static
void
write_mrecord(int fdout, uint32_t type, hammer_ioc_mrecord_any_t mrec,
int bytes)
{
char zbuf[HAMMER_HEAD_ALIGN];
int pad;
pad = HAMMER_HEAD_DOALIGN(bytes) - bytes;
assert(bytes >= (int)sizeof(mrec->head));
bzero(&mrec->head, sizeof(mrec->head));
mrec->head.signature = HAMMER_IOC_MIRROR_SIGNATURE;
mrec->head.type = type;
mrec->head.rec_size = bytes;
hammer_crc_set_mrec_head(&mrec->head, bytes);
if (write(fdout, mrec, bytes) != bytes) {
fprintf(stderr, "write_mrecord: error %d (%s)\n",
errno, strerror(errno));
exit(1);
}
if (pad) {
bzero(zbuf, pad);
if (write(fdout, zbuf, pad) != pad) {
fprintf(stderr, "write_mrecord: error %d (%s)\n",
errno, strerror(errno));
exit(1);
}
}
}
/*
* All B-Tree records within the specified key range which also conform
* to the transaction id range are returned. Mirroring code keeps track
* of the last transaction id fully scanned and can efficiently pick up
* where it left off if interrupted.
*
* The PFS is identified in the mirror structure. The passed ip is just
* some directory in the overall HAMMER filesystem and has nothing to
* do with the PFS.
*/
int
hammer_ioc_mirror_read(hammer_transaction_t trans, hammer_inode_t ip,
struct hammer_ioc_mirror_rw *mirror)
{
struct hammer_cmirror cmirror;
struct hammer_cursor cursor;
union hammer_ioc_mrecord_any mrec;
hammer_btree_leaf_elm_t elm;
char *uptr;
int error;
int data_len;
int bytes;
int eatdisk;
int mrec_flags;
uint32_t localization;
hammer_crc_t rec_crc;
localization = pfs_to_lo(mirror->pfs_id);
if ((mirror->key_beg.localization | mirror->key_end.localization) &
HAMMER_LOCALIZE_PSEUDOFS_MASK) {
return(EINVAL);
}
if (hammer_btree_cmp(&mirror->key_beg, &mirror->key_end) > 0)
return(EINVAL);
mirror->key_cur = mirror->key_beg;
mirror->key_cur.localization &= HAMMER_LOCALIZE_MASK;
mirror->key_cur.localization |= localization;
bzero(&mrec, sizeof(mrec));
bzero(&cmirror, sizeof(cmirror));
/*
* Make CRC errors non-fatal (at least on data), causing an EDOM
* error instead of EIO.
*/
trans->flags |= HAMMER_TRANSF_CRCDOM;
retry:
error = hammer_init_cursor(trans, &cursor, NULL, NULL);
if (error) {
hammer_done_cursor(&cursor);
goto failed;
}
cursor.key_beg = mirror->key_cur;
cursor.key_end = mirror->key_end;
cursor.key_end.localization &= HAMMER_LOCALIZE_MASK;
cursor.key_end.localization |= localization;
cursor.flags |= HAMMER_CURSOR_END_INCLUSIVE;
cursor.flags |= HAMMER_CURSOR_BACKEND;
/*
* This flag filters the search to only return elements whos create
* or delete TID is >= mirror_tid. The B-Tree uses the mirror_tid
* field stored with internal and leaf nodes to shortcut the scan.
*/
cursor.flags |= HAMMER_CURSOR_MIRROR_FILTERED;
cursor.cmirror = &cmirror;
cmirror.mirror_tid = mirror->tid_beg;
error = hammer_btree_first(&cursor);
while (error == 0) {
/*
* Yield to more important tasks
*/
if (error == 0) {
error = hammer_signal_check(trans->hmp);
if (error)
break;
}
/*
* An internal node can be returned in mirror-filtered
* mode and indicates that the scan is returning a skip
* range in the cursor->cmirror structure.
*/
uptr = (char *)mirror->ubuf + mirror->count;
if (cursor.node->ondisk->type == HAMMER_BTREE_TYPE_INTERNAL) {
/*
* Check space
*/
mirror->key_cur = cmirror.skip_beg;
bytes = sizeof(mrec.skip);
if (mirror->count + HAMMER_HEAD_DOALIGN(bytes) >
mirror->size) {
break;
}
/*
* Fill mrec
*/
mrec.head.signature = HAMMER_IOC_MIRROR_SIGNATURE;
mrec.head.type = HAMMER_MREC_TYPE_SKIP;
mrec.head.rec_size = bytes;
mrec.skip.skip_beg = cmirror.skip_beg;
mrec.skip.skip_end = cmirror.skip_end;
hammer_crc_set_mrec_head(&mrec.head, bytes);
error = copyout(&mrec, uptr, bytes);
eatdisk = 0;
goto didwrite;
}
/*
* Leaf node. In full-history mode we could filter out
* elements modified outside the user-requested TID range.
