On Fri, Sep 02, 2011 at 12:38:23PM -0400, Chuck Lever wrote:
> From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
>
> The current code is sort of hackish in that it assumes a referral is always
> matched to an export. When we add support for junctions that may not be the
> case.
> We can replace nfsd4_path() with a function that encodes the components
> directly from the dentries. Since nfsd4_path is currently the only user of
> the 'ex_pathname' field in struct svc_export, this has the added benefit
> of allowing us to get rid of that.
>
> Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> ---
>
> fs/nfsd/export.c | 4 +-
> fs/nfsd/nfs4xdr.c | 106 ++++++++++++++++++++++++++++++++-----------
> include/linux/nfsd/export.h | 1
> 3 files changed, 81 insertions(+), 30 deletions(-)
>
> diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
> index f4cc1e2..d9a6611 100644
> --- a/fs/nfsd/export.c
> +++ b/fs/nfsd/export.c
> @@ -1010,7 +1010,7 @@ rqst_exp_parent(struct svc_rqst *rqstp, struct path *path)
> return exp;
> }
>
> -static struct svc_export *find_fsidzero_export(struct svc_rqst *rqstp)
> +struct svc_export *rqst_find_fsidzero_export(struct svc_rqst *rqstp)
> {
> u32 fsidv[2];
>
> @@ -1030,7 +1030,7 @@ exp_pseudoroot(struct svc_rqst *rqstp, struct svc_fh *fhp)
> struct svc_export *exp;
> __be32 rv;
>
> - exp = find_fsidzero_export(rqstp);
> + exp = rqst_find_fsidzero_export(rqstp);
> if (IS_ERR(exp))
> return nfserrno(PTR_ERR(exp));
> rv = fh_compose(fhp, exp, exp->ex_path.dentry, NULL);
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index c8bf405..f7b068e 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -1697,36 +1697,89 @@ static __be32 nfsd4_encode_fs_location4(struct nfsd4_fs_location *location,
> }
>
> /*
> - * Return the path to an export point in the pseudo filesystem namespace
> - * Returned string is safe to use as long as the caller holds a reference
> - * to @exp.
> + * Encode a path in RFC3530 'pathname4' format
> */
> -static char *nfsd4_path(struct svc_rqst *rqstp, struct svc_export *exp, __be32 *stat)
> +static __be32 nfsd4_encode_path(const struct path *root,
> + const struct path *path, __be32 **pp, int *buflen)
> {
> - struct svc_fh tmp_fh;
> - char *path = NULL, *rootpath;
> - size_t rootlen;
> + struct path cur = {
> + .mnt = path->mnt,
> + .dentry = path->dentry,
> + };
> + __be32 *p = *pp;
> + struct dentry **components = NULL;
> + unsigned int ncomponents = 0;
> + __be32 err = nfserr_resource;
I've been fixing nfsd to return nfserr_jukebox for allocation errors,
and reserving nfserr_resource (not even available in 4.1) for cases
where the error is permanent (e.g. I just can't process a compound with
1000 ops).
Patch looks fine otherwise.
--b.
>
> - fh_init(&tmp_fh, NFS4_FHSIZE);
> - *stat = exp_pseudoroot(rqstp, &tmp_fh);
> - if (*stat)
> - return NULL;
> - rootpath = tmp_fh.fh_export->ex_pathname;
> + dprintk("nfsd4_encode_components(");
>
> - path = exp->ex_pathname;
> + path_get(&cur);
> + /* First walk the path up to the nfsd root, and store the
> + * dentries/path components in an array.
> + */
> + for (;;) {
> + if (cur.dentry == root->dentry && cur.mnt == root->mnt)
> + break;
> + if (cur.dentry == cur.mnt->mnt_root) {
> + if (follow_up(&cur))
> + continue;
> + goto out_free;
> + }
> + if ((ncomponents & 15) == 0) {
> + struct dentry **new;
> + new = krealloc(components,
> + sizeof(*new) * (ncomponents + 16),
> + GFP_KERNEL);
> + if (!new)
> + goto out_free;
> + components = new;
> + }
> + components[ncomponents++] = cur.dentry;
> + cur.dentry = dget_parent(cur.dentry);
> + }
>
> - rootlen = strlen(rootpath);
> - if (strncmp(path, rootpath, rootlen)) {
> - dprintk("nfsd: fs_locations failed;"
> - "%s is not contained in %s\n", path, rootpath);
> - *stat = nfserr_notsupp;
> - path = NULL;
> - goto out;
> + *buflen -= 4;
> + if (*buflen < 0)
> + goto out_free;
> + WRITE32(ncomponents);
> +
> + while (ncomponents) {
> + struct dentry *dentry = components[ncomponents - 1];
> + unsigned int len = dentry->d_name.len;
> +
> + *buflen -= 4 + (XDR_QUADLEN(len) << 2);
> + if (*buflen < 0)
> + goto out_free;
> + WRITE32(len);
> + WRITEMEM(dentry->d_name.name, len);
> + dprintk("/%s", dentry->d_name.name);
> + dput(dentry);
> + ncomponents--;
> }
> - path += rootlen;
> -out:
> - fh_put(&tmp_fh);
> - return path;
> +
> + *pp = p;
> + err = 0;
> +out_free:
> + dprintk(")\n");
> + while (ncomponents)
> + dput(components[--ncomponents]);
> + kfree(components);
> + path_put(&cur);
> + return err;
> +}
> +
> +static __be32 nfsd4_encode_fsloc_fsroot(struct svc_rqst *rqstp,
> + const struct path *path, __be32 **pp, int *buflen)
> +{
> + struct svc_export *exp_ps;
> + __be32 res;
> +
> + exp_ps = rqst_find_fsidzero_export(rqstp);
> + if (IS_ERR(exp_ps))
> + return nfserrno(PTR_ERR(exp_ps));
> + res = nfsd4_encode_path(&exp_ps->ex_path, path, pp, buflen);
> + exp_put(exp_ps);
> + return res;
> }
>
> /*
> @@ -1740,11 +1793,8 @@ static __be32 nfsd4_encode_fs_locations(struct svc_rqst *rqstp,
> int i;
> __be32 *p = *pp;
> struct nfsd4_fs_locations *fslocs = &exp->ex_fslocs;
> - char *root = nfsd4_path(rqstp, exp, &status);
>
> - if (status)
> - return status;
> - status = nfsd4_encode_components('/', root, &p, buflen);
> + status = nfsd4_encode_fsloc_fsroot(rqstp, &exp->ex_path, &p, buflen);
> if (status)
> return status;
> if ((*buflen -= 4) < 0)
> diff --git a/include/linux/nfsd/export.h b/include/linux/nfsd/export.h
> index 8a31a20..7ba3fd4 100644
> --- a/include/linux/nfsd/export.h
> +++ b/include/linux/nfsd/export.h
> @@ -137,6 +137,7 @@ struct svc_export * rqst_exp_get_by_name(struct svc_rqst *,
> struct path *);
> struct svc_export * rqst_exp_parent(struct svc_rqst *,
> struct path *);
> +struct svc_export * rqst_find_fsidzero_export(struct svc_rqst *);
> int exp_rootfh(struct auth_domain *,
> char *path, struct knfsd_fh *, int maxsize);
> __be32 exp_pseudoroot(struct svc_rqst *, struct svc_fh *);
>
> --
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