... only before array is started of course.
Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./Documentation/md.txt | 8 ++++++++
./drivers/md/md.c | 26 ++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
diff ./Documentation/md.txt~current~ ./Documentation/md.txt
--- ./Documentation/md.txt~current~ 2005-12-12 11:30:58.000000000 +1100
+++ ./Documentation/md.txt 2005-12-12 11:31:25.000000000 +1100
@@ -166,6 +166,14 @@ All md devices contain:
will be empty. If an array is being resized (not currently
possible) this will contain the larger of the old and new sizes.
+ chunk_size
+ This is the size if bytes for 'chunks' and is only relevant to
+ raid levels that involve striping (1,4,5,6,10). The address space
+ of the array is conceptually divided into chunks and consecutive
+ chunks are striped onto neighbouring devices.
+ The size should be atleast PAGE_SIZE (4k) and should be a power
+ of 2. This can only be set while assembling an array
+
As component devices are added to an md array, they appear in the 'md'
directory as new directories named
dev-XXX
diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~ 2005-12-12 11:30:58.000000000 +1100
+++ ./drivers/md/md.c 2005-12-12 11:31:25.000000000 +1100
@@ -1795,6 +1795,31 @@ raid_disks_show(mddev_t *mddev, char *pa
static struct md_sysfs_entry md_raid_disks = __ATTR_RO(raid_disks);
static ssize_t
+chunk_size_show(mddev_t *mddev, char *page)
+{
+ return sprintf(page, "%d\n", mddev->chunk_size);
+}
+
+static ssize_t
+chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
+{
+ /* can only set chunk_size if array is not yet active */
+ char *e;
+ unsigned long n = simple_strtoul(buf, &e, 10);
+
+ if (mddev->pers)
+ return -EBUSY;
+ if (!*buf || (*e && *e != '\n'))
+ return -EINVAL;
+
+ mddev->chunk_size = n;
+ return len;
+}
+static struct md_sysfs_entry md_chunk_size =
+__ATTR(chunk_size, 0644, chunk_size_show, chunk_size_store);
+
+
+static ssize_t
action_show(mddev_t *mddev, char *page)
{
char *type = "idle";
@@ -1861,6 +1886,7 @@ md_mismatches = __ATTR_RO(mismatch_cnt);
static struct attribute *md_default_attrs[] = {
&md_level.attr,
&md_raid_disks.attr,
+ &md_chunk_size.attr,
NULL,
};
-
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