diff mbox series

[2/2] erofs: use netfs helpers manipulating request and subrequest

Message ID 20221021084912.61468-3-jefflexu@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series netfs,erofs: reuse netfs_put_subrequest() and | expand

Commit Message

Jingbo Xu Oct. 21, 2022, 8:49 a.m. UTC 
Use netfs_put_subrequest() and netfs_rreq_completed() completing request
and subrequest.

It is worth noting that a noop netfs_request_ops is introduced for erofs
since some netfs routine, e.g. netfs_free_request(), will call into
this ops.

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
---
 fs/erofs/fscache.c | 47 ++++++++++------------------------------------
 1 file changed, 10 insertions(+), 37 deletions(-)

Comments

Gao Xiang Oct. 21, 2022, 9:09 a.m. UTC | #1 
On Fri, Oct 21, 2022 at 04:49:12PM +0800, Jingbo Xu wrote:
> Use netfs_put_subrequest() and netfs_rreq_completed() completing request
> and subrequest.
> 
> It is worth noting that a noop netfs_request_ops is introduced for erofs
> since some netfs routine, e.g. netfs_free_request(), will call into
> this ops.
> 
> Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>

Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Thanks,
Gao Xiang

> ---
>  fs/erofs/fscache.c | 47 ++++++++++------------------------------------
>  1 file changed, 10 insertions(+), 37 deletions(-)
> 
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index fe05bc51f9f2..fa3f4ab5e3b6 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -4,6 +4,7 @@
>   * Copyright (C) 2022, Bytedance Inc. All rights reserved.
>   */
>  #include <linux/fscache.h>
> +#include <trace/events/netfs.h>
>  #include "internal.h"
>  
>  static DEFINE_MUTEX(erofs_domain_list_lock);
> @@ -11,6 +12,8 @@ static DEFINE_MUTEX(erofs_domain_cookies_lock);
>  static LIST_HEAD(erofs_domain_list);
>  static struct vfsmount *erofs_pseudo_mnt;
>  
> +static const struct netfs_request_ops erofs_noop_req_ops;
> +
>  static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space *mapping,
>  					     loff_t start, size_t len)
>  {
> @@ -24,40 +27,12 @@ static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space
>  	rreq->len	= len;
>  	rreq->mapping	= mapping;
>  	rreq->inode	= mapping->host;
> +	rreq->netfs_ops	= &erofs_noop_req_ops;
>  	INIT_LIST_HEAD(&rreq->subrequests);
>  	refcount_set(&rreq->ref, 1);
>  	return rreq;
>  }
>  
> -static void erofs_fscache_put_request(struct netfs_io_request *rreq)
> -{
> -	if (!refcount_dec_and_test(&rreq->ref))
> -		return;
> -	if (rreq->cache_resources.ops)
> -		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
> -	kfree(rreq);
> -}
> -
> -static void erofs_fscache_put_subrequest(struct netfs_io_subrequest *subreq)
> -{
> -	if (!refcount_dec_and_test(&subreq->ref))
> -		return;
> -	erofs_fscache_put_request(subreq->rreq);
> -	kfree(subreq);
> -}
> -
> -static void erofs_fscache_clear_subrequests(struct netfs_io_request *rreq)
> -{
> -	struct netfs_io_subrequest *subreq;
> -
> -	while (!list_empty(&rreq->subrequests)) {
> -		subreq = list_first_entry(&rreq->subrequests,
> -				struct netfs_io_subrequest, rreq_link);
> -		list_del(&subreq->rreq_link);
> -		erofs_fscache_put_subrequest(subreq);
> -	}
> -}
> -
>  static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
>  {
>  	struct netfs_io_subrequest *subreq;
> @@ -114,11 +89,10 @@ static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
