From: Dave Hansen <hansendc@us.ibm.com>

Some ioctl()s can cause writes to the filesystem.  Take
these, and make them use mnt_want/drop_write() instead.

We need to pass the filp one layer deeper in XFS, but
somebody _just_ pulled it out in February because nobody
was using it, so I don't feel guilty for adding it back.

Signed-off-by: Dave Hansen <hansendc@us.ibm.com>
---

---
 fs/ext2/ioctl.c              |   67 ++++++++++++++++++---------
 fs/ext3/ioctl.c              |  100 +++++++++++++++++++++++++++-------------
 fs/ext4/ioctl.c              |  105 +++++++++++++++++++++++++++----------------
 fs/fat/file.c                |    9 ++-
 fs/hfsplus/ioctl.c           |   39 +++++++++------
 fs/jfs/ioctl.c               |   33 ++++++++-----
 fs/ocfs2/ioctl.c             |   11 ++--
 fs/reiserfs/ioctl.c          |   52 +++++++++++++--------
 fs/xfs/linux-2.6/xfs_ioctl.c |   12 +++-
 fs/xfs/linux-2.6/xfs_iops.c  |    7 --
 fs/xfs/linux-2.6/xfs_lrw.c   |    8 ++-
 11 files changed, 281 insertions(+), 162 deletions(-)

Index: 2.6.22-rc4-mm2-robindmount/fs/ext2/ioctl.c
===================================================================
--- 2.6.22-rc4-mm2-robindmount.orig/fs/ext2/ioctl.c
+++ 2.6.22-rc4-mm2-robindmount/fs/ext2/ioctl.c
@@ -12,6 +12,7 @@
 #include <linux/time.h>
 #include <linux/sched.h>
 #include <linux/compat.h>
+#include <linux/mount.h>
 #include <linux/smp_lock.h>
 #include <asm/current.h>
 #include <asm/uaccess.h>
@@ -23,6 +24,7 @@ int ext2_ioctl (struct inode * inode, st
 	struct ext2_inode_info *ei = EXT2_I(inode);
 	unsigned int flags;
 	unsigned short rsv_window_size;
+	int ret;
 
 	ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
 
@@ -34,14 +36,19 @@ int ext2_ioctl (struct inode * inode, st
 	case EXT2_IOC_SETFLAGS: {
 		unsigned int oldflags;
 
-		if (IS_RDONLY(inode))
-			return -EROFS;
-
-		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
-			return -EACCES;
+		ret = mnt_want_write(filp->f_vfsmnt);
+		if (ret)
+			return ret;
+
+		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) {
+			ret = -EACCES;
+			goto setflags_out;
+		}
 
-		if (get_user(flags, (int __user *) arg))
-			return -EFAULT;
+		if (get_user(flags, (int __user *) arg)) {
+			ret = -EFAULT;
+			goto setflags_out;
+		}
 
 		if (!S_ISDIR(inode->i_mode))
 			flags &= ~EXT2_DIRSYNC_FL;
@@ -58,7 +65,8 @@ int ext2_ioctl (struct inode * inode, st
 		if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
 			if (!capable(CAP_LINUX_IMMUTABLE)) {
 				mutex_unlock(&inode->i_mutex);
-				return -EPERM;
+				ret = -EPERM;
+				goto setflags_out;
 			}
 		}
 
@@ -70,19 +78,25 @@ int ext2_ioctl (struct inode * inode, st
 		ext2_set_inode_flags(inode);
 		inode->i_ctime = CURRENT_TIME_SEC;
 		mark_inode_dirty(inode);
-		return 0;
+	setflags_out:
+		mnt_drop_write(filp->f_vfsmnt);
+		return ret;
 	}
 	case EXT2_IOC_GETVERSION:
 		return put_user(inode->i_generation, (int __user *) arg);
 	case EXT2_IOC_SETVERSION:
 		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
 			return -EPERM;
-		if (IS_RDONLY(inode))
-			return -EROFS;
-		if (get_user(inode->i_generation, (int __user *) arg))
-			return -EFAULT;	
-		inode->i_ctime = CURRENT_TIME_SEC;
-		mark_inode_dirty(inode);
+		ret = mnt_want_write(filp->f_vfsmnt);
+		if (ret)
+			return ret;
+		if (get_user(inode->i_generation, (int __user *) arg)) {
+			ret = -EFAULT;
+		} else {
+			inode->i_ctime = CURRENT_TIME_SEC;
+			mark_inode_dirty(inode);
+		}
+		mnt_drop_write(filp->f_vfsmnt);
 		return 0;
 	case EXT2_IOC_GETRSVSZ:
 		if (test_opt(inode->i_sb, RESERVATION)
@@ -97,14 +111,19 @@ int ext2_ioctl (struct inode * inode, st
 		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 			return -ENOTTY;
 
