NFS: Use d_automount() rather than abusing follow_link() (36d43a43) · Commits · e / devices / android_kernel_fairphone_FP4

fs/nfs/dir.c

+3 −1

Original line number	Original line	Diff line number	Diff line
	@@ -970,7 +970,7 @@ int nfs_lookup_verify_inode(struct inode inode, struct nameidata nd)
	{		{
	struct nfs_server *server = NFS_SERVER(inode);		struct nfs_server *server = NFS_SERVER(inode);

	if (test_bit(NFS_INO_MOUNTPOINT, &NFS_I(inode)->flags))		if (IS_AUTOMOUNT(inode))
	return 0;		return 0;
	if (nd != NULL) {		if (nd != NULL) {
	/* VFS wants an on-the-wire revalidation */		/* VFS wants an on-the-wire revalidation */
	@@ -1173,6 +1173,7 @@ const struct dentry_operations nfs_dentry_operations = {
	.d_revalidate = nfs_lookup_revalidate,		.d_revalidate = nfs_lookup_revalidate,
	.d_delete = nfs_dentry_delete,		.d_delete = nfs_dentry_delete,
	.d_iput = nfs_dentry_iput,		.d_iput = nfs_dentry_iput,
			.d_automount = nfs_d_automount,
	};		};

	static struct dentry nfs_lookup(struct inode dir, struct dentry * dentry, struct nameidata *nd)		static struct dentry nfs_lookup(struct inode dir, struct dentry * dentry, struct nameidata *nd)
	@@ -1246,6 +1247,7 @@ const struct dentry_operations nfs4_dentry_operations = {
	.d_revalidate = nfs_open_revalidate,		.d_revalidate = nfs_open_revalidate,
	.d_delete = nfs_dentry_delete,		.d_delete = nfs_dentry_delete,
	.d_iput = nfs_dentry_iput,		.d_iput = nfs_dentry_iput,
			.d_automount = nfs_d_automount,
	};		};

	/*		/*

fs/nfs/inode.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -300,7 +300,7 @@ nfs_fhget(struct super_block sb, struct nfs_fh fh, struct nfs_fattr *fattr)
	else		else
	inode->i_op = &nfs_mountpoint_inode_operations;		inode->i_op = &nfs_mountpoint_inode_operations;
	inode->i_fop = NULL;		inode->i_fop = NULL;
	set_bit(NFS_INO_MOUNTPOINT, &nfsi->flags);		inode->i_flags \|= S_AUTOMOUNT;
	}		}
	} else if (S_ISLNK(inode->i_mode))		} else if (S_ISLNK(inode->i_mode))
	inode->i_op = &nfs_symlink_inode_operations;		inode->i_op = &nfs_symlink_inode_operations;
	@@ -1208,7 +1208,7 @@ static int nfs_update_inode(struct inode inode, struct nfs_fattr fattr)
	/* Update the fsid? */		/* Update the fsid? */
	if (S_ISDIR(inode->i_mode) && (fattr->valid & NFS_ATTR_FATTR_FSID) &&		if (S_ISDIR(inode->i_mode) && (fattr->valid & NFS_ATTR_FATTR_FSID) &&
	!nfs_fsid_equal(&server->fsid, &fattr->fsid) &&		!nfs_fsid_equal(&server->fsid, &fattr->fsid) &&
	!test_bit(NFS_INO_MOUNTPOINT, &nfsi->flags))		!IS_AUTOMOUNT(inode))
	server->fsid = fattr->fsid;		server->fsid = fattr->fsid;

	/*		/*

fs/nfs/internal.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -252,6 +252,7 @@ extern char nfs_path(const char base,
	const struct dentry *droot,		const struct dentry *droot,
	const struct dentry *dentry,		const struct dentry *dentry,
	char *buffer, ssize_t buflen);		char *buffer, ssize_t buflen);
			extern struct vfsmount nfs_d_automount(struct path path);

	/* getroot.c */		/* getroot.c */
	extern struct dentry nfs_get_root(struct super_block , struct nfs_fh *);		extern struct dentry nfs_get_root(struct super_block , struct nfs_fh *);

fs/nfs/namespace.c

+40 −44

Original line number	Original line	Diff line number	Diff line
	@@ -97,9 +97,8 @@ char nfs_path(const char base,
	}		}

	/*		/*
	* nfs_follow_mountpoint - handle crossing a mountpoint on the server		* nfs_d_automount - Handle crossing a mountpoint on the server
	* @dentry - dentry of mountpoint		* @path - The mountpoint
	* @nd - nameidata info
	*		*
	* When we encounter a mountpoint on the server, we want to set up		* When we encounter a mountpoint on the server, we want to set up
	* a mountpoint on the client too, to prevent inode numbers from		* a mountpoint on the client too, to prevent inode numbers from
	@@ -109,84 +108,81 @@ char nfs_path(const char base,
	* situation, and that different filesystems may want to use		* situation, and that different filesystems may want to use
	* different security flavours.		* different security flavours.
	*/		*/
	static void * nfs_follow_mountpoint(struct dentry dentry, struct nameidata nd)		struct vfsmount nfs_d_automount(struct path path)
	{		{
	struct vfsmount *mnt;		struct vfsmount *mnt;
	struct nfs_server *server = NFS_SERVER(dentry->d_inode);		struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
	struct dentry *parent;		struct dentry *parent;
	struct nfs_fh *fh = NULL;		struct nfs_fh *fh = NULL;
	struct nfs_fattr *fattr = NULL;		struct nfs_fattr *fattr = NULL;
	int err;		int err;

