From: David Howells <dhowells@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: dhowells@redhat.com, Matthew Wilcox <willy@infradead.org>,
Jeff Layton <jlayton@redhat.com>,
David Wysochanski <dwysocha@redhat.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Trond Myklebust <trondmy@hammerspace.com>,
Steve French <sfrench@samba.org>,
Dominique Martinet <asmadeus@codewreck.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
ceph-devel@vger.kernel.org, linux-afs@lists.infradead.org,
linux-cachefs@redhat.com, CIFS <linux-cifs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"open list:NFS, SUNRPC, AND..." <linux-nfs@vger.kernel.org>,
v9fs-developer@lists.sourceforge.net,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [GIT PULL] fscache: I/O API modernisation and netfs helper library
Date: Wed, 10 Feb 2021 16:36:33 +0000 [thread overview]
Message-ID: <1331025.1612974993@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAHk-=wh+2gbF7XEjYc=HV9w_2uVzVf7vs60BPz0gFA=+pUm3ww@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> Does the code not hold a refcount already?
The attached patch will do that. Note that it's currently based on top of the
patch that drops the PG_fscache alias, so it refers to PG_private_2.
I've run all three patches through xfstests over afs, both with and without a
cache, and Jeff has tested ceph with them.
David
---
commit 803a09110b41b9f6091a517fc8f5c4b15475048c
Author: David Howells <dhowells@redhat.com>
Date: Wed Feb 10 11:35:15 2021 +0000
netfs: Hold a ref on a page when PG_private_2 is set
Take a reference on a page when PG_private_2 is set and drop it once the
bit is unlocked.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index 9018224693e9..043d96ca2aad 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -10,6 +10,7 @@
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
+#include <linux/pagevec.h>
#include <linux/slab.h>
#include <linux/uio.h>
#include <linux/sched/mm.h>
@@ -230,10 +231,13 @@ static void netfs_rreq_completed(struct netfs_read_request *rreq)
static void netfs_rreq_unmark_after_write(struct netfs_read_request *rreq)
{
struct netfs_read_subrequest *subreq;
+ struct pagevec pvec;
struct page *page;
pgoff_t unlocked = 0;
bool have_unlocked = false;
+ pagevec_init(&pvec);
+
rcu_read_lock();
list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
@@ -247,6 +251,8 @@ static void netfs_rreq_unmark_after_write(struct netfs_read_request *rreq)
continue;
unlocked = page->index;
unlock_page_private_2(page);
+ if (pagevec_add(&pvec, page) == 0)
+ pagevec_release(&pvec);
have_unlocked = true;
}
}
@@ -403,8 +409,10 @@ static void netfs_rreq_unlock(struct netfs_read_request *rreq)
pg_failed = true;
break;
}
- if (test_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags))
+ if (test_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags)) {
+ get_page(page);
SetPagePrivate2(page);
+ }
pg_failed |= subreq_failed;
if (pgend < iopos + subreq->len)
break;
next prev parent reply other threads:[~2021-02-10 16:43 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 16:09 [GIT PULL] fscache: I/O API modernisation and netfs helper library David Howells
2021-02-09 19:06 ` Linus Torvalds
2021-02-09 19:45 ` Jeff Layton
2021-02-09 20:21 ` Matthew Wilcox
2021-02-09 21:19 ` Linus Torvalds
2021-02-09 21:55 ` David Howells
2021-02-10 16:36 ` David Howells [this message]
2021-02-09 21:25 ` David Howells
2021-02-09 22:42 ` David Wysochanski
2021-02-09 21:10 ` David Howells
2021-02-10 16:29 ` David Howells
2021-02-10 16:33 ` David Howells
2021-02-10 20:43 ` Linus Torvalds
2021-02-11 22:38 ` David Howells
2021-02-11 23:20 ` David Howells
2021-02-12 16:40 ` David Wysochanski
2021-02-13 1:05 ` Linus Torvalds
2021-02-15 0:22 ` David Howells
2021-02-15 1:01 ` Linus Torvalds
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