Merge branch 'mnt_devname' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'mnt_devname' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  vfs: bury ->get_sb()
  nfs: switch NFS from ->get_sb() to ->mount()
  nfs: stop mangling ->mnt_devname on NFS
  vfs: new superblock methods to override /proc/*/mount{s,info}
  nfs: nfs_do_{ref,sub}mount() superblock argument is redundant
  nfs: make nfs_path() work without vfsmount
  nfs: store devname at disconnected NFS roots
  nfs: propagate devname to nfs{,4}_get_root()

7 files changed, 237 insertions, 160 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 2c3eb33b904d..abdf38d5971d 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1169,11 +1169,23 @@ static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
         iput(inode);
 }
 
+static void nfs_d_release(struct dentry *dentry)
+{
+        /* free cached devname value, if it survived that far */
+        if (unlikely(dentry->d_fsdata)) {
+                if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+                        WARN_ON(1);
+                else
+                        kfree(dentry->d_fsdata);
+        }
+}
+
 const struct dentry_operations nfs_dentry_operations = {
         .d_revalidate   = nfs_lookup_revalidate,
         .d_delete       = nfs_dentry_delete,
         .d_iput         = nfs_dentry_iput,
         .d_automount    = nfs_d_automount,
+        .d_release      = nfs_d_release,
 };
 
 static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
@@ -1248,6 +1260,7 @@ const struct dentry_operations nfs4_dentry_operations = {
         .d_delete       = nfs_dentry_delete,
         .d_iput         = nfs_dentry_iput,
         .d_automount    = nfs_d_automount,
+        .d_release      = nfs_d_release,
 };
 
 /*
diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index b5ffe8fa291f..1084792bc0fe 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -75,18 +75,25 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i
 /*
  * get an NFS2/NFS3 root dentry from the root filehandle
  */
-struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
+struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
+                            const char *devname)
 {
         struct nfs_server *server = NFS_SB(sb);
         struct nfs_fsinfo fsinfo;
         struct dentry *ret;
         struct inode *inode;
+        void *name = kstrdup(devname, GFP_KERNEL);
         int error;
 
+        if (!name)
+                return ERR_PTR(-ENOMEM);
+
         /* get the actual root for this mount */
         fsinfo.fattr = nfs_alloc_fattr();
-        if (fsinfo.fattr == NULL)
+        if (fsinfo.fattr == NULL) {
+                kfree(name);
                 return ERR_PTR(-ENOMEM);
+        }
 
         error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
         if (error < 0) {
@@ -119,7 +126,15 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
         }
 
         security_d_instantiate(ret, inode);
+        spin_lock(&ret->d_lock);
+        if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
+                ret->d_fsdata = name;
+                name = NULL;
+        }
+        spin_unlock(&ret->d_lock);
 out:
+        if (name)
+                kfree(name);
         nfs_free_fattr(fsinfo.fattr);
         return ret;
 }
@@ -169,27 +184,35 @@ out:
 /*
  * get an NFS4 root dentry from the root filehandle
  */
-struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
+struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh,
+                             const char *devname)
 {
         struct nfs_server *server = NFS_SB(sb);
         struct nfs_fattr *fattr = NULL;
         struct dentry *ret;
         struct inode *inode;
+        void *name = kstrdup(devname, GFP_KERNEL);
         int error;
 
         dprintk("--> nfs4_get_root()\n");
 
+        if (!name)
+                return ERR_PTR(-ENOMEM);
+
         /* get the info about the server and filesystem */
         error = nfs4_server_capabilities(server, mntfh);
         if (error < 0) {
                 dprintk("nfs_get_root: getcaps error = %d\n",
                         -error);
+                kfree(name);
                 return ERR_PTR(error);
         }
 
         fattr = nfs_alloc_fattr();
-        if (fattr == NULL)
-                return ERR_PTR(-ENOMEM);;
+        if (fattr == NULL) {
+                kfree(name);
+                return ERR_PTR(-ENOMEM);
+        }
 
