Apply pseudo `Path` to members of `anon_inodefs`

kernel/src/fs/epoll/file.rs

@@ -15,7 +15,7 @@ use crate::{
     fs::{
         file_handle::FileLike,
         file_table::{FdFlags, FileDesc, get_file_fast},
-        path::RESERVED_MOUNT_ID,
+        path::Path,
         pseudofs::AnonInodeFs,
         utils::{CreationFlags, Inode},
     },
@@ -47,14 +47,19 @@ pub struct EpollFile {
     // Keep this in a separate `Arc` to avoid dropping `EpollFile` in the observer callback, which
     // may cause deadlocks.
     ready: Arc<ReadySet>,
+    /// The pseudo path associated with this epoll file.
+    pseudo_path: Path,
 }
 
 impl EpollFile {
     /// Creates a new epoll file.
     pub fn new() -> Arc<Self> {
+        let pseudo_path = AnonInodeFs::new_path(|_| "anon_inode:[eventpoll]".to_string());
+
         Arc::new(Self {
             interest: Mutex::new(BTreeSet::new()),
             ready: Arc::new(ReadySet::new()),
+            pseudo_path,
         })
     }
 
@@ -270,7 +275,7 @@ impl FileLike for EpollFile {
     }
 
     fn inode(&self) -> &Arc<dyn Inode> {
-        AnonInodeFs::shared_inode()
+        self.pseudo_path.inode()
     }
 
     fn dump_proc_fdinfo(self: Arc<Self>, fd_flags: FdFlags) -> Box<dyn Display> {
@@ -288,9 +293,8 @@ impl FileLike for EpollFile {
 
                 writeln!(f, "pos:\t{}", 0)?;
                 writeln!(f, "flags:\t0{:o}", flags)?;
-                // TODO: This should be the mount ID of the pseudo filesystem.
+                writeln!(f, "mnt_id:\t{}", AnonInodeFs::mount_node().id())?;
-                writeln!(f, "mnt_id:\t{}", RESERVED_MOUNT_ID)?;
+                writeln!(f, "ino:\t{}", AnonInodeFs::shared_inode().ino())?;
-                writeln!(f, "ino:\t{}", self.inner.inode().ino())?;
                 for entry in self.inner.interest.lock().iter() {
                     writeln!(f, "{}", entry.0)?;
                 }

kernel/src/fs/notify/inotify.rs

@@ -21,7 +21,7 @@ use crate::{
         file_handle::FileLike,
         file_table::FdFlags,
         notify::{FsEventSubscriber, FsEvents},
-        path::{Path, RESERVED_MOUNT_ID},
+        path::Path,
         pseudofs::AnonInodeFs,
         utils::{AccessMode, CreationFlags, Inode, InodeExt, StatusFlags},
     },
@@ -58,6 +58,8 @@ pub struct InotifyFile {
     pollee: Pollee,
     // A weak reference to this inotify file.
     this: Weak<InotifyFile>,
+    /// The pseudo path associated with this inotify file.
+    pseudo_path: Path,
 }
 
 impl Drop for InotifyFile {
@@ -93,6 +95,8 @@ const DEFAULT_MAX_QUEUED_EVENTS: usize = 16384;
 impl InotifyFile {
     /// Creates a new inotify file.
     pub fn new(is_nonblocking: bool) -> Result<Arc<Self>> {
+        let pseudo_path = AnonInodeFs::new_path(|_| "anon_inode:inotify".to_string());
+
         Ok(Arc::new_cyclic(|weak_self| Self {
             // Allocate watch descriptors from 1.
             // Reference: <https://elixir.bootlin.com/linux/v6.17/source/fs/notify/inotify/inotify_user.c#L402>
@@ -104,6 +108,7 @@ impl InotifyFile {
             queue_capacity: DEFAULT_MAX_QUEUED_EVENTS,
             pollee: Pollee::new(),
             this: weak_self.clone(),
+            pseudo_path,
         }))
     }
 
