Commit e547f262 authored Jun 25, 2016 by Trond Myklebust Committed by Anna Schumaker Jun 28, 2016

NFS: Fix another OPEN_DOWNGRADE bug



Olga Kornievskaia reports that the following test fails to trigger
an OPEN_DOWNGRADE on the wire, and only triggers the final CLOSE.

	fd0 = open(foo, RDRW)   -- should be open on the wire for "both"
	fd1 = open(foo, RDONLY)  -- should be open on the wire for "read"
	close(fd0) -- should trigger an open_downgrade
	read(fd1)
	close(fd1)

The issue is that we're missing a check for whether or not the current
state transitioned from an O_RDWR state as opposed to having transitioned
from a combination of O_RDONLY and O_WRONLY.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: cd9288ff ("NFSv4: Fix another bug in the close/open_downgrade code")
Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

parent d20cb71d

fs/nfs/nfs4proc.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -2882,12 +2882,11 @@ static void nfs4_close_prepare(struct rpc_task task, void data)
		call_close \|= is_wronly;
		else if (is_wronly)
		calldata->arg.fmode \|= FMODE_WRITE;
		if (calldata->arg.fmode != (FMODE_READ\|FMODE_WRITE))
		call_close \|= is_rdwr;
		} else if (is_rdwr)
		calldata->arg.fmode \|= FMODE_READ\|FMODE_WRITE;

		if (calldata->arg.fmode == 0)
		call_close \|= is_rdwr;

		if (!nfs4_valid_open_stateid(state))
		call_close = 0;
		spin_unlock(&state->owner->so_lock);

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