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pma: mmap and mprotect revisions wip

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This commit is contained in:
barter-simsum 2023-12-12 18:23:37 -05:00
parent 9271deb3d6
commit e96d7ecb4c
1 changed files with 125 additions and 18 deletions
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143
rust/ares_pma/c-src/btree.c
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@ -382,6 +382,7 @@ _bt_nalloc(BT_state *state)
params to the function and make actual return value an error code. This is
to avoid forcing some callers to immediately use _fo_get */
BT_nlistnode **n = &state->nlist;
BT_page *ret = 0;
for (; *n; n = &(*n)->next) {
/* ;;: this assert is temporary. When partition striping is
@ -396,7 +397,7 @@ _bt_nalloc(BT_state *state)
BT_page *ret;
ret = (*n)->va;
*n = (*n)->next;
return ret;
break;
}
/* larger than necessary: shrink the node */
if ((*n)->sz > 1) {
@ -404,9 +405,12 @@ _bt_nalloc(BT_state *state)
ret = (*n)->va;
(*n)->sz -= 1;
(*n)->va = (*n)->va + 1;
return ret;
break;
}
}
/* make node writeable */
mprotect(ret, sizeof(BT_page), PROT_READ | PROT_WRITE);
}
static int
@ -1494,6 +1498,7 @@ _flist_grow(BT_state *state, BT_flistnode *space)
static int
_flist_new(BT_state *state)
#define FLIST_PG_START (((BT_PAGESIZE * BT_NUMMETAS) + BLK_BASE_LEN0) / BT_PAGESIZE)
{
BT_meta *meta = state->meta_pages[state->which];
BT_page *root = _node_get(state, meta->root);
@ -1507,8 +1512,7 @@ _flist_new(BT_state *state)
head->next = 0;
head->sz = len;
head->pg = PMA_GROW_SIZE; /* ;;: should we invoke logic to expand the backing file
here? probably. implement it */ /* */
head->pg = FLIST_PG_START;
state->flist = head;
return BT_SUCC;
@ -2022,15 +2026,30 @@ _bt_state_restore_maps2(BT_state *state, BT_page *node,
size_t bytelen = hiaddr - loaddr;
off_t offset = P2BYTES(pg);
if (loaddr !=
mmap(loaddr,
bytelen,
PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_SHARED,
state->data_fd,
offset)) {
DPRINTF("mmap: failed to map at addr %p", loaddr);
abort();
if (pg != 0) {
/* not freespace, map readonly data on disk */
if (loaddr !=
mmap(loaddr,
bytelen,
PROT_READ,
MAP_FIXED | MAP_SHARED,
state->data_fd,
offset)) {
DPRINTF("mmap: failed to map at addr %p", loaddr);
abort();
}
}
else {
/* freespace, map no access */
if (loaddr !=
mmap(loaddr,
bytelen,
PROT_NONE,
MAP_FIXED | MAP_ANONYMOUS | MAP_NORESERVE,
-1, 0)) {
DPRINTF("mmap: failed to map at addr %p", loaddr);
abort();
}
}
}
return;
@ -2224,8 +2243,10 @@ _bt_state_load(BT_state *state)
}
state->map = mmap(BT_MAPADDR,
BT_ADDRSIZE,
PROT_READ | PROT_WRITE,
BT_ADDRSIZE, /* should actually just be first 2M
stripe. and then from there
should map like it's freespace. */
PROT_READ | PROT_WRITE, /* ;;: PROT_READ */
MAP_FIXED | MAP_SHARED,
state->data_fd,
0);
@ -2392,6 +2413,13 @@ _bt_sync_meta(BT_state *state)
/* zero the new metapage's checksum */
newwhich = state->which ? 0 : 1;
