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NFSv4: Fix exclusive create attributes encoding
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When using NFS4_CREATE_EXCLUSIVE4_1 mode, the client will overestimate the
amount of space that it needs for the attributes because it does so
before checking whether or not the server supports a given attribute.

Fix by checking the attribute mask earlier.

Signed-off-by: Trond Myklebust <[email protected]>
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@trondmypd
trondmypd committed May 8, 2017
1 parent 2e84611 commit 28cf22d
Showing 1 changed file with 35 additions and 40 deletions.
75 changes: 35 additions & 40 deletions fs/nfs/nfs4xdr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1000,8 +1000,9 @@ static void encode_nfs4_verifier(struct xdr_stream *xdr, const nfs4_verifier *ve

static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
const struct nfs4_label *label,
const umode_t *umask,
const struct nfs_server *server,
bool excl_check, const umode_t *umask)
const uint32_t attrmask[])
{
char owner_name[IDMAP_NAMESZ];
char owner_group[IDMAP_NAMESZ];
Expand All @@ -1016,22 +1017,20 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
/*
* We reserve enough space to write the entire attribute buffer at once.
*/
if (iap->ia_valid & ATTR_SIZE) {
if ((iap->ia_valid & ATTR_SIZE) && (attrmask[0] & FATTR4_WORD0_SIZE)) {
bmval[0] |= FATTR4_WORD0_SIZE;
len += 8;
}
if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
umask = NULL;
if (iap->ia_valid & ATTR_MODE) {
if (umask) {
if (umask && (attrmask[2] & FATTR4_WORD2_MODE_UMASK)) {
bmval[2] |= FATTR4_WORD2_MODE_UMASK;
len += 8;
} else {
} else if (attrmask[1] & FATTR4_WORD1_MODE) {
bmval[1] |= FATTR4_WORD1_MODE;
len += 4;
}
}
if (iap->ia_valid & ATTR_UID) {
if ((iap->ia_valid & ATTR_UID) && (attrmask[1] & FATTR4_WORD1_OWNER)) {
owner_namelen = nfs_map_uid_to_name(server, iap->ia_uid, owner_name, IDMAP_NAMESZ);
if (owner_namelen < 0) {
dprintk("nfs: couldn't resolve uid %d to string\n",
Expand All @@ -1044,7 +1043,8 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
bmval[1] |= FATTR4_WORD1_OWNER;
len += 4 + (XDR_QUADLEN(owner_namelen) << 2);
}
if (iap->ia_valid & ATTR_GID) {
if ((iap->ia_valid & ATTR_GID) &&
(attrmask[1] & FATTR4_WORD1_OWNER_GROUP)) {
owner_grouplen = nfs_map_gid_to_group(server, iap->ia_gid, owner_group, IDMAP_NAMESZ);
if (owner_grouplen < 0) {
dprintk("nfs: couldn't resolve gid %d to string\n",
Expand All @@ -1056,32 +1056,26 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
bmval[1] |= FATTR4_WORD1_OWNER_GROUP;
len += 4 + (XDR_QUADLEN(owner_grouplen) << 2);
}
if (iap->ia_valid & ATTR_ATIME_SET) {
bmval[1] |= FATTR4_WORD1_TIME_ACCESS_SET;
len += 16;
} else if (iap->ia_valid & ATTR_ATIME) {
bmval[1] |= FATTR4_WORD1_TIME_ACCESS_SET;
len += 4;
}
if (iap->ia_valid & ATTR_MTIME_SET) {
bmval[1] |= FATTR4_WORD1_TIME_MODIFY_SET;
len += 16;
} else if (iap->ia_valid & ATTR_MTIME) {
bmval[1] |= FATTR4_WORD1_TIME_MODIFY_SET;
len += 4;
if (attrmask[1] & FATTR4_WORD1_TIME_ACCESS_SET) {
if (iap->ia_valid & ATTR_ATIME_SET) {
bmval[1] |= FATTR4_WORD1_TIME_ACCESS_SET;
len += 16;
} else if (iap->ia_valid & ATTR_ATIME) {
bmval[1] |= FATTR4_WORD1_TIME_ACCESS_SET;
len += 4;
}
}

