add direct mount options to optionally bypass the page cache on reads and writes

fs/cifs/README

@@ -115,11 +115,20 @@ cifs client, and that EA support is present in later versions of Samba (e.g.
 3.0.6 and later (also EA support works in all versions of Windows, at least to
 shares on NTFS filesystems).  Extended Attribute (xattr) support is an optional
 feature of most Linux filesystems which may require enabling via
-make menuconfig
+make menuconfig.
+
+The CIFS client can get and set POSIX ACLs (getfacl, setfacl) to Samba servers
+version 3.10 and later.  Setting POSIX ACLs requires enabling both XATTR and 
+then POSIX support in the CIFS configuration options when building the cifs
+module.
  
 Some administrators may want to change Samba's smb.conf "map archive" and 
-"create mask" parameters from the default.  Creating special devices (mknod) 
-remotely may require specifying a mkdev function to Samba if you are not using 
+"create mask" parameters from the default.  Unless the create mask is changed
+newly created files can end up with an unnecessarily restrictive default mode,
+which may not be what you want, although if the CIFS Unix extensions are
+enabled on the server and client, subsequent setattr calls (e.g. chmod) can
+fix the mode.  Note that creating special devices (mknod) remotely 
+may require specifying a mkdev function to Samba if you are not using 
 Samba 3.0.6 or later.  For more information on these see the manual pages
 ("man smb.conf") on the Samba server system.  Note that the cifs vfs,
 unlike the smbfs vfs, does not read the smb.conf on the client system 
@@ -324,6 +333,23 @@ A partial list of the supported mount options follows:
 		the client) set the uid and gid is the default. This
 		parameter has no effect if the CIFS Unix Extensions are not
 		negotiated.
+  netbiosname   When mounting to servers via port 139, specifies the RFC1001
+		source name to use to represent the client netbios machine 
+		name when doing the RFC1001 netbios session initialize.
+  direct        Do not do inode data caching on files opened on this mount.
+		This precludes mmaping files on this mount. In some cases
+		with fast networks and little or no caching benefits on the
+		client (e.g. when the application is doing large sequential
+		reads bigger than page size without rereading the same data) 
+		this can provide better performance than the default
+		behavior which caches reads (reaadahead) and writes 
+		(writebehind) through the local Linux client pagecache 
+		if oplock (caching token) is granted and held. Note that
+		direct allows write operations larger than page size
+		to be sent to the server.
+  acl   	Allow setfacl and getfacl to manage posix ACLs if server
+		supports them.  (default)
+  noacl 	Do not allow setfacl and getfacl calls on this mount
 		
 The mount.cifs mount helper also accepts a few mount options before -o
 including:
@@ -402,7 +428,7 @@ require enabling an ifdef (e.g. by  adding "#define CIFS_FCNTL" in cifsglob.h)
 	CONFIG_CIFS_FCNTL  (fcntl needed for support of directory change 
 			    notification and perhaps later for file leases)
 
-Per share (per client mount) statistics are available in /proc/fs/cifs/DebugData
+Per share (per client mount) statistics are available in /proc/fs/cifs/Stats
 if the kernel was configured with cifs statistics enabled.  The statistics
 represent the number of successful (ie non-zero return code from the server) 
 SMB responses to some of the more common commands (open, delete, mkdir etc.).

fs/cifs/cifs_fs_sb.h

 /*
  *   fs/cifs/cifs_fs_sb.h
  *
- *   Copyright (c) International Business Machines  Corp., 2002
+ *   Copyright (c) International Business Machines  Corp., 2002,2004
  *   Author(s): Steve French (sfrench@us.ibm.com)
  *
  *   This library is free software; you can redistribute it and/or modify
@@ -21,6 +21,7 @@
 #define CIFS_MOUNT_NO_PERM      1 /* do not do client vfs_perm check */
 #define CIFS_MOUNT_SET_UID      2 /* set current->euid in create etc. */
 #define CIFS_MOUNT_SERVER_INUM  4 /* inode numbers from uniqueid from server */
+#define CIFS_MOUNT_DIRECT_IO          8 /* do not write nor read through page cache */
 