	dprintk("--> nfs_follow_mountpoint()\n");		dprintk("--> nfs_d_automount()\n");

	err = -ESTALE;		mnt = ERR_PTR(-ESTALE);
	if (IS_ROOT(dentry))		if (IS_ROOT(path->dentry))
	goto out_err;		goto out_nofree;

	err = -ENOMEM;		mnt = ERR_PTR(-ENOMEM);
	fh = nfs_alloc_fhandle();		fh = nfs_alloc_fhandle();
	fattr = nfs_alloc_fattr();		fattr = nfs_alloc_fattr();
	if (fh == NULL \|\| fattr == NULL)		if (fh == NULL \|\| fattr == NULL)
	goto out_err;		goto out;

	dprintk("%s: enter\n", __func__);		dprintk("%s: enter\n", __func__);
	dput(nd->path.dentry);
	nd->path.dentry = dget(dentry);

	/* Look it up again */		/* Look it up again to get its attributes */
	parent = dget_parent(nd->path.dentry);		parent = dget_parent(path->dentry);
	err = server->nfs_client->rpc_ops->lookup(parent->d_inode,		err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
	&nd->path.dentry->d_name,		&path->dentry->d_name,
	fh, fattr);		fh, fattr);
	dput(parent);		dput(parent);
	if (err != 0)		if (err != 0) {
	goto out_err;		mnt = ERR_PTR(err);
			goto out;
			}

	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)		if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
	mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry);		mnt = nfs_do_refmount(path->mnt, path->dentry);
	else		else
	mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, fh,		mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr);
	fattr);
	err = PTR_ERR(mnt);
	if (IS_ERR(mnt))		if (IS_ERR(mnt))
	goto out_err;		goto out;

	mntget(mnt);		mntget(mnt);
	err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags\|MNT_SHRINKABLE,		err = do_add_mount(mnt, path, path->mnt->mnt_flags \| MNT_SHRINKABLE,
	&nfs_automount_list);		&nfs_automount_list);
	if (err < 0) {		switch (err) {
			case 0:
			dprintk("%s: done, success\n", __func__);
			schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
			break;
			case -EBUSY:
			/* someone else made a mount here whilst we were busy */
			mntput(mnt);
			dprintk("%s: done, collision\n", __func__);
			mnt = NULL;
			break;
			default:
	mntput(mnt);		mntput(mnt);
	if (err == -EBUSY)		dprintk("%s: done, error %d\n", __func__, err);
	goto out_follow;		mnt = ERR_PTR(err);
	goto out_err;		break;
	}		}
	path_put(&nd->path);
	nd->path.mnt = mnt;
	nd->path.dentry = dget(mnt->mnt_root);
	schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
	out:		out:
	nfs_free_fattr(fattr);		nfs_free_fattr(fattr);
	nfs_free_fhandle(fh);		nfs_free_fhandle(fh);
	dprintk("%s: done, returned %d\n", __func__, err);		out_nofree:
			dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt);
	dprintk("<-- nfs_follow_mountpoint() = %d\n", err);		return mnt;
	return ERR_PTR(err);
	out_err:
	path_put(&nd->path);
	goto out;
	out_follow:
	err = follow_down(&nd->path, false);
	goto out;
	}		}

	const struct inode_operations nfs_mountpoint_inode_operations = {		const struct inode_operations nfs_mountpoint_inode_operations = {
	.follow_link = nfs_follow_mountpoint,
	.getattr = nfs_getattr,		.getattr = nfs_getattr,
	};		};

	const struct inode_operations nfs_referral_inode_operations = {		const struct inode_operations nfs_referral_inode_operations = {
	.follow_link = nfs_follow_mountpoint,
	};		};

	static void nfs_expire_automounts(struct work_struct *work)		static void nfs_expire_automounts(struct work_struct *work)

include/linux/nfs_fs.h

+0 −1

Original line number	Original line	Diff line number	Diff line
	@@ -215,7 +215,6 @@ struct nfs_inode {
	#define NFS_INO_ADVISE_RDPLUS (0) /* advise readdirplus */		#define NFS_INO_ADVISE_RDPLUS (0) /* advise readdirplus */
	#define NFS_INO_STALE (1) /* possible stale inode */		#define NFS_INO_STALE (1) /* possible stale inode */
	#define NFS_INO_ACL_LRU_SET (2) /* Inode is on the LRU list */		#define NFS_INO_ACL_LRU_SET (2) /* Inode is on the LRU list */
	#define NFS_INO_MOUNTPOINT (3) /* inode is remote mountpoint */
	#define NFS_INO_FLUSHING (4) /* inode is flushing out data */		#define NFS_INO_FLUSHING (4) /* inode is flushing out data */
	#define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */		#define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */
	#define NFS_INO_FSCACHE_LOCK (6) /* FS-Cache cookie management lock */		#define NFS_INO_FSCACHE_LOCK (6) /* FS-Cache cookie management lock */