1
0
Fork 0
mirror of https://github.com/moby/moby.git synced 2022-11-09 12:21:53 -05:00

Update fsnotify to fix deadlock in removing watch

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
This commit is contained in:
Brian Goff 2017-11-08 16:51:06 -05:00
parent a4bdb304e2
commit e8aa22645b
4 changed files with 77 additions and 32 deletions

View file

@ -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

View file

@ -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

View file

@ -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")

View file

@ -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
}