cifs: add new field to track the last access time of cfid

The handlecache code today tracks the time at which dir lease was
acquired and the laundromat thread uses that to check for old
entries to cleanup.

However, if a directory is actively accessed, it should not
be chosen to expire first.

This change adds a new last_access_time field to cfid and
uses that to decide expiry of the cfid.

Signed-off-by: Shyam Prasad N <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: sprasad-microsoft

fs/smb/client/cached_dir.c

@@ -195,6 +195,7 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 	 * from @cfids->entries.  Caller will put last reference if the latter.
 	 */
 	if (cfid->has_lease && cfid->time) {
+		cfid->last_access_time = jiffies;
 		spin_unlock(&cfids->cfid_list_lock);
 		*ret_cfid = cfid;
 		kfree(utf16_path);
@@ -363,6 +364,7 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 		cfid->file_all_info_is_valid = true;
 
 	cfid->time = jiffies;
+	cfid->last_access_time = jiffies;
 	spin_unlock(&cfids->cfid_list_lock);
 	/* At this point the directory handle is fully cached */
 	rc = 0;
@@ -730,8 +732,8 @@ static void cfids_laundromat_worker(struct work_struct *work)
 
 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
-		if (cfid->time &&
-		    time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) {
+		if (cfid->last_access_time &&
+		    time_after(jiffies, cfid->last_access_time + HZ * dir_cache_timeout)) {
 			cfid->on_list = false;
 			list_move(&cfid->entry, &entry);
 			cfids->num_entries--;

fs/smb/client/cached_dir.h

@@ -39,6 +39,7 @@ struct cached_fid {
 	bool on_list:1;
 	bool file_all_info_is_valid:1;
 	unsigned long time; /* jiffies of when lease was taken */
+	unsigned long last_access_time; /* jiffies of when last accessed */
 	struct kref refcount;
 	struct cifs_fid fid;
 	spinlock_t fid_lock;