From: David Howells <dhowells@redhat.com> To: Christian Brauner <christian@brauner.io>, Jeff Layton <jlayton@kernel.org>, Gao Xiang <hsiangkao@linux.alibaba.com>, Dominique Martinet <asmadeus@codewreck.org> Cc: David Howells <dhowells@redhat.com>, Steve French <smfrench@gmail.com>, Matthew Wilcox <willy@infradead.org>, Marc Dionne <marc.dionne@auristor.com>, Paulo Alcantara <pc@manguebit.com>, Shyam Prasad N <sprasad@microsoft.com>, Tom Talpey <tom@talpey.com>, Eric Van Hensbergen <ericvh@kernel.org>, Ilya Dryomov <idryomov@gmail.com>, linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/6] netfs: Fix the loop that unmarks folios after writing to the cache Date: Tue, 9 Jan 2024 11:20:21 +0000 [thread overview] Message-ID: <20240109112029.1572463-5-dhowells@redhat.com> (raw) In-Reply-To: <20240109112029.1572463-1-dhowells@redhat.com> In the loop in netfs_rreq_unmark_after_write() that removes the PG_fscache from folios after they've been written to the cache, as soon as we remove the mark from a multipage folio, it can get split - and then we might see a fragment of folio again. Guard against this by advancing the 'unlocked' tracker to the index of the last page in the folio to avoid a double removal of the PG_fscache mark. Reported-by: Marc Dionne <marc.dionne@auristor.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 | 1 + fs/netfs/io.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 6cd8f7422e9a..0b2b7a60dabc 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -698,6 +698,7 @@ static void netfs_pages_written_back(struct netfs_io_request *wreq) end_wb: if (folio_test_fscache(folio)) folio_end_fscache(folio); + xas_advance(&xas, folio_next_index(folio) - 1); folio_end_writeback(folio); } diff --git a/fs/netfs/io.c b/fs/netfs/io.c index 5b5af96cd4b9..4309edf33862 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -126,7 +126,7 @@ static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq, */ if (have_unlocked && folio_index(folio) <= unlocked) continue; - unlocked = folio_index(folio); + unlocked = folio_next_index(folio) - 1; trace_netfs_folio(folio, netfs_folio_trace_end_copy); folio_end_fscache(folio); have_unlocked = true;
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com> To: Christian Brauner <christian@brauner.io>, Jeff Layton <jlayton@kernel.org>, Gao Xiang <hsiangkao@linux.alibaba.com>, Dominique Martinet <asmadeus@codewreck.org> Cc: Paulo Alcantara <pc@manguebit.com>, Tom Talpey <tom@talpey.com>, Shyam Prasad N <sprasad@microsoft.com>, linux-cifs@vger.kernel.org, netdev@vger.kernel.org, v9fs@lists.linux.dev, ceph-devel@vger.kernel.org, linux-nfs@vger.kernel.org, Matthew Wilcox <willy@infradead.org>, linux-kernel@vger.kernel.org, David Howells <dhowells@redhat.com>, Steve French <smfrench@gmail.com>, linux-cachefs@redhat.com, linux-mm@kvack.org, Marc Dionne <marc.dionne@auristor.com>, linux-fsdevel@vger.kernel.org, Ilya Dryomov <idryomov@gmail.com>, Eric Van Hensbergen <ericvh@kernel.org>, linux-erofs@lists.ozlabs.org, linux-afs@lists.infradead.org Subject: [PATCH 4/6] netfs: Fix the loop that unmarks folios after writing to the cache Date: Tue, 9 Jan 2024 11:20:21 +0000 [thread overview] Message-ID: <20240109112029.1572463-5-dhowells@redhat.com> (raw) In-Reply-To: <20240109112029.1572463-1-dhowells@redhat.com> In the loop in netfs_rreq_unmark_after_write() that removes the PG_fscache from folios after they've been written to the cache, as soon as we remove the mark from a multipage folio, it can get split - and then we might see a fragment of folio again. Guard against this by advancing the 'unlocked' tracker to the index of the last page in the folio to avoid a double removal of the PG_fscache mark. Reported-by: Marc Dionne <marc.dionne@auristor.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 | 1 + fs/netfs/io.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 6cd8f7422e9a..0b2b7a60dabc 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -698,6 +698,7 @@ static void netfs_pages_written_back(struct netfs_io_request *wreq) end_wb: if (folio_test_fscache(folio)) folio_end_fscache(folio); + xas_advance(&xas, folio_next_index(folio) - 1); folio_end_writeback(folio); } diff --git a/fs/netfs/io.c b/fs/netfs/io.c index 5b5af96cd4b9..4309edf33862 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -126,7 +126,7 @@ static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq, */ if (have_unlocked && folio_index(folio) <= unlocked) continue; - unlocked = folio_index(folio); + unlocked = folio_next_index(folio) - 1; trace_netfs_folio(folio, netfs_folio_trace_end_copy); folio_end_fscache(folio); have_unlocked = true;
next prev parent reply other threads:[~2024-01-09 11:20 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-01-09 11:20 [PATCH 0/6] netfs, cachefiles: More additional patches David Howells 2024-01-09 11:20 ` David Howells 2024-01-09 11:20 ` [PATCH 1/6] netfs: Mark netfs_unbuffered_write_iter_locked() static David Howells 2024-01-09 11:20 ` David Howells 2024-01-09 11:20 ` [PATCH 2/6] netfs: Count DIO writes David Howells 2024-01-09 11:20 ` David Howells 2024-01-09 11:20 ` [PATCH 3/6] netfs: Fix interaction between write-streaming and cachefiles culling David Howells 2024-01-09 11:20 ` David Howells 2024-01-09 11:20 ` David Howells [this message] 2024-01-09 11:20 ` [PATCH 4/6] netfs: Fix the loop that unmarks folios after writing to the cache David Howells 2024-01-09 11:20 ` [PATCH 5/6] cachefiles: Fix signed/unsigned mixup David Howells 2024-01-09 11:20 ` David Howells 2024-01-09 13:03 ` Gao Xiang 2024-01-09 13:03 ` Gao Xiang 2024-01-10 12:05 ` [External] " Jia Zhu 2024-01-10 12:05 ` Jia Zhu via Linux-erofs 2024-01-09 11:20 ` [PATCH 6/6] netfs: Fix wrong #ifdef hiding wait David Howells 2024-01-09 11:20 ` David Howells 2024-01-09 17:11 ` [PATCH 0/6] netfs, cachefiles: More additional patches Marc Dionne 2024-01-09 17:11 ` Marc Dionne 2024-01-09 18:37 ` Jeff Layton 2024-01-09 18:37 ` Jeff Layton
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