         /* get the actual root for this mount */
         error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
@@ -223,8 +246,15 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
         }
 
         security_d_instantiate(ret, inode);
-
+        spin_lock(&ret->d_lock);
+        if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
+                ret->d_fsdata = name;
+                name = NULL;
+        }
+        spin_unlock(&ret->d_lock);
 out:
+        if (name)
+                kfree(name);
         nfs_free_fattr(fattr);
         dprintk("<-- nfs4_get_root()\n");
         return ret;
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index cf9fdbdabc67..e94ad22da5d2 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -163,10 +163,10 @@ static inline void nfs_fs_proc_exit(void)
 
 /* nfs4namespace.c */
 #ifdef CONFIG_NFS_V4
-extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry);
+extern struct vfsmount *nfs_do_refmount(struct dentry *dentry);
 #else
 static inline
-struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
+struct vfsmount *nfs_do_refmount(struct dentry *dentry)
 {
         return ERR_PTR(-ENOENT);
 }
@@ -247,16 +247,16 @@ extern void nfs_sb_active(struct super_block *sb);
 extern void nfs_sb_deactive(struct super_block *sb);
 
 /* namespace.c */
-extern char *nfs_path(const char *base,
-                      const struct dentry *droot,
-                      const struct dentry *dentry,
+extern char *nfs_path(char **p, struct dentry *dentry,
                       char *buffer, ssize_t buflen);
 extern struct vfsmount *nfs_d_automount(struct path *path);
 
 /* getroot.c */
-extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *);
+extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *,
+                                   const char *);
 #ifdef CONFIG_NFS_V4
-extern struct dentry *nfs4_get_root(struct super_block *, struct nfs_fh *);
+extern struct dentry *nfs4_get_root(struct super_block *, struct nfs_fh *,
+                                    const char *);
 
 extern int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh);
 #endif
@@ -288,12 +288,11 @@ extern int _nfs4_call_sync_session(struct nfs_server *server,
 /*
  * Determine the device name as a string
  */
-static inline char *nfs_devname(const struct vfsmount *mnt_parent,
-                                const struct dentry *dentry,
+static inline char *nfs_devname(struct dentry *dentry,
                                 char *buffer, ssize_t buflen)
 {
-        return nfs_path(mnt_parent->mnt_devname, mnt_parent->mnt_root,
-                        dentry, buffer, buflen);
+        char *dummy;
+        return nfs_path(&dummy, dentry, buffer, buflen);
 }
 
 /*
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index f32b8603dca8..c0b8344db0c6 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -25,33 +25,30 @@ static LIST_HEAD(nfs_automount_list);
 static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
 int nfs_mountpoint_expiry_timeout = 500 * HZ;
 
-static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
-                                        const struct dentry *dentry,
+static struct vfsmount *nfs_do_submount(struct dentry *dentry,
                                         struct nfs_fh *fh,
                                         struct nfs_fattr *fattr);
 
 /*
  * nfs_path - reconstruct the path given an arbitrary dentry
- * @base - arbitrary string to prepend to the path
- * @droot - pointer to root dentry for mountpoint
+ * @base - used to return pointer to the end of devname part of path
  * @dentry - pointer to dentry
  * @buffer - result buffer
  * @buflen - length of buffer
  *
- * Helper function for constructing the path from the
- * root dentry to an arbitrary hashed dentry.
+ * Helper function for constructing the server pathname
+ * by arbitrary hashed dentry.
  *
  * This is mainly for use in figuring out the path on the
- * server side when automounting on top of an existing partition.
+ * server side when automounting on top of an existing partition
+ * and in generating /proc/mounts and friends.
  */
-char *nfs_path(const char *base,
-               const struct dentry *droot,
-               const struct dentry *dentry,
-               char *buffer, ssize_t buflen)
+char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen)
 {
         char *end;
         int namelen;
         unsigned seq;
+        const char *base;
 
 rename_retry:
         end = buffer+buflen;
@@ -60,7 +57,10 @@ rename_retry:
 
