rclone/vfs/vfscache/cache_test.go
Leo Luan c665201b85 vfs: support synchronous cache space recovery upon ENOSPC
This patch provides the support of synchronous cache space recovery
to allow read threads to recover from ENOSPC errors when cache space
can be recovered from cache items that are not in use or safe to be
reset/emptied .

The patch complements the existing cache cleaning process in two ways.

Firstly, the existing cache cleaning process is time-driven that runs
periodically. The cache space can run out while the cache cleaner
thread is still waiting for its next scheduled run. The io threads
encountering ENOSPC return an internal error to the applications
in this case even when cache space can be recovered to avoid this
error. This patch addresses this problem by having the read threads
kick the cache cleaner thread in this condition to recover cache
space preventing unnecessary ENOSPC errors from being seen by the
applications.

Secondly, this patch enhances the cache cleaner to support cache
item reset. Currently the cache purge process removes cache
items that are not in use. This may not be sufficient when the
total size of the working set exceeds the cache directory's
capacity. Like in the current code, this patch starts the purge
process by removing cache files that are not in use. Cache items
whose access times are older than vfs-cache-max-age are removed first.
After that, other not-in-use items are removed in LRU order until
vfs-cache-max-size is reached. If the vfs-cache-max-size (the quota)
is still not reached at this time, this patch adds a cache reset
step to reset/empty cache files that are still in use but not
dirtied.  This enables application processes to continue without
seeing an error even when the working set depletes the cache space
as long as there is not a large write working set hoarding the
entire cache space.

By design this patch does not add ENOSPC error recovery for write
IOs. Rclone does not empty a write cache item until the file data
is written back to the backend upon close. Allowing more cache
space to be consumed by dirty cache items when the cache space is
already running low would increase the risk of exhausting the cache
space in a way that the vfs mount becomes unreadable.
2020-08-25 21:12:06 +01:00

703 lines
17 KiB
Go

package vfscache
import (
"context"
"fmt"
"os"
"path/filepath"
"sort"
"testing"
"time"
_ "github.com/rclone/rclone/backend/local" // import the local backend
"github.com/rclone/rclone/fstest"
"github.com/rclone/rclone/vfs/vfscommon"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
// TestMain drives the tests
func TestMain(m *testing.M) {
fstest.TestMain(m)
}
// convert c.item to a string
func itemAsString(c *Cache) []string {
c.mu.Lock()
defer c.mu.Unlock()
var out []string
for name, item := range c.item {
out = append(out, fmt.Sprintf("name=%q opens=%d size=%d", filepath.ToSlash(name), item.opens, item.info.Size))
}
sort.Strings(out)
return out
}
// convert c.item to a string
func itemSpaceAsString(c *Cache) []string {
c.mu.Lock()
defer c.mu.Unlock()
var out []string
for name, item := range c.item {
space := item.info.Rs.Size()
out = append(out, fmt.Sprintf("name=%q opens=%d size=%d space=%d", filepath.ToSlash(name), item.opens, item.info.Size, space))
}
sort.Strings(out)
return out
}
// open an item and write to it
func itemWrite(t *testing.T, item *Item, contents string) {
require.NoError(t, item.Open(nil))
_, err := item.WriteAt([]byte(contents), 0)
require.NoError(t, err)
}
func assertPathNotExist(t *testing.T, path string) {
_, err := os.Stat(path)
assert.True(t, os.IsNotExist(err))
}
func assertPathExist(t *testing.T, path string) os.FileInfo {
