Commit 9190cc0c authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

smb: client: improve purging of cached referrals 



Purge cached referrals that have a single target when reaching maximum
of cache size as the client won't need them to failover.  Otherwise
remove oldest cache entry.

Signed-off-by: default avatarPaulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 242d23ef

fs/smb/client/dfs_cache.c

+15 −17
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ static inline void free_tgts(struct cache_entry *ce) 


static inline void flush_cache_ent(struct cache_entry *ce)

{

	cifs_dbg(FYI, "%s: %s\n", __func__, ce->path);

	hlist_del_init(&ce->hlist);

	kfree(ce->path);

	free_tgts(ce);
@@ -441,34 +442,31 @@ static struct cache_entry *alloc_cache_entry(struct dfs_info3_param *refs, int n 
	return ce;

}



static void remove_oldest_entry_locked(void)

/* Remove all referrals that have a single target or oldest entry */

static void purge_cache(void)

{

	int i;

	struct cache_entry *ce;

	struct cache_entry *to_del = NULL;



	WARN_ON(!rwsem_is_locked(&htable_rw_lock));

	struct cache_entry *oldest = NULL;



	for (i = 0; i < CACHE_HTABLE_SIZE; i++) {

		struct hlist_head *l = &cache_htable[i];

		struct hlist_node *n;



		hlist_for_each_entry(ce, l, hlist) {

		hlist_for_each_entry_safe(ce, n, l, hlist) {

			if (hlist_unhashed(&ce->hlist))

				continue;

			if (!to_del || timespec64_compare(&ce->etime,

							  &to_del->etime) < 0)

				to_del = ce;

		}

			if (ce->numtgts == 1)

				flush_cache_ent(ce);

			else if (!oldest ||

				 timespec64_compare(&ce->etime,

						    &oldest->etime) < 0)

				oldest = ce;

		}



	if (!to_del) {

		cifs_dbg(FYI, "%s: no entry to remove\n", __func__);

		return;

	}



	cifs_dbg(FYI, "%s: removing entry\n", __func__);

	dump_ce(to_del);

	flush_cache_ent(to_del);

	if (atomic_read(&cache_count) >= CACHE_MAX_ENTRIES && oldest)

		flush_cache_ent(oldest);

}



/* Add a new DFS cache entry */
@@ -484,7 +482,7 @@ static struct cache_entry *add_cache_entry_locked(struct dfs_info3_param *refs, 


	if (atomic_read(&cache_count) >= CACHE_MAX_ENTRIES) {

		cifs_dbg(FYI, "%s: reached max cache size (%d)\n", __func__, CACHE_MAX_ENTRIES);

		remove_oldest_entry_locked();

		purge_cache();

	}



	rc = cache_entry_hash(refs[0].path_name, strlen(refs[0].path_name), &hash);