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4047 panic from dbuf_free_range() from dmu_free_object() while doing zfs receive
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>

*** 567,669 **** /* * Get the next "chunk" of file data to free. We traverse the file from * the end so that the file gets shorter over time (if we crashes in the * middle, this will leave us in a better state). We find allocated file * data by simply searching the allocated level 1 indirects. */ static int ! get_next_chunk(dnode_t *dn, uint64_t *start, uint64_t limit) { ! uint64_t len = *start - limit; ! uint64_t blkcnt = 0; ! uint64_t maxblks = DMU_MAX_ACCESS / (1ULL << (dn->dn_indblkshift + 1)); uint64_t iblkrange = dn->dn_datablksz * EPB(dn->dn_indblkshift, SPA_BLKPTRSHIFT); ! ASSERT(limit <= *start); ! if (len <= iblkrange * maxblks) { ! *start = limit; return (0); } ASSERT(ISP2(iblkrange)); ! while (*start > limit && blkcnt < maxblks) { int err; ! /* find next allocated L1 indirect */ err = dnode_next_offset(dn, DNODE_FIND_BACKWARDS, start, 2, 1, 0); ! /* if there are no more, then we are done */ if (err == ESRCH) { ! *start = limit; ! return (0); ! } else if (err) { return (err); } - blkcnt += 1; ! /* reset offset to end of "next" block back */ *start = P2ALIGN(*start, iblkrange); - if (*start <= limit) - *start = limit; - else - *start -= 1; } return (0); } static int dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset, ! uint64_t length, boolean_t free_dnode) { ! dmu_tx_t *tx; ! uint64_t object_size, start, end, len; ! boolean_t trunc = (length == DMU_OBJECT_END); ! int align, err; ! align = 1 << dn->dn_datablkshift; ! ASSERT(align > 0); ! object_size = align == 1 ? dn->dn_datablksz : ! (dn->dn_maxblkid + 1) << dn->dn_datablkshift; ! ! end = offset + length; ! if (trunc || end > object_size) ! end = object_size; ! if (end <= offset) return (0); - length = end - offset; ! while (length) { ! start = end; ! /* assert(offset <= start) */ ! err = get_next_chunk(dn, &start, offset); if (err) return (err); ! len = trunc ? DMU_OBJECT_END : end - start; ! tx = dmu_tx_create(os); ! dmu_tx_hold_free(tx, dn->dn_object, start, len); err = dmu_tx_assign(tx, TXG_WAIT); if (err) { dmu_tx_abort(tx); return (err); } ! dnode_free_range(dn, start, trunc ? -1 : len, tx); ! ! if (start == 0 && free_dnode) { ! ASSERT(trunc); ! dnode_free(dn, tx); } - - length -= end - start; - - dmu_tx_commit(tx); - end = start; - } return (0); } int dmu_free_long_range(objset_t *os, uint64_t object, --- 567,664 ---- /* * Get the next "chunk" of file data to free. We traverse the file from * the end so that the file gets shorter over time (if we crashes in the * middle, this will leave us in a better state). We find allocated file * data by simply searching the allocated level 1 indirects. + * + * On input, *start should be the first offset that does not need to be + * freed (e.g. "offset + length"). On return, *start will be the first + * offset that should be freed. */ static int ! get_next_chunk(dnode_t *dn, uint64_t *start, uint64_t minimum) { ! uint64_t maxblks = DMU_MAX_ACCESS >> (dn->dn_indblkshift + 1); ! /* bytes of data covered by a level-1 indirect block */ uint64_t iblkrange = dn->dn_datablksz * EPB(dn->dn_indblkshift, SPA_BLKPTRSHIFT); ! ASSERT3U(minimum, <=, *start); ! if (*start - minimum <= iblkrange * maxblks) { ! *start = minimum; return (0); } ASSERT(ISP2(iblkrange)); ! for (uint64_t blks = 0; *start > minimum && blks < maxblks; blks++) { int err; ! /* ! * dnode_next_offset(BACKWARDS) will find an allocated L1 ! * indirect block at or before the input offset. We must ! * decrement *start so that it is at the end of the region ! * to search. ! */ ! (*start)--; err = dnode_next_offset(dn, DNODE_FIND_BACKWARDS, start, 2, 1, 0); ! /* if there are no indirect blocks before start, we are done */ if (err == ESRCH) { ! *start = minimum; ! break; ! } else if (err != 0) { return (err); } ! /* set start to the beginning of this L1 indirect */ *start = P2ALIGN(*start, iblkrange); } + if (*start < minimum) + *start = minimum; return (0); } static int dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset, ! uint64_t length) { ! uint64_t object_size = (dn->dn_maxblkid + 1) * dn->dn_datablksz; ! int err; ! if (offset >= object_size) return (0); ! if (length == DMU_OBJECT_END || offset + length > object_size) ! length = object_size - offset; ! ! while (length != 0) { ! uint64_t chunk_end, chunk_begin; ! ! chunk_end = chunk_begin = offset + length; ! ! /* move chunk_begin backwards to the beginning of this chunk */ ! err = get_next_chunk(dn, &chunk_begin, offset); if (err) return (err); ! ASSERT3U(chunk_begin, >=, offset); ! ASSERT3U(chunk_begin, <=, chunk_end); ! dmu_tx_t *tx = dmu_tx_create(os); ! dmu_tx_hold_free(tx, dn->dn_object, ! chunk_begin, chunk_end - chunk_begin); err = dmu_tx_assign(tx, TXG_WAIT); if (err) { dmu_tx_abort(tx); return (err); } + dnode_free_range(dn, chunk_begin, chunk_end - chunk_begin, tx); + dmu_tx_commit(tx); ! length -= chunk_end - chunk_begin; } return (0); } int dmu_free_long_range(objset_t *os, uint64_t object,
*** 673,714 **** int err; err = dnode_hold(os, object, FTAG, &dn); if (err != 0) return (err); ! err = dmu_free_long_range_impl(os, dn, offset, length, FALSE); dnode_rele(dn, FTAG); return (err); } int ! dmu_free_object(objset_t *os, uint64_t object) { - dnode_t *dn; dmu_tx_t *tx; int err; ! err = dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, ! FTAG, &dn); if (err != 0) return (err); ! if (dn->dn_nlevels == 1) { tx = dmu_tx_create(os); dmu_tx_hold_bonus(tx, object); ! dmu_tx_hold_free(tx, dn->dn_object, 0, DMU_OBJECT_END); err = dmu_tx_assign(tx, TXG_WAIT); if (err == 0) { ! dnode_free_range(dn, 0, DMU_OBJECT_END, tx); ! dnode_free(dn, tx); dmu_tx_commit(tx); } else { dmu_tx_abort(tx); } ! } else { ! err = dmu_free_long_range_impl(os, dn, 0, DMU_OBJECT_END, TRUE); ! } ! dnode_rele(dn, FTAG); return (err); } int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset, --- 668,703 ---- int err; err = dnode_hold(os, object, FTAG, &dn); if (err != 0) return (err); ! err = dmu_free_long_range_impl(os, dn, offset, length); dnode_rele(dn, FTAG); return (err); } int ! dmu_free_long_object(objset_t *os, uint64_t object) { dmu_tx_t *tx; int err; ! err = dmu_free_long_range(os, object, 0, DMU_OBJECT_END); if (err != 0) return (err); ! tx = dmu_tx_create(os); dmu_tx_hold_bonus(tx, object); ! dmu_tx_hold_free(tx, object, 0, DMU_OBJECT_END); err = dmu_tx_assign(tx, TXG_WAIT); if (err == 0) { ! err = dmu_object_free(os, object, tx); dmu_tx_commit(tx); } else { dmu_tx_abort(tx); } ! return (err); } int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,