CIFS: Request SMB2.1 leases

if server supports them and we need oplocks.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

8 files changed, 256 insertions, 27 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 4cd68c77ce3..28ac048d54e 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -36,6 +36,7 @@
 #include <linux/kthread.h>
 #include <linux/freezer.h>
 #include <linux/namei.h>
+#include <linux/random.h>
 #include <net/ipv6.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
@@ -88,6 +89,10 @@ extern mempool_t *cifs_mid_poolp;
 
 struct workqueue_struct *cifsiod_wq;
 
+#ifdef CONFIG_CIFS_SMB2
+__u8 cifs_client_guid[SMB2_CLIENT_GUID_SIZE];
+#endif
+
 static int
 cifs_read_super(struct super_block *sb)
 {
@@ -218,9 +223,10 @@ cifs_alloc_inode(struct super_block *sb)
                 return NULL;
         cifs_inode->cifsAttrs = 0x20;   /* default */
         cifs_inode->time = 0;
-        /* Until the file is open and we have gotten oplock
-        info back from the server, can not assume caching of
-        file data or metadata */
+        /*
+         * Until the file is open and we have gotten oplock info back from the
+         * server, can not assume caching of file data or metadata.
+         */
         cifs_set_oplock_level(cifs_inode, 0);
         cifs_inode->delete_pending = false;
         cifs_inode->invalid_mapping = false;
@@ -228,10 +234,14 @@ cifs_alloc_inode(struct super_block *sb)
         cifs_inode->server_eof = 0;
         cifs_inode->uniqueid = 0;
         cifs_inode->createtime = 0;
-
-        /* Can not set i_flags here - they get immediately overwritten
-           to zero by the VFS */
-/*      cifs_inode->vfs_inode.i_flags = S_NOATIME | S_NOCMTIME;*/
+#ifdef CONFIG_CIFS_SMB2
+        get_random_bytes(cifs_inode->lease_key, SMB2_LEASE_KEY_SIZE);
+#endif
+        /*
+         * Can not set i_flags here - they get immediately overwritten to zero
+         * by the VFS.
+         */
+        /* cifs_inode->vfs_inode.i_flags = S_NOATIME | S_NOCMTIME; */
         INIT_LIST_HEAD(&cifs_inode->openFileList);
         INIT_LIST_HEAD(&cifs_inode->llist);
         return &cifs_inode->vfs_inode;
@@ -1107,6 +1117,10 @@ init_cifs(void)
         spin_lock_init(&cifs_file_list_lock);
         spin_lock_init(&GlobalMid_Lock);
 
+#ifdef CONFIG_CIFS_SMB2
+        get_random_bytes(cifs_client_guid, SMB2_CLIENT_GUID_SIZE);
+#endif
+
         if (cifs_max_pending < 2) {
                 cifs_max_pending = 2;
                 cFYI(1, "cifs_max_pending set to min of 2");
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index e2492e1cdb8..b6ec142028e 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -361,6 +361,12 @@ struct smb_version_operations {
                                  const unsigned int);
         /* push brlocks from the cache to the server */
         int (*push_mand_locks)(struct cifsFileInfo *);
+        /* get lease key of the inode */
+        void (*get_lease_key)(struct inode *, struct cifs_fid *fid);
+        /* set lease key of the inode */
+        void (*set_lease_key)(struct inode *, struct cifs_fid *fid);
+        /* generate new lease key */
+        void (*new_lease_key)(struct cifs_fid *fid);
 };
 
 struct smb_version_values {
@@ -895,6 +901,7 @@ struct cifs_fid {
 #ifdef CONFIG_CIFS_SMB2
         __u64 persistent_fid;   /* persist file id for smb2 */
         __u64 volatile_fid;     /* volatile file id for smb2 */
+        __u8 lease_key[SMB2_LEASE_KEY_SIZE];    /* lease key for smb2 */
 #endif
 };
 
@@ -1012,6 +1019,9 @@ struct cifsInodeInfo {
         u64  server_eof;                /* current file size on server -- protected by i_lock */
         u64  uniqueid;                  /* server inode number */
         u64  createtime;                /* creation time on server */
+#ifdef CONFIG_CIFS_SMB2
+        __u8 lease_key[SMB2_LEASE_KEY_SIZE];    /* lease key for this inode */
+#endif
 #ifdef CONFIG_CIFS_FSCACHE
         struct fscache_cookie *fscache;
 #endif
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index b99a1670dad..4f2147c5adb 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -340,6 +340,8 @@ cifs_create_get_file_info:
                 rc = cifs_get_inode_info(&newinode, full_path, buf, inode->i_sb,
                                          xid, &fid->netfid);
                 if (newinode) {
+                        if (server->ops->set_lease_key)
+                                server->ops->set_lease_key(newinode, fid);
                         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM)
                                 newinode->i_mode = mode;
                         if ((*oplock & CIFS_CREATE_ACTION) &&
@@ -418,6 +420,9 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
         tcon = tlink_tcon(tlink);
         server = tcon->ses->server;
 
