diff mbox series

ceph: Convert ceph_writepages_start() to use folios a little more

Message ID 20230605165418.2909336-1-willy@infradead.org (mailing list archive)
State New, archived
Headers show
Series ceph: Convert ceph_writepages_start() to use folios a little more | expand

Commit Message

Matthew Wilcox June 5, 2023, 4:54 p.m. UTC
After we iterate through the locked folios using filemap_get_folios_tag(),
we currently convert back to a page (and then in some circumstaces back
to a folio again!).  Just use a folio throughout and avoid various hidden
calls to compound_head().  Ceph still uses a page array to interact with
the OSD which should be cleaned up in a subsequent patch.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/ceph/addr.c | 79 +++++++++++++++++++++++++-------------------------
 1 file changed, 39 insertions(+), 40 deletions(-)

Comments

Xiubo Li June 6, 2023, 5:37 a.m. UTC | #1
This Looks good to me.

BTW, could you rebase this to the 'testing' branch ? This will introduce 
a lots of conflicts with the fscrypt patches, I'd prefer this could be 
applied and merged after them since the fscrypt patches have been well 
tested.

Ilya, is that okay ?

Thanks

- Xiubo

On 6/6/23 00:54, Matthew Wilcox (Oracle) wrote:
> After we iterate through the locked folios using filemap_get_folios_tag(),
> we currently convert back to a page (and then in some circumstaces back
> to a folio again!).  Just use a folio throughout and avoid various hidden
> calls to compound_head().  Ceph still uses a page array to interact with
> the OSD which should be cleaned up in a subsequent patch.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>   fs/ceph/addr.c | 79 +++++++++++++++++++++++++-------------------------
>   1 file changed, 39 insertions(+), 40 deletions(-)
>
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> index 6bb251a4d613..e2d92a8a53ca 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -888,7 +888,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>   		int num_ops = 0, op_idx;
>   		unsigned i, nr_folios, max_pages, locked_pages = 0;
>   		struct page **pages = NULL, **data_pages;
> -		struct page *page;
> +		struct folio *folio;
>   		pgoff_t strip_unit_end = 0;
>   		u64 offset = 0, len = 0;
>   		bool from_pool = false;
> @@ -902,22 +902,22 @@ static int ceph_writepages_start(struct address_space *mapping,
>   		if (!nr_folios && !locked_pages)
>   			break;
>   		for (i = 0; i < nr_folios && locked_pages < max_pages; i++) {
> -			page = &fbatch.folios[i]->page;
> -			dout("? %p idx %lu\n", page, page->index);
> +			folio = fbatch.folios[i];
> +			dout("? %p idx %lu\n", folio, folio->index);
>   			if (locked_pages == 0)
> -				lock_page(page);  /* first page */
> -			else if (!trylock_page(page))
> +				folio_lock(folio);  /* first folio */
> +			else if (!folio_trylock(folio))
>   				break;
>   
>   			/* only dirty pages, or our accounting breaks */
> -			if (unlikely(!PageDirty(page)) ||
> -			    unlikely(page->mapping != mapping)) {
> -				dout("!dirty or !mapping %p\n", page);
> -				unlock_page(page);
> +			if (unlikely(!folio_test_dirty(folio)) ||
> +			    unlikely(folio->mapping != mapping)) {
> +				dout("!dirty or !mapping %p\n", folio);
> +				folio_unlock(folio);
>   				continue;
>   			}
>   			/* only if matching snap context */
> -			pgsnapc = page_snap_context(page);
> +			pgsnapc = page_snap_context(&folio->page);
>   			if (pgsnapc != snapc) {
>   				dout("page snapc %p %lld != oldest %p %lld\n",
>   				     pgsnapc, pgsnapc->seq, snapc, snapc->seq);
> @@ -925,12 +925,10 @@ static int ceph_writepages_start(struct address_space *mapping,
>   				    !ceph_wbc.head_snapc &&
>   				    wbc->sync_mode != WB_SYNC_NONE)
>   					should_loop = true;
> -				unlock_page(page);
> +				folio_unlock(folio);
>   				continue;
>   			}
> -			if (page_offset(page) >= ceph_wbc.i_size) {
> -				struct folio *folio = page_folio(page);
> -
> +			if (folio_pos(folio) >= ceph_wbc.i_size) {
>   				dout("folio at %lu beyond eof %llu\n",
>   				     folio->index, ceph_wbc.i_size);
>   				if ((ceph_wbc.size_stable ||
> @@ -941,31 +939,32 @@ static int ceph_writepages_start(struct address_space *mapping,
>   				folio_unlock(folio);
>   				continue;
>   			}
> -			if (strip_unit_end && (page->index > strip_unit_end)) {
> -				dout("end of strip unit %p\n", page);
> -				unlock_page(page);