*
* However, such elements must be returned so the writer
* can compare them against the target to determine what
* needs to be deleted on the target, particular for
* no-history mirrors.
*/
KKASSERT(cursor.node->ondisk->type == HAMMER_BTREE_TYPE_LEAF);
elm = &cursor.node->ondisk->elms[cursor.index].leaf;
mirror->key_cur = elm->base;
/*
* If the record was created after our end point we just
* ignore it.
*/
if (elm->base.create_tid > mirror->tid_end) {
error = 0;
bytes = 0;
eatdisk = 1;
goto didwrite;
}
/*
* Determine if we should generate a PASS or a REC. PASS
* records are records without any data payload. Such
* records will be generated if the target is already expected
* to have the record, allowing it to delete the gaps.
*
* A PASS record is also used to perform deletions on the
* target.
*
* Such deletions are needed if the master or files on the
* master are no-history, or if the slave is so far behind
* the master has already been pruned.
*/
if (elm->base.create_tid < mirror->tid_beg) {
bytes = sizeof(mrec.rec);
if (mirror->count + HAMMER_HEAD_DOALIGN(bytes) >
mirror->size) {
break;
}
/*
* Fill mrec.
*/
mrec.head.signature = HAMMER_IOC_MIRROR_SIGNATURE;
mrec.head.type = HAMMER_MREC_TYPE_PASS;
mrec.head.rec_size = bytes;
mrec.rec.leaf = *elm;
hammer_crc_set_mrec_head(&mrec.head, bytes);
error = copyout(&mrec, uptr, bytes);
eatdisk = 1;
goto didwrite;
}
/*
* The core code exports the data to userland.
*
* CRC errors on data are reported but passed through,
* but the data must be washed by the user program.
*
* If userland just wants the btree records it can
* request that bulk data not be returned. This is
* use during mirror-stream histogram generation.
*/
mrec_flags = 0;
data_len = (elm->data_offset) ? elm->data_len : 0;
if (data_len &&
(mirror->head.flags & HAMMER_IOC_MIRROR_NODATA)) {
data_len = 0;
mrec_flags |= HAMMER_MRECF_NODATA;
}
if (data_len) {
error = hammer_btree_extract_data(&cursor);
if (error) {
if (error != EDOM)
break;
mrec_flags |= HAMMER_MRECF_CRC_ERROR |
HAMMER_MRECF_DATA_CRC_BAD;
}
}
bytes = sizeof(mrec.rec) + data_len;
if (mirror->count + HAMMER_HEAD_DOALIGN(bytes) > mirror->size)
break;
/*
* Construct the record for userland and copyout.
*
* The user is asking for a snapshot, if the record was
* deleted beyond the user-requested ending tid, the record
* is not considered deleted from the point of view of
* userland and delete_tid is cleared.
*/
mrec.head.signature = HAMMER_IOC_MIRROR_SIGNATURE;
mrec.head.type = HAMMER_MREC_TYPE_REC | mrec_flags;
mrec.head.rec_size = bytes;
mrec.rec.leaf = *elm;
if (elm->base.delete_tid > mirror->tid_end)
mrec.rec.leaf.base.delete_tid = 0;
rec_crc = hammer_crc_get_mrec_head(&mrec.head, sizeof(mrec.rec));
if (data_len)
rec_crc = crc32_ext(cursor.data, data_len, rec_crc);
mrec.head.rec_crc = rec_crc;
error = copyout(&mrec, uptr, sizeof(mrec.rec));
if (data_len && error == 0) {
error = copyout(cursor.data, uptr + sizeof(mrec.rec),
data_len);
}
eatdisk = 1;
/*
* eatdisk controls whether we skip the current cursor
* position on the next scan or not. If doing a SKIP
* the cursor is already positioned properly for the next
* scan and eatdisk will be 0.
*/
didwrite:
if (error == 0) {
mirror->count += HAMMER_HEAD_DOALIGN(bytes);
if (eatdisk)
cursor.flags |= HAMMER_CURSOR_ATEDISK;
else
cursor.flags &= ~HAMMER_CURSOR_ATEDISK;
error = hammer_btree_iterate(&cursor);
}
}
if (error == ENOENT) {
mirror->key_cur = mirror->key_end;
error = 0;
}
hammer_done_cursor(&cursor);
if (error == EDEADLK)
goto retry;
if (error == EINTR) {
mirror->head.flags |= HAMMER_IOC_HEAD_INTR;
error = 0;
}
failed:
mirror->key_cur.localization &= HAMMER_LOCALIZE_MASK;
return(error);
}
