diff mbox

[2/2] NFSv4: encode_attrs should not backfill the bitmap and attribute length

Message ID 1374098347-30196-2-git-send-email-Trond.Myklebust@netapp.com (mailing list archive)
State New, archived
Headers show

Commit Message

Trond Myklebust July 17, 2013, 9:59 p.m. UTC 
The attribute length is already calculated in advance. There is no
reason why we cannot calculate the bitmap in advance too so that
we don't have to play pointer games.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 fs/nfs/nfs4xdr.c | 121 ++++++++++++++++++++++++-------------------------------
 1 file changed, 53 insertions(+), 68 deletions(-)

Comments

Andre Heider July 18, 2013, 2:56 p.m. UTC | #1 
On Wed, Jul 17, 2013 at 11:59 PM, Trond Myklebust
<Trond.Myklebust@netapp.com> wrote:
> The attribute length is already calculated in advance. There is no
> reason why we cannot calculate the bitmap in advance too so that
> we don't have to play pointer games.
>
> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Tested-by: Andre Heider <a.heider@gmail.com>
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Andre Heider July 23, 2013, 3:59 p.m. UTC | #2 
Trond,

On Wed, Jul 17, 2013 at 11:59 PM, Trond Myklebust
<Trond.Myklebust@netapp.com> wrote:
> The attribute length is already calculated in advance. There is no
> reason why we cannot calculate the bitmap in advance too so that
> we don't have to play pointer games.

I'm sorry to report that this patch seems to be more than just a cleanup.

I just tested 3.11-rc2 against my FreeBSD server, and with just patch
1/2 (as in -rc2) I still get the failure upon `touch`. It fails with
or without Rick's server patch.

Applying this one on top of -rc2 fixes it.

Regards,
Andre
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diff mbox

Patch

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index c74d616..98f937b 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -997,12 +997,10 @@  static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 	int owner_namelen = 0;
 	int owner_grouplen = 0;
 	__be32 *p;
-	__be32 *q;
-	int len;
-	uint32_t bmval_len = 2;
-	uint32_t bmval0 = 0;
-	uint32_t bmval1 = 0;
-	uint32_t bmval2 = 0;
+	unsigned i;
+	uint32_t len = 0;
+	uint32_t bmval_len;
+	uint32_t bmval[3] = { 0 };
 
 	/*
 	 * We reserve enough space to write the entire attribute buffer at once.
@@ -1011,13 +1009,14 @@  static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 	 * = 40 bytes, plus any contribution from variable-length fields
 	 *            such as owner/group.
 	 */
-	len = 8;
-
-	/* Sigh */
-	if (iap->ia_valid & ATTR_SIZE)
+	if (iap->ia_valid & ATTR_SIZE) {
+		bmval[0] |= FATTR4_WORD0_SIZE;
 		len += 8;
-	if (iap->ia_valid & ATTR_MODE)
+	}
+	if (iap->ia_valid & ATTR_MODE) {
+		bmval[1] |= FATTR4_WORD1_MODE;
 		len += 4;
+	}
 	if (iap->ia_valid & ATTR_UID) {
 		owner_namelen = nfs_map_uid_to_name(server, iap->ia_uid, owner_name, IDMAP_NAMESZ);
 		if (owner_namelen < 0) {
@@ -1028,6 +1027,7 @@  static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 			owner_namelen = sizeof("nobody") - 1;
 			/* goto out; */
 		}
+		bmval[1] |= FATTR4_WORD1_OWNER;
 		len += 4 + (XDR_QUADLEN(owner_namelen) << 2);
 	}
 	if (iap->ia_valid & ATTR_GID) {
@@ -1039,92 +1039,77 @@  static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 			owner_grouplen = sizeof("nobody") - 1;
 			/* goto out; */
 		}
+		bmval[1] |= FATTR4_WORD1_OWNER_GROUP;
 		len += 4 + (XDR_QUADLEN(owner_grouplen) << 2);
 	}
-	if (iap->ia_valid & ATTR_ATIME_SET)
+	if (iap->ia_valid & ATTR_ATIME_SET) {
+		bmval[1] |= FATTR4_WORD1_TIME_ACCESS_SET;
 		len += 16;
-	else if (iap->ia_valid & ATTR_ATIME)
+	} else if (iap->ia_valid & ATTR_ATIME) {
+		bmval[1] |= FATTR4_WORD1_TIME_ACCESS_SET;
 		len += 4;
-	if (iap->ia_valid & ATTR_MTIME_SET)
+	}
+	if (iap->ia_valid & ATTR_MTIME_SET) {
+		bmval[1] |= FATTR4_WORD1_TIME_MODIFY_SET;
 		len += 16;
-	else if (iap->ia_valid & ATTR_MTIME)
+	} else if (iap->ia_valid & ATTR_MTIME) {
+		bmval[1] |= FATTR4_WORD1_TIME_MODIFY_SET;
 		len += 4;
+	}
 	if (label) {
 		len += 4 + 4 + 4 + (XDR_QUADLEN(label->len) << 2);
-		bmval_len = 3;
+		bmval[2] |= FATTR4_WORD2_SECURITY_LABEL;
 	}
 
