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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: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Steve French 2023-08-30 22:48:41 -05:00
parent efc0b0bcff
commit 238b351d09
3 changed files with 13 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/smb/client/cached_dir.c
View File

@ -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--;

10
fs/smb/client/cifsfs.c
View File

@ -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;

1
fs/smb/client/cifsglob.h
View File

@ -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;