diff options
| author | Martin K. Petersen <martin.petersen@oracle.com> | 2009-05-22 17:17:53 -0400 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-05-22 23:22:55 +0200 |
| commit | c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3 (patch) | |
| tree | a83f7540cc894caafe74db911cba3998d6a9a164 /fs | |
| parent | cd43e26f071524647e660706b784ebcbefbd2e44 (diff) | |
block: Export I/O topology for block devices and partitions
To support devices with physical block sizes bigger than 512 bytes we
need to ensure proper alignment. This patch adds support for exposing
I/O topology characteristics as devices are stacked.
logical_block_size is the smallest unit the device can address.
physical_block_size indicates the smallest I/O the device can write
without incurring a read-modify-write penalty.
The io_min parameter is the smallest preferred I/O size reported by
the device. In many cases this is the same as the physical block
size. However, the io_min parameter can be scaled up when stacking
(RAID5 chunk size > physical block size).
The io_opt characteristic indicates the optimal I/O size reported by
the device. This is usually the stripe width for arrays.
The alignment_offset parameter indicates the number of bytes the start
of the device/partition is offset from the device's natural alignment.
Partition tools and MD/DM utilities can use this to pad their offsets
so filesystems start on proper boundaries.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/partitions/check.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/partitions/check.c b/fs/partitions/check.c index 99e33ef40be4..0af36085eb28 100644 --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -219,6 +219,13 @@ ssize_t part_size_show(struct device *dev, return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects); } +ssize_t part_alignment_offset_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct hd_struct *p = dev_to_part(dev); + return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset); +} + ssize_t part_stat_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -272,6 +279,7 @@ ssize_t part_fail_store(struct device *dev, static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL); static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL); static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL); +static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL); static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL); #ifdef CONFIG_FAIL_MAKE_REQUEST static struct device_attribute dev_attr_fail = @@ -282,6 +290,7 @@ static struct attribute *part_attrs[] = { &dev_attr_partition.attr, &dev_attr_start.attr, &dev_attr_size.attr, + &dev_attr_alignment_offset.attr, &dev_attr_stat.attr, #ifdef CONFIG_FAIL_MAKE_REQUEST &dev_attr_fail.attr, @@ -383,6 +392,7 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno, pdev = part_to_dev(p); p->start_sect = start; + p->alignment_offset = queue_sector_alignment_offset(disk->queue, start); p->nr_sects = len; p->partno = partno; p->policy = get_disk_ro(disk); |