reiserfs: call truncate_setsize under tailpack mutex

commit 22e7478ddbcb670e33fab72d0bbe7c394c3a2c84 upstream.

Prior to commit 0e4f6a791b1e (Fix reiserfs_file_release()), reiserfs
truncates serialized on i_mutex. They mostly still do, with the exception
of reiserfs_file_release. That blocks out other writers via the tailpack
mutex and the inode openers counter adjusted in reiserfs_file_open.

However, NFS will call reiserfs_setattr without having called ->open, so
we end up with a race when nfs is calling ->setattr while another
process is releasing the file. Ultimately, it triggers the
BUG_ON(inode->i_size != new_file_size) check in maybe_indirect_to_direct.

The solution is to pull the lock into reiserfs_setattr to encompass the
truncate_setsize call as well.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index a4c6d99..fcb07e5 100644 (file)
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -3211,8 +3211,14 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
            attr->ia_size != i_size_read(inode)) {
                error = inode_newsize_ok(inode, attr->ia_size);
                if (!error) {
+                       /*
+                        * Could race against reiserfs_file_release
+                        * if called from NFS, so take tailpack mutex.
+                        */
+                       mutex_lock(&REISERFS_I(inode)->tailpack);
                        truncate_setsize(inode, attr->ia_size);
-                       reiserfs_vfs_truncate_file(inode);
+                       reiserfs_truncate_file(inode, 1);
+                       mutex_unlock(&REISERFS_I(inode)->tailpack);
                }
        }