> +			if (strip_unit_end && (folio->index > strip_unit_end)) {
> +				dout("end of strip unit %p\n", folio);
> +				folio_unlock(folio);
>   				break;
>   			}
> -			if (PageWriteback(page) || PageFsCache(page)) {
> +			if (folio_test_writeback(folio) ||
> +			    folio_test_fscache(folio)) {
>   				if (wbc->sync_mode == WB_SYNC_NONE) {
> -					dout("%p under writeback\n", page);
> -					unlock_page(page);
> +					dout("%p under writeback\n", folio);
> +					folio_unlock(folio);
>   					continue;
>   				}
> -				dout("waiting on writeback %p\n", page);
> -				wait_on_page_writeback(page);
> -				wait_on_page_fscache(page);
> +				dout("waiting on writeback %p\n", folio);
> +				folio_wait_writeback(folio);
> +				folio_wait_fscache(folio);
>   			}
>   
> -			if (!clear_page_dirty_for_io(page)) {
> -				dout("%p !clear_page_dirty_for_io\n", page);
> -				unlock_page(page);
> +			if (!folio_clear_dirty_for_io(folio)) {
> +				dout("%p !folio_clear_dirty_for_io\n", folio);
> +				folio_unlock(folio);
>   				continue;
>   			}
>   
>   			/*
>   			 * We have something to write.  If this is
> -			 * the first locked page this time through,
> +			 * the first locked folio this time through,
>   			 * calculate max possinle write size and
>   			 * allocate a page array
>   			 */
> @@ -975,7 +974,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>   				u32 xlen;
>   
>   				/* prepare async write request */
> -				offset = (u64)page_offset(page);
> +				offset = folio_pos(folio);
>   				ceph_calc_file_object_mapping(&ci->i_layout,
>   							      offset, wsize,
>   							      &objnum, &objoff,
> @@ -983,7 +982,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>   				len = xlen;
>   
>   				num_ops = 1;
> -				strip_unit_end = page->index +
> +				strip_unit_end = folio->index +
>   					((len - 1) >> PAGE_SHIFT);
>   
>   				BUG_ON(pages);
> @@ -998,33 +997,33 @@ static int ceph_writepages_start(struct address_space *mapping,
>   				}
>   
>   				len = 0;
> -			} else if (page->index !=
> +			} else if (folio->index !=
>   				   (offset + len) >> PAGE_SHIFT) {
>   				if (num_ops >= (from_pool ?  CEPH_OSD_SLAB_OPS :
>   							     CEPH_OSD_MAX_OPS)) {
> -					redirty_page_for_writepage(wbc, page);
> -					unlock_page(page);
> +					folio_redirty_for_writepage(wbc, folio);
> +					folio_unlock(folio);
>   					break;
>   				}
>   
>   				num_ops++;
> -				offset = (u64)page_offset(page);
> +				offset = (u64)folio_pos(folio);
>   				len = 0;
>   			}
>   
>   			/* note position of first page in fbatch */
> -			dout("%p will write page %p idx %lu\n",
> -			     inode, page, page->index);
> +			dout("%p will write folio %p idx %lu\n",
> +			     inode, folio, folio->index);
>   
>   			if (atomic_long_inc_return(&fsc->writeback_count) >
>   			    CONGESTION_ON_THRESH(
>   				    fsc->mount_options->congestion_kb))
>   				fsc->write_congested = true;
>   
> -			pages[locked_pages++] = page;
> +			pages[locked_pages++] = &folio->page;
>   			fbatch.folios[i] = NULL;
>   
> -			len += thp_size(page);
> +			len += folio_size(folio);
>   		}
>   
>   		/* did we get anything? */
> @@ -1073,7 +1072,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>   			BUG_ON(IS_ERR(req));
>   		}
>   		BUG_ON(len < page_offset(pages[locked_pages - 1]) +
> -			     thp_size(page) - offset);
> +			     folio_size(folio) - offset);
>   
>   		req->r_callback = writepages_finish;
>   		req->r_inode = inode;
> @@ -1115,7 +1114,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>   			set_page_writeback(pages[i]);
>   			if (caching)
>   				ceph_set_page_fscache(pages[i]);
> -			len += thp_size(page);
> +			len += folio_size(folio);
>   		}
>   		ceph_fscache_write_to_cache(inode, offset, len, caching);
>   
> @@ -1125,7 +1124,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>   			/* writepages_finish() clears writeback pages
>   			 * according to the data length, so make sure
>   			 * data length covers all locked pages */
> -			u64 min_len = len + 1 - thp_size(page);
> +			u64 min_len = len + 1 - folio_size(folio);
>   			len = get_writepages_data_length(inode, pages[i - 1],
>   							 offset);
>   			len = max(len, min_len);
Matthew Wilcox June 6, 2023, 6:19 p.m. UTC | #2
On Tue, Jun 06, 2023 at 01:37:46PM +0800, Xiubo Li wrote:
> This Looks good to me.
> 
> BTW, could you rebase this to the 'testing' branch ? This will introduce a