fi, err := os.Stat(path)
assert.NoError(t, err)
return fi
}
type avInfo struct {
Remote string
Size int64
IsDir bool
}
var avInfos []avInfo
func addVirtual(remote string, size int64, isDir bool) error {
avInfos = append(avInfos, avInfo{
Remote: remote,
Size: size,
IsDir: isDir,
})
return nil
}
func newTestCacheOpt(t *testing.T, opt vfscommon.Options) (r *fstest.Run, c *Cache, cleanup func()) {
r = fstest.NewRun(t)
ctx, cancel := context.WithCancel(context.Background())
avInfos = nil
c, err := New(ctx, r.Fremote, &opt, addVirtual)
require.NoError(t, err)
cleanup = func() {
err := c.CleanUp()
require.NoError(t, err)
assertPathNotExist(t, c.root)
cancel()
r.Finalise()
}
return r, c, cleanup
}
func newTestCache(t *testing.T) (r *fstest.Run, c *Cache, cleanup func()) {
opt := vfscommon.DefaultOpt
// Disable the cache cleaner as it interferes with these tests
opt.CachePollInterval = 0
// Disable synchronous write
opt.WriteBack = 0
return newTestCacheOpt(t, opt)
}
func TestCacheNew(t *testing.T) {
r, c, cleanup := newTestCache(t)
defer cleanup()
assert.Contains(t, c.root, "vfs")
assert.Contains(t, c.fcache.Root(), filepath.Base(r.Fremote.Root()))
assert.Equal(t, []string(nil), itemAsString(c))
// mkdir
p, err := c.mkdir("potato")
require.NoError(t, err)
assert.Equal(t, "potato", filepath.Base(p))
assert.Equal(t, []string(nil), itemAsString(c))
fi := assertPathExist(t, filepath.Dir(p))
assert.True(t, fi.IsDir())
// get
item, _ := c.get("potato")
item2, _ := c.get("potato")
assert.Equal(t, item, item2)
assert.WithinDuration(t, time.Now(), item.info.ATime, time.Second)
// open
assert.Equal(t, []string{
`name="potato" opens=0 size=0`,
}, itemAsString(c))
potato := c.Item("/potato")
require.NoError(t, potato.Open(nil))
assert.Equal(t, []string{
`name="potato" opens=1 size=0`,
}, itemAsString(c))
assert.WithinDuration(t, time.Now(), potato.info.ATime, time.Second)
assert.Equal(t, 1, potato.opens)
// write the file
require.NoError(t, potato.Truncate(5))
atime := time.Now()
potato.info.ATime = atime
assert.Equal(t, []string{
`name="potato" opens=1 size=5`,
}, itemAsString(c))
assert.True(t, atime.Equal(potato.info.ATime), fmt.Sprintf("%v != %v", atime, potato.info.ATime))
// try purging with file open
c.purgeOld(10 * time.Second)
assertPathExist(t, p)
// close
assert.Equal(t, []string{
`name="potato" opens=1 size=5`,
}, itemAsString(c))
require.NoError(t, potato.Truncate(6))
assert.Equal(t, []string{
`name="potato" opens=1 size=6`,
}, itemAsString(c))
require.NoError(t, potato.Close(nil))
assert.Equal(t, []string{
`name="potato" opens=0 size=6`,
}, itemAsString(c))
item, _ = c.get("potato")
assert.WithinDuration(t, time.Now(), item.info.ATime, time.Second)
assert.Equal(t, 0, item.opens)
// try purging with file closed
c.purgeOld(10 * time.Second)
assertPathExist(t, p)
//.. purge again with -ve age
c.purgeOld(-10 * time.Second)
assertPathNotExist(t, p)
// clean - have tested the internals already
c.clean(false)
}
func TestCacheOpens(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
assert.Equal(t, []string(nil), itemAsString(c))
potato := c.Item("potato")
require.NoError(t, potato.Open(nil))
assert.Equal(t, []string{
`name="potato" opens=1 size=0`,
}, itemAsString(c))
require.NoError(t, potato.Open(nil))
assert.Equal(t, []string{
`name="potato" opens=2 size=0`,
}, itemAsString(c))
require.NoError(t, potato.Close(nil))
assert.Equal(t, []string{
`name="potato" opens=1 size=0`,
}, itemAsString(c))
require.NoError(t, potato.Close(nil))
assert.Equal(t, []string{
`name="potato" opens=0 size=0`,
}, itemAsString(c))
require.NoError(t, potato.Open(nil))
a1 := c.Item("a//b/c/d/one")
a2 := c.Item("a/b/c/d/e/two")
a3 := c.Item("a/b/c/d/e/f/three")
