[PATCH 1/3] NFSv4.2: Set the correct size scratch buffer for decoding READ_PLUS

[PATCH 1/3] NFSv4.2: Set the correct size scratch buffer for decoding READ_PLUS

[Anna Schumaker]

From: Anna Schumaker <Anna.Schumaker@Netapp.com>

The scratch_buf array is 16 bytes, but I was passing 32 to the
xdr_set_scratch_buffer() function. Fix this by using sizeof(), which is
what I probably should have been doing this whole time.

Fixes: d3b00a802c84 ("NFS: Replace the READ_PLUS decoding code")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/nfs42xdr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index fe1aeb0f048f..2fd465cab631 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -1142,7 +1142,7 @@ 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, 32);
+	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]);
-- 
2.38.1

[PATCH 2/3] NFSv4.2: Fix up READ_PLUS alignment

[Anna Schumaker]

From: Anna Schumaker <Anna.Schumaker@Netapp.com>

Assume that the first segment will be a DATA segment, and place the data
directly into the xdr pages so it doesn't need to be shifted.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/nfs42xdr.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index 2fd465cab631..d80ee88ca996 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -47,13 +47,14 @@
 #define decode_deallocate_maxsz		(op_decode_hdr_maxsz)
 #define encode_read_plus_maxsz		(op_encode_hdr_maxsz + \
 					 encode_stateid_maxsz + 3)
-#define NFS42_READ_PLUS_SEGMENT_SIZE	(1 /* data_content4 */ + \
+#define NFS42_READ_PLUS_DATA_SEGMENT_SIZE \
+					(1 /* data_content4 */ + \
 					 2 /* data_info4.di_offset */ + \
-					 2 /* data_info4.di_length */)
+					 1 /* data_info4.di_length */)
 #define decode_read_plus_maxsz		(op_decode_hdr_maxsz + \
 					 1 /* rpr_eof */ + \
 					 1 /* rpr_contents count */ + \
-					 2 * NFS42_READ_PLUS_SEGMENT_SIZE)
+					 NFS42_READ_PLUS_DATA_SEGMENT_SIZE)
 #define encode_seek_maxsz		(op_encode_hdr_maxsz + \
 					 encode_stateid_maxsz + \
 					 2 /* offset */ + \
-- 
2.38.1

[PATCH 3/3] NFSv4.2: Change the default KConfig value for READ_PLUS

[Anna Schumaker]

From: Anna Schumaker <Anna.Schumaker@Netapp.com>

Now that we've worked out performance issues and have a server patch
addressing the failed xfstests, we can safely enable this feature by
default.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/Kconfig | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 14a72224b657..1ead5bd740c2 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -209,8 +209,8 @@ config NFS_DISABLE_UDP_SUPPORT
 config NFS_V4_2_READ_PLUS
 	bool "NFS: Enable support for the NFSv4.2 READ_PLUS operation"
 	depends on NFS_V4_2
-	default n
+	default y
 	help
-	 This is intended for developers only. The READ_PLUS operation has
-	 been shown to have issues under specific conditions and should not
-	 be used in production.
+	 Choose Y here to enable the use of READ_PLUS over NFS v4.2. READ_PLUS
+	 attempts to improve read performance by compressing out sparse holes
+	 in the file contents.
-- 
2.38.1