Add negative_dentry_timeout mount option to virtiofs to caching negative
dentry on the guest side. When the host virito-fs device has an exclusive
access to the file system and the machine has enough memory, one can
specify a long time as the timeout.
This option saves ~1 second per 10,000 stat request for non-existing paths.
Signed-off-by: Keiichi Watanabe <keiichiw@xxxxxxxxxxxx>
---
Documentation/filesystems/virtiofs.rst | 4 ++++
fs/fuse/virtio_fs.c | 8 ++++++++
2 files changed, 12 insertions(+)
diff --git a/Documentation/filesystems/virtiofs.rst b/Documentation/filesystems/virtiofs.rst
index fdec5a7840f7..b045ef2223de 100644
--- a/Documentation/filesystems/virtiofs.rst
+++ b/Documentation/filesystems/virtiofs.rst
@@ -48,6 +48,10 @@ ro, rw, context, etc. Also, virtiofs has its own options.
dax[=always,never,inode]
Enable direct access for files. See :ref:`virtiofs-dax`.
+negative_dentry_timeout=N
+ Set the time in seconds to keep negative dentry cache. Same as the FUSE's
+ mount option.
+
atime behavior
^^^^^^^^^^^^^^
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 4d8d4f16c727..bbbd840510f9 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -99,11 +99,13 @@ static const struct constant_table dax_param_enums[] = {
enum {
OPT_DAX,
OPT_DAX_ENUM,
+ OPT_NEGATIVE_DENTRY_TIMEOUT,
};
static const struct fs_parameter_spec virtio_fs_parameters[] = {
fsparam_flag("dax", OPT_DAX),
fsparam_enum("dax", OPT_DAX_ENUM, dax_param_enums),
+ fsparam_u32 ("negative_dentry_timeout", OPT_NEGATIVE_DENTRY_TIMEOUT),
{}
};
@@ -125,6 +127,9 @@ static int virtio_fs_parse_param(struct fs_context *fsc,
case OPT_DAX_ENUM:
ctx->dax_mode = result.uint_32;
break;
+ case OPT_NEGATIVE_DENTRY_TIMEOUT:
+ ctx->negative_dentry_timeout = result.uint_32;
+ break;
default:
return -EINVAL;
}
@@ -1416,6 +1421,7 @@ static int virtio_fs_get_tree(struct fs_context *fsc)
struct super_block *sb;
struct fuse_conn *fc = NULL;
struct fuse_mount *fm;
+ struct fuse_fs_context *ffc;
unsigned int virtqueue_size;
int err = -EIO;
@@ -1468,6 +1474,8 @@ static int virtio_fs_get_tree(struct fs_context *fsc)
sb->s_flags |= SB_ACTIVE;
}
+ ffc = fsc->fs_private;
+ fm->negative_dentry_timeout = ffc->negative_dentry_timeout;
WARN_ON(fsc->root);
fsc->root = dget(sb->s_root);
--
2.41.0.185.g7c58973941-goog
