CIFS: Add oplock break support for SMB2

Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 74 insertions, 2 deletions

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 78225f517a60..01479a3fee8d 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -142,8 +142,8 @@ smb2_check_message(char *buf, unsigned int length)
         }
 
         if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
-                if (hdr->Status == 0 ||
-                    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2) {
+                if (command != SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0 ||
+                    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
                         /* error packets have 9 byte structure size */
                         cERROR(1, "Illegal response size %u for command %d",
                                    le16_to_cpu(pdu->StructureSize2), command);
@@ -162,6 +162,9 @@ smb2_check_message(char *buf, unsigned int length)
         if (4 + len != clc_len) {
                 cFYI(1, "Calculated size %u length %u mismatch mid %llu",
                         clc_len, 4 + len, mid);
+                /* Windows 7 server returns 24 bytes more */
+                if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
+                        return 0;
                 /* server can return one byte more */
                 if (clc_len == 4 + len + 1)
                         return 0;
@@ -356,3 +359,72 @@ cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
         return to;
 }
+
+bool
+smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
+{
+        struct smb2_oplock_break *rsp = (struct smb2_oplock_break *)buffer;
+        struct list_head *tmp, *tmp1, *tmp2;
+        struct cifs_ses *ses;
+        struct cifs_tcon *tcon;
+        struct cifsInodeInfo *cinode;
+        struct cifsFileInfo *cfile;
+
+        cFYI(1, "Checking for oplock break");
+
+        if (rsp->hdr.Command != SMB2_OPLOCK_BREAK)
+                return false;
+
+        if (le16_to_cpu(rsp->StructureSize) !=
+                                smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
+                return false;
+        }
+
+        cFYI(1, "oplock level 0x%d", rsp->OplockLevel);
+
+        /* look up tcon based on tid & uid */
+        spin_lock(&cifs_tcp_ses_lock);
+        list_for_each(tmp, &server->smb_ses_list) {
+                ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
+                list_for_each(tmp1, &ses->tcon_list) {
+                        tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
+
+                        cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
+                        spin_lock(&cifs_file_list_lock);
+                        list_for_each(tmp2, &tcon->openFileList) {
+                                cfile = list_entry(tmp2, struct cifsFileInfo,
+                                                     tlist);
+                                if (rsp->PersistentFid !=
+                                    cfile->fid.persistent_fid ||
+                                    rsp->VolatileFid !=
+                                    cfile->fid.volatile_fid)
+                                        continue;
+
+                                cFYI(1, "file id match, oplock break");
+                                cinode = CIFS_I(cfile->dentry->d_inode);
+
+                                if (!cinode->clientCanCacheAll &&
+                                    rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
+                                        cfile->oplock_break_cancelled = true;
+                                else
+                                        cfile->oplock_break_cancelled = false;
+
+                                smb2_set_oplock_level(cinode,
+                                  rsp->OplockLevel ? SMB2_OPLOCK_LEVEL_II : 0);
+
+                                queue_work(cifsiod_wq, &cfile->oplock_break);
+
+                                spin_unlock(&cifs_file_list_lock);
+                                spin_unlock(&cifs_tcp_ses_lock);
+                                return true;
+                        }
+                        spin_unlock(&cifs_file_list_lock);
+                        spin_unlock(&cifs_tcp_ses_lock);
+                        cFYI(1, "No matching file for oplock break");
+                        return true;
+                }
+        }
+        spin_unlock(&cifs_tcp_ses_lock);
+        cFYI(1, "Can not process oplock break for non-existent connection");
+        return false;
+}