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path: root/drivers/md/dm-log-writes.c
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Diffstat (limited to 'drivers/md/dm-log-writes.c')
-rw-r--r--drivers/md/dm-log-writes.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 9ea2b0291f20..e549392e0ea5 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -60,6 +60,7 @@
#define WRITE_LOG_VERSION 1ULL
#define WRITE_LOG_MAGIC 0x6a736677736872ULL
+#define WRITE_LOG_SUPER_SECTOR 0
/*
* The disk format for this is braindead simple.
@@ -115,6 +116,7 @@ struct log_writes_c {
struct list_head logging_blocks;
wait_queue_head_t wait;
struct task_struct *log_kthread;
+ struct completion super_done;
};
struct pending_block {
@@ -180,6 +182,14 @@ static void log_end_io(struct bio *bio)
bio_put(bio);
}
+static void log_end_super(struct bio *bio)
+{
+ struct log_writes_c *lc = bio->bi_private;
+
+ complete(&lc->super_done);
+ log_end_io(bio);
+}
+
/*
* Meant to be called if there is an error, it will free all the pages
* associated with the block.
@@ -215,7 +225,8 @@ static int write_metadata(struct log_writes_c *lc, void *entry,
bio->bi_iter.bi_size = 0;
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, lc->logdev->bdev);
- bio->bi_end_io = log_end_io;
+ bio->bi_end_io = (sector == WRITE_LOG_SUPER_SECTOR) ?
+ log_end_super : log_end_io;
bio->bi_private = lc;
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
@@ -418,11 +429,18 @@ static int log_super(struct log_writes_c *lc)
super.nr_entries = cpu_to_le64(lc->logged_entries);
super.sectorsize = cpu_to_le32(lc->sectorsize);
- if (write_metadata(lc, &super, sizeof(super), NULL, 0, 0)) {
+ if (write_metadata(lc, &super, sizeof(super), NULL, 0,
+ WRITE_LOG_SUPER_SECTOR)) {
DMERR("Couldn't write super");
return -1;
}
+ /*
+ * Super sector should be writen in-order, otherwise the
+ * nr_entries could be rewritten incorrectly by an old bio.
+ */
+ wait_for_completion_io(&lc->super_done);
+
return 0;
}
@@ -531,6 +549,7 @@ static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
INIT_LIST_HEAD(&lc->unflushed_blocks);
INIT_LIST_HEAD(&lc->logging_blocks);
init_waitqueue_head(&lc->wait);
+ init_completion(&lc->super_done);
atomic_set(&lc->io_blocks, 0);
atomic_set(&lc->pending_blocks, 0);