[PATCH] Remove fcntl f_op

The newly introduced ->fcntl file_operation is badly thought out,
not to mention undocumented.  This patch replaces it with two better
defined operations -- check_flags and dir_notify.  Any other fcntl()s
that filesystems are interested in can have their own properly typed
f_op method when they need it.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/filesystems/Locking

@@ -349,6 +349,8 @@ prototypes:
 			loff_t *, int);
 	unsigned long (*get_unmapped_area)(struct file *, unsigned long,
 			unsigned long, unsigned long, unsigned long);
+	int (*check_flags)(int);
+	int (*dir_notify)(struct file *, unsigned long);
 };
 
 locking rules:
@@ -375,6 +377,8 @@ writev:			no
 sendfile:		no
 sendpage:		no
 get_unmapped_area:	no
+check_flags:		no
+dir_notify:		no
 
 ->llseek() locking has moved from llseek to the individual llseek
 implementations.  If your fs is not using generic_file_llseek, you

fs/cifs/cifsfs.c

@@ -534,18 +534,14 @@ struct file_operations cifs_file_ops = {
 	.flush = cifs_flush,
 	.mmap  = cifs_file_mmap,
 	.sendfile = generic_file_sendfile,
-#ifdef CONFIG_CIFS_FCNTL
-	.fcntl = cifs_fcntl,
-#endif
+	.dir_notify = cifs_dir_notify,
 };
 
 struct file_operations cifs_dir_ops = {
 	.readdir = cifs_readdir,
 	.release = cifs_closedir,
 	.read    = generic_read_dir,
-#ifdef CONFIG_CIFS_FCNTL
-	.fcntl   = cifs_fcntl,
-#endif
+	.dir_notify = cifs_dir_notify,
 };
 
 static void

fs/cifs/cifsfs.h

@@ -74,7 +74,7 @@ extern int cifs_file_mmap(struct file * , struct vm_area_struct *);
 extern struct file_operations cifs_dir_ops;
 extern int cifs_dir_open(struct inode *inode, struct file *file);
 extern int cifs_readdir(struct file *file, void *direntry, filldir_t filldir);
-extern long cifs_fcntl(int, unsigned int, unsigned long, struct file *);
+extern int cifs_dir_notify(struct file *, unsigned long arg);
 
 /* Functions related to dir entries */
 extern struct dentry_operations cifs_dentry_ops;

fs/cifs/fcntl.c

@@ -28,7 +28,7 @@
 #include "cifs_unicode.h"
 #include "cifs_debug.h"
 
-int cifs_directory_notify(unsigned long arg, struct file * file)
+int cifs_dir_notify(struct file * file, unsigned long arg)
 {
 	int xid;
 	int rc = -EINVAL;
@@ -70,53 +70,3 @@ int cifs_directory_notify(unsigned long arg, struct file * file)
 	FreeXid(xid);
 	return rc;
 }
-
-
-long cifs_fcntl(int file_desc, unsigned int command, unsigned long arg,
-				struct file * file)
-{
-	/* Few few file control functions need to be specially mapped. So far
-	only:
-		F_NOTIFY (for directory change notification)
-	And eventually:
-		F_GETLEASE
-		F_SETLEASE 
-	need to be mapped here. The others either already are mapped downstream
-	or do not need to go to the server (client only sideeffects):
-		F_DUPFD:
-		F_GETFD:
-		F_SETFD:
-		F_GETFL:
-		F_SETFL:
-		F_GETLK:
-		F_SETLK:
-		F_SETLKW:
-		F_GETOWN:
-		F_SETOWN:
-		F_GETSIG:
-		F_SETSIG:
-	*/
-	long rc = 0;
-
-	cFYI(1,("cifs_fcntl: command %d with arg %lx",command,arg)); /* BB removeme BB */
-
-	switch (command) {
-	case F_NOTIFY:
-		/* let the local call have a chance to fail first */
-		rc = generic_file_fcntl(file_desc,command,arg,file);
-		if(rc)
-			return rc;
-		else {
-			/* local call succeeded try to do remote notify to
-			pick up changes from other clients to server file */
-			cifs_directory_notify(arg, file);
-			/* BB add case to long and return rc from above */
-			return rc;
-		}
-		break;
-	default:
-		break;
-	}
-	return generic_file_fcntl(file_desc,command,arg,file);
-}
-                

fs/dnotify.c

@@ -104,6 +104,9 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
 	dn->dn_next = inode->i_dnotify;
 	inode->i_dnotify = dn;
 	spin_unlock(&inode->i_lock);
+
+	if (filp->f_op && filp->f_op->dir_notify)
+		return filp->f_op->dir_notify(filp, arg);
 	return 0;
 
 out_free:

fs/fcntl.c

@@ -239,6 +239,11 @@ static int setfl(int fd, struct file * filp, unsigned long arg)
 				return -EINVAL;
 	}
 