@@ -355,7 +360,7 @@ impl FileLike for InotifyFile {
     }
 
     fn inode(&self) -> &Arc<dyn Inode> {
-        AnonInodeFs::shared_inode()
+        self.pseudo_path.inode()
     }
 
     fn dump_proc_fdinfo(self: Arc<Self>, fd_flags: FdFlags) -> Box<dyn Display> {
@@ -373,9 +378,8 @@ impl FileLike for InotifyFile {
 
                 writeln!(f, "pos:\t{}", 0)?;
                 writeln!(f, "flags:\t0{:o}", flags)?;
-                // TODO: This should be the mount ID of the pseudo filesystem.
+                writeln!(f, "mnt_id:\t{}", AnonInodeFs::mount_node().id())?;
-                writeln!(f, "mnt_id:\t{}", RESERVED_MOUNT_ID)?;
+                writeln!(f, "ino:\t{}", AnonInodeFs::shared_inode().ino())?;
-                writeln!(f, "ino:\t{}", self.inner.inode().ino())?;
 
                 for (wd, entry) in self.inner.watch_map.lock().iter() {
                     let Some(inode) = entry.inode.upgrade() else {

kernel/src/fs/path/mod.rs

@@ -5,7 +5,7 @@
 use core::time::Duration;
 
 use inherit_methods_macro::inherit_methods;
-pub use mount::{Mount, MountPropType, PerMountFlags, RESERVED_MOUNT_ID};
+pub use mount::{Mount, MountPropType, PerMountFlags};
 pub use mount_namespace::MountNamespace;
 
 use crate::{

kernel/src/fs/path/mount.rs

@@ -36,7 +36,7 @@ pub enum MountPropType {
 static ID_ALLOCATOR: Once<SpinLock<IdAlloc>> = Once::new();
 
 /// The reserved mount ID, which represents an invalid mount.
-pub static RESERVED_MOUNT_ID: usize = 0;
+static RESERVED_MOUNT_ID: usize = 0;
 
 pub(super) fn init() {
     // TODO: Make it configurable.

kernel/src/fs/pseudofs.rs

@@ -170,6 +170,15 @@ impl AnonInodeFs {
         PseudoFs::singleton(&ANON_INODEFS, "anon_inodefs", ANON_INODEFS_MAGIC)
     }
 
+    /// Creates a pseudo `Path` for the shared inode.
+    pub fn new_path(name_fn: fn(&dyn Inode) -> String) -> Path {
+        Path::new_pseudo(
+            Self::mount_node().clone(),
+            Self::shared_inode().clone(),
+            name_fn,
+        )
+    }
+
     /// Returns the pseudo mount node of the anonymous inode file system.
     pub fn mount_node() -> &'static Arc<Mount> {
         static ANON_INODEFS_MOUNT: Once<Arc<Mount>> = Once::new();

kernel/src/process/pid_file.rs

@@ -10,7 +10,7 @@ use crate::{
     fs::{
         file_handle::FileLike,
         file_table::FdFlags,
-        path::RESERVED_MOUNT_ID,
+        path::Path,
         pseudofs::AnonInodeFs,
         utils::{CreationFlags, Inode, StatusFlags},
     },
@@ -24,6 +24,8 @@ use crate::{
 pub struct PidFile {
     process: Arc<Process>,
     is_nonblocking: AtomicBool,
+    /// The pseudo path associated with this pid file.
+    pseudo_path: Path,
 }
 
 impl Debug for PidFile {
@@ -40,9 +42,12 @@ impl Debug for PidFile {
 
 impl PidFile {
     pub fn new(process: Arc<Process>, is_nonblocking: bool) -> Self {
+        let pseudo_path = AnonInodeFs::new_path(|_| "anon_inode:[pidfd]".to_string());
+
         Self {
             process,
             is_nonblocking: AtomicBool::new(is_nonblocking),
+            pseudo_path,
         }
     }
 
@@ -95,13 +100,12 @@ impl FileLike for PidFile {
     }
 
     fn inode(&self) -> &Arc<dyn Inode> {
-        AnonInodeFs::shared_inode()
+        self.pseudo_path.inode()
     }
 
     fn dump_proc_fdinfo(self: Arc<Self>, fd_flags: FdFlags) -> Box<dyn Display> {
         struct FdInfo {
             flags: u32,
-            ino: u64,
             pid: u32,
         }
 
