mirror of
https://github.com/rclone/rclone.git
synced 2024-11-25 09:41:44 +08:00
2b7957cc74
This stops the cache cleaner running unnecessarily and saves resources. This also helps with issue #2227 which was caused by a second mount deleting objects in the first mounts cache.
554 lines
13 KiB
Go
554 lines
13 KiB
Go
package vfs
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import (
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"os"
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"path"
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"sync"
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"sync/atomic"
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"time"
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"github.com/ncw/rclone/fs"
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"github.com/ncw/rclone/fs/log"
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"github.com/pkg/errors"
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)
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// File represents a file
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type File struct {
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inode uint64 // inode number
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size int64 // size of file - read and written with atomic int64 - must be 64 bit aligned
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d *Dir // parent directory - read only
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mu sync.Mutex // protects the following
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o fs.Object // NB o may be nil if file is being written
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leaf string // leaf name of the object
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rwOpenCount int // number of open files on this handle
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writers []Handle // writers for this file
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nwriters int32 // len(writers) which is read/updated with atomic
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readWriters int // how many RWFileHandle are open for writing
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readWriterClosing bool // is a RWFileHandle currently cosing?
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modified bool // has the cache file be modified by a RWFileHandle?
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pendingModTime time.Time // will be applied once o becomes available, i.e. after file was written
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muRW sync.Mutex // synchonize RWFileHandle.openPending(), RWFileHandle.close() and File.Remove
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}
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// newFile creates a new File
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func newFile(d *Dir, o fs.Object, leaf string) *File {
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return &File{
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d: d,
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o: o,
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leaf: leaf,
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inode: newInode(),
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}
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}
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// String converts it to printable
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func (f *File) String() string {
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if f == nil {
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return "<nil *File>"
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}
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return f.Path()
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}
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// IsFile returns true for File - satisfies Node interface
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func (f *File) IsFile() bool {
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return true
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}
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// IsDir returns false for File - satisfies Node interface
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func (f *File) IsDir() bool {
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return false
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}
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// Mode bits of the file or directory - satisfies Node interface
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func (f *File) Mode() (mode os.FileMode) {
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return f.d.vfs.Opt.FilePerms
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}
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// Name (base) of the directory - satisfies Node interface
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func (f *File) Name() (name string) {
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return f.leaf
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}
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// Path returns the full path of the file
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func (f *File) Path() string {
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return path.Join(f.d.path, f.leaf)
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}
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// Sys returns underlying data source (can be nil) - satisfies Node interface
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func (f *File) Sys() interface{} {
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return nil
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}
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// Inode returns the inode number - satisfies Node interface
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func (f *File) Inode() uint64 {
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return f.inode
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}
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// Node returns the Node assocuated with this - satisfies Noder interface
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func (f *File) Node() Node {
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return f
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}
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// rename should be called to update the internals after a rename
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func (f *File) rename(d *Dir, o fs.Object) {
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f.mu.Lock()
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f.o = o
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f.d = d
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f.leaf = path.Base(o.Remote())
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f.mu.Unlock()
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}
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// addWriter adds a write handle to the file
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func (f *File) addWriter(h Handle) {
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f.mu.Lock()
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f.writers = append(f.writers, h)
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atomic.AddInt32(&f.nwriters, 1)
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if _, ok := h.(*RWFileHandle); ok {
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f.readWriters++
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}
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f.mu.Unlock()
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}
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// delWriter removes a write handle from the file
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func (f *File) delWriter(h Handle, modifiedCacheFile bool) (lastWriterAndModified bool) {
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f.mu.Lock()
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defer f.mu.Unlock()
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var found = -1
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for i := range f.writers {
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if f.writers[i] == h {
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found = i
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break
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}
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}
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if found >= 0 {
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f.writers = append(f.writers[:found], f.writers[found+1:]...)