+	if (filp->f_op && filp->f_op->check_flags)
+		error = filp->f_op->check_flags(arg);
+	if (error)
+		return error;
+
 	lock_kernel();
 	if ((arg ^ filp->f_flags) & FASYNC) {
 		if (filp->f_op && filp->f_op->fasync) {
@@ -287,8 +292,8 @@ void f_delown(struct file *filp)
 
 EXPORT_SYMBOL(f_delown);
 
-long generic_file_fcntl(int fd, unsigned int cmd,
-			unsigned long arg, struct file *filp)
+static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
+		struct file *filp)
 {
 	long err = -EINVAL;
 
@@ -356,15 +361,6 @@ long generic_file_fcntl(int fd, unsigned int cmd,
 	}
 	return err;
 }
-EXPORT_SYMBOL(generic_file_fcntl);
-
-static long do_fcntl(int fd, unsigned int cmd,
-			unsigned long arg, struct file *filp)
-{
-	if (filp->f_op && filp->f_op->fcntl)
-		return filp->f_op->fcntl(fd, cmd, arg, filp);
-	return generic_file_fcntl(fd, cmd, arg, filp);
-}
 
 asmlinkage long sys_fcntl(int fd, unsigned int cmd, unsigned long arg)
 {	

fs/nfs/file.c

@@ -33,8 +33,6 @@
 
 #define NFSDBG_FACILITY		NFSDBG_FILE
 
-static long nfs_file_fcntl(int fd, unsigned int cmd,
-			unsigned long arg, struct file *filp);
 static int nfs_file_open(struct inode *, struct file *);
 static int nfs_file_release(struct inode *, struct file *);
 static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
@@ -43,6 +41,7 @@ static ssize_t nfs_file_read(struct kiocb *, char __user *, size_t, loff_t);
 static ssize_t nfs_file_write(struct kiocb *, const char __user *, size_t, loff_t);
 static int  nfs_file_flush(struct file *);
 static int  nfs_fsync(struct file *, struct dentry *dentry, int datasync);
+static int nfs_check_flags(int flags);
 
 struct file_operations nfs_file_operations = {
 	.llseek		= remote_llseek,
@@ -57,7 +56,7 @@ struct file_operations nfs_file_operations = {
 	.fsync		= nfs_fsync,
 	.lock		= nfs_lock,
 	.sendfile	= nfs_file_sendfile,
-	.fcntl		= nfs_file_fcntl,
+	.check_flags	= nfs_check_flags,
 };
 
 struct inode_operations nfs_file_inode_operations = {
@@ -71,26 +70,12 @@ struct inode_operations nfs_file_inode_operations = {
 # define IS_SWAPFILE(inode)	(0)
 #endif
 
-#define nfs_invalid_flags	(O_APPEND | O_DIRECT)
-
-/*
- * Check for special cases that NFS doesn't support, and
- * pass the rest to the generic fcntl function.
- */
-static long
-nfs_file_fcntl(int fd, unsigned int cmd,
-		unsigned long arg, struct file *filp)
+static int nfs_check_flags(int flags)
 {
-	switch (cmd) {
-	case F_SETFL:
-		if ((filp->f_flags & nfs_invalid_flags) == nfs_invalid_flags)
-			return -EINVAL;
-		break;
-	default:
-		break;
-	}
+	if (flags & (O_APPEND | O_DIRECT))
+		return -EINVAL;
 
-	return generic_file_fcntl(fd, cmd, arg, filp);
+	return 0;
 }
 
 /*
@@ -101,10 +86,11 @@ nfs_file_open(struct inode *inode, struct file *filp)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
 	int (*open)(struct inode *, struct file *);
-	int res = 0;
+	int res;
 
-	if ((filp->f_flags & nfs_invalid_flags) == nfs_invalid_flags)
-		return -EINVAL;
+	res = nfs_check_flags(filp->f_flags);
+	if (!res)
+		return res;
 
 	lock_kernel();
 	/* Do NFSv4 open() call */

include/linux/fs.h

@@ -665,9 +665,6 @@ extern struct list_head file_lock_list;
 
 #include <linux/fcntl.h>
 
-extern long generic_file_fcntl(int fd, unsigned int cmd,
-				unsigned long arg, struct file *filp);
-
 extern int fcntl_getlk(struct file *, struct flock __user *);
 extern int fcntl_setlk(struct file *, unsigned int, struct flock __user *);
 
@@ -895,8 +892,8 @@ struct file_operations {
 	ssize_t (*sendfile) (struct file *, loff_t *, size_t, read_actor_t, void *);
 	ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
 	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
-	long (*fcntl)(int fd, unsigned int cmd,
-			unsigned long arg, struct file *filp);
+	int (*check_flags)(int);
+	int (*dir_notify)(struct file *filp, unsigned long arg);
 };
 
 struct inode_operations {