Commit f6940fe9 authored Feb 20, 2012 by Jan Kara Committed by Al Viro Mar 10, 2012

udf: Fix deadlock in udf_release_file()



udf_release_file() can be called from munmap() path with mmap_sem held.  Thus
we cannot take i_mutex there because that ranks above mmap_sem. Luckily,
i_mutex is not needed in udf_release_file() anymore since protection by
i_data_sem is enough to protect from races with write and truncate.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent 978d6d8c

fs/udf/file.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -201,12 +201,10 @@ long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
		static int udf_release_file(struct inode inode, struct file filp)
		{
		if (filp->f_mode & FMODE_WRITE) {
		mutex_lock(&inode->i_mutex);
		down_write(&UDF_I(inode)->i_data_sem);
		udf_discard_prealloc(inode);
		udf_truncate_tail_extent(inode);
		up_write(&UDF_I(inode)->i_data_sem);
		mutex_unlock(&inode->i_mutex);
		}
		return 0;
		}