Umm, which testing branch is that?  It applies cleanly to next-20230606
which is generally where I work, since it's a bit unreasonable for me
to keep track of every filesystem development tree.

> lots of conflicts with the fscrypt patches, I'd prefer this could be applied
> and merged after them since the fscrypt patches have been well tested.
> 
> Ilya, is that okay ?
> 
> Thanks
> 
> - Xiubo
> 
> On 6/6/23 00:54, Matthew Wilcox (Oracle) wrote:
> > After we iterate through the locked folios using filemap_get_folios_tag(),
> > we currently convert back to a page (and then in some circumstaces back
> > to a folio again!).  Just use a folio throughout and avoid various hidden
> > calls to compound_head().  Ceph still uses a page array to interact with
> > the OSD which should be cleaned up in a subsequent patch.
> > 
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > ---
> >   fs/ceph/addr.c | 79 +++++++++++++++++++++++++-------------------------
> >   1 file changed, 39 insertions(+), 40 deletions(-)
> > 
> > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> > index 6bb251a4d613..e2d92a8a53ca 100644
> > --- a/fs/ceph/addr.c
> > +++ b/fs/ceph/addr.c
> > @@ -888,7 +888,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   		int num_ops = 0, op_idx;
> >   		unsigned i, nr_folios, max_pages, locked_pages = 0;
> >   		struct page **pages = NULL, **data_pages;
> > -		struct page *page;
> > +		struct folio *folio;
> >   		pgoff_t strip_unit_end = 0;
> >   		u64 offset = 0, len = 0;
> >   		bool from_pool = false;
> > @@ -902,22 +902,22 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   		if (!nr_folios && !locked_pages)
> >   			break;
> >   		for (i = 0; i < nr_folios && locked_pages < max_pages; i++) {
> > -			page = &fbatch.folios[i]->page;
> > -			dout("? %p idx %lu\n", page, page->index);
> > +			folio = fbatch.folios[i];
> > +			dout("? %p idx %lu\n", folio, folio->index);
> >   			if (locked_pages == 0)
> > -				lock_page(page);  /* first page */
> > -			else if (!trylock_page(page))
> > +				folio_lock(folio);  /* first folio */
> > +			else if (!folio_trylock(folio))
> >   				break;
> >   			/* only dirty pages, or our accounting breaks */
> > -			if (unlikely(!PageDirty(page)) ||
> > -			    unlikely(page->mapping != mapping)) {
> > -				dout("!dirty or !mapping %p\n", page);
> > -				unlock_page(page);
> > +			if (unlikely(!folio_test_dirty(folio)) ||
> > +			    unlikely(folio->mapping != mapping)) {
> > +				dout("!dirty or !mapping %p\n", folio);
> > +				folio_unlock(folio);
> >   				continue;
> >   			}
> >   			/* only if matching snap context */
> > -			pgsnapc = page_snap_context(page);
> > +			pgsnapc = page_snap_context(&folio->page);
> >   			if (pgsnapc != snapc) {
> >   				dout("page snapc %p %lld != oldest %p %lld\n",
> >   				     pgsnapc, pgsnapc->seq, snapc, snapc->seq);
> > @@ -925,12 +925,10 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   				    !ceph_wbc.head_snapc &&
> >   				    wbc->sync_mode != WB_SYNC_NONE)
> >   					should_loop = true;
> > -				unlock_page(page);
> > +				folio_unlock(folio);
> >   				continue;
> >   			}
> > -			if (page_offset(page) >= ceph_wbc.i_size) {
> > -				struct folio *folio = page_folio(page);
> > -
> > +			if (folio_pos(folio) >= ceph_wbc.i_size) {
> >   				dout("folio at %lu beyond eof %llu\n",
> >   				     folio->index, ceph_wbc.i_size);
> >   				if ((ceph_wbc.size_stable ||
> > @@ -941,31 +939,32 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   				folio_unlock(folio);
> >   				continue;
> >   			}
> > -			if (strip_unit_end && (page->index > strip_unit_end)) {
> > -				dout("end of strip unit %p\n", page);
> > -				unlock_page(page);
> > +			if (strip_unit_end && (folio->index > strip_unit_end)) {
> > +				dout("end of strip unit %p\n", folio);
> > +				folio_unlock(folio);
> >   				break;
> >   			}
> > -			if (PageWriteback(page) || PageFsCache(page)) {
> > +			if (folio_test_writeback(folio) ||
> > +			    folio_test_fscache(folio)) {
> >   				if (wbc->sync_mode == WB_SYNC_NONE) {
> > -					dout("%p under writeback\n", page);
> > -					unlock_page(page);
> > +					dout("%p under writeback\n", folio);
> > +					folio_unlock(folio);
> >   					continue;
> >   				}
> > -				dout("waiting on writeback %p\n", page);
> > -				wait_on_page_writeback(page);
> > -				wait_on_page_fscache(page);
> > +				dout("waiting on writeback %p\n", folio);
> > +				folio_wait_writeback(folio);
> > +				folio_wait_fscache(folio);
> >   			}
> > -			if (!clear_page_dirty_for_io(page)) {
> > -				dout("%p !clear_page_dirty_for_io\n", page);
> > -				unlock_page(page);
> > +			if (!folio_clear_dirty_for_io(folio)) {
> > +				dout("%p !folio_clear_dirty_for_io\n", folio);
> > +				folio_unlock(folio);
> >   				continue;
> >   			}
> >   			/*
> >   			 * We have something to write.  If this is
> > -			 * the first locked page this time through,
> > +			 * the first locked folio this time through,
> >   			 * calculate max possinle write size and
> >   			 * allocate a page array
> >   			 */
> > @@ -975,7 +974,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   				u32 xlen;
> >   				/* prepare async write request */
> > -				offset = (u64)page_offset(page);
> > +				offset = folio_pos(folio);
> >   				ceph_calc_file_object_mapping(&ci->i_layout,
> >   							      offset, wsize,
> >   							      &objnum, &objoff,
> > @@ -983,7 +982,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   				len = xlen;
> >   				num_ops = 1;
> > -				strip_unit_end = page->index +
> > +				strip_unit_end = folio->index +
> >   					((len - 1) >> PAGE_SHIFT);
> >   				BUG_ON(pages);
> > @@ -998,33 +997,33 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   				}
> >   				len = 0;
> > -			} else if (page->index !=
> > +			} else if (folio->index !=
> >   				   (offset + len) >> PAGE_SHIFT) {
> >   				if (num_ops >= (from_pool ?  CEPH_OSD_SLAB_OPS :
> >   							     CEPH_OSD_MAX_OPS)) {
> > -					redirty_page_for_writepage(wbc, page);
> > -					unlock_page(page);
> > +					folio_redirty_for_writepage(wbc, folio);
> > +					folio_unlock(folio);
> >   					break;
> >   				}
> >   				num_ops++;
> > -				offset = (u64)page_offset(page);
> > +				offset = (u64)folio_pos(folio);
> >   				len = 0;
> >   			}
> >   			/* note position of first page in fbatch */
> > -			dout("%p will write page %p idx %lu\n",
> > -			     inode, page, page->index);
> > +			dout("%p will write folio %p idx %lu\n",
> > +			     inode, folio, folio->index);
> >   			if (atomic_long_inc_return(&fsc->writeback_count) >
> >   			    CONGESTION_ON_THRESH(
> >   				    fsc->mount_options->congestion_kb))
> >   				fsc->write_congested = true;
> > -			pages[locked_pages++] = page;
> > +			pages[locked_pages++] = &folio->page;
> >   			fbatch.folios[i] = NULL;
> > -			len += thp_size(page);
> > +			len += folio_size(folio);
> >   		}
> >   		/* did we get anything? */
> > @@ -1073,7 +1072,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   			BUG_ON(IS_ERR(req));
> >   		}
> >   		BUG_ON(len < page_offset(pages[locked_pages - 1]) +
> > -			     thp_size(page) - offset);
> > +			     folio_size(folio) - offset);
> >   		req->r_callback = writepages_finish;
> >   		req->r_inode = inode;
> > @@ -1115,7 +1114,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   			set_page_writeback(pages[i]);
> >   			if (caching)
> >   				ceph_set_page_fscache(pages[i]);
> > -			len += thp_size(page);
> > +			len += folio_size(folio);
> >   		}
> >   		ceph_fscache_write_to_cache(inode, offset, len, caching);
> > @@ -1125,7 +1124,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> >   			/* writepages_finish() clears writeback pages
> >   			 * according to the data length, so make sure
> >   			 * data length covers all locked pages */
> > -			u64 min_len = len + 1 - thp_size(page);
> > +			u64 min_len = len + 1 - folio_size(folio);
> >   			len = get_writepages_data_length(inode, pages[i - 1],
> >   							 offset);
> >   			len = max(len, min_len);
>
Xiubo Li June 7, 2023, 12:31 a.m. UTC | #3
On 6/7/23 02:19, Matthew Wilcox wrote:
> On Tue, Jun 06, 2023 at 01:37:46PM +0800, Xiubo Li wrote:
>> This Looks good to me.
>>
>> BTW, could you rebase this to the 'testing' branch ? This will introduce a
> Umm, which testing branch is that?  It applies cleanly to next-20230606
> which is generally where I work, since it's a bit unreasonable for me
> to keep track of every filesystem development tree.

