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    Subject[PATCH 1/25] bug: nfsd/nfs4xdr.c misuse of ERR_PTR()

    a) ERR_PTR(nfserr_something) is a bad idea;
    IS_ERR() will be false for it.
    b) mixing nfserr_.... with -EOPNOTSUPP is
    even worse idea.

    nfsd4_path() does both; caller expects to get NFS protocol error
    out it if anything goes wrong, but if it does we either do not
    notice (see (a)) or get host-endian negative (see (b)).

    IOW, that's a case when we can't use ERR_PTR() to return
    error, even though we return a pointer in case of success.

    Signed-off-by: Al Viro <>
    fs/nfsd/nfs4xdr.c | 21 +++++++++++----------
    1 files changed, 11 insertions(+), 10 deletions(-)

    diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
    index 41fc241..77be0c4 100644
    --- a/fs/nfsd/nfs4xdr.c
    +++ b/fs/nfsd/nfs4xdr.c
    @@ -1292,16 +1292,15 @@ static int nfsd4_encode_fs_location4(str
    * Returned string is safe to use as long as the caller holds a reference
    * to @exp.
    -static char *nfsd4_path(struct svc_rqst *rqstp, struct svc_export *exp)
    +static char *nfsd4_path(struct svc_rqst *rqstp, struct svc_export *exp, u32 *stat)
    struct svc_fh tmp_fh;
    char *path, *rootpath;
    - int stat;

    fh_init(&tmp_fh, NFS4_FHSIZE);
    - stat = exp_pseudoroot(rqstp->rq_client, &tmp_fh, &rqstp->rq_chandle);
    - if (stat)
    - return ERR_PTR(stat);
    + *stat = exp_pseudoroot(rqstp->rq_client, &tmp_fh, &rqstp->rq_chandle);
    + if (*stat)
    + return NULL;
    rootpath = tmp_fh.fh_export->ex_path;

    path = exp->ex_path;
    @@ -1309,7 +1308,8 @@ static char *nfsd4_path(struct svc_rqst
    if (strncmp(path, rootpath, strlen(rootpath))) {
    printk("nfsd: fs_locations failed;"
    "%s is not contained in %s\n", path, rootpath);
    - return ERR_PTR(-EOPNOTSUPP);
    + *stat = nfserr_notsupp;
    + return NULL;

    return path + strlen(rootpath);
    @@ -1322,13 +1322,14 @@ static int nfsd4_encode_fs_locations(str
    struct svc_export *exp,
    u32 **pp, int *buflen)
    - int status, i;
    + u32 status;
    + int i;
    u32 *p = *pp;
    struct nfsd4_fs_locations *fslocs = &exp->ex_fslocs;
    - char *root = nfsd4_path(rqstp, exp);
    + char *root = nfsd4_path(rqstp, exp, &status);

    - if (IS_ERR(root))
    - return PTR_ERR(root);
    + if (status)
    + return status;
    status = nfsd4_encode_components('/', root, &p, buflen);
    if (status)
    return status;

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      Last update: 2006-10-10 05:13    [W:0.031 / U:110.052 seconds]
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