Commit 7e768532 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
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dm snapshot: properly fix a crash when an origin has no snapshots

If an origin target has no snapshots, o->split_boundary is set to 0.
This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split().

Fix this by initializing chunk_size, and in turn split_boundary, to
rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits
into "unsigned" type.

Signed-off-by: default avatarMikulas Patocka <>
Signed-off-by: default avatarMike Snitzer <>
parent f16dba5d
......@@ -855,7 +855,7 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new)
static uint32_t __minimum_chunk_size(struct origin *o)
struct dm_snapshot *snap;
unsigned chunk_size = 0;
unsigned chunk_size = rounddown_pow_of_two(UINT_MAX);
if (o)
list_for_each_entry(snap, &o->snapshots, list)
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