Re: [PATCH v2 08/10] md: Implement ->corrupted_range()

2021-01-25 Thread Guoqing Jiang




On 1/25/21 23:55, Shiyang Ruan wrote:

With the support of ->rmap(), it is possible to obtain the superblock on
a mapped device.

If a pmem device is used as one target of mapped device, we cannot
obtain its superblock directly.  With the help of SYSFS, the mapped
device can be found on the target devices.  So, we iterate the
bdev->bd_holder_disks to obtain its mapped device.

Signed-off-by: Shiyang Ruan 
---
  drivers/md/dm.c   | 61 +++
  drivers/nvdimm/pmem.c | 11 +++-
  fs/block_dev.c| 42 -
  include/linux/genhd.h |  2 ++
  4 files changed, 107 insertions(+), 9 deletions(-)


I can't see md raid is involved here, perhaps dm-devel need to be cced 
instead of raid list. And the subject need to be changed as well.


Thanks,
Guoqing
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[PATCH v2 08/10] md: Implement ->corrupted_range()

2021-01-25 Thread Shiyang Ruan
With the support of ->rmap(), it is possible to obtain the superblock on
a mapped device.

If a pmem device is used as one target of mapped device, we cannot
obtain its superblock directly.  With the help of SYSFS, the mapped
device can be found on the target devices.  So, we iterate the
bdev->bd_holder_disks to obtain its mapped device.

Signed-off-by: Shiyang Ruan 
---
 drivers/md/dm.c   | 61 +++
 drivers/nvdimm/pmem.c | 11 +++-
 fs/block_dev.c| 42 -
 include/linux/genhd.h |  2 ++
 4 files changed, 107 insertions(+), 9 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7bac564f3faa..31b0c340b695 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -507,6 +507,66 @@ static int dm_blk_report_zones(struct gendisk *disk, 
sector_t sector,
 #define dm_blk_report_zonesNULL
 #endif /* CONFIG_BLK_DEV_ZONED */
 
+struct corrupted_hit_info {
+   struct block_device *bdev;
+   sector_t offset;
+};
+
+static int dm_blk_corrupted_hit(struct dm_target *ti, struct dm_dev *dev,
+   sector_t start, sector_t count, void *data)
+{
+   struct corrupted_hit_info *bc = data;
+
+   return bc->bdev == (void *)dev->bdev &&
+   (start <= bc->offset && bc->offset < start + count);
+}
+
+struct corrupted_do_info {
+   size_t length;
+   void *data;
+};
+
+static int dm_blk_corrupted_do(struct dm_target *ti, struct block_device *bdev,
+  sector_t disk_sect, void *data)
+{
+   struct corrupted_do_info *bc = data;
+   loff_t disk_off = to_bytes(disk_sect);
+   loff_t bdev_off = to_bytes(disk_sect - get_start_sect(bdev));
+
+   return bd_corrupted_range(bdev, disk_off, bdev_off, bc->length, 
bc->data);
+}
+
+static int dm_blk_corrupted_range(struct gendisk *disk,
+ struct block_device *target_bdev,
+ loff_t target_offset, size_t len, void *data)
+{
+   struct mapped_device *md = disk->private_data;
+   struct dm_table *map;
+   struct dm_target *ti;
+   sector_t target_sect = to_sector(target_offset);
+   struct corrupted_hit_info hi = {target_bdev, target_sect};
+   struct corrupted_do_info di = {len, data};
+   int srcu_idx, i, rc = -ENODEV;
+
+   map = dm_get_live_table(md, _idx);
+   if (!map)
+   return rc;
+
+   for (i = 0; i < dm_table_get_num_targets(map); i++) {
+   ti = dm_table_get_target(map, i);
+   if (!(ti->type->iterate_devices && ti->type->rmap))
+   continue;
+   if (!ti->type->iterate_devices(ti, dm_blk_corrupted_hit, ))
+   continue;
+
+   rc = ti->type->rmap(ti, target_sect, dm_blk_corrupted_do, );
+   break;
+   }
+
+   dm_put_live_table(md, srcu_idx);
+   return rc;
+}
+
 static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
struct block_device **bdev)
 {
@@ -3062,6 +3122,7 @@ static const struct block_device_operations dm_blk_dops = 
{
.getgeo = dm_blk_getgeo,
.report_zones = dm_blk_report_zones,
.pr_ops = _pr_ops,
+   .corrupted_range = dm_blk_corrupted_range,
.owner = THIS_MODULE
 };
 
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 501959947d48..3d9f4ccbbd9e 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -256,21 +256,16 @@ static int pmem_rw_page(struct block_device *bdev, 
sector_t sector,
 static int pmem_corrupted_range(struct gendisk *disk, struct block_device 
*bdev,
loff_t disk_offset, size_t len, void *data)
 {
-   struct super_block *sb;
loff_t bdev_offset;
sector_t disk_sector = disk_offset >> SECTOR_SHIFT;
-   int rc = 0;
+   int rc = -ENODEV;
 
bdev = bdget_disk_sector(disk, disk_sector);
if (!bdev)
-   return -ENODEV;
+   return rc;
 
bdev_offset = (disk_sector - get_start_sect(bdev)) << SECTOR_SHIFT;
-   sb = get_super(bdev);
-   if (sb && sb->s_op->corrupted_range) {
-   rc = sb->s_op->corrupted_range(sb, bdev, bdev_offset, len, 
data);
-   drop_super(sb);
-   }
+   rc = bd_corrupted_range(bdev, bdev_offset, bdev_offset, len, data);
 
bdput(bdev);
return rc;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 3b8963e228a1..3cc2b2911e3a 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1079,6 +1079,27 @@ struct bd_holder_disk {
int refcnt;
 };
 
+static int bd_disk_holder_corrupted_range(struct block_device *bdev, loff_t 
off,
+ size_t len, void *data)
+{
+   struct bd_holder_disk *holder;
+   struct gendisk *disk;
+   int rc = 0;
+
+   if (list_empty(&(bdev->bd_holder_disks)))
+