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authorVivek Goyal <vgoyal@redhat.com>2020-08-20 01:19:47 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2020-09-10 12:39:22 +0300
commit1dd539577c42b67da796e2e758e04171bb889779 (patch)
treeec3e67b9b630f9803c9f01d8ebaabb9a9db3ea1d /fs/fuse
parent22f3787e9d95e72d1f09795f294fb010e2998f43 (diff)
downloadlinux-1dd539577c42b67da796e2e758e04171bb889779.tar.xz
virtiofs: add a mount option to enable dax
Add a mount option to allow using dax with virtio_fs. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/Kconfig13
-rw-r--r--fs/fuse/Makefile6
-rw-r--r--fs/fuse/dax.c36
-rw-r--r--fs/fuse/fuse_i.h14
-rw-r--r--fs/fuse/inode.c18
-rw-r--r--fs/fuse/virtio_fs.c81
6 files changed, 151 insertions, 17 deletions
diff --git a/fs/fuse/Kconfig b/fs/fuse/Kconfig
index 0156dc8aa646..fddd40630077 100644
--- a/fs/fuse/Kconfig
+++ b/fs/fuse/Kconfig
@@ -38,3 +38,16 @@ config VIRTIO_FS
If you want to share files between guests or with the host, answer Y
or M.
+
+config FUSE_DAX
+ bool "Virtio Filesystem Direct Host Memory Access support"
+ default y
+ depends on VIRTIO_FS
+ depends on FS_DAX
+ depends on DAX_DRIVER
+ help
+ This allows bypassing guest page cache and allows mapping host page
+ cache directly in guest address space.
+
+ If you want to allow mounting a Virtio Filesystem with the "dax"
+ option, answer Y.
diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
index 3e8cebfb59b7..8c7021fb2cd4 100644
--- a/fs/fuse/Makefile
+++ b/fs/fuse/Makefile
@@ -7,5 +7,7 @@ obj-$(CONFIG_FUSE_FS) += fuse.o
obj-$(CONFIG_CUSE) += cuse.o
obj-$(CONFIG_VIRTIO_FS) += virtiofs.o
-fuse-objs := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o
-virtiofs-y += virtio_fs.o
+fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o
+fuse-$(CONFIG_FUSE_DAX) += dax.o
+
+virtiofs-y := virtio_fs.o
diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
new file mode 100644
index 000000000000..9660d01f49a5
--- /dev/null
+++ b/fs/fuse/dax.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * dax: direct host memory access
+ * Copyright (C) 2020 Red Hat, Inc.
+ */
+
+#include "fuse_i.h"
+
+#include <linux/dax.h>
+
+struct fuse_conn_dax {
+ /* DAX device */
+ struct dax_device *dev;
+};
+
+void fuse_dax_conn_free(struct fuse_conn *fc)
+{
+ kfree(fc->dax);
+}
+
+int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev)
+{
+ struct fuse_conn_dax *fcd;
+
+ if (!dax_dev)
+ return 0;
+
+ fcd = kzalloc(sizeof(*fcd), GFP_KERNEL);
+ if (!fcd)
+ return -ENOMEM;
+
+ fcd->dev = dax_dev;
+
+ fc->dax = fcd;
+ return 0;
+}
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 30737aabd932..97af7952373a 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -483,10 +483,14 @@ struct fuse_fs_context {
bool no_control:1;
bool no_force_umount:1;
bool legacy_opts_show:1;
+ bool dax:1;
unsigned int max_read;
unsigned int blksize;
const char *subtype;
+ /* DAX device, may be NULL */
+ struct dax_device *dax_dev;
+
/* fuse_dev pointer to fill in, should contain NULL on entry */
void **fudptr;
};
@@ -755,6 +759,11 @@ struct fuse_conn {
/** List of device instances belonging to this connection */
struct list_head devices;
+
+#ifdef CONFIG_FUSE_DAX
+ /* Dax specific conn data, non-NULL if DAX is enabled */
+ struct fuse_conn_dax *dax;
+#endif
};
static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
@@ -1093,4 +1102,9 @@ unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args);
u64 fuse_get_unique(struct fuse_iqueue *fiq);
void fuse_free_conn(struct fuse_conn *fc);
+/* dax.c */
+
+int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev);
+void fuse_dax_conn_free(struct fuse_conn *fc);
+
#endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index bdae765b2d42..1780dfe063ab 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -587,6 +587,11 @@ static int fuse_show_options(struct seq_file *m, struct dentry *root)
if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
seq_printf(m, ",blksize=%lu", sb->s_blocksize);
}
+#ifdef CONFIG_FUSE_DAX
+ if (fc->dax)
+ seq_puts(m, ",dax");
+#endif
+
return 0;
}
@@ -651,6 +656,8 @@ void fuse_conn_put(struct fuse_conn *fc)
if (refcount_dec_and_test(&fc->count)) {