Here https://github.com/ceph/ceph-client/commits/testing.

Thanks

- Xiubo

>> lots of conflicts with the fscrypt patches, I'd prefer this could be applied
>> and merged after them since the fscrypt patches have been well tested.
>>
>> Ilya, is that okay ?
>>
>> Thanks
>>
>> - Xiubo
>>
>> On 6/6/23 00:54, Matthew Wilcox (Oracle) wrote:
>>> After we iterate through the locked folios using filemap_get_folios_tag(),
>>> we currently convert back to a page (and then in some circumstaces back
>>> to a folio again!).  Just use a folio throughout and avoid various hidden
>>> calls to compound_head().  Ceph still uses a page array to interact with
>>> the OSD which should be cleaned up in a subsequent patch.
>>>
>>> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>>> ---
>>>    fs/ceph/addr.c | 79 +++++++++++++++++++++++++-------------------------
>>>    1 file changed, 39 insertions(+), 40 deletions(-)
>>>
>>> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
>>> index 6bb251a4d613..e2d92a8a53ca 100644
>>> --- a/fs/ceph/addr.c
>>> +++ b/fs/ceph/addr.c
>>> @@ -888,7 +888,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    		int num_ops = 0, op_idx;
>>>    		unsigned i, nr_folios, max_pages, locked_pages = 0;
>>>    		struct page **pages = NULL, **data_pages;
>>> -		struct page *page;
>>> +		struct folio *folio;
>>>    		pgoff_t strip_unit_end = 0;
>>>    		u64 offset = 0, len = 0;
>>>    		bool from_pool = false;
>>> @@ -902,22 +902,22 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    		if (!nr_folios && !locked_pages)
>>>    			break;
>>>    		for (i = 0; i < nr_folios && locked_pages < max_pages; i++) {
>>> -			page = &fbatch.folios[i]->page;
>>> -			dout("? %p idx %lu\n", page, page->index);
>>> +			folio = fbatch.folios[i];
>>> +			dout("? %p idx %lu\n", folio, folio->index);
>>>    			if (locked_pages == 0)
>>> -				lock_page(page);  /* first page */
>>> -			else if (!trylock_page(page))
>>> +				folio_lock(folio);  /* first folio */
>>> +			else if (!folio_trylock(folio))
>>>    				break;
>>>    			/* only dirty pages, or our accounting breaks */
>>> -			if (unlikely(!PageDirty(page)) ||
>>> -			    unlikely(page->mapping != mapping)) {
>>> -				dout("!dirty or !mapping %p\n", page);
>>> -				unlock_page(page);
>>> +			if (unlikely(!folio_test_dirty(folio)) ||
>>> +			    unlikely(folio->mapping != mapping)) {
>>> +				dout("!dirty or !mapping %p\n", folio);
>>> +				folio_unlock(folio);
>>>    				continue;
>>>    			}
>>>    			/* only if matching snap context */
>>> -			pgsnapc = page_snap_context(page);
>>> +			pgsnapc = page_snap_context(&folio->page);
>>>    			if (pgsnapc != snapc) {
>>>    				dout("page snapc %p %lld != oldest %p %lld\n",
>>>    				     pgsnapc, pgsnapc->seq, snapc, snapc->seq);
>>> @@ -925,12 +925,10 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    				    !ceph_wbc.head_snapc &&
>>>    				    wbc->sync_mode != WB_SYNC_NONE)
>>>    					should_loop = true;
>>> -				unlock_page(page);
>>> +				folio_unlock(folio);
>>>    				continue;
>>>    			}
>>> -			if (page_offset(page) >= ceph_wbc.i_size) {
>>> -				struct folio *folio = page_folio(page);
>>> -
>>> +			if (folio_pos(folio) >= ceph_wbc.i_size) {
>>>    				dout("folio at %lu beyond eof %llu\n",
>>>    				     folio->index, ceph_wbc.i_size);
>>>    				if ((ceph_wbc.size_stable ||
>>> @@ -941,31 +939,32 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    				folio_unlock(folio);
>>>    				continue;
>>>    			}
>>> -			if (strip_unit_end && (page->index > strip_unit_end)) {
>>> -				dout("end of strip unit %p\n", page);
>>> -				unlock_page(page);
>>> +			if (strip_unit_end && (folio->index > strip_unit_end)) {
>>> +				dout("end of strip unit %p\n", folio);
>>> +				folio_unlock(folio);
>>>    				break;
>>>    			}
>>> -			if (PageWriteback(page) || PageFsCache(page)) {
>>> +			if (folio_test_writeback(folio) ||
>>> +			    folio_test_fscache(folio)) {
>>>    				if (wbc->sync_mode == WB_SYNC_NONE) {
>>> -					dout("%p under writeback\n", page);
>>> -					unlock_page(page);
>>> +					dout("%p under writeback\n", folio);
>>> +					folio_unlock(folio);
>>>    					continue;
>>>    				}
>>> -				dout("waiting on writeback %p\n", page);
>>> -				wait_on_page_writeback(page);
>>> -				wait_on_page_fscache(page);
>>> +				dout("waiting on writeback %p\n", folio);
