--- /dev/null
+From c02d7adf8c5429727a98bad1d039bccad4c61c50 Mon Sep 17 00:00:00 2001
+From: Trond Myklebust <Trond.Myklebust@netapp.com>
+Date: Mon, 22 Jun 2009 15:09:14 -0400
+Subject: [PATCH 3/5] NFSv4: Replace nfs4_path_walk() with VFS path lookup in a private namespace
+
+As noted in the previous patch, the NFSv4 client mount code currently
+has several limitations. If the mount path contains symlinks, or
+referrals, or even if it just contains a '..', then the client code in
+nfs4_path_walk() will fail with an error.
+
+This patch replaces the nfs4_path_walk()-based lookup with a helper
+function that sets up a private namespace to represent the namespace on the
+server, then uses the ordinary VFS and NFS path lookup code to walk down the
+mount path in that namespace.
+
+Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Acked-by: NeilBrown <neilb@suse.de>
+---
+ fs/nfs/super.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
+ 1 file changed, 156 insertions(+), 20 deletions(-)
+
+--- linux-2.6.27-SLE11_BRANCH.orig/fs/nfs/super.c
++++ linux-2.6.27-SLE11_BRANCH/fs/nfs/super.c
+@@ -42,6 +42,8 @@
+ #include <linux/smp_lock.h>
+ #include <linux/seq_file.h>
+ #include <linux/mount.h>
++#include <linux/mnt_namespace.h>
++#include <linux/namei.h>
+ #include <linux/nfs_idmap.h>
+ #include <linux/vfs.h>
+ #include <linux/inet.h>
+@@ -244,10 +246,14 @@ static const struct super_operations nfs
+ #ifdef CONFIG_NFS_V4
+ static int nfs4_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
++static int nfs4_remote_get_sb(struct file_system_type *fs_type,
++ int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
+ static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
+ 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 int nfs4_remote_referral_get_sb(struct file_system_type *fs_type,
++ int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
+ static void nfs4_kill_super(struct super_block *sb);
+
+ static struct file_system_type nfs4_fs_type = {
+@@ -258,6 +264,14 @@ static struct file_system_type nfs4_fs_t
+ .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+ };
+
++static struct file_system_type nfs4_remote_fs_type = {
++ .owner = THIS_MODULE,
++ .name = "nfs4",
++ .get_sb = nfs4_remote_get_sb,
++ .kill_sb = nfs4_kill_super,
++ .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
++};
++
+ struct file_system_type nfs4_xdev_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "nfs4",
+@@ -266,6 +280,14 @@ struct file_system_type nfs4_xdev_fs_typ
+ .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+ };
+
++static struct file_system_type nfs4_remote_referral_fs_type = {
++ .owner = THIS_MODULE,
++ .name = "nfs4",
++ .get_sb = nfs4_remote_referral_get_sb,
++ .kill_sb = nfs4_kill_super,
++ .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
++};
++
+ struct file_system_type nfs4_referral_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "nfs4",
+@@ -2294,12 +2316,12 @@ out_no_client_address:
+ }
+
+ /*
+- * Get the superblock for an NFS4 mountpoint
++ * Get the superblock for the NFS4 root partition
+ */
+-static int nfs4_get_sb(struct file_system_type *fs_type,
++static int nfs4_remote_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
+ {
+- struct nfs_parsed_mount_data *data;
++ struct nfs_parsed_mount_data *data = raw_data;
+ struct super_block *s;
+ struct nfs_server *server;
+ struct nfs_fh *mntfh;
+@@ -2310,18 +2332,12 @@ static int nfs4_get_sb(struct file_syste
+ };
+ int error = -ENOMEM;
+
+- data = kzalloc(sizeof(*data), GFP_KERNEL);
+ mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
+ if (data == NULL || mntfh == NULL)
+ goto out_free_fh;
+
+ security_init_mnt_opts(&data->lsm_opts);
+
+- /* Validate the mount data */
+- error = nfs4_validate_mount_data(raw_data, data, dev_name);
+- if (error < 0)
+- goto out;
+-
+ /* Get a volume representation */