require.NoError(t, a1.Open(nil))
require.NoError(t, a2.Open(nil))
require.NoError(t, a3.Open(nil))
assert.Equal(t, []string{
`name="a/b/c/d/e/f/three" opens=1 size=0`,
`name="a/b/c/d/e/two" opens=1 size=0`,
`name="a/b/c/d/one" opens=1 size=0`,
`name="potato" opens=1 size=0`,
}, itemAsString(c))
require.NoError(t, potato.Close(nil))
require.NoError(t, a1.Close(nil))
require.NoError(t, a2.Close(nil))
require.NoError(t, a3.Close(nil))
assert.Equal(t, []string{
`name="a/b/c/d/e/f/three" opens=0 size=0`,
`name="a/b/c/d/e/two" opens=0 size=0`,
`name="a/b/c/d/one" opens=0 size=0`,
`name="potato" opens=0 size=0`,
}, itemAsString(c))
}
// test the open, mkdir, purge, close, purge sequence
func TestCacheOpenMkdir(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
// open
potato := c.Item("sub/potato")
require.NoError(t, potato.Open(nil))
assert.Equal(t, []string{
`name="sub/potato" opens=1 size=0`,
}, itemAsString(c))
// mkdir
p, err := c.mkdir("sub/potato")
require.NoError(t, err)
assert.Equal(t, "potato", filepath.Base(p))
assert.Equal(t, []string{
`name="sub/potato" opens=1 size=0`,
}, itemAsString(c))
// test directory exists
fi := assertPathExist(t, filepath.Dir(p))
assert.True(t, fi.IsDir())
// clean the cache
c.purgeOld(-10 * time.Second)
// test directory still exists
fi = assertPathExist(t, filepath.Dir(p))
assert.True(t, fi.IsDir())
// close
require.NoError(t, potato.Close(nil))
assert.Equal(t, []string{
`name="sub/potato" opens=0 size=0`,
}, itemAsString(c))
// clean the cache
c.purgeOld(-10 * time.Second)
c.purgeEmptyDirs()
assert.Equal(t, []string(nil), itemAsString(c))
// test directory does not exist
assertPathNotExist(t, filepath.Dir(p))
}
func TestCachePurgeOld(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
// Test funcs
c.purgeOld(-10 * time.Second)
potato2 := c.Item("sub/dir2/potato2")
require.NoError(t, potato2.Open(nil))
potato := c.Item("sub/dir/potato")
require.NoError(t, potato.Open(nil))
require.NoError(t, potato2.Close(nil))
require.NoError(t, potato.Open(nil))
assert.Equal(t, []string{
`name="sub/dir/potato" opens=2 size=0`,
`name="sub/dir2/potato2" opens=0 size=0`,
}, itemAsString(c))
c.purgeOld(-10 * time.Second)
assert.Equal(t, []string{
`name="sub/dir/potato" opens=2 size=0`,
}, itemAsString(c))
require.NoError(t, potato.Close(nil))
assert.Equal(t, []string{
`name="sub/dir/potato" opens=1 size=0`,
}, itemAsString(c))
c.purgeOld(-10 * time.Second)
assert.Equal(t, []string{
`name="sub/dir/potato" opens=1 size=0`,
}, itemAsString(c))
require.NoError(t, potato.Close(nil))
assert.Equal(t, []string{
`name="sub/dir/potato" opens=0 size=0`,
}, itemAsString(c))
c.purgeOld(10 * time.Second)
assert.Equal(t, []string{
`name="sub/dir/potato" opens=0 size=0`,
}, itemAsString(c))
c.purgeOld(-10 * time.Second)
assert.Equal(t, []string(nil), itemAsString(c))
}
func TestCachePurgeOverQuota(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
// Test funcs
// Make some test files
potato := c.Item("sub/dir/potato")
itemWrite(t, potato, "hello")
potato2 := c.Item("sub/dir2/potato2")
itemWrite(t, potato2, "hello2")
assert.Equal(t, []string{
`name="sub/dir/potato" opens=1 size=5`,
`name="sub/dir2/potato2" opens=1 size=6`,
}, itemAsString(c))
// Check nothing removed
c.purgeOverQuota(1)
// Close the files
require.NoError(t, potato.Close(nil))
require.NoError(t, potato2.Close(nil))
assert.Equal(t, []string{
`name="sub/dir/potato" opens=0 size=5`,
`name="sub/dir2/potato2" opens=0 size=6`,
}, itemAsString(c))
// Update the stats to read the total size
c.updateUsed()
// make potato2 definitely after potato
t1 := time.Now().Add(10 * time.Second)
potato2.info.ATime = t1
// Check only potato removed to get below quota
