kernel: devfs: Add block device stat mechanism

Signed-off-by: Ian Moffett <ian@osmora.org>

3 files changed, 81 insertions, 0 deletions

diff --git a/sys/fs/devfs.c b/sys/fs/devfs.c
index 293ee0a..3bd1b11 100644
--- a/sys/fs/devfs.c
+++ b/sys/fs/devfs.c
@@ -31,6 +31,7 @@
 #include <sys/vnode.h>
 #include <sys/errno.h>
 #include <sys/stat.h>
+#include <sys/syslog.h>
 #include <sys/mount.h>
 #include <sys/device.h>
 #include <fs/devfs.h>
@@ -38,6 +39,7 @@
 #include <string.h>
 
 struct devfs_node {
+    struct devstat stat;
     char *name;
     uint8_t is_block : 1;
     mode_t mode;
@@ -180,6 +182,7 @@ static int
 devfs_read(struct vnode *vp, struct sio_txn *sio)
 {
     struct devfs_node *dnp;
+    struct devstat *statp;
     void *devsw;
 
     if ((dnp = vp->data) == NULL)
@@ -190,6 +193,9 @@ devfs_read(struct vnode *vp, struct sio_txn *sio)
     if (!dnp->is_block)
         return cdevsw_read(devsw, dnp->dev, sio);
 
+    statp = &dnp->stat;
+    ++statp->nreads;
+
     /* Block device */
     return bdevsw_read(devsw, dnp->dev, sio);
 }
@@ -198,6 +204,7 @@ static int
 devfs_write(struct vnode *vp, struct sio_txn *sio)
 {
     struct devfs_node *dnp;
+    struct devstat *statp;
     void *devsw;
 
     if ((dnp = vp->data) == NULL)
@@ -209,6 +216,9 @@ devfs_write(struct vnode *vp, struct sio_txn *sio)
         return cdevsw_write(devsw, dnp->dev, sio);
     }
 
+    statp = &dnp->stat;
+    ++statp->nwrites;
+
     /* Block device */
     return bdevsw_write(devsw, dnp->dev, sio);
 }
@@ -233,6 +243,24 @@ devfs_init(struct fs_info *fip)
     return 0;
 }
 
+int
+devfs_devstat(struct vnode *vp, struct devstat *res)
+{
+    struct devfs_node *dnp;
+
+    if ((dnp = vp->data) == NULL) {
+        return -EIO;
+    }
+
+    /* Not supported on char devices */
+    if (!dnp->is_block) {
+        return -ENOTSUP;
+    }
+
+    *res = dnp->stat;
+    return 0;
+}
+
 /*
  * Create an entry within devfs.
  *
@@ -245,6 +273,7 @@ int
 devfs_create_entry(const char *name, devmajor_t major, dev_t dev, mode_t mode)
 {
     struct devfs_node *dnp;
+    struct devstat *statp;
     size_t name_len;
 
     dnp = dynalloc(sizeof(*dnp));
@@ -258,6 +287,10 @@ devfs_create_entry(const char *name, devmajor_t major, dev_t dev, mode_t mode)
         return -ENOMEM;
     }
 
+    statp = &dnp->stat;
+    statp->nwrites = 0;
+    statp->nreads = 0;
+
     memcpy(dnp->name, name, name_len);
     dnp->name[name_len] = '\0';
     dnp->is_block = ISSET(mode, S_IFBLK) ? 1 : 0;
diff --git a/sys/include/fs/devfs.h b/sys/include/fs/devfs.h
index 012c2eb..51b0b45 100644
--- a/sys/include/fs/devfs.h
+++ b/sys/include/fs/devfs.h
@@ -33,9 +33,11 @@
 #include <sys/vnode.h>
 #include <sys/types.h>
 #include <sys/device.h>
+#include <sys/devstat.h>
 
 extern const struct vops g_devfs_vops;
 
 int devfs_create_entry(const char *name, devmajor_t major, dev_t dev, mode_t mode);
+int devfs_devstat(struct vnode *vp, struct devstat *res);
 
 #endif  /* !_FS_DEVFS_H_ */
diff --git a/sys/include/sys/devstat.h b/sys/include/sys/devstat.h
new file mode 100644
index 0000000..91af30f
--- /dev/null
+++ b/sys/include/sys/devstat.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _SYS_DEVSTAT_H_
+#define _SYS_DEVSTAT_H_
+
+#include <sys/types.h>
+
+/*
+ * Stats for block devices
+ *
+ * @nwrites: Number of writes total
+ * @nreads: Number of reads total
+ */
+struct devstat {
+    size_t nwrites;
+    size_t nreads;
+};
+
+#endif  /* !_SYS_DEVSTAT_H_ */