>>> +				folio_wait_writeback(folio);
>>> +				folio_wait_fscache(folio);
>>>    			}
>>> -			if (!clear_page_dirty_for_io(page)) {
>>> -				dout("%p !clear_page_dirty_for_io\n", page);
>>> -				unlock_page(page);
>>> +			if (!folio_clear_dirty_for_io(folio)) {
>>> +				dout("%p !folio_clear_dirty_for_io\n", folio);
>>> +				folio_unlock(folio);
>>>    				continue;
>>>    			}
>>>    			/*
>>>    			 * We have something to write.  If this is
>>> -			 * the first locked page this time through,
>>> +			 * the first locked folio this time through,
>>>    			 * calculate max possinle write size and
>>>    			 * allocate a page array
>>>    			 */
>>> @@ -975,7 +974,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    				u32 xlen;
>>>    				/* prepare async write request */
>>> -				offset = (u64)page_offset(page);
>>> +				offset = folio_pos(folio);
>>>    				ceph_calc_file_object_mapping(&ci->i_layout,
>>>    							      offset, wsize,
>>>    							      &objnum, &objoff,
>>> @@ -983,7 +982,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    				len = xlen;
>>>    				num_ops = 1;
>>> -				strip_unit_end = page->index +
>>> +				strip_unit_end = folio->index +
>>>    					((len - 1) >> PAGE_SHIFT);
>>>    				BUG_ON(pages);
>>> @@ -998,33 +997,33 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    				}
>>>    				len = 0;
>>> -			} else if (page->index !=
>>> +			} else if (folio->index !=
>>>    				   (offset + len) >> PAGE_SHIFT) {
>>>    				if (num_ops >= (from_pool ?  CEPH_OSD_SLAB_OPS :
>>>    							     CEPH_OSD_MAX_OPS)) {
>>> -					redirty_page_for_writepage(wbc, page);
>>> -					unlock_page(page);
>>> +					folio_redirty_for_writepage(wbc, folio);
>>> +					folio_unlock(folio);
>>>    					break;
>>>    				}
>>>    				num_ops++;
>>> -				offset = (u64)page_offset(page);
>>> +				offset = (u64)folio_pos(folio);
>>>    				len = 0;
>>>    			}
>>>    			/* note position of first page in fbatch */
>>> -			dout("%p will write page %p idx %lu\n",
>>> -			     inode, page, page->index);
>>> +			dout("%p will write folio %p idx %lu\n",
>>> +			     inode, folio, folio->index);
>>>    			if (atomic_long_inc_return(&fsc->writeback_count) >
>>>    			    CONGESTION_ON_THRESH(
>>>    				    fsc->mount_options->congestion_kb))
>>>    				fsc->write_congested = true;
>>> -			pages[locked_pages++] = page;
>>> +			pages[locked_pages++] = &folio->page;
>>>    			fbatch.folios[i] = NULL;
>>> -			len += thp_size(page);
>>> +			len += folio_size(folio);
>>>    		}
>>>    		/* did we get anything? */
>>> @@ -1073,7 +1072,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    			BUG_ON(IS_ERR(req));
>>>    		}
>>>    		BUG_ON(len < page_offset(pages[locked_pages - 1]) +
>>> -			     thp_size(page) - offset);
>>> +			     folio_size(folio) - offset);
>>>    		req->r_callback = writepages_finish;
>>>    		req->r_inode = inode;
>>> @@ -1115,7 +1114,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    			set_page_writeback(pages[i]);
>>>    			if (caching)
>>>    				ceph_set_page_fscache(pages[i]);
>>> -			len += thp_size(page);
>>> +			len += folio_size(folio);
>>>    		}
>>>    		ceph_fscache_write_to_cache(inode, offset, len, caching);
>>> @@ -1125,7 +1124,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>>>    			/* writepages_finish() clears writeback pages
>>>    			 * according to the data length, so make sure
>>>    			 * data length covers all locked pages */
>>> -			u64 min_len = len + 1 - thp_size(page);
>>> +			u64 min_len = len + 1 - folio_size(folio);
>>>    			len = get_writepages_data_length(inode, pages[i - 1],
>>>    							 offset);
>>>    			len = max(len, min_len);
Matthew Wilcox June 20, 2023, 3:42 a.m. UTC | #4
On Wed, Jun 07, 2023 at 08:31:46AM +0800, Xiubo Li wrote:
> 
> On 6/7/23 02:19, Matthew Wilcox wrote:
> > On Tue, Jun 06, 2023 at 01:37:46PM +0800, Xiubo Li wrote:
> > > This Looks good to me.
> > > 
> > > BTW, could you rebase this to the 'testing' branch ? This will introduce a
> > Umm, which testing branch is that?  It applies cleanly to next-20230606
> > which is generally where I work, since it's a bit unreasonable for me
> > to keep track of every filesystem development tree.
> 
> Here https://github.com/ceph/ceph-client/commits/testing.

Are the fscrypt patches planned for 6.5?  Because they really should
have been in -next a few weeks ago if they are.

