afs: Overhaul cell database management
Overhaul the way that the in-kernel AFS client keeps track of cells in the
following manner:
(1) Cells are now held in an rbtree to make walking them quicker and RCU
managed (though this is probably overkill).
(2) Cells now have a manager work item that:
(A) Looks after fetching and refreshing the VL server list.
(B) Manages cell record lifetime, including initialising and
destruction.
(B) Manages cell record caching whereby threads are kept around for a
certain time after last use and then destroyed.
(C) Manages the FS-Cache index cookie for a cell. It is not permitted
for a cookie to be in use twice, so we have to be careful to not
allow a new cell record to exist at the same time as an old record
of the same name.
(3) Each AFS network namespace is given a manager work item that manages
the cells within it, maintaining a single timer to prod cells into
updating their DNS records.
This uses the reduce_timer() facility to make the timer expire at the
soonest timed event that needs happening.
(4) When a module is being unloaded, cells and cell managers are now
counted out using dec_after_work() to make sure the module text is
pinned until after the data structures have been cleaned up.
(5) Each cell's VL server list is now protected by a seqlock rather than a
semaphore.
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/afs/super.c b/fs/afs/super.c
index e62fb1b..3d53b78 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -200,10 +200,11 @@ static int afs_parse_options(struct afs_mount_params *params,
token = match_token(p, afs_options_list, args);
switch (token) {
case afs_opt_cell:
- cell = afs_cell_lookup(params->net,
- args[0].from,
- args[0].to - args[0].from,
- false);
+ rcu_read_lock();
+ cell = afs_lookup_cell_rcu(params->net,
+ args[0].from,
+ args[0].to - args[0].from);
+ rcu_read_unlock();
if (IS_ERR(cell))
return PTR_ERR(cell);
afs_put_cell(params->net, params->cell);
@@ -308,7 +309,8 @@ static int afs_parse_device_name(struct afs_mount_params *params,
/* lookup the cell record */
if (cellname || !params->cell) {
- cell = afs_cell_lookup(params->net, cellname, cellnamesz, true);
+ cell = afs_lookup_cell(params->net, cellname, cellnamesz,
+ NULL, false);
if (IS_ERR(cell)) {
printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
cellnamesz, cellnamesz, cellname ?: "");