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aufs: add lock around mount

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Apparently there is some kind of race in aufs kernel module code,
which leads to the errors like:

[98221.158606] aufs au_xino_create2:186:dockerd[25801]: aufs.xino create err -17
[98221.162128] aufs au_xino_set:1229:dockerd[25801]: I/O Error, failed creating xino(-17).
[98362.239085] aufs au_xino_create2:186:dockerd[6348]: aufs.xino create err -17
[98362.243860] aufs au_xino_set:1229:dockerd[6348]: I/O Error, failed creating xino(-17).
[98373.775380] aufs au_xino_create:767:dockerd[27435]: open /dev/shm/aufs.xino(-17)
[98389.015640] aufs au_xino_create2:186:dockerd[26753]: aufs.xino create err -17
[98389.018776] aufs au_xino_set:1229:dockerd[26753]: I/O Error, failed creating xino(-17).
[98424.117584] aufs au_xino_create:767:dockerd[27105]: open /dev/shm/aufs.xino(-17)

So, we have to have a lock around mount syscall.

While at it, don't call the whole Unmount() on an error path, as
it leads to bogus error from auplink flush.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This commit is contained in:
Kir Kolyshkin 2019-04-22 18:34:24 +00:00
parent 5873768dbe
commit 5cd62852fa
1 changed files with 10 additions and 3 deletions
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13
daemon/graphdriver/aufs/aufs.go
View file

@ -80,6 +80,7 @@ type Driver struct {
pathCache map[string]string
naiveDiff graphdriver.DiffDriver
locker *locker.Locker
mntL sync.Mutex
}
// Init returns a new AUFS driver.
@ -597,7 +598,7 @@ func (a *Driver) Cleanup() error {
func (a *Driver) aufsMount(ro []string, rw, target, mountLabel string) (err error) {
defer func() {
if err != nil {
Unmount(target)
mount.Unmount(target)
}
}()
@ -625,7 +626,10 @@ func (a *Driver) aufsMount(ro []string, rw, target, mountLabel string) (err erro
opts += ",dirperm1"
}
data := label.FormatMountLabel(fmt.Sprintf("%s,%s", string(b[:bp]), opts), mountLabel)
if err = unix.Mount("none", target, "aufs", 0, data); err != nil {
a.mntL.Lock()
err = unix.Mount("none", target, "aufs", 0, data)
a.mntL.Unlock()
if err != nil {
err = errors.Wrap(err, "mount target="+target+" data="+data)
return
}
@ -633,7 +637,10 @@ func (a *Driver) aufsMount(ro []string, rw, target, mountLabel string) (err erro
for ; index < len(ro); index++ {
layer := fmt.Sprintf(":%s=ro+wh", ro[index])
data := label.FormatMountLabel(fmt.Sprintf("append%s", layer), mountLabel)
if err = unix.Mount("none", target, "aufs", unix.MS_REMOUNT, data); err != nil {
a.mntL.Lock()
err = unix.Mount("none", target, "aufs", unix.MS_REMOUNT, data)
a.mntL.Unlock()
if err != nil {
err = errors.Wrap(err, "mount target="+target+" flags=MS_REMOUNT data="+data)
return
}