> Thanks
> 
> - Xiubo
> 
> > > lots of conflicts with the fscrypt patches, I'd prefer this could be applied
> > > and merged after them since the fscrypt patches have been well tested.
> > > 
> > > Ilya, is that okay ?
> > > 
> > > Thanks
> > > 
> > > - Xiubo
> > > 
> > > On 6/6/23 00:54, Matthew Wilcox (Oracle) wrote:
> > > > After we iterate through the locked folios using filemap_get_folios_tag(),
> > > > we currently convert back to a page (and then in some circumstaces back
> > > > to a folio again!).  Just use a folio throughout and avoid various hidden
> > > > calls to compound_head().  Ceph still uses a page array to interact with
> > > > the OSD which should be cleaned up in a subsequent patch.
> > > > 
> > > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > > > ---
> > > >    fs/ceph/addr.c | 79 +++++++++++++++++++++++++-------------------------
> > > >    1 file changed, 39 insertions(+), 40 deletions(-)
> > > > 
> > > > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> > > > index 6bb251a4d613..e2d92a8a53ca 100644
> > > > --- a/fs/ceph/addr.c
> > > > +++ b/fs/ceph/addr.c
> > > > @@ -888,7 +888,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    		int num_ops = 0, op_idx;
> > > >    		unsigned i, nr_folios, max_pages, locked_pages = 0;
> > > >    		struct page **pages = NULL, **data_pages;
> > > > -		struct page *page;
> > > > +		struct folio *folio;
> > > >    		pgoff_t strip_unit_end = 0;
> > > >    		u64 offset = 0, len = 0;
> > > >    		bool from_pool = false;
> > > > @@ -902,22 +902,22 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    		if (!nr_folios && !locked_pages)
> > > >    			break;
> > > >    		for (i = 0; i < nr_folios && locked_pages < max_pages; i++) {
> > > > -			page = &fbatch.folios[i]->page;
> > > > -			dout("? %p idx %lu\n", page, page->index);
> > > > +			folio = fbatch.folios[i];
> > > > +			dout("? %p idx %lu\n", folio, folio->index);
> > > >    			if (locked_pages == 0)
> > > > -				lock_page(page);  /* first page */
> > > > -			else if (!trylock_page(page))
> > > > +				folio_lock(folio);  /* first folio */
> > > > +			else if (!folio_trylock(folio))
> > > >    				break;
> > > >    			/* only dirty pages, or our accounting breaks */
> > > > -			if (unlikely(!PageDirty(page)) ||
> > > > -			    unlikely(page->mapping != mapping)) {
> > > > -				dout("!dirty or !mapping %p\n", page);
> > > > -				unlock_page(page);
> > > > +			if (unlikely(!folio_test_dirty(folio)) ||
> > > > +			    unlikely(folio->mapping != mapping)) {
> > > > +				dout("!dirty or !mapping %p\n", folio);
> > > > +				folio_unlock(folio);
> > > >    				continue;
> > > >    			}
> > > >    			/* only if matching snap context */
> > > > -			pgsnapc = page_snap_context(page);
> > > > +			pgsnapc = page_snap_context(&folio->page);
> > > >    			if (pgsnapc != snapc) {
> > > >    				dout("page snapc %p %lld != oldest %p %lld\n",
> > > >    				     pgsnapc, pgsnapc->seq, snapc, snapc->seq);
> > > > @@ -925,12 +925,10 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    				    !ceph_wbc.head_snapc &&
> > > >    				    wbc->sync_mode != WB_SYNC_NONE)
> > > >    					should_loop = true;
> > > > -				unlock_page(page);
> > > > +				folio_unlock(folio);
> > > >    				continue;
> > > >    			}
> > > > -			if (page_offset(page) >= ceph_wbc.i_size) {
> > > > -				struct folio *folio = page_folio(page);
> > > > -
> > > > +			if (folio_pos(folio) >= ceph_wbc.i_size) {
> > > >    				dout("folio at %lu beyond eof %llu\n",
> > > >    				     folio->index, ceph_wbc.i_size);
> > > >    				if ((ceph_wbc.size_stable ||
> > > > @@ -941,31 +939,32 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    				folio_unlock(folio);
> > > >    				continue;
> > > >    			}
> > > > -			if (strip_unit_end && (page->index > strip_unit_end)) {
> > > > -				dout("end of strip unit %p\n", page);
> > > > -				unlock_page(page);
> > > > +			if (strip_unit_end && (folio->index > strip_unit_end)) {
> > > > +				dout("end of strip unit %p\n", folio);
> > > > +				folio_unlock(folio);
> > > >    				break;
> > > >    			}
> > > > -			if (PageWriteback(page) || PageFsCache(page)) {
> > > > +			if (folio_test_writeback(folio) ||
> > > > +			    folio_test_fscache(folio)) {
> > > >    				if (wbc->sync_mode == WB_SYNC_NONE) {
> > > > -					dout("%p under writeback\n", page);
> > > > -					unlock_page(page);
> > > > +					dout("%p under writeback\n", folio);
> > > > +					folio_unlock(folio);
> > > >    					continue;
> > > >    				}
> > > > -				dout("waiting on writeback %p\n", page);
> > > > -				wait_on_page_writeback(page);
> > > > -				wait_on_page_fscache(page);
> > > > +				dout("waiting on writeback %p\n", folio);
> > > > +				folio_wait_writeback(folio);
> > > > +				folio_wait_fscache(folio);