@@ -109,9 +113,8 @@ impl FileLike for PidFile {
             fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
                 writeln!(f, "pos:\t{}", 0)?;
                 writeln!(f, "flags:\t0{:o}", self.flags)?;
-                // TODO: This should be the mount ID of the pseudo filesystem.
+                writeln!(f, "mnt_id:\t{}", AnonInodeFs::mount_node().id())?;
-                writeln!(f, "mnt_id:\t{}", RESERVED_MOUNT_ID)?;
+                writeln!(f, "ino:\t{}", AnonInodeFs::shared_inode().ino())?;
-                writeln!(f, "ino:\t{}", self.ino)?;
                 writeln!(f, "Pid:\t{}", self.pid)?;
                 // TODO: Currently we do not support PID namespaces. Just print the PID once.
                 writeln!(f, "NSpid:\t{}", self.pid)
@@ -125,7 +128,6 @@ impl FileLike for PidFile {
 
         Box::new(FdInfo {
             flags,
-            ino: self.inode().ino(),
             pid: self.process.pid(),
         })
     }

kernel/src/syscall/eventfd.rs

@@ -24,7 +24,7 @@ use crate::{
     fs::{
         file_handle::FileLike,
         file_table::{FdFlags, FileDesc},
-        path::RESERVED_MOUNT_ID,
+        path::Path,
         pseudofs::AnonInodeFs,
         utils::{CreationFlags, Inode, StatusFlags},
     },
@@ -76,6 +76,8 @@ struct EventFile {
     pollee: Pollee,
     flags: Mutex<Flags>,
     write_wait_queue: WaitQueue,
+    /// The pseudo path associated with this eventfd file.
+    pseudo_path: Path,
 }
 
 impl EventFile {
@@ -85,11 +87,13 @@ impl EventFile {
         let counter = Mutex::new(init_val);
         let pollee = Pollee::new();
         let write_wait_queue = WaitQueue::new();
+        let pseudo_path = AnonInodeFs::new_path(|_| "anon_inode:[eventfd]".to_string());
         Self {
             counter,
             pollee,
             flags: Mutex::new(flags),
             write_wait_queue,
+            pseudo_path,
         }
     }
 
@@ -232,7 +236,7 @@ impl FileLike for EventFile {
     }
 
     fn inode(&self) -> &Arc<dyn Inode> {
-        AnonInodeFs::shared_inode()
+        self.pseudo_path.inode()
     }
 
     fn dump_proc_fdinfo(self: Arc<Self>, fd_flags: FdFlags) -> Box<dyn Display> {
@@ -250,9 +254,8 @@ impl FileLike for EventFile {
 
                 writeln!(f, "pos:\t{}", 0)?;
                 writeln!(f, "flags:\t0{:o}", flags)?;
-                // TODO: This should be the mount ID of the pseudo filesystem.
+                writeln!(f, "mnt_id:\t{}", AnonInodeFs::mount_node().id())?;
-                writeln!(f, "mnt_id:\t{}", RESERVED_MOUNT_ID)?;
+                writeln!(f, "ino:\t{}", AnonInodeFs::shared_inode().ino())?;
-                writeln!(f, "ino:\t{}", self.inner.inode().ino())?;
                 writeln!(f, "eventfd-count: {:16x}", *self.inner.counter.lock())
             }
         }

kernel/src/syscall/signalfd.rs

@@ -20,7 +20,7 @@ use crate::{
     fs::{
         file_handle::FileLike,
         file_table::{FdFlags, FileDesc, get_file_fast},
-        path::RESERVED_MOUNT_ID,
+        path::Path,
         pseudofs::AnonInodeFs,
         utils::{CreationFlags, Inode, StatusFlags},
     },
@@ -139,14 +139,19 @@ struct SignalFile {
     signals_mask: AtomicSigMask,
     /// Non-blocking mode flag
     non_blocking: AtomicBool,
+    /// The pseudo path associated with this signalfd file.
+    pseudo_path: Path,
 }
 
 impl SignalFile {
     /// Create a new signalfd instance
     fn new(mask: AtomicSigMask, non_blocking: bool) -> Self {
+        let pseudo_path = AnonInodeFs::new_path(|_| "anon_inode:[signalfd]".to_string());
+
         Self {
             signals_mask: mask,
             non_blocking: AtomicBool::new(non_blocking),
+            pseudo_path,
         }
     }
 
