Commit 3b34380ae8c5df6debd85183c7fa1ac05f79b7d2
Committed by
Linus Torvalds
Linus Torvalds
1 parent
03c902e17f
Exists in
master
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4 other branches
[PATCH] md: allow chunk_size to be settable through sysfs
... only before array is started of course. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Showing 2 changed files with 34 additions and 0 deletions Side-by-side Diff
Documentation/md.txt
| ... | ... | @@ -166,6 +166,14 @@ |
| 166 | 166 | will be empty. If an array is being resized (not currently |
| 167 | 167 | possible) this will contain the larger of the old and new sizes. |
| 168 | 168 | |
| 169 | + chunk_size | |
| 170 | + This is the size if bytes for 'chunks' and is only relevant to | |
| 171 | + raid levels that involve striping (1,4,5,6,10). The address space | |
| 172 | + of the array is conceptually divided into chunks and consecutive | |
| 173 | + chunks are striped onto neighbouring devices. | |
| 174 | + The size should be atleast PAGE_SIZE (4k) and should be a power | |
| 175 | + of 2. This can only be set while assembling an array | |
| 176 | + | |
| 169 | 177 | As component devices are added to an md array, they appear in the 'md' |
| 170 | 178 | directory as new directories named |
| 171 | 179 | dev-XXX |
drivers/md/md.c
| ... | ... | @@ -1795,6 +1795,31 @@ |
| 1795 | 1795 | static struct md_sysfs_entry md_raid_disks = __ATTR_RO(raid_disks); |
| 1796 | 1796 | |
| 1797 | 1797 | static ssize_t |
| 1798 | +chunk_size_show(mddev_t *mddev, char *page) | |
| 1799 | +{ | |
| 1800 | + return sprintf(page, "%d\n", mddev->chunk_size); | |
| 1801 | +} | |
| 1802 | + | |
| 1803 | +static ssize_t | |
| 1804 | +chunk_size_store(mddev_t *mddev, const char *buf, size_t len) | |
| 1805 | +{ | |
| 1806 | + /* can only set chunk_size if array is not yet active */ | |
| 1807 | + char *e; | |
| 1808 | + unsigned long n = simple_strtoul(buf, &e, 10); | |
| 1809 | + | |
| 1810 | + if (mddev->pers) | |
| 1811 | + return -EBUSY; | |
| 1812 | + if (!*buf || (*e && *e != '\n')) | |
| 1813 | + return -EINVAL; | |
| 1814 | + | |
| 1815 | + mddev->chunk_size = n; | |
| 1816 | + return len; | |
| 1817 | +} | |
| 1818 | +static struct md_sysfs_entry md_chunk_size = | |
| 1819 | +__ATTR(chunk_size, 0644, chunk_size_show, chunk_size_store); | |
| 1820 | + | |
| 1821 | + | |
| 1822 | +static ssize_t | |
| 1798 | 1823 | action_show(mddev_t *mddev, char *page) |
| 1799 | 1824 | { |
| 1800 | 1825 | char *type = "idle"; |
| ... | ... | @@ -1861,6 +1886,7 @@ |
| 1861 | 1886 | static struct attribute *md_default_attrs[] = { |
| 1862 | 1887 | &md_level.attr, |
| 1863 | 1888 | &md_raid_disks.attr, |
| 1889 | + &md_chunk_size.attr, | |
| 1864 | 1890 | NULL, |
| 1865 | 1891 | }; |
| 1866 | 1892 |