>  static void erofs_fscache_rreq_complete(struct netfs_io_request *rreq)
>  {
>  	erofs_fscache_rreq_unlock_folios(rreq);
> -	erofs_fscache_clear_subrequests(rreq);
> -	erofs_fscache_put_request(rreq);
> +	netfs_rreq_completed(rreq, false);
>  }
>  
> -static void erofc_fscache_subreq_complete(void *priv,
> +static void erofs_fscache_subreq_complete(void *priv,
>  		ssize_t transferred_or_error, bool was_async)
>  {
>  	struct netfs_io_subrequest *subreq = priv;
> @@ -130,7 +104,7 @@ static void erofc_fscache_subreq_complete(void *priv,
>  	if (atomic_dec_and_test(&rreq->nr_outstanding))
>  		erofs_fscache_rreq_complete(rreq);
>  
> -	erofs_fscache_put_subrequest(subreq);
> +	netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_terminated);
>  }
>  
>  /*
> @@ -171,9 +145,8 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
>  		}
>  
>  		subreq->start = pstart + done;
> -		subreq->len	=  len - done;
> +		subreq->len   =  len - done;
>  		subreq->flags = 1 << NETFS_SREQ_ONDEMAND;
> -
>  		list_add_tail(&subreq->rreq_link, &rreq->subrequests);
>  
>  		source = cres->ops->prepare_read(subreq, LLONG_MAX);
> @@ -184,7 +157,7 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
>  				  source);
>  			ret = -EIO;
>  			subreq->error = ret;
> -			erofs_fscache_put_subrequest(subreq);
> +			netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_failed);
>  			goto out;
>  		}
>  
> @@ -195,7 +168,7 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
>  
>  		ret = fscache_read(cres, subreq->start, &iter,
>  				   NETFS_READ_HOLE_FAIL,
> -				   erofc_fscache_subreq_complete, subreq);
> +				   erofs_fscache_subreq_complete, subreq);
>  		if (ret == -EIOCBQUEUED)
>  			ret = 0;
>  		if (ret) {
> -- 
> 2.19.1.6.gb485710b
Jeff Layton Oct. 21, 2022, 12:38 p.m. UTC | #2 
On Fri, 2022-10-21 at 16:49 +0800, Jingbo Xu wrote:
> Use netfs_put_subrequest() and netfs_rreq_completed() completing request
> and subrequest.
> 
> It is worth noting that a noop netfs_request_ops is introduced for erofs
> since some netfs routine, e.g. netfs_free_request(), will call into
> this ops.
> 
> Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
> ---
>  fs/erofs/fscache.c | 47 ++++++++++------------------------------------
>  1 file changed, 10 insertions(+), 37 deletions(-)
> 
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index fe05bc51f9f2..fa3f4ab5e3b6 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -4,6 +4,7 @@
>   * Copyright (C) 2022, Bytedance Inc. All rights reserved.
>   */
>  #include <linux/fscache.h>
> +#include <trace/events/netfs.h>
>  #include "internal.h"
>  
>  static DEFINE_MUTEX(erofs_domain_list_lock);
> @@ -11,6 +12,8 @@ static DEFINE_MUTEX(erofs_domain_cookies_lock);
>  static LIST_HEAD(erofs_domain_list);
>  static struct vfsmount *erofs_pseudo_mnt;
>  
> +static const struct netfs_request_ops erofs_noop_req_ops;
> +
>  static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space *mapping,
>  					     loff_t start, size_t len)
>  {
> @@ -24,40 +27,12 @@ static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space
>  	rreq->len	= len;
>  	rreq->mapping	= mapping;
>  	rreq->inode	= mapping->host;
> +	rreq->netfs_ops	= &erofs_noop_req_ops;
>  	INIT_LIST_HEAD(&rreq->subrequests);
>  	refcount_set(&rreq->ref, 1);
>  	return rreq;
>  }
>  

Why is erofs allocating its own netfs structures? This seems quite
fragile, and a layering violation too.

> -static void erofs_fscache_put_request(struct netfs_io_request *rreq)
> -{
> -	if (!refcount_dec_and_test(&rreq->ref))
> -		return;
> -	if (rreq->cache_resources.ops)
> -		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
> -	kfree(rreq);
> -}
> -
> -static void erofs_fscache_put_subrequest(struct netfs_io_subrequest *subreq)
> -{
> -	if (!refcount_dec_and_test(&subreq->ref))
> -		return;
> -	erofs_fscache_put_request(subreq->rreq);
> -	kfree(subreq);
> -}
> -
> -static void erofs_fscache_clear_subrequests(struct netfs_io_request *rreq)
> -{
> -	struct netfs_io_subrequest *subreq;
> -
> -	while (!list_empty(&rreq->subrequests)) {
> -		subreq = list_first_entry(&rreq->subrequests,
> -				struct netfs_io_subrequest, rreq_link);
> -		list_del(&subreq->rreq_link);
> -		erofs_fscache_put_subrequest(subreq);
> -	}
> -}
> -
>  static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
>  {
>  	struct netfs_io_subrequest *subreq;
> @@ -114,11 +89,10 @@ static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
>  static void erofs_fscache_rreq_complete(struct netfs_io_request *rreq)
>  {
>  	erofs_fscache_rreq_unlock_folios(rreq);
> -	erofs_fscache_clear_subrequests(rreq);
> -	erofs_fscache_put_request(rreq);
> +	netfs_rreq_completed(rreq, false);
>  }
>  
> -static void erofc_fscache_subreq_complete(void *priv,
> +static void erofs_fscache_subreq_complete(void *priv,
>  		ssize_t transferred_or_error, bool was_async)
>  {
>  	struct netfs_io_subrequest *subreq = priv;
> @@ -130,7 +104,7 @@ static void erofc_fscache_subreq_complete(void *priv,
>  	if (atomic_dec_and_test(&rreq->nr_outstanding))
>  		erofs_fscache_rreq_complete(rreq);
>  
> -	erofs_fscache_put_subrequest(subreq);
> +	netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_terminated);
>  }
>  
>  /*
> @@ -171,9 +145,8 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
>  		}
>  
>  		subreq->start = pstart + done;
> -		subreq->len	=  len - done;
> +		subreq->len   =  len - done;
>  		subreq->flags = 1 << NETFS_SREQ_ONDEMAND;
> -
>  		list_add_tail(&subreq->rreq_link, &rreq->subrequests);
>  
>  		source = cres->ops->prepare_read(subreq, LLONG_MAX);
> @@ -184,7 +157,7 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
>  				  source);
>  			ret = -EIO;
>  			subreq->error = ret;
> -			erofs_fscache_put_subrequest(subreq);
> +			netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_failed);
>  			goto out;
>  		}
>  
> @@ -195,7 +168,7 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
>  
>  		ret = fscache_read(cres, subreq->start, &iter,
>  				   NETFS_READ_HOLE_FAIL,
> -				   erofc_fscache_subreq_complete, subreq);
> +				   erofs_fscache_subreq_complete, subreq);
>  		if (ret == -EIOCBQUEUED)
>  			ret = 0;
>  		if (ret) {

I'd rather see this done differently. Either change erofs to use the
netfs infrastructure in a more standard fashion, or maybe consider
teaching erofs to talk to cachefiles directly?

IDK, but this sort of mucking around in the low level netfs objects
seems wrong to me.
Gao Xiang Oct. 21, 2022, 1:55 p.m. UTC | #3 
Hi Jeff,

On Fri, Oct 21, 2022 at 08:38:38AM -0400, Jeff Layton wrote:
> On Fri, 2022-10-21 at 16:49 +0800, Jingbo Xu wrote:
> > Use netfs_put_subrequest() and netfs_rreq_completed() completing request
> > and subrequest.
> > 
> > It is worth noting that a noop netfs_request_ops is introduced for erofs
> > since some netfs routine, e.g. netfs_free_request(), will call into
> > this ops.
> > 
> > Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
> > ---
> >  fs/erofs/fscache.c | 47 ++++++++++------------------------------------
> >  1 file changed, 10 insertions(+), 37 deletions(-)
> > 
> > diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> > index fe05bc51f9f2..fa3f4ab5e3b6 100644
> > --- a/fs/erofs/fscache.c
> > +++ b/fs/erofs/fscache.c
> > @@ -4,6 +4,7 @@
> >   * Copyright (C) 2022, Bytedance Inc. All rights reserved.
> >   */
> >  #include <linux/fscache.h>
> > +#include <trace/events/netfs.h>
> >  #include "internal.h"
> >  
> >  static DEFINE_MUTEX(erofs_domain_list_lock);
> > @@ -11,6 +12,8 @@ static DEFINE_MUTEX(erofs_domain_cookies_lock);
> >  static LIST_HEAD(erofs_domain_list);
> >  static struct vfsmount *erofs_pseudo_mnt;
> >  
> > +static const struct netfs_request_ops erofs_noop_req_ops;
> > +
> >  static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space *mapping,
> >  					     loff_t start, size_t len)
> >  {
> > @@ -24,40 +27,12 @@ static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space
> >  	rreq->len	= len;
> >  	rreq->mapping	= mapping;
> >  	rreq->inode	= mapping->host;
> > +	rreq->netfs_ops	= &erofs_noop_req_ops;
> >  	INIT_LIST_HEAD(&rreq->subrequests);
> >  	refcount_set(&rreq->ref, 1);
> >  	return rreq;
> >  }
> >  
> 
> Why is erofs allocating its own netfs structures? This seems quite
> fragile, and a layering violation too.

Thanks for the reply.

I've talked this to David on IRC about this as well.  Actually what we
really want to use is to do raw I/O requests directly to
fscache/cachefiles.

Because as I said for many times, new netfs per-inode cookie model
doesn't suit for erofs use cases.  Since we treat each cookie as a
data blob, and each erofs inode can refer to one or more blobs in
the chunk-deduplicated way.

So we need a raw I/O data request to fscache/cachefiles.  I'm not sure
if it will also be a future feature request (raw I/O request on cookies)
for network fses in order to get some special file data/metadata.

> 
> > -static void erofs_fscache_put_request(struct netfs_io_request *rreq)
> > -{
> > -	if (!refcount_dec_and_test(&rreq->ref))
> > -		return;
> > -	if (rreq->cache_resources.ops)
> > -		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
> > -	kfree(rreq);
> > -}
> > -
> > -static void erofs_fscache_put_subrequest(struct netfs_io_subrequest *subreq)
> > -{
> > -	if (!refcount_dec_and_test(&subreq->ref))
> > -		return;
> > -	erofs_fscache_put_request(subreq->rreq);
> > -	kfree(subreq);
> > -}
> > -
> > -static void erofs_fscache_clear_subrequests(struct netfs_io_request *rreq)
> > -{
> > -	struct netfs_io_subrequest *subreq;
> > -
> > -	while (!list_empty(&rreq->subrequests)) {
> > -		subreq = list_first_entry(&rreq->subrequests,
> > -				struct netfs_io_subrequest, rreq_link);
> > -		list_del(&subreq->rreq_link);
> > -		erofs_fscache_put_subrequest(subreq);
> > -	}
> > -}
> > -
> >  static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
> >  {
> >  	struct netfs_io_subrequest *subreq;
> > @@ -114,11 +89,10 @@ static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
> >  static void erofs_fscache_rreq_complete(struct netfs_io_request *rreq)
> >  {
> >  	erofs_fscache_rreq_unlock_folios(rreq);
> > -	erofs_fscache_clear_subrequests(rreq);
> > -	erofs_fscache_put_request(rreq);
> > +	netfs_rreq_completed(rreq, false);
> >  }
> >  
> > -static void erofc_fscache_subreq_complete(void *priv,
> > +static void erofs_fscache_subreq_complete(void *priv,
> >  		ssize_t transferred_or_error, bool was_async)
> >  {
> >  	struct netfs_io_subrequest *subreq = priv;
> > @@ -130,7 +104,7 @@ static void erofc_fscache_subreq_complete(void *priv,
> >  	if (atomic_dec_and_test(&rreq->nr_outstanding))
> >  		erofs_fscache_rreq_complete(rreq);
> >  
> > -	erofs_fscache_put_subrequest(subreq);
> > +	netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_terminated);
> >  }
> >  
> >  /*
> > @@ -171,9 +145,8 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
> >  		}
> >  
> >  		subreq->start = pstart + done;
> > -		subreq->len	=  len - done;
> > +		subreq->len   =  len - done;
> >  		subreq->flags = 1 << NETFS_SREQ_ONDEMAND;
> > -
> >  		list_add_tail(&subreq->rreq_link, &rreq->subrequests);
> >  
> >  		source = cres->ops->prepare_read(subreq, LLONG_MAX);
> > @@ -184,7 +157,7 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
> >  				  source);
> >  			ret = -EIO;
> >  			subreq->error = ret;
> > -			erofs_fscache_put_subrequest(subreq);
> > +			netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_failed);
> >  			goto out;
> >  		}
> >  
> > @@ -195,7 +168,7 @@ static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
> >  
> >  		ret = fscache_read(cres, subreq->start, &iter,
> >  				   NETFS_READ_HOLE_FAIL,
> > -				   erofc_fscache_subreq_complete, subreq);
> > +				   erofs_fscache_subreq_complete, subreq);
> >  		if (ret == -EIOCBQUEUED)
> >  			ret = 0;
> >  		if (ret) {
> 
> I'd rather see this done differently. Either change erofs to use the
> netfs infrastructure in a more standard fashion, or maybe consider
> teaching erofs to talk to cachefiles directly?

I've requested David on IRC to shift netfs_io_request and
netfs_io_subrequest into a more natural new prefix other than
(netfs or fscache) but we didn't get into a proper conclusion (David
don't want to use fscache_ since fscache can be disabled but netfs
can still work.)

Like what we said for many times before, the reason why EROFS uses
fscache/cachefiles infrastructure is that we don't want to
duplicate/reinvent another same caching subsystem in order to manage
local caching in order to do lazy pulling / on-demand read, and the
majority code can be shared other than exist the same two codebases
to do the same thing, also:

content map: https://listman.redhat.com/archives/linux-cachefs/2022-August/007050.html

Also if we have the only one caching subsystem, the main codebase can
be tested better compared with two duplicated ones.