newmeta = state->meta_pages[newwhich];
/* make new metapage writeable */
if (mprotect(newmeta, sizeof(BT_page), PROT_READ | PROT_WRITE) != 0) {
DPRINTF("mprotect of new metapage failed with %s", strerror(errno));
abort();
}
newmeta->chk = 0;
/* copy over metapage to new metapage excluding the checksum */
@ -2407,9 +2435,15 @@ _bt_sync_meta(BT_state *state)
newmeta->root = newrootpg;
/* finally, switch the metapage we're referring to */
/* switch the metapage we're referring to */
state->which = newwhich;
/* finally, make old metapage read-only */
if (mprotect(meta, sizeof(BT_page), PROT_READ) != 0) {
DPRINTF("mprotect of old metapage failed with %s", strerror(errno));
abort();
}
return BT_SUCC;
}
@ -2424,7 +2458,7 @@ _bt_sync(BT_state *state, BT_page *node, uint8_t depth, uint8_t maxdepth)
/* leaf */
if (depth == maxdepth) {
_bt_sync_leaf(state, node);
return BT_SUCC;
goto e;
}
/* do dfs */
@ -2442,10 +2476,17 @@ _bt_sync(BT_state *state, BT_page *node, uint8_t depth, uint8_t maxdepth)
if (msync(child, sizeof(BT_page), MS_SYNC))
return errno;
/* clean the child */
/* unset child dirty bit */
_bt_cleanchild(node, i);
}
e:
/* all modifications done in node, mark it read-only */
if (mprotect(node, sizeof(BT_page), PROT_READ) != 0) {
DPRINTF("mprotect of node failed with %s", strerror(errno));
abort();
}
return BT_SUCC;
}
@ -2572,6 +2613,20 @@ bt_free(BT_state *state, void *lo, void *hi)
vaof_t hioff = addr2off(hi);
_bt_insert(state, looff, hioff, 0);
_mlist_insert(state, lo, hi);
/* ;;: is this correct? Shouldn't this actually happen when we merge the
pending_mlist on sync? */
size_t bytelen = (BYTE *)hi - (BYTE *)lo;
if (lo !=
mmap(lo,
bytelen,
PROT_NONE,
MAP_ANONYMOUS | MAP_FIXED | MAP_NORESERVE,
-1, 0)) {
DPRINTF("mmap: failed to map at addr %p", lo);
abort();
}
}
// XX need to mprotect PROT_READ all ranges synced including root/meta
@ -2595,6 +2650,12 @@ bt_sync(BT_state *state)
if (msync(root, sizeof(BT_page), MS_SYNC))
return errno;
/* make root read-only */
if (mprotect(root, sizeof(BT_page), PROT_READ) != 0) {
DPRINTF("mprotect of root failed with %s", strerror(errno));
abort();
}
/* then sync the metapage */
if (rc = _bt_sync_meta(state))
return rc;
@ -2920,3 +2981,49 @@ _bt_printnode(BT_page *node)
printf("[%5zu] %10x %10x\n", i, node->datk[i].va, node->datk[i].fo);
}
}
/*
_bt_state_restore_maps2
if pg 0:
mmap MAP_ANONYMOUS | MAP_FIXED | MAP_NO_RESERVE
PROT_NONE
if pg !0:
mmap MAP_SHARED | MAP_FIXED
PROT_READ
------------------
the three routines that make modification to the data maps are:
bt_malloc:
MAP_SHARED | MAP_FIXED
PROT_READ | PROT_WRITE
_bt_data_cow:
MAP_SHARED | MAP_FIXED
PROT_READ | PROT_WRITE
bt_sync:
(mprotect)
PROT_READ
bt_free:
MAP_ANONYMOUS | MAP_FIXED | MAP_NO_RESERVE
PROT_NONE
-----------------
8 linear mappings (striping)
when we _bt_nalloc, mprotect(PROT_READ | PROT_WRITE)
when we free a node: mprotect(PROT_NONE)
additionally, when we sync, all allocated nodes: mprotect(PROT_READ)
*/