dm writecache: handle DAX to partitions on persistent memory correctly (f9e040ef) · Commits · 戴 / test

The function dax_direct_access doesn't take partitions into account, it always maps pages from the beginning of the device. Therefore, persistent_memory_claim() must get the partition offset using get_start_sect() and add it to the page offsets passed to dax_direct_access(). Signed-off-by:

Mikulas Patocka <mpatocka@redhat.com> Fixes: ("dm: add writecache target") Cc: stable@vger.kernel.org # 4.18+ Signed-off-by:

Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-writecache.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -231,6 +231,7 @@ static int persistent_memory_claim(struct dm_writecache *wc)
		pfn_t pfn;
		int id;
		struct page **pages;
		sector_t offset;

		wc->memory_vmapped = false;

		@@ -245,9 +246,16 @@ static int persistent_memory_claim(struct dm_writecache *wc)
		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(struct dm_writecache *wc)
		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;

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