JFS: fsync wrong behavior when I/O failure occurs

This is half of a patch that Qu Fuping submitted in April.  The first part
was applied to fs/mpage.c in 2.6.12-rc4.

jfs_fsync should return error, but it doesn't wait for the metadata page to
be uptodate, e.g.:
jfs_fsync->jfs_commit_inode->txCommit->diWrite->read_metapage->
__get_metapage->read_cache_page reads a page from disk. Because read is
async, when read_cache_page: err = filler(data, page), filler will not
return error, it just submits I/O request and returns. So, page is not
uptodate.  Checking only if(IS_ERROR(mp->page)) is not enough, we should
add "|| !PageUptodate(mp->page)"
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

fs/jfs/jfs_metapage.c

@@ -640,7 +640,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 	} else {
 		page = read_cache_page(mapping, page_index,
 			    (filler_t *)mapping->a_ops->readpage, NULL);
-		if (IS_ERR(page)) {
+		if (IS_ERR(page) || !PageUptodate(mp->page)) {
 			jfs_err("read_cache_page failed!");
 			return NULL;
 		}