From f5dcccd647da513a89f3b6ca392b0c1eb050b9fc Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Sat, 14 Nov 2020 13:45:35 -0500 Subject: [PATCH] NFSD: Update the NFSv2 READDIR entry encoder to use struct xdr_stream Signed-off-by: Chuck Lever --- fs/nfsd/nfsproc.c | 26 +++++++++++---- fs/nfsd/nfsxdr.c | 81 ++++++++++++++++++++++++++++++++++++++++++++--- fs/nfsd/xdr.h | 7 ++++ 3 files changed, 103 insertions(+), 11 deletions(-) diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index 1acff9f4aaf1..86d438fbd576 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -559,14 +559,27 @@ static void nfsd_init_dirlist_pages(struct svc_rqst *rqstp, struct nfsd_readdirres *resp, int count) { + struct xdr_buf *buf = &resp->dirlist; + struct xdr_stream *xdr = &resp->xdr; + count = min_t(u32, count, PAGE_SIZE); - /* Convert byte count to number of words (i.e. >> 2), - * and reserve room for the NULL ptr & eof flag (-2 words) */ - resp->buflen = (count >> 2) - 2; + memset(buf, 0, sizeof(*buf)); - resp->buffer = page_address(*rqstp->rq_next_page); + /* Reserve room for the NULL ptr & eof flag (-2 words) */ + buf->buflen = count - sizeof(__be32) * 2; + buf->pages = rqstp->rq_next_page; rqstp->rq_next_page++; + + /* This is xdr_init_encode(), but it assumes that + * the head kvec has already been consumed. */ + xdr_set_scratch_buffer(xdr, NULL, 0); + xdr->buf = buf; + xdr->page_ptr = buf->pages; + xdr->iov = NULL; + xdr->p = page_address(*buf->pages); + xdr->end = xdr->p + (PAGE_SIZE >> 2); + xdr->rqst = NULL; } /* @@ -585,12 +598,11 @@ nfsd_proc_readdir(struct svc_rqst *rqstp) nfsd_init_dirlist_pages(rqstp, resp, argp->count); - resp->offset = NULL; resp->common.err = nfs_ok; - /* Read directory and encode entries on the fly */ + resp->cookie_offset = 0; offset = argp->cookie; resp->status = nfsd_readdir(rqstp, &argp->fh, &offset, - &resp->common, nfssvc_encode_entry); + &resp->common, nfs2svc_encode_entry); nfssvc_encode_nfscookie(resp, offset); fh_put(&argp->fh); diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c index 9522e5c5f49d..1102d40ded03 100644 --- a/fs/nfsd/nfsxdr.c +++ b/fs/nfsd/nfsxdr.c @@ -576,12 +576,13 @@ nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p) { struct xdr_stream *xdr = &rqstp->rq_res_stream; struct nfsd_readdirres *resp = rqstp->rq_resp; + struct xdr_buf *dirlist = &resp->dirlist; if (!svcxdr_encode_stat(xdr, resp->status)) return 0; switch (resp->status) { case nfs_ok: - xdr_write_pages(xdr, &resp->page, 0, resp->count << 2); + xdr_write_pages(xdr, dirlist->pages, 0, dirlist->len); /* no more entries */ if (xdr_stream_encode_item_absent(xdr) < 0) return 0; @@ -623,14 +624,86 @@ nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p) * @resp: readdir result context * @offset: offset cookie to encode * + * The buffer space for the offset cookie has already been reserved + * by svcxdr_encode_entry_common(). */ void nfssvc_encode_nfscookie(struct nfsd_readdirres *resp, u32 offset) { - if (!resp->offset) + __be32 cookie = cpu_to_be32(offset); + + if (!resp->cookie_offset) return; - *resp->offset = cpu_to_be32(offset); - resp->offset = NULL; + write_bytes_to_xdr_buf(&resp->dirlist, resp->cookie_offset, &cookie, + sizeof(cookie)); + resp->cookie_offset = 0; +} + +static bool +svcxdr_encode_entry_common(struct nfsd_readdirres *resp, const char *name, + int namlen, loff_t offset, u64 ino) +{ + struct xdr_buf *dirlist = &resp->dirlist; + struct xdr_stream *xdr = &resp->xdr; + + if (xdr_stream_encode_item_present(xdr) < 0) + return false; + /* fileid */ + if (xdr_stream_encode_u32(xdr, (u32)ino) < 0) + return false; + /* name */ + if (xdr_stream_encode_opaque(xdr, name, min(namlen, NFS2_MAXNAMLEN)) < 0) + return false; + /* cookie */ + resp->cookie_offset = dirlist->len; + if (xdr_stream_encode_u32(xdr, ~0U) < 0) + return false; + + return true; +} + +/** + * nfs2svc_encode_entry - encode one NFSv2 READDIR entry + * @data: directory context + * @name: name of the object to be encoded + * @namlen: length of that name, in bytes + * @offset: the offset of the previous entry + * @ino: the fileid of this entry + * @d_type: unused + * + * Return values: + * %0: Entry was successfully encoded. + * %-EINVAL: An encoding problem occured, secondary status code in resp->common.err + * + * On exit, the following fields are updated: + * - resp->xdr + * - resp->common.err + * - resp->cookie_offset + */ +int nfs2svc_encode_entry(void *data, const char *name, int namlen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct readdir_cd *ccd = data; + struct nfsd_readdirres *resp = container_of(ccd, + struct nfsd_readdirres, + common); + unsigned int starting_length = resp->dirlist.len; + + /* The offset cookie for the previous entry */ + nfssvc_encode_nfscookie(resp, offset); + + if (!svcxdr_encode_entry_common(resp, name, namlen, offset, ino)) + goto out_toosmall; + + xdr_commit_encode(&resp->xdr); + resp->common.err = nfs_ok; + return 0; + +out_toosmall: + resp->cookie_offset = 0; + resp->common.err = nfserr_toosmall; + resp->dirlist.len = starting_length; + return -EINVAL; } int diff --git a/fs/nfsd/xdr.h b/fs/nfsd/xdr.h index 69a6efc71ecb..082f262a1bf9 100644 --- a/fs/nfsd/xdr.h +++ b/fs/nfsd/xdr.h @@ -106,15 +106,20 @@ struct nfsd_readres { }; struct nfsd_readdirres { + /* Components of the reply */ __be32 status; int count; + /* Used to encode the reply's entry list */ + struct xdr_stream xdr; + struct xdr_buf dirlist; struct readdir_cd common; __be32 * buffer; int buflen; __be32 * offset; struct page *page; + unsigned int cookie_offset; }; struct nfsd_statfsres { @@ -159,6 +164,8 @@ int nfssvc_encode_statfsres(struct svc_rqst *, __be32 *); int nfssvc_encode_readdirres(struct svc_rqst *, __be32 *); void nfssvc_encode_nfscookie(struct nfsd_readdirres *resp, u32 offset); +int nfs2svc_encode_entry(void *data, const char *name, int namlen, + loff_t offset, u64 ino, unsigned int d_type); int nfssvc_encode_entry(void *, const char *name, int namlen, loff_t offset, u64 ino, unsigned int);