Merge pull request #35453 from cpuguy83/update_fsnotify

Update fsnotify to fix deadlock in removing watch

vendor.conf

@@ -85,7 +85,7 @@ github.com/philhofer/fwd 98c11a7a6ec829d672b03833c3d69a7fae1ca972
 github.com/tinylib/msgp 75ee40d2601edf122ef667e2a07d600d4c44490c
 
 # fsnotify
-github.com/fsnotify/fsnotify v1.4.2
+github.com/fsnotify/fsnotify 4da3e2cfbabc9f751898f250b49f2439785783a1
 
 # awslogs deps
 github.com/aws/aws-sdk-go v1.4.22

vendor/github.com/fsnotify/fsnotify/README.md

@@ -8,14 +8,14 @@ fsnotify utilizes [golang.org/x/sys](https://godoc.org/golang.org/x/sys) rather
 go get -u golang.org/x/sys/...
 ```
 
-Cross platform: Windows, Linux, BSD and OS X.
+Cross platform: Windows, Linux, BSD and macOS.
 
 |Adapter   |OS        |Status    |
 |----------|----------|----------|
 |inotify   |Linux 2.6.27 or later, Android\*|Supported [![Build Status](https://travis-ci.org/fsnotify/fsnotify.svg?branch=master)](https://travis-ci.org/fsnotify/fsnotify)|
-|kqueue    |BSD, OS X, iOS\*|Supported [![Build Status](https://travis-ci.org/fsnotify/fsnotify.svg?branch=master)](https://travis-ci.org/fsnotify/fsnotify)|
+|kqueue    |BSD, macOS, iOS\*|Supported [![Build Status](https://travis-ci.org/fsnotify/fsnotify.svg?branch=master)](https://travis-ci.org/fsnotify/fsnotify)|
 |ReadDirectoryChangesW|Windows|Supported [![Build status](https://ci.appveyor.com/api/projects/status/ivwjubaih4r0udeh/branch/master?svg=true)](https://ci.appveyor.com/project/NathanYoungman/fsnotify/branch/master)|
-|FSEvents  |OS X          |[Planned](https://github.com/fsnotify/fsnotify/issues/11)|
+|FSEvents  |macOS         |[Planned](https://github.com/fsnotify/fsnotify/issues/11)|
 |FEN       |Solaris 11    |[In Progress](https://github.com/fsnotify/fsnotify/issues/12)|
 |fanotify  |Linux 2.6.37+ | |
 |USN Journals |Windows    |[Maybe](https://github.com/fsnotify/fsnotify/issues/53)|
@@ -23,7 +23,7 @@ Cross platform: Windows, Linux, BSD and OS X.
 
 \* Android and iOS are untested.
 
-Please see [the documentation](https://godoc.org/github.com/fsnotify/fsnotify) for usage. Consult the [Wiki](https://github.com/fsnotify/fsnotify/wiki) for the FAQ and further information.
+Please see [the documentation](https://godoc.org/github.com/fsnotify/fsnotify) and consult the [FAQ](#faq) for usage information.
 
 ## API stability
 
@@ -41,6 +41,35 @@ Please refer to [CONTRIBUTING][] before opening an issue or pull request.
 
 See [example_test.go](https://github.com/fsnotify/fsnotify/blob/master/example_test.go).
 
+## FAQ
+
+**When a file is moved to another directory is it still being watched?**
+
+No (it shouldn't be, unless you are watching where it was moved to).
+
+**When I watch a directory, are all subdirectories watched as well?**
+
+No, you must add watches for any directory you want to watch (a recursive watcher is on the roadmap [#18][]).
+
+**Do I have to watch the Error and Event channels in a separate goroutine?**
+
+As of now, yes. Looking into making this single-thread friendly (see [howeyc #7][#7])
+
+**Why am I receiving multiple events for the same file on OS X?**
+
+Spotlight indexing on OS X can result in multiple events (see [howeyc #62][#62]). A temporary workaround is to add your folder(s) to the *Spotlight Privacy settings* until we have a native FSEvents implementation (see [#11][]).
+
+**How many files can be watched at once?**
+
+There are OS-specific limits as to how many watches can be created:
+* Linux: /proc/sys/fs/inotify/max_user_watches contains the limit, reaching this limit results in a "no space left on device" error.
+* BSD / OSX: sysctl variables "kern.maxfiles" and "kern.maxfilesperproc", reaching these limits results in a "too many open files" error.
+
+[#62]: https://github.com/howeyc/fsnotify/issues/62
+[#18]: https://github.com/fsnotify/fsnotify/issues/18
+[#11]: https://github.com/fsnotify/fsnotify/issues/11
+[#7]: https://github.com/howeyc/fsnotify/issues/7
+
 [contributing]: https://github.com/fsnotify/fsnotify/blob/master/CONTRIBUTING.md
 
 ## Related Projects

vendor/github.com/fsnotify/fsnotify/fsnotify.go

@@ -9,6 +9,7 @@ package fsnotify
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 )
 
@@ -60,3 +61,6 @@ func (op Op) String() string {
 func (e Event) String() string {
 	return fmt.Sprintf("%q: %s", e.Name, e.Op.String())
 }
+
