From ab6085c795a71b6a21afe7469d30a365338add7a Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 23 May 2007 13:58:10 -0700 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 5a4a74c1097c..9620d452d030 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; -- 2.20.1