OpenE2K
/
linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

NFS: Ensure that 'noac' and/or 'actimeo=0' turn off attribute caching 

Both the 'noac' and 'actimeo=0' mount options should ensure that attributes
are not cached, however a bug in nfs_attribute_timeout() means that
currently, the attributes may in fact get cached for up to one jiffy. This
has been seen to cause corruption in some applications.

The reason for the bug is that the time_in_range() test returns 'true' as
long as the current time lies between nfsi->read_cache_jiffies and
nfsi->read_cache_jiffies + nfsi->attrtimeo. In other words, if jiffies
equals nfsi->read_cache_jiffies, then we still cache the attribute data.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2008-05-05 11:45:41 -04:00
parent f26a398891
commit b0b539739f
1 changed files with 7 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
fs/nfs/inode.c
View File

@ -707,6 +707,13 @@ int nfs_attribute_timeout(struct inode *inode)
if (nfs_have_delegation(inode, FMODE_READ))
return 0;
/*
* Special case: if the attribute timeout is set to 0, then always
* treat the cache as having expired (unless holding
* a delegation).
*/
if (nfsi->attrtimeo == 0)
return 1;
return !time_in_range(jiffies, nfsi->read_cache_jiffies, nfsi->read_cache_jiffies + nfsi->attrtimeo);
}