if (excl_check) {
const u32 *excl_bmval = server->exclcreat_bitmask;
bmval[0] &= excl_bmval[0];
bmval[1] &= excl_bmval[1];
bmval[2] &= excl_bmval[2];

if (!(excl_bmval[2] & FATTR4_WORD2_SECURITY_LABEL))
label = NULL;
if (attrmask[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
if (iap->ia_valid & ATTR_MTIME_SET) {
bmval[1] |= FATTR4_WORD1_TIME_MODIFY_SET;
len += 16;
} else if (iap->ia_valid & ATTR_MTIME) {
bmval[1] |= FATTR4_WORD1_TIME_MODIFY_SET;
len += 4;
}
}

if (label) {
if (label && (attrmask[2] & FATTR4_WORD2_SECURITY_LABEL)) {
len += 4 + 4 + 4 + (XDR_QUADLEN(label->len) << 2);
bmval[2] |= FATTR4_WORD2_SECURITY_LABEL;
}
Expand Down Expand Up @@ -1188,8 +1182,8 @@ static void encode_create(struct xdr_stream *xdr, const struct nfs4_create_arg *
}

encode_string(xdr, create->name->len, create->name->name);
encode_attrs(xdr, create->attrs, create->label, create->server, false,
&create->umask);
encode_attrs(xdr, create->attrs, create->label, &create->umask,
create->server, create->server->attr_bitmask);
}

static void encode_getattr_one(struct xdr_stream *xdr, uint32_t bitmap, struct compound_hdr *hdr)
Expand Down Expand Up @@ -1409,13 +1403,13 @@ static inline void encode_createmode(struct xdr_stream *xdr, const struct nfs_op
switch(arg->createmode) {
case NFS4_CREATE_UNCHECKED:
*p = cpu_to_be32(NFS4_CREATE_UNCHECKED);
encode_attrs(xdr, arg->u.attrs, arg->label, arg->server, false,
&arg->umask);
encode_attrs(xdr, arg->u.attrs, arg->label, &arg->umask,
arg->server, arg->server->attr_bitmask);
break;
case NFS4_CREATE_GUARDED:
*p = cpu_to_be32(NFS4_CREATE_GUARDED);
encode_attrs(xdr, arg->u.attrs, arg->label, arg->server, false,
&arg->umask);
encode_attrs(xdr, arg->u.attrs, arg->label, &arg->umask,
arg->server, arg->server->attr_bitmask);
break;
case NFS4_CREATE_EXCLUSIVE:
*p = cpu_to_be32(NFS4_CREATE_EXCLUSIVE);
Expand All @@ -1424,8 +1418,8 @@ static inline void encode_createmode(struct xdr_stream *xdr, const struct nfs_op
case NFS4_CREATE_EXCLUSIVE4_1:
*p = cpu_to_be32(NFS4_CREATE_EXCLUSIVE4_1);
encode_nfs4_verifier(xdr, &arg->u.verifier);
encode_attrs(xdr, arg->u.attrs, arg->label, arg->server, true,
&arg->umask);
encode_attrs(xdr, arg->u.attrs, arg->label, &arg->umask,
arg->server, arg->server->exclcreat_bitmask);
}
}

Expand Down Expand Up @@ -1681,7 +1675,8 @@ static void encode_setattr(struct xdr_stream *xdr, const struct nfs_setattrargs
{
encode_op_hdr(xdr, OP_SETATTR, decode_setattr_maxsz, hdr);
encode_nfs4_stateid(xdr, &arg->stateid);
encode_attrs(xdr, arg->iap, arg->label, server, false, NULL);
encode_attrs(xdr, arg->iap, arg->label, NULL, server,
server->attr_bitmask);
}

static void encode_setclientid(struct xdr_stream *xdr, const struct nfs4_setclientid *setclientid, struct compound_hdr *hdr)
Expand Down

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