Re: [PATCH] check bh->b_blocknr only if BH_Mapped is set
[Posted February 11, 2009 by corbet]
| From: |
| Andrew Morton <akpm-AT-linux-foundation.org> |
| To: |
| Nikanth Karthikesan <knikanth-AT-suse.de> |
| Subject: |
| Re: [PATCH] check bh->b_blocknr only if BH_Mapped is set |
| Date: |
| Tue, 10 Feb 2009 12:46:40 -0800 |
| Message-ID: |
| <20090210124640.81d25a27.akpm@linux-foundation.org> |
| Cc: |
| linux-kernel-AT-vger.kernel.org, jens.axboe-AT-oracle.com |
| Archive‑link: | |
Article |
On Mon, 9 Feb 2009 17:48:11 +0530
Nikanth Karthikesan <knikanth@suse.de> wrote:
> check bh->b_blocknr only if BH_Mapped is set
Why?
> diff --git a/fs/buffer.c b/fs/buffer.c
> index 665d446..782c365 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -344,13 +344,13 @@ __find_get_block_slow(struct block_device *bdev,
> sector_t block)
> head = page_buffers(page);
> bh = head;
> do {
> - if (bh->b_blocknr == block) {
> + if (!buffer_mapped(bh))
> + all_mapped = 0;
> + else if (bh->b_blocknr == block) {
> ret = bh;
> get_bh(bh);
> goto out_unlock;
> }
> - if (!buffer_mapped(bh))
> - all_mapped = 0;
> bh = bh->b_this_page;
> } while (bh != head);
Does this fix some user-visible misbehaviour? If so, what was that
behaviour?
Please write good changelogs. This is not some pointless book-keeping
exercise. People will make decisions about which kernel versions
patches should be merged into, and they will want to know if a
particular patch addresses a particular problem which they are
experiencing. For this, they need information.
Thanks.
