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From: Vivek Goyal <vgoyal@redhat.com>
To: Linux fsdevel mailing list <linux-fsdevel@vger.kernel.org>,
	Miklos Szeredi <miklos@szeredi.hu>
Cc: virtio-fs-list <virtio-fs@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: [PATCH] virtiofs: Fail dax mount if device does not support it
Date: Tue, 9 Feb 2021 17:47:54 -0500	[thread overview]
Message-ID: <20210209224754.GG3171@redhat.com> (raw)

Right now "mount -t virtiofs -o dax myfs /mnt/virtiofs" succeeds even
if filesystem deivce does not have a cache window and hence DAX can't
be supported.

This gives a false sense to user that they are using DAX with virtiofs
but fact of the matter is that they are not.

Fix this by returning error if dax can't be supported and user has asked
for it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 fs/fuse/virtio_fs.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Index: redhat-linux/fs/fuse/virtio_fs.c
===================================================================
--- redhat-linux.orig/fs/fuse/virtio_fs.c	2021-02-04 10:40:21.704370721 -0500
+++ redhat-linux/fs/fuse/virtio_fs.c	2021-02-09 15:56:45.693653979 -0500
@@ -1324,8 +1324,15 @@ static int virtio_fs_fill_super(struct s
 
 	/* virtiofs allocates and installs its own fuse devices */
 	ctx->fudptr = NULL;
-	if (ctx->dax)
+	if (ctx->dax) {
+		if (!fs->dax_dev) {
+			err = -EINVAL;
+			pr_err("virtio-fs: dax can't be enabled as filesystem"
+			       " device does not support it.\n");
+			goto err_free_fuse_devs;
+		}
 		ctx->dax_dev = fs->dax_dev;
+	}
 	err = fuse_fill_super_common(sb, ctx);
 	if (err < 0)
 		goto err_free_fuse_devs;


WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com>
To: Linux fsdevel mailing list <linux-fsdevel@vger.kernel.org>,
	Miklos Szeredi <miklos@szeredi.hu>
Cc: virtio-fs-list <virtio-fs@redhat.com>
Subject: [Virtio-fs] [PATCH] virtiofs: Fail dax mount if device does not support it
Date: Tue, 9 Feb 2021 17:47:54 -0500	[thread overview]
Message-ID: <20210209224754.GG3171@redhat.com> (raw)

Right now "mount -t virtiofs -o dax myfs /mnt/virtiofs" succeeds even
if filesystem deivce does not have a cache window and hence DAX can't
be supported.

This gives a false sense to user that they are using DAX with virtiofs
but fact of the matter is that they are not.

Fix this by returning error if dax can't be supported and user has asked
for it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 fs/fuse/virtio_fs.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Index: redhat-linux/fs/fuse/virtio_fs.c
===================================================================
--- redhat-linux.orig/fs/fuse/virtio_fs.c	2021-02-04 10:40:21.704370721 -0500
+++ redhat-linux/fs/fuse/virtio_fs.c	2021-02-09 15:56:45.693653979 -0500
@@ -1324,8 +1324,15 @@ static int virtio_fs_fill_super(struct s
 
 	/* virtiofs allocates and installs its own fuse devices */
 	ctx->fudptr = NULL;
-	if (ctx->dax)
+	if (ctx->dax) {
+		if (!fs->dax_dev) {
+			err = -EINVAL;
+			pr_err("virtio-fs: dax can't be enabled as filesystem"
+			       " device does not support it.\n");
+			goto err_free_fuse_devs;
+		}
 		ctx->dax_dev = fs->dax_dev;
+	}
 	err = fuse_fill_super_common(sb, ctx);
 	if (err < 0)
 		goto err_free_fuse_devs;


             reply	other threads:[~2021-02-09 23:58 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-09 22:47 Vivek Goyal [this message]
2021-02-09 22:47 ` [Virtio-fs] [PATCH] virtiofs: Fail dax mount if device does not support it Vivek Goyal
2021-02-10 14:58 ` Stefan Hajnoczi
2021-02-10 14:58   ` [Virtio-fs] " Stefan Hajnoczi
2021-03-05 13:34 ` Vivek Goyal
2021-03-05 13:34   ` [Virtio-fs] " Vivek Goyal
2021-03-05 14:48   ` Miklos Szeredi
2021-03-05 14:48     ` [Virtio-fs] " Miklos Szeredi

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