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ABD: Be more assertive in iterators
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Once we verified the ABDs and asserted the sizes we should never
see premature ABDs ends.  Assert that and remove extra branches
from production builds.

Reviewed-by: Brian Atkinson <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by:	Alexander Motin <[email protected]>
Sponsored by:	iXsystems, Inc.
Closes #15428
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@amotin
amotin authored Oct 24, 2023
1 parent 07345ac commit e007908
Showing 1 changed file with 26 additions and 78 deletions.
104 changes: 26 additions & 78 deletions module/zfs/abd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -802,13 +802,10 @@ abd_iterate_func(abd_t *abd, size_t off, size_t size,
abd_verify(abd);
ASSERT3U(off + size, <=, abd->abd_size);

boolean_t gang = abd_is_gang(abd);
abd_t *c_abd = abd_init_abd_iter(abd, &aiter, off);

while (size > 0) {
/* If we are at the end of the gang ABD we are done */
if (gang && !c_abd)
break;
IMPLY(abd_is_gang(abd), c_abd != NULL);

abd_iter_map(&aiter);

Expand Down Expand Up @@ -930,7 +927,6 @@ abd_iterate_func2(abd_t *dabd, abd_t *sabd, size_t doff, size_t soff,
{
int ret = 0;
struct abd_iter daiter, saiter;
boolean_t dabd_is_gang_abd, sabd_is_gang_abd;
abd_t *c_dabd, *c_sabd;

if (size == 0)
Expand All @@ -942,16 +938,12 @@ abd_iterate_func2(abd_t *dabd, abd_t *sabd, size_t doff, size_t soff,
ASSERT3U(doff + size, <=, dabd->abd_size);
ASSERT3U(soff + size, <=, sabd->abd_size);

dabd_is_gang_abd = abd_is_gang(dabd);
sabd_is_gang_abd = abd_is_gang(sabd);
c_dabd = abd_init_abd_iter(dabd, &daiter, doff);
c_sabd = abd_init_abd_iter(sabd, &saiter, soff);

while (size > 0) {
/* if we are at the end of the gang ABD we are done */
if ((dabd_is_gang_abd && !c_dabd) ||
(sabd_is_gang_abd && !c_sabd))
break;
IMPLY(abd_is_gang(dabd), c_dabd != NULL);
IMPLY(abd_is_gang(sabd), c_sabd != NULL);

abd_iter_map(&daiter);
abd_iter_map(&saiter);
Expand Down Expand Up @@ -1032,66 +1024,40 @@ abd_raidz_gen_iterate(abd_t **cabds, abd_t *dabd,
int i;
ssize_t len, dlen;
struct abd_iter caiters[3];
struct abd_iter daiter = {0};
struct abd_iter daiter;
void *caddrs[3];
unsigned long flags __maybe_unused = 0;
abd_t *c_cabds[3];
abd_t *c_dabd = NULL;
boolean_t cabds_is_gang_abd[3];
boolean_t dabd_is_gang_abd = B_FALSE;

ASSERT3U(parity, <=, 3);

for (i = 0; i < parity; i++) {
cabds_is_gang_abd[i] = abd_is_gang(cabds[i]);
abd_verify(cabds[i]);
ASSERT3U(csize, <=, cabds[i]->abd_size);
c_cabds[i] = abd_init_abd_iter(cabds[i], &caiters[i], 0);
}

if (dabd) {
dabd_is_gang_abd = abd_is_gang(dabd);
ASSERT3S(dsize, >=, 0);
if (dsize > 0) {
ASSERT(dabd);
abd_verify(dabd);
ASSERT3U(dsize, <=, dabd->abd_size);
c_dabd = abd_init_abd_iter(dabd, &daiter, 0);
}