+ server = nfs4_create_server(data, mntfh);
+ if (IS_ERR(server)) {
+@@ -2334,7 +2350,7 @@ static int nfs4_get_sb(struct file_syste
+ compare_super = NULL;
+
+ /* 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);
++ s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
+ if (IS_ERR(s)) {
+ error = PTR_ERR(s);
+ goto out_free;
+@@ -2370,13 +2386,9 @@ static int nfs4_get_sb(struct file_syste
+ error = 0;
+
+ out:
+- kfree(data->client_address);
+- kfree(data->nfs_server.export_path);
+- kfree(data->nfs_server.hostname);
+ security_free_mnt_opts(&data->lsm_opts);
+ out_free_fh:
+ kfree(mntfh);
+- kfree(data);
+ return error;
+
+ out_free:
+@@ -2391,6 +2403,101 @@ error_splat_super:
+ goto out;
+ }
+
++static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
++ int flags, void *data, const char *hostname)
++{
++ struct vfsmount *root_mnt;
++ char *root_devname;
++ size_t len;
++
++ len = strlen(hostname) + 3;
++ root_devname = kmalloc(len, GFP_KERNEL);
++ if (root_devname == NULL)
++ return ERR_PTR(-ENOMEM);
++ snprintf(root_devname, len, "%s:/", hostname);
++ root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
++ kfree(root_devname);
++ return root_mnt;
++}
++
++static int nfs_follow_remote_path(struct vfsmount *root_mnt,
++ const char *export_path, struct vfsmount *mnt_target)
++{
++ struct mnt_namespace *ns_private;
++ struct nameidata nd;
++ struct super_block *s;
++ int ret;
++
++ ns_private = create_mnt_ns(root_mnt);
++ ret = PTR_ERR(ns_private);
++ if (IS_ERR(ns_private))
++ goto out_mntput;
++
++ ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
++ export_path, LOOKUP_FOLLOW, &nd);
++
++ put_mnt_ns(ns_private);
++
++ if (ret != 0)
++ goto out_err;
++
++ s = nd.path.mnt->mnt_sb;
++ atomic_inc(&s->s_active);
++ mnt_target->mnt_sb = s;
++ mnt_target->mnt_root = dget(nd.path.dentry);
++
++ path_put(&nd.path);
++ down_write(&s->s_umount);
++ return 0;
++out_mntput:
++ mntput(root_mnt);
++out_err:
++ return ret;
++}
++
++/*
++ * 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)
++{
++ struct nfs_parsed_mount_data *data;
++ char *export_path;
++ struct vfsmount *root_mnt;
++ int error = -ENOMEM;
++
++ data = kzalloc(sizeof(*data), GFP_KERNEL);
++ if (data == NULL)
++ goto out_free_data;
++
++ /* Validate the mount data */
++ error = nfs4_validate_mount_data(raw_data, data, dev_name);
++ if (error < 0)
++ goto out;
++
++ export_path = data->nfs_server.export_path;
++ data->nfs_server.export_path = "/";
++ root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
++ data->nfs_server.hostname);
++ data->nfs_server.export_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:
++ kfree(data->client_address);
++ kfree(data->nfs_server.export_path);
++ kfree(data->nfs_server.hostname);
++out_free_data:
++ kfree(data);
++ dprintk("<-- nfs4_get_sb() = %d%s\n", error,
++ error != 0 ? " [error]" : "");
++ return error;
++}
++
+ static void nfs4_kill_super(struct super_block *sb)
+ {
+ struct nfs_server *server = NFS_SB(sb);
+@@ -2486,12 +2593,9 @@ error_splat_super:
+ return error;
+ }
+
+-/*
+- * 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 int nfs4_remote_referral_get_sb(struct file_system_type *fs_type,
++ int flags, const char *dev_name, void *raw_data,
++ struct vfsmount *mnt)
+ {
+ struct nfs_clone_mount *data = raw_data;
+ struct super_block *s;
+@@ -2571,4 +2675,36 @@ error_splat_super:
+ return error;
+ }
+
++/*
++ * 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)
++{
++ struct nfs_clone_mount *data = raw_data;
++ char *export_path;
++ struct vfsmount *root_mnt;
++ int error;
++
++ dprintk("--> nfs4_referral_get_sb()\n");
++
++ export_path = data->mnt_path;
++ data->mnt_path = "/";
++
++ root_mnt = nfs_do_root_mount(&nfs4_remote_referral_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;
++}
++
+ #endif /* CONFIG_NFS_V4 */
projects / people / teissler / ipfire-2.x.git / blobdiff