Add support for statfs()

olivefs/src/filesystem.rs

@@ -796,8 +796,39 @@ impl Filesystem for OliveFilesystem {
     }
 
     /// Get file system statistics.
-    fn statfs(&mut self, _req: &Request<'_>, _ino: u64, reply: ReplyStatfs) {
+    fn statfs(&mut self, _req: &Request<'_>, ino: u64, reply: ReplyStatfs) {
-        reply.statfs(0, 0, 0, 0, 0, 512, 255, 0);
+        let requester = self.requester.clone();
+
+        self.spawn_with_error_handler(
+            async move {
+                let vnode = VnodeId(
+                    ino.try_into()
+                        .context("Converting u64 inode to u32 VnodeId.")?,
+                );
+
+                match requester.statfs(vnode).await? {
+                    DataResponse::Success(stats) => {
+                        reply.statfs(
+                            stats.blocks,
+                            stats.bfree,
+                            stats.bavail,
+                            stats.files,
+                            stats.ffree,
+                            stats.bsize,
+                            stats.namelen,
+                            stats.frsize,
+                        );
+                    }
+                    DataResponse::Error { code, message } => {
+                        warn!("statfs(ino: {:#x?}) failed: {:?}", ino, message);
+                        reply.error(code as c_int);
+                    }
+                }
+
+                Ok(())
+            },
+            "statfs",
+        );
     }
 
     /// Set an extended attribute.

olivefs/src/requester.rs

@@ -18,7 +18,7 @@ use crate::configuration::StreamingReaderConfig;
 use crate::requester::streaming_reader::StreamingReader;
 use olivefs_common::io::read_file;
 use olivefs_common::messages::{
-    DataCommand, DataResponse, DirectoryEntry, FileMetadata, OpenMode, VnodeId,
+    DataCommand, DataResponse, DirectoryEntry, FileMetadata, FilesystemStats, OpenMode, VnodeId,
 };
 use olivefs_common::networking::{
     hello_handshake, read_bare_message, send_bare_message, ALPN_PROTOCOL,
@@ -308,4 +308,8 @@ impl Requester {
         }
         Ok(())
     }
+
+    pub async fn statfs(&self, vnode: VnodeId) -> anyhow::Result<DataResponse<FilesystemStats>> {
+        self.internal.command(&DataCommand::StatFs { vnode }).await
+    }
 }

olivefs_common/src/messages.rs

@@ -88,6 +88,21 @@ pub enum DataCommand {
         atime: Option<SystemTime>,
         mtime: Option<SystemTime>,
     },
+    StatFs {
+        vnode: VnodeId,
+    },
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub struct FilesystemStats {
+    pub blocks: u64,
+    pub bfree: u64,
+    pub bavail: u64,
+    pub files: u64,
+    pub ffree: u64,
+    pub bsize: u32,
+    pub namelen: u32,
+    pub frsize: u32,
 }
 
 pub trait DataResponseBase: Serialize + DeserializeOwned + Debug + Clone + 'static {}

olivefsd/src/server/connections.rs

@@ -126,6 +126,16 @@ pub async fn handle_command_stream(
                 )
                 .await?;
             }
+            DataCommand::StatFs { vnode } => {
+                send_bare_message(
+                    &mut tx,
+                    &file_access
+                        .statfs(vnode)
+                        .await
+                        .unwrap_or_else(error_to_response),
+                )
+                .await?;
+            }
         }
     }
 

olivefsd/src/server/file_access.rs

@@ -1,14 +1,16 @@
 use olivefs_common::error_codes;
 use olivefs_common::error_codes::{EBADFD, EFAULT, ENOENT, ENOSYS};
 use olivefs_common::messages::{
-    DataResponse, DirectoryEntry, FileKind, FileMetadata, OpenMode, VnodeId,
+    DataResponse, DirectoryEntry, FileKind, FileMetadata, FilesystemStats, OpenMode, VnodeId,
 };
 use path_absolutize::Absolutize;
 use slab::Slab;
 use std::borrow::Borrow;
 use std::collections::HashMap;
-use std::io;
+use std::ffi::CString;
 use std::io::SeekFrom;
+use std::os::unix::ffi::OsStrExt;
+use std::{io, mem};
 
 use anyhow::{anyhow, bail};
 use libc::{ELOOP, O_NOFOLLOW};
@@ -108,6 +110,29 @@ pub fn error_to_response<A>(error: anyhow::Error) -> DataResponse<A> {
     }
 }
 
+fn statfs_wrapper(path: &Path) -> anyhow::Result<FilesystemStats> {
+    let path_c = CString::new(path.as_os_str().as_bytes()).unwrap();
+
+    let stats = unsafe {
+        let mut stats: libc::statfs = mem::zeroed();
+        match libc::statfs(path_c.as_ptr(), &mut stats) {
+            0 => Ok(stats),
+            other => Err(io::Error::from_raw_os_error(other)),
+        }
+    }?;
+
+    Ok(FilesystemStats {
+        blocks: stats.f_blocks,
+        bfree: stats.f_bfree,
+        bavail: stats.f_bavail,
+        files: stats.f_files,
+        ffree: stats.f_ffree,
+        bsize: stats.f_bsize as u32,
+        namelen: stats.f_namelen as u32,
+        frsize: stats.f_frsize as u32,
+    })
+}
+
 impl FileAccess {
     /// Looks up a Vnode to a Path.
     ///
@@ -704,4 +729,13 @@ impl FileAccess {
 
         Ok(DataResponse::Success(metadata))
     }
+
+    pub async fn statfs(&self, vnode: VnodeId) -> anyhow::Result<DataResponse<FilesystemStats>> {
+        // TODO switch to the easier ones and then handle I/O errors in the callsite
+        let path = self
+            .resolve_vnode_including_follow_symlinks_safely_best_effort(vnode)
+            .await?;
+
+        statfs_wrapper(&path).map(DataResponse::Success)
+    }
 }