switch a bunch of places to mnt_want_write_file()

it's both faster (in case when file has been opened for write) and cleaner.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/btrfs/ioctl.c

@@ -201,7 +201,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 		}
 	}
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		goto out_unlock;
 
@@ -1855,7 +1855,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
 		goto out;
 	}
 
-	err = mnt_want_write(file->f_path.mnt);
+	err = mnt_want_write_file(file);
 	if (err)
 		goto out;
 
@@ -1987,7 +1987,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		return ret;
 
@@ -2195,7 +2195,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		return ret;
 
@@ -2549,7 +2549,7 @@ static long btrfs_ioctl_trans_start(struct file *file)
 	if (btrfs_root_readonly(root))
 		goto out;
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		goto out;
 

fs/ext2/ioctl.c

@@ -35,7 +35,7 @@ long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	case EXT2_IOC_SETFLAGS: {
 		unsigned int oldflags;
 
-		ret = mnt_want_write(filp->f_path.mnt);
+		ret = mnt_want_write_file(filp);
 		if (ret)
 			return ret;
 
@@ -91,7 +91,7 @@ long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	case EXT2_IOC_SETVERSION:
 		if (!inode_owner_or_capable(inode))
 			return -EPERM;
-		ret = mnt_want_write(filp->f_path.mnt);
+		ret = mnt_want_write_file(filp);
 		if (ret)
 			return ret;
 		if (get_user(inode->i_generation, (int __user *) arg)) {
@@ -121,7 +121,7 @@ long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (get_user(rsv_window_size, (int __user *)arg))
 			return -EFAULT;
 
-		ret = mnt_want_write(filp->f_path.mnt);
+		ret = mnt_want_write_file(filp);
 		if (ret)
 			return ret;
 

fs/ext3/ioctl.c

@@ -44,7 +44,7 @@ long ext3_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (get_user(flags, (int __user *) arg))
 			return -EFAULT;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 
@@ -126,7 +126,7 @@ long ext3_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!inode_owner_or_capable(inode))
 			return -EPERM;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 		if (get_user(generation, (int __user *) arg)) {
@@ -164,7 +164,7 @@ long ext3_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 			return -ENOTTY;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 
@@ -206,7 +206,7 @@ long ext3_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!capable(CAP_SYS_RESOURCE))
 			return -EPERM;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 
@@ -232,7 +232,7 @@ long ext3_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!capable(CAP_SYS_RESOURCE))
 			return -EPERM;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 

fs/ext4/ioctl.c

@@ -45,7 +45,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (get_user(flags, (int __user *) arg))
 			return -EFAULT;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 
@@ -150,7 +150,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!inode_owner_or_capable(inode))
 			return -EPERM;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 		if (get_user(generation, (int __user *) arg)) {
@@ -192,7 +192,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			return -EOPNOTSUPP;
 		}
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 
@@ -240,7 +240,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			return -EOPNOTSUPP;
 		}
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			goto mext_out;
 
@@ -277,7 +277,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			return -EOPNOTSUPP;
 		}
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 
@@ -301,7 +301,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!inode_owner_or_capable(inode))
 			return -EACCES;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 		/*
@@ -323,7 +323,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!inode_owner_or_capable(inode))
 			return -EACCES;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 		err = ext4_alloc_da_blocks(inode);

fs/fat/file.c

@@ -44,7 +44,7 @@ static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
 		goto out;
 
 	mutex_lock(&inode->i_mutex);
-	err = mnt_want_write(file->f_path.mnt);
+	err = mnt_want_write_file(file);
 	if (err)
 		goto out_unlock_inode;
 

fs/gfs2/file.c

@@ -223,7 +223,7 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
 	int error;
 	u32 new_flags, flags;
 
-	error = mnt_want_write(filp->f_path.mnt);
+	error = mnt_want_write_file(filp);
 	if (error)
 		return error;
 

fs/hfsplus/ioctl.c

@@ -43,7 +43,7 @@ static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
 	unsigned int flags;
 	int err = 0;
 
-	err = mnt_want_write(file->f_path.mnt);
+	err = mnt_want_write_file(file);
 	if (err)
 		goto out;
 

fs/jfs/ioctl.c

@@ -68,7 +68,7 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		unsigned int oldflags;
 		int err;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			return err;
 

fs/nfsd/nfs4recover.c

@@ -147,7 +147,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
 	status = -EEXIST;
 	if (dentry->d_inode)
 		goto out_put;
-	status = mnt_want_write(rec_file->f_path.mnt);
+	status = mnt_want_write_file(rec_file);
 	if (status)
 		goto out_put;
 	status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
@@ -268,7 +268,7 @@ nfsd4_remove_clid_dir(struct nfs4_client *clp)
 	if (!rec_file || !clp->cl_firststate)
 		return;
 
