mdbox-sync.c revision 96088ba9ef3b6c113a0a41f3778cd38f437ddc3d
/* Copyright (c) 2007-2016 Dovecot authors, see the included COPYING file */
/*
Expunging works like:
1. Lock map index by beginning a map sync.
2. Write map UID refcount changes to map index (=> tail != head).
3. Expunge messages from mailbox index.
4. Finish map sync, which updates tail=head and unlocks map index.
If something crashes after 2 but before 4 is finished, tail != head and
reader can do a full resync to figure out what got broken.
*/
#include "lib.h"
#include "array.h"
#include "ioloop.h"
#include "str.h"
#include "mdbox-storage.h"
#include "mdbox-storage-rebuild.h"
#include "mdbox-map.h"
#include "mdbox-file.h"
#include "mdbox-sync.h"
#include "mailbox-recent-flags.h"
static int
dbox_sync_verify_expunge_guid(struct mdbox_sync_context *ctx, uint32_t seq,
const guid_128_t guid_128)
{
const void *data;
uint32_t uid;
mail_index_lookup_uid(ctx->sync_view, seq, &uid);
mail_index_lookup_ext(ctx->sync_view, seq,
ctx->mbox->guid_ext_id, &data, NULL);
if (guid_128_is_empty(guid_128) ||
memcmp(data, guid_128, GUID_128_SIZE) == 0)
return 0;
mail_storage_set_critical(&ctx->mbox->storage->storage.storage,
"Mailbox %s: Expunged GUID mismatch for UID %u: %s vs %s",
ctx->mbox->box.vname, uid,
guid_128_to_string(data), guid_128_to_string(guid_128));
mdbox_storage_set_corrupted(ctx->mbox->storage);
return -1;
}
static int mdbox_sync_expunge(struct mdbox_sync_context *ctx, uint32_t seq,
const guid_128_t guid_128)
{
uint32_t map_uid;
if (seq_range_array_add(&ctx->expunged_seqs, seq)) {
/* already marked as expunged in this sync */
return 0;
}
if (dbox_sync_verify_expunge_guid(ctx, seq, guid_128) < 0)
return -1;
if (mdbox_mail_lookup(ctx->mbox, ctx->sync_view, seq, &map_uid) < 0)
return -1;
if (mdbox_map_update_refcount(ctx->map_trans, map_uid, -1) < 0)
return -1;
return 0;
}
static int mdbox_sync_rec(struct mdbox_sync_context *ctx,
const struct mail_index_sync_rec *sync_rec)
{
uint32_t seq, seq1, seq2;
if (sync_rec->type != MAIL_INDEX_SYNC_TYPE_EXPUNGE) {
/* not interested */
return 0;
}
if (!mail_index_lookup_seq_range(ctx->sync_view,
sync_rec->uid1, sync_rec->uid2,
&seq1, &seq2)) {
/* already expunged everything. nothing to do. */
return 0;
}
for (seq = seq1; seq <= seq2; seq++) {
if (mdbox_sync_expunge(ctx, seq, sync_rec->guid_128) < 0)
return -1;
}
return 0;
}
static int dbox_sync_mark_expunges(struct mdbox_sync_context *ctx)
{
enum mail_index_transaction_flags flags =
MAIL_INDEX_TRANSACTION_FLAG_EXTERNAL;
struct mailbox *box = &ctx->mbox->box;
struct mail_index_transaction *trans;
struct seq_range_iter iter;
unsigned int n;
const void *data;
uint32_t seq, uid;
/* use a separate transaction here so that we can commit the changes
during map transaction */
trans = mail_index_transaction_begin(ctx->sync_view, flags);
seq_range_array_iter_init(&iter, &ctx->expunged_seqs); n = 0;
while (seq_range_array_iter_nth(&iter, n++, &seq)) {
mail_index_lookup_uid(ctx->sync_view, seq, &uid);
mail_index_lookup_ext(ctx->sync_view, seq,
ctx->mbox->guid_ext_id, &data, NULL);
mail_index_expunge_guid(trans, seq, data);
}
if (mail_index_transaction_commit(&trans) < 0)
return -1;
if (box->v.sync_notify != NULL) {
/* do notifications after commit finished successfully */
box->tmp_sync_view = ctx->sync_view;
seq_range_array_iter_init(&iter, &ctx->expunged_seqs); n = 0;
while (seq_range_array_iter_nth(&iter, n++, &seq)) {
mail_index_lookup_uid(ctx->sync_view, seq, &uid);
box->v.sync_notify(box, uid, MAILBOX_SYNC_TYPE_EXPUNGE);
}
box->tmp_sync_view = NULL;
