Remove dummy znode from zvol_state

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
This commit is contained in:
Chunwei Chen
2016-04-11 14:53:48 -07:00
committed by Brian Behlendorf
parent 61a3d06f84
commit d88895a069
8 changed files with 105 additions and 76 deletions
+2 -3
View File
@@ -37,6 +37,7 @@
#include <sys/rrwlock.h>
#include <sys/zfs_sa.h>
#include <sys/zfs_stat.h>
#include <sys/zfs_rlock.h>
#endif
#include <sys/zfs_acl.h>
#include <sys/zil.h>
@@ -187,8 +188,7 @@ typedef struct znode {
krwlock_t z_parent_lock; /* parent lock for directories */
krwlock_t z_name_lock; /* "master" lock for dirent locks */
zfs_dirlock_t *z_dirlocks; /* directory entry lock list */
kmutex_t z_range_lock; /* protects changes to z_range_avl */
avl_tree_t z_range_avl; /* avl tree of file range locks */
zfs_rlock_t z_range_lock; /* file range lock */
uint8_t z_unlinked; /* file has been unlinked */
uint8_t z_atime_dirty; /* atime needs to be synced */
uint8_t z_zn_prefetch; /* Prefetch znodes? */
@@ -212,7 +212,6 @@ typedef struct znode {
list_node_t z_link_node; /* all znodes in fs link */
sa_handle_t *z_sa_hdl; /* handle to sa data */
boolean_t z_is_sa; /* are we native sa? */
boolean_t z_is_zvol; /* are we used by the zvol */
boolean_t z_is_mapped; /* are we mmap'ed */
boolean_t z_is_ctldir; /* are we .zfs entry */
boolean_t z_is_stale; /* are we stale due to rollback? */