+        if (server->ops->new_lease_key)
+                server->ops->new_lease_key(&fid);
+
         rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
                             &oplock, &fid, opened);
 
@@ -473,10 +478,14 @@ int cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
         if (IS_ERR(tlink))
                 goto out_free_xid;
 
-        rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
-                            &oplock, &fid, &created);
         tcon = tlink_tcon(tlink);
         server = tcon->ses->server;
+
+        if (server->ops->new_lease_key)
+                server->ops->new_lease_key(&fid);
+
+        rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
+                            &oplock, &fid, &created);
         if (!rc && server->ops->close)
                 server->ops->close(xid, tcon, &fid);
 
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 2e2e4f9aeb6..ccad858d2d6 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -177,8 +177,9 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
         int disposition;
         int create_options = CREATE_NOT_DIR;
         FILE_ALL_INFO *buf;
+        struct TCP_Server_Info *server = tcon->ses->server;
 
-        if (!tcon->ses->server->ops->open)
+        if (!server->ops->open)
                 return -ENOSYS;
 
         desired_access = cifs_convert_flags(f_flags);
@@ -218,9 +219,9 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
         if (backup_cred(cifs_sb))
                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 
-        rc = tcon->ses->server->ops->open(xid, tcon, full_path, disposition,
-                                          desired_access, create_options, fid,
-                                          oplock, buf, cifs_sb);
+        rc = server->ops->open(xid, tcon, full_path, disposition,
+                               desired_access, create_options, fid, oplock, buf,
+                               cifs_sb);
 
         if (rc)
                 goto out;
@@ -372,6 +373,7 @@ int cifs_open(struct inode *inode, struct file *file)
         unsigned int xid;
         __u32 oplock;
         struct cifs_sb_info *cifs_sb;
+        struct TCP_Server_Info *server;
         struct cifs_tcon *tcon;
         struct tcon_link *tlink;
         struct cifsFileInfo *cfile = NULL;
@@ -388,6 +390,7 @@ int cifs_open(struct inode *inode, struct file *file)
                 return PTR_ERR(tlink);
         }
         tcon = tlink_tcon(tlink);
+        server = tcon->ses->server;
 
         full_path = build_path_from_dentry(file->f_path.dentry);
         if (full_path == NULL) {
@@ -432,6 +435,9 @@ int cifs_open(struct inode *inode, struct file *file)
         }
 
         if (!posix_open_ok) {
+                if (server->ops->get_lease_key)
+                        server->ops->get_lease_key(inode, &fid);
+
                 rc = cifs_nt_open(full_path, inode, cifs_sb, tcon,
                                   file->f_flags, &oplock, &fid, xid);
                 if (rc)
@@ -440,8 +446,8 @@ int cifs_open(struct inode *inode, struct file *file)
 
         cfile = cifs_new_fileinfo(&fid, file, tlink, oplock);
         if (cfile == NULL) {
-                if (tcon->ses->server->ops->close)
-                        tcon->ses->server->ops->close(xid, tcon, &fid);
+                if (server->ops->close)
+                        server->ops->close(xid, tcon, &fid);
                 rc = -ENOMEM;
                 goto out;
         }
@@ -567,6 +573,9 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
         if (backup_cred(cifs_sb))
                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 
+        if (server->ops->get_lease_key)
+                server->ops->get_lease_key(inode, &fid);
+
         /*
          * Can not refresh inode by passing in file_info buf to be returned by
          * CIFSSMBOpen and then calling get_inode_info with returned buf since
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index 0ddd617ffa1..78fb2050e0d 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -63,6 +63,7 @@ smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
         int rc;
         __le16 *smb2_path;
         struct smb2_file_all_info *smb2_data = NULL;
+        __u8 smb2_oplock[17];
 
         smb2_path = cifs_convert_path_to_utf16(path, cifs_sb);
         if (smb2_path == NULL) {
@@ -78,11 +79,14 @@ smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
         }
 
         desired_access |= FILE_READ_ATTRIBUTES;
-        *oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;
+        *smb2_oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;
+
+        if (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
+                memcpy(smb2_oplock + 1, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 
         rc = SMB2_open(xid, tcon, smb2_path, &fid->persistent_fid,
                        &fid->volatile_fid, desired_access, disposition,
-                       0, 0, (__u8 *)oplock, smb2_data);
+                       0, 0, smb2_oplock, smb2_data);
         if (rc)
                 goto out;
 
