[PATCH] r/o bind mounts: elevate write count for ioctls()

[linux-2.6-omap-h63xx.git] / fs / fat / file.c

diff --git a/fs/fat/file.c b/fs/fat/file.c
index c614175876e09316ea0a36566dc072fe6819169c..2a3bed96704148c1377537677c4c7d9edd9372a3 100644 (file)
--- 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;
        }