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 (file)
--- 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;
+       }
+
+       tcon = cifs_sb_master_tcon(cifs_sb);
+       if (!tcon) {
+               cifs_dbg(FYI, "%s: master tcon is NULL\n", __func__);
                goto free_full_path;
        }
-       ses = tlink_tcon(tlink)->ses;
 
+       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);
+
+       ses = tcon->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;
+       /*
+        * 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);
        }
 
-       /* no valid submounts were found; return error from get_dfs_path() by
-        * preference */
-       if (rc != 0)
+       free_xid(xid);
+
+       if (rc) {
                mnt = ERR_PTR(rc);
+               goto free_root_path;
+       }
 
-success:
-       free_dfs_info_array(referrals, num_referrals);
+       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:

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 865706e..62d48d4 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -52,6 +52,9 @@
 #include "cifs_spnego.h"
 #include "fscache.h"
 #include "smb2pdu.h"
+#ifdef CONFIG_CIFS_DFS_UPCALL
+#include "dfs_cache.h"
+#endif
 
 int cifsFYI = 0;
 bool traceSMB;
@@ -1494,10 +1497,15 @@ init_cifs(void)
        if (rc)
                goto out_destroy_mids;
 
+#ifdef CONFIG_CIFS_DFS_UPCALL
+       rc = dfs_cache_init();
+       if (rc)
+               goto out_destroy_request_bufs;
+#endif /* CONFIG_CIFS_DFS_UPCALL */
 #ifdef CONFIG_CIFS_UPCALL
        rc = init_cifs_spnego();
        if (rc)
-               goto out_destroy_request_bufs;
+               goto out_destroy_dfs_cache;
 #endif /* CONFIG_CIFS_UPCALL */
 
 #ifdef CONFIG_CIFS_ACL
@@ -1525,6 +1533,10 @@ out_register_key_type:
 #endif
 #ifdef CONFIG_CIFS_UPCALL
        exit_cifs_spnego();
+out_destroy_dfs_cache:
+#endif
+#ifdef CONFIG_CIFS_DFS_UPCALL
+       dfs_cache_destroy();
 out_destroy_request_bufs:
 #endif
        cifs_destroy_request_bufs();
@@ -1556,6 +1568,9 @@ exit_cifs(void)
 #ifdef CONFIG_CIFS_UPCALL
        exit_cifs_spnego();
 #endif
+#ifdef CONFIG_CIFS_DFS_UPCALL
+       dfs_cache_destroy();
+#endif
        cifs_destroy_request_bufs();
        cifs_destroy_mids();
        cifs_destroy_inodecache();

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 66c4876..45feb3f 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1551,7 +1551,6 @@ static inline void free_dfs_info_param(struct dfs_info3_param *param)
        if (param) {
                kfree(param->path_name);
                kfree(param->node_name);
-               kfree(param);
        }
 }
 

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index efa5e36..f277bc5 100644 (file)
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -22,6 +22,9 @@
 #define _CIFSPROTO_H
 #include <linux/nls.h>
 #include "trace.h"
+#ifdef CONFIG_CIFS_DFS_UPCALL
+#include "dfs_cache.h"
+#endif
 
 struct statfs;
 struct smb_vol;
@@ -294,11 +297,6 @@ extern int CIFSGetDFSRefer(const unsigned int xid, struct cifs_ses *ses,
                           unsigned int *num_of_nodes,
                           const struct nls_table *nls_codepage, int remap);
 
-extern int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,
-                       const char *old_path,
-                       const struct nls_table *nls_codepage,
-                       unsigned int *num_referrals,
-                       struct dfs_info3_param **referrals, int remap);
 extern int parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
                               unsigned int *num_of_nodes,
                               struct dfs_info3_param **target_nodes,
@@ -567,4 +565,15 @@ void cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc);
 extern void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
                                unsigned int *len, unsigned int *offset);
 
+#ifdef CONFIG_CIFS_DFS_UPCALL
+static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,
+                              const char *old_path,
+                              const struct nls_table *nls_codepage,
+                              struct dfs_info3_param *referral, int remap)
+{
+       return dfs_cache_find(xid, ses, nls_codepage, remap, old_path,
+                             referral, NULL);
+}
+#endif
+
 #endif                 /* _CIFSPROTO_H */