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atomic.AddInt32(&f.nwriters, -1)
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} else {
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fs.Debugf(f.o, "File.delWriter couldn't find handle")
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}
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if _, ok := h.(*RWFileHandle); ok {
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f.readWriters--
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}
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f.readWriterClosing = true
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if modifiedCacheFile {
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f.modified = true
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}
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lastWriterAndModified = len(f.writers) == 0 && f.modified
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if lastWriterAndModified {
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f.modified = false
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}
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return
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}
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// addRWOpen should be called by ReadWriteHandle when they have
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// actually opened the file for read or write.
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func (f *File) addRWOpen() {
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f.mu.Lock()
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f.rwOpenCount++
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f.mu.Unlock()
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}
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// delRWOpen should be called by ReadWriteHandle when they have closed
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// an actually opene file for read or write.
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func (f *File) delRWOpen() {
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f.mu.Lock()
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f.rwOpenCount--
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f.mu.Unlock()
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}
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// rwOpens returns how many active open ReadWriteHandles there are.
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// Note that file handles which are in pending open state aren't
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// counted.
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func (f *File) rwOpens() int {
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f.mu.Lock()
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defer f.mu.Unlock()
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return f.rwOpenCount
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}
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// finishWriterClose resets the readWriterClosing flag
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func (f *File) finishWriterClose() {
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f.mu.Lock()
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f.readWriterClosing = false
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f.mu.Unlock()
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}
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// activeWriters returns the number of writers on the file
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//
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// Note that we don't take the mutex here. If we do then we can get a
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// deadlock.
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func (f *File) activeWriters() int {
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return int(atomic.LoadInt32(&f.nwriters))
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}
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// ModTime returns the modified time of the file
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//
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// if NoModTime is set then it returns the mod time of the directory
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func (f *File) ModTime() (modTime time.Time) {
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f.mu.Lock()
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defer f.mu.Unlock()
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if !f.d.vfs.Opt.NoModTime {
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// if o is nil it isn't valid yet or there are writers, so return the size so far
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if f.o == nil || len(f.writers) != 0 || f.readWriterClosing {
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if !f.pendingModTime.IsZero() {
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return f.pendingModTime
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}
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} else {
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return f.o.ModTime()
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}
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}
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return f.d.modTime
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}
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// nonNegative returns 0 if i is -ve, i otherwise
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func nonNegative(i int64) int64 {
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if i >= 0 {
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return i
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}
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return 0
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}
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// Size of the file
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func (f *File) Size() int64 {
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f.mu.Lock()
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defer f.mu.Unlock()
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// if o is nil it isn't valid yet or there are writers, so return the size so far
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if f.o == nil || len(f.writers) != 0 || f.readWriterClosing {
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return atomic.LoadInt64(&f.size)
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}
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return nonNegative(f.o.Size())
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}
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// SetModTime sets the modtime for the file
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func (f *File) SetModTime(modTime time.Time) error {
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if f.d.vfs.Opt.ReadOnly {
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return EROFS
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}
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f.mu.Lock()
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defer f.mu.Unlock()
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f.pendingModTime = modTime
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// Only update the ModTime when there are no writers, setObject will do it
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if f.o != nil && len(f.writers) == 0 && !f.readWriterClosing {
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return f.applyPendingModTime()
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}
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// queue up for later, hoping f.o becomes available
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return nil
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}
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// call with the mutex held
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func (f *File) applyPendingModTime() error {
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defer func() { f.pendingModTime = time.Time{} }()
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if f.pendingModTime.IsZero() {
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return nil
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}
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if f.o == nil {
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return errors.New("Cannot apply ModTime, file object is not available")
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}
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err := f.o.SetModTime(f.pendingModTime)
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switch err {
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case nil:
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fs.Debugf(f.o, "File.applyPendingModTime OK")
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case fs.ErrorCantSetModTime, fs.ErrorCantSetModTimeWithoutDelete:
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// do nothing, in order to not break "touch somefile" if it exists already
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default:
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fs.Errorf(f, "File.applyPendingModTime error: %v", err)
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return err
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}
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return nil
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}
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// Update the size while writing
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func (f *File) setSize(n int64) {
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atomic.StoreInt64(&f.size, n)
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}
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// Update the object when written and add it to the directory
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func (f *File) setObject(o fs.Object) {
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f.mu.Lock()
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defer f.mu.Unlock()
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f.o = o
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_ = f.applyPendingModTime()
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f.d.addObject(f)
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}
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// Update the object but don't update the directory cache - for use by
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// the directory cache
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func (f *File) setObjectNoUpdate(o fs.Object) {
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f.mu.Lock()
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defer f.mu.Unlock()
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f.o = o
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}
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// Get the current fs.Object - may be nil
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func (f *File) getObject() fs.Object {
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f.mu.Lock()
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defer f.mu.Unlock()
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return f.o
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}
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// exists returns whether the file exists already
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func (f *File) exists() bool {
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f.mu.Lock()
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defer f.mu.Unlock()
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return f.o != nil
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}
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// Wait for f.o to become non nil for a short time returning it or an
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// error. Use when opening a read handle.