         seq = read_seqbegin(&rename_lock);
         rcu_read_lock();
-        while (!IS_ROOT(dentry) && dentry != droot) {
+        while (1) {
+                spin_lock(&dentry->d_lock);
+                if (IS_ROOT(dentry))
+                        break;
                 namelen = dentry->d_name.len;
                 buflen -= namelen + 1;
                 if (buflen < 0)
@@ -68,27 +68,47 @@ rename_retry:
                 end -= namelen;
                 memcpy(end, dentry->d_name.name, namelen);
                 *--end = '/';
+                spin_unlock(&dentry->d_lock);
                 dentry = dentry->d_parent;
         }
-        rcu_read_unlock();
-        if (read_seqretry(&rename_lock, seq))
+        if (read_seqretry(&rename_lock, seq)) {
+                spin_unlock(&dentry->d_lock);
+                rcu_read_unlock();
                 goto rename_retry;
+        }
         if (*end != '/') {
-                if (--buflen < 0)
+                if (--buflen < 0) {
+                        spin_unlock(&dentry->d_lock);
+                        rcu_read_unlock();
                         goto Elong;
+                }
                 *--end = '/';
         }
+        *p = end;
+        base = dentry->d_fsdata;
+        if (!base) {
+                spin_unlock(&dentry->d_lock);
+                rcu_read_unlock();
+                WARN_ON(1);
+                return end;
+        }
         namelen = strlen(base);
         /* Strip off excess slashes in base string */
         while (namelen > 0 && base[namelen - 1] == '/')
                 namelen--;
         buflen -= namelen;
-        if (buflen < 0)
+        if (buflen < 0) {
+                spin_lock(&dentry->d_lock);
+                rcu_read_unlock();
                 goto Elong;
+        }
         end -= namelen;
         memcpy(end, base, namelen);
+        spin_unlock(&dentry->d_lock);
+        rcu_read_unlock();
         return end;
 Elong_unlock:
+        spin_lock(&dentry->d_lock);
         rcu_read_unlock();
         if (read_seqretry(&rename_lock, seq))
                 goto rename_retry;
@@ -143,9 +163,9 @@ struct vfsmount *nfs_d_automount(struct path *path)
         }
 
         if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
-                mnt = nfs_do_refmount(path->mnt, path->dentry);
+                mnt = nfs_do_refmount(path->dentry);
         else
-                mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr);
+                mnt = nfs_do_submount(path->dentry, fh, fattr);
         if (IS_ERR(mnt))
                 goto out;
 
@@ -209,19 +229,17 @@ static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
 
 /**
  * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
- * @mnt_parent - mountpoint of parent directory
  * @dentry - parent directory
  * @fh - filehandle for new root dentry
  * @fattr - attributes for new root inode
  *
  */
-static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
-                                        const struct dentry *dentry,
+static struct vfsmount *nfs_do_submount(struct dentry *dentry,
                                         struct nfs_fh *fh,
                                         struct nfs_fattr *fattr)
 {
         struct nfs_clone_mount mountdata = {
-                .sb = mnt_parent->mnt_sb,
+                .sb = dentry->d_sb,
                 .dentry = dentry,
                 .fh = fh,
                 .fattr = fattr,
@@ -237,11 +255,11 @@ static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
                         dentry->d_name.name);
         if (page == NULL)
                 goto out;
-        devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);
+        devname = nfs_devname(dentry, page, PAGE_SIZE);
         mnt = (struct vfsmount *)devname;
         if (IS_ERR(devname))
                 goto free_page;
-        mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata);
+        mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
 free_page:
         free_page((unsigned long)page);
 out:
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 3c2a1724fbd2..bb80c49b6533 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -54,33 +54,29 @@ Elong:
 /*
  * Determine the mount path as a string
  */
-static char *nfs4_path(const struct vfsmount *mnt_parent,
-                       const struct dentry *dentry,
-                       char *buffer, ssize_t buflen)
+static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
 {
-        const char *srvpath;
-
-        srvpath = strchr(mnt_parent->mnt_devname, ':');
-        if (srvpath)
-                srvpath++;
-        else
-                srvpath = mnt_parent->mnt_devname;
-
-        return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
+        char *limit;
+        char *path = nfs_path(&limit, dentry, buffer, buflen);
+        if (!IS_ERR(path)) {
+                char *colon = strchr(path, ':');
+                if (colon && colon < limit)
+                        path = colon + 1;
+        }
+        return path;
 }
 
 /*
  * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
  * believe to be the server path to this dentry
  */
-static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
-                                const struct dentry *dentry,
+static int nfs4_validate_fspath(struct dentry *dentry,
                                 const struct nfs4_fs_locations *locations,
                                 char *page, char *page2)
 {
         const char *path, *fs_path;
 
