Messages in this thread Patch in this message | | | From | NeilBrown <> | Date | Mon, 3 Apr 2006 15:18:46 +1000 | Subject | [PATCH 008 of 16] knfsd: nfsd4: fix corruption of returned data when using 64k pages |
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In v4 we grab an extra page just for the padding of returned data. The formula that the rpc server uses to allocate pages for the response doesn't take into account this extra page.
Instead of adjusting those formulae, we adopt the same solution as v2 and v3, and put the "tail" data in the same page as the "head" data.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de>
### Diffstat output ./fs/nfsd/nfs4xdr.c | 42 +++++++++++++++++------------------------- 1 file changed, 17 insertions(+), 25 deletions(-)
diff ./fs/nfsd/nfs4xdr.c~current~ ./fs/nfsd/nfs4xdr.c --- ./fs/nfsd/nfs4xdr.c~current~ 2006-04-03 15:12:06.000000000 +1000 +++ ./fs/nfsd/nfs4xdr.c 2006-04-03 15:12:11.000000000 +1000 @@ -2084,27 +2084,20 @@ nfsd4_encode_read(struct nfsd4_compoundr WRITE32(eof); WRITE32(maxcount); ADJUST_ARGS(); - resp->xbuf->head[0].iov_len = ((char*)resp->p) - (char*)resp->xbuf->head[0].iov_base; - + resp->xbuf->head[0].iov_len = (char*)p + - (char*)resp->xbuf->head[0].iov_base; resp->xbuf->page_len = maxcount; - /* read zero bytes -> don't set up tail */ - if(!maxcount) - return 0; - - /* set up page for remaining responses */ - svc_take_page(resp->rqstp); - resp->xbuf->tail[0].iov_base = - page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]); - resp->rqstp->rq_restailpage = resp->rqstp->rq_resused-1; + /* Use rest of head for padding and remaining ops: */ + resp->rqstp->rq_restailpage = 0; + resp->xbuf->tail[0].iov_base = p; resp->xbuf->tail[0].iov_len = 0; - resp->p = resp->xbuf->tail[0].iov_base; - resp->end = resp->p + PAGE_SIZE/4; - if (maxcount&3) { - *(resp->p)++ = 0; + RESERVE_SPACE(4); + WRITE32(0); resp->xbuf->tail[0].iov_base += maxcount&3; resp->xbuf->tail[0].iov_len = 4 - (maxcount&3); + ADJUST_ARGS(); } return 0; } @@ -2141,21 +2134,20 @@ nfsd4_encode_readlink(struct nfsd4_compo WRITE32(maxcount); ADJUST_ARGS(); - resp->xbuf->head[0].iov_len = ((char*)resp->p) - (char*)resp->xbuf->head[0].iov_base; + resp->xbuf->head[0].iov_len = (char*)p + - (char*)resp->xbuf->head[0].iov_base; + resp->xbuf->page_len = maxcount; - svc_take_page(resp->rqstp); - resp->xbuf->tail[0].iov_base = - page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]); - resp->rqstp->rq_restailpage = resp->rqstp->rq_resused-1; + /* Use rest of head for padding and remaining ops: */ + resp->rqstp->rq_restailpage = 0; + resp->xbuf->tail[0].iov_base = p; resp->xbuf->tail[0].iov_len = 0; - resp->p = resp->xbuf->tail[0].iov_base; - resp->end = resp->p + PAGE_SIZE/4; - - resp->xbuf->page_len = maxcount; if (maxcount&3) { - *(resp->p)++ = 0; + RESERVE_SPACE(4); + WRITE32(0); resp->xbuf->tail[0].iov_base += maxcount&3; resp->xbuf->tail[0].iov_len = 4 - (maxcount&3); + ADJUST_ARGS(); } return 0; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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