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//
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// Call without the mutex held
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func (f *File) waitForValidObject() (o fs.Object, err error) {
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for i := 0; i < 50; i++ {
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f.mu.Lock()
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o = f.o
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nwriters := len(f.writers)
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wclosing := f.readWriterClosing
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f.mu.Unlock()
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if o != nil {
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return o, nil
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}
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if nwriters == 0 && !wclosing {
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return nil, errors.New("can't open file - writer failed")
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}
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time.Sleep(100 * time.Millisecond)
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}
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return nil, ENOENT
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}
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// openRead open the file for read
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func (f *File) openRead() (fh *ReadFileHandle, err error) {
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// if o is nil it isn't valid yet
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_, err = f.waitForValidObject()
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if err != nil {
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return nil, err
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}
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// fs.Debugf(o, "File.openRead")
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fh, err = newReadFileHandle(f)
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if err != nil {
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fs.Errorf(f, "File.openRead failed: %v", err)
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return nil, err
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}
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return fh, nil
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}
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// openWrite open the file for write
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func (f *File) openWrite(flags int) (fh *WriteFileHandle, err error) {
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if f.d.vfs.Opt.ReadOnly {
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return nil, EROFS
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}
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// fs.Debugf(o, "File.openWrite")
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fh, err = newWriteFileHandle(f.d, f, f.Path(), flags)
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if err != nil {
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fs.Errorf(f, "File.openWrite failed: %v", err)
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return nil, err
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}
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return fh, nil
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}
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// openRW open the file for read and write using a temporay file
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//
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// It uses the open flags passed in.
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func (f *File) openRW(flags int) (fh *RWFileHandle, err error) {
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// FIXME chunked
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if flags&accessModeMask != os.O_RDONLY && f.d.vfs.Opt.ReadOnly {
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return nil, EROFS
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}
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// fs.Debugf(o, "File.openRW")
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fh, err = newRWFileHandle(f.d, f, f.Path(), flags)
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if err != nil {
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fs.Errorf(f, "File.openRW failed: %v", err)
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return nil, err
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}
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return fh, nil
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}
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// Sync the file
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//
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// Note that we don't do anything except return OK
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func (f *File) Sync() error {
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return nil
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}
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// Remove the file
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func (f *File) Remove() error {
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f.muRW.Lock()
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defer f.muRW.Unlock()
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if f.d.vfs.Opt.ReadOnly {
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return EROFS
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}
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if f.o != nil {
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err := f.o.Remove()
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if err != nil {
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fs.Errorf(f, "File.Remove file error: %v", err)
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return err
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}
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}
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// Remove the item from the directory listing
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f.d.delObject(f.Name())
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// Remove the object from the cache
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if f.d.vfs.Opt.CacheMode >= CacheModeMinimal {
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f.d.vfs.cache.remove(f.Path())
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}
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return nil
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}
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// RemoveAll the file - same as remove for files
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func (f *File) RemoveAll() error {
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return f.Remove()
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}
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// DirEntry returns the underlying fs.DirEntry - may be nil
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func (f *File) DirEntry() (entry fs.DirEntry) {
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return f.o
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}
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// Dir returns the directory this file is in
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func (f *File) Dir() *Dir {
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return f.d
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}
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// VFS returns the instance of the VFS
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func (f *File) VFS() *VFS {
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return f.d.vfs
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}
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// Open a file according to the flags provided
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//
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// O_RDONLY open the file read-only.
