[PATCH 0/2] fuse: convert the readdir cache to use folios

[PATCH 0/2] fuse: convert the readdir cache to use folios

[Tal Zussman]

Convert the readdir cache lookups in fs/fuse/readdir.c to folios. This
removes the last caller of find_get_page_flags() and one of the last
callers of find_lock_page().

Based on fuse/for-next.

---
Tal Zussman (2):
      fuse: convert fuse_add_dirent_to_cache() to use folios
      fuse: convert fuse_readdir_cached() to use folios

 fs/fuse/readdir.c | 70 ++++++++++++++++++++++++++++---------------------------
 1 file changed, 36 insertions(+), 34 deletions(-)
---
base-commit: 10bd6b32965265688fa277d166ab224de8e86eb2
change-id: 20260906-fuse-readdir-folio-009ae33a7854

Best regards,
--  
Tal Zussman <tz2294@columbia.edu>

[PATCH 1/2] fuse: convert fuse_add_dirent_to_cache() to use folios

[Tal Zussman]

Replace find_lock_page() and find_or_create_page() with
filemap_lock_folio() and filemap_grab_folio(), and switch the remaining
page helpers to their folio equivalents.

Each index of the readdir cache holds one page of dirents. fuse does not
enable large folios, so these folios are always a single page.

Also write the dirent with folio_fill_tail() and memcpy_to_folio()
instead of open-coding it.

This removes two hidden calls to compound_head() and one of the last
callers of find_lock_page().

Signed-off-by: Tal Zussman <tz2294@columbia.edu>
---
 fs/fuse/readdir.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c
index 5ca87151d70d..e6b828eb41a5 100644
--- a/fs/fuse/readdir.c
+++ b/fs/fuse/readdir.c
@@ -34,11 +34,11 @@ static void fuse_add_dirent_to_cache(struct file *file,
 	struct fuse_inode *fi = get_fuse_inode(file_inode(file));
 	size_t reclen = FUSE_DIRENT_SIZE(dirent);
 	pgoff_t index;
-	struct page *page;
+	struct folio *folio;
 	loff_t size;
 	u64 version;
 	unsigned int offset;
-	void *addr;
+	size_t folio_offset;
 
 	/* Dirent doesn't fit in readdir cache page?  Skip caching. */
 	if (reclen > PAGE_SIZE)
@@ -64,13 +64,11 @@ static void fuse_add_dirent_to_cache(struct file *file,
 	}
 	spin_unlock(&fi->rdc.lock);
 
-	if (offset) {
-		page = find_lock_page(file->f_mapping, index);
-	} else {
-		page = find_or_create_page(file->f_mapping, index,
-					   mapping_gfp_mask(file->f_mapping));
-	}
-	if (!page)
+	if (offset)
+		folio = filemap_lock_folio(file->f_mapping, index);
+	else
+		folio = filemap_grab_folio(file->f_mapping, index);
+	if (IS_ERR(folio))
 		return;
 
 	spin_lock(&fi->rdc.lock);
@@ -79,19 +77,21 @@ static void fuse_add_dirent_to_cache(struct file *file,
 	    WARN_ON(fi->rdc.pos != pos))
 		goto unlock;
 
-	addr = kmap_local_page(page);
+	folio_offset = offset_in_folio(folio, (index << PAGE_SHIFT) + offset);
 	if (!offset) {
-		clear_page(addr);
-		SetPageUptodate(page);
+		folio_fill_tail(folio, folio_offset, (const char *)dirent,
+				reclen);
+		folio_mark_uptodate(folio);
+	} else {
+		memcpy_to_folio(folio, folio_offset, (const char *)dirent,
+				reclen);
 	}
-	memcpy(addr + offset, dirent, reclen);
-	kunmap_local(addr);
 	fi->rdc.size = (index << PAGE_SHIFT) + offset + reclen;
 	fi->rdc.pos = dirent->off;
 unlock:
 	spin_unlock(&fi->rdc.lock);
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 }
 
 static void fuse_readdir_cache_end(struct file *file, loff_t pos)

-- 
2.39.5

[PATCH 2/2] fuse: convert fuse_readdir_cached() to use folios

[Tal Zussman]

Replace find_get_page_flags() with __filemap_get_folio(), and switch the
remaining page helpers to their folio equivalents.

This removes seven hidden calls to compound_head() and the last caller of
find_get_page_flags().

