4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit ad3cba223ac02dc769c3bbe88efe277bbb457566 ]
When we use direct_IO with an NFS backing store, we can trigger a WARNING in __set_page_dirty(), as below, since we're dirtying the page unnecessarily in nfs_direct_read_completion().
To fix, replicate the logic in commit 53cbf3b157a0 ("fs: direct-io: don't dirtying pages for ITER_BVEC/ITER_KVEC direct read").
Other filesystems that implement direct_IO handle this; most use blockdev_direct_IO(). ceph and cifs have similar logic.
mount 127.0.0.1:/export /nfs dd if=/dev/zero of=/nfs/image bs=1M count=200 losetup --direct-io=on -f /nfs/image mkfs.btrfs /dev/loop0 mount -t btrfs /dev/loop0 /mnt/
kernel: WARNING: CPU: 0 PID: 8067 at fs/buffer.c:580 __set_page_dirty+0xaf/0xd0 kernel: Modules linked in: loop(E) nfsv3(E) rpcsec_gss_krb5(E) nfsv4(E) dns_resolver(E) nfs(E) fscache(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) fuse(E) tun(E) ip6t_rpfilter(E) ipt_REJECT(E) nf_ kernel: snd_seq(E) snd_seq_device(E) snd_pcm(E) video(E) snd_timer(E) snd(E) soundcore(E) ip_tables(E) xfs(E) libcrc32c(E) sd_mod(E) sr_mod(E) cdrom(E) ata_generic(E) pata_acpi(E) crc32c_intel(E) ahci(E) li kernel: CPU: 0 PID: 8067 Comm: kworker/0:2 Tainted: G E 4.20.0-rc1.master.20181111.ol7.x86_64 #1 kernel: Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 kernel: Workqueue: nfsiod rpc_async_release [sunrpc] kernel: RIP: 0010:__set_page_dirty+0xaf/0xd0 kernel: Code: c3 48 8b 02 f6 c4 04 74 d4 48 89 df e8 ba 05 f7 ff 48 89 c6 eb cb 48 8b 43 08 a8 01 75 1f 48 89 d8 48 8b 00 a8 04 74 02 eb 87 <0f> 0b eb 83 48 83 e8 01 eb 9f 48 83 ea 01 0f 1f 00 eb 8b 48 83 e8 kernel: RSP: 0000:ffffc1c8825b7d78 EFLAGS: 00013046 kernel: RAX: 000fffffc0020089 RBX: fffff2b603308b80 RCX: 0000000000000001 kernel: RDX: 0000000000000001 RSI: ffff9d11478115c8 RDI: ffff9d11478115d0 kernel: RBP: ffffc1c8825b7da0 R08: 0000646f6973666e R09: 8080808080808080 kernel: R10: 0000000000000001 R11: 0000000000000000 R12: ffff9d11478115d0 kernel: R13: ffff9d11478115c8 R14: 0000000000003246 R15: 0000000000000001 kernel: FS: 0000000000000000(0000) GS:ffff9d115ba00000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 00007f408686f640 CR3: 0000000104d8e004 CR4: 00000000000606f0 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 kernel: Call Trace: kernel: __set_page_dirty_buffers+0xb6/0x110 kernel: set_page_dirty+0x52/0xb0 kernel: nfs_direct_read_completion+0xc4/0x120 [nfs] kernel: nfs_pgio_release+0x10/0x20 [nfs] kernel: rpc_free_task+0x30/0x70 [sunrpc] kernel: rpc_async_release+0x12/0x20 [sunrpc] kernel: process_one_work+0x174/0x390 kernel: worker_thread+0x4f/0x3e0 kernel: kthread+0x102/0x140 kernel: ? drain_workqueue+0x130/0x130 kernel: ? kthread_stop+0x110/0x110 kernel: ret_from_fork+0x35/0x40 kernel: ---[ end trace 01341980905412c9 ]---
Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Santosh Shilimkar santosh.shilimkar@oracle.com
[forward-ported to v4.20] Signed-off-by: Calum Mackay calum.mackay@oracle.com Reviewed-by: Dave Kleikamp dave.kleikamp@oracle.com Reviewed-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/direct.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 1ab91124a93e..53f0012ace42 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -98,8 +98,11 @@ struct nfs_direct_req { struct pnfs_ds_commit_info ds_cinfo; /* Storage for cinfo */ struct work_struct work; int flags; + /* for write */ #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */ #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */ + /* for read */ +#define NFS_ODIRECT_SHOULD_DIRTY (3) /* dirty user-space page after read */ struct nfs_writeverf verf; /* unstable write verifier */ };
@@ -422,7 +425,8 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr) struct nfs_page *req = nfs_list_entry(hdr->pages.next); struct page *page = req->wb_page;
- if (!PageCompound(page) && bytes < hdr->good_bytes) + if (!PageCompound(page) && bytes < hdr->good_bytes && + (dreq->flags == NFS_ODIRECT_SHOULD_DIRTY)) set_page_dirty(page); bytes += req->wb_bytes; nfs_list_remove_request(req); @@ -597,6 +601,9 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter) if (!is_sync_kiocb(iocb)) dreq->iocb = iocb;
+ if (iter_is_iovec(iter)) + dreq->flags = NFS_ODIRECT_SHOULD_DIRTY; + nfs_start_io_direct(inode);
NFS_I(inode)->read_io += count;