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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Timo Rothenpieler <timo@rothenpieler.org>,
	"J. Bruce Fields" <bfields@redhat.com>,
	Chuck Lever <chuck.lever@oracle.com>
Subject: [PATCH 5.11 29/31] Revert "nfsd4: a clients own opens neednt prevent delegations"
Date: Fri, 19 Mar 2021 13:19:23 +0100	[thread overview]
Message-ID: <20210319121748.147629081@linuxfoundation.org> (raw)
In-Reply-To: <20210319121747.203523570@linuxfoundation.org>

From: J. Bruce Fields <bfields@redhat.com>

commit 6ee65a773096ab3f39d9b00311ac983be5bdeb7c upstream.

This reverts commit 94415b06eb8aed13481646026dc995f04a3a534a.

That commit claimed to allow a client to get a read delegation when it
was the only writer.  Actually it allowed a client to get a read
delegation when *any* client has a write open!

The main problem is that it's depending on nfs4_clnt_odstate structures
that are actually only maintained for pnfs exports.

This causes clients to miss writes performed by other clients, even when
there have been intervening closes and opens, violating close-to-open
cache consistency.

We can do this a different way, but first we should just revert this.

I've added pynfs 4.1 test DELEG19 to test for this, as I should have
done originally!

Cc: stable@vger.kernel.org
Reported-by: Timo Rothenpieler <timo@rothenpieler.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/locks.c          |    3 --
 fs/nfsd/nfs4state.c |   54 +++++++++++++---------------------------------------
 2 files changed, 14 insertions(+), 43 deletions(-)

--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1808,9 +1808,6 @@ check_conflicting_open(struct file *filp
 
 	if (flags & FL_LAYOUT)
 		return 0;
-	if (flags & FL_DELEG)
-		/* We leave these checks to the caller. */
-		return 0;
 
 	if (arg == F_RDLCK)
 		return inode_is_open_for_write(inode) ? -EAGAIN : 0;
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4945,32 +4945,6 @@ static struct file_lock *nfs4_alloc_init
 	return fl;
 }
 
-static int nfsd4_check_conflicting_opens(struct nfs4_client *clp,
-						struct nfs4_file *fp)
-{
-	struct nfs4_clnt_odstate *co;
-	struct file *f = fp->fi_deleg_file->nf_file;
-	struct inode *ino = locks_inode(f);
-	int writes = atomic_read(&ino->i_writecount);
-
-	if (fp->fi_fds[O_WRONLY])
-		writes--;
-	if (fp->fi_fds[O_RDWR])
-		writes--;
-	WARN_ON_ONCE(writes < 0);
-	if (writes > 0)
-		return -EAGAIN;
-	spin_lock(&fp->fi_lock);
-	list_for_each_entry(co, &fp->fi_clnt_odstate, co_perfile) {
-		if (co->co_client != clp) {
-			spin_unlock(&fp->fi_lock);
-			return -EAGAIN;
-		}
-	}
-	spin_unlock(&fp->fi_lock);
-	return 0;
-}
-
 static struct nfs4_delegation *
 nfs4_set_delegation(struct nfs4_client *clp, struct svc_fh *fh,
 		    struct nfs4_file *fp, struct nfs4_clnt_odstate *odstate)
@@ -4990,12 +4964,9 @@ nfs4_set_delegation(struct nfs4_client *
 
 	nf = find_readable_file(fp);
 	if (!nf) {
-		/*
-		 * We probably could attempt another open and get a read
-		 * delegation, but for now, don't bother until the
-		 * client actually sends us one.
-		 */
-		return ERR_PTR(-EAGAIN);
+		/* We should always have a readable file here */
+		WARN_ON_ONCE(1);
+		return ERR_PTR(-EBADF);
 	}
 	spin_lock(&state_lock);
 	spin_lock(&fp->fi_lock);
@@ -5025,19 +4996,11 @@ nfs4_set_delegation(struct nfs4_client *
 	if (!fl)
 		goto out_clnt_odstate;
 
