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authorTrond Myklebust <trond.myklebust@hammerspace.com>2021-03-29 23:46:05 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-05-19 11:08:25 +0300
commitbdbee0d845202f41179c9bdfd9e8415fd68aa13f (patch)
tree6dc4c08fb9ea3754c6ad517e1f4af6cd2aff8f99
parent7e16709fc540135fdef5d07fb5965c36ee057ab3 (diff)
downloadlinux-bdbee0d845202f41179c9bdfd9e8415fd68aa13f.tar.xz
NFS: Deal correctly with attribute generation counter overflow
[ Upstream commit 9fdbfad1777cb4638f489eeb62d85432010c0031 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--fs/nfs/inode.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 53604cc090ca..8c0f916380c4 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1618,10 +1618,10 @@ 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)
@@ -2049,7 +2049,7 @@ 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;
}