From 886959f425b6a936a30b82a297ae3aecb3b8230f Mon Sep 17 00:00:00 2001 From: Anna Schumaker Date: Thu, 6 Apr 2023 15:16:52 -0400 Subject: [PATCH] NFSv4.2: Rework scratch handling for READ_PLUS [ Upstream commit fbd2a05f29a95d5b42b294bf47e55a711424965b ] Instead of using a tiny, static scratch buffer, we should use a kmalloc()-ed buffer that is allocated when checking for read plus usage. This lets us use the buffer before decoding any part of the READ_PLUS operation instead of setting it right before segment decoding, meaning it should be a little more robust. Signed-off-by: Anna Schumaker Stable-dep-of: bb05a617f06b ("NFSv4.2: Fix READ_PLUS smatch warnings") Signed-off-by: Sasha Levin --- fs/nfs/nfs42xdr.c | 4 ++-- fs/nfs/nfs4proc.c | 17 ++++++++++++----- include/linux/nfs_xdr.h | 1 + 3 files changed, 15 insertions(+), 7 deletions(-) diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c index 2fd465c..08c1dd0 100644 --- a/fs/nfs/nfs42xdr.c +++ b/fs/nfs/nfs42xdr.c @@ -1121,7 +1121,6 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res) uint32_t segments; struct read_plus_segment *segs; int status, i; - char scratch_buf[16]; __be32 *p; status = decode_op_hdr(xdr, OP_READ_PLUS); @@ -1142,7 +1141,6 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res) if (!segs) return -ENOMEM; - xdr_set_scratch_buffer(xdr, &scratch_buf, sizeof(scratch_buf)); status = -EIO; for (i = 0; i < segments; i++) { status = decode_read_plus_segment(xdr, &segs[i]); @@ -1347,6 +1345,8 @@ static int nfs4_xdr_dec_read_plus(struct rpc_rqst *rqstp, struct compound_hdr hdr; int status; + xdr_set_scratch_buffer(xdr, res->scratch, sizeof(res->scratch)); + status = decode_compound_hdr(xdr, &hdr); if (status) goto out; diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 1044305..3f96ccc 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -5446,6 +5446,8 @@ static bool nfs4_read_plus_not_supported(struct rpc_task *task, static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr) { + if (hdr->res.scratch) + kfree(hdr->res.scratch); if (!nfs4_sequence_done(task, &hdr->res.seq_res)) return -EAGAIN; if (nfs4_read_stateid_changed(task, &hdr->args)) @@ -5459,17 +5461,22 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr) } #if defined CONFIG_NFS_V4_2 && defined CONFIG_NFS_V4_2_READ_PLUS -static void nfs42_read_plus_support(struct nfs_pgio_header *hdr, +static bool nfs42_read_plus_support(struct nfs_pgio_header *hdr, struct rpc_message *msg) { /* Note: We don't use READ_PLUS with pNFS yet */ - if (nfs_server_capable(hdr->inode, NFS_CAP_READ_PLUS) && !hdr->ds_clp) + if (nfs_server_capable(hdr->inode, NFS_CAP_READ_PLUS) && !hdr->ds_clp) { msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ_PLUS]; + hdr->res.scratch = kmalloc(32, GFP_KERNEL); + return hdr->res.scratch != NULL; + } + return false; } #else -static void nfs42_read_plus_support(struct nfs_pgio_header *hdr, +static bool nfs42_read_plus_support(struct nfs_pgio_header *hdr, struct rpc_message *msg) { + return false; } #endif /* CONFIG_NFS_V4_2 */ @@ -5479,8 +5486,8 @@ static void nfs4_proc_read_setup(struct nfs_pgio_header *hdr, hdr->timestamp = jiffies; if (!hdr->pgio_done_cb) hdr->pgio_done_cb = nfs4_read_done_cb; - msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ]; - nfs42_read_plus_support(hdr, msg); + if (!nfs42_read_plus_support(hdr, msg)) + msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ]; nfs4_init_sequence(&hdr->args.seq_args, &hdr->res.seq_res, 0, 0); } diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h index e86cf66..2fd973d 100644 --- a/include/linux/nfs_xdr.h +++ b/include/linux/nfs_xdr.h @@ -670,6 +670,7 @@ struct nfs_pgio_res { struct { unsigned int replen; /* used by read */ int eof; /* used by read */ + void * scratch; /* used by read */ }; struct { struct nfs_writeverf * verf; /* used by write */ -- 2.7.4