[Ocfs2-devel] [PATCH] ocfs2: Cache some system inodes of other nodes.
Sunil Mushran
sunil.mushran at oracle.com
Thu Aug 12 18:03:51 PDT 2010
On 08/12/2010 02:43 AM, Joel Becker wrote:
> On Thu, Aug 12, 2010 at 05:03:16PM +0800, Tao Ma wrote:
>> In ocfs2, we now only cache the inodes for global system file
>> and the system inodes for our own slot. But we have some cases
>> that we may need to access system inodes of other nodes, such
>> as orphan scan, inode steal etc.
>
> I don't see why you don't extend the existing cache and make one
> cache. Make it live the lifetime of the filesystem. No real reason to
> a) have to caches or b) limit the system inodes we might cache. If we
> don't have the lock we're going to re-read them anyway.
Yeah... I have to agree. Will make it more readable.
enum {
BAD_BLOCK_SYSTEM_INODE = 0,
GLOBAL_INODE_ALLOC_SYSTEM_INODE,
SLOT_MAP_SYSTEM_INODE,
#define OCFS2_FIRST_ONLINE_SYSTEM_INODE SLOT_MAP_SYSTEM_INODE
HEARTBEAT_SYSTEM_INODE,
GLOBAL_BITMAP_SYSTEM_INODE,
USER_QUOTA_SYSTEM_INODE,
GROUP_QUOTA_SYSTEM_INODE,
#define OCFS2_LAST_GLOBAL_SYSTEM_INODE GROUP_QUOTA_SYSTEM_INODE
#define OCFS2_FIRST_LOCAL_SYSTEM_INODE ORPHAN_DIR_SYSTEM_INODE
ORPHAN_DIR_SYSTEM_INODE,
EXTENT_ALLOC_SYSTEM_INODE,
INODE_ALLOC_SYSTEM_INODE,
JOURNAL_SYSTEM_INODE,
LOCAL_ALLOC_SYSTEM_INODE,
TRUNCATE_LOG_SYSTEM_INODE,
LOCAL_USER_QUOTA_SYSTEM_INODE,
LOCAL_GROUP_QUOTA_SYSTEM_INODE,
NUM_SYSTEM_INODES
};
#define NUM_LOCAL_SYSTEM_INODES (NUM_SYSTEM_INODES -
OCFS2_FIRST_LOCAL_SYSTEM_INODE)
struct ocfs2_super {
...
struct inode *global_system_inodes[OCFS2_LAST_GLOBAL_SYSTEM_INODE];
struct inode **local_system_inodes;
...
};
local_system_inodes = kzalloc(sizeof(struct inode *) * osb->num_slots *
NUM_LOCAL_SYSTEM_INODES;
/* avoid the lookup if cached in local system file array */
if (is_in_system_inode_array(osb, type, slot))
arr = &(osb->system_inodes[type]);
change to:
if (is_global_system_inode(type)
arr = &(osb->global_system_inodes[type]);
else {
BUG_ON(slot == OCFS2_INVALID_SLOT);
BUG_ON(type < OCFS2_FIRST_LOCAL_SYSTEM_INODE ||
type > LOCAL_GROUP_QUOTA_SYSTEM_INODE);
tmp = (slot * NUM_LOCAL_SYSTEM_INODES) +
(type - OCFS2_FIRST_LOCAL_SYSTEM_INODE);
arr = &(osb->local_system_inodes[tmp];
}
How does this look?
The only downside is that the kzmalloc for more than 64 slots will
require more than a page on 64-bit systems. But that should be ok.
Sunil
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