+// Common errors that can be reported by a watcher
+var ErrEventOverflow = errors.New("fsnotify queue overflow")

vendor/github.com/fsnotify/fsnotify/inotify.go

@@ -24,7 +24,6 @@ type Watcher struct {
 	Events   chan Event
 	Errors   chan error
 	mu       sync.Mutex // Map access
-	cv       *sync.Cond // sync removing on rm_watch with IN_IGNORE
 	fd       int
 	poller   *fdPoller
 	watches  map[string]*watch // Map of inotify watches (key: path)
@@ -56,7 +55,6 @@ func NewWatcher() (*Watcher, error) {
 		done:     make(chan struct{}),
 		doneResp: make(chan struct{}),
 	}
-	w.cv = sync.NewCond(&w.mu)
 
 	go w.readEvents()
 	return w, nil
@@ -103,21 +101,23 @@ func (w *Watcher) Add(name string) error {
 	var flags uint32 = agnosticEvents
 
 	w.mu.Lock()
-	watchEntry, found := w.watches[name]
-	w.mu.Unlock()
-	if found {
-		watchEntry.flags |= flags
-		flags |= unix.IN_MASK_ADD
+	defer w.mu.Unlock()
+	watchEntry := w.watches[name]
+	if watchEntry != nil {
+		flags |= watchEntry.flags | unix.IN_MASK_ADD
 	}
 	wd, errno := unix.InotifyAddWatch(w.fd, name, flags)
 	if wd == -1 {
 		return errno
 	}
 
-	w.mu.Lock()
-	w.watches[name] = &watch{wd: uint32(wd), flags: flags}
-	w.paths[wd] = name
-	w.mu.Unlock()
+	if watchEntry == nil {
+		w.watches[name] = &watch{wd: uint32(wd), flags: flags}
+		w.paths[wd] = name
+	} else {
+		watchEntry.wd = uint32(wd)
+		watchEntry.flags = flags
+	}
 
 	return nil
 }
@@ -135,6 +135,13 @@ func (w *Watcher) Remove(name string) error {
 	if !ok {
 		return fmt.Errorf("can't remove non-existent inotify watch for: %s", name)
 	}
+
+	// We successfully removed the watch if InotifyRmWatch doesn't return an
+	// error, we need to clean up our internal state to ensure it matches
+	// inotify's kernel state.
+	delete(w.paths, int(watch.wd))
+	delete(w.watches, name)
+
 	// inotify_rm_watch will return EINVAL if the file has been deleted;
 	// the inotify will already have been removed.
 	// watches and pathes are deleted in ignoreLinux() implicitly and asynchronously
@@ -152,13 +159,6 @@ func (w *Watcher) Remove(name string) error {
 		return errno
 	}
 
-	// wait until ignoreLinux() deleting maps
-	exists := true
-	for exists {
-		w.cv.Wait()
-		_, exists = w.watches[name]
-	}
-
 	return nil
 }
 
@@ -245,13 +245,31 @@ func (w *Watcher) readEvents() {
 
 			mask := uint32(raw.Mask)
 			nameLen := uint32(raw.Len)
+
+			if mask&unix.IN_Q_OVERFLOW != 0 {
+				select {
+				case w.Errors <- ErrEventOverflow:
+				case <-w.done:
+					return
+				}
+			}
+
 			// If the event happened to the watched directory or the watched file, the kernel
 			// doesn't append the filename to the event, but we would like to always fill the
 			// the "Name" field with a valid filename. We retrieve the path of the watch from
 			// the "paths" map.
 			w.mu.Lock()
-			name := w.paths[int(raw.Wd)]
+			name, ok := w.paths[int(raw.Wd)]
+			// IN_DELETE_SELF occurs when the file/directory being watched is removed.
+			// This is a sign to clean up the maps, otherwise we are no longer in sync
+			// with the inotify kernel state which has already deleted the watch
+			// automatically.
+			if ok && mask&unix.IN_DELETE_SELF == unix.IN_DELETE_SELF {
+				delete(w.paths, int(raw.Wd))
+				delete(w.watches, name)
+			}
 			w.mu.Unlock()
+
 			if nameLen > 0 {
 				// Point "bytes" at the first byte of the filename
 				bytes := (*[unix.PathMax]byte)(unsafe.Pointer(&buf[offset+unix.SizeofInotifyEvent]))
@@ -262,7 +280,7 @@ func (w *Watcher) readEvents() {
 			event := newEvent(name, mask)
 
 			// Send the events that are not ignored on the events channel
-			if !event.ignoreLinux(w, raw.Wd, mask) {
+			if !event.ignoreLinux(mask) {
 				select {
 				case w.Events <- event:
 				case <-w.done:
@@ -279,15 +297,9 @@ func (w *Watcher) readEvents() {
 // Certain types of events can be "ignored" and not sent over the Events
 // channel. Such as events marked ignore by the kernel, or MODIFY events
 // against files that do not exist.
-func (e *Event) ignoreLinux(w *Watcher, wd int32, mask uint32) bool {
+func (e *Event) ignoreLinux(mask uint32) bool {
 	// Ignore anything the inotify API says to ignore
 	if mask&unix.IN_IGNORED == unix.IN_IGNORED {
-		w.mu.Lock()
-		defer w.mu.Unlock()
-		name := w.paths[int(wd)]
-		delete(w.paths, int(wd))
-		delete(w.watches, name)
-		w.cv.Broadcast()
 		return true
 	}