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 <mpatocka@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
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
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
