[LU-1550] open-by-fid getdents may return inconsistend data

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Affects Version/s: Lustre 2.3.0, Lustre 2.1.2
• Labels: fid readdir
• Environment: # 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
• Severity: 3
• Assignee: WC Triage
• Reporter: John Hammond

Description

getdents() on lustre client mount returns inconsistent/bad data. According to stat(), the /mnt/lustre inode has ino 0x61ab:

[root@r62-lustre lustre]# sys_stat -x /mnt/lustre
dev              2c54f966
ino                  61ab
mode                 41ed
nlink                   3
uid                     0
gid                     0
rdev                    0
size                 1000
blksize              1000
blocks                  8
atime            4fe3593b
mtime            4fe363e7
ctime            4fe363e7

While according to getdents() it does not. Instead we get the ino based on its
FID. (Note that the output of `ls -ai /mnt/lustre' is not based
entirely on the output of getdents().)

[root@r62-lustre lustre]# sys_getdents -x /mnt/lustre
d             61ac `.lustre'
d  20000000100000d `..'
d  200000001000006 `.'

Also for a mount point shouldn't the entries for '.' and '..' have the same d_ino?

Calling path2fid on /mnt/lustre returns [0x61ab:0xc04ebc0f:0x0], and
accessing /mnt/lustre thereby seems OK. However the FID derived from
the d_ino for '.' in /mnt/lustre offers a cache-incoherent view on
that directory:

# cd /mnt/lustre
[root]# stat .
  File: `.'
  Size: 4096            Blocks: 8          IO Block: 4096   directory
Device: 2c54f966h/743766374d    Inode: 25003       Links: 3
Access: (0755/drwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2012-06-21 12:26:19.000000000 -0500
Modify: 2012-06-21 13:11:51.000000000 -0500
Change: 2012-06-21 13:11:51.000000000 -0500
[root]# stat .lustre/fid/[0x200000001:0x6:0x0]
  File: `.lustre/fid/[0x200000001:0x6:0x0]'
  Size: 4096            Blocks: 8          IO Block: 4096   directory
Device: 2c54f966h/743766374d    Inode: 144115188092633094  Links: 3
Access: (0755/drwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2012-06-21 13:39:08.000000000 -0500
Modify: 2012-06-21 13:39:19.000000000 -0500
Change: 2012-06-21 13:39:19.000000000 -0500

[root]# cd /mnt/lustre
[root]# ls -a
.  ..  .lustre
[root]# ls -a .lustre/fid/[0x200000001:0x6:0x0]
.  ..  .lustre

[root]# touch FOO
[root]# ls -a
.  ..  FOO  .lustre
[root]# ls -a .lustre/fid/[0x200000001:0x6:0x0]
.  ..  .lustre

[root]# touch .lustre/fid/[0x200000001:0x6:0x0]/BAR
[root]# ls -a
.  ..  FOO  .lustre
[root]# ls -a .lustre/fid/[0x200000001:0x6:0x0]
.  ..  BAR  FOO  .lustre

[root]# touch BAZ
[root]# ls -a
.  ..  BAR  BAZ  FOO  .lustre
[root]# ls -a .lustre/fid/[0x200000001:0x6:0x0]
.  ..  BAR  FOO  .lustre

Issue Links

• duplicates: LU-838 "lfs path2fid /mnt/lustre" (ROOT) returns inode number
• is related to: LU-1518 Missing/bad operations in mdd_{obf,dot_lustre}_obj_op causing LBUGs