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Fix object reclaim when using large dnodes
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Currently, when the receive_object() code wants to reclaim an
object, it always assumes that the dnode is the legacy 512 bytes,
even when the incoming bonus buffer exceeds this length. This
causes a buffer overflow if --enable-debug is not provided and
triggers an ASSERT if it is. This patch resolves this issue and
adds an ASSERT to ensure this can't happen again.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes openzfs#7097
Closes openzfs#7433
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Tom Caputi authored and dweeezil committed Aug 28, 2018
1 parent 5324c79 commit d1866c7
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Showing 4 changed files with 22 additions and 9 deletions.
2 changes: 1 addition & 1 deletion module/zfs/dmu_object.c
Original file line number Diff line number Diff line change
Expand Up @@ -249,7 +249,7 @@ dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
return (dmu_object_reclaim_dnsize(os, object, ot, blocksize, bonustype,
bonuslen, 0, tx));
bonuslen, DNODE_MIN_SIZE, tx));
}

int
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5 changes: 3 additions & 2 deletions module/zfs/dmu_send.c
Original file line number Diff line number Diff line change
Expand Up @@ -2244,9 +2244,10 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
drro->drr_bonustype != doi.doi_bonus_type ||
drro->drr_bonuslen != doi.doi_bonus_size) {
/* currently allocated, but with different properties */
err = dmu_object_reclaim(rwa->os, drro->drr_object,
err = dmu_object_reclaim_dnsize(rwa->os, drro->drr_object,
drro->drr_type, drro->drr_blksz,
drro->drr_bonustype, drro->drr_bonuslen, tx);
drro->drr_bonustype, drro->drr_bonuslen,
drro->drr_dn_slots << DNODE_SHIFT, tx);
}
if (err != 0) {
dmu_tx_commit(tx);
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3 changes: 1 addition & 2 deletions module/zfs/dnode.c
Original file line number Diff line number Diff line change
Expand Up @@ -662,8 +662,7 @@ dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
ASSERT(DMU_OT_IS_VALID(bonustype));
ASSERT3U(bonuslen, <=,
DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(dn->dn_objset))));

dn_slots = dn_slots > 0 ? dn_slots : DNODE_MIN_SLOTS;
ASSERT3U(bonuslen, <=, DN_BONUS_SIZE(dn_slots << DNODE_SHIFT));

dnode_free_interior_slots(dn);
DNODE_STAT_BUMP(dnode_reallocate);
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21 changes: 17 additions & 4 deletions tests/zfs-tests/tests/functional/rsend/send_realloc_dnode_size.ksh
100644 → 100755
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@

#
# Copyright (c) 2017 by Lawrence Livermore National Security, LLC.
# Copyright (c) 2018 Datto Inc.
#

. $STF_SUITE/include/libtest.shlib
Expand All @@ -31,8 +32,10 @@
# 3. Remove objects, set dnodesize=2k, and remount dataset so new objects
# overlap with recently recycled and formerly "normal" dnode slots get
# assigned to new objects
# 4. Generate initial and incremental streams
# 5. Verify initial and incremental streams can be received
# 4. Create an empty file and add xattrs to it to exercise reclaiming a
# dnode that requires more than 1 slot for its bonus buffer (Zol #7433)
# 5. Generate initial and incremental streams
# 6. Verify initial and incremental streams can be received
#

verify_runnable "both"
Expand All @@ -44,6 +47,7 @@ function cleanup
rm -f $BACKDIR/fs-dn-legacy
rm -f $BACKDIR/fs-dn-1k
rm -f $BACKDIR/fs-dn-2k
rm -f $BACKDIR/fs-attr

if datasetexists $POOL/fs ; then
log_must zfs destroy -rR $POOL/fs
Expand Down Expand Up @@ -82,17 +86,26 @@ log_must zfs unmount $POOL/fs
log_must zfs set dnodesize=2k $POOL/fs
log_must zfs mount $POOL/fs

log_must touch /$POOL/fs/attrs
mk_files 200 262144 0 $POOL/fs
log_must zfs snapshot $POOL/fs@c

# 4. Generate initial and incremental streams
# 4. Create an empty file and add xattrs to it to exercise reclaiming a
# dnode that requires more than 1 slot for its bonus buffer (Zol #7433)
log_must zfs set compression=on xattr=sa $POOL/fs
log_must eval "python -c 'print \"a\" * 512' | attr -s bigval /$POOL/fs/attrs"
log_must zfs snapshot $POOL/fs@d

# 5. Generate initial and incremental streams
log_must eval "zfs send $POOL/fs@a > $BACKDIR/fs-dn-1k"
log_must eval "zfs send -i $POOL/fs@a $POOL/fs@b > $BACKDIR/fs-dn-legacy"
log_must eval "zfs send -i $POOL/fs@b $POOL/fs@c > $BACKDIR/fs-dn-2k"
log_must eval "zfs send -i $POOL/fs@c $POOL/fs@d > $BACKDIR/fs-attr"

# 5. Verify initial and incremental streams can be received
# 6. Verify initial and incremental streams can be received
log_must eval "zfs recv $POOL/newfs < $BACKDIR/fs-dn-1k"
log_must eval "zfs recv $POOL/newfs < $BACKDIR/fs-dn-legacy"
log_must eval "zfs recv $POOL/newfs < $BACKDIR/fs-dn-2k"
log_must eval "zfs recv $POOL/newfs < $BACKDIR/fs-attr"

log_pass "Verify incremental receive handles objects with changed dnode size"

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