Upstream commit 3f015d89a47cd8855cd92f71fff770095bd885a1 backported for stable v4.9:
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The mechanism in use to allow the client to see the results of COPY/CLONE is to drop those pages from the pagecache. This forces the client to read those pages once more from the server. However, truncate_pagecache_range() zeros out partial pages instead of dropping them. Let us instead use invalidate_inode_pages2_range() with full-page offsets to ensure the client properly sees the results of COPY/CLONE operations.
Cc: stable@vger.kernel.org # v4.7+ Fixes: 2e72448b07dc ("NFS: Add COPY nfs operation") Signed-off-by: Benjamin Coddington bcodding@redhat.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com --- fs/nfs/nfs42proc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c index 7efb9e0e9f25..3038cefff15c 100644 --- a/fs/nfs/nfs42proc.c +++ b/fs/nfs/nfs42proc.c @@ -181,8 +181,9 @@ static ssize_t _nfs42_proc_copy(struct file *src, return status; }
- truncate_pagecache_range(dst_inode, pos_dst, - pos_dst + res->write_res.count); + WARN_ON_ONCE(invalidate_inode_pages2_range(dst_inode->i_mapping, + pos_dst >> PAGE_SHIFT, + (pos_dst + res->write_res.count - 1) >> PAGE_SHIFT));
return res->write_res.count; }