@@ -99,6 +103,7 @@ smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
                 move_smb2_info_to_cifs(buf, smb2_data);
         }
 
+        *oplock = *smb2_oplock;
 out:
         kfree(smb2_data);
         kfree(smb2_path);
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 0808b238219..360d9079af4 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -555,6 +555,24 @@ smb2_mand_lock(const unsigned int xid, struct cifsFileInfo *cfile, __u64 offset,
                          current->tgid, length, offset, type, wait);
 }
 
+static void
+smb2_get_lease_key(struct inode *inode, struct cifs_fid *fid)
+{
+        memcpy(fid->lease_key, CIFS_I(inode)->lease_key, SMB2_LEASE_KEY_SIZE);
+}
+
+static void
+smb2_set_lease_key(struct inode *inode, struct cifs_fid *fid)
+{
+        memcpy(CIFS_I(inode)->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
+}
+
+static void
+smb2_new_lease_key(struct cifs_fid *fid)
+{
+        get_random_bytes(fid->lease_key, SMB2_LEASE_KEY_SIZE);
+}
+
 struct smb_version_operations smb21_operations = {
         .compare_fids = smb2_compare_fids,
         .setup_request = smb2_setup_request,
@@ -616,6 +634,9 @@ struct smb_version_operations smb21_operations = {
         .mand_lock = smb2_mand_lock,
         .mand_unlock_range = smb2_unlock_range,
         .push_mand_locks = smb2_push_mandatory_locks,
+        .get_lease_key = smb2_get_lease_key,
+        .set_lease_key = smb2_set_lease_key,
+        .new_lease_key = smb2_new_lease_key,
 };
 
 struct smb_version_values smb21_values = {
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index d3e1cfca337..89d2824587b 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -304,7 +304,7 @@ free_rsp_buf(int resp_buftype, void *rsp)
                 cifs_buf_release(rsp);
 }
 
-#define SMB2_NUM_PROT 1
+#define SMB2_NUM_PROT 2
 
 #define SMB2_PROT   0
 #define SMB21_PROT  1
@@ -393,6 +393,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 
         req->Capabilities = cpu_to_le32(SMB2_GLOBAL_CAP_DFS);
 
+        memcpy(req->ClientGUID, cifs_client_guid, SMB2_CLIENT_GUID_SIZE);
+
         iov[0].iov_base = (char *)req;
         /* 4 for rfc1002 length field */
         iov[0].iov_len = get_rfc1002_length(req) + 4;
@@ -868,6 +870,83 @@ SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon)
         return rc;
 }
 
