2020-06-17 12:00:01

by Zhang Yi

Subject: [PATCH v2 1/5] fs: add bdev writepage hook to block device

Add a new bdev_write_page hook into struct super_operations and called
by bdev_writepage(), which could be used by filesystem to propagate
private handlers.

Signed-off-by: zhangyi (F) <[email protected]>
---
fs/block_dev.c | 5 +++++
include/linux/fs.h | 1 +
2 files changed, 6 insertions(+)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 47860e589388..46e25a4e3ebf 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -606,6 +606,11 @@ EXPORT_SYMBOL(thaw_bdev);

static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
{
+ struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
+
+ if (super && super->s_op->bdev_write_page)
+ return super->s_op->bdev_write_page(page, blkdev_get_block, wbc);
+
return block_write_full_page(page, blkdev_get_block, wbc);
}

diff --git a/include/linux/fs.h b/include/linux/fs.h
index cffc3619eed5..b87b784c6bc6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1983,6 +1983,7 @@ struct super_operations {
struct dquot **(*get_dquots)(struct inode *);
#endif
int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
+ int (*bdev_write_page)(struct page *, get_block_t *, struct writeback_control *);
long (*nr_cached_objects)(struct super_block *,
struct shrink_control *);
long (*free_cached_objects)(struct super_block *,
--
2.25.4

2020-06-18 07:05:19

by Christoph Hellwig

Subject: Re: [PATCH v2 1/5] fs: add bdev writepage hook to block device

On Wed, Jun 17, 2020 at 07:59:43PM +0800, zhangyi (F) wrote:
> Add a new bdev_write_page hook into struct super_operations and called
> by bdev_writepage(), which could be used by filesystem to propagate
> private handlers.

Sorry. but no. We've been trying to get the fs decoupled from the whole
buffer_head crap for quite a while, and this just makes it much worse.
Please don't add layering violations like this.