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From: trondmy@kernel.org
To: "J. Bruce Fields" <bfields@redhat.com>,
	Chuck Lever <chuck.lever@oracle.com>
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH 6/6] nfsd: Set PF_LOCAL_THROTTLE on local filesystems only
Date: Mon, 30 Nov 2020 16:24:55 -0500	[thread overview]
Message-ID: <20201130212455.254469-7-trondmy@kernel.org> (raw)
In-Reply-To: <20201130212455.254469-6-trondmy@kernel.org>

From: Trond Myklebust <trond.myklebust@hammerspace.com>

Don't set PF_LOCAL_THROTTLE on remote filesystems like NFS, since they
aren't expected to ever be subject to double buffering.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/export.c          |  3 ++-
 fs/nfsd/vfs.c            | 13 +++++++++++--
 include/linux/exportfs.h |  1 +
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/export.c b/fs/nfs/export.c
index 5428713af5fe..48b879cfe6e3 100644
--- a/fs/nfs/export.c
+++ b/fs/nfs/export.c
@@ -171,5 +171,6 @@ const struct export_operations nfs_export_ops = {
 	.encode_fh = nfs_encode_fh,
 	.fh_to_dentry = nfs_fh_to_dentry,
 	.get_parent = nfs_get_parent,
-	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|EXPORT_OP_CLOSE_BEFORE_UNLINK,
+	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|
+		EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS,
 };
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 79cba942087e..04937e51de56 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -978,18 +978,25 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 				__be32 *verf)
 {
 	struct file		*file = nf->nf_file;
+	struct super_block	*sb = file_inode(file)->i_sb;
 	struct svc_export	*exp;
 	struct iov_iter		iter;
 	__be32			nfserr;
 	int			host_err;
 	int			use_wgather;
 	loff_t			pos = offset;
+	unsigned long		exp_op_flags = 0;
 	unsigned int		pflags = current->flags;
 	rwf_t			flags = 0;
+	bool			restore_flags = false;
 
 	trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
 
-	if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
+	if (sb->s_export_op)
+		exp_op_flags = sb->s_export_op->flags;
+
+	if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
+	    !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
 		/*
 		 * We want throttling in balance_dirty_pages()
 		 * and shrink_inactive_list() to only consider
@@ -998,6 +1005,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 		 * the client's dirty pages or its congested queue.
 		 */
 		current->flags |= PF_LOCAL_THROTTLE;
+		restore_flags = true;
+	}
 
 	exp = fhp->fh_export;
 	use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
@@ -1049,7 +1058,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 		trace_nfsd_write_err(rqstp, fhp, offset, host_err);
 		nfserr = nfserrno(host_err);
 	}
-	if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
+	if (restore_flags)
 		current_restore_flags(pflags, PF_LOCAL_THROTTLE);
 	return nfserr;
 }
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 846df3c96730..d93e8a6737bb 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -216,6 +216,7 @@ struct export_operations {
 #define	EXPORT_OP_NOWCC			(0x1) /* don't collect v3 wcc data */
 #define	EXPORT_OP_NOSUBTREECHK		(0x2) /* no subtree checking */
 #define	EXPORT_OP_CLOSE_BEFORE_UNLINK	(0x4) /* close files before unlink */
+#define EXPORT_OP_REMOTE_FS		(0x8) /* Filesystem is remote */
 	unsigned long	flags;
 };
 
-- 
2.28.0


  reply	other threads:[~2020-11-30 21:26 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-30 21:24 [PATCH 0/6] Patches to support NFS re-exporting trondmy
2020-11-30 21:24 ` [PATCH 1/6] nfsd: add a new EXPORT_OP_NOWCC flag to struct export_operations trondmy
2020-11-30 21:24   ` [PATCH 2/6] nfsd: allow filesystems to opt out of subtree checking trondmy
2020-11-30 21:24     ` [PATCH 3/6] nfsd: close cached files prior to a REMOVE or RENAME that would replace target trondmy
2020-11-30 21:24       ` [PATCH 4/6] exportfs: Add a function to return the raw output from fh_to_dentry() trondmy
2020-11-30 21:24         ` [PATCH 5/6] nfsd: Fix up nfsd to ensure that timeout errors don't result in ESTALE trondmy
2020-11-30 21:24           ` trondmy [this message]
2020-11-30 23:05           ` J. Bruce Fields
2020-12-01  0:39             ` Trond Myklebust
2020-12-01  2:30               ` J. Bruce Fields
2020-11-30 22:59     ` [PATCH 2/6] nfsd: allow filesystems to opt out of subtree checking J. Bruce Fields
2020-11-30 22:58   ` [PATCH 1/6] nfsd: add a new EXPORT_OP_NOWCC flag to struct export_operations J. Bruce Fields
2020-12-01  0:33     ` Trond Myklebust
2020-12-01  0:45     ` Trond Myklebust
2020-12-01  2:28       ` J. Bruce Fields
2020-12-01  3:06         ` Trond Myklebust
2020-12-01  3:11           ` bfields
2020-12-01  3:16             ` Trond Myklebust
2020-12-01  3:23               ` Trond Myklebust
2020-12-01 15:19                 ` bfields
2020-12-01 15:50                   ` Trond Myklebust
2020-12-01 15:06               ` J. Bruce Fields
2020-12-01 19:46     ` J. Bruce Fields
2020-11-30 23:11   ` Chuck Lever
2020-12-01  0:49     ` Trond Myklebust
2020-12-01  0:14   ` Jeff Layton
2020-11-30 21:40 ` [PATCH 0/6] Patches to support NFS re-exporting Chuck Lever
2020-11-30 21:51   ` Trond Myklebust

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