cifs: Make use of DFS cache to get new DFS referrals
This patch will make use of DFS cache routines where appropriate and
do not always request a new referral from server.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index 7adbdf9..6e6953f 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -25,6 +25,7 @@
#include "dns_resolve.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
+#include "dfs_cache.h"
static LIST_HEAD(cifs_dfs_automount_list);
@@ -285,16 +286,16 @@ static void dump_referral(const struct dfs_info3_param *ref)
*/
static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
{
- struct dfs_info3_param *referrals = NULL;
- unsigned int num_referrals = 0;
+ struct dfs_info3_param referral = {0};
struct cifs_sb_info *cifs_sb;
struct cifs_ses *ses;
- char *full_path;
+ struct cifs_tcon *tcon;
+ char *full_path, *root_path;
unsigned int xid;
- int i;
+ int len;
int rc;
struct vfsmount *mnt;
- struct tcon_link *tlink;
+ char sep;
cifs_dbg(FYI, "in %s\n", __func__);
BUG_ON(IS_ROOT(mntpt));
@@ -313,53 +314,76 @@ static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
goto cdda_exit;
}
+ sep = CIFS_DIR_SEP(cifs_sb);
+
/* always use tree name prefix */
full_path = build_path_from_dentry_optional_prefix(mntpt, true);
if (full_path == NULL)
goto cdda_exit;
- tlink = cifs_sb_tlink(cifs_sb);
- if (IS_ERR(tlink)) {
- mnt = ERR_CAST(tlink);
+ cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
+
+ if (!cifs_sb_master_tlink(cifs_sb)) {
+ cifs_dbg(FYI, "%s: master tlink is NULL\n", __func__);
goto free_full_path;
}
- ses = tlink_tcon(tlink)->ses;
- xid = get_xid();
- rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls,
- &num_referrals, &referrals,
- cifs_remap(cifs_sb));
- free_xid(xid);
-
- cifs_put_tlink(tlink);
-
- mnt = ERR_PTR(-ENOENT);
- for (i = 0; i < num_referrals; i++) {
- int len;
- dump_referral(referrals + i);
- /* connect to a node */
- len = strlen(referrals[i].node_name);
- if (len < 2) {
- cifs_dbg(VFS, "%s: Net Address path too short: %s\n",
- __func__, referrals[i].node_name);
- mnt = ERR_PTR(-EINVAL);
- break;
- }
- mnt = cifs_dfs_do_refmount(mntpt, cifs_sb,
- full_path, referrals + i);
- cifs_dbg(FYI, "%s: cifs_dfs_do_refmount:%s , mnt:%p\n",
- __func__, referrals[i].node_name, mnt);
- if (!IS_ERR(mnt))
- goto success;
+ tcon = cifs_sb_master_tcon(cifs_sb);
+ if (!tcon) {
+ cifs_dbg(FYI, "%s: master tcon is NULL\n", __func__);
+ goto free_full_path;
}
- /* no valid submounts were found; return error from get_dfs_path() by
- * preference */
- if (rc != 0)
- mnt = ERR_PTR(rc);
+ root_path = kstrdup(tcon->treeName, GFP_KERNEL);
+ if (!root_path) {
+ mnt = ERR_PTR(-ENOMEM);
+ goto free_full_path;
+ }
+ cifs_dbg(FYI, "%s: root path: %s\n", __func__, root_path);
-success:
- free_dfs_info_array(referrals, num_referrals);
+ ses = tcon->ses;
+ xid = get_xid();
+
+ /*
+ * If DFS root has been expired, then unconditionally fetch it again to
+ * refresh DFS referral cache.
+ */
+ rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
+ root_path + 1, NULL, NULL);
+ if (!rc) {
+ rc = dfs_cache_find(xid, ses, cifs_sb->local_nls,
+ cifs_remap(cifs_sb), full_path + 1,
+ &referral, NULL);
+ }
+
+ free_xid(xid);
+
+ if (rc) {
+ mnt = ERR_PTR(rc);
+ goto free_root_path;
+ }
+
+ dump_referral(&referral);
+
+ len = strlen(referral.node_name);
+ if (len < 2) {
+ cifs_dbg(VFS, "%s: Net Address path too short: %s\n",
+ __func__, referral.node_name);
+ mnt = ERR_PTR(-EINVAL);
+ goto free_dfs_ref;
+ }
+ /*
+ * cifs_mount() will retry every available node server in case
+ * of failures.
+ */
+ mnt = cifs_dfs_do_refmount(mntpt, cifs_sb, full_path, &referral);
+ cifs_dbg(FYI, "%s: cifs_dfs_do_refmount:%s , mnt:%p\n", __func__,
+ referral.node_name, mnt);
+
+free_dfs_ref:
+ free_dfs_info_param(&referral);
+free_root_path:
+ kfree(root_path);
free_full_path:
kfree(full_path);
cdda_exit: