On Apr 4, 2007, at 4:37 PM, Phil Carns wrote:
Hi Phil,
Good idea to look at the other file systems. My (admittedly
limited) understanding of disconnected dentries is based on the
Documentation/ filesystems/Exporting doc, which may be a bit
outdated. It suggests that lookup should return whatever
d_splice_alias returns (assuming the inode exists), which may
return NULL when the dentry is disconnected?
Also, it seems clear that ENOENT cases require returning NULL.
-sam
Ok, I think we are converging on something here :) Your latest
namei3 patch seems to do what you describe, except for the part
about returning whatever d_splice_alias() returns. I experimented
by modifying line 213 of namei.c after applying your patch, so that
rather than returning "NULL", it returns "res".
On 2.6 kernels, this still passes all LTP tests and handles
deleting renamed directories without complaint. On 2.4 kernels it
causes a kernel crash when deleting renamed directories. I think
both of these results confirm what we see from other file systems:
on 2.6 we should pass along the return code of d_splice_alias(),
while on 2.4 we should always return NULL.
I doubt that there is a feature test for this- kinda hard to tell
when there is a semantic change to the vfs lookup function.
Do you think that we should go with your patch plus a "#ifdef
PVFS2_LINUX_KERNEL_2_4" wrapper to control whether it returns NULL
or res on that one line?
Yeah. Sounds good to me. I can commit unless there are other
objections.
-sam
-Phil
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