forked from Minki/linux
90 lines
2.2 KiB
C
90 lines
2.2 KiB
C
/*
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* linux/fs/nfs/namespace.c
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*
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* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
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*
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* NFS namespace
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*/
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#include <linux/config.h>
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#include <linux/dcache.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/nfs_fs.h>
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#include <linux/string.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/vfs.h>
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#define NFSDBG_FACILITY NFSDBG_VFS
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/*
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* nfs_follow_mountpoint - handle crossing a mountpoint on the server
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* @dentry - dentry of mountpoint
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* @nd - nameidata info
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*
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* When we encounter a mountpoint on the server, we want to set up
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* a mountpoint on the client too, to prevent inode numbers from
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* colliding, and to allow "df" to work properly.
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* On NFSv4, we also want to allow for the fact that different
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* filesystems may be migrated to different servers in a failover
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* situation, and that different filesystems may want to use
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* different security flavours.
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*/
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static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
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{
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struct vfsmount *mnt;
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struct nfs_server *server = NFS_SERVER(dentry->d_inode);
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struct dentry *parent;
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struct nfs_fh fh;
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struct nfs_fattr fattr;
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int err;
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BUG_ON(IS_ROOT(dentry));
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dprintk("%s: enter\n", __FUNCTION__);
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dput(nd->dentry);
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nd->dentry = dget(dentry);
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if (d_mountpoint(nd->dentry))
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goto out_follow;
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/* Look it up again */
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parent = dget_parent(nd->dentry);
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err = server->rpc_ops->lookup(parent->d_inode, &nd->dentry->d_name, &fh, &fattr);
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dput(parent);
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if (err != 0)
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goto out_err;
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mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr);
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err = PTR_ERR(mnt);
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if (IS_ERR(mnt))
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goto out_err;
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mntget(mnt);
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err = do_add_mount(mnt, nd, nd->mnt->mnt_flags, NULL);
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if (err < 0) {
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mntput(mnt);
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if (err == -EBUSY)
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goto out_follow;
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goto out_err;
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}
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mntput(nd->mnt);
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dput(nd->dentry);
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nd->mnt = mnt;
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nd->dentry = dget(mnt->mnt_root);
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out:
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dprintk("%s: done, returned %d\n", __FUNCTION__, err);
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return ERR_PTR(err);
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out_err:
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path_release(nd);
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goto out;
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out_follow:
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while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
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;
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err = 0;
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goto out;
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}
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struct inode_operations nfs_mountpoint_inode_operations = {
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.follow_link = nfs_follow_mountpoint,
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.getattr = nfs_getattr,
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};
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