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-rw-r--r--fs/nfs/namespace.c112
1 files changed, 111 insertions, 1 deletions
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 8ca44b7b25c3..19b98ca468eb 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -15,15 +15,64 @@
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
+#include "internal.h"
#define NFSDBG_FACILITY NFSDBG_VFS
-LIST_HEAD(nfs_automount_list);
static void nfs_expire_automounts(void *list);
+
+LIST_HEAD(nfs_automount_list);
static DECLARE_WORK(nfs_automount_task, nfs_expire_automounts, &nfs_automount_list);
int nfs_mountpoint_expiry_timeout = 500 * HZ;
/*
+ * nfs_path - reconstruct the path given an arbitrary dentry
+ * @base - arbitrary string to prepend to the 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.
+ *
+ * This is mainly for use in figuring out the path on the
+ * server side when automounting on top of an existing partition.
+ */
+char *nfs_path(const char *base, const struct dentry *dentry,
+ char *buffer, ssize_t buflen)
+{
+ char *end = buffer+buflen;
+ int namelen;
+
+ *--end = '\0';
+ buflen--;
+ spin_lock(&dcache_lock);
+ while (!IS_ROOT(dentry)) {
+ namelen = dentry->d_name.len;
+ buflen -= namelen + 1;
+ if (buflen < 0)
+ goto Elong;
+ end -= namelen;
+ memcpy(end, dentry->d_name.name, namelen);
+ *--end = '/';
+ dentry = dentry->d_parent;
+ }
+ spin_unlock(&dcache_lock);
+ namelen = strlen(base);
+ /* Strip off excess slashes in base string */
+ while (namelen > 0 && base[namelen - 1] == '/')
+ namelen--;
+ buflen -= namelen;
+ if (buflen < 0)
+ goto Elong;
+ end -= namelen;
+ memcpy(end, base, namelen);
+ return end;
+Elong:
+ return ERR_PTR(-ENAMETOOLONG);
+}
+
+/*
* nfs_follow_mountpoint - handle crossing a mountpoint on the server
* @dentry - dentry of mountpoint
* @nd - nameidata info
@@ -117,3 +166,64 @@ void nfs_release_automount_timer(void)
flush_scheduled_work();
}
}
+
+/*
+ * Clone a mountpoint of the appropriate type
+ */
+static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, char *devname,
+ struct nfs_clone_mount *mountdata)
+{
+#ifdef CONFIG_NFS_V4
+ struct vfsmount *mnt = NULL;
+ switch (server->rpc_ops->version) {
+ case 2:
+ case 3:
+ mnt = vfs_kern_mount(&clone_nfs_fs_type, 0, devname, mountdata);
+ break;
+ case 4:
+ mnt = vfs_kern_mount(&clone_nfs4_fs_type, 0, devname, mountdata);
+ }
+ return mnt;
+#else
+ return vfs_kern_mount(&clone_nfs_fs_type, 0, devname, mountdata);
+#endif
+}
+
+/**
+ * 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
+ *
+ */
+struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
+ const struct dentry *dentry, struct nfs_fh *fh,
+ struct nfs_fattr *fattr)
+{
+ struct nfs_clone_mount mountdata = {
+ .sb = mnt_parent->mnt_sb,
+ .dentry = dentry,
+ .fh = fh,
+ .fattr = fattr,
+ };
+ struct vfsmount *mnt = ERR_PTR(-ENOMEM);
+ char *page = (char *) __get_free_page(GFP_USER);
+ char *devname;
+
+ dprintk("%s: submounting on %s/%s\n", __FUNCTION__,
+ dentry->d_parent->d_name.name,
+ dentry->d_name.name);
+ if (page == NULL)
+ goto out;
+ devname = nfs_devname(mnt_parent, 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);
+free_page:
+ free_page((unsigned long)page);
+out:
+ dprintk("%s: done\n", __FUNCTION__);
+ return mnt;
+}