-	status = nfsd4_check_conflicting_opens(clp, fp);
-	if (status) {
-		locks_free_lock(fl);
-		goto out_clnt_odstate;
-	}
 	status = vfs_setlease(fp->fi_deleg_file->nf_file, fl->fl_type, &fl, NULL);
 	if (fl)
 		locks_free_lock(fl);
 	if (status)
 		goto out_clnt_odstate;
-	status = nfsd4_check_conflicting_opens(clp, fp);
-	if (status)
-		goto out_clnt_odstate;
 
 	spin_lock(&state_lock);
 	spin_lock(&fp->fi_lock);
@@ -5119,6 +5082,17 @@ nfs4_open_delegation(struct svc_fh *fh,
 				goto out_no_deleg;
 			if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
 				goto out_no_deleg;
+			/*
+			 * Also, if the file was opened for write or
+			 * create, there's a good chance the client's
+			 * about to write to it, resulting in an
+			 * immediate recall (since we don't support
+			 * write delegations):
+			 */
+			if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
+				goto out_no_deleg;
+			if (open->op_create == NFS4_OPEN_CREATE)
+				goto out_no_deleg;
 			break;
 		default:
 			goto out_no_deleg;



  parent reply	other threads:[~2021-03-19 12:22 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19 12:18 [PATCH 5.11 00/31] 5.11.8-rc1 review Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 01/31] io_uring: dont attempt IO reissue from the ring exit path Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 02/31] KVM: x86/mmu: Expand on the comment in kvm_vcpu_ad_need_write_protect() Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 03/31] KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML is enabled Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 04/31] mptcp: send ack for every add_addr Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 05/31] mptcp: pm: add lockdep assertions Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 06/31] mptcp: dispose initial struct socket when its subflow is closed Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 07/31] io_uring: refactor scheduling in io_cqring_wait Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 08/31] io_uring: refactor io_cqring_wait Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 09/31] io_uring: dont keep looping for more events if we cant flush overflow Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 10/31] io_uring: simplify do_read return parsing Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 11/31] io_uring: clear IOCB_WAITQ for non -EIOCBQUEUED return Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 12/31] gpiolib: Read "gpio-line-names" from a firmware node Greg Kroah-Hartman
2021-03-19 12:27   ` Marek Vasut
2021-03-19 12:36     ` Greg Kroah-Hartman
2021-03-19 12:45       ` Marek Vasut
2021-03-19 12:19 ` [PATCH 5.11 13/31] net: bonding: fix error return code of bond_neigh_init() Greg Kroah-Hartman
2021-03-19 14:12   ` Jiri Kosina
2021-03-19 14:24     ` Jiri Kosina
2021-03-19 14:29       ` Greg Kroah-Hartman
2021-03-19 14:25     ` Greg Kroah-Hartman
2021-03-19 15:14       ` Jiri Kosina
2021-03-19 12:19 ` [PATCH 5.11 14/31] regulator: pca9450: Add SD_VSEL GPIO for LDO5 Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 15/31] regulator: pca9450: Enable system reset on WDOG_B assertion Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 16/31] regulator: pca9450: Clear PRESET_EN bit to fix BUCK1/2/3 voltage setting Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 17/31] gfs2: Add common helper for holding and releasing the freeze glock Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 18/31] gfs2: move freeze glock outside the make_fs_rw and _ro functions Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 19/31] gfs2: bypass signal_our_withdraw if no journal Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 20/31] bpf: Prohibit alu ops for pointer types not defining ptr_limit Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 21/31] bpf: Fix off-by-one for area size in creating mask to left Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 22/31] bpf: Simplify alu_limit masking for pointer arithmetic Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 23/31] bpf: Add sanity check for upper ptr_limit Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 24/31] bpf, selftests: Fix up some test_verifier cases for unprivileged Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 25/31] arm64: Unconditionally set virtual cpu id registers Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 26/31] RDMA/srp: Fix support for unpopulated and unbalanced NUMA nodes Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 27/31] fuse: fix live lock in fuse_iget() Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 28/31] Revert "nfsd4: remove check_conflicting_opens warning" Greg Kroah-Hartman
2021-03-19 12:19 ` Greg Kroah-Hartman [this message]
2021-03-19 12:19 ` [PATCH 5.11 30/31] net: dsa: b53: Support setting learning on port Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 31/31] crypto: x86/aes-ni-xts - use direct calls to and 4-way stride Greg Kroah-Hartman
2021-03-19 19:38 ` [PATCH 5.11 00/31] 5.11.8-rc1 review Naresh Kamboju
2021-03-20  9:52   ` Greg Kroah-Hartman
2021-03-19 21:23 ` Guenter Roeck

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