smb: client: add CFID_LOOKUP_PARENT lookup modifier

Add support for find_cached_dir() to lookup for a path's parent.

* will be used to set ParentLeaseKey on opens

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>

2 files changed, 27 insertions, 1 deletions

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index c4f110fc66d5..ad9c95c20c4e 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -134,10 +134,28 @@ static const char *path_no_prefix(struct cifs_sb_info *cifs_sb,
 struct cached_fid *find_cached_dir(struct cached_fids *cfids, const void *key, int mode)
 {
 	struct cached_fid *cfid;
+	char *parent_path = NULL;
 
 	if (!cfids || !key)
 		return NULL;
 
+	/* special case */
+	if (mode == CFID_LOOKUP_PARENT) {
+		const char *path = key;
+
+		if (!*path)
+			return NULL;
+
+		parent_path = strrchr(path, cfids->dirsep);
+		if (!parent_path)
+			return NULL;
+
+		parent_path = kstrndup(path, parent_path - path, GFP_ATOMIC);
+		if (!parent_path)
+			return NULL;
+
+		key = parent_path;
+	}
 retry_find:
 	cfid = find_cfid(cfids, key, mode);
 	if (cfid) {
@@ -159,6 +177,8 @@ retry_find:
 		}
 	}
 
+	kfree(parent_path);
+
 	return cfid;
 }
 
@@ -200,9 +220,11 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, const char *path,
 
 	ses = tcon->ses;
 	cfids = tcon->cfids;
-
 	if (!cfids)
 		return -EOPNOTSUPP;
+
+	if (!cfids->dirsep)
+		cfids->dirsep = CIFS_DIR_SEP(cifs_sb);
 replay_again:
 	/* reinitialize for possible replay */
 	flags = 0;
diff --git a/fs/smb/client/cached_dir.h b/fs/smb/client/cached_dir.h
index 73e28b04b519..537730a74867 100644
--- a/fs/smb/client/cached_dir.h
+++ b/fs/smb/client/cached_dir.h
@@ -55,11 +55,15 @@ struct cached_fids {
 	int num_entries;
 	struct list_head entries;
 	struct delayed_work laundromat_work;
+
+	/* convenience for CFID_LOOKUP_PARENT */
+	int dirsep;
 };
 
 /* Lookup modes for find_cached_dir() */
 enum {
 	CFID_LOOKUP_PATH,
+	CFID_LOOKUP_PARENT,
 	CFID_LOOKUP_DENTRY,
 	CFID_LOOKUP_LEASEKEY,
 };