From: Paulo Alcantara <pc@cjr.nz>

Date: Tue, 13 Dec 2022 00:29:22 -0300

Subject: [PATCH] cifs: don't refresh cached referrals from unactive mounts

Git-commit: cb3f6d8764529c33269c3478c17641cb097a615b

References: bsc#1193629

Patch-mainline: v6.2-rc1

There is no point refreshing cached referrals from unactive mounts as

they will no longer be used and new mounts will either create or

refresh them anyway.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>

Signed-off-by: Steve French <stfrench@microsoft.com>

Acked-by: Paulo Alcantara <palcantara@suse.de>

---

 fs/cifs/dfs_cache.c | 73 +--------------------------------------------

 1 file changed, 1 insertion(+), 72 deletions(-)

diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c

index bf5e674f43b8..bef672534397 100644

--- a/fs/cifs/dfs_cache.c

+++ b/fs/cifs/dfs_cache.c

@@ -1549,74 +1549,6 @@ static void refresh_mounts(struct cifs_ses **sessions)

 	}

 }

-static void refresh_cache(struct cifs_ses **sessions)

-{

-	int i;

-	struct cifs_ses *ses;

-	unsigned int xid;

-	char *ref_paths[CACHE_MAX_ENTRIES];

-	int count = 0;

-	struct cache_entry *ce;

-

-	/*

-	 * Refresh all cached entries.  Get all new referrals outside critical section to avoid

-	 * starvation while performing SMB2 IOCTL on broken or slow connections.

-

-	 * The cache entries may cover more paths than the active mounts

-	 * (e.g. domain-based DFS referrals or multi tier DFS setups).

-	 */

-	down_read(&htable_rw_lock);

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

-		struct hlist_head *l = &cache_htable[i];

-

-		hlist_for_each_entry(ce, l, hlist) {

-			if (count == ARRAY_SIZE(ref_paths))

-				goto out_unlock;

-			if (hlist_unhashed(&ce->hlist) || !cache_entry_expired(ce) ||

-			    IS_ERR(find_ipc_from_server_path(sessions, ce->path)))

-				continue;

-			ref_paths[count++] = kstrdup(ce->path, GFP_ATOMIC);

-		}

-	}

-

-out_unlock:

-	up_read(&htable_rw_lock);

-

-	for (i = 0; i < count; i++) {

-		char *path = ref_paths[i];

-		struct dfs_info3_param *refs = NULL;

-		int numrefs = 0;

-		int rc = 0;

-

-		if (!path)

-			continue;

-

-		ses = find_ipc_from_server_path(sessions, path);

-		if (IS_ERR(ses))

-			goto next_referral;

-

-		xid = get_xid();

-		rc = get_dfs_referral(xid, ses, path, &refs, &numrefs);

-		free_xid(xid);

-

-		if (!rc) {

-			down_write(&htable_rw_lock);

-			ce = lookup_cache_entry(path);

-			/*

-			 * We need to re-check it because other tasks might have it deleted or

-			 * updated.

-			 */

-			if (!IS_ERR(ce) && cache_entry_expired(ce))

-				update_cache_entry_locked(ce, refs, numrefs);

-			up_write(&htable_rw_lock);

-		}

-

-next_referral:

-		kfree(path);

-		free_dfs_info_array(refs, numrefs);

-	}

-}

-

 /*

  * Worker that will refresh DFS cache and active mounts based on lowest TTL value from a DFS

  * referral.

@@ -1654,11 +1586,8 @@ static void refresh_cache_worker(struct work_struct *work)

 		i += count;

 	}

-	if (sessions[0]) {

-		/* Refresh all active mounts and cached entries */

+	if (sessions[0])

 		refresh_mounts(sessions);

-		refresh_cache(sessions);

-	}

 	list_for_each_entry_safe(mg, tmp_mg, &mglist, refresh_list) {

 		list_del_init(&mg->refresh_list);

-- 

2.39.0