+static struct create_lease *
+create_lease_buf(u8 *lease_key, u8 oplock)
+{
+        struct create_lease *buf;
+
+        buf = kmalloc(sizeof(struct create_lease), GFP_KERNEL);
+        if (!buf)
+                return NULL;
+
+        memset(buf, 0, sizeof(struct create_lease));
+
+        buf->lcontext.LeaseKeyLow = cpu_to_le64(*((u64 *)lease_key));
+        buf->lcontext.LeaseKeyHigh = cpu_to_le64(*((u64 *)(lease_key + 8)));
+        if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE)
+                buf->lcontext.LeaseState = SMB2_LEASE_WRITE_CACHING |
+                                           SMB2_LEASE_READ_CACHING;
+        else if (oplock == SMB2_OPLOCK_LEVEL_II)
+                buf->lcontext.LeaseState = SMB2_LEASE_READ_CACHING;
+        else if (oplock == SMB2_OPLOCK_LEVEL_BATCH)
+                buf->lcontext.LeaseState = SMB2_LEASE_HANDLE_CACHING |
+                                           SMB2_LEASE_READ_CACHING |
+                                           SMB2_LEASE_WRITE_CACHING;
+
+        buf->ccontext.DataOffset = cpu_to_le16(offsetof
+                                        (struct create_lease, lcontext));
+        buf->ccontext.DataLength = cpu_to_le32(sizeof(struct lease_context));
+        buf->ccontext.NameOffset = cpu_to_le16(offsetof
+                                (struct create_lease, Name));
+        buf->ccontext.NameLength = cpu_to_le16(4);
+        buf->Name[0] = 'R';
+        buf->Name[1] = 'q';
+        buf->Name[2] = 'L';
+        buf->Name[3] = 's';
+        return buf;
+}
+
+static __u8
+parse_lease_state(struct smb2_create_rsp *rsp)
+{
+        char *data_offset;
+        struct create_lease *lc;
+        __u8 oplock = 0;
+        bool found = false;
+
+        data_offset = (char *)rsp;
+        data_offset += 4 + le32_to_cpu(rsp->CreateContextsOffset);
+        lc = (struct create_lease *)data_offset;
+        do {
+                char *name = le16_to_cpu(lc->ccontext.NameOffset) + (char *)lc;
+                if (le16_to_cpu(lc->ccontext.NameLength) != 4 ||
+                    strncmp(name, "RqLs", 4)) {
+                        lc = (struct create_lease *)((char *)lc
+                                        + le32_to_cpu(lc->ccontext.Next));
+                        continue;
+                }
+                if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
+                        return SMB2_OPLOCK_LEVEL_NOCHANGE;
+                found = true;
+                break;
+        } while (le32_to_cpu(lc->ccontext.Next) != 0);
+
+        if (!found)
+                return oplock;
+
+        if (le32_to_cpu(lc->lcontext.LeaseState) & SMB2_LEASE_WRITE_CACHING) {
+                if (le32_to_cpu(lc->lcontext.LeaseState) &
+                                                SMB2_LEASE_HANDLE_CACHING)
+                        oplock = SMB2_OPLOCK_LEVEL_BATCH;
+                else
+                        oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;
+        } else if (le32_to_cpu(lc->lcontext.LeaseState) &
+                                                SMB2_LEASE_READ_CACHING)
+                oplock = SMB2_OPLOCK_LEVEL_II;
+
+        return oplock;
+}
+
 int
 SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
           u64 *persistent_fid, u64 *volatile_fid, __u32 desired_access,
@@ -878,9 +957,11 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
         struct smb2_create_rsp *rsp;
         struct TCP_Server_Info *server;
         struct cifs_ses *ses = tcon->ses;
-        struct kvec iov[2];
+        struct kvec iov[3];
         int resp_buftype;
         int uni_path_len;
+        __le16 *copy_path = NULL;
+        int copy_size;
         int rc = 0;
         int num_iovecs = 2;
 
@@ -895,10 +976,6 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
         if (rc)
                 return rc;
 
-        if (server->oplocks)
-                req->RequestedOplockLevel = *oplock;
-        else
-                req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_NONE;
         req->ImpersonationLevel = IL_IMPERSONATION;
         req->DesiredAccess = cpu_to_le32(desired_access);
         /* File attributes ignored on open (used in create though) */
@@ -908,7 +985,7 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
         req->CreateOptions = cpu_to_le32(create_options);
         uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;
         req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req)
-                        - 1 /* pad */ - 4 /* do not count rfc1001 len field */);
+                        - 8 /* pad */ - 4 /* do not count rfc1001 len field */);
 
         iov[0].iov_base = (char *)req;
         /* 4 for rfc1002 length field */
@@ -919,6 +996,20 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
                 req->NameLength = cpu_to_le16(uni_path_len - 2);
                 /* -1 since last byte is buf[0] which is sent below (path) */
                 iov[0].iov_len--;
+                if (uni_path_len % 8 != 0) {
+                        copy_size = uni_path_len / 8 * 8;
+                        if (copy_size < uni_path_len)
+                                copy_size += 8;
+
+                        copy_path = kzalloc(copy_size, GFP_KERNEL);
+                        if (!copy_path)
+                                return -ENOMEM;
+                        memcpy((char *)copy_path, (const char *)path,
+                                uni_path_len);
+                        uni_path_len = copy_size;
+                        path = copy_path;
+                }
+
                 iov[1].iov_len = uni_path_len;
                 iov[1].iov_base = path;
                 /*
@@ -927,10 +1018,37 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
                  */
                 inc_rfc1001_len(req, uni_path_len - 1);
         } else {
+                iov[0].iov_len += 7;
+                req->hdr.smb2_buf_length = cpu_to_be32(be32_to_cpu(
+                                req->hdr.smb2_buf_length) + 8 - 1);
                 num_iovecs = 1;
                 req->NameLength = 0;
         }
 
