Commit b28813a6 authored by Sage Weil's avatar Sage Weil
Browse files

ceph: gracefully avoid empty crush buckets 



This avoids a divide by zero when the input and/or map are
malformed.

Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent b195befd

fs/ceph/crush/mapper.c

+7 −2
Original line number Diff line number Diff line
@@ -299,7 +299,7 @@ static int crush_choose(struct crush_map *map, 
	struct crush_bucket *in = bucket;

	int r;

	int i;

	int item;

	int item = 0;

	int itemtype;

	int collide, reject;

	const int orig_tries = 5; /* attempts before we fall back to search */
@@ -316,6 +316,7 @@ static int crush_choose(struct crush_map *map, 
			/* choose through intervening buckets */

			flocal = 0;

			do {

				collide = 0;

				retry_bucket = 0;

				r = rep;

				if (in->alg == CRUSH_BUCKET_UNIFORM) {
@@ -340,6 +341,10 @@ static int crush_choose(struct crush_map *map, 
				}



				/* bucket choose */

				if (in->size == 0) {

					reject = 1;

					goto reject;

				}

				if (flocal >= (in->size>>1) &&

				    flocal > orig_tries)

					item = bucket_perm_choose(in, x, r);
@@ -363,7 +368,6 @@ static int crush_choose(struct crush_map *map, 
				}



				/* collision? */

				collide = 0;

				for (i = 0; i < outpos; i++) {

					if (out[i] == item) {

						collide = 1;
@@ -388,6 +392,7 @@ static int crush_choose(struct crush_map *map, 
						reject = 0;

				}



reject:

				if (reject || collide) {

					ftotal++;

					flocal++;