staging: lustre: llog: reset llog bitmap

Once update request fails due to eviction or other failures,
all of update request in the sending list should return fail,
because after the failure, the update log in the following
request will have wrong llog bitmap.
Signed-off-by: Nwang di <di.wang@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7039
Reviewed-on: http://review.whamcloud.com/16969Reviewed-by: NAlex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: NJames Simmons <uja.ornl@yahoo.com>
Reviewed-by: NLai Siyao <lai.siyao@intel.com>
Reviewed-by: NOleg Drokin <oleg.drokin@intel.com>
Signed-off-by: NJames Simmons <jsimmons@infradead.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/llog.c

@@ -115,6 +115,7 @@ static int llog_read_header(const struct lu_env *env,
 	rc = lop->lop_read_header(env, handle);
 	if (rc == LLOG_EEMPTY) {
 		struct llog_log_hdr *llh = handle->lgh_hdr;
+		size_t len;
 
 		/* lrh_len should be initialized in llog_init_handle */
 		handle->lgh_last_idx = 0; /* header is record with index 0 */
@@ -128,6 +129,12 @@ static int llog_read_header(const struct lu_env *env,
 			memcpy(&llh->llh_tgtuuid, uuid,
 			       sizeof(llh->llh_tgtuuid));
 		llh->llh_bitmap_offset = offsetof(typeof(*llh), llh_bitmap);
+		/*
+		 * Since update llog header might also call this function,
+		 * let's reset the bitmap to 0 here
+		 */
+		len = llh->llh_hdr.lrh_len - llh->llh_bitmap_offset;
+		memset(LLOG_HDR_BITMAP(llh), 0, len - sizeof(llh->llh_tail));
 		ext2_set_bit(0, LLOG_HDR_BITMAP(llh));
 		LLOG_HDR_TAIL(llh)->lrt_len = llh->llh_hdr.lrh_len;
 		LLOG_HDR_TAIL(llh)->lrt_index = llh->llh_hdr.lrh_index;