[PATCH][CIFS] SMB2/SMB3 Copy offload support (refcopy) finishup

[Steve French]

>From 6474d967fc8228fff7579748f7219f6a8e443f30 Mon Sep 17 00:00:00 2001
From: Steve French <smfrench at gmail.com>
Date: Sat, 16 Nov 2013 01:06:00 -0600
Subject: [PATCH] CIFS: SMB2/SMB3 Copy offload support (refcopy) finish up

This patch extends the ability of copychunk (refcopy) to
handle servers with smaller than usual maximum chunk sizes
and also to handle files bigger than the maximum chunk sizes

Signed-off-by: Steve French <smfrench at gmail.com>
---
 fs/cifs/smb2ops.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++-------
 fs/cifs/smb2pdu.c |  2 +-
 2 files changed, 79 insertions(+), 12 deletions(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 11dde4b..7a21447 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -532,7 +532,10 @@ smb2_clone_range(const unsigned int xid,
     int rc;
     unsigned int ret_data_len;
     struct copychunk_ioctl *pcchunk;
-    char *retbuf = NULL;
+    struct copychunk_ioctl_rsp *retbuf = NULL;
+    struct cifs_tcon *tcon;
+    int chunks_copied = 0;
+    bool chunk_sizes_updated = false;

     pcchunk = kmalloc(sizeof(struct copychunk_ioctl), GFP_KERNEL);

@@ -552,22 +555,86 @@ smb2_clone_range(const unsigned int xid,
     /* For now array only one chunk long, will make more flexible later */
     pcchunk->ChunkCount = __constant_cpu_to_le32(1);
     pcchunk->Reserved = 0;
-    pcchunk->SourceOffset = cpu_to_le64(src_off);
-    pcchunk->TargetOffset = cpu_to_le64(dest_off);
-    pcchunk->Length = cpu_to_le32(len);
     pcchunk->Reserved2 = 0;

+    tcon = tlink_tcon(trgtfile->tlink);
+
+    while (len > 0) {
+        pcchunk->SourceOffset = cpu_to_le64(src_off);
+        pcchunk->TargetOffset = cpu_to_le64(dest_off);
+        pcchunk->Length =
+            cpu_to_le32(min_t(u32, len, tcon->max_bytes_chunk));
+
     /* Request that server copy to target from src file identified by key */
-    rc = SMB2_ioctl(xid, tlink_tcon(trgtfile->tlink),
-            trgtfile->fid.persistent_fid,
+        rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
             trgtfile->fid.volatile_fid, FSCTL_SRV_COPYCHUNK_WRITE,
             true /* is_fsctl */, (char *)pcchunk,
-            sizeof(struct copychunk_ioctl),    &retbuf, &ret_data_len);
-
-    /* BB need to special case rc = EINVAL to alter chunk size */
-
-    cifs_dbg(FYI, "rc %d data length out %d\n", rc, ret_data_len);
+            sizeof(struct copychunk_ioctl),    (char **)&retbuf,
+            &ret_data_len);
+        if (rc == 0) {
+            if (ret_data_len != sizeof(struct copychunk_ioctl_rsp))
+                goto cchunk_out;
+            if (retbuf->TotalBytesWritten == 0) {
+                cifs_dbg(FYI, "no bytes copied\n");
+                goto cchunk_out;
+            }
+            /*
+             * Check if server claimed to write more than we asked
+             */
+            if (le32_to_cpu(retbuf->TotalBytesWritten) >
+                le32_to_cpu(pcchunk->Length)) {
+                cifs_dbg(VFS, "invalid copy chunk response\n");
+                rc = -EIO;
+                goto cchunk_out;
+            }
+            if (le32_to_cpu(retbuf->ChunksWritten) != 1) {
+                cifs_dbg(VFS, "invalid num chunks written\n");
+                rc = -EIO;
+                goto cchunk_out;
+            }
+            chunks_copied++;
+
+            src_off += le32_to_cpu(retbuf->TotalBytesWritten);
+            dest_off += le32_to_cpu(retbuf->TotalBytesWritten);
+            len -= le32_to_cpu(retbuf->TotalBytesWritten);
+
+            cifs_dbg(FYI, "Chunks %d PartialChunk %d Total %d\n",
+                le32_to_cpu(retbuf->ChunksWritten),
+                le32_to_cpu(retbuf->ChunkBytesWritten),
+                le32_to_cpu(retbuf->TotalBytesWritten));
+        } else if (rc == -EINVAL) {
+            if (ret_data_len != sizeof(struct copychunk_ioctl_rsp))
+                goto cchunk_out;
+
+            cifs_dbg(FYI, "MaxChunks %d BytesChunk %d MaxCopy %d\n",
+                le32_to_cpu(retbuf->ChunksWritten),
+                le32_to_cpu(retbuf->ChunkBytesWritten),
+                le32_to_cpu(retbuf->TotalBytesWritten));
+
+            /*
+             * Check if this is the first request using these sizes,
+             * (ie check if copy succeed once with original sizes
+             * and check if the server gave us different sizes after
+             * we already updated max sizes on previous request).
+             * if not then why is the server returning an error now
+             */
+            if ((chunks_copied != 0) || chunk_sizes_updated)
+                goto cchunk_out;
+
+            /* Check that server is not asking us to grow size */
+            if (le32_to_cpu(retbuf->ChunkBytesWritten) <
+                    tcon->max_bytes_chunk)
+                tcon->max_bytes_chunk =
+                    le32_to_cpu(retbuf->ChunkBytesWritten);
+            else
+                goto cchunk_out; /* server gave us bogus size */
+
+            /* No need to change MaxChunks since already set to 1 */
+            chunk_sizes_updated = true;
+        }
+    }

+cchunk_out:
     kfree(pcchunk);
     return rc;
 }
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index d65270c..c5915dc 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1214,7 +1214,7 @@ SMB2_ioctl(const unsigned int xid, struct
cifs_tcon *tcon, u64 persistent_fid,
     rc = SendReceive2(xid, ses, iov, num_iovecs, &resp_buftype, 0);
     rsp = (struct smb2_ioctl_rsp *)iov[0].iov_base;

-    if (rc != 0) {
+    if ((rc != 0) && (rc != -EINVAL)) {
         if (tcon)
             cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
         goto ioctl_exit;
-- 
1.8.3.1


-- 
Thanks,

Steve
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