}
return 0;
}
static int mdbox_sync_index(struct mdbox_sync_context *ctx)
{
struct mailbox *box = &ctx->mbox->box;
const struct mail_index_header *hdr;
struct mail_index_sync_rec sync_rec;
uint32_t seq1, seq2;
int ret = 0;
hdr = mail_index_get_header(ctx->sync_view);
if (hdr->uid_validity == 0) {
/* newly created index file */
if (hdr->next_uid == 1) {
/* could be just a race condition where we opened the
mailbox between mkdir and index creation. fix this
silently. */
if (mdbox_mailbox_create_indexes(box, NULL, ctx->trans) < 0)
return -1;
return 1;
}
mail_storage_set_critical(box->storage,
"Mailbox %s: Broken index: missing UIDVALIDITY",
box->vname);
return 0;
}
/* mark the newly seen messages as recent */
if (mail_index_lookup_seq_range(ctx->sync_view, hdr->first_recent_uid,
hdr->next_uid, &seq1, &seq2)) {
mailbox_recent_flags_set_seqs(&ctx->mbox->box, ctx->sync_view,
seq1, seq2);
}
/* handle syncing records without map being locked. */
if (mdbox_map_atomic_is_locked(ctx->atomic)) {
ctx->map_trans = mdbox_map_transaction_begin(ctx->atomic, FALSE);
i_array_init(&ctx->expunged_seqs, 64);
}
while (mail_index_sync_next(ctx->index_sync_ctx, &sync_rec)) {
if ((ret = mdbox_sync_rec(ctx, &sync_rec)) < 0)
break;
}
/* write refcount changes to map index. transaction commit updates the
log head, while tail is left behind. */
if (mdbox_map_atomic_is_locked(ctx->atomic)) {
if (ret == 0)
ret = mdbox_map_transaction_commit(ctx->map_trans, "mdbox syncing");
/* write changes to mailbox index */
if (ret == 0)
ret = dbox_sync_mark_expunges(ctx);
/* finish the map changes and unlock the map. this also updates
map's tail -> head. */
if (ret < 0)
mdbox_map_atomic_set_failed(ctx->atomic);
mdbox_map_transaction_free(&ctx->map_trans);
ctx->expunged_count = seq_range_count(&ctx->expunged_seqs);
array_free(&ctx->expunged_seqs);
}
if (box->v.sync_notify != NULL)
box->v.sync_notify(box, 0, 0);
return ret == 0 ? 1 :
(ctx->mbox->storage->corrupted ? 0 : -1);
}
static int mdbox_sync_try_begin(struct mdbox_sync_context *ctx,
enum mail_index_sync_flags sync_flags)
{
struct mdbox_mailbox *mbox = ctx->mbox;
int ret;
ret = index_storage_expunged_sync_begin(&mbox->box, &ctx->index_sync_ctx,
&ctx->sync_view, &ctx->trans, sync_flags);
if (mail_index_reset_fscked(mbox->box.index))
mdbox_storage_set_corrupted(mbox->storage);
if (ret <= 0)
return ret; /* error / nothing to do */
if (!mdbox_map_atomic_is_locked(ctx->atomic) &&
mail_index_sync_has_expunges(ctx->index_sync_ctx)) {
/* we have expunges, so we need to write to map.
it needs to be locked before mailbox index. */
mail_index_sync_set_reason(ctx->index_sync_ctx, "mdbox expunge check");
mail_index_sync_rollback(&ctx->index_sync_ctx);
index_storage_expunging_deinit(&ctx->mbox->box);
if (mdbox_map_atomic_lock(ctx->atomic, "mdbox syncing with expunges") < 0)
return -1;
return mdbox_sync_try_begin(ctx, sync_flags);
}
return 1;
}
int mdbox_sync_begin(struct mdbox_mailbox *mbox, enum mdbox_sync_flags flags,
struct mdbox_map_atomic_context *atomic,
struct mdbox_sync_context **ctx_r)
{
struct mail_storage *storage = mbox->box.storage;
const struct mail_index_header *hdr =
mail_index_get_header(mbox->box.view);
struct mdbox_sync_context *ctx;
const char *reason;
enum mail_index_sync_flags sync_flags;
int ret;
bool rebuild, storage_rebuilt = FALSE;
*ctx_r = NULL;
/* avoid race conditions with mailbox creation, don't check for dbox
headers until syncing has locked the mailbox */
rebuild = mbox->storage->corrupted ||
(hdr->flags & MAIL_INDEX_HDR_FLAG_FSCKD) != 0 ||