@@ -264,13 +269,12 @@ impl FileLike for SignalFile {
     }
 
     fn inode(&self) -> &Arc<dyn Inode> {
-        AnonInodeFs::shared_inode()
+        self.pseudo_path.inode()
     }
 
     fn dump_proc_fdinfo(self: Arc<Self>, fd_flags: FdFlags) -> Box<dyn Display> {
         struct FdInfo {
             flags: u32,
-            ino: u64,
             sigmask: u64,
         }
 
@@ -278,9 +282,8 @@ impl FileLike for SignalFile {
             fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
                 writeln!(f, "pos:\t{}", 0)?;
                 writeln!(f, "flags:\t0{:o}", self.flags)?;
-                // TODO: This should be the mount ID of the pseudo filesystem.
+                writeln!(f, "mnt_id:\t{}", AnonInodeFs::mount_node().id())?;
-                writeln!(f, "mnt_id:\t{}", RESERVED_MOUNT_ID)?;
+                writeln!(f, "ino:\t{}", AnonInodeFs::shared_inode().ino())?;
-                writeln!(f, "ino:\t{}", self.ino)?;
                 writeln!(f, "sigmask:\t{:016x}", self.sigmask)
             }
         }
@@ -292,7 +295,6 @@ impl FileLike for SignalFile {
 
         Box::new(FdInfo {
             flags,
-            ino: self.inode().ino(),
             sigmask: self.mask().load(Ordering::Relaxed).into(),
         })
     }

kernel/src/time/timerfd.rs

@@ -14,7 +14,7 @@ use crate::{
     fs::{
         file_handle::FileLike,
         file_table::FdFlags,
-        path::RESERVED_MOUNT_ID,
+        path::Path,
         pseudofs::AnonInodeFs,
         utils::{CreationFlags, Inode, StatusFlags},
     },
@@ -35,6 +35,8 @@ pub struct TimerfdFile {
     pollee: Pollee,
     flags: AtomicTFDFlags,
     settime_flags: AtomicTFDSetTimeFlags,
+    /// The pseudo path associated with this timerfd file.
+    pseudo_path: Path,
 }
 
 bitflags! {
@@ -115,6 +117,8 @@ impl TimerfdFile {
             create_timer(clockid, expired_fn, ctx)
         }?;
 
+        let pseudo_path = AnonInodeFs::new_path(|_| "anon_inode:[timerfd]".to_string());
+
         Ok(TimerfdFile {
             clockid,
             timer,
@@ -122,6 +126,7 @@ impl TimerfdFile {
             pollee,
             flags: AtomicTFDFlags::new(flags),
             settime_flags: AtomicTFDSetTimeFlags::default(),
+            pseudo_path,
         })
     }
 
@@ -252,13 +257,12 @@ impl FileLike for TimerfdFile {
     }
 
     fn inode(&self) -> &Arc<dyn Inode> {
-        AnonInodeFs::shared_inode()
+        self.pseudo_path.inode()
     }
 
     fn dump_proc_fdinfo(self: Arc<Self>, fd_flags: FdFlags) -> Box<dyn Display> {
         struct FdInfo {
             flags: u32,
-            ino: u64,
             clockid: i32,
             ticks: u64,
             settime_flags: u32,
@@ -270,9 +274,8 @@ impl FileLike for TimerfdFile {
             fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
                 writeln!(f, "pos:\t{}", 0)?;
                 writeln!(f, "flags:\t0{:o}", self.flags)?;
-                // TODO: This should be the mount ID of the pseudo filesystem.
+                writeln!(f, "mnt_id:\t{}", AnonInodeFs::mount_node().id())?;
-                writeln!(f, "mnt_id:\t{}", RESERVED_MOUNT_ID)?;
+                writeln!(f, "ino:\t{}", AnonInodeFs::shared_inode().ino())?;
-                writeln!(f, "ino:\t{}", self.ino)?;
                 writeln!(f, "clockid: {}", self.clockid)?;
                 writeln!(f, "ticks: {}", self.ticks)?;
                 writeln!(f, "settime flags: 0{:o}", self.settime_flags)?;
@@ -299,7 +302,6 @@ impl FileLike for TimerfdFile {
         let timer_guard = self.timer.lock();
         Box::new(FdInfo {
             flags,
-            ino: self.inode().ino(),
             clockid: self.clockid,
             ticks: self.ticks.load(Ordering::Relaxed),
             settime_flags: self.settime_flags.load(Ordering::Relaxed).bits(),