c.purgeOverQuota(10)
assert.Equal(t, int64(6), c.used)
assert.Equal(t, []string{
`name="sub/dir2/potato2" opens=0 size=6`,
}, itemAsString(c))
// Put potato back
potato = c.Item("sub/dir/potato")
require.NoError(t, potato.Open(nil))
require.NoError(t, potato.Truncate(5))
require.NoError(t, potato.Close(nil))
// Update the stats to read the total size
c.updateUsed()
assert.Equal(t, []string{
`name="sub/dir/potato" opens=0 size=5`,
`name="sub/dir2/potato2" opens=0 size=6`,
}, itemAsString(c))
// make potato definitely after potato2
t2 := t1.Add(20 * time.Second)
potato.info.ATime = t2
// Check only potato2 removed to get below quota
c.purgeOverQuota(10)
assert.Equal(t, int64(5), c.used)
c.purgeEmptyDirs()
assert.Equal(t, []string{
`name="sub/dir/potato" opens=0 size=5`,
}, itemAsString(c))
// Now purge everything
c.purgeOverQuota(1)
assert.Equal(t, int64(0), c.used)
c.purgeEmptyDirs()
assert.Equal(t, []string(nil), itemAsString(c))
// Check nothing left behind
c.clean(false)
assert.Equal(t, int64(0), c.used)
assert.Equal(t, []string(nil), itemAsString(c))
}
// test reset clean files
func TestCachePurgeClean(t *testing.T) {
r, c, cleanup := newItemTestCache(t)
defer cleanup()
contents, obj, patato1 := newFile(t, r, c, "existing")
_ = contents
// Open the object to create metadata for it
require.NoError(t, patato1.Open(obj))
require.NoError(t, patato1.Open(obj))
size, err := patato1.GetSize()
require.NoError(t, err)
assert.Equal(t, int64(100), size)
// Read something to instantiate the cache file
buf := make([]byte, 10)
_, err = patato1.ReadAt(buf, 10)
require.NoError(t, err)
// Test cache file present
_, err = os.Stat(patato1.c.toOSPath(patato1.name))
require.NoError(t, err)
// Add some potatos
potato2 := c.Item("sub/dir/potato2")
require.NoError(t, potato2.Open(nil))
require.NoError(t, potato2.Truncate(5))
potato3 := c.Item("sub/dir/potato3")
require.NoError(t, potato3.Open(nil))
require.NoError(t, potato3.Truncate(6))
c.updateUsed()
c.purgeClean(1)
assert.Equal(t, []string{
`name="existing" opens=2 size=100 space=0`,
`name="sub/dir/potato2" opens=1 size=5 space=5`,
`name="sub/dir/potato3" opens=1 size=6 space=6`,
}, itemSpaceAsString(c))
assert.Equal(t, int64(11), c.used)
require.NoError(t, potato2.Close(nil))
c.purgeClean(1)
assert.Equal(t, []string{
`name="existing" opens=2 size=100 space=0`,
`name="sub/dir/potato3" opens=1 size=6 space=6`,
}, itemSpaceAsString(c))
assert.Equal(t, int64(6), c.used)
require.NoError(t, patato1.Close(nil))
require.NoError(t, patato1.Close(nil))
require.NoError(t, potato3.Close(nil))
// Remove all files now. The are all not in use.
// purgeClean does not remove empty cache files. purgeOverQuota does.
// So we use purgeOverQuota here for the cleanup.
c.purgeOverQuota(1)
c.purgeEmptyDirs()
assert.Equal(t, []string(nil), itemAsString(c))
}
func TestCacheInUse(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
assert.False(t, c.InUse("potato"))
potato := c.Item("potato")
assert.False(t, c.InUse("potato"))
require.NoError(t, potato.Open(nil))
assert.True(t, c.InUse("potato"))
require.NoError(t, potato.Close(nil))
assert.False(t, c.InUse("potato"))
}
func TestCacheDirtyItem(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
assert.Nil(t, c.DirtyItem("potato"))
potato := c.Item("potato")
assert.Nil(t, c.DirtyItem("potato"))
require.NoError(t, potato.Open(nil))
require.NoError(t, potato.Truncate(5))
assert.Equal(t, potato, c.DirtyItem("potato"))
require.NoError(t, potato.Close(nil))
assert.Nil(t, c.DirtyItem("potato"))
}
func TestCacheExistsAndRemove(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
assert.False(t, c.Exists("potato"))
potato := c.Item("potato")
assert.False(t, c.Exists("potato"))
