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Fix stack ddt_zap_lookup()

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Stack usage for ddt_zap_lookup() reduced from 368 bytes to 120
bytes.  This large stack allocation significantly contributed to
the likelyhood of a stack overflow when scrubbing/resilvering
dedup pools.
This commit is contained in:
Brian Behlendorf 2011-05-25 14:13:18 -07:00
parent c7f8f831a4
commit 5b8c7bbcea
1 changed files with 8 additions and 4 deletions
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12
module/zfs/ddt_zap.c
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@ -58,14 +58,16 @@ ddt_zap_destroy(objset_t *os, uint64_t object, dmu_tx_t *tx)
static int
ddt_zap_lookup(objset_t *os, uint64_t object, ddt_entry_t *dde)
{
uchar_t cbuf[sizeof (dde->dde_phys) + 1];
uchar_t *cbuf;
uint64_t one, csize;
int error;
cbuf = kmem_alloc(sizeof (dde->dde_phys) + 1, KM_SLEEP);
error = zap_length_uint64(os, object, (uint64_t *)&dde->dde_key,
DDT_KEY_WORDS, &one, &csize);
if (error)
return (error);
goto out;
ASSERT(one == 1);
ASSERT(csize <= sizeof (cbuf));
@ -73,11 +75,13 @@ ddt_zap_lookup(objset_t *os, uint64_t object, ddt_entry_t *dde)
error = zap_lookup_uint64(os, object, (uint64_t *)&dde->dde_key,
DDT_KEY_WORDS, 1, csize, cbuf);
if (error)
return (error);
goto out;
ddt_decompress(cbuf, dde->dde_phys, csize, sizeof (dde->dde_phys));
out:
kmem_free(cbuf, sizeof (dde->dde_phys) + 1);
return (0);
return (error);
}
static void