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//go:build linux
// +build linux
/*
Small tool to try to debug unix.Getdents problems on CIFS mounts
( https://github.com/rfjakob/gocryptfs/issues/483 )
Example output:
$ while sleep 1 ; do ./getdents /mnt/synology/public/tmp/g1 ; done
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=3192, err=<nil>
unix.Getdents fd3: n=0, err=<nil>
total 24072 bytes
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=-1, err=no such file or directory
total 16704 bytes
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=4176, err=<nil>
unix.Getdents fd3: n=3192, err=<nil>
unix.Getdents fd3: n=0, err=<nil>
total 24072 bytes
Failure looks like this in strace:
[pid 189974] getdents64(6, 0xc000105808, 10000) = -1 ENOENT (No such file or directory)
*/
package main
import (
"flag"
"fmt"
"os"
"time"
"golang.org/x/sys/unix"
)
const (
myName = "getdents"
)
func main() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s PATH\n", myName)
fmt.Fprintf(os.Stderr, "Run getdents(2) on PATH in a 100ms loop until we hit an error\n")
os.Exit(1)
}
flag.Parse()
if flag.NArg() != 1 {
flag.Usage()
}
path := flag.Arg(0)
tmp := make([]byte, 10000)
for i := 1; ; i++ {
sum := 0
fd, err := unix.Open(path, unix.O_RDONLY, 0)
if err != nil {
fmt.Printf("%3d: unix.Open returned err=%v\n", i, err)
os.Exit(1)
}
fmt.Printf("%3d: unix.Getdents: ", i)
for {
n, err := unix.Getdents(fd, tmp)
fmt.Printf("n=%d; ", n)
if n <= 0 {
fmt.Printf("err=%v; total %d bytes\n", err, sum)
if err != nil {
os.Exit(1)
}
break
}
sum += n
}
unix.Close(fd)
time.Sleep(100 * time.Millisecond)
}
}
|