 struct cifs_sb_info {
 	struct cifsTconInfo *tcon;	/* primary mount */

fs/cifs/cifsfs.c

@@ -435,6 +435,20 @@ cifs_read_wrapper(struct file * file, char __user *read_data, size_t read_size,
 		return -EIO;
 
 	cFYI(1,("In read_wrapper size %zd at %lld",read_size,*poffset));
+
+#ifdef CIFS_EXPERIMENTAL    /* BB fixme - fix user char * to kernel char * mapping here BB */
+	/* check whether we can cache writes locally */
+	if(file->f_dentry->d_sb) {
+		struct cifs_sb_info *cifs_sb;
+		cifs_sb = CIFS_SB(file->f_dentry->d_sb);
+		if(cifs_sb != NULL) {
+			if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO)
+				return cifs_read(file,read_data,
+							read_size,poffset);
+		}
+	}
+#endif /* CIFS_EXPERIMENTAL */
+
 	if(CIFS_I(file->f_dentry->d_inode)->clientCanCacheRead) {
 		return generic_file_read(file,read_data,read_size,poffset);
 	} else {
@@ -467,7 +481,18 @@ cifs_write_wrapper(struct file * file, const char __user *write_data,
 
 	cFYI(1,("In write_wrapper size %zd at %lld",write_size,*poffset));
 
+#ifdef CIFS_EXPERIMENTAL    /* BB fixme - fix user char * to kernel char * mapping here BB */
 	/* check whether we can cache writes locally */
+	if(file->f_dentry->d_sb) {
+		struct cifs_sb_info *cifs_sb;
+		cifs_sb = CIFS_SB(file->f_dentry->d_sb);
+		if(cifs_sb != NULL) {
+			if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO)
+				return cifs_write(file,write_data,
+							write_size,poffset);
+		}
+	}
+#endif /* CIFS_EXPERIMENTAL */
 	written = generic_file_write(file,write_data,write_size,poffset);
 	if(!CIFS_I(file->f_dentry->d_inode)->clientCanCacheAll)  {
 		if(file->f_dentry->d_inode->i_mapping) {

fs/cifs/connect.c

@@ -71,6 +71,7 @@ struct smb_vol {
 	unsigned noperm:1;
 	unsigned no_psx_acl:1; /* set if posix acl support should be disabled */
 	unsigned server_ino:1; /* use inode numbers from server ie UniqueId */
+	unsigned direct_io:1;
 	unsigned int rsize;
 	unsigned int wsize;
 	unsigned int sockopt;
@@ -792,6 +793,10 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
 			vol->no_psx_acl = 0;
 		} else if (strnicmp(data, "noacl",5) == 0) {
 			vol->no_psx_acl = 1;
+		} else if (strnicmp(data, "direct",6) == 0) {
+			vol->direct_io = 1;
+		} else if (strnicmp(data, "forcedirectio",13) == 0) {
+			vol->direct_io = 1;
 		} else if (strnicmp(data, "noac", 4) == 0) {
 			printk(KERN_WARNING "CIFS: Mount option noac not supported. Instead set /proc/fs/cifs/LookupCacheEnabled to 0\n");
 		} else
@@ -1407,6 +1412,10 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SET_UID;
 		if(volume_info.server_ino)
 			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SERVER_INUM;
+		if(volume_info.direct_io) {
+			cFYI(1,("mounting share using direct i/o"));
+			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
+		}
 
 		tcon =
 		    find_unc(sin_server.sin_addr.s_addr, volume_info.UNC,

fs/cifs/file.c

@@ -1067,6 +1067,17 @@ int cifs_file_mmap(struct file * file, struct vm_area_struct * vma)
 	struct dentry * dentry = file->f_dentry;
 	int	rc, xid;
 
+#ifdef CIFS_EXPERIMENTAL   /* BB fixme reenable when cifs_read_wrapper fixed */
+	if(dentry->d_sb) {
+		struct cifs_sb_info *cifs_sb;
+		cifs_sb = CIFS_SB(sb);
+		if(cifs_sb != NULL) {
+			if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO)
+				return -ENODEV
+		}
+	}
+#endif /* CIFS_EXPERIMENTAL */
+
 	xid = GetXid();
 	rc = cifs_revalidate(dentry);
 	if (rc) {