diff options
Diffstat (limited to 'module/zfs/dmu.c')
| -rw-r--r-- | module/zfs/dmu.c | 44 |
1 files changed, 25 insertions, 19 deletions
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c index f4027af9c..b4133f0e4 100644 --- a/module/zfs/dmu.c +++ b/module/zfs/dmu.c @@ -138,7 +138,7 @@ dmu_buf_hold_noread(objset_t *os, uint64_t object, uint64_t offset, err = dnode_hold(os, object, FTAG, &dn); if (err) return (err); - blkid = dbuf_whichblock(dn, offset); + blkid = dbuf_whichblock(dn, 0, offset); rw_enter(&dn->dn_struct_rwlock, RW_READER); db = dbuf_hold(dn, blkid, tag); rw_exit(&dn->dn_struct_rwlock); @@ -421,7 +421,7 @@ dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset, uint64_t length, dbp = kmem_zalloc(sizeof (dmu_buf_t *) * nblks, KM_SLEEP); zio = zio_root(dn->dn_objset->os_spa, NULL, NULL, ZIO_FLAG_CANFAIL); - blkid = dbuf_whichblock(dn, offset); + blkid = dbuf_whichblock(dn, 0, offset); for (i = 0; i < nblks; i++) { dmu_buf_impl_t *db = dbuf_hold(dn, blkid+i, tag); if (db == NULL) { @@ -522,17 +522,16 @@ dmu_buf_rele_array(dmu_buf_t **dbp_fake, int numbufs, void *tag) } /* - * Issue prefetch i/os for the given blocks. + * Issue prefetch i/os for the given blocks. If level is greater than 0, the + * indirect blocks prefeteched will be those that point to the blocks containing + * the data starting at offset, and continuing to offset + len. * - * Note: The assumption is that we *know* these blocks will be needed - * almost immediately. Therefore, the prefetch i/os will be issued at - * ZIO_PRIORITY_SYNC_READ - * - * Note: indirect blocks and other metadata will be read synchronously, - * causing this function to block if they are not already cached. + * Note that if the indirect blocks above the blocks being prefetched are not in + * cache, they will be asychronously read in. */ void -dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset, uint64_t len) +dmu_prefetch(objset_t *os, uint64_t object, int64_t level, uint64_t offset, + uint64_t len, zio_priority_t pri) { dnode_t *dn; uint64_t blkid; @@ -548,8 +547,9 @@ dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset, uint64_t len) return; rw_enter(&dn->dn_struct_rwlock, RW_READER); - blkid = dbuf_whichblock(dn, object * sizeof (dnode_phys_t)); - dbuf_prefetch(dn, blkid, ZIO_PRIORITY_SYNC_READ); + blkid = dbuf_whichblock(dn, level, + object * sizeof (dnode_phys_t)); + dbuf_prefetch(dn, level, blkid, pri, 0); rw_exit(&dn->dn_struct_rwlock); return; } @@ -564,10 +564,16 @@ dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset, uint64_t len) return; rw_enter(&dn->dn_struct_rwlock, RW_READER); - if (dn->dn_datablkshift) { - int blkshift = dn->dn_datablkshift; - nblks = (P2ROUNDUP(offset + len, 1 << blkshift) - - P2ALIGN(offset, 1 << blkshift)) >> blkshift; + /* + * offset + len - 1 is the last byte we want to prefetch for, and offset + * is the first. Then dbuf_whichblk(dn, level, off + len - 1) is the + * last block we want to prefetch, and dbuf_whichblock(dn, level, + * offset) is the first. Then the number we need to prefetch is the + * last - first + 1. + */ + if (level > 0 || dn->dn_datablkshift != 0) { + nblks = dbuf_whichblock(dn, level, offset + len - 1) - + dbuf_whichblock(dn, level, offset) + 1; } else { nblks = (offset < dn->dn_datablksz); } @@ -575,9 +581,9 @@ dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset, uint64_t len) if (nblks != 0) { int i; - blkid = dbuf_whichblock(dn, offset); + blkid = dbuf_whichblock(dn, level, offset); for (i = 0; i < nblks; i++) - dbuf_prefetch(dn, blkid + i, ZIO_PRIORITY_SYNC_READ); + dbuf_prefetch(dn, level, blkid + i, pri, 0); } rw_exit(&dn->dn_struct_rwlock); @@ -1293,7 +1299,7 @@ dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, arc_buf_t *buf, DB_DNODE_ENTER(dbuf); dn = DB_DNODE(dbuf); rw_enter(&dn->dn_struct_rwlock, RW_READER); - blkid = dbuf_whichblock(dn, offset); + blkid = dbuf_whichblock(dn, 0, offset); VERIFY((db = dbuf_hold(dn, blkid, FTAG)) != NULL); rw_exit(&dn->dn_struct_rwlock); DB_DNODE_EXIT(dbuf); |