ASSERT3S(dsize, >=, 0);

abd_enter_critical(flags);
while (csize > 0) {
/* if we are at the end of the gang ABD we are done */
if (dabd_is_gang_abd && !c_dabd)
break;

len = csize;
for (i = 0; i < parity; i++) {
/*
* If we are at the end of the gang ABD we are
* done.
*/
if (cabds_is_gang_abd[i] && !c_cabds[i])
break;
IMPLY(abd_is_gang(cabds[i]), c_cabds[i] != NULL);
abd_iter_map(&caiters[i]);
caddrs[i] = caiters[i].iter_mapaddr;
len = MIN(caiters[i].iter_mapsize, len);
}

len = csize;

if (dabd && dsize > 0)
if (dsize > 0) {
IMPLY(abd_is_gang(dabd), c_dabd != NULL);
abd_iter_map(&daiter);

switch (parity) {
case 3:
len = MIN(caiters[2].iter_mapsize, len);
zfs_fallthrough;
case 2:
len = MIN(caiters[1].iter_mapsize, len);
zfs_fallthrough;
case 1:
len = MIN(caiters[0].iter_mapsize, len);
}

/* must be progressive */
ASSERT3S(len, >, 0);

if (dabd && dsize > 0) {
/* this needs precise iter.length */
len = MIN(daiter.iter_mapsize, len);
dlen = len;
} else
Expand All @@ -1114,7 +1080,7 @@ abd_raidz_gen_iterate(abd_t **cabds, abd_t *dabd,
&caiters[i], len);
}

if (dabd && dsize > 0) {
if (dsize > 0) {
abd_iter_unmap(&daiter);
c_dabd =
abd_advance_abd_iter(dabd, c_dabd, &daiter,
Expand Down Expand Up @@ -1153,16 +1119,16 @@ abd_raidz_rec_iterate(abd_t **cabds, abd_t **tabds,
struct abd_iter xiters[3];
void *caddrs[3], *xaddrs[3];
unsigned long flags __maybe_unused = 0;
boolean_t cabds_is_gang_abd[3];
boolean_t tabds_is_gang_abd[3];
abd_t *c_cabds[3];
abd_t *c_tabds[3];

ASSERT3U(parity, <=, 3);

for (i = 0; i < parity; i++) {
cabds_is_gang_abd[i] = abd_is_gang(cabds[i]);
tabds_is_gang_abd[i] = abd_is_gang(tabds[i]);
abd_verify(cabds[i]);
abd_verify(tabds[i]);
ASSERT3U(tsize, <=, cabds[i]->abd_size);
ASSERT3U(tsize, <=, tabds[i]->abd_size);
c_cabds[i] =
abd_init_abd_iter(cabds[i], &citers[i], 0);
c_tabds[i] =
Expand All @@ -1171,36 +1137,18 @@ abd_raidz_rec_iterate(abd_t **cabds, abd_t **tabds,

abd_enter_critical(flags);
while (tsize > 0) {

len = tsize;
for (i = 0; i < parity; i++) {
/*
* If we are at the end of the gang ABD we
* are done.
*/
if (cabds_is_gang_abd[i] && !c_cabds[i])
break;
if (tabds_is_gang_abd[i] && !c_tabds[i])
break;
IMPLY(abd_is_gang(cabds[i]), c_cabds[i] != NULL);
IMPLY(abd_is_gang(tabds[i]), c_tabds[i] != NULL);
abd_iter_map(&citers[i]);
abd_iter_map(&xiters[i]);
caddrs[i] = citers[i].iter_mapaddr;
xaddrs[i] = xiters[i].iter_mapaddr;
len = MIN(citers[i].iter_mapsize, len);
len = MIN(xiters[i].iter_mapsize, len);
}

len = tsize;
switch (parity) {
case 3:
len = MIN(xiters[2].iter_mapsize, len);
len = MIN(citers[2].iter_mapsize, len);
zfs_fallthrough;
case 2:
len = MIN(xiters[1].iter_mapsize, len);
len = MIN(citers[1].iter_mapsize, len);
zfs_fallthrough;
case 1:
len = MIN(xiters[0].iter_mapsize, len);
len = MIN(citers[0].iter_mapsize, len);
}
/* must be progressive */
ASSERT3S(len, >, 0);
/*
Expand Down

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