freeze when using from a C program

[Ludovic Drolez]

Hi !

Curlftpfs 0.9 seems to work when using it from a shell but from a C program, it hangs.
My program just tries to read 2 files, and on the 2nd open, ftpfs hang and loops getting the same file over and over:

with strace it's stuck to : open("/exclude", O_RDONLY

and ethereal loops on:
18   0.058585 192.168.0.244 -> 172.20.0.123 FTP Request: PASV
19   0.058709 172.20.0.123 -> 192.168.0.244 FTP Response: 227 Entering Passive
Mode (172,20,0,123,227,135)
20   0.059708 192.168.0.244 -> 172.20.0.123 TCP 2892 > 21 [ACK] Seq=1707352969
Ack=2704235897 Win=2920 Len=0
21   0.060334 192.168.0.244 -> 172.20.0.123 TCP 2370 > 58247 [SYN] Seq=19898400
05 Ack=0 Win=5840 Len=0
22   0.060358 172.20.0.123 -> 192.168.0.244 TCP 58247 > 2370 [SYN, ACK] Seq=300
6113560 Ack=1989840006 Win=5792 Len=0
23   0.061081 192.168.0.244 -> 172.20.0.123 TCP 2370 > 58247 [ACK] Seq=19898400
06 Ack=3006113561 Win=2920 Len=0
24   0.061459 192.168.0.244 -> 172.20.0.123 FTP Request: SIZE exclude
25   0.061538 172.20.0.123 -> 192.168.0.244 FTP Response: 213 0
26   0.062206 192.168.0.244 -> 172.20.0.123 FTP Request: RETR exclude
27   0.062345 172.20.0.123 -> 192.168.0.244 FTP Response: 150 Opening BINARY mo
de data connection for exclude (0 bytes).
28   0.062373 172.20.0.123 -> 192.168.0.244 FTP Response: 226 File send OK.
29   0.062394 172.20.0.123 -> 192.168.0.244 TCP 58247 > 2370 [FIN, ACK] Seq=300
6113561 Ack=1989840006 Win=5792 Len=0
30   0.064082 192.168.0.244 -> 172.20.0.123 TCP 2370 > 58247 [ACK] Seq=19898400
06 Ack=3006113562 Win=2920 Len=0
31   0.064209 192.168.0.244 -> 172.20.0.123 TCP 2370 > 58247 [FIN, ACK] Seq=198
9840006 Ack=3006113562 Win=2920 Len=0

I use libcurl 7.16.0, libfuse 2.5.3, and a 2.6.18.2 kernel.

Any ideas ?

  Ludo.

[Ludovic Drolez]

Update: the bug appears when a file is empty, and is opened 2 times.

example:

# cat exclude               (0 bytes)
# cat hdmap                 (17 bytes)
...
contents
...
# cat exclude
   FREEZE ! And loops as described above !

Any quick fix ?

  Ludovic.

[Robson Braga Araujo]

I can only reproduce this using libcurl 7.16.0. A quick fix for you would be to use an older version of libcurl. I'll look into this to see if it's a new libcurl bug or some bug in curlftpfs that got worse with the new libcurl version.

[Ludovic Drolez]

A quick fix could be avoiding to send a RETR when the size is 0 ?

[Ludovic Drolez]

Nice, with curl 7.15.5 it works.
FWI, I've managed to use Curlftpfs instead of NFS to make a disk image, using the Linbox Rescue Server ( http://lrs.linbox.org ), it includes ghost-like features to make disk images with a PXE boot.

It splits the backup in files of up to 90MB so I guess that the backuped system needs at least 128MB of RAM ?

Cheers,

   Ludo.