mdbox_map_is_fscked(mbox->storage->map) ||
(flags & MDBOX_SYNC_FLAG_FORCE_REBUILD) != 0;
if (rebuild && (flags & MDBOX_SYNC_FLAG_NO_REBUILD) == 0) {
if (mdbox_storage_rebuild_in_context(mbox->storage, atomic) < 0)
return -1;
mailbox_recent_flags_reset(&mbox->box);
storage_rebuilt = TRUE;
}
ctx = i_new(struct mdbox_sync_context, 1);
ctx->mbox = mbox;
ctx->flags = flags;
ctx->atomic = atomic;
sync_flags = index_storage_get_sync_flags(&mbox->box);
if (!rebuild && (flags & MDBOX_SYNC_FLAG_FORCE) == 0)
sync_flags |= MAIL_INDEX_SYNC_FLAG_REQUIRE_CHANGES;
if ((flags & MDBOX_SYNC_FLAG_FSYNC) != 0)
sync_flags |= MAIL_INDEX_SYNC_FLAG_FSYNC;
/* don't write unnecessary dirty flag updates */
sync_flags |= MAIL_INDEX_SYNC_FLAG_AVOID_FLAG_UPDATES;
ret = mdbox_sync_try_begin(ctx, sync_flags);
if (ret <= 0) {
/* failed / nothing to do */
index_storage_expunging_deinit(&mbox->box);
i_free(ctx);
return ret;
}
if ((ret = mdbox_sync_index(ctx)) <= 0) {
mail_index_sync_set_reason(ctx->index_sync_ctx,
ret < 0 ? "mdbox syncing failed" :
"mdbox syncing found corruption");
mail_index_sync_rollback(&ctx->index_sync_ctx);
index_storage_expunging_deinit(&mbox->box);
i_free_and_null(ctx);
if (ret < 0)
return -1;
/* corrupted */
if (storage_rebuilt) {
mail_storage_set_critical(storage,
"mdbox %s: Storage keeps breaking",
mailbox_get_path(&mbox->box));
return -1;
}
/* we'll need to rebuild storage.
try again from the beginning. */
mdbox_storage_set_corrupted(mbox->storage);
if ((flags & MDBOX_SYNC_FLAG_NO_REBUILD) != 0) {
mail_storage_set_critical(storage,
"mdbox %s: Can't rebuild storage",
mailbox_get_path(&mbox->box));
return -1;
}
return mdbox_sync_begin(mbox, flags, atomic, ctx_r);
}
index_storage_expunging_deinit(&mbox->box);
if (!mdbox_map_atomic_is_locked(ctx->atomic))
reason = "mdbox synced";
else {
/* may be 0 msgs, but that still informs that the map
was locked */
reason = t_strdup_printf("mdbox synced - %u msgs expunged",
ctx->expunged_count);
}
mail_index_sync_set_reason(ctx->index_sync_ctx, reason);
*ctx_r = ctx;
return 0;
}
int mdbox_sync_finish(struct mdbox_sync_context **_ctx, bool success)
{
struct mdbox_sync_context *ctx = *_ctx;
int ret = success ? 0 : -1;
*_ctx = NULL;
if (success) {
if (mail_index_sync_commit(&ctx->index_sync_ctx) < 0) {
mailbox_set_index_error(&ctx->mbox->box);
ret = -1;
}
} else {
mail_index_sync_rollback(&ctx->index_sync_ctx);
}
i_free(ctx);
return ret;
}
int mdbox_sync(struct mdbox_mailbox *mbox, enum mdbox_sync_flags flags)
{
struct mdbox_sync_context *sync_ctx;
struct mdbox_map_atomic_context *atomic;
int ret;
atomic = mdbox_map_atomic_begin(mbox->storage->map);
ret = mdbox_sync_begin(mbox, flags, atomic, &sync_ctx);
if (ret == 0 && sync_ctx != NULL)
ret = mdbox_sync_finish(&sync_ctx, TRUE);
if (ret == 0)
mdbox_map_atomic_set_success(atomic);
if (mdbox_map_atomic_finish(&atomic) < 0)
ret = -1;
return ret;
}
struct mailbox_sync_context *
mdbox_storage_sync_init(struct mailbox *box, enum mailbox_sync_flags flags)
{
struct mdbox_mailbox *mbox = (struct mdbox_mailbox *)box;
enum mdbox_sync_flags mdbox_sync_flags = 0;
int ret = 0;
if (!box->opened) {
if (mailbox_open(box) < 0)
ret = -1;
}
if (box->opened) {
if (mail_index_reset_fscked(box->index))
mdbox_storage_set_corrupted(mbox->storage);
}
if (ret == 0 && (index_mailbox_want_full_sync(&mbox->box, flags) ||
mbox->storage->corrupted)) {
if ((flags & MAILBOX_SYNC_FLAG_FORCE_RESYNC) != 0)
mdbox_sync_flags |= MDBOX_SYNC_FLAG_FORCE_REBUILD;
ret = mdbox_sync(mbox, mdbox_sync_flags);
}
return index_mailbox_sync_init(box, flags, ret < 0);
}