From ed748aacb8e3318fa2cf24e1c197d35b5fd29605 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 12 Sep 2011 19:37:06 -0400 Subject: [PATCH] NFSD: Cleanup for nfsd4_path() 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 Reviewed-by: Jeff Layton Signed-off-by: J. Bruce Fields --- 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 d491421cd70..99229b0c153 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -1009,7 +1009,7 @@ 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]; @@ -1029,7 +1029,7 @@ 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 182570bed47..5252d668196 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -1696,36 +1696,89 @@ 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_jukebox; - 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; } /* @@ -1739,11 +1792,8 @@ 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 8a31a20efe7..7ba3fd43f31 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 *); -- 2.41.0