode_t structure.
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4510
Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate
typedef declarations with the same type. The trace.h header contains
some typedefs to avoid 'unknown type' errors for C files that haven't
declared the type in question. But this causes build failures for C
files that have already declared the type. Newer versions of GCC (e.g.
v4.6) allow duplicate typedefs with the same type unless pedantic error
checking is in force. To support the older versions we need to remove
the duplicate typedefs.
Removal of the typedefs means we can't built tracepoints code using
those types unless the required headers have been included. To
facilitate this, all tracepoint event declarations have been moved out
of trace.h into separate headers. Each new header is explicitly included
from the C file that uses the events defined therein. The trace.h header
is still indirectly included form zfs_context.h and provides the
implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces.
This makes those interfaces readily available throughout the code base.
The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also
still provided by trace.h, so it is a prerequisite for the other
trace_*.h headers.
These new Linux implementation-specific headers do introduce a small
divergence from upstream ZFS in several core C files, but this should
not present a significant maintenance burden.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2953
Chunwei Chen
Frédéric VANNIÈRE
Ned Bass