Allow shrinking the underlying data device (dm-writecache must be suspended when the device is shrunk).
This patch modifies dm-writecache, so that it doesn't attempt to write any data beyond the end of the data device. Signed-off-by: Mikulas Patocka <[email protected]> Cc: [email protected] --- drivers/md/dm-writecache.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) Index: linux-2.6/drivers/md/dm-writecache.c =================================================================== --- linux-2.6.orig/drivers/md/dm-writecache.c 2021-02-05 20:30:35.000000000 +0100 +++ linux-2.6/drivers/md/dm-writecache.c 2021-02-09 16:50:36.000000000 +0100 @@ -148,6 +148,7 @@ struct dm_writecache { size_t metadata_sectors; size_t n_blocks; uint64_t seq_count; + uint64_t data_device_sectors; void *block_start; struct wc_entry *entries; unsigned block_size; @@ -969,6 +970,8 @@ static void writecache_resume(struct dm_ wc_lock(wc); + wc->data_device_sectors = i_size_read(wc->dev->bdev->bd_inode) >> SECTOR_SHIFT; + if (WC_MODE_PMEM(wc)) { persistent_memory_invalidate_cache(wc->memory_map, wc->memory_map_size); } else { @@ -1638,6 +1641,10 @@ static bool wc_add_block(struct writebac void *address = memory_data(wc, e); persistent_memory_flush_cache(address, block_size); + + if (unlikely(wb->bio.bi_iter.bi_sector + bio_sectors(&wb->bio) >= wc->data_device_sectors)) + return true; + return bio_add_page(&wb->bio, persistent_memory_page(address), block_size, persistent_memory_page_offset(address)) != 0; } @@ -1709,6 +1716,9 @@ static void __writecache_writeback_pmem( if (writecache_has_error(wc)) { bio->bi_status = BLK_STS_IOERR; bio_endio(bio); + } else if (unlikely(!bio_sectors(bio))) { + bio->bi_status = BLK_STS_OK; + bio_endio(bio); } else { submit_bio(bio); } @@ -1752,6 +1762,14 @@ static void __writecache_writeback_ssd(s e = f; } + if (unlikely(to.sector + to.count > wc->data_device_sectors)) { + if (to.sector >= wc->data_device_sectors) { + writecache_copy_endio(0, 0, c); + continue; + } + from.count = to.count = wc->data_device_sectors - to.sector; + } + dm_kcopyd_copy(wc->dm_kcopyd, &from, 1, &to, 0, writecache_copy_endio, c); __writeback_throttle(wc, wbl); -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
