[ 79/98] nfsd: fix bad offset use

[Greg Kroah-Hartman]

3.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kent Overstreet <koverstreet@xxxxxxxxxx>

commit e49dbbf3e770aa590a8a464ac4978a09027060b9 upstream.

vfs_writev() updates the offset argument - but the code then passes the
offset to vfs_fsync_range(). Since offset now points to the offset after
what was just written, this is probably not what was intended

Introduced by face15025ffdf664de95e86ae831544154d26c9c "nfsd: use
vfs_fsync_range(), not O_SYNC, for stable writes".

Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Reviewed-by: Zach Brown <zab@xxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/nfsd/vfs.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1013,6 +1013,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s
 	int			host_err;
 	int			stable = *stablep;
 	int			use_wgather;
+	loff_t			pos = offset;
 
 	dentry = file->f_path.dentry;
 	inode = dentry->d_inode;
@@ -1025,7 +1026,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s
 
 	/* Write the data. */
 	oldfs = get_fs(); set_fs(KERNEL_DS);
-	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
+	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos);
 	set_fs(oldfs);
 	if (host_err < 0)
 		goto out_nfserr;


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