forked from Minki/linux
6b97fd3da1
Respond to a moved error on NFS lookup by setting up the referral. Note: We don't actually follow the referral during lookup/getattr, but later when we detect fsid mismatch in inode revalidation (similar to the processing done for cloning submounts). Referrals will have fake attributes until they are actually followed or traversed. Signed-off-by: Manoj Naik <manoj@almaden.ibm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
120 lines
3.1 KiB
C
120 lines
3.1 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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LIST_HEAD(nfs_automount_list);
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static void nfs_expire_automounts(void *list);
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static DECLARE_WORK(nfs_automount_task, nfs_expire_automounts, &nfs_automount_list);
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int nfs_mountpoint_expiry_timeout = 500 * HZ;
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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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if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL)
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mnt = nfs_do_refmount(nd->mnt, nd->dentry);
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else
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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|MNT_SHRINKABLE, &nfs_automount_list);
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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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schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
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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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struct inode_operations nfs_referral_inode_operations = {
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.follow_link = nfs_follow_mountpoint,
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};
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static void nfs_expire_automounts(void *data)
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{
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struct list_head *list = (struct list_head *)data;
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mark_mounts_for_expiry(list);
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if (!list_empty(list))
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schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
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}
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void nfs_release_automount_timer(void)
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{
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if (list_empty(&nfs_automount_list)) {
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cancel_delayed_work(&nfs_automount_task);
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flush_scheduled_work();
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}
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}
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