From c39cf5329632f239bbf8fd2b2d32bd4e3cb405a9 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 21 May 2007 11:33:10 +1000 Subject: [PATCH] md: Don't write more than is required of the last page of a bitmap It is possible that real data or metadata follows the bitmap without full page alignment. So limit the last write to be only the required number of bytes, rounded up to the hard sector size of the device. Signed-off-by: Neil Brown Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- drivers/md/bitmap.c | 17 ++++++++++++----- include/linux/raid/bitmap.h | 1 + 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index cef12872508a..550ac7298df7 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -255,19 +255,25 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde } -static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait) +static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait) { mdk_rdev_t *rdev; struct list_head *tmp; + mddev_t *mddev = bitmap->mddev; ITERATE_RDEV(mddev, rdev, tmp) if (test_bit(In_sync, &rdev->flags) - && !test_bit(Faulty, &rdev->flags)) + && !test_bit(Faulty, &rdev->flags)) { + int size = PAGE_SIZE; + if (page->index == bitmap->file_pages-1) + size = roundup(bitmap->last_page_size, + bdev_hardsect_size(rdev->bdev)); md_super_write(mddev, rdev, - (rdev->sb_offset<<1) + offset + (rdev->sb_offset<<1) + bitmap->offset + page->index * (PAGE_SIZE/512), - PAGE_SIZE, + size, page); + } if (wait) md_super_wait(mddev); @@ -282,7 +288,7 @@ static int write_page(struct bitmap *bitmap, struct page *page, int wait) struct buffer_head *bh; if (bitmap->file == NULL) - return write_sb_page(bitmap->mddev, bitmap->offset, page, wait); + return write_sb_page(bitmap, page, wait); bh = page_buffers(page); @@ -923,6 +929,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start) } bitmap->filemap[bitmap->file_pages++] = page; + bitmap->last_page_size = count; } paddr = kmap_atomic(page, KM_USER0); if (bitmap->flags & BITMAP_HOSTENDIAN) diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h index 6db9a4c15355..dd5a05d03d4f 100644 --- a/include/linux/raid/bitmap.h +++ b/include/linux/raid/bitmap.h @@ -232,6 +232,7 @@ struct bitmap { struct page **filemap; /* list of cache pages for the file */ unsigned long *filemap_attr; /* attributes associated w/ filemap pages */ unsigned long file_pages; /* number of pages in the file */ + int last_page_size; /* bytes in the last page */ unsigned long flags; -- cgit v1.2.3