diff options
Diffstat (limited to 'module/zfs/dbuf.c')
| -rw-r--r-- | module/zfs/dbuf.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c index 9c60ec55a..95c7b3297 100644 --- a/module/zfs/dbuf.c +++ b/module/zfs/dbuf.c @@ -691,6 +691,14 @@ dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) if (!havepzio) err = zio_wait(zio); } else { + /* + * Another reader came in while the dbuf was in flight + * between UNCACHED and CACHED. Either a writer will finish + * writing the buffer (sending the dbuf to CACHED) or the + * first reader's request will reach the read_done callback + * and send the dbuf to CACHED. Otherwise, a failure + * occurred and the dbuf went to UNCACHED. + */ mutex_exit(&db->db_mtx); if (prefetch) dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, @@ -699,6 +707,7 @@ dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) rw_exit(&dn->dn_struct_rwlock); DB_DNODE_EXIT(db); + /* Skip the wait per the caller's request. */ mutex_enter(&db->db_mtx); if ((flags & DB_RF_NEVERWAIT) == 0) { while (db->db_state == DB_READ || @@ -1313,7 +1322,8 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) } /* - * Return TRUE if this evicted the dbuf. + * Undirty a buffer in the transaction group referenced by the given + * transaction. Return whether this evicted the dbuf. */ static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) @@ -2324,6 +2334,7 @@ dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) ASSERT(db->db_level > 0); DBUF_VERIFY(db); + /* Read the block if it hasn't been read yet. */ if (db->db_buf == NULL) { mutex_exit(&db->db_mtx); (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); @@ -2334,10 +2345,12 @@ dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) DB_DNODE_ENTER(db); dn = DB_DNODE(db); + /* Indirect block size must match what the dnode thinks it is. */ ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); dbuf_check_blkptr(dn, db); DB_DNODE_EXIT(db); + /* Provide the pending dirty record to child dbufs */ db->db_data_pending = dr; mutex_exit(&db->db_mtx); @@ -2728,6 +2741,7 @@ dbuf_write_override_done(zio_t *zio) dbuf_write_done(zio, NULL, db); } +/* Issue I/O to commit a dirty buffer to disk. */ static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) { @@ -2762,11 +2776,19 @@ dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) } if (parent != dn->dn_dbuf) { + /* Our parent is an indirect block. */ + /* We have a dirty parent that has been scheduled for write. */ ASSERT(parent && parent->db_data_pending); + /* Our parent's buffer is one level closer to the dnode. */ ASSERT(db->db_level == parent->db_level-1); + /* + * We're about to modify our parent's db_data by modifying + * our block pointer, so the parent must be released. + */ ASSERT(arc_released(parent->db_buf)); zio = parent->db_data_pending->dr_zio; } else { + /* Our parent is the dnode itself. */ ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && db->db_blkid != DMU_SPILL_BLKID) || (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); |