-	len += bmval_len << 2;
-	p = reserve_space(xdr, len);
+	if (bmval[2] != 0)
+		bmval_len = 3;
+	else if (bmval[1] != 0)
+		bmval_len = 2;
+	else
+		bmval_len = 1;
+
+	p = reserve_space(xdr, 4 + (bmval_len << 2) + 4 + len);
 
 	/*
 	 * We write the bitmap length now, but leave the bitmap and the attribute
 	 * buffer length to be backfilled at the end of this routine.
 	 */
 	*p++ = cpu_to_be32(bmval_len);
-	q = p;
-	/* Skip bitmap entries + attrlen */
-	p += bmval_len + 1;
+	for (i = 0; i < bmval_len; i++)
+		*p++ = cpu_to_be32(bmval[i]);
+	*p++ = cpu_to_be32(len);
 
-	if (iap->ia_valid & ATTR_SIZE) {
-		bmval0 |= FATTR4_WORD0_SIZE;
+	if (bmval[0] & FATTR4_WORD0_SIZE)
 		p = xdr_encode_hyper(p, iap->ia_size);
-	}
-	if (iap->ia_valid & ATTR_MODE) {
-		bmval1 |= FATTR4_WORD1_MODE;
+	if (bmval[1] & FATTR4_WORD1_MODE)
 		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
-	}
-	if (iap->ia_valid & ATTR_UID) {
-		bmval1 |= FATTR4_WORD1_OWNER;
+	if (bmval[1] & FATTR4_WORD1_OWNER)
 		p = xdr_encode_opaque(p, owner_name, owner_namelen);
-	}
-	if (iap->ia_valid & ATTR_GID) {
-		bmval1 |= FATTR4_WORD1_OWNER_GROUP;
+	if (bmval[1] & FATTR4_WORD1_OWNER_GROUP)
 		p = xdr_encode_opaque(p, owner_group, owner_grouplen);
+	if (bmval[1] & FATTR4_WORD1_TIME_ACCESS_SET) {
+		if (iap->ia_valid & ATTR_ATIME_SET) {
+			*p++ = cpu_to_be32(NFS4_SET_TO_CLIENT_TIME);
+			p = xdr_encode_hyper(p, (s64)iap->ia_atime.tv_sec);
+			*p++ = cpu_to_be32(iap->ia_atime.tv_nsec);
+		} else
+			*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
 	}
-	if (iap->ia_valid & ATTR_ATIME_SET) {
-		bmval1 |= FATTR4_WORD1_TIME_ACCESS_SET;
-		*p++ = cpu_to_be32(NFS4_SET_TO_CLIENT_TIME);
-		p = xdr_encode_hyper(p, (s64)iap->ia_atime.tv_sec);
-		*p++ = cpu_to_be32(iap->ia_atime.tv_nsec);
-	}
-	else if (iap->ia_valid & ATTR_ATIME) {
-		bmval1 |= FATTR4_WORD1_TIME_ACCESS_SET;
-		*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
-	}
-	if (iap->ia_valid & ATTR_MTIME_SET) {
-		bmval1 |= FATTR4_WORD1_TIME_MODIFY_SET;
-		*p++ = cpu_to_be32(NFS4_SET_TO_CLIENT_TIME);
-		p = xdr_encode_hyper(p, (s64)iap->ia_mtime.tv_sec);
-		*p++ = cpu_to_be32(iap->ia_mtime.tv_nsec);
-	}
-	else if (iap->ia_valid & ATTR_MTIME) {
-		bmval1 |= FATTR4_WORD1_TIME_MODIFY_SET;
-		*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
+	if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
+		if (iap->ia_valid & ATTR_MTIME_SET) {
+			*p++ = cpu_to_be32(NFS4_SET_TO_CLIENT_TIME);
+			p = xdr_encode_hyper(p, (s64)iap->ia_mtime.tv_sec);
+			*p++ = cpu_to_be32(iap->ia_mtime.tv_nsec);
+		} else
+			*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
 	}
-	if (label) {
-		bmval2 |= FATTR4_WORD2_SECURITY_LABEL;
+	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
 		*p++ = cpu_to_be32(label->lfs);
 		*p++ = cpu_to_be32(label->pi);
 		*p++ = cpu_to_be32(label->len);
 		p = xdr_encode_opaque_fixed(p, label->label, label->len);
 	}
 
-	/*
-	 * Now we backfill the bitmap and the attribute buffer length.
-	 */
-	if (len != ((char *)p - (char *)q) + 4) {
-		printk(KERN_ERR "NFS: Attr length error, %u != %Zu\n",
-				len, ((char *)p - (char *)q) + 4);
-		BUG();
-	}
-	len = (char *)p - (char *)q - (bmval_len << 2);
-	*q++ = htonl(bmval0);
-	*q++ = htonl(bmval1);
-	if (bmval_len == 3)
-		*q++ = htonl(bmval2);
-	*q = htonl(len);
-
 /* out: */
 }