github.com/keybase/client/go@v0.0.0-20240309051027-028f7c731f8b/kbfs/libfuse/reset_caches_file.go (about)

     1  // Copyright 2016 Keybase Inc. All rights reserved.
     2  // Use of this source code is governed by a BSD
     3  // license that can be found in the LICENSE file.
     4  //
     5  //go:build !windows
     6  // +build !windows
     7  
     8  package libfuse
     9  
    10  import (
    11  	"bazil.org/fuse"
    12  	"bazil.org/fuse/fs"
    13  	"github.com/keybase/client/go/kbfs/libkbfs"
    14  	"golang.org/x/net/context"
    15  )
    16  
    17  // ResetCachesFile represents a write-only file where any write of at
    18  // least one byte triggers the resetting of all data caches.  It can
    19  // be reached from any directory under the FUSE mountpoint.  Note that
    20  // it does not clear the *node* cache, which means that the
    21  // BlockPointers for existing nodes are still cached, such that
    22  // directory listings can still be implicitly cached for nodes still
    23  // being held by the kernel.
    24  type ResetCachesFile struct {
    25  	fs *FS
    26  }
    27  
    28  var _ fs.Node = (*ResetCachesFile)(nil)
    29  
    30  // Attr implements the fs.Node interface for ResetCachesFile.
    31  func (f *ResetCachesFile) Attr(ctx context.Context, a *fuse.Attr) error {
    32  	a.Size = 0
    33  	a.Mode = 0222
    34  	return nil
    35  }
    36  
    37  var _ fs.Handle = (*ResetCachesFile)(nil)
    38  
    39  var _ fs.HandleWriter = (*ResetCachesFile)(nil)
    40  
    41  // Write implements the fs.HandleWriter interface for ResetCachesFile.
    42  func (f *ResetCachesFile) Write(ctx context.Context, req *fuse.WriteRequest,
    43  	resp *fuse.WriteResponse) (err error) {
    44  	f.fs.log.CDebugf(ctx, "ResetCachesFile Write")
    45  	defer func() { err = f.fs.processError(ctx, libkbfs.WriteMode, err) }()
    46  	if len(req.Data) == 0 {
    47  		return nil
    48  	}
    49  	f.fs.config.ResetCaches()
    50  	resp.Size = len(req.Data)
    51  	return nil
    52  }