Merge release-20200608.0-112-g0c628c315 (automated)

3 files changed, 117 insertions, 16 deletions

diff --git a/pkg/sentry/fsimpl/gofer/directory.go b/pkg/sentry/fsimpl/gofer/directory.go
index 480510b2a..5d83fe363 100644
--- a/pkg/sentry/fsimpl/gofer/directory.go
+++ b/pkg/sentry/fsimpl/gofer/directory.go
@@ -138,6 +138,7 @@ func (fd *directoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallba
 		fd.dirents = ds
 	}
 
+	d.InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
 	if d.cachedMetadataAuthoritative() {
 		d.touchAtime(fd.vfsfd.Mount())
 	}
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
index f065c4bad..0321fd384 100644
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ b/pkg/sentry/fsimpl/gofer/filesystem.go
@@ -371,6 +371,11 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir
 		}
 		parent.touchCMtime()
 		parent.dirents = nil
+		ev := linux.IN_CREATE
+		if dir {
+			ev |= linux.IN_ISDIR
+		}
+		parent.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent)
 		return nil
 	}
 	if fs.opts.interop == InteropModeShared {
@@ -400,6 +405,11 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir
 	}
 	parent.touchCMtime()
 	parent.dirents = nil
+	ev := linux.IN_CREATE
+	if dir {
+		ev |= linux.IN_ISDIR
+	}
+	parent.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent)
 	return nil
 }
 
@@ -530,6 +540,18 @@ func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir b
 			return err
 		}
 	}
+
+	// Generate inotify events for rmdir or unlink.
+	if dir {
+		parent.watches.Notify(name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent)
+	} else {
+		var cw *vfs.Watches
+		if child != nil {
+			cw = &child.watches
+		}
+		vfs.InotifyRemoveChild(cw, &parent.watches, name)
+	}
+
 	if child != nil {
 		vfsObj.CommitDeleteDentry(&child.vfsd)
 		child.setDeleted()
@@ -1018,6 +1040,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
 		}
 		childVFSFD = &fd.vfsfd
 	}
+	d.watches.Notify(name, linux.IN_CREATE, 0, vfs.PathEvent)
 	return childVFSFD, nil
 }
 
@@ -1203,6 +1226,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
 			newParent.incLinks()
 		}
 	}
+	vfs.InotifyRename(ctx, &renamed.watches, &oldParent.watches, &newParent.watches, oldName, newName, renamed.isDir())
 	return nil
 }
 
@@ -1215,12 +1239,21 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error
 func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error {
 	var ds *[]*dentry
 	fs.renameMu.RLock()
-	defer fs.renameMuRUnlockAndCheckCaching(&ds)
 	d, err := fs.resolveLocked(ctx, rp, &ds)
 	if err != nil {
+		fs.renameMuRUnlockAndCheckCaching(&ds)
+		return err
+	}
+	if err := d.setStat(ctx, rp.Credentials(), &opts.Stat, rp.Mount()); err != nil {
+		fs.renameMuRUnlockAndCheckCaching(&ds)
 		return err
 	}
-	return d.setStat(ctx, rp.Credentials(), &opts.Stat, rp.Mount())
+	fs.renameMuRUnlockAndCheckCaching(&ds)
+
+	if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 {
+		d.InotifyWithParent(ev, 0, vfs.InodeEvent)
+	}
+	return nil
 }
 
 // StatAt implements vfs.FilesystemImpl.StatAt.
@@ -1344,24 +1377,38 @@ func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt
 func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetxattrOptions) error {
 	var ds *[]*dentry
 	fs.renameMu.RLock()
-	defer fs.renameMuRUnlockAndCheckCaching(&ds)
 	d, err := fs.resolveLocked(ctx, rp, &ds)
 	if err != nil {
+		fs.renameMuRUnlockAndCheckCaching(&ds)
 		return err
 	}
-	return d.setxattr(ctx, rp.Credentials(), &opts)
+	if err := d.setxattr(ctx, rp.Credentials(), &opts); err != nil {
+		fs.renameMuRUnlockAndCheckCaching(&ds)
+		return err
+	}
+	fs.renameMuRUnlockAndCheckCaching(&ds)
+
+	d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
+	return nil
 }
 
 // RemovexattrAt implements vfs.FilesystemImpl.RemovexattrAt.
 func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) error {
 	var ds *[]*dentry
 	fs.renameMu.RLock()
-	defer fs.renameMuRUnlockAndCheckCaching(&ds)
 	d, err := fs.resolveLocked(ctx, rp, &ds)
 	if err != nil {
+		fs.renameMuRUnlockAndCheckCaching(&ds)
+		return err
+	}
+	if err := d.removexattr(ctx, rp.Credentials(), name); err != nil {
+		fs.renameMuRUnlockAndCheckCaching(&ds)
 		return err
 	}
-	return d.removexattr(ctx, rp.Credentials(), name)
+	fs.renameMuRUnlockAndCheckCaching(&ds)
+
+	d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
+	return nil
 }
 
 // PrependPath implements vfs.FilesystemImpl.PrependPath.
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index 43c8153a4..c6c284ff3 100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -665,6 +665,9 @@ type dentry struct {
 	pipe *pipe.VFSPipe
 
 	locks vfs.FileLocks
+
+	// Inotify watches for this dentry.
+	watches vfs.Watches
 }
 
