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knfsd: nfsd: make all exp_finding functions return -errno's on err

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Currently exp_find(), exp_get_by_name(), and friends, return an export on
success, and on failure return:

	errors -EAGAIN (drop this request pending an upcall) or
		-ETIMEDOUT (an upcall has timed out), or
	return NULL, which can mean either that there was a memory allocation
		failure, or that an export was not found, or that a passed-in
		export lacks an auth_domain.

Many callers seem to assume that NULL means that an export was not found,
which may lead to bugs in the case of a memory allocation failure.

Modify these functions to distinguish between the two NULL cases by returning
either -ENOENT or -ENOMEM.  They now never return NULL.  We get to simplify
some code in the process.

We return -ENOENT in the case of a missing auth_domain.  This case should
probably be removed (or converted to a bug) after confirming that it can never
happen.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
J. Bruce Fields 2007-07-17 04:04:40 -07:00 committed by Linus Torvalds
parent 47f9940c55
commit 2d3bb25209
3 changed files with 32 additions and 46 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

58
fs/nfsd/export.c
View file

@ -739,16 +739,18 @@ exp_find_key(svc_client *clp, int fsid_type, u32 *fsidv, struct cache_req *reqp)
int err;
if (!clp)
return NULL;
return ERR_PTR(-ENOENT);
key.ek_client = clp;
key.ek_fsidtype = fsid_type;
memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
ek = svc_expkey_lookup(&key);
if (ek != NULL)
if ((err = cache_check(&svc_expkey_cache, &ek->h, reqp)))
ek = ERR_PTR(err);
if (ek == NULL)
return ERR_PTR(-ENOMEM);
err = cache_check(&svc_expkey_cache, &ek->h, reqp);
if (err)
return ERR_PTR(err);
return ek;
}
@ -809,30 +811,21 @@ exp_get_by_name(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
struct cache_req *reqp)
{
struct svc_export *exp, key;
int err;
if (!clp)
return NULL;
return ERR_PTR(-ENOENT);
key.ex_client = clp;
key.ex_mnt = mnt;
key.ex_dentry = dentry;
exp = svc_export_lookup(&key);
if (exp != NULL) {
int err;
err = cache_check(&svc_export_cache, &exp->h, reqp);
switch (err) {
case 0: break;
case -EAGAIN:
case -ETIMEDOUT:
exp = ERR_PTR(err);
break;
default:
exp = NULL;
}
}
if (exp == NULL)
return ERR_PTR(-ENOMEM);
err = cache_check(&svc_export_cache, &exp->h, reqp);
if (err)
return ERR_PTR(err);
return exp;
}
@ -848,7 +841,7 @@ exp_parent(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
dget(dentry);
exp = exp_get_by_name(clp, mnt, dentry, reqp);
while (exp == NULL && !IS_ROOT(dentry)) {
while (PTR_ERR(exp) == -ENOENT && !IS_ROOT(dentry)) {
struct dentry *parent;
parent = dget_parent(dentry);
@ -901,7 +894,7 @@ static void exp_fsid_unhash(struct svc_export *exp)
return;
ek = exp_get_fsid_key(exp->ex_client, exp->ex_fsid);
if (ek && !IS_ERR(ek)) {
if (!IS_ERR(ek)) {
ek->h.expiry_time = get_seconds()-1;
cache_put(&ek->h, &svc_expkey_cache);
}
@ -939,7 +932,7 @@ static void exp_unhash(struct svc_export *exp)
struct inode *inode = exp->ex_dentry->d_inode;
ek = exp_get_key(exp->ex_client, inode->i_sb->s_dev, inode->i_ino);
if (ek && !IS_ERR(ek)) {
if (!IS_ERR(ek)) {
ek->h.expiry_time = get_seconds()-1;
cache_put(&ek->h, &svc_expkey_cache);
}
@ -990,13 +983,12 @@ exp_export(struct nfsctl_export *nxp)
/* must make sure there won't be an ex_fsid clash */
if ((nxp->ex_flags & NFSEXP_FSID) &&
(fsid_key = exp_get_fsid_key(clp, nxp->ex_dev)) &&
!IS_ERR(fsid_key) &&
(!IS_ERR(fsid_key = exp_get_fsid_key(clp, nxp->ex_dev))) &&
fsid_key->ek_mnt &&
(fsid_key->ek_mnt != nd.mnt || fsid_key->ek_dentry != nd.dentry) )
goto finish;
if (exp) {
if (!IS_ERR(exp)) {
/* just a flags/id/fsid update */
exp_fsid_unhash(exp);
@ -1105,7 +1097,7 @@ exp_unexport(struct nfsctl_export *nxp)
err = -EINVAL;
exp = exp_get_by_name(dom, nd.mnt, nd.dentry, NULL);
path_release(&nd);
if (!exp)
if (IS_ERR(exp))
goto out_domain;
exp_do_unexport(exp);
@ -1150,10 +1142,6 @@ exp_rootfh(svc_client *clp, char *path, struct knfsd_fh *f, int maxsize)
err = PTR_ERR(exp);
goto out;
}
if (!exp) {
dprintk("nfsd: exp_rootfh export not found.\n");
goto out;
}
/*
* fh must be initialized before calling fh_compose
@ -1177,13 +1165,13 @@ exp_find(struct auth_domain *clp, int fsid_type, u32 *fsidv,
{
struct svc_export *exp;
struct svc_expkey *ek = exp_find_key(clp, fsid_type, fsidv, reqp);
if (!ek || IS_ERR(ek))
if (IS_ERR(ek))
return ERR_PTR(PTR_ERR(ek));
exp = exp_get_by_name(clp, ek->ek_mnt, ek->ek_dentry, reqp);
cache_put(&ek->h, &svc_expkey_cache);
if (!exp || IS_ERR(exp))
if (IS_ERR(exp))
return ERR_PTR(PTR_ERR(exp));
return exp;
}
@ -1205,10 +1193,10 @@ exp_pseudoroot(struct auth_domain *clp, struct svc_fh *fhp,
mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
exp = exp_find(clp, FSID_NUM, fsidv, creq);
if (PTR_ERR(exp) == -ENOENT)
return nfserr_perm;
if (IS_ERR(exp))
return nfserrno(PTR_ERR(exp));
if (exp == NULL)
return nfserr_perm;
rv = fh_compose(fhp, exp, exp->ex_dentry, NULL);
exp_put(exp);
return rv;

11
fs/nfsd/nfsfh.c
View file

@ -160,16 +160,15 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
&rqstp->rq_chandle);
}
if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
|| PTR_ERR(exp) == -ETIMEDOUT)) {
error = nfserr_stale;
if (PTR_ERR(exp) == -ENOENT)
goto out;
if (IS_ERR(exp)) {
error = nfserrno(PTR_ERR(exp));
goto out;
}
error = nfserr_stale;
if (!exp || IS_ERR(exp))
goto out;
/* Check if the request originated from a secure port. */
error = nfserr_perm;
if (!rqstp->rq_secure && EX_SECURE(exp)) {

9
fs/nfsd/vfs.c
View file

@ -192,15 +192,14 @@ nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
exp2 = exp_parent(exp->ex_client, mnt, dentry,
&rqstp->rq_chandle);
if (IS_ERR(exp2)) {
if (PTR_ERR(exp2) == -ENOENT) {
dput(dentry);
dentry = dget(dparent);
} else if (IS_ERR(exp2)) {
host_err = PTR_ERR(exp2);
dput(dentry);
mntput(mnt);
goto out_nfserr;
}
if (!exp2) {
dput(dentry);
dentry = dget(dparent);
} else {
exp_put(exp);
exp = exp2;