Commit f6af949c authored by NeilBrown's avatar NeilBrown

md: support bitmap offset appropriate for external-metadata arrays.

For md arrays were metadata is managed externally, the kernel does not
know about a superblock so the superblock offset is 0.
If we want to have a write-intent-bitmap near the end of the
devices of such an array, we should support sector_t sized offset.
We need offset be possibly negative for when the bitmap is before
the metadata, so use loff_t instead.

Also add sanity check that bitmap does not overlap with data.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 9cd30fdc
...@@ -212,7 +212,7 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page) ...@@ -212,7 +212,7 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
*/ */
/* IO operations when bitmap is stored near all superblocks */ /* IO operations when bitmap is stored near all superblocks */
static struct page *read_sb_page(mddev_t *mddev, long offset, static struct page *read_sb_page(mddev_t *mddev, loff_t offset,
struct page *page, struct page *page,
unsigned long index, int size) unsigned long index, int size)
{ {
...@@ -287,14 +287,22 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait) ...@@ -287,14 +287,22 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
while ((rdev = next_active_rdev(rdev, mddev)) != NULL) { while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
int size = PAGE_SIZE; int size = PAGE_SIZE;
long offset = mddev->bitmap_info.offset; loff_t offset = mddev->bitmap_info.offset;
if (page->index == bitmap->file_pages-1) if (page->index == bitmap->file_pages-1)
size = roundup(bitmap->last_page_size, size = roundup(bitmap->last_page_size,
bdev_logical_block_size(rdev->bdev)); bdev_logical_block_size(rdev->bdev));
/* Just make sure we aren't corrupting data or /* Just make sure we aren't corrupting data or
* metadata * metadata
*/ */
if (offset < 0) { if (mddev->external) {
/* Bitmap could be anywhere. */
if (rdev->sb_start + offset + (page->index *(PAGE_SIZE/512)) >
rdev->data_offset &&
rdev->sb_start + offset <
rdev->data_offset + mddev->dev_sectors +
(PAGE_SIZE/512))
goto bad_alignment;
} else if (offset < 0) {
/* DATA BITMAP METADATA */ /* DATA BITMAP METADATA */
if (offset if (offset
+ (long)(page->index * (PAGE_SIZE/512)) + (long)(page->index * (PAGE_SIZE/512))
......
...@@ -282,11 +282,13 @@ struct mddev_s ...@@ -282,11 +282,13 @@ struct mddev_s
struct bitmap *bitmap; /* the bitmap for the device */ struct bitmap *bitmap; /* the bitmap for the device */
struct { struct {
struct file *file; /* the bitmap file */ struct file *file; /* the bitmap file */
long offset; /* offset from superblock of loff_t offset; /* offset from superblock of
* start of bitmap. May be * start of bitmap. May be
* negative, but not '0' * negative, but not '0'
* For external metadata, offset
* from start of device.
*/ */
long default_offset; /* this is the offset to use when loff_t default_offset; /* this is the offset to use when
* hot-adding a bitmap. It should * hot-adding a bitmap. It should
* eventually be settable by sysfs. * eventually be settable by sysfs.
*/ */
......
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