dovecot-1.2: indexes: Fixes to handling shrinking tail offsets.

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-1.2/rev/69ddd7c9c585
changeset: 8811:69ddd7c9c585
user:      Timo Sirainen <tss at iki.fi>
date:      Tue Mar 10 12:28:22 2009 -0400
description:
indexes: Fixes to handling shrinking tail offsets.

diffstat:

4 files changed, 34 insertions(+), 19 deletions(-)
src/lib-index/mail-index-sync.c                |    1 
src/lib-index/mail-index-transaction-private.h |    1 
src/lib-index/mail-transaction-log-append.c    |    7 +++
src/lib-index/mail-transaction-log-file.c      |   44 +++++++++++++-----------

diffs (115 lines):

diff -r b21104f6a752 -r 69ddd7c9c585 src/lib-index/mail-index-sync.c
--- a/src/lib-index/mail-index-sync.c	Tue Mar 10 12:28:00 2009 -0400
+++ b/src/lib-index/mail-index-sync.c	Tue Mar 10 12:28:22 2009 -0400
@@ -461,6 +461,7 @@ int mail_index_sync_begin_to(struct mail
 	if ((ctx->flags & MAIL_INDEX_SYNC_FLAG_AVOID_FLAG_UPDATES) != 0)
 		trans_flags |= MAIL_INDEX_TRANSACTION_FLAG_AVOID_FLAG_UPDATES;
 	ctx->ext_trans = mail_index_transaction_begin(ctx->view, trans_flags);
+	ctx->ext_trans->sync_transaction = TRUE;
 
 	index->syncing = TRUE;
 
diff -r b21104f6a752 -r 69ddd7c9c585 src/lib-index/mail-index-transaction-private.h
--- a/src/lib-index/mail-index-transaction-private.h	Tue Mar 10 12:28:00 2009 -0400
+++ b/src/lib-index/mail-index-transaction-private.h	Tue Mar 10 12:28:22 2009 -0400
@@ -73,6 +73,7 @@ struct mail_index_transaction {
 
 	unsigned int no_appends:1;
 
+	unsigned int sync_transaction:1;
 	unsigned int appends_nonsorted:1;
 	unsigned int pre_hdr_changed:1;
 	unsigned int post_hdr_changed:1;
diff -r b21104f6a752 -r 69ddd7c9c585 src/lib-index/mail-transaction-log-append.c
--- a/src/lib-index/mail-transaction-log-append.c	Tue Mar 10 12:28:00 2009 -0400
+++ b/src/lib-index/mail-transaction-log-append.c	Tue Mar 10 12:28:22 2009 -0400
@@ -523,6 +523,13 @@ static void log_append_sync_offset_if_ne
 	buffer_t *buf;
 	uint32_t offset;
 
+	/* Update the tail offsets only when committing the sync transaction.
+	   Other transactions may not know the latest tail offset and might
+	   end up shrinking it. (Alternatively the shrinking tail offsets could
+	   just be ignored, which would probably work fine too.) */
+	if (!ctx->trans->sync_transaction)
+		return;
+
 	if (ctx->file->max_tail_offset == ctx->file->sync_offset) {
 		/* FIXME: when we remove exclusive log locking, we
 		   can't rely on this. then write non-changed offset + check
diff -r b21104f6a752 -r 69ddd7c9c585 src/lib-index/mail-transaction-log-file.c
--- a/src/lib-index/mail-transaction-log-file.c	Tue Mar 10 12:28:00 2009 -0400
+++ b/src/lib-index/mail-transaction-log-file.c	Tue Mar 10 12:28:22 2009 -0400
@@ -147,8 +147,11 @@ mail_transaction_log_file_skip_to_head(s
 		file->sync_offset = modseq_hdr->log_offset;
 		file->sync_highest_modseq = modseq_hdr->highest_modseq;
 	}
-	file->saved_tail_offset = log->index->map->hdr.log_file_tail_offset;
-	file->saved_tail_sync_offset = file->saved_tail_offset;
+	if (file->hdr.file_seq == log->index->map->hdr.log_file_seq) {
+		file->saved_tail_offset =
+			log->index->map->hdr.log_file_tail_offset;
+		file->saved_tail_sync_offset = file->saved_tail_offset;
+	}
 	if (file->saved_tail_offset > file->max_tail_offset)
 		file->max_tail_offset = file->saved_tail_offset;
 }
@@ -755,9 +758,9 @@ log_file_track_mailbox_sync_offset_hdr(s
 	const unsigned int offset_pos =
 		offsetof(struct mail_index_header, log_file_tail_offset);
 	const unsigned int offset_size = sizeof(ihdr->log_file_tail_offset);
-	uint32_t sync_offset;
-
-	i_assert(offset_size == sizeof(sync_offset));
+	uint32_t tail_offset;
+
+	i_assert(offset_size == sizeof(tail_offset));
 
 	if (size < sizeof(*u) || size < sizeof(*u) + u->size) {
 		mail_transaction_log_file_set_corrupted(file,
@@ -767,28 +770,31 @@ log_file_track_mailbox_sync_offset_hdr(s
 
 	if (u->offset <= offset_pos &&
 	    u->offset + u->size >= offset_pos + offset_size) {
-		memcpy(&sync_offset,
+		memcpy(&tail_offset,
 		       CONST_PTR_OFFSET(u + 1, offset_pos - u->offset),
-		       sizeof(sync_offset));
-
-		if (sync_offset < file->saved_tail_offset) {
+		       sizeof(tail_offset));
+
+		if (tail_offset < file->saved_tail_offset) {
 			if (file->sync_offset < file->saved_tail_sync_offset) {
 				/* saved_tail_offset was already set in header,
 				   but we still had to resync the file to find
 				   modseqs. ignore this record. */
 				return 1;
 			}
-			mail_transaction_log_file_set_corrupted(file,
+			mail_index_set_error(file->log->index,
+				"Transaction log file %s seq %u: "
 				"log_file_tail_offset update shrank it "
-				"(%u vs %"PRIuUOFF_T", file_seq=%u)",
-				sync_offset, file->saved_tail_offset,
-				file->hdr.file_seq);
-			return -1;
-		}
-		file->saved_tail_offset = sync_offset;
-		if (sync_offset > file->max_tail_offset)
-			file->max_tail_offset = sync_offset;
-		return 1;
+				"(%u vs %"PRIuUOFF_T" "
+				"sync_offset=%"PRIuUOFF_T")",
+				file->filepath, file->hdr.file_seq,
+				tail_offset, file->saved_tail_offset,
+				file->sync_offset);
+		} else {
+			file->saved_tail_offset = tail_offset;
+			if (tail_offset > file->max_tail_offset)
+				file->max_tail_offset = tail_offset;
+			return 1;
+		}
 	}
 	return 0;
 }