> > > >    			}
> > > > -			if (!clear_page_dirty_for_io(page)) {
> > > > -				dout("%p !clear_page_dirty_for_io\n", page);
> > > > -				unlock_page(page);
> > > > +			if (!folio_clear_dirty_for_io(folio)) {
> > > > +				dout("%p !folio_clear_dirty_for_io\n", folio);
> > > > +				folio_unlock(folio);
> > > >    				continue;
> > > >    			}
> > > >    			/*
> > > >    			 * We have something to write.  If this is
> > > > -			 * the first locked page this time through,
> > > > +			 * the first locked folio this time through,
> > > >    			 * calculate max possinle write size and
> > > >    			 * allocate a page array
> > > >    			 */
> > > > @@ -975,7 +974,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    				u32 xlen;
> > > >    				/* prepare async write request */
> > > > -				offset = (u64)page_offset(page);
> > > > +				offset = folio_pos(folio);
> > > >    				ceph_calc_file_object_mapping(&ci->i_layout,
> > > >    							      offset, wsize,
> > > >    							      &objnum, &objoff,
> > > > @@ -983,7 +982,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    				len = xlen;
> > > >    				num_ops = 1;
> > > > -				strip_unit_end = page->index +
> > > > +				strip_unit_end = folio->index +
> > > >    					((len - 1) >> PAGE_SHIFT);
> > > >    				BUG_ON(pages);
> > > > @@ -998,33 +997,33 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    				}
> > > >    				len = 0;
> > > > -			} else if (page->index !=
> > > > +			} else if (folio->index !=
> > > >    				   (offset + len) >> PAGE_SHIFT) {
> > > >    				if (num_ops >= (from_pool ?  CEPH_OSD_SLAB_OPS :
> > > >    							     CEPH_OSD_MAX_OPS)) {
> > > > -					redirty_page_for_writepage(wbc, page);
> > > > -					unlock_page(page);
> > > > +					folio_redirty_for_writepage(wbc, folio);
> > > > +					folio_unlock(folio);
> > > >    					break;
> > > >    				}
> > > >    				num_ops++;
> > > > -				offset = (u64)page_offset(page);
> > > > +				offset = (u64)folio_pos(folio);
> > > >    				len = 0;
> > > >    			}
> > > >    			/* note position of first page in fbatch */
> > > > -			dout("%p will write page %p idx %lu\n",
> > > > -			     inode, page, page->index);
> > > > +			dout("%p will write folio %p idx %lu\n",
> > > > +			     inode, folio, folio->index);
> > > >    			if (atomic_long_inc_return(&fsc->writeback_count) >
> > > >    			    CONGESTION_ON_THRESH(
> > > >    				    fsc->mount_options->congestion_kb))
> > > >    				fsc->write_congested = true;
> > > > -			pages[locked_pages++] = page;
> > > > +			pages[locked_pages++] = &folio->page;
> > > >    			fbatch.folios[i] = NULL;
> > > > -			len += thp_size(page);
> > > > +			len += folio_size(folio);
> > > >    		}
> > > >    		/* did we get anything? */
> > > > @@ -1073,7 +1072,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    			BUG_ON(IS_ERR(req));
> > > >    		}
> > > >    		BUG_ON(len < page_offset(pages[locked_pages - 1]) +
> > > > -			     thp_size(page) - offset);
> > > > +			     folio_size(folio) - offset);
> > > >    		req->r_callback = writepages_finish;
> > > >    		req->r_inode = inode;
> > > > @@ -1115,7 +1114,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    			set_page_writeback(pages[i]);
> > > >    			if (caching)
> > > >    				ceph_set_page_fscache(pages[i]);
> > > > -			len += thp_size(page);
> > > > +			len += folio_size(folio);
> > > >    		}
> > > >    		ceph_fscache_write_to_cache(inode, offset, len, caching);
> > > > @@ -1125,7 +1124,7 @@ static int ceph_writepages_start(struct address_space *mapping,
> > > >    			/* writepages_finish() clears writeback pages
> > > >    			 * according to the data length, so make sure
> > > >    			 * data length covers all locked pages */
> > > > -			u64 min_len = len + 1 - thp_size(page);
> > > > +			u64 min_len = len + 1 - folio_size(folio);
> > > >    			len = get_writepages_data_length(inode, pages[i - 1],
> > > >    							 offset);
> > > >    			len = max(len, min_len);
>
Ilya Dryomov June 24, 2023, 7:41 a.m. UTC | #5
On Tue, Jun 20, 2023 at 5:42 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Wed, Jun 07, 2023 at 08:31:46AM +0800, Xiubo Li wrote:
> >
> > On 6/7/23 02:19, Matthew Wilcox wrote:
> > > On Tue, Jun 06, 2023 at 01:37:46PM +0800, Xiubo Li wrote:
> > > > This Looks good to me.
> > > >
> > > > BTW, could you rebase this to the 'testing' branch ? This will introduce a
> > > Umm, which testing branch is that?  It applies cleanly to next-20230606
> > > which is generally where I work, since it's a bit unreasonable for me
> > > to keep track of every filesystem development tree.
> >
> > Here https://github.com/ceph/ceph-client/commits/testing.
>
> Are the fscrypt patches planned for 6.5?  Because they really should
> have been in -next a few weeks ago if they are.

