From 832738e4b325b742940761e10487403f9aad13e8 Mon Sep 17 00:00:00 2001 From: Sergey Bashirov Date: Mon, 21 Jul 2025 17:48:55 +0300 Subject: [PATCH] NFSD: Rework encoding and decoding of nfsd4_deviceid Compilers may optimize the layout of C structures, so we should not rely on sizeof struct and memcpy to encode and decode XDR structures. The byte order of the fields should also be taken into account. This patch adds the correct functions to handle the deviceid4 structure and removes the pad field, which is currently not used by NFSD, from the runtime state. The server's byte order is preserved because the deviceid4 blob on the wire is only used as a cookie by the client. Signed-off-by: Sergey Bashirov Signed-off-by: Chuck Lever --- fs/nfsd/blocklayoutxdr.c | 7 ++----- fs/nfsd/flexfilelayoutxdr.c | 3 +-- fs/nfsd/nfs4layouts.c | 1 - fs/nfsd/nfs4xdr.c | 14 +------------- fs/nfsd/xdr4.h | 36 +++++++++++++++++++++++++++++++++++- 5 files changed, 39 insertions(+), 22 deletions(-) diff --git a/fs/nfsd/blocklayoutxdr.c b/fs/nfsd/blocklayoutxdr.c index bcf21fde9120..18de37ff2891 100644 --- a/fs/nfsd/blocklayoutxdr.c +++ b/fs/nfsd/blocklayoutxdr.c @@ -29,8 +29,7 @@ nfsd4_block_encode_layoutget(struct xdr_stream *xdr, *p++ = cpu_to_be32(len); *p++ = cpu_to_be32(1); /* we always return a single extent */ - p = xdr_encode_opaque_fixed(p, &b->vol_id, - sizeof(struct nfsd4_deviceid)); + p = svcxdr_encode_deviceid4(p, &b->vol_id); p = xdr_encode_hyper(p, b->foff); p = xdr_encode_hyper(p, b->len); p = xdr_encode_hyper(p, b->soff); @@ -156,9 +155,7 @@ nfsd4_block_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp, for (i = 0; i < nr_iomaps; i++) { struct pnfs_block_extent bex; - memcpy(&bex.vol_id, p, sizeof(struct nfsd4_deviceid)); - p += XDR_QUADLEN(sizeof(struct nfsd4_deviceid)); - + p = svcxdr_decode_deviceid4(p, &bex.vol_id); p = xdr_decode_hyper(p, &bex.foff); if (bex.foff & (block_size - 1)) { goto fail; diff --git a/fs/nfsd/flexfilelayoutxdr.c b/fs/nfsd/flexfilelayoutxdr.c index aeb71c10ff1b..f9f7e38cba13 100644 --- a/fs/nfsd/flexfilelayoutxdr.c +++ b/fs/nfsd/flexfilelayoutxdr.c @@ -54,8 +54,7 @@ nfsd4_ff_encode_layoutget(struct xdr_stream *xdr, *p++ = cpu_to_be32(1); /* single mirror */ *p++ = cpu_to_be32(1); /* single data server */ - p = xdr_encode_opaque_fixed(p, &fl->deviceid, - sizeof(struct nfsd4_deviceid)); + p = svcxdr_encode_deviceid4(p, &fl->deviceid); *p++ = cpu_to_be32(1); /* efficiency */ diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c index aea905fcaf87..683bd1130afe 100644 --- a/fs/nfsd/nfs4layouts.c +++ b/fs/nfsd/nfs4layouts.c @@ -120,7 +120,6 @@ nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp, id->fsid_idx = fhp->fh_export->ex_devid_map->idx; id->generation = device_generation; - id->pad = 0; return 0; } diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index ea91bad4eee2..2acc9abee668 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -587,18 +587,6 @@ nfsd4_decode_state_owner4(struct nfsd4_compoundargs *argp, } #ifdef CONFIG_NFSD_PNFS -static __be32 -nfsd4_decode_deviceid4(struct nfsd4_compoundargs *argp, - struct nfsd4_deviceid *devid) -{ - __be32 *p; - - p = xdr_inline_decode(argp->xdr, NFS4_DEVICEID4_SIZE); - if (!p) - return nfserr_bad_xdr; - memcpy(devid, p, sizeof(*devid)); - return nfs_ok; -} static __be32 nfsd4_decode_layoutupdate4(struct nfsd4_compoundargs *argp, @@ -1783,7 +1771,7 @@ nfsd4_decode_getdeviceinfo(struct nfsd4_compoundargs *argp, __be32 status; memset(gdev, 0, sizeof(*gdev)); - status = nfsd4_decode_deviceid4(argp, &gdev->gd_devid); + status = nfsd4_decode_deviceid4(argp->xdr, &gdev->gd_devid); if (status) return status; if (xdr_stream_decode_u32(argp->xdr, &gdev->gd_layout_type) < 0) diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h index a23bc56051ca..e65b552bf5f5 100644 --- a/fs/nfsd/xdr4.h +++ b/fs/nfsd/xdr4.h @@ -595,9 +595,43 @@ struct nfsd4_reclaim_complete { struct nfsd4_deviceid { u64 fsid_idx; u32 generation; - u32 pad; }; +static inline __be32 * +svcxdr_encode_deviceid4(__be32 *p, const struct nfsd4_deviceid *devid) +{ + __be64 *q = (__be64 *)p; + + *q = (__force __be64)devid->fsid_idx; + p += 2; + *p++ = (__force __be32)devid->generation; + *p++ = xdr_zero; + return p; +} + +static inline __be32 * +svcxdr_decode_deviceid4(__be32 *p, struct nfsd4_deviceid *devid) +{ + __be64 *q = (__be64 *)p; + + devid->fsid_idx = (__force u64)(*q); + p += 2; + devid->generation = (__force u32)(*p++); + p++; /* NFSD does not use the remaining octets */ + return p; +} + +static inline __be32 +nfsd4_decode_deviceid4(struct xdr_stream *xdr, struct nfsd4_deviceid *devid) +{ + __be32 *p = xdr_inline_decode(xdr, NFS4_DEVICEID4_SIZE); + + if (unlikely(!p)) + return nfserr_bad_xdr; + svcxdr_decode_deviceid4(p, devid); + return nfs_ok; +} + struct nfsd4_layout_seg { u32 iomode; u64 offset; -- 2.47.3