don't remove from shrink list in select_collect()
authorAl Viro <viro@zeniv.linux.org.uk>
Sat, 3 May 2014 04:02:25 +0000 (00:02 -0400)
committerAl Viro <viro@zeniv.linux.org.uk>
Sat, 3 May 2014 20:45:06 +0000 (16:45 -0400)
If we find something already on a shrink list, just increment
data->found and do nothing else.  Loops in shrink_dcache_parent() and
check_submounts_and_drop() will do the right thing - everything we
did put into our list will be evicted and if there had been nothing,
but data->found got non-zero, well, we have somebody else shrinking
those guys; just try again.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/dcache.c

index 58e26be..f39a6f5 100644 (file)
@@ -1229,34 +1229,23 @@ static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
        if (data->start == dentry)
                goto out;
 
-       /*
-        * move only zero ref count dentries to the dispose list.
-        *
-        * Those which are presently on the shrink list, being processed
-        * by shrink_dentry_list(), shouldn't be moved.  Otherwise the
-        * loop in shrink_dcache_parent() might not make any progress
-        * and loop forever.
-        */
-       if (dentry->d_lockref.count) {
-               dentry_lru_del(dentry);
-       } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) {
-               /*
-                * We can't use d_lru_shrink_move() because we
-                * need to get the global LRU lock and do the
-                * LRU accounting.
-                */
-               d_lru_del(dentry);
-               d_shrink_add(dentry, &data->dispose);
+       if (dentry->d_flags & DCACHE_SHRINK_LIST) {
                data->found++;
-               ret = D_WALK_NORETRY;
+       } else {
+               if (dentry->d_flags & DCACHE_LRU_LIST)
+                       d_lru_del(dentry);
+               if (!dentry->d_lockref.count) {
+                       d_shrink_add(dentry, &data->dispose);
+                       data->found++;
+               }
        }
        /*
         * We can return to the caller if we have found some (this
         * ensures forward progress). We'll be coming back to find
         * the rest.
         */
-       if (data->found && need_resched())
-               ret = D_WALK_QUIT;
+       if (!list_empty(&data->dispose))
+               ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
 out:
        return ret;
 }