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| author | Chuck Lever <chuck.lever@oracle.com> | 2024-12-31 03:28:56 +0300 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2025-01-11 07:43:25 +0300 |
| commit | 4163ee711cf141ada9e884a94e6e329431547fd7 (patch) | |
| tree | 32a10cbf3bea92ea7705a4b3a787e99c866a7b43 /fs/nfsd/nfs4xdr.c | |
| parent | b786caa65d4baa73257487e27ebab9004dc768d1 (diff) | |
| download | linux-4163ee711cf141ada9e884a94e6e329431547fd7.tar.xz | |
NFSD: Insulate nfsd4_encode_fattr4() from page boundaries in the encode buffer
Commit ab04de60ae1c ("NFSD: Optimize nfsd4_encode_fattr()") replaced
the use of write_bytes_to_xdr_buf() because it's expensive and the
data items to be encoded are already properly aligned.
However, there's no guarantee that the pointer returned from
xdr_reserve_space() will still point to the correct reserved space
in the encode buffer after one or more intervening calls to
xdr_reserve_space(). It just happens to work with the current
implementation of xdr_reserve_space().
This commit effectively reverts the optimization.
Reviewed-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfsd/nfs4xdr.c')
| -rw-r--r-- | fs/nfsd/nfs4xdr.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index ae4c6c0060bf..8d373d2edff1 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -3507,8 +3507,8 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct nfsd4_fattr_args args; struct svc_fh *tempfh = NULL; int starting_len = xdr->buf->len; - __be32 *attrlen_p, status; - int attrlen_offset; + unsigned int attrlen_offset; + __be32 attrlen, status; u32 attrmask[3]; int err; struct nfsd4_compoundres *resp = rqstp->rq_resp; @@ -3629,8 +3629,7 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr, /* attr_vals */ attrlen_offset = xdr->buf->len; - attrlen_p = xdr_reserve_space(xdr, XDR_UNIT); - if (!attrlen_p) + if (unlikely(!xdr_reserve_space(xdr, XDR_UNIT))) goto out_resource; bitmap_from_arr32(attr_bitmap, attrmask, ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops)); @@ -3640,7 +3639,8 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr, if (status != nfs_ok) goto out; } - *attrlen_p = cpu_to_be32(xdr->buf->len - attrlen_offset - XDR_UNIT); + attrlen = cpu_to_be32(xdr->buf->len - attrlen_offset - XDR_UNIT); + write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, XDR_UNIT); status = nfs_ok; out: |