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NFSv4: When returning a delegation, don't reclaim an incompatible open mode. 

It is possible to have an active open with one mode, and a delegation
for the same file with a different mode.
In particular, a WR_ONLY open and an RD_ONLY delegation.
This happens if a WR_ONLY open is followed by a RD_ONLY open which
provides a delegation, but is then close.

When returning the delegation, we currently try to claim opens for
every open type (n_rdwr, n_rdonly, n_wronly).  As there is no harm
in claiming an open for a mode that we already have, this is often
simplest.

However if the delegation only provides a subset of the modes that we
currently have open, this will produce an error from the server.

So when claiming open modes prior to returning a delegation, skip the
open request if the mode is not covered by the delegation - the open_stateid
must already cover that mode, so there is nothing to do.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
NeilBrown 2015-06-29 14:28:54 +10:00 committed by Trond Myklebust
parent 6c5a0d8915
commit 39f897fdbd
1 changed files with 7 additions and 0 deletions
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7
fs/nfs/nfs4proc.c
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@ -1547,6 +1547,13 @@ static int nfs4_open_recover_helper(struct nfs4_opendata *opendata, fmode_t fmod
struct nfs4_state *newstate;
int ret;
if ((opendata->o_arg.claim == NFS4_OPEN_CLAIM_DELEGATE_CUR ||
opendata->o_arg.claim == NFS4_OPEN_CLAIM_DELEG_CUR_FH) &&
(opendata->o_arg.u.delegation_type & fmode) != fmode)
/* This mode can't have been delegated, so we must have
* a valid open_stateid to cover it - not need to reclaim.
*/
return 0;
opendata->o_arg.open_flags = 0;
opendata->o_arg.fmode = fmode;
opendata->o_arg.share_access = nfs4_map_atomic_open_share(