Commit 22e7478d authored May 21, 2014 by Jeff Mahoney Committed by Jan Kara May 21, 2014

reiserfs: call truncate_setsize under tailpack mutex



Prior to commit 0e4f6a79 (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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>

parent 770901cc

fs/reiserfs/inode.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -3422,8 +3422,14 @@ 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);
		}
		}

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