require.NoError(t, potato.Open(nil))
assert.True(t, c.Exists("potato"))
require.NoError(t, potato.Close(nil))
assert.True(t, c.Exists("potato"))
c.Remove("potato")
assert.False(t, c.Exists("potato"))
}
func TestCacheRename(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
// setup
assert.False(t, c.Exists("potato"))
potato := c.Item("potato")
require.NoError(t, potato.Open(nil))
require.NoError(t, potato.Close(nil))
assert.True(t, c.Exists("potato"))
osPath := c.toOSPath("potato")
osPathMeta := c.toOSPathMeta("potato")
assertPathExist(t, osPath)
assertPathExist(t, osPathMeta)
// rename potato -> newPotato
require.NoError(t, c.Rename("potato", "newPotato", nil))
assertPathNotExist(t, osPath)
assertPathNotExist(t, osPathMeta)
assert.False(t, c.Exists("potato"))
osPath = c.toOSPath("newPotato")
osPathMeta = c.toOSPathMeta("newPotato")
assertPathExist(t, osPath)
assertPathExist(t, osPathMeta)
assert.True(t, c.Exists("newPotato"))
// rename newPotato -> sub/newPotato
require.NoError(t, c.Rename("newPotato", "sub/newPotato", nil))
assertPathNotExist(t, osPath)
assertPathNotExist(t, osPathMeta)
assert.False(t, c.Exists("potato"))
osPath = c.toOSPath("sub/newPotato")
osPathMeta = c.toOSPathMeta("sub/newPotato")
assertPathExist(t, osPath)
assertPathExist(t, osPathMeta)
assert.True(t, c.Exists("sub/newPotato"))
// remove
c.Remove("sub/newPotato")
assertPathNotExist(t, osPath)
assertPathNotExist(t, osPathMeta)
assert.False(t, c.Exists("sub/newPotato"))
// non existent file - is ignored
assert.NoError(t, c.Rename("nonexist", "nonexist2", nil))
}
func TestCacheCleaner(t *testing.T) {
opt := vfscommon.DefaultOpt
opt.CachePollInterval = 10 * time.Millisecond
opt.CacheMaxAge = 20 * time.Millisecond
_, c, cleanup := newTestCacheOpt(t, opt)
defer cleanup()
time.Sleep(2 * opt.CachePollInterval)
potato := c.Item("potato")
potato2, found := c.get("potato")
assert.Equal(t, fmt.Sprintf("%p", potato), fmt.Sprintf("%p", potato2))
assert.True(t, found)
for i := 0; i < 100; i++ {
time.Sleep(10 * opt.CachePollInterval)
potato2, found = c.get("potato")
if !found {
break
}
}
assert.NotEqual(t, fmt.Sprintf("%p", potato), fmt.Sprintf("%p", potato2))
assert.False(t, found)
}
func TestCacheSetModTime(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
t1 := time.Date(2010, 1, 2, 3, 4, 5, 9, time.UTC)
potato := c.Item("potato")
require.NoError(t, potato.Open(nil))
require.NoError(t, potato.Truncate(5))
require.NoError(t, potato.Close(nil))
c.SetModTime("potato", t1)
osPath := potato.c.toOSPath("potato")
fi, err := os.Stat(osPath)
require.NoError(t, err)
fstest.AssertTimeEqualWithPrecision(t, "potato", t1, fi.ModTime(), time.Second)
}
func TestCacheTotaInUse(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
assert.Equal(t, int(0), c.TotalInUse())
potato := c.Item("potato")
assert.Equal(t, int(0), c.TotalInUse())
require.NoError(t, potato.Open(nil))
assert.Equal(t, int(1), c.TotalInUse())
require.NoError(t, potato.Truncate(5))
assert.Equal(t, int(1), c.TotalInUse())
potato2 := c.Item("potato2")
assert.Equal(t, int(1), c.TotalInUse())
require.NoError(t, potato2.Open(nil))
assert.Equal(t, int(2), c.TotalInUse())
require.NoError(t, potato2.Close(nil))
assert.Equal(t, int(1), c.TotalInUse())
require.NoError(t, potato.Close(nil))
assert.Equal(t, int(0), c.TotalInUse())
}
func TestCacheDump(t *testing.T) {
_, c, cleanup := newTestCache(t)
defer cleanup()
out := (*Cache)(nil).Dump()
assert.Equal(t, "Cache: <nil>\n", out)
out = c.Dump()
assert.Equal(t, "Cache{\n}\n", out)
c.Item("potato")
out = c.Dump()
want := "Cache{\n\t\"potato\": "
assert.Equal(t, want, out[:len(want)])
c.Remove("potato")
out = c.Dump()
assert.Equal(t, "Cache{\n}\n", out)
}