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Subject[PATCH 08/20] fuse,virtiofs: Add a mount option to enable dax
Date
Add a mount option to allow using dax with virtio_fs.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
fs/fuse/fuse_i.h | 7 ++++
fs/fuse/inode.c | 3 ++
fs/fuse/virtio_fs.c | 82 +++++++++++++++++++++++++++++++++++++--------
3 files changed, 78 insertions(+), 14 deletions(-)

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 2cebdf6dcfd8..1fe5065a2902 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -483,10 +483,14 @@ struct fuse_fs_context {
bool destroy:1;
bool no_control:1;
bool no_force_umount: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;
};
@@ -758,6 +762,9 @@ struct fuse_conn {

/** List of device instances belonging to this connection */
struct list_head devices;
+
+ /** DAX device, non-NULL if DAX is supported */
+ struct dax_device *dax_dev;
};

static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index f160a3d47b63..84295fac4ff3 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -569,6 +569,8 @@ static int fuse_show_options(struct seq_file *m, struct dentry *root)
seq_printf(m, ",max_read=%u", fc->max_read);
if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
seq_printf(m, ",blksize=%lu", sb->s_blocksize);
+ if (fc->dax_dev)
+ seq_printf(m, ",dax");
return 0;
}

@@ -1185,6 +1187,7 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
fc->destroy = ctx->destroy;
fc->no_control = ctx->no_control;
fc->no_force_umount = ctx->no_force_umount;
+ fc->dax_dev = ctx->dax_dev;

err = -ENOMEM;
root = fuse_get_root_inode(sb, ctx->rootmode);
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 3f786a15b0d9..62cdd6817b5b 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -10,6 +10,7 @@
#include <linux/virtio_fs.h>
#include <linux/delay.h>
#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
#include <linux/highmem.h>
#include "fuse_i.h"

@@ -65,6 +66,45 @@ struct virtio_fs_forget {
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;
+
+ if (ctx)
+ kfree(ctx);
+}
+
static inline struct virtio_fs_vq *vq_to_fsvq(struct virtqueue *vq)
{
struct virtio_fs *fs = vq->vdev->priv;
@@ -1045,23 +1085,27 @@ 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.
@@ -1084,8 +1128,10 @@ static int virtio_fs_fill_super(struct super_block *sb)
goto err_free_fuse_devs;
}

- ctx.fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
- err = fuse_fill_super_common(sb, &ctx);
+ ctx->fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
+ if (ctx->dax)
+ ctx->dax_dev = fs->dax_dev;
+ err = fuse_fill_super_common(sb, ctx);
if (err < 0)
goto err_free_fuse_devs;

@@ -1200,7 +1246,7 @@ 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;
@@ -1215,11 +1261,19 @@ 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;
}
--
2.20.1
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