la la land

[Michael Bilow]

Well, this is Boston Linux and UNIX, so it qualifies.

This is pretty mystifying.  My best guess is that the directory is hosed.  
Unix directories are just files, like any other: they have owners and
permissions, and processes which have sufficient permissions can lock
them.  If the directory is being actually modified, then it could be
locked against read for an instant.  If something is rapidly creating and
deleting files, the probability that you will try to read the directory
during the instant it is locked will increase.

Unix filesystems do all sorts of strange things by design.  For example,
you can delete an open file, and then when it is closed and its reference
count drops to zero, it will be purged.  This is strange.

-- Mike


On 2001-01-18 at 10:46 -0500, Ron Peterson wrote:

> Not strictly a linux question, but I'm hoping someone on this list might
> have some insight.  How can a file disappear and then reappear again?  I
> know that sounds ridiculous, but look at the following:
> 
> # ls -li passwd ; date
> 63444 -rw-r--r--   1 root     system    967593 Jan 17 15:20 passwd
> Wed Jan 17 15:38:26 EST 2001
> # ls -li passwd ; date
> ls: passwd not found
> Wed Jan 17 15:38:27 EST 2001
> # ls -li passwd ; date
> 63444 -rw-r--r--   1 root     system    967593 Jan 17 15:20 passwd
> Wed Jan 17 15:38:28 EST 2001
> # ls -li passwd ; date
> ls: passwd not found
> Wed Jan 17 15:38:28 EST 2001
> # ls -li passwd ; date
> ls: passwd not found
> Wed Jan 17 15:38:29 EST 2001
> # ls -li passwd ; date
> 63444 -rw-r--r--   1 root     system    967593 Jan 17 15:20
> passwd         
> 
> This makes the problem go away.  For awhile anyway.
>   
> # mv passwd p
> # cp p passwd
> #
> #
> # ls -li passwd ; date
> 88967 -rw-r--r--   1 root     system    967593 Jan 17 15:38 passwd
> Wed Jan 17 15:38:55 EST 2001
> # ls -li passwd ; date
> 88967 -rw-r--r--   1 root     system    967593 Jan 17 15:38 passwd
> Wed Jan 17 15:38:56 EST 2001
> etc.
> 
> This is on Tru64 on a DS20.  OS bug?  Filesystem corruption?  Any ideas
> for further diagnositic work?
> 
> -Ron-


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