Hi Matthew,

No, they are currently targeted for 6.6.

Thanks,

                Ilya
diff mbox series

Patch

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 6bb251a4d613..e2d92a8a53ca 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -888,7 +888,7 @@  static int ceph_writepages_start(struct address_space *mapping,
 		int num_ops = 0, op_idx;
 		unsigned i, nr_folios, max_pages, locked_pages = 0;
 		struct page **pages = NULL, **data_pages;
-		struct page *page;
+		struct folio *folio;
 		pgoff_t strip_unit_end = 0;
 		u64 offset = 0, len = 0;
 		bool from_pool = false;
@@ -902,22 +902,22 @@  static int ceph_writepages_start(struct address_space *mapping,
 		if (!nr_folios && !locked_pages)
 			break;
 		for (i = 0; i < nr_folios && locked_pages < max_pages; i++) {
-			page = &fbatch.folios[i]->page;
-			dout("? %p idx %lu\n", page, page->index);
+			folio = fbatch.folios[i];
+			dout("? %p idx %lu\n", folio, folio->index);
 			if (locked_pages == 0)
-				lock_page(page);  /* first page */
-			else if (!trylock_page(page))
+				folio_lock(folio);  /* first folio */
+			else if (!folio_trylock(folio))
 				break;
 
 			/* only dirty pages, or our accounting breaks */
-			if (unlikely(!PageDirty(page)) ||
-			    unlikely(page->mapping != mapping)) {
-				dout("!dirty or !mapping %p\n", page);
-				unlock_page(page);
+			if (unlikely(!folio_test_dirty(folio)) ||
+			    unlikely(folio->mapping != mapping)) {
+				dout("!dirty or !mapping %p\n", folio);
+				folio_unlock(folio);
 				continue;
 			}
 			/* only if matching snap context */
-			pgsnapc = page_snap_context(page);
+			pgsnapc = page_snap_context(&folio->page);
 			if (pgsnapc != snapc) {
 				dout("page snapc %p %lld != oldest %p %lld\n",
 				     pgsnapc, pgsnapc->seq, snapc, snapc->seq);
@@ -925,12 +925,10 @@  static int ceph_writepages_start(struct address_space *mapping,
 				    !ceph_wbc.head_snapc &&
 				    wbc->sync_mode != WB_SYNC_NONE)
 					should_loop = true;
-				unlock_page(page);
+				folio_unlock(folio);
 				continue;
 			}
-			if (page_offset(page) >= ceph_wbc.i_size) {
-				struct folio *folio = page_folio(page);
-
+			if (folio_pos(folio) >= ceph_wbc.i_size) {
 				dout("folio at %lu beyond eof %llu\n",
 				     folio->index, ceph_wbc.i_size);
 				if ((ceph_wbc.size_stable ||
@@ -941,31 +939,32 @@  static int ceph_writepages_start(struct address_space *mapping,
 				folio_unlock(folio);
 				continue;
 			}
-			if (strip_unit_end && (page->index > strip_unit_end)) {
-				dout("end of strip unit %p\n", page);
-				unlock_page(page);
+			if (strip_unit_end && (folio->index > strip_unit_end)) {
+				dout("end of strip unit %p\n", folio);
+				folio_unlock(folio);
 				break;
 			}
-			if (PageWriteback(page) || PageFsCache(page)) {
+			if (folio_test_writeback(folio) ||
+			    folio_test_fscache(folio)) {
 				if (wbc->sync_mode == WB_SYNC_NONE) {
-					dout("%p under writeback\n", page);
-					unlock_page(page);
+					dout("%p under writeback\n", folio);
+					folio_unlock(folio);
 					continue;
 				}
-				dout("waiting on writeback %p\n", page);
-				wait_on_page_writeback(page);
-				wait_on_page_fscache(page);
+				dout("waiting on writeback %p\n", folio);
+				folio_wait_writeback(folio);
+				folio_wait_fscache(folio);
 			}
 
-			if (!clear_page_dirty_for_io(page)) {
-				dout("%p !clear_page_dirty_for_io\n", page);
-				unlock_page(page);
+			if (!folio_clear_dirty_for_io(folio)) {
+				dout("%p !folio_clear_dirty_for_io\n", folio);
+				folio_unlock(folio);
 				continue;
 			}
 
 			/*
 			 * We have something to write.  If this is
-			 * the first locked page this time through,
+			 * the first locked folio this time through,
 			 * calculate max possinle write size and
 			 * allocate a page array
 			 */
@@ -975,7 +974,7 @@  static int ceph_writepages_start(struct address_space *mapping,
 				u32 xlen;
 
 				/* prepare async write request */
-				offset = (u64)page_offset(page);
+				offset = folio_pos(folio);
 				ceph_calc_file_object_mapping(&ci->i_layout,
 							      offset, wsize,
 							      &objnum, &objoff,
@@ -983,7 +982,7 @@  static int ceph_writepages_start(struct address_space *mapping,
 				len = xlen;
 
 				num_ops = 1;
-				strip_unit_end = page->index +
+				strip_unit_end = folio->index +
 					((len - 1) >> PAGE_SHIFT);
 
 				BUG_ON(pages);
@@ -998,33 +997,33 @@  static int ceph_writepages_start(struct address_space *mapping,
 				}
 
 				len = 0;
-			} else if (page->index !=
+			} else if (folio->index !=
 				   (offset + len) >> PAGE_SHIFT) {
 				if (num_ops >= (from_pool ?  CEPH_OSD_SLAB_OPS :
 							     CEPH_OSD_MAX_OPS)) {
-					redirty_page_for_writepage(wbc, page);
-					unlock_page(page);
+					folio_redirty_for_writepage(wbc, folio);
+					folio_unlock(folio);
 					break;
 				}
 
 				num_ops++;
-				offset = (u64)page_offset(page);
+				offset = (u64)folio_pos(folio);
 				len = 0;
 			}
 
 			/* note position of first page in fbatch */
-			dout("%p will write page %p idx %lu\n",
-			     inode, page, page->index);
+			dout("%p will write folio %p idx %lu\n",
+			     inode, folio, folio->index);
 
 			if (atomic_long_inc_return(&fsc->writeback_count) >
 			    CONGESTION_ON_THRESH(
 				    fsc->mount_options->congestion_kb))
 				fsc->write_congested = true;
 
-			pages[locked_pages++] = page;
+			pages[locked_pages++] = &folio->page;
 			fbatch.folios[i] = NULL;
 
-			len += thp_size(page);
+			len += folio_size(folio);
 		}
 
 		/* did we get anything? */
@@ -1073,7 +1072,7 @@  static int ceph_writepages_start(struct address_space *mapping,
 			BUG_ON(IS_ERR(req));
 		}
 		BUG_ON(len < page_offset(pages[locked_pages - 1]) +
-			     thp_size(page) - offset);
+			     folio_size(folio) - offset);
 
 		req->r_callback = writepages_finish;
 		req->r_inode = inode;
@@ -1115,7 +1114,7 @@  static int ceph_writepages_start(struct address_space *mapping,
 			set_page_writeback(pages[i]);
 			if (caching)
 				ceph_set_page_fscache(pages[i]);
-			len += thp_size(page);
+			len += folio_size(folio);
 		}
 		ceph_fscache_write_to_cache(inode, offset, len, caching);
 
@@ -1125,7 +1124,7 @@  static int ceph_writepages_start(struct address_space *mapping,
 			/* writepages_finish() clears writeback pages
 			 * according to the data length, so make sure
 			 * data length covers all locked pages */
-			u64 min_len = len + 1 - thp_size(page);
+			u64 min_len = len + 1 - folio_size(folio);
 			len = get_writepages_data_length(inode, pages[i - 1],
 							 offset);
 			len = max(len, min_len);