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 5feb3bf..182b16e 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -56,6 +56,10 @@
 #include "fscache.h"
 #include "smb2proto.h"
 #include "smbdirect.h"
+#include "dns_resolve.h"
+#ifdef CONFIG_CIFS_DFS_UPCALL
+#include "dfs_cache.h"
+#endif
 
 extern mempool_t *cifs_req_poolp;
 extern bool disable_legacy_dialects;
@@ -3262,25 +3266,6 @@ out:
        return rc;
 }
 
-int
-get_dfs_path(const unsigned int xid, struct cifs_ses *ses, const char *old_path,
-            const struct nls_table *nls_codepage, unsigned int *num_referrals,
-            struct dfs_info3_param **referrals, int remap)
-{
-       int rc = 0;
-
-       if (!ses->server->ops->get_dfs_refer)
-               return -ENOSYS;
-
-       *num_referrals = 0;
-       *referrals = NULL;
-
-       rc = ses->server->ops->get_dfs_refer(xid, ses, old_path,
-                                            referrals, num_referrals,
-                                            nls_codepage, remap);
-       return rc;
-}
-
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 static struct lock_class_key cifs_key[2];
 static struct lock_class_key cifs_slock_key[2];
@@ -3931,8 +3916,9 @@ build_unc_path_to_root(const struct smb_vol *vol,
        return full_path;
 }
 
-/*
- * Perform a dfs referral query for a share and (optionally) prefix
+/**
+ * expand_dfs_referral - Perform a dfs referral query and update the cifs_sb
+ *
  *
  * If a referral is found, cifs_sb->mountdata will be (re-)allocated
  * to a string containing updated options for the submount.  Otherwise it
@@ -3947,8 +3933,7 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
                    int check_prefix)
 {
        int rc;
-       unsigned int num_referrals = 0;
-       struct dfs_info3_param *referrals = NULL;
+       struct dfs_info3_param referral = {0};
        char *full_path = NULL, *ref_path = NULL, *mdata = NULL;
 
        if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
@@ -3961,17 +3946,15 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
        /* For DFS paths, skip the first '\' of the UNC */
        ref_path = check_prefix ? full_path + 1 : volume_info->UNC + 1;
 
-       rc = get_dfs_path(xid, ses, ref_path, cifs_sb->local_nls,
-                         &num_referrals, &referrals, cifs_remap(cifs_sb));
-
-       if (!rc && num_referrals > 0) {
+       rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
+                           ref_path, &referral, NULL);
+       if (!rc) {
                char *fake_devname = NULL;
 
                mdata = cifs_compose_mount_options(cifs_sb->mountdata,
-                                                  full_path + 1, referrals,
+                                                  full_path + 1, &referral,
                                                   &fake_devname);
-
-               free_dfs_info_array(referrals, num_referrals);
+               free_dfs_info_param(&referral);
 
                if (IS_ERR(mdata)) {
                        rc = PTR_ERR(mdata);
@@ -3979,7 +3962,7 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
                } else {
                        cifs_cleanup_volume_info_contents(volume_info);
                        rc = cifs_setup_volume_info(volume_info, mdata,
-                                                       fake_devname, false);
+                                                   fake_devname, false);
                }
                kfree(fake_devname);
                kfree(cifs_sb->mountdata);

diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index 378151e..32a6c02 100644 (file)
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -929,19 +929,18 @@ cifs_unix_dfs_readlink(const unsigned int xid, struct cifs_tcon *tcon,
 {
 #ifdef CONFIG_CIFS_DFS_UPCALL
        int rc;
-       unsigned int num_referrals = 0;
-       struct dfs_info3_param *referrals = NULL;
+       struct dfs_info3_param referral = {0};
 
-       rc = get_dfs_path(xid, tcon->ses, searchName, nls_codepage,
-                         &num_referrals, &referrals, 0);
+       rc = get_dfs_path(xid, tcon->ses, searchName, nls_codepage, &referral,
+                         0);
 
-       if (!rc && num_referrals > 0) {
-               *symlinkinfo = kstrndup(referrals->node_name,
-                                       strlen(referrals->node_name),
+       if (!rc) {
+               *symlinkinfo = kstrndup(referral.node_name,
+                                       strlen(referral.node_name),
                                        GFP_KERNEL);
+               free_dfs_info_param(&referral);
                if (!*symlinkinfo)
                        rc = -ENOMEM;
-               free_dfs_info_array(referrals, num_referrals);
        }
        return rc;
 #else /* No DFS support */