From bd7ea31b9e8a342be76e0fe8d638343886c2d8c5 Mon Sep 17 00:00:00 2001 From: Tom Tucker Date: Wed, 9 Feb 2011 19:45:28 +0000 Subject: RPCRDMA: Fix to XDR page base interpretation in marshalling logic. The RPCRDMA marshalling logic assumed that xdr->page_base was an offset into the first page of xdr->page_list. It is in fact an offset into the xdr->page_list itself, that is, it selects the first page in the page_list and the offset into that page. The symptom depended in part on the rpc_memreg_strategy, if it was FRMR, or some other one-shot mapping mode, the connection would get torn down on a base and bounds error. When the badly marshalled RPC was retransmitted it would reconnect, get the error, and tear down the connection again in a loop forever. This resulted in a hung-mount. For the other modes, it would result in silent data corruption. This bug is most easily reproduced by writing more data than the filesystem has space for. This fix corrects the page_base assumption and otherwise simplifies the iov mapping logic. Signed-off-by: Tom Tucker Signed-off-by: Trond Myklebust --- net/sunrpc/xprtrdma/rpc_rdma.c | 86 +++++++++++++++++++++--------------------- 1 file changed, 42 insertions(+), 44 deletions(-) (limited to 'net/sunrpc') diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index 2ac3f6e..554d081 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -87,6 +87,8 @@ rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos, enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg, int nsegs) { int len, n = 0, p; + int page_base; + struct page **ppages; if (pos == 0 && xdrbuf->head[0].iov_len) { seg[n].mr_page = NULL; @@ -95,34 +97,32 @@ rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos, ++n; } - if (xdrbuf->page_len && (xdrbuf->pages[0] != NULL)) { - if (n == nsegs) - return 0; - seg[n].mr_page = xdrbuf->pages[0]; - seg[n].mr_offset = (void *)(unsigned long) xdrbuf->page_base; - seg[n].mr_len = min_t(u32, - PAGE_SIZE - xdrbuf->page_base, xdrbuf->page_len); - len = xdrbuf->page_len - seg[n].mr_len; + len = xdrbuf->page_len; + ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT); + page_base = xdrbuf->page_base & ~PAGE_MASK; + p = 0; + while (len && n < nsegs) { + seg[n].mr_page = ppages[p]; + seg[n].mr_offset = (void *)(unsigned long) page_base; + seg[n].mr_len = min_t(u32, PAGE_SIZE - page_base, len); + BUG_ON(seg[n].mr_len > PAGE_SIZE); + len -= seg[n].mr_len; ++n; - p = 1; - while (len > 0) { - if (n == nsegs) - return 0; - seg[n].mr_page = xdrbuf->pages[p]; - seg[n].mr_offset = NULL; - seg[n].mr_len = min_t(u32, PAGE_SIZE, len); - len -= seg[n].mr_len; - ++n; - ++p; - } + ++p; + page_base = 0; /* page offset only applies to first page */ } + /* Message overflows the seg array */ + if (len && n == nsegs) + return 0; + if (xdrbuf->tail[0].iov_len) { /* the rpcrdma protocol allows us to omit any trailing * xdr pad bytes, saving the server an RDMA operation. */ if (xdrbuf->tail[0].iov_len < 4 && xprt_rdma_pad_optimize) return n; if (n == nsegs) + /* Tail remains, but we're out of segments */ return 0; seg[n].mr_page = NULL; seg[n].mr_offset = xdrbuf->tail[0].iov_base; @@ -296,6 +296,8 @@ rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad) int copy_len; unsigned char *srcp, *destp; struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt); + int page_base; + struct page **ppages; destp = rqst->rq_svec[0].iov_base; curlen = rqst->rq_svec[0].iov_len; @@ -324,28 +326,25 @@ rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad) __func__, destp + copy_len, curlen); rqst->rq_svec[0].iov_len += curlen; } - r_xprt->rx_stats.pullup_copy_count += copy_len; - npages = PAGE_ALIGN(rqst->rq_snd_buf.page_base+copy_len) >> PAGE_SHIFT; + + page_base = rqst->rq_snd_buf.page_base; + ppages = rqst->rq_snd_buf.pages + (page_base >> PAGE_SHIFT); + page_base &= ~PAGE_MASK; + npages = PAGE_ALIGN(page_base+copy_len) >> PAGE_SHIFT; for (i = 0; copy_len && i < npages; i++) { - if (i == 0) - curlen = PAGE_SIZE - rqst->rq_snd_buf.page_base; - else - curlen = PAGE_SIZE; + curlen = PAGE_SIZE - page_base; if (curlen > copy_len) curlen = copy_len; dprintk("RPC: %s: page %d destp 0x%p len %d curlen %d\n", __func__, i, destp, copy_len, curlen); - srcp = kmap_atomic(rqst->rq_snd_buf.pages[i], - KM_SKB_SUNRPC_DATA); - if (i == 0) - memcpy(destp, srcp+rqst->rq_snd_buf.page_base, curlen); - else - memcpy(destp, srcp, curlen); + srcp = kmap_atomic(ppages[i], KM_SKB_SUNRPC_DATA); + memcpy(destp, srcp+page_base, curlen); kunmap_atomic(srcp, KM_SKB_SUNRPC_DATA); rqst->rq_svec[0].iov_len += curlen; destp += curlen; copy_len -= curlen; + page_base = 0; } /* header now contains entire send message */ return pad; @@ -606,6 +605,8 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) { int i, npages, curlen, olen; char *destp; + struct page **ppages; + int page_base; curlen = rqst->rq_rcv_buf.head[0].iov_len; if (curlen > copy_len) { /* write chunk header fixup */ @@ -624,32 +625,29 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) olen = copy_len; i = 0; rpcx_to_rdmax(rqst->rq_xprt)->rx_stats.fixup_copy_count += olen; + page_base = rqst->rq_rcv_buf.page_base; + ppages = rqst->rq_rcv_buf.pages + (page_base >> PAGE_SHIFT); + page_base &= ~PAGE_MASK; + if (copy_len && rqst->rq_rcv_buf.page_len) { - npages = PAGE_ALIGN(rqst->rq_rcv_buf.page_base + + npages = PAGE_ALIGN(page_base + rqst->rq_rcv_buf.page_len) >> PAGE_SHIFT; for (; i < npages; i++) { - if (i == 0) - curlen = PAGE_SIZE - rqst->rq_rcv_buf.page_base; - else - curlen = PAGE_SIZE; + curlen = PAGE_SIZE - page_base; if (curlen > copy_len) curlen = copy_len; dprintk("RPC: %s: page %d" " srcp 0x%p len %d curlen %d\n", __func__, i, srcp, copy_len, curlen); - destp = kmap_atomic(rqst->rq_rcv_buf.pages[i], - KM_SKB_SUNRPC_DATA); - if (i == 0) - memcpy(destp + rqst->rq_rcv_buf.page_base, - srcp, curlen); - else - memcpy(destp, srcp, curlen); - flush_dcache_page(rqst->rq_rcv_buf.pages[i]); + destp = kmap_atomic(ppages[i], KM_SKB_SUNRPC_DATA); + memcpy(destp + page_base, srcp, curlen); + flush_dcache_page(ppages[i]); kunmap_atomic(destp, KM_SKB_SUNRPC_DATA); srcp += curlen; copy_len -= curlen; if (copy_len == 0) break; + page_base = 0; } rqst->rq_rcv_buf.page_len = olen - copy_len; } else -- cgit v1.1