 // dentryAttrMask returns a p9.AttrMask enabling all attributes used by the
@@ -947,6 +950,8 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin
 		} else {
 			atomic.StoreInt64(&d.atime, dentryTimestampFromStatx(stat.Atime))
 		}
+		// Restore mask bits that we cleared earlier.
+		stat.Mask |= linux.STATX_ATIME
 	}
 	if setLocalMtime {
 		if stat.Mtime.Nsec == linux.UTIME_NOW {
@@ -954,6 +959,8 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin
 		} else {
 			atomic.StoreInt64(&d.mtime, dentryTimestampFromStatx(stat.Mtime))
 		}
+		// Restore mask bits that we cleared earlier.
+		stat.Mask |= linux.STATX_MTIME
 	}
 	atomic.StoreInt64(&d.ctime, now)
 	if stat.Mask&linux.STATX_SIZE != 0 {
@@ -1051,15 +1058,34 @@ func (d *dentry) decRefLocked() {
 }
 
 // InotifyWithParent implements vfs.DentryImpl.InotifyWithParent.
-//
-// TODO(gvisor.dev/issue/1479): Implement inotify.
-func (d *dentry) InotifyWithParent(events uint32, cookie uint32, et vfs.EventType) {}
+func (d *dentry) InotifyWithParent(events, cookie uint32, et vfs.EventType) {
+	if d.isDir() {
+		events |= linux.IN_ISDIR
+	}
+
+	d.fs.renameMu.RLock()
+	// The ordering below is important, Linux always notifies the parent first.
+	if d.parent != nil {
+		d.parent.watches.NotifyWithExclusions(d.name, events, cookie, et, d.isDeleted())
+	}
+	d.watches.Notify("", events, cookie, et)
+	d.fs.renameMu.RUnlock()
+}
 
 // Watches implements vfs.DentryImpl.Watches.
-//
-// TODO(gvisor.dev/issue/1479): Implement inotify.
 func (d *dentry) Watches() *vfs.Watches {
-	return nil
+	return &d.watches
+}
+
+// OnZeroWatches implements vfs.DentryImpl.OnZeroWatches.
+//
+// If no watches are left on this dentry and it has no references, cache it.
+func (d *dentry) OnZeroWatches() {
+	if atomic.LoadInt64(&d.refs) == 0 {
+		d.fs.renameMu.Lock()
+		d.checkCachingLocked()
+		d.fs.renameMu.Unlock()
+	}
 }
 
 // checkCachingLocked should be called after d's reference count becomes 0 or it
@@ -1093,6 +1119,9 @@ func (d *dentry) checkCachingLocked() {
 	// Deleted and invalidated dentries with zero references are no longer
 	// reachable by path resolution and should be dropped immediately.
 	if d.vfsd.IsDead() {
+		if d.isDeleted() {
+			d.watches.HandleDeletion()
+		}
 		if d.cached {
 			d.fs.cachedDentries.Remove(d)
 			d.fs.cachedDentriesLen--
@@ -1101,6 +1130,14 @@ func (d *dentry) checkCachingLocked() {
 		d.destroyLocked()
 		return
 	}
+	// If d still has inotify watches and it is not deleted or invalidated, we
+	// cannot cache it and allow it to be evicted. Otherwise, we will lose its
+	// watches, even if a new dentry is created for the same file in the future.
+	// Note that the size of d.watches cannot concurrently transition from zero
+	// to non-zero, because adding a watch requires holding a reference on d.
+	if d.watches.Size() > 0 {
+		return
+	}
 	// If d is already cached, just move it to the front of the LRU.
 	if d.cached {
 		d.fs.cachedDentries.Remove(d)
@@ -1277,7 +1314,7 @@ func (d *dentry) userXattrSupported() bool {
 	return filetype == linux.S_IFREG || filetype == linux.S_IFDIR
 }
 
-// Preconditions: !d.isSynthetic(). d.isRegularFile() || d.isDirectory().
+// Preconditions: !d.isSynthetic(). d.isRegularFile() || d.isDir().
 func (d *dentry) ensureSharedHandle(ctx context.Context, read, write, trunc bool) error {
 	// O_TRUNC unconditionally requires us to obtain a new handle (opened with
 	// O_TRUNC).
@@ -1422,7 +1459,13 @@ func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linu
 
 // SetStat implements vfs.FileDescriptionImpl.SetStat.
 func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
-	return fd.dentry().setStat(ctx, auth.CredentialsFromContext(ctx), &opts.Stat, fd.vfsfd.Mount())
+	if err := fd.dentry().setStat(ctx, auth.CredentialsFromContext(ctx), &opts.Stat, fd.vfsfd.Mount()); err != nil {
+		return err
+	}
+	if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 {
+		fd.dentry().InotifyWithParent(ev, 0, vfs.InodeEvent)
+	}
+	return nil
 }
 
 // Listxattr implements vfs.FileDescriptionImpl.Listxattr.
@@ -1437,12 +1480,22 @@ func (fd *fileDescription) Getxattr(ctx context.Context, opts vfs.GetxattrOption
 
 // Setxattr implements vfs.FileDescriptionImpl.Setxattr.
 func (fd *fileDescription) Setxattr(ctx context.Context, opts vfs.SetxattrOptions) error {
-	return fd.dentry().setxattr(ctx, auth.CredentialsFromContext(ctx), &opts)
+	d := fd.dentry()
+	if err := d.setxattr(ctx, auth.CredentialsFromContext(ctx), &opts); err != nil {
+		return err
+	}
+	d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
+	return nil
 }
 
 // Removexattr implements vfs.FileDescriptionImpl.Removexattr.
 func (fd *fileDescription) Removexattr(ctx context.Context, name string) error {
-	return fd.dentry().removexattr(ctx, auth.CredentialsFromContext(ctx), name)
+	d := fd.dentry()
+	if err := d.removexattr(ctx, auth.CredentialsFromContext(ctx), name); err != nil {
+		return err
+	}
+	d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
+	return nil
 }
 
 // LockBSD implements vfs.FileDescriptionImpl.LockBSD.