struct fuse_iqueue *fiq = &fc->iq;
+ if (IS_ENABLED(CONFIG_FUSE_DAX))
+ fuse_dax_conn_free(fc);
if (fiq->ops->release)
fiq->ops->release(fiq);
put_pid_ns(fc->pid_ns);
@@ -1175,11 +1182,17 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
if (sb->s_user_ns != &init_user_ns)
sb->s_xattr = fuse_no_acl_xattr_handlers;
+ if (IS_ENABLED(CONFIG_FUSE_DAX)) {
+ err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
+ if (err)
+ goto err;
+ }
+
if (ctx->fudptr) {
err = -ENOMEM;
fud = fuse_dev_alloc_install(fc);
if (!fud)
- goto err;
+ goto err_free_dax;
}
fc->dev = sb->s_dev;
@@ -1234,6 +1247,9 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
err_dev_free:
if (fud)
fuse_dev_free(fud);
+ err_free_dax:
+ if (IS_ENABLED(CONFIG_FUSE_DAX))
+ fuse_dax_conn_free(fc);
err:
return err;
}
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index f31a59f74475..e25f62276050 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -13,6 +13,7 @@
#include <linux/virtio_fs.h>
#include <linux/delay.h>
#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
#include <linux/highmem.h>
#include <linux/uio.h>
#include "fuse_i.h"
@@ -81,6 +82,44 @@ struct virtio_fs_req_work {
static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq,
struct fuse_req *req, bool in_flight);
+enum {
+ OPT_DAX,
+};
+
+static const struct fs_parameter_spec virtio_fs_parameters[] = {
+ fsparam_flag("dax", OPT_DAX),
+ {}
+};
+
+static int virtio_fs_parse_param(struct fs_context *fc,
+ struct fs_parameter *param)
+{
+ struct fs_parse_result result;
+ struct fuse_fs_context *ctx = fc->fs_private;
+ int opt;
+
+ opt = fs_parse(fc, virtio_fs_parameters, param, &result);
+ if (opt < 0)
+ return opt;
+
+ switch (opt) {
+ case OPT_DAX:
+ ctx->dax = 1;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void virtio_fs_free_fc(struct fs_context *fc)
+{
+ struct fuse_fs_context *ctx = fc->fs_private;
+
+ kfree(ctx);
+}
+
static inline struct virtio_fs_vq *vq_to_fsvq(struct virtqueue *vq)
{
struct virtio_fs *fs = vq->vdev->priv;
@@ -1219,23 +1258,27 @@ static const struct fuse_iqueue_ops virtio_fs_fiq_ops = {
.release = virtio_fs_fiq_release,
};
-static int virtio_fs_fill_super(struct super_block *sb)
+static inline void virtio_fs_ctx_set_defaults(struct fuse_fs_context *ctx)
+{
+ ctx->rootmode = S_IFDIR;
+ ctx->default_permissions = 1;
+ ctx->allow_other = 1;
+ ctx->max_read = UINT_MAX;
+ ctx->blksize = 512;
+ ctx->destroy = true;
+ ctx->no_control = true;
+ ctx->no_force_umount = true;
+}
+
+static int virtio_fs_fill_super(struct super_block *sb, struct fs_context *fsc)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
struct virtio_fs *fs = fc->iq.priv;
+ struct fuse_fs_context *ctx = fsc->fs_private;
unsigned int i;
int err;
- struct fuse_fs_context ctx = {
- .rootmode = S_IFDIR,
- .default_permissions = 1,
- .allow_other = 1,
- .max_read = UINT_MAX,
- .blksize = 512,
- .destroy = true,
- .no_control = true,
- .no_force_umount = true,
- };
+ virtio_fs_ctx_set_defaults(ctx);
mutex_lock(&virtio_fs_mutex);
/* After holding mutex, make sure virtiofs device is still there.
@@ -1259,8 +1302,10 @@ static int virtio_fs_fill_super(struct super_block *sb)
}
/* virtiofs allocates and installs its own fuse devices */
- ctx.fudptr = NULL;
- err = fuse_fill_super_common(sb, &ctx);
+ ctx->fudptr = NULL;
+ if (ctx->dax)
+ ctx->dax_dev = fs->dax_dev;
+ err = fuse_fill_super_common(sb, ctx);
if (err < 0)
goto err_free_fuse_devs;
@@ -1371,7 +1416,7 @@ static int virtio_fs_get_tree(struct fs_context *fsc)
return PTR_ERR(sb);
if (!sb->s_root) {
- err = virtio_fs_fill_super(sb);
+ err = virtio_fs_fill_super(sb, fsc);
if (err) {
deactivate_locked_super(sb);
return err;
@@ -1386,11 +1431,19 @@ static int virtio_fs_get_tree(struct fs_context *fsc)
}
static const struct fs_context_operations virtio_fs_context_ops = {
+ .free = virtio_fs_free_fc,
+ .parse_param = virtio_fs_parse_param,
.get_tree = virtio_fs_get_tree,
};
static int virtio_fs_init_fs_context(struct fs_context *fsc)
{
+ struct fuse_fs_context *ctx;
+
+ ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+ fsc->fs_private = ctx;
fsc->ops = &virtio_fs_context_ops;
return 0;
}