-		if (IS_RDONLY(inode))
-			return -EROFS;
-
-		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
-			return -EACCES;
+		ret = mnt_want_write(filp->f_vfsmnt);
+		if (ret)
+			return ret;
+
+		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) {
+			ret = -EACCES;
+			goto setrsvsz_out;
+		}
 
-		if (get_user(rsv_window_size, (int __user *)arg))
-			return -EFAULT;
+		if (get_user(rsv_window_size, (int __user *)arg)) {
+			ret = -EFAULT;
+			goto setrsvsz_out;
+		}
 
 		if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
 			rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
@@ -126,7 +145,9 @@ int ext2_ioctl (struct inode * inode, st
 			rsv->rsv_goal_size = rsv_window_size;
 		}
 		mutex_unlock(&ei->truncate_mutex);
-		return 0;
+	setrsvsz_out:
+		mnt_drop_write(filp->f_vfsmnt);
+		return ret;
 	}
 	default:
 		return -ENOTTY;
Index: 2.6.22-rc4-mm2-robindmount/fs/ext3/ioctl.c
===================================================================
--- 2.6.22-rc4-mm2-robindmount.orig/fs/ext3/ioctl.c
+++ 2.6.22-rc4-mm2-robindmount/fs/ext3/ioctl.c
@@ -12,6 +12,7 @@
 #include <linux/capability.h>
 #include <linux/ext3_fs.h>
 #include <linux/ext3_jbd.h>
+#include <linux/mount.h>
 #include <linux/time.h>
 #include <linux/compat.h>
 #include <linux/smp_lock.h>
@@ -38,14 +39,19 @@ int ext3_ioctl (struct inode * inode, st
 		unsigned int oldflags;
 		unsigned int jflag;
 
-		if (IS_RDONLY(inode))
-			return -EROFS;
+		err = mnt_want_write(filp->f_vfsmnt);
+		if (err)
+			return err;
 
-		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
-			return -EACCES;
+		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) {
+			err = -EACCES;
+			goto flags_out;
+		}
 
-		if (get_user(flags, (int __user *) arg))
-			return -EFAULT;
+		if (get_user(flags, (int __user *) arg)) {
+			err = -EFAULT;
+			goto flags_out;
+		}
 
 		if (!S_ISDIR(inode->i_mode))
 			flags &= ~EXT3_DIRSYNC_FL;
@@ -65,7 +71,8 @@ int ext3_ioctl (struct inode * inode, st
 		if ((flags ^ oldflags) & (EXT3_APPEND_FL | EXT3_IMMUTABLE_FL)) {
 			if (!capable(CAP_LINUX_IMMUTABLE)) {
 				mutex_unlock(&inode->i_mutex);
-				return -EPERM;
+				err = -EPERM;
+				goto flags_out;
 			}
 		}
 
@@ -76,7 +83,8 @@ int ext3_ioctl (struct inode * inode, st
 		if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL)) {
 			if (!capable(CAP_SYS_RESOURCE)) {
 				mutex_unlock(&inode->i_mutex);
-				return -EPERM;
+				err = -EPERM;
+				goto flags_out;
 			}
 		}
 
@@ -84,7 +92,8 @@ int ext3_ioctl (struct inode * inode, st
 		handle = ext3_journal_start(inode, 1);
 		if (IS_ERR(handle)) {
 			mutex_unlock(&inode->i_mutex);
-			return PTR_ERR(handle);
+			err = PTR_ERR(handle);
+			goto flags_out;
 		}
 		if (IS_SYNC(inode))
 			handle->h_sync = 1;
@@ -110,6 +119,8 @@ flags_err:
 		if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL))
 			err = ext3_change_inode_journal_flag(inode, jflag);
 		mutex_unlock(&inode->i_mutex);
+	flags_out:
+		mnt_drop_write(filp->f_vfsmnt);
 		return err;
 	}
 	case EXT3_IOC_GETVERSION:
@@ -124,14 +135,18 @@ flags_err:
 
