This is a note to let you know that I've just added the patch titled dm writecache: fix writing beyond end of underlying device when shrinking to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-writecache-fix-writing-beyond-end-of-underlying-device-when-shrinking.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4134455f2aafdfeab50cabb4cccb35e916034b93 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka <mpatocka@xxxxxxxxxx> Date: Tue, 9 Feb 2021 10:56:20 -0500 Subject: dm writecache: fix writing beyond end of underlying device when shrinking From: Mikulas Patocka <mpatocka@xxxxxxxxxx> commit 4134455f2aafdfeab50cabb4cccb35e916034b93 upstream. Do not attempt to write any data beyond the end of the underlying data device while shrinking it. The DM writecache device must be suspended when the underlying data device is shrunk. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm-writecache.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -142,6 +142,7 @@ struct dm_writecache { size_t metadata_sectors; size_t n_blocks; uint64_t seq_count; + sector_t data_device_sectors; void *block_start; struct wc_entry *entries; unsigned block_size; @@ -929,6 +930,8 @@ 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 { @@ -1499,6 +1502,10 @@ static bool wc_add_block(struct writebac void *address = memory_data(wc, e); persistent_memory_flush_cache(address, block_size); + + if (unlikely(bio_end_sector(&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; } @@ -1571,6 +1578,9 @@ static void __writecache_writeback_pmem( if (writecache_has_error(wc)) { bio->bi_status = BLK_STS_IOERR; bio_endio(&wb->bio); + } else if (unlikely(!bio_sectors(&wb->bio))) { + bio->bi_status = BLK_STS_OK; + bio_endio(&wb->bio); } else { submit_bio(&wb->bio); } @@ -1614,6 +1624,14 @@ 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); Patches currently in stable-queue which might be from mpatocka@xxxxxxxxxx are queue-4.19/dm-writecache-return-the-exact-table-values-that-were-set.patch queue-4.19/dm-writecache-fix-writing-beyond-end-of-underlying-device-when-shrinking.patch