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Commit c654b8a9 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd: support ext4 i_version 



ext4 supports a real NFSv4 change attribute, which is bumped whenever
the ctime would be updated, including times when two updates arrive
within a jiffy of each other.  (Note that although ext4 has space for
nanosecond-precision ctime, the real resolution is lower: it actually
uses jiffies as the time-source.)  This ensures clients will invalidate
their caches when they need to.

There is some fear that keeping the i_version up-to-date could have
performance drawbacks, so for now it's turned on only by a mount option.
We hope to do something better eventually.

Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Theodore Tso <tytso@mit.edu>
parent 3352d2c2

fs/nfsd/nfs3xdr.c

+1 −0
Original line number Diff line number Diff line
@@ -272,6 +272,7 @@ void fill_post_wcc(struct svc_fh *fhp) 


	err = vfs_getattr(fhp->fh_export->ex_path.mnt, fhp->fh_dentry,

			&fhp->fh_post_attr);

	fhp->fh_post_change = fhp->fh_dentry->d_inode->i_version;

	if (err)

		fhp->fh_post_saved = 0;

	else

fs/nfsd/nfs4xdr.c

+42 −21
Original line number Diff line number Diff line
@@ -1490,13 +1490,41 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp) 
	memcpy(p, ptr, nbytes);					\

	p += XDR_QUADLEN(nbytes);				\

}} while (0)

#define WRITECINFO(c)		do {				\

	*p++ = htonl(c.atomic);					\

	*p++ = htonl(c.before_ctime_sec);				\

	*p++ = htonl(c.before_ctime_nsec);				\

	*p++ = htonl(c.after_ctime_sec);				\

	*p++ = htonl(c.after_ctime_nsec);				\

} while (0)



static void write32(__be32 **p, u32 n)

{

	*(*p)++ = n;

}



static void write64(__be32 **p, u64 n)

{

	write32(p, (u32)(n >> 32));

	write32(p, (u32)n);

}



static void write_change(__be32 **p, struct kstat *stat, struct inode *inode)

{

	if (IS_I_VERSION(inode)) {

		write64(p, inode->i_version);

	} else {

		write32(p, stat->ctime.tv_sec);

		write32(p, stat->ctime.tv_nsec);

	}

}



static void write_cinfo(__be32 **p, struct nfsd4_change_info *c)

{

	write32(p, c->atomic);

	if (c->change_supported) {

		write64(p, c->before_change);

		write64(p, c->after_change);

	} else {

		write32(p, c->before_ctime_sec);

		write32(p, c->before_ctime_nsec);

		write32(p, c->after_ctime_sec);

		write32(p, c->after_ctime_nsec);

	}

}



#define RESERVE_SPACE(nbytes)	do {				\

	p = resp->p;						\
@@ -1849,16 +1877,9 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp, 
			WRITE32(NFS4_FH_PERSISTENT|NFS4_FH_VOL_RENAME);

	}

	if (bmval0 & FATTR4_WORD0_CHANGE) {

		/*

		 * Note: This _must_ be consistent with the scheme for writing

		 * change_info, so any changes made here must be reflected there

		 * as well.  (See xdr4.h:set_change_info() and the WRITECINFO()

		 * macro above.)

		 */

		if ((buflen -= 8) < 0)

			goto out_resource;

		WRITE32(stat.ctime.tv_sec);

		WRITE32(stat.ctime.tv_nsec);

		write_change(&p, &stat, dentry->d_inode);

	}

	if (bmval0 & FATTR4_WORD0_SIZE) {

		if ((buflen -= 8) < 0)
@@ -2364,7 +2385,7 @@ nfsd4_encode_create(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_ 


	if (!nfserr) {

		RESERVE_SPACE(32);

		WRITECINFO(create->cr_cinfo);

		write_cinfo(&p, &create->cr_cinfo);

		WRITE32(2);

		WRITE32(create->cr_bmval[0]);

		WRITE32(create->cr_bmval[1]);
@@ -2475,7 +2496,7 @@ nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_li 


	if (!nfserr) {

		RESERVE_SPACE(20);

