Reference to non-existing CONFIG_NETFS_FSCACHE

Reference to non-existing CONFIG_NETFS_FSCACHE

[Lukas Bulwahn]

Dear David,

I have seen that you have made some recent changes in netfs now
visible in linux-next.

In commit 62c3b7481b9a ("netfs: Provide a writepages implementation"),
you have added some code that is included under #ifdef
CONFIG_NETFS_FSCACHE, but if I read the code correctly, the actual
intended config here is called CONFIG_FSCACHE. As I am not 100% sure
and this code just appeared on linux-next, I thought I would just
write you a mail rather than sending a one-line RFC patch.


Best regards,

Lukas

Re: Reference to non-existing CONFIG_NETFS_FSCACHE

[David Howells]

Lukas Bulwahn <lukas.bulwahn@gmail.com> wrote:

> In commit 62c3b7481b9a ("netfs: Provide a writepages implementation"),
> you have added some code that is included under #ifdef
> CONFIG_NETFS_FSCACHE, but if I read the code correctly, the actual
> intended config here is called CONFIG_FSCACHE.

Yeah - it should be the latter.  Something like the attached patch should fix
it.

David
---
netfs: Fix wrong #ifdef hiding wait

netfs_writepages_begin() has the wait on the fscache folio conditional on
CONFIG_NETFS_FSCACHE - which doesn't exist.

Fix it to be conditional on CONFIG_FSCACHE instead.

Fixes: 62c3b7481b9a ("netfs: Provide a writepages implementation")
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
---
 fs/netfs/buffered_write.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index 0b2b7a60dabc..de517ca70d91 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -1076,7 +1076,7 @@ static ssize_t netfs_writepages_begin(struct address_space *mapping,
 		folio_unlock(folio);
 		if (wbc->sync_mode != WB_SYNC_NONE) {
 			folio_wait_writeback(folio);
-#ifdef CONFIG_NETFS_FSCACHE
+#ifdef CONFIG_FSCACHE
 			folio_wait_fscache(folio);
 #endif
 			goto lock_again;

Re: Reference to non-existing CONFIG_NETFS_FSCACHE

[Matthew Wilcox]

On Mon, Jan 08, 2024 at 09:41:35PM +0000, David Howells wrote:
> netfs_writepages_begin() has the wait on the fscache folio conditional on
> CONFIG_NETFS_FSCACHE - which doesn't exist.
> 
> Fix it to be conditional on CONFIG_FSCACHE instead.

Why is it conditional at all?  Why don't we have a stub function if
CONFIG_FSCACHE is not defined?

Re: Reference to non-existing CONFIG_NETFS_FSCACHE

[David Howells]

Matthew Wilcox <willy@infradead.org> wrote:

> > netfs_writepages_begin() has the wait on the fscache folio conditional on
> > CONFIG_NETFS_FSCACHE - which doesn't exist.
> > 
> > Fix it to be conditional on CONFIG_FSCACHE instead.
> 
> Why is it conditional at all?  Why don't we have a stub function if
> CONFIG_FSCACHE is not defined?

At this point, I'd rather just change the #ifdef and then (hopefully) next
cycle get rid of PG_fscache entirely, rendering this unnecessary.

David