From f8590e1a2cb56880919f1a4bed20f6d161921b52 Mon Sep 17 00:00:00 2001
From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Wed, 12 Oct 2022 06:13:03 -0500
Subject: [PATCH] cifs: find and use the dentry for cached non-root directories
also
This allows us to use cached attributes for the entries in a cached
directory for as long as a lease is held on the directory itself.
Previously we have always allowed "used cached attributes for 1 second"
but this extends this to the lifetime of the lease as well as making the
caching safer.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
fs/cifs/cached_dir.c | 63 ++++++++++++++++++++++++++++++++++----------
1 file changed, 49 insertions(+), 14 deletions(-)
@@ -5,6 +5,7 @@
* Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
*/
+#include <linux/namei.h>
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
@@ -59,6 +60,44 @@ static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids,
return cfid;
}
+static struct dentry *
+path_to_dentry(struct cifs_sb_info *cifs_sb, const char *path)
+{
+ struct dentry *dentry;
+ const char *s, *p;
+ char sep;
+
+ sep = CIFS_DIR_SEP(cifs_sb);
+ dentry = dget(cifs_sb->root);
+ s = path;
+
+ do {
+ struct inode *dir = d_inode(dentry);
+ struct dentry *child;
+
+ if (!S_ISDIR(dir->i_mode)) {
+ dput(dentry);
+ dentry = ERR_PTR(-ENOTDIR);
+ break;
+ }
+
+ /* skip separators */
+ while (*s == sep)
+ s++;
+ if (!*s)
+ break;
+ p = s++;
+ /* next separator */
+ while (*s && *s != sep)
+ s++;
+
+ child = lookup_positive_unlocked(p, dentry, s - p);
+ dput(dentry);
+ dentry = child;
+ } while (!IS_ERR(dentry));
+ return dentry;
+}
+
/*
* Open the and cache a directory handle.
* If error then *cfid is not initialized.
@@ -86,7 +125,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
struct cached_fid *cfid;
struct cached_fids *cfids;
-
if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache ||
is_smb1_server(tcon->ses->server))
return -EOPNOTSUPP;
@@ -101,13 +139,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
if (cifs_sb->root == NULL)
return -ENOENT;
- /*
- * TODO: for better caching we need to find and use the dentry also
- * for non-root directories.
- */
- if (!path[0])
- dentry = cifs_sb->root;
-
utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
if (!utf16_path)
return -ENOMEM;
@@ -199,12 +230,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
#endif /* CIFS_DEBUG2 */
- cfid->tcon = tcon;
- if (dentry) {
- cfid->dentry = dentry;
- dget(dentry);
- }
- /* BB TBD check to see if oplock level check can be removed below */
if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)
goto oshr_free;
@@ -223,6 +248,16 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
&rsp_iov[1], sizeof(struct smb2_file_all_info),
(char *)&cfid->file_all_info))
cfid->file_all_info_is_valid = true;
+
+ if (!path[0])
+ dentry = dget(cifs_sb->root);
+ else {
+ dentry = path_to_dentry(cifs_sb, path);
+ if (IS_ERR(dentry))
+ goto oshr_free;
+ }
+ cfid->dentry = dentry;
+ cfid->tcon = tcon;
cfid->time = jiffies;
cfid->is_open = true;
cfid->has_lease = true;
--
2.34.1