Commit dde6667f authored by Bharath SM's avatar Bharath SM Committed by Steve French
Browse files

smb: client: add drop_dir_cache module parameter to invalidate cached dirents 



Add write-only /sys/module/cifs/parameters/drop_dir_cache. Writing a
non-zero value iterates all tcons and calls invalidate_all_cached_dirs()
to drop cached directory entries. This is useful to force a dirent cache
drop across mounts for debugging and testing purpose.

Signed-off-by: default avatarBharath SM <bharathsm@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent ac3ad984

fs/smb/client/cifsfs.c

+38 −0
Original line number Diff line number Diff line
@@ -121,6 +121,44 @@ unsigned int dir_cache_timeout = 30; 
module_param(dir_cache_timeout, uint, 0644);

MODULE_PARM_DESC(dir_cache_timeout, "Number of seconds to cache directory contents for which we have a lease. Default: 30 "

				 "Range: 1 to 65000 seconds, 0 to disable caching dir contents");



/*

 * Write-only module parameter to drop all cached directory entries across

 * all CIFS mounts. Echo a non-zero value to trigger.

 */

static void cifs_drop_all_dir_caches(void)

{

	struct TCP_Server_Info *server;

	struct cifs_ses *ses;

	struct cifs_tcon *tcon;



	spin_lock(&cifs_tcp_ses_lock);

	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {

		list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {

			if (cifs_ses_exiting(ses))

				continue;

			list_for_each_entry(tcon, &ses->tcon_list, tcon_list)

				invalidate_all_cached_dirs(tcon);

		}

	}

	spin_unlock(&cifs_tcp_ses_lock);

}



static int cifs_param_set_drop_dir_cache(const char *val, const struct kernel_param *kp)

{

	bool bv;

	int rc = kstrtobool(val, &bv);



	if (rc)

		return rc;

	if (bv)

		cifs_drop_all_dir_caches();

	return 0;

}



module_param_call(drop_dir_cache, cifs_param_set_drop_dir_cache, NULL, NULL, 0200);

MODULE_PARM_DESC(drop_dir_cache, "Write 1 to drop all cached directory entries across all CIFS mounts");



#ifdef CONFIG_CIFS_STATS2

unsigned int slow_rsp_threshold = 1;

module_param(slow_rsp_threshold, uint, 0644);