-        path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
+        path = nfs4_path(dentry, page, PAGE_SIZE);
         if (IS_ERR(path))
                 return PTR_ERR(path);
 
@@ -165,20 +161,18 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 
 /**
  * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
- * @mnt_parent - mountpoint of parent directory
  * @dentry - parent directory
  * @locations - array of NFSv4 server location information
  *
  */
-static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
-                                            const struct dentry *dentry,
+static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
                                             const struct nfs4_fs_locations *locations)
 {
         struct vfsmount *mnt = ERR_PTR(-ENOENT);
         struct nfs_clone_mount mountdata = {
-                .sb = mnt_parent->mnt_sb,
+                .sb = dentry->d_sb,
                 .dentry = dentry,
-                .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
+                .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
         };
         char *page = NULL, *page2 = NULL;
         int loc, error;
@@ -198,7 +192,7 @@ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
                 goto out;
 
         /* Ensure fs path is a prefix of current dentry path */
-        error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
+        error = nfs4_validate_fspath(dentry, locations, page, page2);
         if (error < 0) {
                 mnt = ERR_PTR(error);
                 goto out;
@@ -225,11 +219,10 @@ out:
 
 /*
  * nfs_do_refmount - handle crossing a referral on server
- * @mnt_parent - mountpoint of referral
  * @dentry - dentry of referral
  *
  */
-struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
+struct vfsmount *nfs_do_refmount(struct dentry *dentry)
 {
         struct vfsmount *mnt = ERR_PTR(-ENOMEM);
         struct dentry *parent;
@@ -262,7 +255,7 @@ struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentr
             fs_locations->fs_path.ncomponents <= 0)
                 goto out_free;
 
-        mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
+        mnt = nfs_follow_referral(dentry, fs_locations);
 out_free:
         __free_page(page);
         kfree(fs_locations);
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index b68c8607770f..d3286583009a 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -263,8 +263,11 @@ static match_table_t nfs_local_lock_tokens = {
 static void nfs_umount_begin(struct super_block *);
 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
+static int  nfs_show_devname(struct seq_file *, struct vfsmount *);
+static int  nfs_show_path(struct seq_file *, struct vfsmount *);
 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
-static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
+static struct dentry *nfs_fs_mount(struct file_system_type *,
+                int, const char *, void *);
 static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
                 int flags, const char *dev_name, void *raw_data);
 static void nfs_put_super(struct super_block *);
@@ -274,7 +277,7 @@ static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
 static struct file_system_type nfs_fs_type = {
         .owner          = THIS_MODULE,
         .name           = "nfs",
-        .get_sb         = nfs_get_sb,
+        .mount          = nfs_fs_mount,
         .kill_sb        = nfs_kill_super,
         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
@@ -296,6 +299,8 @@ static const struct super_operations nfs_sops = {
         .evict_inode    = nfs_evict_inode,
         .umount_begin   = nfs_umount_begin,
         .show_options   = nfs_show_options,
+        .show_devname   = nfs_show_devname,
+        .show_path      = nfs_show_path,
         .show_stats     = nfs_show_stats,
         .remount_fs     = nfs_remount,
 };
@@ -303,16 +308,16 @@ static const struct super_operations nfs_sops = {
 #ifdef CONFIG_NFS_V4
 static int nfs4_validate_text_mount_data(void *options,
         struct nfs_parsed_mount_data *args, const char *dev_name);
-static int nfs4_try_mount(int flags, const char *dev_name,
-        struct nfs_parsed_mount_data *data, struct vfsmount *mnt);
-static int nfs4_get_sb(struct file_system_type *fs_type,
-        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
+static struct dentry *nfs4_try_mount(int flags, const char *dev_name,
+        struct nfs_parsed_mount_data *data);
+static struct dentry *nfs4_mount(struct file_system_type *fs_type,
+        int flags, const char *dev_name, void *raw_data);
 static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *raw_data);
 static struct dentry *nfs4_xdev_mount(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *raw_data);
-static int nfs4_referral_get_sb(struct file_system_type *fs_type,
-        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
+static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
+        int flags, const char *dev_name, void *raw_data);
 static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *raw_data);
 static void nfs4_kill_super(struct super_block *sb);
@@ -320,7 +325,7 @@ static void nfs4_kill_super(struct super_block *sb);
 static struct file_system_type nfs4_fs_type = {
         .owner          = THIS_MODULE,
         .name           = "nfs4",
-        .get_sb         = nfs4_get_sb,
+        .mount          = nfs4_mount,
         .kill_sb        = nfs4_kill_super,
         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
@@ -352,7 +357,7 @@ static struct file_system_type nfs4_remote_referral_fs_type = {
 struct file_system_type nfs4_referral_fs_type = {
         .owner          = THIS_MODULE,
         .name           = "nfs4",
-        .get_sb         = nfs4_referral_get_sb,
+        .mount          = nfs4_referral_mount,
         .kill_sb        = nfs4_kill_super,
         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
@@ -366,6 +371,8 @@ static const struct super_operations nfs4_sops = {
         .evict_inode    = nfs4_evict_inode,
         .umount_begin   = nfs_umount_begin,
         .show_options   = nfs_show_options,
+        .show_devname   = nfs_show_devname,
+        .show_path      = nfs_show_path,
         .show_stats     = nfs_show_stats,
         .remount_fs     = nfs_remount,
 };
@@ -726,6 +733,28 @@ static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
         return 0;
 }
 
