question: dcache race cdns

Peter J. Braam (braam@cs.cmu.edu)
Sat, 20 Dec 1997 17:49:10 -0500 (EST)


Hi Bill,

Things are working now with the dcache in Coda. Thanks for your help.

I wondered if it is safe for a file system to iterate through the
d_subdirs and set a flag in the inode? Is any locking needed?

A second question is the following. I saw that NFS carefully unhashes the
entry before doing an rmdir. This seems to avoid a race condition between
different processes gaining access to the dentry. Should all filesystems
do this? Are similar things the case for rename of directories? (It would
seem so.) Why does avoiding these race conditions not apply to files?

Thanks for any insight!!

_ Peter _