NFS: Split out the NFS v4 filesystem types
This allows me to move the v4 mounting and unmounting functions out of
the generic client and into a file that is only compiled when CONFIG_NFS_V4
is enabled.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c
index 70c394e..2af2691 100644
--- a/fs/nfs/nfs4super.c
+++ b/fs/nfs/nfs4super.c
@@ -2,10 +2,331 @@
* Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
*/
#include <linux/init.h>
+#include <linux/module.h>
#include <linux/nfs_idmap.h>
+#include <linux/nfs4_mount.h>
#include <linux/nfs_fs.h>
+#include "internal.h"
#include "nfs4_fs.h"
+#define NFSDBG_FACILITY NFSDBG_VFS
+
+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 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 struct file_system_type nfs4_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "nfs4",
+ .mount = nfs_fs_mount,
+ .kill_sb = nfs_kill_super,
+ .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",
+ .mount = nfs4_remote_mount,
+ .kill_sb = nfs_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",
+ .mount = nfs4_xdev_mount,
+ .kill_sb = nfs_kill_super,
+ .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",
+ .mount = nfs4_remote_referral_mount,
+ .kill_sb = nfs_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",
+ .mount = nfs4_referral_mount,
+ .kill_sb = nfs_kill_super,
+ .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+static const struct super_operations nfs4_sops = {
+ .alloc_inode = nfs_alloc_inode,
+ .destroy_inode = nfs_destroy_inode,
+ .write_inode = nfs4_write_inode,
+ .put_super = nfs_put_super,
+ .statfs = nfs_statfs,
+ .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,
+};
+
+/*
+ * Set up an NFS4 superblock
+ */
+static void nfs4_fill_super(struct super_block *sb,
+ struct nfs_mount_info *mount_info)
+{
+ sb->s_time_gran = 1;
+ sb->s_op = &nfs4_sops;
+ /*
+ * The VFS shouldn't apply the umask to mode bits. We will do
+ * so ourselves when necessary.
+ */
+ sb->s_flags |= MS_POSIXACL;
+ sb->s_xattr = nfs4_xattr_handlers;
+ nfs_initialise_sb(sb);
+}
+
+/*
+ * Get the superblock for the NFS4 root partition
+ */
+static struct dentry *
+nfs4_remote_mount(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *info)
+{
+ struct nfs_mount_info *mount_info = info;
+ struct nfs_server *server;
+ struct dentry *mntroot = ERR_PTR(-ENOMEM);
+
+ mount_info->fill_super = nfs4_fill_super;
+ mount_info->set_security = nfs_set_sb_security;
+
+ /* Get a volume representation */
+ server = nfs4_create_server(mount_info->parsed, mount_info->mntfh);
+ if (IS_ERR(server)) {
+ mntroot = ERR_CAST(server);
+ goto out;
+ }
+
+ mntroot = nfs_fs_mount_common(fs_type, server, flags, dev_name, mount_info);
+
+out:
+ return mntroot;
+}
+
+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) + 5;
+ root_devname = kmalloc(len, GFP_KERNEL);
+ if (root_devname == NULL)
+ return ERR_PTR(-ENOMEM);
+ /* Does hostname needs to be enclosed in brackets? */
+ if (strchr(hostname, ':'))
+ snprintf(root_devname, len, "[%s]:/", hostname);
+ else
+ snprintf(root_devname, len, "%s:/", hostname);
+ root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
+ kfree(root_devname);
+ return root_mnt;
+}
+
+struct nfs_referral_count {
+ struct list_head list;
+ const struct task_struct *task;
+ unsigned int referral_count;
+};
+
+static LIST_HEAD(nfs_referral_count_list);
+static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
+
+static struct nfs_referral_count *nfs_find_referral_count(void)
+{
+ struct nfs_referral_count *p;
+
+ list_for_each_entry(p, &nfs_referral_count_list, list) {
+ if (p->task == current)
+ return p;
+ }
+ return NULL;
+}
+
+#define NFS_MAX_NESTED_REFERRALS 2
+
+static int nfs_referral_loop_protect(void)
+{
+ struct nfs_referral_count *p, *new;
+ int ret = -ENOMEM;
+
