[PATCH 3.2 055/102] NFSv4: Fix another bug in the close/open_downgrade code

From: Ben Hutchings
Date: Sat Nov 01 2014 - 18:48:59 EST


3.2.64-rc1 review patch. If anyone has any objections, please let me know.

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

From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>

commit cd9288ffaea4359d5cfe2b8d264911506aed26a4 upstream.

James Drew reports another bug whereby the NFS client is now sending
an OPEN_DOWNGRADE in a situation where it should really have sent a
CLOSE: the client is opening the file for O_RDWR, but then trying to
do a downgrade to O_RDONLY, which is not allowed by the NFSv4 spec.

Reported-by: James Drews <drews@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/541AD7E5.8020409@xxxxxxxxxxxxx
Fixes: aee7af356e15 (NFSv4: Fix problems with close in the presence...)
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2015,23 +2015,23 @@ static void nfs4_close_prepare(struct rp
is_rdwr = test_bit(NFS_O_RDWR_STATE, &state->flags);
is_rdonly = test_bit(NFS_O_RDONLY_STATE, &state->flags);
is_wronly = test_bit(NFS_O_WRONLY_STATE, &state->flags);
- /* Calculate the current open share mode */
- calldata->arg.fmode = 0;
- if (is_rdonly || is_rdwr)
- calldata->arg.fmode |= FMODE_READ;
- if (is_wronly || is_rdwr)
- calldata->arg.fmode |= FMODE_WRITE;
/* Calculate the change in open mode */
+ calldata->arg.fmode = 0;
if (state->n_rdwr == 0) {
- if (state->n_rdonly == 0) {
- call_close |= is_rdonly || is_rdwr;
- calldata->arg.fmode &= ~FMODE_READ;
- }
- if (state->n_wronly == 0) {
- call_close |= is_wronly || is_rdwr;
- calldata->arg.fmode &= ~FMODE_WRITE;
- }
- }
+ if (state->n_rdonly == 0)
+ call_close |= is_rdonly;
+ else if (is_rdonly)
+ calldata->arg.fmode |= FMODE_READ;
+ if (state->n_wronly == 0)
+ call_close |= is_wronly;
+ else if (is_wronly)
+ calldata->arg.fmode |= FMODE_WRITE;
+ } else if (is_rdwr)
+ calldata->arg.fmode |= FMODE_READ|FMODE_WRITE;
+
+ if (calldata->arg.fmode == 0)
+ call_close |= is_rdwr;
+
spin_unlock(&state->owner->so_lock);

if (!call_close) {

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