[CIFS] Add posix (advisory) byte range locking support to cifs client

Samba (version 3) server support for this is also currently being
done.  This client code is in an experimental path (requires enabling
/proc/fs/cifs/Experimental) while it is being tested.

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 48 insertions, 19 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index e5bf1ad540d9..bd135c4e4958 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -577,13 +577,14 @@ int cifs_closedir(struct inode *inode, struct file *file)
 int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 {
         int rc, xid;
-        __u32 lockType = LOCKING_ANDX_LARGE_FILES;
         __u32 numLock = 0;
         __u32 numUnlock = 0;
         __u64 length;
         int wait_flag = FALSE;
         struct cifs_sb_info *cifs_sb;
         struct cifsTconInfo *pTcon;
+        __u16 netfid;
+        __u8 lockType = LOCKING_ANDX_LARGE_FILES;
 
         length = 1 + pfLock->fl_end - pfLock->fl_start;
         rc = -EACCES;
@@ -640,27 +641,39 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
                 FreeXid(xid);
                 return -EBADF;
         }
+        netfid = ((struct cifsFileInfo *)file->private_data)->netfid;
+
 
+        /* BB add code here to normalize offset and length to
+        account for negative length which we can not accept over the
+        wire */
         if (IS_GETLK(cmd)) {
-                rc = CIFSSMBLock(xid, pTcon,
-                                 ((struct cifsFileInfo *)file->
-                                  private_data)->netfid,
-                                 length,
-                                 pfLock->fl_start, 0, 1, lockType,
-                                 0 /* wait flag */ );
+                if(experimEnabled && 
+                   (cifs_sb->tcon->ses->capabilities & CAP_UNIX)) {
+                        int posix_lock_type;
+                        if(lockType & LOCKING_ANDX_SHARED_LOCK)
+                                posix_lock_type = CIFS_RDLCK;
+                        else
+                                posix_lock_type = CIFS_WRLCK;
+                        rc = CIFSSMBPosixLock(xid, pTcon, netfid, 1 /* get */,
+                                        length, pfLock->fl_start,
+                                        posix_lock_type, wait_flag);
+                        FreeXid(xid);
+                        return rc;
+                }
+
+                /* BB we could chain these into one lock request BB */
+                rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
+                                 0, 1, lockType, 0 /* wait flag */ );
                 if (rc == 0) {
-                        rc = CIFSSMBLock(xid, pTcon,
-                                         ((struct cifsFileInfo *) file->
-                                          private_data)->netfid,
-                                         length,
+                        rc = CIFSSMBLock(xid, pTcon, netfid, length, 
                                          pfLock->fl_start, 1 /* numUnlock */ ,
                                          0 /* numLock */ , lockType,
                                          0 /* wait flag */ );
                         pfLock->fl_type = F_UNLCK;
                         if (rc != 0)
                                 cERROR(1, ("Error unlocking previously locked "
-                                           "range %d during test of lock ",
-                                           rc));
+                                           "range %d during test of lock", rc));
                         rc = 0;
 
                 } else {
@@ -672,12 +685,28 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
                 FreeXid(xid);
                 return rc;
         }
-
-        rc = CIFSSMBLock(xid, pTcon,
-                         ((struct cifsFileInfo *) file->private_data)->
-                         netfid, length,
-                         pfLock->fl_start, numUnlock, numLock, lockType,
-                         wait_flag);
+        if (experimEnabled &&
+                (cifs_sb->tcon->ses->capabilities & CAP_UNIX)) {
+                int posix_lock_type;
+                if(lockType & LOCKING_ANDX_SHARED_LOCK)
+                        posix_lock_type = CIFS_RDLCK;
+                else
+                        posix_lock_type = CIFS_WRLCK;
+                
+                if(numUnlock == 1)
+                        posix_lock_type |= CIFS_UNLCK;
+                else if(numLock == 0) {
+                        /* if no lock or unlock then nothing
+                        to do since we do not know what it is */
+                        FreeXid(xid);
+                        return -EOPNOTSUPP;
+                }
+                rc = CIFSSMBPosixLock(xid, pTcon, netfid, 0 /* set */,
+                                      length, pfLock->fl_start,
+                                      posix_lock_type, wait_flag);
+        } else
+                rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
+                                numUnlock, numLock, lockType, wait_flag);
         if (pfLock->fl_flags & FL_POSIX)
                 posix_lock_file_wait(file, pfLock);
         FreeXid(xid);