+ new = kmalloc(sizeof(*new), GFP_KERNEL);
+ if (!new)
+ goto out;
+ new->task = current;
+ new->referral_count = 1;
+
+ ret = 0;
+ spin_lock(&nfs_referral_count_list_lock);
+ p = nfs_find_referral_count();
+ if (p != NULL) {
+ if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
+ ret = -ELOOP;
+ else
+ p->referral_count++;
+ } else {
+ list_add(&new->list, &nfs_referral_count_list);
+ new = NULL;
+ }
+ spin_unlock(&nfs_referral_count_list_lock);
+ kfree(new);
+out:
+ return ret;
+}
+
+static void nfs_referral_loop_unprotect(void)
+{
+ struct nfs_referral_count *p;
+
+ spin_lock(&nfs_referral_count_list_lock);
+ p = nfs_find_referral_count();
+ p->referral_count--;
+ if (p->referral_count == 0)
+ list_del(&p->list);
+ else
+ p = NULL;
+ spin_unlock(&nfs_referral_count_list_lock);
+ kfree(p);
+}
+
+static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
+ const char *export_path)
+{
+ struct dentry *dentry;
+ int err;
+
+ if (IS_ERR(root_mnt))
+ return ERR_CAST(root_mnt);
+
+ err = nfs_referral_loop_protect();
+ if (err) {
+ mntput(root_mnt);
+ return ERR_PTR(err);
+ }
+
+ dentry = mount_subtree(root_mnt, export_path);
+ nfs_referral_loop_unprotect();
+
+ return dentry;
+}
+
+struct dentry *nfs4_try_mount(int flags, const char *dev_name,
+ struct nfs_mount_info *mount_info)
+{
+ char *export_path;
+ struct vfsmount *root_mnt;
+ struct dentry *res;
+ struct nfs_parsed_mount_data *data = mount_info->parsed;
+
+ dfprintk(MOUNT, "--> nfs4_try_mount()\n");
+
+ mount_info->fill_super = nfs4_fill_super;
+
+ export_path = data->nfs_server.export_path;
+ data->nfs_server.export_path = "/";
+ root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
+ data->nfs_server.hostname);
+ data->nfs_server.export_path = export_path;
+
+ res = nfs_follow_remote_path(root_mnt, export_path);
+
+ dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
+ IS_ERR(res) ? PTR_ERR(res) : 0,
+ IS_ERR(res) ? " [error]" : "");
+ return res;
+}
+
+/*
+ * Clone an NFS4 server record on xdev traversal (FSID-change)
+ */
+static struct dentry *
+nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *raw_data)
+{
+ struct nfs_mount_info mount_info = {
+ .fill_super = nfs_clone_super,
+ .set_security = nfs_clone_sb_security,
+ .cloned = raw_data,
+ };
+ return nfs_xdev_mount_common(&nfs4_fs_type, flags, dev_name, &mount_info);
+}
+
+static struct dentry *
+nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *raw_data)
+{
+ struct nfs_mount_info mount_info = {
+ .fill_super = nfs4_fill_super,
+ .set_security = nfs_clone_sb_security,
+ .cloned = raw_data,
+ };
+ struct nfs_server *server;
+ struct dentry *mntroot = ERR_PTR(-ENOMEM);
+
+ dprintk("--> nfs4_referral_get_sb()\n");
+
+ mount_info.mntfh = nfs_alloc_fhandle();
+ if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
+ goto out;
+
+ /* create a new volume representation */
+ server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
+ if (IS_ERR(server)) {
+ mntroot = ERR_CAST(server);
+ goto out;
+ }
+
+ mntroot = nfs_fs_mount_common(&nfs4_fs_type, server, flags, dev_name, &mount_info);
+out:
+ nfs_free_fhandle(mount_info.mntfh);
+ return mntroot;
+}
+
+/*
+ * Create an NFS4 server record on referral traversal
+ */
+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;
+ struct dentry *res;
+
+ dprintk("--> nfs4_referral_mount()\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;
+
+ 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;
+}
+
+
int __init init_nfs_v4(void)
{
int err;
@@ -18,7 +339,13 @@
if (err)
goto out1;
+ err = register_filesystem(&nfs4_fs_type);
+ if (err < 0)
+ goto out2;
+
return 0;
+out2:
+ nfs4_unregister_sysctl();
out1:
nfs_idmap_quit();
out:
@@ -27,6 +354,7 @@
void __exit exit_nfs_v4(void)
{
+ unregister_filesystem(&nfs4_fs_type);
nfs4_unregister_sysctl();
nfs_idmap_quit();
}