fat: Push mnt_want_write() outside of i_mutex

When mnt_want_write() starts to handle freezing it will get a full lock
semantics requiring proper lock ordering. So push mnt_want_write() call
outside of i_mutex as in other places.

CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/fat/file.c b/fs/fat/file.c
index a71fe3715ee818b016fdc956e061399d734725d0..e007b8bd8e5ec1d93f29c65f877e083d3ec10b6e 100644 (file)
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -43,10 +43,10 @@ static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
        if (err)
                goto out;
 
-       mutex_lock(&inode->i_mutex);
        err = mnt_want_write_file(file);
        if (err)
-               goto out_unlock_inode;
+               goto out;
+       mutex_lock(&inode->i_mutex);
 
        /*
         * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
@@ -73,14 +73,14 @@ static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
        /* The root directory has no attributes */
        if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
                err = -EINVAL;
-               goto out_drop_write;
+               goto out_unlock_inode;
        }
 
        if (sbi->options.sys_immutable &&
            ((attr | oldattr) & ATTR_SYS) &&
            !capable(CAP_LINUX_IMMUTABLE)) {
                err = -EPERM;
-               goto out_drop_write;
+               goto out_unlock_inode;
        }
 
        /*
@@ -90,12 +90,12 @@ static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
         */
        err = security_inode_setattr(file->f_path.dentry, &ia);
        if (err)
-               goto out_drop_write;
+               goto out_unlock_inode;
 
        /* This MUST be done before doing anything irreversible... */
        err = fat_setattr(file->f_path.dentry, &ia);
        if (err)
-               goto out_drop_write;
+               goto out_unlock_inode;
 
        fsnotify_change(file->f_path.dentry, ia.ia_valid);
        if (sbi->options.sys_immutable) {
@@ -107,10 +107,9 @@ static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
 
        fat_save_attrs(inode, attr);
        mark_inode_dirty(inode);
-out_drop_write:
-       mnt_drop_write_file(file);
 out_unlock_inode:
        mutex_unlock(&inode->i_mutex);
+       mnt_drop_write_file(file);
 out:
        return err;
 }