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NFS: Replace the READ_PLUS decoding code
We now take a 2-step process that allows us to place data and hole segments directly at their final position in the xdr_stream without needing to do a bunch of redundant copies to expand holes. Due to the variable lengths of each segment, the xdr metadata might cross page boundaries which I account for by setting a small scratch buffer so xdr_inline_decode() won't fail. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Anna Schumaker
Trond Myklebust
parent
e1bd87608d
commit
d3b00a802c
@ -1025,73 +1025,84 @@ static int decode_deallocate(struct xdr_stream *xdr, struct nfs42_falloc_res *re
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return decode_op_hdr(xdr, OP_DEALLOCATE);
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}
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static int decode_read_plus_data(struct xdr_stream *xdr,
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struct nfs_pgio_args *args,
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struct nfs_pgio_res *res)
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{
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uint32_t count, recvd;
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struct read_plus_segment {
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enum data_content4 type;
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uint64_t offset;
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union {
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struct {
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uint64_t length;
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} hole;
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struct {
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uint32_t length;
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unsigned int from;
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} data;
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};
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};
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static inline uint64_t read_plus_segment_length(struct read_plus_segment *seg)
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{
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return seg->type == NFS4_CONTENT_DATA ? seg->data.length : seg->hole.length;
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}
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static int decode_read_plus_segment(struct xdr_stream *xdr,
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struct read_plus_segment *seg)
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{
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__be32 *p;
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p = xdr_inline_decode(xdr, 8 + 4);
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p = xdr_inline_decode(xdr, 4);
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if (!p)
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return 1;
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return -EIO;
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seg->type = be32_to_cpup(p++);
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p = xdr_decode_hyper(p, &offset);
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count = be32_to_cpup(p);
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recvd = xdr_align_data(xdr, res->count, xdr_align_size(count));
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if (recvd > count)
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recvd = count;
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if (res->count + recvd > args->count) {
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if (args->count > res->count)
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res->count += args->count - res->count;
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return 1;
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}
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res->count += recvd;
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if (count > recvd)
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return 1;
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p = xdr_inline_decode(xdr, seg->type == NFS4_CONTENT_DATA ? 12 : 16);
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if (!p)
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return -EIO;
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p = xdr_decode_hyper(p, &seg->offset);
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if (seg->type == NFS4_CONTENT_DATA) {
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struct xdr_buf buf;
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uint32_t len = be32_to_cpup(p);
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seg->data.length = len;
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seg->data.from = xdr_stream_pos(xdr);
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if (!xdr_stream_subsegment(xdr, &buf, xdr_align_size(len)))
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return -EIO;
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} else if (seg->type == NFS4_CONTENT_HOLE) {
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xdr_decode_hyper(p, &seg->hole.length);
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} else
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return -EINVAL;
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return 0;
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}
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static int decode_read_plus_hole(struct xdr_stream *xdr,
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struct nfs_pgio_args *args,
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struct nfs_pgio_res *res, uint32_t *eof)
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static int process_read_plus_segment(struct xdr_stream *xdr,
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struct nfs_pgio_args *args,
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struct nfs_pgio_res *res,
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struct read_plus_segment *seg)
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{
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uint64_t offset, length, recvd;
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__be32 *p;
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unsigned long offset = seg->offset;
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unsigned long length = read_plus_segment_length(seg);
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unsigned int bufpos;
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p = xdr_inline_decode(xdr, 8 + 8);
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if (!p)
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return 1;
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p = xdr_decode_hyper(p, &offset);
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p = xdr_decode_hyper(p, &length);
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if (offset != args->offset + res->count) {
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/* Server returned an out-of-sequence extent */
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if (offset > args->offset + res->count ||
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offset + length < args->offset + res->count) {
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dprintk("NFS: server returned out of sequence extent: "
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"offset/size = %llu/%llu != expected %llu\n",
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(unsigned long long)offset,
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(unsigned long long)length,
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(unsigned long long)(args->offset +
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res->count));
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return 1;
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}
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length -= args->offset + res->count - offset;
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if (offset + length < args->offset)
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return 0;
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else if (offset > args->offset + args->count) {
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res->eof = 0;
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return 0;
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} else if (offset < args->offset) {
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length -= (args->offset - offset);
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offset = args->offset;
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} else if (offset + length > args->offset + args->count) {
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length = (args->offset + args->count) - offset;
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res->eof = 0;
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}
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if (length + res->count > args->count) {
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*eof = 0;
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if (unlikely(res->count >= args->count))
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return 1;
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length = args->count - res->count;
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}
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recvd = xdr_expand_hole(xdr, res->count, length);
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res->count += recvd;
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if (recvd < length)
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return 1;
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return 0;
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bufpos = xdr->buf->head[0].iov_len + (offset - args->offset);
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if (seg->type == NFS4_CONTENT_HOLE)
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return xdr_stream_zero(xdr, bufpos, length);
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else
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return xdr_stream_move_subsegment(xdr, seg->data.from, bufpos, length);
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}
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static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
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@ -1099,8 +1110,10 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
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struct nfs_pgio_header *hdr =
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container_of(res, struct nfs_pgio_header, res);
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struct nfs_pgio_args *args = &hdr->args;
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uint32_t eof, segments, type;
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uint32_t segments;
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struct read_plus_segment *segs;
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int status, i;
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char scratch_buf[16];
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__be32 *p;
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status = decode_op_hdr(xdr, OP_READ_PLUS);
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@ -1112,38 +1125,31 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
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return -EIO;
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res->count = 0;
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eof = be32_to_cpup(p++);
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res->eof = be32_to_cpup(p++);
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segments = be32_to_cpup(p++);
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if (segments == 0)
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goto out;
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return status;
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segs = kmalloc_array(segments, sizeof(*segs), GFP_KERNEL);
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if (!segs)
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return -ENOMEM;
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xdr_set_scratch_buffer(xdr, &scratch_buf, 32);
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status = -EIO;
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for (i = 0; i < segments; i++) {
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p = xdr_inline_decode(xdr, 4);
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if (!p)
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goto early_out;
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type = be32_to_cpup(p++);
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if (type == NFS4_CONTENT_DATA)
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status = decode_read_plus_data(xdr, args, res);
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else if (type == NFS4_CONTENT_HOLE)
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status = decode_read_plus_hole(xdr, args, res, &eof);
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else
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return -EINVAL;
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status = decode_read_plus_segment(xdr, &segs[i]);
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if (status < 0)
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return status;
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if (status > 0)
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goto early_out;
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goto out;
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}
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xdr_set_pagelen(xdr, xdr_align_size(args->count));
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for (i = segments; i > 0; i--)
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res->count += process_read_plus_segment(xdr, args, res, &segs[i-1]);
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status = 0;
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out:
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res->eof = eof;
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return 0;
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early_out:
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if (unlikely(!i))
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return -EIO;
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res->eof = 0;
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return 0;
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kfree(segs);
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return status;
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}
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static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)
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