On Sat, Feb 21, 2009 at 08:04:38AM +1100, Neil Brown wrote:
> On Friday February 20, bfields@xxxxxxxxxxxx wrote:
> > On Sat, Feb 21, 2009 at 06:47:58AM +1100, Neil Brown wrote:
Once upon a time, I said:
> > > > By the way, I have one sadly neglected todo here: ext4 has a real nfsv4
> > > > changeattribute, which needs to be hooked up to the nfsd code.
> > >
> > > Does it?
> > > I just had a quick look, found that it stores a 64 bit number on disk
> > > which is stored in inode->i_version.
> > > And this is incremented for directory operations. But it doesn't seem
> > > to be changed for file operations.
> > >
> > > But maybe I missed something.
> >
> > After some mucking around with git and git grep... looks like the
> > inode_inc_iversion() calls do the job. Note there's an i_version mount
> > option that's required.
>
> Ahh.... Now if only they had called that function
> "inode_inc_i_version", then my grep would have found it...
>
> So in nfsd we can simply do:
>
> if (IS_I_VERSION(fhp->fh_dentry->d_inode)) {
> change_attribute = fhp->fh_dentry->d_inode->i_version;
> } else {
> change_attribute = kstat.ctime;
> }
>
> ??
There's also the pre-/post- op attributes to take care of. I'm thinking
of applying something like the following.
Actually, I did this and then realized: I'm using IS_I_VERSION(inode) to
turn on use of the i_version as the change attribute on both files and
directories. But it actually only makes a difference for files.
So I guess I should just be using i_version as the change attribute
unconditionally for directories? (Will that work on any filesystem?)
--b.
commit 6bc1eaa4eb1bb8af1878be354962e6cedcaece60
Author: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
Date: Thu Apr 16 17:33:25 2009 -0400
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: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
Cc: Theodore Tso <tytso@xxxxxxx>
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 17d0dd9..01d4ec1 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -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
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 4a71fcd..12d36a7 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -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;
diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h
index afa1901..8f641c9 100644
--- a/include/linux/nfsd/nfsfh.h
+++ b/include/linux/nfsd/nfsfh.h
@@ -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;
}
}
diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
index f80d601..d0f050f 100644
--- a/include/linux/nfsd/xdr4.h
+++ b/include/linux/nfsd/xdr4.h
@@ -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 {
@@ -503,10 +506,16 @@ 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->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;
+ 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 *);
--
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