On 2021/1/7 上午1:14, Jan Kara wrote:
On Thu 31-12-20 00:55:59, 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 <ruansy.fnst@xxxxxxxxxxxxxx>Thanks for the patch. Two comments below.diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 4688bff19c20..9f9a2f3bf73b 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;This (and the fs/block_dev.c change below) is just refining the function you've implemented in the patch 6. I think it's confusing to split changes like this - why not implement things correctly from the start in patch 6?
This change added a helper function to find the md devices created on a low-level block device, such as a LVM on /dev/pmem0, and calls ->corrupted_range() for each md device. The md parts were introduced starts from patch 7. So, I add this change in this patch.
diff --git a/fs/block_dev.c b/fs/block_dev.c index 9e84b1928b94..0e50f0e8e8af 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1171,6 +1171,27 @@ 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))) + return -ENODEV;This will not compile for !CONFIG_SYSFS kernels. Not that it would be common but still. Also I'm not sure whether using bd_holder_disks like this is really the right thing to do (when it seems to be only a sysfs thing), although admittedly I'm not aware of a better way of getting this information.
I did a lot of tries and finally found this way. I think I should add a judgement that whether CONFIG_SYSFS is turned on.
-- Thanks, Ruan Shiyang.
Honza+ + list_for_each_entry(holder, &bdev->bd_holder_disks, list) { + disk = holder->disk; + if (disk->fops->corrupted_range) { + rc = disk->fops->corrupted_range(disk, bdev, off, len, data); + if (rc != -ENODEV) + break; + } + } + return rc; +} + static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, struct gendisk *disk) { @@ -1378,6 +1399,22 @@ void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors) } EXPORT_SYMBOL(bd_set_nr_sectors);+int bd_corrupted_range(struct block_device *bdev, loff_t disk_off, loff_t bdev_off, size_t len, void *data)+{ + struct super_block *sb = get_super(bdev); + int rc = 0; + + if (!sb) { + rc = bd_disk_holder_corrupted_range(bdev, disk_off, len, data); + return rc; + } else if (sb->s_op->corrupted_range) + rc = sb->s_op->corrupted_range(sb, bdev, bdev_off, len, data); + drop_super(sb); + + return rc; +} +EXPORT_SYMBOL(bd_corrupted_range); + static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);int bdev_disk_changed(struct block_device *bdev, bool invalidate)diff --git a/include/linux/genhd.h b/include/linux/genhd.h index ed06209008b8..42290470810d 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -376,6 +376,8 @@ void revalidate_disk_size(struct gendisk *disk, bool verbose); bool bdev_check_media_change(struct block_device *bdev); int __invalidate_device(struct block_device *bdev, bool kill_dirty); void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors); +int bd_corrupted_range(struct block_device *bdev, loff_t disk_off, + loff_t bdev_off, size_t len, void *data);/* for drivers/char/raw.c: */int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long); -- 2.29.2
