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
