在 2008-08-11一的 15:53 +0530，Aneesh Kumar K.V写道：
> We are a bit agressive in invalidating all the pages. But
> it is ok because we really don't know why the block allocation
> failed and it is better to come of the writeback path
> so that user can look for more info.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Added to unstable patch queue for more testing.
> ---
> fs/ext4/inode.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 62 insertions(+), 1 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 26e30ed..e437a5b 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1761,6 +1761,39 @@ static inline void __unmap_underlying_blocks(struct inode *inode,
> unmap_underlying_metadata(bdev, bh->b_blocknr + i);
> }
>
> +static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
> + sector_t logical, long blk_cnt)
> +{
> + int nr_pages, i;
> + pgoff_t index, end;
> + struct pagevec pvec;
> + struct inode *inode = mpd->inode;
> + struct address_space *mapping = inode->i_mapping;
> +
> + index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
> + end = (logical + blk_cnt - 1) >>
> + (PAGE_CACHE_SHIFT - inode->i_blkbits);
> + while (index <= end) {
> + nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
> + if (nr_pages == 0)
> + break;
> + for (i = 0; i < nr_pages; i++) {
> + struct page *page = pvec.pages[i];
> + index = page->index;
> + if (index > end)
> + break;
> + index++;
> +
> + BUG_ON(!PageLocked(page));
> + BUG_ON(PageWriteback(page));
> + block_invalidatepage(page, 0);
> + ClearPageUptodate(page);
> + unlock_page(page);
> + }
> + }
> + return;
> +}
> +
> /*
> * mpage_da_map_blocks - go through given space
> *
> @@ -1794,8 +1827,36 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
> if (!new.b_size)
> return;
> err = mpd->get_block(mpd->inode, next, &new, 1);
> - if (err)
> + if (err) {
> +
> + /* If get block returns with error
> + * we simply return. Later writepage
> + * will redirty the page and writepages
> + * will find the dirty page again
> + */
> + if (err == -EAGAIN)
> + return;
> + /*
> + * get block failure will cause us
> + * to loop in writepages. Because
> + * a_ops->writepage won't be able to
> + * make progress. The page will be redirtied
> + * by writepage and writepages will again
> + * try to write the same.
> + */
> + printk(KERN_EMERG "%s block allocation failed for inode %lu "
> + "at logical offset %llu with max blocks "
> + "%zd with error %d\n",
> + __func__, mpd->inode->i_ino,
> + (unsigned long long)next,
> + lbh->b_size >> mpd->inode->i_blkbits, err);
> + printk(KERN_EMERG "This should not happen.!! "
> + "Data will be lost\n");
> + /* invlaidate all the pages */
> + ext4_da_block_invalidatepages(mpd, next,
> + lbh->b_size >> mpd->inode->i_blkbits);
> return;
> + }
> BUG_ON(new.b_size == 0);
>
> if (buffer_new(&new))
--
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