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From: trondmy@kernel.org
To: linux-nfs@vger.kernel.org
Subject: [PATCH 01/17] NFS: Deal correctly with attribute generation counter overflow
Date: Mon, 29 Mar 2021 20:18:19 -0400	[thread overview]
Message-ID: <20210330001835.41914-2-trondmy@kernel.org> (raw)
In-Reply-To: <20210330001835.41914-1-trondmy@kernel.org>

From: Trond Myklebust <trond.myklebust@hammerspace.com>

We need to use unsigned long subtraction and then convert to signed in
order to deal correcly with C overflow rules.

Fixes: f5062003465c ("NFS: Set an attribute barrier on all updates")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/inode.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index ff737be559dc..8de5b3b9da91 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1662,10 +1662,10 @@ EXPORT_SYMBOL_GPL(_nfs_display_fhandle);
  */
 static int nfs_inode_attrs_need_update(const struct inode *inode, const struct nfs_fattr *fattr)
 {
-	const struct nfs_inode *nfsi = NFS_I(inode);
+	unsigned long attr_gencount = NFS_I(inode)->attr_gencount;
 
-	return ((long)fattr->gencount - (long)nfsi->attr_gencount) > 0 ||
-		((long)nfsi->attr_gencount - (long)nfs_read_attr_generation_counter() > 0);
+	return (long)(fattr->gencount - attr_gencount) > 0 ||
+	       (long)(attr_gencount - nfs_read_attr_generation_counter()) > 0;
 }
 
 static int nfs_refresh_inode_locked(struct inode *inode, struct nfs_fattr *fattr)
@@ -2094,7 +2094,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 			nfsi->attrtimeo_timestamp = now;
 		}
 		/* Set the barrier to be more recent than this fattr */
-		if ((long)fattr->gencount - (long)nfsi->attr_gencount > 0)
+		if ((long)(fattr->gencount - nfsi->attr_gencount) > 0)
 			nfsi->attr_gencount = fattr->gencount;
 	}
 
-- 
2.30.2


  reply	other threads:[~2021-03-30  0:19 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-30  0:18 [PATCH 00/17] Attribute revalidation updates trondmy
2021-03-30  0:18 ` trondmy [this message]
2021-03-30  0:18   ` [PATCH 02/17] NFS: Fix up inode cache tracing trondmy
2021-03-30  0:18     ` [PATCH 03/17] NFS: Mask out unsupported attributes in nfs_getattr() trondmy
2021-03-30  0:18       ` [PATCH 04/17] NFS: NFS_INO_REVAL_PAGECACHE should mark the change attribute invalid trondmy
2021-03-30  0:18         ` [PATCH 05/17] NFS: Fix up revalidation of space used trondmy
2021-03-30  0:18           ` [PATCH 06/17] NFS: Don't revalidate attributes that are not being asked for trondmy
2021-03-30  0:18             ` [PATCH 07/17] NFS: Fix up statx() results trondmy
2021-03-30  0:18               ` [PATCH 08/17] NFS: Add a cache validity flag argument to nfs_revalidate_inode() trondmy
2021-03-30  0:18                 ` [PATCH 09/17] NFS: Replace use of NFS_INO_REVAL_PAGECACHE when checking cache validity trondmy
2021-03-30  0:18                   ` [PATCH 10/17] NFS: Don't set NFS_INO_REVAL_PAGECACHE in the inode " trondmy
2021-03-30  0:18                     ` [PATCH 11/17] NFS: Separate tracking of file nlinks cache validity from the mode/uid/gid trondmy
2021-03-30  0:18                       ` [PATCH 12/17] NFS: Fix up handling of outstanding layoutcommit in nfs_update_inode() trondmy
2021-03-30  0:18                         ` [PATCH 13/17] NFS: Remove a line of code that has no effect " trondmy
2021-03-30  0:18                           ` [PATCH 14/17] NFS: Simplify cache consistency in nfs_check_inode_attributes() trondmy
2021-03-30  0:18                             ` [PATCH 15/17] NFSv4: Fix value of decode_fsinfo_maxsz trondmy
2021-03-30  0:18                               ` [PATCH 16/17] NFSv4: Add support for the NFSv4.2 "change_attr_type" attribute trondmy
2021-03-30  0:18                                 ` [PATCH 17/17] NFS: Use information about the change attribute to optimise updates trondmy

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