From: Fabio Olive Leite <fleite@redhat.com>
Subject: Re: [PATCH] Attribute timeout handling and wrapping u32
	jiffies
Date: Thu, 26 Jul 2007 22:59:00 -0300
Message-ID: <20070727015900.GA3000@sleipnir.redhat.com>
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	<1185372013.6585.73.camel@localhost>
	<20070725142824.GA24321@sleipnir.redhat.com>
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To: linux-nfs <nfs@lists.sourceforge.net>
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On Wed, Jul 25, 2007 at 10:32:59AM -0400, Trond Myklebust wrote:
> =

> No. IMO [b;c] should be the range for the generic function, and it
> should be up to the NFS code to do the 'stored jiffies + constant
> timeout' calculation. You will note that time_in_range() does in any
> case return true if you are inside the valid time range, so you will
> usually want to do
> =

> if (!time_in_range())...
> =

> in order to do the timeout_or_wrap() test.

Tried it out and it behaves correctly. Thanks for your suggestions.
The patch below is the final version, and fixes the attribute timeout
issue with wrapping jiffies.

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index ea97408..54d3926 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1852,7 +1852,7 @@ int nfs_access_get_cached(struct inode *inode, struct=
 rpc_cred *cred, struct nfs
 	cache =3D nfs_access_search_rbtree(inode, cred);
 	if (cache =3D=3D NULL)
 		goto out;
-	if (time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)))
+	if (!time_in_range(jiffies, cache->jiffies, cache->jiffies + NFS_ATTRTIME=
O(inode)))
 		goto out_stale;
 	res->jiffies =3D cache->jiffies;
 	res->cred =3D cache->cred;
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index bca6cdc..89c3e91 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -662,7 +662,7 @@ int nfs_attribute_timeout(struct inode *inode)
 =

 	if (nfs_have_delegation(inode, FMODE_READ))
 		return 0;
-	return time_after(jiffies, nfsi->read_cache_jiffies+nfsi->attrtimeo);
+	return !time_in_range(jiffies, nfsi->read_cache_jiffies, nfsi->read_cache=
_jiffies + nfsi->attrtimeo);
 }
 =

 /**
@@ -1061,7 +1061,7 @@ static int nfs_update_inode(struct inode *inode, stru=
ct nfs_fattr *fattr)
 		nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
 		nfsi->attrtimeo =3D NFS_MINATTRTIMEO(inode);
 		nfsi->attrtimeo_timestamp =3D now;
-	} else if (time_after(now, nfsi->attrtimeo_timestamp+nfsi->attrtimeo)) {
+	} else if (!time_in_range(now, nfsi->attrtimeo_timestamp, nfsi->attrtimeo=
_timestamp + nfsi->attrtimeo)) {
 		if ((nfsi->attrtimeo <<=3D 1) > NFS_MAXATTRTIMEO(inode))
 			nfsi->attrtimeo =3D NFS_MAXATTRTIMEO(inode);
 		nfsi->attrtimeo_timestamp =3D now;
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index c080f61..f1c87ad 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -115,6 +115,10 @@ static inline u64 get_jiffies_64(void)
 	 ((long)(a) - (long)(b) >=3D 0))
 #define time_before_eq(a,b)	time_after_eq(b,a)
 =

+#define time_in_range(a,b,c) \
+	(time_after_eq(a,b) && \
+	 time_before_eq(a,c))
+
 /* Same as above, but does so with platform independent 64bit types.
  * These must be used when utilizing jiffies_64 (i.e. return value of
  * get_jiffies_64() */

Cheers!
F=E1bio
-- =

ex sed lex awk yacc, e pluribus unix, amem

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