5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: J. Bruce Fields bfields@redhat.com
[ Upstream commit 3dcd1d8aab00c5d3a0a3725253c86440b1a0f5a7 ]
The use of the bitmaps is confusing. Add a cross-reference to make it easier to find the existing comment. Add an updated reference with URL to make it quicker to look up. And a bit more editorializing about the value of this.
Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs4state.c | 14 ++++++++++---- fs/nfsd/state.h | 4 ++++ 2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 0b39ed1568d40..3b8c5f2283975 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -360,11 +360,13 @@ static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = { * st_{access,deny}_bmap field of the stateid, in order to track not * only what share bits are currently in force, but also what * combinations of share bits previous opens have used. This allows us - * to enforce the recommendation of rfc 3530 14.2.19 that the server - * return an error if the client attempt to downgrade to a combination - * of share bits not explicable by closing some of its previous opens. + * to enforce the recommendation in + * https://datatracker.ietf.org/doc/html/rfc7530#section-16.19.4 that + * the server return an error if the client attempt to downgrade to a + * combination of share bits not explicable by closing some of its + * previous opens. * - * XXX: This enforcement is actually incomplete, since we don't keep + * This enforcement is arguably incomplete, since we don't keep * track of access/deny bit combinations; so, e.g., we allow: * * OPEN allow read, deny write @@ -372,6 +374,10 @@ static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = { * DOWNGRADE allow read, deny none * * which we should reject. + * + * But you could also argue that our current code is already overkill, + * since it only exists to return NFS4ERR_INVAL on incorrect client + * behavior. */ static unsigned int bmap_to_share_mode(unsigned long bmap) diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index e73bdbb1634ab..6eb3c7157214b 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -568,6 +568,10 @@ struct nfs4_ol_stateid { struct list_head st_locks; struct nfs4_stateowner *st_stateowner; struct nfs4_clnt_odstate *st_clnt_odstate; +/* + * These bitmasks use 3 separate bits for READ, ALLOW, and BOTH; see the + * comment above bmap_to_share_mode() for explanation: + */ unsigned char st_access_bmap; unsigned char st_deny_bmap; struct nfs4_ol_stateid *st_openstp;