Commit 3cc55f44 authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Chuck Lever
Browse files

nfs: use change attribute for NFS re-exports 



When exporting NFS, we may as well use the real change attribute
returned by the original server instead of faking up a change attribute
from the ctime.

Note we can't do that by setting I_VERSION--that would also turn on the
logic in iversion.h which treats the lower bit specially, and that
doesn't make sense for NFS.

So instead we define a new export operation for filesystems like NFS
that want to manage the change attribute themselves.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 02591f9f

fs/nfs/export.c

+18 −0
Original line number Diff line number Diff line
@@ -167,10 +167,28 @@ nfs_get_parent(struct dentry *dentry) 
	return parent;

}



static u64 nfs_fetch_iversion(struct inode *inode)

{

	struct nfs_server *server = NFS_SERVER(inode);



	/* Is this the right call?: */

	nfs_revalidate_inode(server, inode);

	/*

	 * Also, note we're ignoring any returned error.  That seems to be

	 * the practice for cache consistency information elsewhere in

	 * the server, but I'm not sure why.

	 */

	if (server->nfs_client->rpc_ops->version >= 4)

		return inode_peek_iversion_raw(inode);

	else

		return time_to_chattr(&inode->i_ctime);

}



const struct export_operations nfs_export_ops = {

	.encode_fh = nfs_encode_fh,

	.fh_to_dentry = nfs_fh_to_dentry,

	.get_parent = nfs_get_parent,

	.fetch_iversion = nfs_fetch_iversion,

	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|

		EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS|

		EXPORT_OP_NOATOMIC_ATTR,

fs/nfsd/nfsfh.h

+4 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/sunrpc/svc.h>

#include <uapi/linux/nfsd/nfsfh.h>

#include <linux/iversion.h>

#include <linux/exportfs.h>



static inline __u32 ino_t_to_u32(ino_t ino)

{
@@ -264,7 +265,9 @@ fh_clear_wcc(struct svc_fh *fhp) 
static inline u64 nfsd4_change_attribute(struct kstat *stat,

					 struct inode *inode)

{

	if (IS_I_VERSION(inode)) {

	if (inode->i_sb->s_export_op->fetch_iversion)

		return inode->i_sb->s_export_op->fetch_iversion(inode);

	else if (IS_I_VERSION(inode)) {

		u64 chattr;



		chattr =  stat->ctime.tv_sec;

include/linux/exportfs.h

+1 −0
Original line number Diff line number Diff line
@@ -213,6 +213,7 @@ struct export_operations { 
			  bool write, u32 *device_generation);

	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,

			     int nr_iomaps, struct iattr *iattr);

	u64 (*fetch_iversion)(struct inode *);

#define	EXPORT_OP_NOWCC			(0x1) /* don't collect v3 wcc data */

#define	EXPORT_OP_NOSUBTREECHK		(0x2) /* no subtree checking */

#define	EXPORT_OP_CLOSE_BEFORE_UNLINK	(0x4) /* close files before unlink */