Merge branch 'ro-bind.b6' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'ro-bind.b6' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (24 commits)
  [PATCH] r/o bind mounts: debugging for missed calls
  [PATCH] r/o bind mounts: honor mount writer counts at remount
  [PATCH] r/o bind mounts: track numbers of writers to mounts
  [PATCH] r/o bind mounts: check mnt instead of superblock directly
  [PATCH] r/o bind mounts: elevate count for xfs timestamp updates
  [PATCH] r/o bind mounts: make access() use new r/o helper
  [PATCH] r/o bind mounts: write counts for truncate()
  [PATCH] r/o bind mounts: elevate write count for chmod/chown callers
  [PATCH] r/o bind mounts: elevate write count for open()s
  [PATCH] r/o bind mounts: elevate write count for ioctls()
  [PATCH] r/o bind mounts: write count for file_update_time()
  [PATCH] r/o bind mounts: elevate write count for do_utimes()
  [PATCH] r/o bind mounts: write counts for touch_atime()
  [PATCH] r/o bind mounts: elevate write count for ncp_ioctl()
  [PATCH] r/o bind mounts: elevate write count for xattr_permission() callers
  [PATCH] r/o bind mounts: get write access for vfs_rename() callers
  [PATCH] r/o bind mounts: write counts for link/symlink
  [PATCH] r/o bind mounts: get callers of vfs_mknod/create/mkdir()
  [PATCH] r/o bind mounts: elevate write count for rmdir and unlink.
  [PATCH] r/o bind mounts: drop write during emergency remount
  ...

1 files changed, 7 insertions, 5 deletions

diff --git a/fs/fat/file.c b/fs/fat/file.c
index c614175876e..2a3bed96704 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -8,6 +8,7 @@
 
 #include <linux/capability.h>
 #include <linux/module.h>
+#include <linux/mount.h>
 #include <linux/time.h>
 #include <linux/msdos_fs.h>
 #include <linux/smp_lock.h>
@@ -46,10 +47,9 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
 
 		mutex_lock(&inode->i_mutex);
 
-		if (IS_RDONLY(inode)) {
-			err = -EROFS;
-			goto up;
-		}
+		err = mnt_want_write(filp->f_path.mnt);
+		if (err)
+			goto up_no_drop_write;
 
 		/*
 		 * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
@@ -105,7 +105,9 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
 
 		MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
 		mark_inode_dirty(inode);
-	up:
+up:
+		mnt_drop_write(filp->f_path.mnt);
+up_no_drop_write:
 		mutex_unlock(&inode->i_mutex);
 		return err;
 	}