Fri Sep 9 16:54:00 GMT 2005
Module name: cluster
Changes by: firstname.lastname@example.org 2005-09-09 16:54:25
Really gross hack!!!
This is a workaround for one of the bugs the got lumped into 166701. It
breaks POSIX behavior in a corner case to avoid crashing... It's icky.
when NFS opens a file with O_CREAT, the kernel nfs daemon checks to see
if the file exists. If it does, nfsd does the *right thing* (either opens the
file, or if the file was opened with O_EXCL, returns an error). If the file
doesn't exist, it passes the request down to the underlying file system.
Unfortunately, since nfs *knows* that the file doesn't exist, it doesn't
bother to pass a nameidata structure, which would include the intent
information. However since gfs is a cluster file system, the file could have
been created on another node after nfs checks for it. If this is the case,
gfs needs the intent information to do the *right thing*. It panics when
it finds a NULL pointer, instead of the nameidata. Now, instead of panicing,
if gfs finds a NULL nameidata pointer. It assumes that the file was not
created with O_EXCL.
This assumption could be wrong, with the result that an application could
thing that it has created a new file, when in fact, it has opened an existing
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