		WRITECINFO(link->li_cinfo);

		write_cinfo(&p, &link->li_cinfo);

		ADJUST_ARGS();

	}

	return nfserr;
@@ -2493,7 +2514,7 @@ nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_op 


	nfsd4_encode_stateid(resp, &open->op_stateid);

	RESERVE_SPACE(40);

	WRITECINFO(open->op_cinfo);

	write_cinfo(&p, &open->op_cinfo);

	WRITE32(open->op_rflags);

	WRITE32(2);

	WRITE32(open->op_bmval[0]);
@@ -2771,7 +2792,7 @@ nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_ 


	if (!nfserr) {

		RESERVE_SPACE(20);

		WRITECINFO(remove->rm_cinfo);

		write_cinfo(&p, &remove->rm_cinfo);

		ADJUST_ARGS();

	}

	return nfserr;
@@ -2784,8 +2805,8 @@ nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_ 


	if (!nfserr) {

		RESERVE_SPACE(40);

		WRITECINFO(rename->rn_sinfo);

		WRITECINFO(rename->rn_tinfo);

		write_cinfo(&p, &rename->rn_sinfo);

		write_cinfo(&p, &rename->rn_tinfo);

		ADJUST_ARGS();

	}

	return nfserr;

include/linux/nfsd/nfsfh.h

+7 −0
Original line number Diff line number Diff line
@@ -151,9 +151,15 @@ typedef struct svc_fh { 
	__u64			fh_pre_size;	/* size before operation */

	struct timespec		fh_pre_mtime;	/* mtime before oper */

	struct timespec		fh_pre_ctime;	/* ctime before oper */

	/*

	 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)

	 *  to find out if it is valid.

	 */

	u64			fh_pre_change;



	/* Post-op attributes saved in fh_unlock */

	struct kstat		fh_post_attr;	/* full attrs after operation */

	u64			fh_post_change; /* nfsv4 change; see above */

#endif /* CONFIG_NFSD_V3 */



} svc_fh;
@@ -298,6 +304,7 @@ fill_pre_wcc(struct svc_fh *fhp) 
		fhp->fh_pre_mtime = inode->i_mtime;

		fhp->fh_pre_ctime = inode->i_ctime;

		fhp->fh_pre_size  = inode->i_size;

		fhp->fh_pre_change = inode->i_version;

		fhp->fh_pre_saved = 1;

	}

}

include/linux/nfsd/xdr4.h

+13 −4
Original line number Diff line number Diff line
@@ -64,10 +64,13 @@ static inline bool nfsd4_has_session(struct nfsd4_compound_state *cs) 


struct nfsd4_change_info {

	u32		atomic;

	bool		change_supported;

	u32		before_ctime_sec;

	u32		before_ctime_nsec;

	u64		before_change;

	u32		after_ctime_sec;

	u32		after_ctime_nsec;

	u64		after_change;

};



struct nfsd4_access {
@@ -503,11 +506,17 @@ set_change_info(struct nfsd4_change_info *cinfo, struct svc_fh *fhp) 
{

	BUG_ON(!fhp->fh_pre_saved || !fhp->fh_post_saved);

	cinfo->atomic = 1;

	cinfo->change_supported = IS_I_VERSION(fhp->fh_dentry->d_inode);

	if (cinfo->change_supported) {

		cinfo->before_change = fhp->fh_pre_change;

		cinfo->after_change = fhp->fh_post_change;

	} else {

		cinfo->before_ctime_sec = fhp->fh_pre_ctime.tv_sec;

		cinfo->before_ctime_nsec = fhp->fh_pre_ctime.tv_nsec;

		cinfo->after_ctime_sec = fhp->fh_post_attr.ctime.tv_sec;

		cinfo->after_ctime_nsec = fhp->fh_post_attr.ctime.tv_nsec;

	}

}



int nfs4svc_encode_voidres(struct svc_rqst *, __be32 *, void *);

int nfs4svc_decode_compoundargs(struct svc_rqst *, __be32 *,