-	status = mnt_want_write(rec_file->f_path.mnt);
+	status = mnt_want_write_file(rec_file);
 	if (status)
 		goto out;
 	clp->cl_firststate = 0;
@@ -311,7 +311,7 @@ nfsd4_recdir_purge_old(void) {
 
 	if (!rec_file)
 		return;
-	status = mnt_want_write(rec_file->f_path.mnt);
+	status = mnt_want_write_file(rec_file);
 	if (status)
 		goto out;
 	status = nfsd4_list_rec_dir(purge_old);

fs/nilfs2/ioctl.c

@@ -27,7 +27,7 @@
 #include <linux/uaccess.h>	/* copy_from_user(), copy_to_user() */
 #include <linux/vmalloc.h>
 #include <linux/compat.h>	/* compat_ptr() */
-#include <linux/mount.h>	/* mnt_want_write(), mnt_drop_write() */
+#include <linux/mount.h>	/* mnt_want_write_file(), mnt_drop_write() */
 #include <linux/buffer_head.h>
 #include <linux/nilfs2_fs.h>
 #include "nilfs.h"
@@ -119,7 +119,7 @@ static int nilfs_ioctl_setflags(struct inode *inode, struct file *filp,
 	if (get_user(flags, (int __user *)argp))
 		return -EFAULT;
 
-	ret = mnt_want_write(filp->f_path.mnt);
+	ret = mnt_want_write_file(filp);
 	if (ret)
 		return ret;
 
@@ -174,7 +174,7 @@ static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	ret = mnt_want_write(filp->f_path.mnt);
+	ret = mnt_want_write_file(filp);
 	if (ret)
 		return ret;
 
@@ -210,7 +210,7 @@ nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	ret = mnt_want_write(filp->f_path.mnt);
+	ret = mnt_want_write_file(filp);
 	if (ret)
 		return ret;
 
@@ -591,7 +591,7 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	ret = mnt_want_write(filp->f_path.mnt);
+	ret = mnt_want_write_file(filp);
 	if (ret)
 		return ret;
 
@@ -710,7 +710,7 @@ static int nilfs_ioctl_resize(struct inode *inode, struct file *filp,
 	if (!capable(CAP_SYS_ADMIN))
 		goto out;
 
-	ret = mnt_want_write(filp->f_path.mnt);
+	ret = mnt_want_write_file(filp);
 	if (ret)
 		goto out;
 

fs/ocfs2/ioctl.c

@@ -906,7 +906,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (get_user(flags, (int __user *) arg))
 			return -EFAULT;
 
-		status = mnt_want_write(filp->f_path.mnt);
+		status = mnt_want_write_file(filp);
 		if (status)
 			return status;
 		status = ocfs2_set_inode_attr(inode, flags,

fs/ocfs2/move_extents.c

@@ -1059,7 +1059,7 @@ int ocfs2_ioctl_move_extents(struct file *filp, void __user *argp)
 	struct ocfs2_move_extents range;
 	struct ocfs2_move_extents_context *context = NULL;
 
-	status = mnt_want_write(filp->f_path.mnt);
+	status = mnt_want_write_file(filp);
 	if (status)
 		return status;
 

fs/reiserfs/ioctl.c

@@ -55,7 +55,7 @@ long reiserfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 				break;
 			}
 
-			err = mnt_want_write(filp->f_path.mnt);
+			err = mnt_want_write_file(filp);
 			if (err)
 				break;
 
@@ -107,7 +107,7 @@ long reiserfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			err = -EPERM;
 			break;
 		}
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			break;
 		if (get_user(inode->i_generation, (int __user *)arg)) {

fs/ubifs/ioctl.c

@@ -173,7 +173,7 @@ long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		 * Make sure the file-system is read-write and make sure it
 		 * will not become read-only while we are changing the flags.
 		 */
-		err = mnt_want_write(file->f_path.mnt);
+		err = mnt_want_write_file(file);
 		if (err)
 			return err;
 		dbg_gen("set flags: %#x, i_flags %#x", flags, inode->i_flags);

fs/xfs/xfs_ioctl.c

@@ -559,7 +559,7 @@ xfs_attrmulti_by_handle(
 					ops[i].am_flags);
 			break;
 		case ATTR_OP_SET:
-			ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
+			ops[i].am_error = mnt_want_write_file(parfilp);
 			if (ops[i].am_error)
 				break;
 			ops[i].am_error = xfs_attrmulti_attr_set(
@@ -569,7 +569,7 @@ xfs_attrmulti_by_handle(
 			mnt_drop_write(parfilp->f_path.mnt);
 			break;
 		case ATTR_OP_REMOVE:
-			ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
+			ops[i].am_error = mnt_want_write_file(parfilp);
 			if (ops[i].am_error)
 				break;
 			ops[i].am_error = xfs_attrmulti_attr_remove(

fs/xfs/xfs_ioctl32.c

@@ -454,7 +454,7 @@ xfs_compat_attrmulti_by_handle(
 					&ops[i].am_length, ops[i].am_flags);
 			break;
 		case ATTR_OP_SET:
-			ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
+			ops[i].am_error = mnt_want_write_file(parfilp);
 			if (ops[i].am_error)
 				break;
 			ops[i].am_error = xfs_attrmulti_attr_set(
@@ -464,7 +464,7 @@ xfs_compat_attrmulti_by_handle(
 			mnt_drop_write(parfilp->f_path.mnt);
 			break;
 		case ATTR_OP_REMOVE:
-			ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
+			ops[i].am_error = mnt_want_write_file(parfilp);
 			if (ops[i].am_error)
 				break;
 			ops[i].am_error = xfs_attrmulti_attr_remove(