Signed-off-by: Tal Zussman <tz2294@columbia.edu>
---
 fs/fuse/readdir.c | 38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c
index e6b828eb41a5..5e6b3f574e90 100644
--- a/fs/fuse/readdir.c
+++ b/fs/fuse/readdir.c
@@ -502,7 +502,7 @@ static int fuse_readdir_cached(struct file *file, struct dir_context *ctx)
 	enum fuse_parse_result res;
 	pgoff_t index;
 	unsigned int size;
-	struct page *page;
+	struct folio *folio;
 	void *addr;
 
 	/* Seeked?  If so, reset the cache stream */
@@ -580,42 +580,44 @@ static int fuse_readdir_cached(struct file *file, struct dir_context *ctx)
 	if (offset_in_page(ff->readdir.cache_off) == size)
 		return 0;
 
-	page = find_get_page_flags(file->f_mapping, index,
-				   FGP_ACCESSED | FGP_LOCK);
-	/* Page gone missing, then re-added to cache, but not initialized? */
-	if (page && !PageUptodate(page)) {
-		unlock_page(page);
-		put_page(page);
-		page = NULL;
+	folio = __filemap_get_folio(file->f_mapping, index,
+				    FGP_ACCESSED | FGP_LOCK, 0);
+	if (IS_ERR(folio))
+		folio = NULL;
+	/* Folio gone missing, then re-added to cache, but not initialized? */
+	if (folio && !folio_test_uptodate(folio)) {
+		folio_unlock(folio);
+		folio_put(folio);
+		folio = NULL;
 	}
 	spin_lock(&fi->rdc.lock);
-	if (!page) {
+	if (!folio) {
 		/*
-		 * Uh-oh: page gone missing, cache is useless
+		 * Uh-oh: folio gone missing, cache is useless
 		 */
 		if (fi->rdc.version == ff->readdir.version)
 			fuse_rdc_reset(inode);
 		goto retry_locked;
 	}
 
-	/* Make sure it's still the same version after getting the page. */
+	/* Make sure it's still the same version after getting the folio. */
 	if (ff->readdir.version != fi->rdc.version) {
 		spin_unlock(&fi->rdc.lock);
-		unlock_page(page);
-		put_page(page);
+		folio_unlock(folio);
+		folio_put(folio);
 		goto retry;
 	}
 	spin_unlock(&fi->rdc.lock);
 
 	/*
-	 * Contents of the page are now protected against changing by holding
-	 * the page lock.
+	 * Contents of the folio are now protected against changing by holding
+	 * the folio lock.
 	 */
-	addr = kmap_local_page(page);
+	addr = kmap_local_folio(folio, 0);
 	res = fuse_parse_cache(ff, addr, size, ctx);
 	kunmap_local(addr);
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	if (res == FOUND_ERR)
 		return -EIO;

-- 
2.39.5

Re: [PATCH 0/2] fuse: convert the readdir cache to use folios

[Tal Zussman]

On 9/24/26 7:42 PM, Tal Zussman wrote:
> Convert the readdir cache lookups in fs/fuse/readdir.c to folios. This
> removes the last caller of find_get_page_flags() and one of the last
> callers of find_lock_page().
> 
> Based on fuse/for-next.
> 

Hi,

Following up on this. It'd be great to get this in as it would allow us
to remove find_get_page_flags() and find_lock_page() next cycle.

Thanks,
Tal


> ---
> Tal Zussman (2):
>       fuse: convert fuse_add_dirent_to_cache() to use folios
>       fuse: convert fuse_readdir_cached() to use folios
> 
>  fs/fuse/readdir.c | 70 ++++++++++++++++++++++++++++---------------------------
>  1 file changed, 36 insertions(+), 34 deletions(-)
> ---
> base-commit: 10bd6b32965265688fa277d166ab224de8e86eb2
> change-id: 20260906-fuse-readdir-folio-009ae33a7854
> 
> Best regards,
> --  
> Tal Zussman <tz2294@columbia.edu>

Re: [PATCH 0/2] fuse: convert the readdir cache to use folios

[Bernd Schubert]

On 10/13/26 18:48, Tal Zussman wrote:
> On 9/24/26 7:42 PM, Tal Zussman wrote:
>> Convert the readdir cache lookups in fs/fuse/readdir.c to folios. This
>> removes the last caller of find_get_page_flags() and one of the last
>> callers of find_lock_page().
>>
>> Based on fuse/for-next.
>>
> 
> Hi,
> 
> Following up on this. It'd be great to get this in as it would allow us
> to remove find_get_page_flags() and find_lock_page() next cycle.


fuse has large folios enabled now - the patches need to handle that.
Even if it would not be enabled yet, Joanne had spend quite some effort
to enable large folios, any change that tried to rely on behavior would
have just increased her burden...


