This patch fixes handling partitions in the dm-writecache target. The
function dax_direct_access doesn't take partitions into account, it always
maps pages from the beginning of the device. Therefore, we must get the
partition offset using the function get_start_sect and add it to the page
offsets passed to dax_direct_access.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 4.18+
Fixes: 48debafe4f2f ("dm: add writecache target")
---
drivers/md/dm-writecache.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
Index: linux-2.6/drivers/md/dm-writecache.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-writecache.c 2020-08-19 15:04:21.499999000 +0200
+++ linux-2.6/drivers/md/dm-writecache.c 2020-08-24 17:07:54.169999000 +0200
@@ -231,6 +231,7 @@ static int persistent_memory_claim(struc
pfn_t pfn;
int id;
struct page **pages;
+ sector_t offset;
wc->memory_vmapped = false;
@@ -245,9 +246,16 @@ static int persistent_memory_claim(struc
goto err1;
}
+ offset = get_start_sect(wc->ssd_dev->bdev);
+ if (offset & (PAGE_SIZE / 512 - 1)) {
+ r = -EINVAL;
+ goto err1;
+ }
+ offset >>= PAGE_SHIFT - 9;
+
id = dax_read_lock();
- da = dax_direct_access(wc->ssd_dev->dax_dev, 0, p, &wc->memory_map, &pfn);
+ da = dax_direct_access(wc->ssd_dev->dax_dev, offset, p, &wc->memory_map, &pfn);
if (da < 0) {
wc->memory_map = NULL;
r = da;
@@ -269,7 +277,7 @@ static int persistent_memory_claim(struc
i = 0;
do {
long daa;
- daa = dax_direct_access(wc->ssd_dev->dax_dev, i, p - i,
+ daa = dax_direct_access(wc->ssd_dev->dax_dev, offset + i, p - i,
NULL, &pfn);
if (daa <= 0) {
r = daa ? daa : -EINVAL;
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
