This is a note to let you know that I've just added the patch titled
NFSv4.2: Rework scratch handling for READ_PLUS
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsv4.2-rework-scratch-handling-for-read_plus.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 52845ff6959f19851197234a0663c28055e3e378
Author: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Date: Thu Apr 6 15:16:52 2023 -0400
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 <Anna.Schumaker@xxxxxxxxxx>
Stable-dep-of: bb05a617f06b ("NFSv4.2: Fix READ_PLUS smatch warnings")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index 2fd465cab631d..08c1dd094f010 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 1044305e77996..3f96ccc386c34 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 e86cf6642d212..2fd973d188c47 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 */