Thanks,
Bernd

Re: [PATCH 0/2] fuse: convert the readdir cache to use folios

[Tal Zussman]

On 10/13/26 1:38 PM, Bernd Schubert wrote:
> On 10/13/26 18:48, Tal Zussman wrote:
>> On 9/24/26 7:42 PM, Tal Zussman wrote:
>>> Convert the readdir cache lookups in fs/fuse/readdir.c to folios. This
>>> removes the last caller of find_get_page_flags() and one of the last
>>> callers of find_lock_page().
>>>
>>> Based on fuse/for-next.
>>>
>> 
>> Hi,
>> 
>> Following up on this. It'd be great to get this in as it would allow us
>> to remove find_get_page_flags() and find_lock_page() next cycle.
> 
> 
> fuse has large folios enabled now - the patches need to handle that.
> Even if it would not be enabled yet, Joanne had spend quite some effort
> to enable large folios, any change that tried to rely on behavior would
> have just increased her burden...
> 
Hi Bernd,

As far as I can see, Joanne's patches enable large folios for regular files.
Here we operate on directories, which are initialized through fuse_init_dir()
and so do not use large folios. In any case, these patches switch to using
the relevant folio helpers, which would get us closer to using large folios
in the readdir cache if that's eventually desired.

Thanks,
Tal

Re: [PATCH 0/2] fuse: convert the readdir cache to use folios

[Bernd Schubert]

On 10/13/26 19:49, Tal Zussman wrote:
> On 10/13/26 1:38 PM, Bernd Schubert wrote:
>> On 10/13/26 18:48, Tal Zussman wrote:
>>> On 9/24/26 7:42 PM, Tal Zussman wrote:
>>>> Convert the readdir cache lookups in fs/fuse/readdir.c to folios. This
>>>> removes the last caller of find_get_page_flags() and one of the last
>>>> callers of find_lock_page().
>>>>
>>>> Based on fuse/for-next.
>>>>
>>>
>>> Hi,
>>>
>>> Following up on this. It'd be great to get this in as it would allow us
>>> to remove find_get_page_flags() and find_lock_page() next cycle.
>>
>>
>> fuse has large folios enabled now - the patches need to handle that.
>> Even if it would not be enabled yet, Joanne had spend quite some effort
>> to enable large folios, any change that tried to rely on behavior would
>> have just increased her burden...
>>
> Hi Bernd,
> 
> As far as I can see, Joanne's patches enable large folios for regular files.
> Here we operate on directories, which are initialized through fuse_init_dir()
> and so do not use large folios. In any case, these patches switch to using
> the relevant folio helpers, which would get us closer to using large folios
> in the readdir cache if that's eventually desired.

Hi Tal,

oops, sorry, I was bailing out when I read it as "this introduces
another stop gap for large folios". I quickly scanned over it, but don't
have much time right now - will review tomorrow morning.


Sorry again,
Bernd

Re: [PATCH 0/2] fuse: convert the readdir cache to use folios

[Tal Zussman]

On 10/13/26 2:13 PM, Bernd Schubert wrote:
> On 10/13/26 19:49, Tal Zussman wrote:
>> On 10/13/26 1:38 PM, Bernd Schubert wrote:
>>> On 10/13/26 18:48, Tal Zussman wrote:
>>>> On 9/24/26 7:42 PM, Tal Zussman wrote:
>>>>> Convert the readdir cache lookups in fs/fuse/readdir.c to folios. This
>>>>> removes the last caller of find_get_page_flags() and one of the last
>>>>> callers of find_lock_page().
>>>>>
>>>>> Based on fuse/for-next.
>>>>>
>>>>
>>>> Hi,
>>>>
>>>> Following up on this. It'd be great to get this in as it would allow us
>>>> to remove find_get_page_flags() and find_lock_page() next cycle.
>>>
>>>
>>> fuse has large folios enabled now - the patches need to handle that.
>>> Even if it would not be enabled yet, Joanne had spend quite some effort
>>> to enable large folios, any change that tried to rely on behavior would
>>> have just increased her burden...
>>>
>> Hi Bernd,
>> 
>> As far as I can see, Joanne's patches enable large folios for regular files.
>> Here we operate on directories, which are initialized through fuse_init_dir()
>> and so do not use large folios. In any case, these patches switch to using
>> the relevant folio helpers, which would get us closer to using large folios
>> in the readdir cache if that's eventually desired.
> 
> Hi Tal,
> 
> oops, sorry, I was bailing out when I read it as "this introduces
> another stop gap for large folios". I quickly scanned over it, but don't
> have much time right now - will review tomorrow morning.
> 
> 
> Sorry again,
> Bernd
> 

No problem, thanks!