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// O_WRONLY open the file write-only.
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// O_RDWR open the file read-write.
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//
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// O_APPEND append data to the file when writing.
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// O_CREATE create a new file if none exists.
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// O_EXCL used with O_CREATE, file must not exist
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// O_SYNC open for synchronous I/O.
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// O_TRUNC if possible, truncate file when opene
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//
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// We ignore O_SYNC and O_EXCL
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func (f *File) Open(flags int) (fd Handle, err error) {
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defer log.Trace(f, "flags=%s", decodeOpenFlags(flags))("fd=%v, err=%v", &fd, &err)
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var (
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write bool // if set need write support
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read bool // if set need read support
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rdwrMode = flags & accessModeMask
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)
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// http://pubs.opengroup.org/onlinepubs/7908799/xsh/open.html
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// The result of using O_TRUNC with O_RDONLY is undefined.
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// Linux seems to truncate the file, but we prefer to return EINVAL
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if rdwrMode == os.O_RDONLY && flags&os.O_TRUNC != 0 {
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return nil, EINVAL
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}
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// Figure out the read/write intents
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switch {
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case rdwrMode == os.O_RDONLY:
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read = true
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case rdwrMode == os.O_WRONLY:
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write = true
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case rdwrMode == os.O_RDWR:
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read = true
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write = true
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default:
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fs.Errorf(f, "Can't figure out how to open with flags: 0x%X", flags)
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return nil, EPERM
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}
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// If append is set then set read to force openRW
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if flags&os.O_APPEND != 0 {
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read = true
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}
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// If truncate is set then set write to force openRW
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if flags&os.O_TRUNC != 0 {
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write = true
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}
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// FIXME discover if file is in cache or not?
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// Open the correct sort of handle
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CacheMode := f.d.vfs.Opt.CacheMode
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if CacheMode >= CacheModeMinimal && f.d.vfs.cache.opens(f.Path()) > 0 {
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fd, err = f.openRW(flags)
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} else if read && write {
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if CacheMode >= CacheModeMinimal {
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fd, err = f.openRW(flags)
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} else {
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// Open write only and hope the user doesn't
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// want to read. If they do they will get an
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// EPERM plus an Error log.
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fd, err = f.openWrite(flags)
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}
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} else if write {
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if CacheMode >= CacheModeWrites {
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fd, err = f.openRW(flags)
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} else {
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fd, err = f.openWrite(flags)
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}
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} else if read {
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if CacheMode >= CacheModeFull {
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fd, err = f.openRW(flags)
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} else {
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fd, err = f.openRead()
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}
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} else {
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fs.Errorf(f, "Can't figure out how to open with flags: 0x%X", flags)
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return nil, EPERM
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}
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return fd, err
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}
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// Truncate changes the size of the named file.
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func (f *File) Truncate(size int64) (err error) {
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// make a copy of fh.writers with the lock held then unlock so
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// we can call other file methods.
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f.mu.Lock()
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writers := make([]Handle, len(f.writers))
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copy(writers, f.writers)
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f.mu.Unlock()
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// FIXME: handle closing writer
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// If have writers then call truncate for each writer
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if len(writers) != 0 {
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fs.Debugf(f.o, "Truncating %d file handles", len(writers))
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for _, h := range writers {
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truncateErr := h.Truncate(size)
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if truncateErr != nil {
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err = truncateErr
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}
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}
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return err
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}
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fs.Debugf(f.o, "Truncating file")
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// Otherwise if no writers then truncate the file by opening
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// the file and truncating it.
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flags := os.O_WRONLY
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if size == 0 {
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flags |= os.O_TRUNC
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}
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fh, err := f.Open(flags)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer fs.CheckClose(fh, &err)
|
|
if size != 0 {
|
|
return fh.Truncate(size)
|
|
}
|
|
return nil
|
|
}
|