dm snapshot: refactor __find_pending_exception (2913808e) · Commits · 戴 / test

drivers/md/dm-snap.c

+28 −24

Original line number	Diff line number	Diff line
		@@ -972,6 +972,17 @@ static void start_copy(struct dm_snap_pending_exception *pe)
		&src, 1, &dest, 0, copy_callback, pe);
		}

		static struct dm_snap_pending_exception *
		__lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk)
		{
		struct dm_snap_exception *e = lookup_exception(&s->pending, chunk);

		if (!e)
		return NULL;

		return container_of(e, struct dm_snap_pending_exception, e);
		}

		/*
		* Looks to see if this snapshot already has a pending exception
		* for this chunk, otherwise it allocates a new one and inserts
		@@ -983,20 +994,9 @@ static void start_copy(struct dm_snap_pending_exception *pe)
		static struct dm_snap_pending_exception *
		__find_pending_exception(struct dm_snapshot s, struct bio bio)
		{
		struct dm_snap_exception *e;
		struct dm_snap_pending_exception *pe;
		struct dm_snap_pending_exception pe, pe2;
		chunk_t chunk = sector_to_chunk(s, bio->bi_sector);

		/*
		* Is there a pending exception for this already ?
		*/
		e = lookup_exception(&s->pending, chunk);
		if (e) {
		/* cast the exception to a pending exception */
		pe = container_of(e, struct dm_snap_pending_exception, e);
		goto out;
		}

		/*
		* Create a new pending exception, we don't want
		* to hold the lock while we do this.
		@@ -1010,11 +1010,10 @@ __find_pending_exception(struct dm_snapshot s, struct bio bio)
		return NULL;
		}

		e = lookup_exception(&s->pending, chunk);
		if (e) {
		pe2 = __lookup_pending_exception(s, chunk);
		if (pe2) {
		free_pending_exception(pe);
		pe = container_of(e, struct dm_snap_pending_exception, e);
		goto out;
		return pe2;
		}

		pe->e.old_chunk = chunk;
		@@ -1032,7 +1031,6 @@ __find_pending_exception(struct dm_snapshot s, struct bio bio)
		get_pending_exception(pe);
		insert_exception(&s->pending, &pe->e);

		out:
		return pe;
		}

		@@ -1083,12 +1081,15 @@ static int snapshot_map(struct dm_target ti, struct bio bio,
		* writeable.
		*/
		if (bio_rw(bio) == WRITE) {
		pe = __lookup_pending_exception(s, chunk);
		if (!pe) {
		pe = __find_pending_exception(s, bio);
		if (!pe) {
		__invalidate_snapshot(s, -ENOMEM);
		r = -EIO;
		goto out_unlock;
		}
		}

		remap_exception(s, &pe->e, bio, chunk);
		bio_list_add(&pe->snapshot_bios, bio);
		@@ -1217,11 +1218,14 @@ static int __origin_write(struct list_head snapshots, struct bio bio)
		if (e)
		goto next_snapshot;

		pe = __lookup_pending_exception(snap, chunk);
		if (!pe) {
		pe = __find_pending_exception(snap, bio);
		if (!pe) {
		__invalidate_snapshot(snap, -ENOMEM);
		goto next_snapshot;
		}
		}

		if (!primary_pe) {
		/*

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