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authorDavid Howells <dhowells@redhat.com>2017-11-02 15:27:50 +0000
committerDavid Howells <dhowells@redhat.com>2017-11-13 15:38:18 +0000
commit989782dcdc91a5e6d5999c7a52a84a60a0811e56 (patch)
tree138ed46554536280e0d4d1834a16c28740e8cdae /fs/afs/proc.c
parentbe080a6f43c40976afc950ee55e9b7f8e2b53525 (diff)
downloadlinux-989782dcdc91a5e6d5999c7a52a84a60a0811e56.tar.bz2
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>
Diffstat (limited to 'fs/afs/proc.c')
-rw-r--r--fs/afs/proc.c15
1 files changed, 6 insertions, 9 deletions
diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index d00d550ff2ef..08565429615d 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -186,7 +186,7 @@ static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
{
struct afs_net *net = afs_seq2net(m);
- down_read(&net->proc_cells_sem);
+ rcu_read_lock();
return seq_list_start_head(&net->proc_cells, *_pos);
}
@@ -205,9 +205,7 @@ static void *afs_proc_cells_next(struct seq_file *m, void *v, loff_t *pos)
*/
static void afs_proc_cells_stop(struct seq_file *m, void *v)
{
- struct afs_net *net = afs_seq2net(m);
-
- up_read(&net->proc_cells_sem);
+ rcu_read_unlock();
}
/*
@@ -225,8 +223,7 @@ static int afs_proc_cells_show(struct seq_file *m, void *v)
}
/* display one cell per line on subsequent lines */
- seq_printf(m, "%3d %s\n",
- atomic_read(&cell->usage), cell->name);
+ seq_printf(m, "%3u %s\n", atomic_read(&cell->usage), cell->name);
return 0;
}
@@ -279,13 +276,13 @@ static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
if (strcmp(kbuf, "add") == 0) {
struct afs_cell *cell;
- cell = afs_cell_create(net, name, strlen(name), args, false);
+ cell = afs_lookup_cell(net, name, strlen(name), args, true);
if (IS_ERR(cell)) {
ret = PTR_ERR(cell);
goto done;
}
- afs_put_cell(net, cell);
+ set_bit(AFS_CELL_FL_NO_GC, &cell->flags);
printk("kAFS: Added new cell '%s'\n", name);
} else {
goto inval;
@@ -354,7 +351,7 @@ int afs_proc_cell_setup(struct afs_net *net, struct afs_cell *cell)
{
struct proc_dir_entry *dir;
- _enter("%p{%s}", cell, cell->name);
+ _enter("%p{%s},%p", cell, cell->name, net->proc_afs);
dir = proc_mkdir(cell->name, net->proc_afs);
if (!dir)