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Preserve extra overlayfs mount options when loading many-layered images #1156

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merged 1 commit into from
Feb 28, 2022
Merged

Preserve extra overlayfs mount options when loading many-layered images #1156

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40 changes: 22 additions & 18 deletions drivers/overlay/overlay.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1462,41 +1462,37 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO

workdir := path.Join(dir, "work")

var opts string
if readWrite {
opts = fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", strings.Join(absLowers, ":"), diffDir, workdir)
} else {
opts = fmt.Sprintf("lowerdir=%s:%s", diffDir, strings.Join(absLowers, ":"))
}
if len(optsList) > 0 {
opts = fmt.Sprintf("%s,%s", strings.Join(optsList, ","), opts)
}

if d.options.mountProgram == "" && unshare.IsRootless() {
opts = fmt.Sprintf("%s,userxattr", opts)
optsList = append(optsList, "userxattr")
}

// If "volatile" is not supported by the file system, just ignore the request
if options.Volatile && !hasVolatileOption(strings.Split(opts, ",")) {
if options.Volatile && !hasVolatileOption(optsList) {
supported, err := d.getSupportsVolatile()
if err != nil {
return "", err
}
// If "volatile" is not supported by the file system, just ignore the request
if supported {
opts = fmt.Sprintf("%s,volatile", opts)
optsList = append(optsList, "volatile")
}
}

var opts string
if readWrite {
opts = fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", strings.Join(absLowers, ":"), diffDir, workdir)
} else {
opts = fmt.Sprintf("lowerdir=%s:%s", diffDir, strings.Join(absLowers, ":"))
}
if len(optsList) > 0 {
opts = fmt.Sprintf("%s,%s", opts, strings.Join(optsList, ","))
}

mountData := label.FormatMountLabel(opts, options.MountLabel)
mountFunc := unix.Mount
mountTarget := mergedDir

pageSize := unix.Getpagesize()

// Use relative paths and mountFrom when the mount data has exceeded
// the page size. The mount syscall fails if the mount data cannot
// fit within a page and relative links make the mount data much
// smaller at the expense of requiring a fork exec to chroot.
if d.options.mountProgram != "" {
mountFunc = func(source string, target string, mType string, flags uintptr, label string) error {
if !disableShifting {
Expand All @@ -1523,6 +1519,11 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
return nil
}
} else if len(mountData) > pageSize {
// Use relative paths and mountFrom when the mount data has exceeded
// the page size. The mount syscall fails if the mount data cannot
// fit within a page and relative links make the mount data much
// smaller at the expense of requiring a fork exec to chroot.

workdir = path.Join(id, "work")
//FIXME: We need to figure out to get this to work with additional stores
if readWrite {
Expand All @@ -1531,6 +1532,9 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
} else {
opts = fmt.Sprintf("lowerdir=%s", strings.Join(absLowers, ":"))
}
if len(optsList) > 0 {
opts = fmt.Sprintf("%s,%s", opts, strings.Join(optsList, ","))
}
Comment on lines +1535 to +1537
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This part is the fix. The rest of the patch is just supporting changes for this line.

mountData = label.FormatMountLabel(opts, options.MountLabel)
if len(mountData) > pageSize {
return "", fmt.Errorf("cannot mount layer, mount label %q too large %d > page size %d", options.MountLabel, len(mountData), pageSize)
Expand Down