+static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt)
+{
+        char *page = (char *) __get_free_page(GFP_KERNEL);
+        char *devname, *dummy;
+        int err = 0;
+        if (!page)
+                return -ENOMEM;
+        devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE);
+        if (IS_ERR(devname))
+                err = PTR_ERR(devname);
+        else
+                seq_escape(m, devname, " \t\n\\");
+        free_page((unsigned long)page);
+        return err;
+}
+
+static int nfs_show_path(struct seq_file *m, struct vfsmount *mnt)
+{
+        seq_puts(m, "/");
+        return 0;
+}
+
 /*
  * Present statistical information for this VFS mountpoint
  */
@@ -2267,19 +2296,19 @@ static int nfs_bdi_register(struct nfs_server *server)
         return bdi_register_dev(&server->backing_dev_info, server->s_dev);
 }
 
-static int nfs_get_sb(struct file_system_type *fs_type,
-        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
+static struct dentry *nfs_fs_mount(struct file_system_type *fs_type,
+        int flags, const char *dev_name, void *raw_data)
 {
         struct nfs_server *server = NULL;
         struct super_block *s;
         struct nfs_parsed_mount_data *data;
         struct nfs_fh *mntfh;
-        struct dentry *mntroot;
+        struct dentry *mntroot = ERR_PTR(-ENOMEM);
         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
         struct nfs_sb_mountdata sb_mntdata = {
                 .mntflags = flags,
         };
-        int error = -ENOMEM;
+        int error;
 
         data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
         mntfh = nfs_alloc_fhandle();
@@ -2290,12 +2319,14 @@ static int nfs_get_sb(struct file_system_type *fs_type,
 
         /* Validate the mount data */
         error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
-        if (error < 0)
+        if (error < 0) {
+                mntroot = ERR_PTR(error);
                 goto out;
+        }
 
 #ifdef CONFIG_NFS_V4
         if (data->version == 4) {
-                error = nfs4_try_mount(flags, dev_name, data, mnt);
+                mntroot = nfs4_try_mount(flags, dev_name, data);
                 kfree(data->client_address);
                 kfree(data->nfs_server.export_path);
                 goto out;
@@ -2305,7 +2336,7 @@ static int nfs_get_sb(struct file_system_type *fs_type,
         /* Get a volume representation */
         server = nfs_create_server(data, mntfh);
         if (IS_ERR(server)) {
-                error = PTR_ERR(server);
+                mntroot = ERR_CAST(server);
                 goto out;
         }
         sb_mntdata.server = server;
@@ -2316,7 +2347,7 @@ static int nfs_get_sb(struct file_system_type *fs_type,
         /* Get a superblock - note that we may end up sharing one that already exists */
         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
         if (IS_ERR(s)) {
-                error = PTR_ERR(s);
+                mntroot = ERR_CAST(s);
                 goto out_err_nosb;
         }
 
