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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH v4 13/28] netfs: Hold a ref on a page when PG_private_2 is set From: David Howells To: Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet Cc: Linus Torvalds , Matthew Wilcox , Linus Torvalds , linux-mm@kvack.org, linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, dhowells@redhat.com, Jeff Layton , David Wysochanski , "Matthew Wilcox (Oracle)" , Alexander Viro , linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 10 Mar 2021 16:57:24 +0000 Message-ID: <161539544426.286939.4484560053278261236.stgit@warthog.procyon.org.uk> In-Reply-To: <161539526152.286939.8589700175877370401.stgit@warthog.procyon.org.uk> References: <161539526152.286939.8589700175877370401.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Take a reference on a page when PG_private_2 is set and drop it once the bit is unlocked[1]. Reported-by: Linus Torvalds Signed-off-by: David Howells cc: Matthew Wilcox cc: Linus Torvalds cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/CAHk-=wh+2gbF7XEjYc=HV9w_2uVzVf7vs60BPz0gFA=+pUm3ww@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/1331025.1612974993@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/161340400833.1303470.8070750156044982282.stgit@warthog.procyon.org.uk/ # v3 --- fs/netfs/read_helper.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index 0a7b76c11c98..ce11ca4c32e4 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -238,10 +239,13 @@ static void netfs_rreq_unmark_after_write(struct netfs_read_request *rreq, bool was_async) { 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) { @@ -255,6 +259,8 @@ static void netfs_rreq_unmark_after_write(struct netfs_read_request *rreq, continue; unlocked = page->index; unlock_page_fscache(page); + if (pagevec_add(&pvec, page) == 0) + pagevec_release(&pvec); have_unlocked = true; } } @@ -413,8 +419,10 @@ 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); SetPageFsCache(page); + } pg_failed |= subreq_failed; if (pgend < iopos + subreq->len) break;