+        if (!server->oplocks)
+                *oplock = SMB2_OPLOCK_LEVEL_NONE;
+
+        if (!(tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING) ||
+            *oplock == SMB2_OPLOCK_LEVEL_NONE)
+                req->RequestedOplockLevel = *oplock;
+        else {
+                iov[num_iovecs].iov_base = create_lease_buf(oplock+1, *oplock);
+                if (iov[num_iovecs].iov_base == NULL) {
+                        cifs_small_buf_release(req);
+                        kfree(copy_path);
+                        return -ENOMEM;
+                }
+                iov[num_iovecs].iov_len = sizeof(struct create_lease);
+                req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_LEASE;
+                req->CreateContextsOffset = cpu_to_le32(
+                        sizeof(struct smb2_create_req) - 4 - 8 +
+                        iov[num_iovecs-1].iov_len);
+                req->CreateContextsLength = cpu_to_le32(
+                        sizeof(struct create_lease));
+                inc_rfc1001_len(&req->hdr, sizeof(struct create_lease));
+                num_iovecs++;
+        }
+
         rc = SendReceive2(xid, ses, iov, num_iovecs, &resp_buftype, 0);
         rsp = (struct smb2_create_rsp *)iov[0].iov_base;
 
@@ -955,8 +1073,12 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
                 buf->DeletePending = 0;
         }
 
-        *oplock = rsp->OplockLevel;
+        if (rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE)
+                *oplock = parse_lease_state(rsp);
+        else
+                *oplock = rsp->OplockLevel;
 creat_exit:
+        kfree(copy_path);
         free_rsp_buf(resp_buftype, rsp);
         return rc;
 }
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 889ee5e193d..e818a5cc5bd 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -150,6 +150,10 @@ struct smb2_err_rsp {
         __u8   ErrorData[1];  /* variable length */
 } __packed;
 
+#define SMB2_CLIENT_GUID_SIZE 16
+
+extern __u8 cifs_client_guid[SMB2_CLIENT_GUID_SIZE];
+
 struct smb2_negotiate_req {
         struct smb2_hdr hdr;
         __le16 StructureSize; /* Must be 36 */
@@ -157,7 +161,7 @@ struct smb2_negotiate_req {
         __le16 SecurityMode;
         __le16 Reserved;        /* MBZ */
         __le32 Capabilities;
-        __u8   ClientGUID[16];  /* MBZ */
+        __u8   ClientGUID[SMB2_CLIENT_GUID_SIZE];
         __le64 ClientStartTime; /* MBZ */
         __le16 Dialects[2]; /* variable length */
 } __packed;
@@ -307,6 +311,8 @@ struct smb2_tree_disconnect_rsp {
 #define SMB2_OPLOCK_LEVEL_EXCLUSIVE     0x08
 #define SMB2_OPLOCK_LEVEL_BATCH         0x09
 #define SMB2_OPLOCK_LEVEL_LEASE         0xFF
+/* Non-spec internal type */
+#define SMB2_OPLOCK_LEVEL_NOCHANGE      0x99
 
 /* Desired Access Flags */
 #define FILE_READ_DATA_LE               cpu_to_le32(0x00000001)
@@ -404,7 +410,7 @@ struct smb2_create_req {
         __le16 NameLength;
         __le32 CreateContextsOffset;
         __le32 CreateContextsLength;
-        __u8   Buffer[1];
+        __u8   Buffer[8];
 } __packed;
 
 struct smb2_create_rsp {
@@ -428,6 +434,39 @@ struct smb2_create_rsp {
         __u8   Buffer[1];
 } __packed;
 
+struct create_context {
+        __le32 Next;
+        __le16 NameOffset;
+        __le16 NameLength;
+        __le16 Reserved;
+        __le16 DataOffset;
+        __le32 DataLength;
+        __u8 Buffer[0];
+} __packed;
+
+#define SMB2_LEASE_NONE                 __constant_cpu_to_le32(0x00)
+#define SMB2_LEASE_READ_CACHING         __constant_cpu_to_le32(0x01)
+#define SMB2_LEASE_HANDLE_CACHING       __constant_cpu_to_le32(0x02)
+#define SMB2_LEASE_WRITE_CACHING        __constant_cpu_to_le32(0x04)
+
+#define SMB2_LEASE_FLAG_BREAK_IN_PROGRESS __constant_cpu_to_le32(0x02)
+
+#define SMB2_LEASE_KEY_SIZE 16
+
+struct lease_context {
+        __le64 LeaseKeyLow;
+        __le64 LeaseKeyHigh;
+        __le32 LeaseState;
+        __le32 LeaseFlags;
+        __le64 LeaseDuration;
+} __packed;
+
+struct create_lease {
+        struct create_context ccontext;
+        __u8   Name[8];
+        struct lease_context lcontext;
+} __packed;
+
 /* Currently defined values for close flags */
 #define SMB2_CLOSE_FLAG_POSTQUERY_ATTRIB        cpu_to_le16(0x0001)
 struct smb2_close_req {