udf: Fix possible corruption when close races with write
When we close a file, we remove preallocated blocks from it. But this
truncation was not protected by i_mutex and thus it could have raced with a
write through a different fd and cause crashes or even filesystem corruption.
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/file.c b/fs/udf/file.c
index 7464305..b80cbd7 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -193,9 +193,11 @@
static int udf_release_file(struct inode *inode, struct file *filp)
{
if (filp->f_mode & FMODE_WRITE) {
+ mutex_lock(&inode->i_mutex);
lock_kernel();
udf_discard_prealloc(inode);
unlock_kernel();
+ mutex_unlock(&inode->i_mutex);
}
return 0;
}
