* 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;
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:
void __exit exit_nfs_v4(void)
{
+ unregister_filesystem(&nfs4_fs_type);
nfs4_unregister_sysctl();
nfs_idmap_quit();
}
{ Opt_vers_err, NULL }
};
-struct nfs_mount_info {
- void (*fill_super)(struct super_block *, struct nfs_mount_info *);
- int (*set_security)(struct super_block *, struct dentry *, struct nfs_mount_info *);
- struct nfs_parsed_mount_data *parsed;
- struct nfs_clone_mount *cloned;
- struct nfs_fh *mntfh;
-};
-
-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 dentry *);
-static int nfs_show_devname(struct seq_file *, struct dentry *);
-static int nfs_show_path(struct seq_file *, struct dentry *);
-static int nfs_show_stats(struct seq_file *, struct dentry *);
-static struct dentry *nfs_fs_mount_common(struct file_system_type *,
- struct nfs_server *, int, const char *, struct nfs_mount_info *);
-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 *);
-static void nfs_kill_super(struct super_block *);
-static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
static struct file_system_type nfs_fs_type = {
.owner = THIS_MODULE,
static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *);
static int nfs4_validate_mount_data(void *options,
struct nfs_parsed_mount_data *args, const char *dev_name);
-static struct dentry *nfs4_try_mount(int flags, const char *dev_name,
- struct nfs_mount_info *mount_info);
-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,
-};
#endif
static struct shrinker acl_shrinker = {
ret = nfs_register_sysctl();
if (ret < 0)
goto error_1;
-#ifdef CONFIG_NFS_V4
- ret = register_filesystem(&nfs4_fs_type);
- if (ret < 0)
- goto error_2;
-#endif
register_shrinker(&acl_shrinker);
return 0;
-#ifdef CONFIG_NFS_V4
-error_2:
- nfs_unregister_sysctl();
-#endif
error_1:
unregister_filesystem(&nfs_fs_type);
error_0:
void __exit unregister_nfs_fs(void)
{
unregister_shrinker(&acl_shrinker);
-#ifdef CONFIG_NFS_V4
- unregister_filesystem(&nfs4_fs_type);
-#endif
nfs_unregister_sysctl();
unregister_filesystem(&nfs_fs_type);
}
/*
* Deliver file system statistics to userspace
*/
-static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct nfs_server *server = NFS_SB(dentry->d_sb);
unsigned char blockbits;
/*
* Describe the mount options on this VFS mountpoint
*/
-static int nfs_show_options(struct seq_file *m, struct dentry *root)
+int nfs_show_options(struct seq_file *m, struct dentry *root)
{
struct nfs_server *nfss = NFS_SB(root->d_sb);
}
#endif
-static int nfs_show_devname(struct seq_file *m, struct dentry *root)
+int nfs_show_devname(struct seq_file *m, struct dentry *root)
{
char *page = (char *) __get_free_page(GFP_KERNEL);
char *devname, *dummy;
return err;
}
-static int nfs_show_path(struct seq_file *m, struct dentry *dentry)
+int nfs_show_path(struct seq_file *m, struct dentry *dentry)
{
seq_puts(m, "/");
return 0;
/*
* Present statistical information for this VFS mountpoint
*/
-static int nfs_show_stats(struct seq_file *m, struct dentry *root)
+int nfs_show_stats(struct seq_file *m, struct dentry *root)
{
int i, cpu;
struct nfs_server *nfss = NFS_SB(root->d_sb);
* Begin unmount by attempting to remove all automounted mountpoints we added
* in response to xdev traversals and referrals
*/
-static void nfs_umount_begin(struct super_block *sb)
+void nfs_umount_begin(struct super_block *sb)
{
struct nfs_server *server;
struct rpc_clnt *rpc;
return 0;
}
-static int
+int
nfs_remount(struct super_block *sb, int *flags, char *raw_data)
{
int error;
/*
* Initialise the common bits of the superblock
*/
-static inline void nfs_initialise_sb(struct super_block *sb)
+inline void nfs_initialise_sb(struct super_block *sb)
{
struct nfs_server *server = NFS_SB(sb);
/*
* Finish setting up an NFS2/3 superblock
*/
-static void nfs_fill_super(struct super_block *sb,
- struct nfs_mount_info *mount_info)
+void nfs_fill_super(struct super_block *sb, struct nfs_mount_info *mount_info)
{
struct nfs_parsed_mount_data *data = mount_info->parsed;
struct nfs_server *server = NFS_SB(sb);
/*
* Finish setting up a cloned NFS2/3/4 superblock
*/
-static void nfs_clone_super(struct super_block *sb,
- struct nfs_mount_info *mount_info)
+void nfs_clone_super(struct super_block *sb, struct nfs_mount_info *mount_info)
{
const struct super_block *old_sb = mount_info->cloned->sb;
struct nfs_server *server = NFS_SB(sb);
return bdi_register_dev(&server->backing_dev_info, server->s_dev);
}
-static int nfs_set_sb_security(struct super_block *s, struct dentry *mntroot,
- struct nfs_mount_info *mount_info)
+int nfs_set_sb_security(struct super_block *s, struct dentry *mntroot,
+ struct nfs_mount_info *mount_info)
{
return security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts);
}
-static int nfs_clone_sb_security(struct super_block *s, struct dentry *mntroot,
- struct nfs_mount_info *mount_info)
+int nfs_clone_sb_security(struct super_block *s, struct dentry *mntroot,
+ struct nfs_mount_info *mount_info)
{
/* clone any lsm security options from the parent to the new sb */
security_sb_clone_mnt_opts(mount_info->cloned->sb, s);
return 0;
}
-static struct dentry *nfs_fs_mount_common(struct file_system_type *fs_type,
- struct nfs_server *server,
- int flags, const char *dev_name,
- struct nfs_mount_info *mount_info)
+struct dentry *nfs_fs_mount_common(struct file_system_type *fs_type,
+ struct nfs_server *server,
+ int flags, const char *dev_name,
+ struct nfs_mount_info *mount_info)
{
struct super_block *s;
struct dentry *mntroot = ERR_PTR(-ENOMEM);
goto out;
}
-static struct dentry *nfs_fs_mount(struct file_system_type *fs_type,
+struct dentry *nfs_fs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data)
{
struct nfs_mount_info mount_info = {
* Ensure that we unregister the bdi before kill_anon_super
* releases the device name
*/
-static void nfs_put_super(struct super_block *s)
+void nfs_put_super(struct super_block *s)
{
struct nfs_server *server = NFS_SB(s);
/*
* Destroy an NFS2/3 superblock
*/
-static void nfs_kill_super(struct super_block *s)
+void nfs_kill_super(struct super_block *s)
{
struct nfs_server *server = NFS_SB(s);
/*
* Clone an NFS2/3/4 server record on xdev traversal (FSID-change)
*/
-static struct dentry *
+struct dentry *
nfs_xdev_mount_common(struct file_system_type *fs_type, int flags,
const char *dev_name, struct nfs_mount_info *mount_info)
{
#ifdef CONFIG_NFS_V4
-/*
- * 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);
-}
-
static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
{
args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
return -EINVAL;
}
-/*
- * 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;
-}
-
-static 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;
-}
-
#endif /* CONFIG_NFS_V4 */
projects / linux-beck.git / commitdiff