cifs: Fix mount options set in automount

Starting from 4a367dc04435, we must set the mount options based on the
DFS full path rather than the resolved target, that is, cifs_mount()
will be responsible for resolving the DFS link (cached) as well as
performing failover to any other targets in the referral.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reported-by: Martijn de Gouw <martijn.de.gouw@prodrive-technologies.com>
Fixes: 4a367dc04435 ("cifs: Add support for failover in cifs_mount()")
Link: https://lore.kernel.org/linux-cifs/39643d7d-2abb-14d3-ced6-c394fab9a777@prodrive-technologies.com
Tested-by: Martijn de Gouw <martijn.de.gouw@prodrive-technologies.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 41957b8..606f26d 100644 (file)
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -120,17 +120,17 @@ cifs_build_devname(char *nodename, const char *prepath)
 
 
 /**
- * cifs_compose_mount_options  -       creates mount options for refferral
+ * cifs_compose_mount_options  -       creates mount options for referral
  * @sb_mountdata:      parent/root DFS mount options (template)
  * @fullpath:          full path in UNC format
- * @ref:               server's referral
+ * @ref:               optional server's referral
  * @devname:           optional pointer for saving device name
  *
  * creates mount options for submount based on template options sb_mountdata
  * and replacing unc,ip,prefixpath options with ones we've got form ref_unc.
  *
  * Returns: pointer to new mount options or ERR_PTR.
- * Caller is responcible for freeing retunrned value if it is not error.
+ * Caller is responsible for freeing returned value if it is not error.
  */
 char *cifs_compose_mount_options(const char *sb_mountdata,
                                   const char *fullpath,
@@ -150,18 +150,27 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
        if (sb_mountdata == NULL)
                return ERR_PTR(-EINVAL);
 
-       if (strlen(fullpath) - ref->path_consumed) {
-               prepath = fullpath + ref->path_consumed;
-               /* skip initial delimiter */
-               if (*prepath == '/' || *prepath == '\\')
-                       prepath++;
-       }
+       if (ref) {
+               if (strlen(fullpath) - ref->path_consumed) {
+                       prepath = fullpath + ref->path_consumed;
+                       /* skip initial delimiter */
+                       if (*prepath == '/' || *prepath == '\\')
+                               prepath++;
+               }
 
-       name = cifs_build_devname(ref->node_name, prepath);
-       if (IS_ERR(name)) {
-               rc = PTR_ERR(name);
-               name = NULL;
-               goto compose_mount_options_err;
+               name = cifs_build_devname(ref->node_name, prepath);
+               if (IS_ERR(name)) {
+                       rc = PTR_ERR(name);
+                       name = NULL;
+                       goto compose_mount_options_err;
+               }
+       } else {
+               name = cifs_build_devname((char *)fullpath, NULL);
+               if (IS_ERR(name)) {
+                       rc = PTR_ERR(name);
+                       name = NULL;
+                       goto compose_mount_options_err;
+               }
        }
 
        rc = dns_resolve_server_name_to_ip(name, &srvIP);
@@ -225,6 +234,8 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
 
        if (devname)
                *devname = name;
+       else
+               kfree(name);
 
        /*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/
        /*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/
@@ -241,23 +252,23 @@ compose_mount_options_err:
 }
 
 /**
- * cifs_dfs_do_refmount - mounts specified path using provided refferal
+ * cifs_dfs_do_mount - mounts specified path using DFS full path
+ *
+ * Always pass down @fullpath to smb3_do_mount() so we can use the root server
+ * to perform failover in case we failed to connect to the first target in the
+ * referral.
+ *
  * @cifs_sb:           parent/root superblock
  * @fullpath:          full path in UNC format
- * @ref:               server's referral
  */
-static struct vfsmount *cifs_dfs_do_refmount(struct dentry *mntpt,
-               struct cifs_sb_info *cifs_sb,
-               const char *fullpath, const struct dfs_info3_param *ref)
+static struct vfsmount *cifs_dfs_do_mount(struct dentry *mntpt,
+                                         struct cifs_sb_info *cifs_sb,
+                                         const char *fullpath)
 {
        struct vfsmount *mnt;
        char *mountdata;
        char *devname;
 
-       /*
-        * Always pass down the DFS full path to smb3_do_mount() so we
-        * can use it later for failover.
-        */
        devname = kstrndup(fullpath, strlen(fullpath), GFP_KERNEL);
        if (!devname)
                return ERR_PTR(-ENOMEM);
@@ -266,7 +277,7 @@ static struct vfsmount *cifs_dfs_do_refmount(struct dentry *mntpt,
 
        /* strip first '\' from fullpath */
        mountdata = cifs_compose_mount_options(cifs_sb->mountdata,
-                                              fullpath + 1, ref, NULL);
+                                              fullpath + 1, NULL, NULL);
        if (IS_ERR(mountdata)) {
                kfree(devname);
                return (struct vfsmount *)mountdata;
@@ -278,28 +289,16 @@ static struct vfsmount *cifs_dfs_do_refmount(struct dentry *mntpt,
        return mnt;
 }
 
-static void dump_referral(const struct dfs_info3_param *ref)
-{
-       cifs_dbg(FYI, "DFS: ref path: %s\n", ref->path_name);
-       cifs_dbg(FYI, "DFS: node path: %s\n", ref->node_name);
-       cifs_dbg(FYI, "DFS: fl: %d, srv_type: %d\n",
-                ref->flags, ref->server_type);
-       cifs_dbg(FYI, "DFS: ref_flags: %d, path_consumed: %d\n",
-                ref->ref_flag, ref->path_consumed);
-}
-
 /*
  * Create a vfsmount that we can automount
  */
 static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
 {
-       struct dfs_info3_param referral = {0};
        struct cifs_sb_info *cifs_sb;
        struct cifs_ses *ses;
        struct cifs_tcon *tcon;
        char *full_path, *root_path;
        unsigned int xid;
-       int len;
        int rc;
        struct vfsmount *mnt;
 
@@ -357,7 +356,7 @@ static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
        if (!rc) {
                rc = dfs_cache_find(xid, ses, cifs_sb->local_nls,
                                    cifs_remap(cifs_sb), full_path + 1,
-                                   &referral, NULL);
+                                   NULL, NULL);
        }
 
        free_xid(xid);
@@ -366,26 +365,16 @@ static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
                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.
+        * OK - we were able to get and cache a referral for @full_path.
+        *
+        * Now, pass it down to cifs_mount() and it will retry every available
+        * node server in case of failures - no need to do it here.
         */
-       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);
+       mnt = cifs_dfs_do_mount(mntpt, cifs_sb, full_path);
+       cifs_dbg(FYI, "%s: cifs_dfs_do_mount:%s , mnt:%p\n", __func__,
+                full_path + 1, mnt);
 
-free_dfs_ref:
-       free_dfs_info_param(&referral);
 free_root_path:
        kfree(root_path);
 free_full_path: