From: Konstantin Khorenko <[email protected]>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 3aa6e0aa8ab3e64bbfba092c64d42fd1d006b124 upstream.

If nfsd fails to find an exported via NFS file in the readahead cache, it
should increment corresponding nfsdstats counter (ra_depth[10]), but due to a
bug it may instead write to ra_depth[11], corrupting the following field.

In a kernel with NFSDv4 compiled in the corruption takes the form of an
increment of a counter of the number of NFSv4 operation 0's received; since
there is no operation 0, this is harmless.

In a kernel with NFSDv4 disabled it corrupts whatever happens to be in the
memory beyond nfsdstats.

Signed-off-by: Konstantin Khorenko <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>
Signed-off-by: Paul Gortmaker <[email protected]>
---
 fs/nfsd/vfs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 4eb9baa..054b50b 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -819,7 +819,7 @@ nfsd_get_raparms(dev_t dev, ino_t ino)
                if (ra->p_count == 0)
                        frap = rap;
        }
-       depth = nfsdstats.ra_size*11/10;
+       depth = nfsdstats.ra_size;
        if (!frap) {    
                spin_unlock(&rab->pb_lock);
                return NULL;
-- 
1.7.4.4

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