From c7f8f831a463e9d7d16e43323b71d9e9e187a4c7 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Wed, 25 May 2011 16:09:57 -0700 Subject: [PATCH] Revert "Fix stack traverse_visitbp()" This abomination is no longer required because the zio's issued during this recursive call path will now be handled asynchronously by the taskq thread pool. This reverts commit 6656bf56216f36805731298ee0f4de87ae6b6b3d. --- module/zfs/dmu_traverse.c | 275 ++++++++++++++------------------------ 1 file changed, 98 insertions(+), 177 deletions(-) diff --git a/module/zfs/dmu_traverse.c b/module/zfs/dmu_traverse.c index d262de7d1..998cb4b6a 100644 --- a/module/zfs/dmu_traverse.c +++ b/module/zfs/dmu_traverse.c @@ -59,31 +59,6 @@ typedef struct traverse_data { void *td_arg; } traverse_data_t; -typedef struct traverse_visitbp_data { - /* Function arguments */ - traverse_data_t *tv_td; - const dnode_phys_t *tv_dnp; - arc_buf_t *tv_pbuf; - blkptr_t *tv_bp; - const zbookmark_t *tv_zb; - /* Local variables */ - prefetch_data_t *tv_pd; - zbookmark_t tv_czb; - arc_buf_t *tv_buf; - boolean_t tv_hard; - objset_phys_t *tv_osp; - dnode_phys_t *tv_ldnp; - blkptr_t *tv_cbp; - uint32_t tv_flags; - int tv_err; - int tv_lasterr; - int tv_i; - int tv_epb; - int tv_depth; -} traverse_visitbp_data_t; - -static inline int traverse_visitbp(traverse_data_t *td, const - dnode_phys_t *dnp, arc_buf_t *pbuf, blkptr_t *bp, const zbookmark_t *zb); static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp, arc_buf_t *buf, uint64_t objset, uint64_t object); @@ -153,191 +128,137 @@ traverse_zil(traverse_data_t *td, zil_header_t *zh) zil_free(zilog); } -#define TRAVERSE_VISITBP_MAX_DEPTH 20 - -static void -__traverse_visitbp_init(traverse_visitbp_data_t *tv, - traverse_data_t *td, const dnode_phys_t *dnp, - arc_buf_t *pbuf, blkptr_t *bp, const zbookmark_t *zb, int depth) -{ - tv->tv_td = td; - tv->tv_dnp = dnp; - tv->tv_pbuf = pbuf; - tv->tv_bp = bp; - tv->tv_zb = zb; - tv->tv_err = 0; - tv->tv_lasterr = 0; - tv->tv_buf = NULL; - tv->tv_pd = td->td_pfd; - tv->tv_hard = td->td_flags & TRAVERSE_HARD; - tv->tv_flags = ARC_WAIT; - tv->tv_depth = depth; -} - -static noinline int -__traverse_visitbp(traverse_visitbp_data_t *tv) +static int +traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp, + arc_buf_t *pbuf, blkptr_t *bp, const zbookmark_t *zb) { - ASSERT3S(tv->tv_depth, <, TRAVERSE_VISITBP_MAX_DEPTH); + zbookmark_t czb; + int err = 0, lasterr = 0; + arc_buf_t *buf = NULL; + prefetch_data_t *pd = td->td_pfd; + boolean_t hard = td->td_flags & TRAVERSE_HARD; - if (tv->tv_bp->blk_birth == 0) { - tv->tv_err = tv->tv_td->td_func(tv->tv_td->td_spa, NULL, NULL, - tv->tv_pbuf, tv->tv_zb, tv->tv_dnp, tv->tv_td->td_arg); - return (tv->tv_err); + if (bp->blk_birth == 0) { + err = td->td_func(td->td_spa, NULL, NULL, pbuf, zb, dnp, + td->td_arg); + return (err); } - if (tv->tv_bp->blk_birth <= tv->tv_td->td_min_txg) + if (bp->blk_birth <= td->td_min_txg) return (0); - if (tv->tv_pd && !tv->tv_pd->pd_exited && - ((tv->tv_pd->pd_flags & TRAVERSE_PREFETCH_DATA) || - BP_GET_TYPE(tv->tv_bp) == DMU_OT_DNODE || - BP_GET_LEVEL(tv->tv_bp) > 0)) { - mutex_enter(&tv->tv_pd->pd_mtx); - ASSERT(tv->tv_pd->pd_blks_fetched >= 0); - while (tv->tv_pd->pd_blks_fetched == 0 && !tv->tv_pd->pd_exited) - cv_wait(&tv->tv_pd->pd_cv, &tv->tv_pd->pd_mtx); - tv->tv_pd->pd_blks_fetched--; - cv_broadcast(&tv->tv_pd->pd_cv); - mutex_exit(&tv->tv_pd->pd_mtx); + if (pd && !pd->pd_exited && + ((pd->pd_flags & TRAVERSE_PREFETCH_DATA) || + BP_GET_TYPE(bp) == DMU_OT_DNODE || BP_GET_LEVEL(bp) > 0)) { + mutex_enter(&pd->pd_mtx); + ASSERT(pd->pd_blks_fetched >= 0); + while (pd->pd_blks_fetched == 0 && !pd->pd_exited) + cv_wait(&pd->pd_cv, &pd->pd_mtx); + pd->pd_blks_fetched--; + cv_broadcast(&pd->pd_cv); + mutex_exit(&pd->pd_mtx); } - if (tv->tv_td->td_flags & TRAVERSE_PRE) { - tv->tv_err = tv->tv_td->td_func(tv->tv_td->td_spa, NULL, - tv->tv_bp, tv->tv_pbuf, tv->tv_zb, tv->tv_dnp, - tv->tv_td->td_arg); - if (tv->tv_err == TRAVERSE_VISIT_NO_CHILDREN) + if (td->td_flags & TRAVERSE_PRE) { + err = td->td_func(td->td_spa, NULL, bp, pbuf, zb, dnp, + td->td_arg); + if (err == TRAVERSE_VISIT_NO_CHILDREN) return (0); - if (tv->tv_err) - return (tv->tv_err); + if (err) + return (err); } - if (BP_GET_LEVEL(tv->tv_bp) > 0) { - tv->tv_epb = BP_GET_LSIZE(tv->tv_bp) >> SPA_BLKPTRSHIFT; + if (BP_GET_LEVEL(bp) > 0) { + uint32_t flags = ARC_WAIT; + int i; + blkptr_t *cbp; + int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT; - tv->tv_err = dsl_read(NULL, tv->tv_td->td_spa, tv->tv_bp, - tv->tv_pbuf, arc_getbuf_func, &tv->tv_buf, - ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, - &tv->tv_flags, tv->tv_zb); - if (tv->tv_err) - return (tv->tv_err); + err = dsl_read(NULL, td->td_spa, bp, pbuf, + arc_getbuf_func, &buf, + ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); + if (err) + return (err); /* recursively visitbp() blocks below this */ - tv->tv_cbp = tv->tv_buf->b_data; - for (tv->tv_i = 0; tv->tv_i < tv->tv_epb; - tv->tv_i++, tv->tv_cbp++) { - SET_BOOKMARK(&tv->tv_czb, tv->tv_zb->zb_objset, - tv->tv_zb->zb_object, tv->tv_zb->zb_level - 1, - tv->tv_zb->zb_blkid * tv->tv_epb + tv->tv_i); - __traverse_visitbp_init(tv + 1, tv->tv_td, - tv->tv_dnp, tv->tv_buf, tv->tv_cbp, - &tv->tv_czb, tv->tv_depth + 1); - tv->tv_err = __traverse_visitbp(tv + 1); - if (tv->tv_err) { - if (!tv->tv_hard) + cbp = buf->b_data; + for (i = 0; i < epb; i++, cbp++) { + SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object, + zb->zb_level - 1, + zb->zb_blkid * epb + i); + err = traverse_visitbp(td, dnp, buf, cbp, &czb); + if (err) { + if (!hard) break; - tv->tv_lasterr = tv->tv_err; + lasterr = err; } } - } else if (BP_GET_TYPE(tv->tv_bp) == DMU_OT_DNODE) { - tv->tv_epb = BP_GET_LSIZE(tv->tv_bp) >> DNODE_SHIFT; - - tv->tv_err = dsl_read(NULL, tv->tv_td->td_spa, tv->tv_bp, - tv->tv_pbuf, arc_getbuf_func, &tv->tv_buf, - ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, - &tv->tv_flags, tv->tv_zb); - if (tv->tv_err) - return (tv->tv_err); + } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) { + uint32_t flags = ARC_WAIT; + int i; + int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT; + + err = dsl_read(NULL, td->td_spa, bp, pbuf, + arc_getbuf_func, &buf, + ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); + if (err) + return (err); /* recursively visitbp() blocks below this */ - tv->tv_dnp = tv->tv_buf->b_data; - for (tv->tv_i = 0; tv->tv_i < tv->tv_epb; - tv->tv_i++, tv->tv_dnp++) { - tv->tv_err = traverse_dnode(tv->tv_td, tv->tv_dnp, - tv->tv_buf, tv->tv_zb->zb_objset, - tv->tv_zb->zb_blkid * tv->tv_epb + tv->tv_i); - if (tv->tv_err) { - if (!tv->tv_hard) + dnp = buf->b_data; + for (i = 0; i < epb; i++, dnp++) { + err = traverse_dnode(td, dnp, buf, zb->zb_objset, + zb->zb_blkid * epb + i); + if (err) { + if (!hard) break; - tv->tv_lasterr = tv->tv_err; + lasterr = err; } } - } else if (BP_GET_TYPE(tv->tv_bp) == DMU_OT_OBJSET) { - - tv->tv_err = dsl_read_nolock(NULL, tv->tv_td->td_spa, - tv->tv_bp, arc_getbuf_func, &tv->tv_buf, - ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, - &tv->tv_flags, tv->tv_zb); - if (tv->tv_err) - return (tv->tv_err); - - tv->tv_osp = tv->tv_buf->b_data; - tv->tv_ldnp = &tv->tv_osp->os_meta_dnode; - tv->tv_err = traverse_dnode(tv->tv_td, tv->tv_ldnp, tv->tv_buf, - tv->tv_zb->zb_objset, DMU_META_DNODE_OBJECT); - if (tv->tv_err && tv->tv_hard) { - tv->tv_lasterr = tv->tv_err; - tv->tv_err = 0; + } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) { + uint32_t flags = ARC_WAIT; + objset_phys_t *osp; + dnode_phys_t *dnp; + + err = dsl_read_nolock(NULL, td->td_spa, bp, + arc_getbuf_func, &buf, + ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); + if (err) + return (err); + + osp = buf->b_data; + dnp = &osp->os_meta_dnode; + err = traverse_dnode(td, dnp, buf, zb->zb_objset, + DMU_META_DNODE_OBJECT); + if (err && hard) { + lasterr = err; + err = 0; } - if (tv->tv_err == 0 && - arc_buf_size(tv->tv_buf) >= sizeof (objset_phys_t)) { - tv->tv_ldnp = &tv->tv_osp->os_userused_dnode; - tv->tv_err = traverse_dnode(tv->tv_td, tv->tv_ldnp, - tv->tv_buf, tv->tv_zb->zb_objset, + if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) { + dnp = &osp->os_userused_dnode; + err = traverse_dnode(td, dnp, buf, zb->zb_objset, DMU_USERUSED_OBJECT); } - if (tv->tv_err && tv->tv_hard) { - tv->tv_lasterr = tv->tv_err; - tv->tv_err = 0; + if (err && hard) { + lasterr = err; + err = 0; } - if (tv->tv_err == 0 && - arc_buf_size(tv->tv_buf) >= sizeof (objset_phys_t)) { - tv->tv_ldnp = &tv->tv_osp->os_groupused_dnode; - tv->tv_err = traverse_dnode(tv->tv_td, tv->tv_ldnp, - tv->tv_buf, tv->tv_zb->zb_objset, + if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) { + dnp = &osp->os_groupused_dnode; + err = traverse_dnode(td, dnp, buf, zb->zb_objset, DMU_GROUPUSED_OBJECT); } } - if (tv->tv_buf) - (void) arc_buf_remove_ref(tv->tv_buf, &tv->tv_buf); + if (buf) + (void) arc_buf_remove_ref(buf, &buf); - if (tv->tv_err == 0 && tv->tv_lasterr == 0 && - (tv->tv_td->td_flags & TRAVERSE_POST)) { - tv->tv_err = tv->tv_td->td_func(tv->tv_td->td_spa, NULL, - tv->tv_bp, tv->tv_pbuf, tv->tv_zb, tv->tv_dnp, - tv->tv_td->td_arg); + if (err == 0 && lasterr == 0 && (td->td_flags & TRAVERSE_POST)) { + err = td->td_func(td->td_spa, NULL, bp, pbuf, zb, dnp, + td->td_arg); } - return (tv->tv_err != 0 ? tv->tv_err : tv->tv_lasterr); -} - -/* - * Due to limited stack space recursive functions are frowned upon in - * the Linux kernel. However, they often are the most elegant solution - * to a problem. The following code preserves the recursive function - * traverse_visitbp() but moves the local variables AND function - * arguments to the heap to minimize the stack frame size. Enough - * space is initially allocated on the stack for 16 levels of recursion. - * This change does ugly-up-the-code but it reduces the worst case - * usage from roughly 2496 bytes to 576 bytes on x86_64 archs. - */ -static int -traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp, - arc_buf_t *pbuf, blkptr_t *bp, const zbookmark_t *zb) -{ - traverse_visitbp_data_t *tv; - int error; - - tv = kmem_zalloc(sizeof(traverse_visitbp_data_t) * - TRAVERSE_VISITBP_MAX_DEPTH, KM_SLEEP); - __traverse_visitbp_init(tv, td, dnp, pbuf, bp, zb, 0); - - error = __traverse_visitbp(tv); - - kmem_free(tv, sizeof(traverse_visitbp_data_t) * - TRAVERSE_VISITBP_MAX_DEPTH); - - return (error); + return (err != 0 ? err : lasterr); } static int -- 2.40.0