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author | J. Bruce Fields <bfields@redhat.com> | 2014-03-11 22:54:34 +0100 |
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committer | J. Bruce Fields <bfields@redhat.com> | 2014-05-30 23:31:53 +0200 |
commit | a8095f7e80fbf3e0efe4ee5cd3f509113c56290f (patch) | |
tree | d44c77ac05bd42e6e054bd8b4cf356d5703d14a8 | |
parent | nfsd4: remove redundant encode buffer size checking (diff) | |
download | linux-a8095f7e80fbf3e0efe4ee5cd3f509113c56290f.tar.xz linux-a8095f7e80fbf3e0efe4ee5cd3f509113c56290f.zip |
nfsd4: size-checking cleanup
Better variable name, some comments, etc.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
-rw-r--r-- | fs/nfsd/nfs4proc.c | 9 | ||||
-rw-r--r-- | fs/nfsd/nfs4xdr.c | 29 |
2 files changed, 21 insertions, 17 deletions
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index a5b666ca560d..3ce431b9b577 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -1279,7 +1279,6 @@ nfsd4_proc_compound(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate = &resp->cstate; struct svc_fh *current_fh = &cstate->current_fh; struct svc_fh *save_fh = &cstate->save_fh; - u32 plen = 0; __be32 status; svcxdr_init_encode(rqstp, resp); @@ -1349,9 +1348,13 @@ nfsd4_proc_compound(struct svc_rqst *rqstp, /* If op is non-idempotent */ if (opdesc->op_flags & OP_MODIFIES_SOMETHING) { - plen = opdesc->op_rsize_bop(rqstp, op); /* - * If there's still another operation, make sure + * Don't execute this op if we couldn't encode a + * succesful reply: + */ + u32 plen = opdesc->op_rsize_bop(rqstp, op); + /* + * Plus if there's another operation, make sure * we'll have space to at least encode an error: */ if (resp->opcnt < args->opcnt) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index df643e0fb6b3..bd529e523087 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -3739,35 +3739,36 @@ static nfsd4_enc nfsd4_enc_ops[] = { }; /* - * Calculate the total amount of memory that the compound response has taken - * after encoding the current operation with pad. + * Calculate whether we still have space to encode repsize bytes. + * There are two considerations: + * - For NFS versions >=4.1, the size of the reply must stay within + * session limits + * - For all NFS versions, we must stay within limited preallocated + * buffer space. * - * pad: if operation is non-idempotent, pad was calculate by op_rsize_bop() - * which was specified at nfsd4_operation, else pad is zero. - * - * Compare this length to the session se_fmaxresp_sz and se_fmaxresp_cached. - * - * Our se_fmaxresp_cached will always be a multiple of PAGE_SIZE, and so - * will be at least a page and will therefore hold the xdr_buf head. + * This is called before the operation is processed, so can only provide + * an upper estimate. For some nonidempotent operations (such as + * getattr), it's not necessarily a problem if that estimate is wrong, + * as we can fail it after processing without significant side effects. */ -__be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 pad) +__be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize) { struct xdr_buf *buf = &resp->rqstp->rq_res; struct nfsd4_session *session = resp->cstate.session; - struct nfsd4_slot *slot = resp->cstate.slot; int slack_bytes = (char *)resp->xdr.end - (char *)resp->xdr.p; if (nfsd4_has_session(&resp->cstate)) { + struct nfsd4_slot *slot = resp->cstate.slot; - if (buf->len + pad > session->se_fchannel.maxresp_sz) + if (buf->len + respsize > session->se_fchannel.maxresp_sz) return nfserr_rep_too_big; if ((slot->sl_flags & NFSD4_SLOT_CACHETHIS) && - buf->len + pad > session->se_fchannel.maxresp_cached) + buf->len + respsize > session->se_fchannel.maxresp_cached) return nfserr_rep_too_big_to_cache; } - if (pad > slack_bytes) { + if (respsize > slack_bytes) { WARN_ON_ONCE(nfsd4_has_session(&resp->cstate)); return nfserr_resource; } |