And I think overlayfs can also use it for partial copy up as anyone
interested.

> 
> IDK, but this sort of mucking around in the low level netfs objects
> seems wrong to me.

My suggestion is to abstract natural raw data interfaces for all fses
to use, rather than expose a per-inode cookie netfs interface only.

Thanks,
Gao Xiang

> -- 
> Jeff Layton <jlayton@kernel.org>
diff mbox series

Patch

diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index fe05bc51f9f2..fa3f4ab5e3b6 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -4,6 +4,7 @@ 
  * Copyright (C) 2022, Bytedance Inc. All rights reserved.
  */
 #include <linux/fscache.h>
+#include <trace/events/netfs.h>
 #include "internal.h"
 
 static DEFINE_MUTEX(erofs_domain_list_lock);
@@ -11,6 +12,8 @@  static DEFINE_MUTEX(erofs_domain_cookies_lock);
 static LIST_HEAD(erofs_domain_list);
 static struct vfsmount *erofs_pseudo_mnt;
 
+static const struct netfs_request_ops erofs_noop_req_ops;
+
 static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space *mapping,
 					     loff_t start, size_t len)
 {
@@ -24,40 +27,12 @@  static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space
 	rreq->len	= len;
 	rreq->mapping	= mapping;
 	rreq->inode	= mapping->host;
+	rreq->netfs_ops	= &erofs_noop_req_ops;
 	INIT_LIST_HEAD(&rreq->subrequests);
 	refcount_set(&rreq->ref, 1);
 	return rreq;
 }
 
-static void erofs_fscache_put_request(struct netfs_io_request *rreq)
-{
-	if (!refcount_dec_and_test(&rreq->ref))
-		return;
-	if (rreq->cache_resources.ops)
-		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
-	kfree(rreq);
-}
-
-static void erofs_fscache_put_subrequest(struct netfs_io_subrequest *subreq)
-{
-	if (!refcount_dec_and_test(&subreq->ref))
-		return;
-	erofs_fscache_put_request(subreq->rreq);
-	kfree(subreq);
-}
-
-static void erofs_fscache_clear_subrequests(struct netfs_io_request *rreq)
-{
-	struct netfs_io_subrequest *subreq;
-
-	while (!list_empty(&rreq->subrequests)) {
-		subreq = list_first_entry(&rreq->subrequests,
-				struct netfs_io_subrequest, rreq_link);
-		list_del(&subreq->rreq_link);
-		erofs_fscache_put_subrequest(subreq);
-	}
-}
-
 static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
 {
 	struct netfs_io_subrequest *subreq;
@@ -114,11 +89,10 @@  static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq)
 static void erofs_fscache_rreq_complete(struct netfs_io_request *rreq)
 {
 	erofs_fscache_rreq_unlock_folios(rreq);
-	erofs_fscache_clear_subrequests(rreq);
-	erofs_fscache_put_request(rreq);
+	netfs_rreq_completed(rreq, false);
 }
 
-static void erofc_fscache_subreq_complete(void *priv,
+static void erofs_fscache_subreq_complete(void *priv,
 		ssize_t transferred_or_error, bool was_async)
 {
 	struct netfs_io_subrequest *subreq = priv;
@@ -130,7 +104,7 @@  static void erofc_fscache_subreq_complete(void *priv,
 	if (atomic_dec_and_test(&rreq->nr_outstanding))
 		erofs_fscache_rreq_complete(rreq);
 
-	erofs_fscache_put_subrequest(subreq);
+	netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_terminated);
 }
 
 /*
@@ -171,9 +145,8 @@  static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
 		}
 
 		subreq->start = pstart + done;
-		subreq->len	=  len - done;
+		subreq->len   =  len - done;
 		subreq->flags = 1 << NETFS_SREQ_ONDEMAND;
-
 		list_add_tail(&subreq->rreq_link, &rreq->subrequests);
 
 		source = cres->ops->prepare_read(subreq, LLONG_MAX);
@@ -184,7 +157,7 @@  static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
 				  source);
 			ret = -EIO;
 			subreq->error = ret;
-			erofs_fscache_put_subrequest(subreq);
+			netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_failed);
 			goto out;
 		}
 
@@ -195,7 +168,7 @@  static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie,
 
 		ret = fscache_read(cres, subreq->start, &iter,
 				   NETFS_READ_HOLE_FAIL,
-				   erofc_fscache_subreq_complete, subreq);
+				   erofs_fscache_subreq_complete, subreq);
 		if (ret == -EIOCBQUEUED)
 			ret = 0;
 		if (ret) {