@@ -2325,8 +2356,10 @@ static int nfs_get_sb(struct file_system_type *fs_type,
                 server = NULL;
         } else {
                 error = nfs_bdi_register(server);
-                if (error)
+                if (error) {
+                        mntroot = ERR_PTR(error);
                         goto error_splat_bdi;
+                }
         }
 
         if (!s->s_root) {
@@ -2336,20 +2369,15 @@ static int nfs_get_sb(struct file_system_type *fs_type,
                         s, data ? data->fscache_uniq : NULL, NULL);
         }
 
-        mntroot = nfs_get_root(s, mntfh);
-        if (IS_ERR(mntroot)) {
-                error = PTR_ERR(mntroot);
+        mntroot = nfs_get_root(s, mntfh, dev_name);
+        if (IS_ERR(mntroot))
                 goto error_splat_super;
-        }
 
         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
         if (error)
                 goto error_splat_root;
 
         s->s_flags |= MS_ACTIVE;
-        mnt->mnt_sb = s;
-        mnt->mnt_root = mntroot;
-        error = 0;
 
 out:
         kfree(data->nfs_server.hostname);
@@ -2359,7 +2387,7 @@ out:
 out_free_fh:
         nfs_free_fhandle(mntfh);
         kfree(data);
-        return error;
+        return mntroot;
 
 out_err_nosb:
         nfs_free_server(server);
@@ -2367,6 +2395,7 @@ out_err_nosb:
 
 error_splat_root:
         dput(mntroot);
+        mntroot = ERR_PTR(error);
 error_splat_super:
         if (server && !s->s_root)
                 bdi_unregister(&server->backing_dev_info);
@@ -2450,7 +2479,7 @@ nfs_xdev_mount(struct file_system_type *fs_type, int flags,
                 nfs_fscache_get_super_cookie(s, NULL, data);
         }
 
-        mntroot = nfs_get_root(s, data->fh);
+        mntroot = nfs_get_root(s, data->fh, dev_name);
         if (IS_ERR(mntroot)) {
                 error = PTR_ERR(mntroot);
                 goto error_splat_super;
@@ -2718,7 +2747,7 @@ nfs4_remote_mount(struct file_system_type *fs_type, int flags,
                         s, data ? data->fscache_uniq : NULL, NULL);
         }
 
-        mntroot = nfs4_get_root(s, mntfh);
+        mntroot = nfs4_get_root(s, mntfh, dev_name);
         if (IS_ERR(mntroot)) {
                 error = PTR_ERR(mntroot);
                 goto error_splat_super;
@@ -2771,27 +2800,6 @@ static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
         return root_mnt;
 }
 
-static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
-{
-        char *page = (char *) __get_free_page(GFP_KERNEL);
-        char *devname, *tmp;
-
-        if (page == NULL)
-                return;
-        devname = nfs_path(path->mnt->mnt_devname,
-                        path->mnt->mnt_root, path->dentry,
-                        page, PAGE_SIZE);
-        if (IS_ERR(devname))
-                goto out_freepage;
-        tmp = kstrdup(devname, GFP_KERNEL);
-        if (tmp == NULL)
-                goto out_freepage;
-        kfree(mnt->mnt_devname);
-        mnt->mnt_devname = tmp;
-out_freepage:
-        free_page((unsigned long)page);
-}
-
 struct nfs_referral_count {
         struct list_head list;
         const struct task_struct *task;
@@ -2858,17 +2866,18 @@ static void nfs_referral_loop_unprotect(void)
         kfree(p);
 }
 
-static int nfs_follow_remote_path(struct vfsmount *root_mnt,
-                const char *export_path, struct vfsmount *mnt_target)
+static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
+                const char *export_path)
 {
         struct nameidata *nd = NULL;
         struct mnt_namespace *ns_private;
         struct super_block *s;
+        struct dentry *dentry;
         int ret;
 
         nd = kmalloc(sizeof(*nd), GFP_KERNEL);
         if (nd == NULL)
-                return -ENOMEM;
+                return ERR_PTR(-ENOMEM);
 
         ns_private = create_mnt_ns(root_mnt);
         ret = PTR_ERR(ns_private);
@@ -2890,32 +2899,27 @@ static int nfs_follow_remote_path(struct vfsmount *root_mnt,
 
