Add functions dm_bufio_issue_discard and dm_bufio_discard_buffers. dm_bufio_issue_discard sends discard request to the underlying device. dm_bufio_discard_buffers frees buffers in the range and then calls dm_bufio_issue_discard.
Signed-off-by: Mikulas Patocka <[email protected]> --- drivers/md/dm-bufio.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/dm-bufio.h | 12 +++++++++++ 2 files changed, 62 insertions(+) Index: linux-2.6/drivers/md/dm-bufio.c =================================================================== --- linux-2.6.orig/drivers/md/dm-bufio.c 2020-02-07 17:14:08.000000000 +0100 +++ linux-2.6/drivers/md/dm-bufio.c 2020-02-07 17:29:42.000000000 +0100 @@ -1338,6 +1338,56 @@ int dm_bufio_issue_flush(struct dm_bufio 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. * * Then, we write the buffer to the original location if it was dirty. Index: linux-2.6/include/linux/dm-bufio.h =================================================================== --- linux-2.6.orig/include/linux/dm-bufio.h 2020-02-07 17:14:08.000000000 +0100 +++ linux-2.6/include/linux/dm-bufio.h 2020-02-07 17:29:46.000000000 +0100 @@ -126,6 +126,18 @@ int dm_bufio_write_dirty_buffers(struct 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. */ -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
