dm bufio: implement discard (6fbeb004) · Commits · 戴 / test

drivers/md/dm-bufio.c

+64 −5

Original line number	Diff line number	Diff line
		@@ -631,6 +631,19 @@ dmio:
		submit_bio(bio);
		}

		static inline sector_t block_to_sector(struct dm_bufio_client *c, sector_t block)
		{
		sector_t sector;

		if (likely(c->sectors_per_block_bits >= 0))
		sector = block << c->sectors_per_block_bits;
		else
		sector = block * (c->block_size >> SECTOR_SHIFT);
		sector += c->start;

		return sector;
		}

		static void submit_io(struct dm_buffer b, int rw, void (end_io)(struct dm_buffer *, blk_status_t))
		{
		unsigned n_sectors;
		@@ -639,11 +652,7 @@ static void submit_io(struct dm_buffer b, int rw, void (end_io)(struct dm_buff

		b->end_io = end_io;

		if (likely(b->c->sectors_per_block_bits >= 0))
		sector = b->block << b->c->sectors_per_block_bits;
		else
		sector = b->block * (b->c->block_size >> SECTOR_SHIFT);
		sector += b->c->start;
		sector = block_to_sector(b->c, b->block);

		if (rw != REQ_OP_WRITE) {
		n_sectors = b->c->block_size >> SECTOR_SHIFT;
		@@ -1325,6 +1334,56 @@ int dm_bufio_issue_flush(struct dm_bufio_client *c)
		}
		EXPORT_SYMBOL_GPL(dm_bufio_issue_flush);

		/*
		* Use dm-io to send a discard request to flush the device.
		*/
		int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t count)
		{
		struct dm_io_request io_req = {
		.bi_op = REQ_OP_DISCARD,
		.bi_op_flags = REQ_SYNC,
		.mem.type = DM_IO_KMEM,
		.mem.ptr.addr = NULL,
		.client = c->dm_io,
		};
		struct dm_io_region io_reg = {
		.bdev = c->bdev,
		.sector = block_to_sector(c, block),
		.count = block_to_sector(c, count),
		};

		BUG_ON(dm_bufio_in_request());

		return dm_io(&io_req, 1, &io_reg, NULL);
		}
		EXPORT_SYMBOL_GPL(dm_bufio_issue_discard);

		/*
		* Free the specified range of buffers. If a buffer is held by other process, it
		* is not freed. If a buffer is dirty, it is discarded without writeback.
		* Finally, send the discard request to the device.
		*/
		int dm_bufio_discard_buffers(struct dm_bufio_client *c, sector_t block, sector_t count)
		{
		sector_t i;

		for (i = block; i < block + count; i++) {
		struct dm_buffer *b;
		dm_bufio_lock(c);
		b = __find(c, i);
		if (b && likely(!b->hold_count)) {
		wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE);
		wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
		__unlink_buffer(b);
		__free_buffer_wake(b);
		}
		dm_bufio_unlock(c);
		}

		return dm_bufio_issue_discard(c, block, count);
		}
		EXPORT_SYMBOL_GPL(dm_bufio_discard_buffers);

		/*
		* We first delete any other buffer that may be at that new location.
		*

include/linux/dm-bufio.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -118,6 +118,18 @@ int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c);
		*/
		int dm_bufio_issue_flush(struct dm_bufio_client *c);

		/*
		* Send a discard request to the underlying device.
		*/
		int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t count);

		/*
		* Free the specified range of buffers. If a buffer is held by other process, it
		* is not freed. If a buffer is dirty, it is discarded without writeback.
		* Finally, send the discard request to the device.
		*/
		int dm_bufio_discard_buffers(struct dm_bufio_client *c, sector_t block, sector_t count);

		/*
		* Like dm_bufio_release but also move the buffer to the new
		* block. dm_bufio_write_dirty_buffers is needed to commit the new block.

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