         s = nd->path.mnt->mnt_sb;
         atomic_inc(&s->s_active);
-        mnt_target->mnt_sb = s;
-        mnt_target->mnt_root = dget(nd->path.dentry);
-
-        /* Correct the device pathname */
-        nfs_fix_devname(&nd->path, mnt_target);
+        dentry = dget(nd->path.dentry);
 
         path_put(&nd->path);
         kfree(nd);
         down_write(&s->s_umount);
-        return 0;
+        return dentry;
 out_put_mnt_ns:
         put_mnt_ns(ns_private);
 out_mntput:
         mntput(root_mnt);
 out_err:
         kfree(nd);
-        return ret;
+        return ERR_PTR(ret);
 }
 
-static int nfs4_try_mount(int flags, const char *dev_name,
-                         struct nfs_parsed_mount_data *data,
-                         struct vfsmount *mnt)
+static struct dentry *nfs4_try_mount(int flags, const char *dev_name,
+                         struct nfs_parsed_mount_data *data)
 {
         char *export_path;
         struct vfsmount *root_mnt;
-        int error;
+        struct dentry *res;
 
         dfprintk(MOUNT, "--> nfs4_try_mount()\n");
 
@@ -2925,26 +2929,25 @@ static int nfs4_try_mount(int flags, const char *dev_name,
                         data->nfs_server.hostname);
         data->nfs_server.export_path = export_path;
 
-        error = PTR_ERR(root_mnt);
-        if (IS_ERR(root_mnt))
-                goto out;
+        res = ERR_CAST(root_mnt);
+        if (!IS_ERR(root_mnt))
+                res = nfs_follow_remote_path(root_mnt, export_path);
 
-        error = nfs_follow_remote_path(root_mnt, export_path, mnt);
-
-out:
-        dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
-                        error != 0 ? " [error]" : "");
-        return error;
+        dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
+                        IS_ERR(res) ? PTR_ERR(res) : 0,
+                        IS_ERR(res) ? " [error]" : "");
+        return res;
 }
 
 /*
  * Get the superblock for an NFS4 mountpoint
  */
-static int nfs4_get_sb(struct file_system_type *fs_type,
-        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
+static struct dentry *nfs4_mount(struct file_system_type *fs_type,
+        int flags, const char *dev_name, void *raw_data)
 {
         struct nfs_parsed_mount_data *data;
         int error = -ENOMEM;
+        struct dentry *res = ERR_PTR(-ENOMEM);
 
         data = nfs_alloc_parsed_mount_data(4);
         if (data == NULL)
@@ -2952,10 +2955,14 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
 
         /* Validate the mount data */
         error = nfs4_validate_mount_data(raw_data, data, dev_name);
-        if (error < 0)
+        if (error < 0) {
+                res = ERR_PTR(error);
                 goto out;
+        }
 
-        error = nfs4_try_mount(flags, dev_name, data, mnt);
+        res = nfs4_try_mount(flags, dev_name, data);
+        if (IS_ERR(res))
+                error = PTR_ERR(res);
 
 out:
         kfree(data->client_address);
@@ -2964,9 +2971,9 @@ out:
         kfree(data->fscache_uniq);
 out_free_data:
         kfree(data);
-        dprintk("<-- nfs4_get_sb() = %d%s\n", error,
+        dprintk("<-- nfs4_mount() = %d%s\n", error,
                         error != 0 ? " [error]" : "");
-        return error;
+        return res;
 }
 
 static void nfs4_kill_super(struct super_block *sb)
@@ -3033,7 +3040,7 @@ nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
                 nfs_fscache_get_super_cookie(s, NULL, data);
         }
 
-        mntroot = nfs4_get_root(s, data->fh);
+        mntroot = nfs4_get_root(s, data->fh, dev_name);
         if (IS_ERR(mntroot)) {
                 error = PTR_ERR(mntroot);
                 goto error_splat_super;
@@ -3120,7 +3127,7 @@ nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
                 nfs_fscache_get_super_cookie(s, NULL, data);
         }
 
