Commit 238b351d authored by Steve French's avatar Steve French
Browse files

smb3: allow controlling length of time directory entries are cached with dir leases 



Currently with directory leases we cache directory contents for a fixed period
of time (default 30 seconds) but for many workloads this is too short.  Allow
configuring the maximum amount of time directory entries are cached when a
directory lease is held on that directory. Add module load parm "max_dir_cache"

For example to set the timeout to 10 minutes you would do:

  echo 600 > /sys/module/cifs/parameters/dir_cache_timeout

or to disable caching directory contents:

  echo 0 > /sys/module/cifs/parameters/dir_cache_timeout

Reviewed-by: default avatarBharath SM <bharathsm@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent efc0b0bc

fs/smb/client/cached_dir.c

+2 −2
Original line number Diff line number Diff line
@@ -145,7 +145,7 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
	const char *npath;



	if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache ||

	    is_smb1_server(tcon->ses->server))

	    is_smb1_server(tcon->ses->server) || (dir_cache_timeout == 0))

		return -EOPNOTSUPP;



	ses = tcon->ses;
@@ -582,7 +582,7 @@ cifs_cfids_laundromat_thread(void *p) 
			return 0;

		spin_lock(&cfids->cfid_list_lock);

		list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {

			if (time_after(jiffies, cfid->time + HZ * 30)) {

			if (time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) {

				list_del(&cfid->entry);

				list_add(&cfid->entry, &entry);

				cfids->num_entries--;

fs/smb/client/cifsfs.c

+10 −0
Original line number Diff line number Diff line
@@ -117,6 +117,10 @@ module_param(cifs_max_pending, uint, 0444); 
MODULE_PARM_DESC(cifs_max_pending, "Simultaneous requests to server for "

				   "CIFS/SMB1 dialect (N/A for SMB3) "

				   "Default: 32767 Range: 2 to 32767.");

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");

#ifdef CONFIG_CIFS_STATS2

unsigned int slow_rsp_threshold = 1;

module_param(slow_rsp_threshold, uint, 0644);
@@ -1679,6 +1683,12 @@ init_cifs(void) 
			 CIFS_MAX_REQ);

	}



	/* Limit max to about 18 hours, and setting to zero disables directory entry caching */

	if (dir_cache_timeout > 65000) {

		dir_cache_timeout = 65000;

		cifs_dbg(VFS, "dir_cache_timeout set to max of 65000 seconds\n");

	}



	cifsiod_wq = alloc_workqueue("cifsiod", WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);

	if (!cifsiod_wq) {

		rc = -ENOMEM;

fs/smb/client/cifsglob.h

+1 −0
Original line number Diff line number Diff line
@@ -2016,6 +2016,7 @@ extern unsigned int CIFSMaxBufSize; /* max size not including hdr */ 
extern unsigned int cifs_min_rcv;    /* min size of big ntwrk buf pool */

extern unsigned int cifs_min_small;  /* min size of small buf pool */

extern unsigned int cifs_max_pending; /* MAX requests at once to server*/

extern unsigned int dir_cache_timeout; /* max time for directory lease caching of dir */

extern bool disable_legacy_dialects;  /* forbid vers=1.0 and vers=2.0 mounts */

extern atomic_t mid_count;