From: Christoph Hellwig <hch@infradead.org>
To: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
nvdimm@lists.linux.dev, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, djwong@kernel.org,
dan.j.williams@intel.com, david@fromorbit.com, hch@infradead.org,
jane.chu@oracle.com
Subject: Re: [PATCH v12 7/7] fsdax: set a CoW flag when associate reflink mappings
Date: Sun, 10 Apr 2022 23:55:35 -0700 [thread overview]
Message-ID: <YlPQ59w4L4pnDYWq@infradead.org> (raw)
In-Reply-To: <20220410160904.3758789-8-ruansy.fnst@fujitsu.com>
> + * Set or Update the page->mapping with FS_DAX_MAPPING_COW flag.
> + * Return true if it is an Update.
> + */
> +static inline bool dax_mapping_set_cow(struct page *page)
> +{
> + if (page->mapping) {
> + /* flag already set */
> + if (dax_mapping_is_cow(page->mapping))
> + return false;
> +
> + /*
> + * This page has been mapped even before it is shared, just
> + * need to set this FS_DAX_MAPPING_COW flag.
> + */
> + dax_mapping_set_cow_flag(&page->mapping);
> + return true;
> + }
> + /* Newly associate CoW mapping */
> + dax_mapping_set_cow_flag(&page->mapping);
> + return false;
Given that this is the only place calling dax_mapping_set_cow I wonder
if we should just open code it here, and also lift the page->index logic
from the caller into this helper.
static inline void dax_mapping_set_cow(struct page *page)
{
if ((uintptr_t)page->mapping != PAGE_MAPPING_DAX_COW) {
/*
* Reset the index if the page was already mapped
* regularly before.
*/
if (page->mapping)
page->index = 1;
page->mapping = (void *)PAGE_MAPPING_DAX_COW;
}
page->index++;
}
> + if (!dax_mapping_is_cow(page->mapping)) {
> + /* keep the CoW flag if this page is still shared */
> + if (page->index-- > 0)
> + continue;
> + } else
> + WARN_ON_ONCE(page->mapping && page->mapping != mapping);
Isnt the dax_mapping_is_cow check above inverted?
prev parent reply other threads:[~2022-04-11 6:55 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-10 16:08 [PATCH v12 0/7] fsdax: introduce fs query to support reflink Shiyang Ruan
2022-04-10 16:08 ` [PATCH v12 1/7] dax: Introduce holder for dax_device Shiyang Ruan
2022-04-11 6:35 ` Christoph Hellwig
2022-04-12 23:22 ` Dan Williams
2022-04-10 16:08 ` [PATCH v12 2/7] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2022-04-10 19:48 ` kernel test robot
2022-04-10 20:19 ` kernel test robot
2022-04-11 6:37 ` Christoph Hellwig
2022-04-11 9:39 ` Shiyang Ruan
2022-04-10 16:09 ` [PATCH v12 3/7] pagemap,pmem: Introduce ->memory_failure() Shiyang Ruan
2022-04-10 16:09 ` [PATCH v12 4/7] fsdax: Introduce dax_lock_mapping_entry() Shiyang Ruan
2022-04-10 16:09 ` [PATCH v12 5/7] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2022-04-11 6:40 ` wangjianjian (C)
2022-04-11 9:40 ` Shiyang Ruan
2022-04-10 16:09 ` [PATCH v12 6/7] xfs: Implement ->notify_failure() for XFS Shiyang Ruan
2022-04-10 18:58 ` kernel test robot
2022-04-10 23:54 ` kernel test robot
2022-04-11 6:39 ` Christoph Hellwig
2022-04-13 0:04 ` Dave Chinner
2022-04-13 2:06 ` Dan Williams
2022-04-13 6:09 ` Dave Chinner
2022-04-13 17:09 ` Dan Williams
2022-04-13 17:12 ` Christoph Hellwig
2022-04-14 13:22 ` [xfs] bf68be0c39: BUG:KASAN:null-ptr-deref_in_fs_put_dax kernel test robot
2022-04-10 16:09 ` [PATCH v12 7/7] fsdax: set a CoW flag when associate reflink mappings Shiyang Ruan
2022-04-11 6:55 ` Christoph Hellwig [this message]
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