[ 79/98] nfsd: fix bad offset use

Greg Kroah-Hartman
2013-03-26T22:49:47Z

From: Kent Overstreet <koverstreet@google.com>

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@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Zach Brown <zab@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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;