[LU-1549] open-unlinked files are accessible through the PENDING directory

Duplicate — Tue, 29 Apr 2014 20:13:22 +0000

Open-unlinked files can be read (depending on inode/process permissions) through the PENDING directory.

root]# w# cat /proc/fs/lustre/version
lustre: 2.2.55
kernel: patchless_client
build:  2.2.55-gef32640-CHANGED-2.6.32-220.13.1.el6.l22.x86_64
hoami
root
[root]# cd /mnt/lustre
[root]# lsof /mnt/lustre
COMMAND   PID   USER   FD   TYPE      DEVICE SIZE/OFF  NODE NAME
lsof     4392   root  cwd    DIR 1273,181606   376832 25003 /mnt/lustre
lsof     4393   root  cwd    DIR 1273,181606   376832 25003 /mnt/lustre
bash    20096   root  cwd    DIR 1273,181606   376832 25003 /mnt/lustre
bash    21418 sanity  cwd    DIR 1273,181606   376832 25003 /mnt/lustre
[root]# echo SEACREST > PASSWORD
[root]# exec 3<PASSWORD
[root]# rm -f PASSWORD
[root]# lsof /mnt/lustre
COMMAND   PID   USER   FD   TYPE      DEVICE SIZE/OFF               NODE NAME
lsof     4575   root  cwd    DIR 1273,181606   376832              25003 /mnt/lustre
lsof     4576   root  cwd    DIR 1273,181606   376832              25003 /mnt/lustre
bash    20096   root  cwd    DIR 1273,181606   376832              25003 /mnt/lustre
bash    20096   root    3r   REG 1273,181606        9 144115206094586102 /mnt/lustre/PASSWORD (dele\
ted)
bash    21418 sanity  cwd    DIR 1273,181606   376832              25003 /mnt/lustre

sys_getdents is equivalent to `ls -ia' but prints d_type as well.

[sanity]$ whoami
sanity
[sanity]$ cd /mnt/lustre
[sanity]$ sys_getdents -x .
d  200000001000006 `.'
d  20000000100000d `..'
d             61ac `.lustre'
[sanity]$ sys_getdents -x .lustre/fid/[0x200000001:0xd:0x0] | grep ^d
d                c `CONFIGS'
d          b000000 `lost+found'
d          2000000 `.'
d             61ab `ROOT'
d          2000000 `..'
d             61a9 `OBJECTS'
d             61aa `PENDING'
d                e `NIDTBL_VERSIONS'
[sanity]$ cd .lustre/fid/[0x200000001:0xd:0x0]/PENDING
[sanity]$ sys_getdents -x . ## PENDING dirpages not cache coherent.
d  200000001000007 `.'
r  2000004320000a2 `0000000200000432:000000a2:00000000: 0'
d  20000000100000d `..'
[sanity]$ cat '0000000200000432:000000a2:00000000: 0'
cat: 0000000200000432:000000a2:00000000: 0: No such file or directory
[sanity]$ stat '0000000200000432:000000a2:00000000: 0'
stat: cannot stat `0000000200000432:000000a2:00000000: 0': No such file or directory
$ touch SANITY ## Force PENDING dirpages to be reread.
touch: cannot touch `SANITY': Permission denied
$ sys_getdents -x .
r  2000004320000f6 `0000000200000432:000000f6:00000000: 0'
d  200000001000007 `.'
d  20000000100000d `..'

We can't open these files unless we stat() (or accesss()) them first.

$ cat '0000000200000432:000000f6:00000000: 0'
cat: 0000000200000432:000000f6:00000000: 0: No such file or directory
$ stat '0000000200000432:000000f6:00000000: 0'
  File: `0000000200000432:000000f6:00000000: 0'
  Size: 9                                    Blocks: 8          IO Block: 2097152 regular file
Device: 2c54f966h/743766374d                 Inode: 144115206094586102  Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2012-06-20 16:24:14.000000000 -0500
Modify: 2012-06-20 16:24:14.000000000 -0500
Change: 2012-06-20 16:24:21.000000000 -0500
$ cat '0000000200000432:000000f6:00000000: 0'
SEACREST

In 2.1.2, I'm not sure how to access the ldiskfs root, but the FID of
the PENDING directory can be guessed from that of the ROOT (maybe it's
always the same anyway).

[sanity]$ lfs path2fid .
[0x61ab:0x46d01c7d:0x0]
$ sys_getdents -x .lustre/fid/[0x61aa:0x46d01c7c:0x0]
r  200000400000001 `0000000200000400:00000001:00000000: 0'
d             61aa `.'
d          2000000 `..'
[sanity]$ cat '.lustre/fid/[0x61aa:0x46d01c7c:0x0]/0000000200000400:00000001:00000000: 0'
SEACREST

Whamcloud Community JIRA

[LU-1549] open-unlinked files are accessible through the PENDING directory