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pmem: fail io-requests to known bad blocks

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Check the sectors specified in a read bio to see if they hit a known bad
block, and return an error code pmem_do_bvec().

Note that the ->rw_page() is not in a position to return errors.  For
now, copy the same layering violation present in zram_rw_page() to avoid
crashes of the form:

 kernel BUG at mm/filemap.c:822!
 [..]
 Call Trace:
  [<ffffffff811c540e>] page_endio+0x1e/0x60
  [<ffffffff81290d29>] mpage_end_io+0x39/0x60
  [<ffffffff8141c4ef>] bio_endio+0x3f/0x60
  [<ffffffffa005c491>] pmem_make_request+0x111/0x230 [nd_pmem]

...i.e. unlock a page that was already unlocked via pmem_rw_page() =>
page_endio().

Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2016-01-06 12:03:41 -08:00
parent b95f5f4391
commit e10624f8c0
1 changed files with 39 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
drivers/nvdimm/pmem.c
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@ -47,7 +47,20 @@ struct pmem_device {
static int pmem_major;
static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
static bool is_bad_pmem(struct badblocks *bb, sector_t sector, unsigned int len)
{
if (bb->count) {
sector_t first_bad;
int num_bad;
return !!badblocks_check(bb, sector, len / 512, &first_bad,
&num_bad);
}
return false;
}
static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
unsigned int len, unsigned int off, int rw,
sector_t sector)
{
@ -56,6 +69,8 @@ static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
if (rw == READ) {
if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
return -EIO;
memcpy_from_pmem(mem + off, pmem_addr, len);
flush_dcache_page(page);
} else {
@ -64,10 +79,12 @@ static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
}
kunmap_atomic(mem);
return 0;
}
static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
{
int rc = 0;
bool do_acct;
unsigned long start;
struct bio_vec bvec;
@ -76,9 +93,15 @@ static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
struct pmem_device *pmem = bdev->bd_disk->private_data;
do_acct = nd_iostat_start(bio, &start);
bio_for_each_segment(bvec, bio, iter)
pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset,
bio_data_dir(bio), iter.bi_sector);
bio_for_each_segment(bvec, bio, iter) {
rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
bvec.bv_offset, bio_data_dir(bio),
iter.bi_sector);
if (rc) {
bio->bi_error = rc;
break;
}
}
if (do_acct)
nd_iostat_end(bio, start);
@ -93,13 +116,22 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
struct page *page, int rw)
{
struct pmem_device *pmem = bdev->bd_disk->private_data;
int rc;
pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
rc = pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
if (rw & WRITE)
wmb_pmem();
page_endio(page, rw & WRITE, 0);
return 0;
/*
* The ->rw_page interface is subtle and tricky. The core
* retries on any error, so we can only invoke page_endio() in
* the successful completion case. Otherwise, we'll see crashes
* caused by double completion.
*/
if (rc == 0)
page_endio(page, rw & WRITE, 0);
return rc;
}
static long pmem_direct_access(struct block_device *bdev, sector_t sector,