 		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
 			return -EPERM;
-		if (IS_RDONLY(inode))
-			return -EROFS;
-		if (get_user(generation, (int __user *) arg))
-			return -EFAULT;
-
+		err = mnt_want_write(filp->f_vfsmnt);
+		if (err)
+			return err;
+		if (get_user(generation, (int __user *) arg)) {
+			err = -EFAULT;
+			goto setversion_out;
+		}
 		handle = ext3_journal_start(inode, 1);
-		if (IS_ERR(handle))
-			return PTR_ERR(handle);
+		if (IS_ERR(handle)) {
+			err = PTR_ERR(handle);
+			goto setversion_out;
+		}
 		err = ext3_reserve_inode_write(handle, inode, &iloc);
 		if (err == 0) {
 			inode->i_ctime = CURRENT_TIME_SEC;
@@ -139,6 +154,8 @@ flags_err:
 			err = ext3_mark_iloc_dirty(handle, inode, &iloc);
 		}
 		ext3_journal_stop(handle);
+	setversion_out:
+		mnt_drop_write(filp->f_vfsmnt);
 		return err;
 	}
 #ifdef CONFIG_JBD_DEBUG
@@ -174,18 +191,24 @@ flags_err:
 		}
 		return -ENOTTY;
 	case EXT3_IOC_SETRSVSZ: {
+		int err;
 
 		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 			return -ENOTTY;
 
-		if (IS_RDONLY(inode))
-			return -EROFS;
+		err = mnt_want_write(filp->f_vfsmnt);
+		if (err)
+			return err;
 
-		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
-			return -EACCES;
+		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) {
+			err = -EACCES;
+			goto setrsvsz_out;
+		}
 
-		if (get_user(rsv_window_size, (int __user *)arg))
-			return -EFAULT;
+		if (get_user(rsv_window_size, (int __user *)arg)) {
+			err = -EFAULT;
+			goto setrsvsz_out;
+		}
 
 		if (rsv_window_size > EXT3_MAX_RESERVE_BLOCKS)
 			rsv_window_size = EXT3_MAX_RESERVE_BLOCKS;
@@ -203,7 +226,9 @@ flags_err:
 			rsv->rsv_goal_size = rsv_window_size;
 		}
 		mutex_unlock(&ei->truncate_mutex);
-		return 0;
+	setrsvsz_out:
+		mnt_drop_write(filp->f_vfsmnt);
+		return err;
 	}
 	case EXT3_IOC_GROUP_EXTEND: {
 		ext3_fsblk_t n_blocks_count;
@@ -213,17 +238,20 @@ flags_err:
 		if (!capable(CAP_SYS_RESOURCE))
 			return -EPERM;
 
-		if (IS_RDONLY(inode))
-			return -EROFS;
-
-		if (get_user(n_blocks_count, (__u32 __user *)arg))
-			return -EFAULT;
+		err = mnt_want_write(filp->f_vfsmnt);
+		if (err)
+			return err;
 
+		if (get_user(n_blocks_count, (__u32 __user *)arg)) {
+			err = -EFAULT;
+			goto group_extend_out;
+		}
 		err = ext3_group_extend(sb, EXT3_SB(sb)->s_es, n_blocks_count);
 		journal_lock_updates(EXT3_SB(sb)->s_journal);
 		journal_flush(EXT3_SB(sb)->s_journal);
 		journal_unlock_updates(EXT3_SB(sb)->s_journal);
-
+	group_extend_out:
+		mnt_drop_write(filp->f_vfsmnt);
 		return err;
 	}
 	case EXT3_IOC_GROUP_ADD: {
@@ -234,18 +262,22 @@ flags_err:
 		if (!capable(CAP_SYS_RESOURCE))
 			return -EPERM;
 
-		if (IS_RDONLY(inode))
-			return -EROFS;
+		err =