[Lustre-devel] a bug in "lfs find" command (patch attached)

[Yuriy Umanets]

hi Lustre people,

One of our clients has found the bug in lfs find, which we have fixed. Patch
is attached. Issue is that find_value_cmp() and how it gets params are
buggy. Inversion made by inverting sign is completely wrong idea. Please see
the patch for details.

Examples:

Let's create some files and try to find them:

[root at victim tests]# touch /mnt/lustre/a
[root at victim tests]# touch /mnt/lustre/b
[root at victim tests]# echo 1 > /mnt/lustre/c
[root at victim tests]# ls -la /mnt/lustre/
total 12
drwxr-xr-x  2 root root 4096 May 29 12:31 .
drwxr-xr-x 11 root root 4096 May  4 22:50 ..
-rw-r--r--  1 root root    0 May 29 12:31 a
-rw-r--r--  1 root root    0 May 29 12:31 b
-rw-r--r--  1 root root    2 May 29 12:31 c

As you can see, there are 2 zero length files and one 2 bytes long file.

Example of how it worked before fix:

[root at victim tests]# ../utils/lfs find /mnt/lustre -s 0

That is nothing found.

[root at victim tests]# ../utils/lfs find /mnt/lustre -s 2

Again nothing is found.

[root at victim tests]# ../utils/lfs find /mnt/lustre ! -s 0

Search for non zero length files also gives nothing.

[root at victim tests]# ../utils/lfs find /mnt/lustre ! -s 1
/mnt/lustre/a
/mnt/lustre/b

This finds two zero files but does not find one 2 bytes long file.

After the fix:

[root at victim tests]# ../utils/lfs find /mnt/lustre -s 0
/mnt/lustre/a
/mnt/lustre/b

[root at victim tests]# ../utils/lfs find /mnt/lustre -s 2
/mnt/lustre/c

[root at victim tests]# ../utils/lfs find /mnt/lustre ! -s 0
/mnt/lustre
/mnt/lustre/c

[root at victim tests]# ../utils/lfs find /mnt/lustre ! -s 1
/mnt/lustre
/mnt/lustre/a
/mnt/lustre/b
/mnt/lustre/c

[root at victim tests]# ../utils/lfs find /mnt/lustre -s +1
/mnt/lustre
/mnt/lustre/c

This found all with size 1 and more.

[root at victim tests]# ../utils/lfs find /mnt/lustre -s -1
/mnt/lustre/a
/mnt/lustre/b

This found all smaller than 1 byte long.

[root at victim tests]# ../utils/lfs find /mnt/lustre -s -0
/mnt/lustre/a
/mnt/lustre/b

This found all that 0 or smaller :)

Should I create bug in bugzilla or posting it to lustre-devel@ is ok?

Thanks.
-- 
umka
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