-        mntroot = nfs4_get_root(s, mntfh);
+        mntroot = nfs4_get_root(s, mntfh, dev_name);
         if (IS_ERR(mntroot)) {
                 error = PTR_ERR(mntroot);
                 goto error_splat_super;
@@ -3160,16 +3167,15 @@ error_splat_bdi:
 /*
  * Create an NFS4 server record on referral traversal
  */
-static int nfs4_referral_get_sb(struct file_system_type *fs_type,
-                int flags, const char *dev_name, void *raw_data,
-                struct vfsmount *mnt)
+static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
+                int flags, const char *dev_name, void *raw_data)
 {
         struct nfs_clone_mount *data = raw_data;
         char *export_path;
         struct vfsmount *root_mnt;
-        int error;
+        struct dentry *res;
 
-        dprintk("--> nfs4_referral_get_sb()\n");
+        dprintk("--> nfs4_referral_mount()\n");
 
         export_path = data->mnt_path;
         data->mnt_path = "/";
@@ -3178,15 +3184,13 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type,
                         flags, data, data->hostname);
         data->mnt_path = export_path;
 
-        error = PTR_ERR(root_mnt);
-        if (IS_ERR(root_mnt))
-                goto out;
-
-        error = nfs_follow_remote_path(root_mnt, export_path, mnt);
-out:
-        dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
-                        error != 0 ? " [error]" : "");
-        return error;
+        res = ERR_CAST(root_mnt);
+        if (!IS_ERR(root_mnt))
+                res = nfs_follow_remote_path(root_mnt, export_path);
+        dprintk("<-- nfs4_referral_mount() = %ld%s\n",
+                        IS_ERR(res) ? PTR_ERR(res) : 0,
+                        IS_ERR(res) ? " [error]" : "");
+        return res;
 }
 
 #endif /* CONFIG_NFS_V4 */
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 6481d537d69d..8d6864c2a5fa 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -148,6 +148,7 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
         alias = d_lookup(parent, &data->args.name);
         if (alias != NULL) {
                 int ret = 0;
+                void *devname_garbage = NULL;
 
                 /*
                  * Hey, we raced with lookup... See if we need to transfer
@@ -157,6 +158,7 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
                 spin_lock(&alias->d_lock);
                 if (alias->d_inode != NULL &&
                     !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
+                        devname_garbage = alias->d_fsdata;
                         alias->d_fsdata = data;
                         alias->d_flags |= DCACHE_NFSFS_RENAMED;
                         ret = 1;
@@ -164,6 +166,13 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
                 spin_unlock(&alias->d_lock);
                 nfs_dec_sillycount(dir);
                 dput(alias);
+                /*
+                 * If we'd displaced old cached devname, free it.  At that
+                 * point dentry is definitely not a root, so we won't need
+                 * that anymore.
+                 */
+                if (devname_garbage)
+                        kfree(devname_garbage);
                 return ret;
         }
         data->dir = igrab(dir);
@@ -252,6 +261,7 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
 {
         struct nfs_unlinkdata *data;
         int status = -ENOMEM;
+        void *devname_garbage = NULL;
 
         data = kzalloc(sizeof(*data), GFP_KERNEL);
         if (data == NULL)
@@ -269,8 +279,16 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
         if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
                 goto out_unlock;
         dentry->d_flags |= DCACHE_NFSFS_RENAMED;
+        devname_garbage = dentry->d_fsdata;
         dentry->d_fsdata = data;
         spin_unlock(&dentry->d_lock);
+        /*
+         * If we'd displaced old cached devname, free it.  At that
+         * point dentry is definitely not a root, so we won't need
+         * that anymore.
+         */
+        if (devname_garbage)
+                kfree(devname_garbage);
         return 0;
 out_unlock:
         spin_unlock(&dentry->d_lock);
@@ -299,6 +317,7 @@ nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
         if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
                 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
                 data = dentry->d_fsdata;
+                dentry->d_fsdata = NULL;
         }
         spin_unlock(&dentry->d_lock);
 
@@ -315,6 +334,7 @@ nfs_cancel_async_unlink(struct dentry *dentry)
                 struct nfs_unlinkdata *data = dentry->d_fsdata;
 
                 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+                dentry->d_fsdata = NULL;
                 spin_unlock(&dentry->d_lock);
                 nfs_free_unlinkdata(data);
                 return;